U.S. patent application number 09/925579 was filed with the patent office on 2002-04-04 for plasma processing apparatus and system, performance validation system and inspection method therefor.
This patent application is currently assigned to Alps Electric Co., Ltd. and Tadahiro Ohmi. Invention is credited to Nakano, Akira, Ohmi, Tadahiro.
Application Number | 20020038688 09/925579 |
Document ID | / |
Family ID | 26597916 |
Filed Date | 2002-04-04 |
United States Patent
Application |
20020038688 |
Kind Code |
A1 |
Nakano, Akira ; et
al. |
April 4, 2002 |
Plasma processing apparatus and system, performance validation
system and inspection method therefor
Abstract
A plasma processing apparatus including a plasma processing
chamber having a plasma excitation electrode for exciting a plasma,
a radiofrequency generator for supplying a radiofrequency voltage
to the electrode, a radiofrequency feeder connected to the
electrode, and a matching circuit having an input terminal and an
output end. The input terminal is connected to the radiofrequency
generator and the output end is connected to an end of the
radiofrequency feeder so as to achieve impedance matching between
the plasma processing chamber and the radiofrequency generator. A
frequency which is three times a first series resonant frequency
f.sub.0 of the plasma processing chamber, which is measured at the
end of the radiofrequency feeder, is larger than a power frequency
f.sub.e of the radiofrequency waves.
Inventors: |
Nakano, Akira; (Miyagi-ken,
JP) ; Ohmi, Tadahiro; (Miyagi-ken, JP) |
Correspondence
Address: |
Brinks Hofer Gilson & Lione
P.O. Box 10395
Chicago
IL
60610
US
|
Assignee: |
Alps Electric Co., Ltd. and
Tadahiro Ohmi
|
Family ID: |
26597916 |
Appl. No.: |
09/925579 |
Filed: |
August 9, 2001 |
Current U.S.
Class: |
156/345.12 |
Current CPC
Class: |
C23C 16/5096 20130101;
C23C 16/52 20130101; H01J 37/32165 20130101; H01J 37/32174
20130101; H01J 37/32091 20130101 |
Class at
Publication: |
156/345 |
International
Class: |
C23F 001/02 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 11, 2000 |
JP |
2000-245347 |
Sep 22, 2000 |
JP |
2000-289488 |
Claims
What is claimed is:
1. A plasma processing apparatus comprising: a plasma processing
chamber having a plasma excitation electrode for exciting a plasma;
a radiofrequency generator for supplying a radiofrequency voltage
to the electrode; a radiofrequency feeder connected to the
electrode; and a matching circuit having an input terminal and an
output end, wherein the input terminal is connected to the
radiofrequency generator and the output end is connected to an end
of the radiofrequency feeder so as to achieve impedance matching
between the plasma processing chamber and the radiofrequency
generator, wherein a frequency which is three times a first series
resonant frequency f.sub.0 of the plasma processing chamber which
is measured at the end of the radiofrequency feeder is larger than
a power frequency f.sub.e of the radiofrequency waves.
2. A plasma processing apparatus according to claim 1, wherein a
frequency of 1.3 times the first series resonant frequency f.sub.0
is larger than a power frequency f.sub.e.
3. A plasma processing apparatus according to claim 2, wherein the
first series resonant frequency f.sub.0 is larger than three times
the power frequency f.sub.e.
4. A plasma processing apparatus according to claim 3, wherein a
series resonant frequency f.sub.0, which is defined by a
capacitance between the plasma excitation electrode and a counter
electrode for generating the plasma in cooperation with the plasma
excitation electrode is larger than three times the power frequency
f.sub.e.
5. A plasma processing apparatus according to claim 4, wherein the
plasma excitation electrode and the counter electrode are of a
parallel plate type, and the series resonant frequency f.sub.0, and
the power frequency f.sub.e satisfy the relationship: 4 f 0 ' >
d f e wherein d represents the distance between the plasma
excitation electrode and the counter electrode, and .delta.
represents the sum of the distance between the plasma excitation
electrode and the generated plasma and the distance between the
counter electrode and the generated plasma.
6. A plasma processing apparatus according to claim 1, further
comprising a resonant frequency measuring terminal for measuring
the resonant frequency of the plasma processing chamber, in the
vicinity of the end of the radiofrequency feeder.
7. A plasma processing apparatus according to claim 6, further
comprising a switch provided between the radiofrequency feeder and
the resonant frequency measuring terminal, wherein the switch
electrically disconnects the end of the radiofrequency feeder from
the resonant frequency measuring terminal and connects the end of
the radiofrequency feeder to the output end of the matching circuit
in a plasma excitation mode in which the plasma is excited, whereas
the switch electrically connects the end of the radiofrequency
feeder to the resonant frequency measuring terminal and disconnects
the end of the radiofrequency feeder from the resonant frequency
measuring terminal in a measuring mode in which the resonant
frequency of the plasma processing chamber is measured.
8. A plasma processing apparatus according to claim 6, further
comprising a resonant frequency measuring unit which is detachably
connected to the resonant frequency measuring terminal.
9. A plasma processing apparatus according to claim 8, wherein the
resonant frequency characteristics in the plasma excitation mode
and the resonant frequency characteristics in the measuring mode
are set to be equal to each other.
10. A performance validation system for a plasma processing
apparatus according to claim 1, the system comprising: at least one
client terminal; and performance information providing means for
providing performance information to said at least one client
terminal, wherein the performance information comprises standard
operation information regarding general information of the plasma
processing apparatus and operation and maintenance information
regarding specific information of the plasma processing apparatus,
wherein said at least one client terminal has at least one function
of requesting the display of performance information and uploading
the operation and maintenance information to the performance
information providing means.
11. The performance validation system for the plasma processing
apparatus according to claim 10, wherein the standard performance
information and the operation and maintenance information comprise
information regarding a first series resonant frequency
f.sub.0.
12. The performance validation system for the plasma processing
apparatus according to claim 11, wherein the standard performance
information is used as a catalog or a specification document.
13. A plasma processing apparatus comprising a plurality of plasma
processing chamber units, each plasma processing chamber unit
comprising: a plasma processing chamber having a plasma excitation
electrode for exciting a plasma; a radiofrequency generator for
supplying a radiofrequency voltage to the plasma excitation
electrode; a radiofrequency feeder connected to the plasma
excitation electrode; and a matching circuit having an input
terminal and an output terminal, wherein the input terminal is
connected to the radiofrequency generator and the output terminal
is connected to the radiofrequency feeder so as to achieve
impedance matching between the plasma processing chamber and the
radiofrequency generator, wherein a variation, defined by
(A.sub.max-A.sub.min)/(A.sub.max+A.sub.min), between the maximum
frequency A.sub.max and the minimum frequency A.sub.min among
radiofrequency characteristics A of the plurality of plasma
processing chambers has a predetermined value, wherein, in each
plasma processing chamber unit, the radiofrequency characteristic A
thereof is measured at a measuring point which is at the end of the
corresponding radiofrequency feeder connected to the output
terminal of the corresponding matching circuit.
14. A plasma processing apparatus comprising a plurality of plasma
processing chamber units, each plasma processing chamber unit
comprising: a plasma processing chamber having a plasma excitation
electrode for exciting a plasma; a radiofrequency generator for
supplying a radiofrequency voltage to the plasma excitation
electrode; a radiofrequency feeder connected to the plasma
excitation electrode; and a matching circuit having an input
terminal and an output terminal, wherein the input terminal is
connected to the radiofrequency generator via a radiofrequency feed
line, whereas the output terminal is connected to the
radiofrequency feeder so as to achieve impedance matching between
the plasma processing chamber and the radiofrequency generator,
wherein a variation, defined by
(A.sub.max-A.sub.min)/(A.sub.max+A.sub.min) between the maximum
frequency A.sub.max and the minimum frequency A.sub.min among
radiofrequency characteristics A of the plurality of plasma
processing chambers has a predetermined value, wherein, in each
plasma processing chamber unit, the radiofrequency characteristic A
thereof is measured at a measuring point which is the
radiofrequency-generator-side end of the radiofrequency feed line
connected to the respective radiofrequency generator.
15. A plasma processing apparatus comprising a plurality of plasma
processing chamber units, each plasma processing chamber unit
comprising; a plasma processing chamber having a plasma excitation
electrode for exciting a plasma; a radiofrequency generator for
supplying a radiofrequency voltage to the plasma excitation
electrode; a radiofrequency feeder connected to the plasma
excitation electrode; and a matching circuit having an input
terminal and an output terminal, wherein the input terminal is
connected to the radiofrequency generator via a radiofrequency feed
line, whereas the output terminal is connected to the
radiofrequency feeder so as to achieve impedance matching between
the plasma processing chamber and the radiofrequency generator,
wherein a variation, defined by
(A.sub.max-A.sub.min)/(A.sub.max+A.sub.min) between the maximum
frequency A.sub.max and the minimum frequency A.sub.min among
radiofrequency characteristics A of the plurality of plasma
processing chambers has a predetermined value, wherein, in each
plasma processing chamber unit, the radiofrequency characteristic A
thereof is measured at a measuring point which is the input
terminal connected to the corresponding radiofrequency feed
line.
16. A plasma processing apparatus according to claim 13, wherein
the predetermined value is less than 0.1.
17. A plasma processing apparatus according to claim 14, wherein
the predetermined value is less than 0.1.
18. A plasma processing apparatus according to claim 15, wherein
the predetermined value is less than 0.1.
19. A plasma processing apparatus according to claim 13, wherein
each radiofrequency characteristic A is any one of a resonant
frequency f, an impedance Z.sub.e at the frequency of the
radiofrequency generator, a resistance R.sub.e at the frequency of
the radiofrequency generator, and a reactance X.sub.e at the
frequency of the radiofrequency generator.
20. A plasma processing apparatus according to claim 14, wherein
each radiofrequency characteristic A is any one of a resonant
frequency f, an impedance Z.sub.e at the frequency of the
radiofrequency generator, a resistance R.sub.e at the frequency of
the radiofrequency generator, and a reactance X.sub.e at the
frequency of the radiofrequency generator.
21. A plasma processing apparatus according to claim 15, wherein
each radiofrequency characteristic A is any one of a resonant
frequency f, an impedance Z.sub.e at the frequency of the
radiofrequency generator, a resistance R.sub.e at the frequency of
the radiofrequency generator, and a reactance X.sub.e at the
frequency of the radiofrequency generator.
22. A plasma processing apparatus according to claim 13, wherein
each radiofrequency characteristic A is a first series resonant
frequency f.sub.0.
23. A plasma processing apparatus according to claim 14, wherein
each radiofrequency characteristic A is a first series resonant
frequency f.sub.0.
24. A plasma processing apparatus according to claim 15, wherein
each radiofrequency characteristic A is a first series resonant
frequency f.sub.0.
25. A plasma processing apparatus according to claim 13, wherein
three times the first series resonant frequency f.sub.0
corresponding to each plasma processing chamber is larger than the
frequency f.sub.e of the radiofrequency waves.
26. A plasma processing apparatus according to claim 13, wherein
each plasma processing chamber has a measuring terminal for
measuring the radiofrequency characteristic A thereof at the
corresponding measuring point.
27. A plasma processing apparatus according to claim 14, wherein
each plasma processing chamber has a measuring terminal for
measuring the radiofrequency characteristic A thereof at the
corresponding measuring point.
28. A plasma processing apparatus according to claim 15, wherein
each plasma processing chamber has a measuring terminal for
measuring the radiofrequency characteristic A thereof at the
corresponding measuring point.
29. A plasma processing apparatus according to claim 26, wherein
each plasma processing chamber has a switch in the vicinity of the
corresponding measuring point in which the switch electrically
disconnects the measuring point from the measuring terminal and
connects the radiofrequency feeder to the radiofrequency generator
in a plasma excitation mode in which the plasma is excited, whereas
the switch electrically connects the measuring point to the
measuring terminal and disconnects the radiofrequency generator
from the measuring point in a measuring mode in which the
radiofrequency characteristic A of the corresponding plasma
processing chamber is measured.
30. A plasma processing apparatus according to claim 27, wherein
each plasma processing chamber has a switch in the vicinity of the
corresponding measuring point in which the switch electrically
disconnects the measuring point from the measuring terminal and
connects the radiofrequency feeder to the radiofrequency generator
in a plasma excitation mode in which the plasma is excited, whereas
the switch electrically connects the measuring point to the
measuring terminal and disconnects the radiofrequency generator
from the measuring point in a measuring mode in which the
radiofrequency characteristic A of the corresponding plasma
processing chamber is measured.
31. A plasma processing apparatus according to claim 28, wherein
each plasma processing chamber has a switch in the vicinity of the
corresponding measuring point in which the switch electrically
disconnects the measuring point from the measuring terminal and
connects the radiofrequency feeder to the radiofrequency generator
in a plasma excitation mode in which the plasma is excited, whereas
the switch electrically connects the measuring point to the
measuring terminal and disconnects the radiofrequency generator
from the measuring point in a measuring mode in which the
radiofrequency characteristic A of the corresponding plasma
processing chamber is measured.
32. A plasma processing system comprising a plurality of plasma
processing apparatuses, each plasma processing apparatus
comprising: a plasma processing chamber having a plasma excitation
electrode for exciting a plasma; a radiofrequency generator for
supplying a radiofrequency voltage to the plasma excitation
electrode; a radiofrequency feeder connected to the plasma
excitation electrode; and a matching circuit having an input
terminal and an output terminal, wherein the input terminal is
connected to the radiofrequency generator and the output terminal
is connected to the radiofrequency feeder so as to achieve
impedance matching between the plasma processing chamber and the
radiofrequency generator, wherein a variation, defined by
(A.sub.max-A.sub.min)/(A.sub.max+A.sub.min), between the maximum
frequency A.sub.max and the minimum frequency A.sub.min among
radiofrequency characteristics A of the plurality of plasma
processing chambers has a predetermined value, wherein, in each
plasma processing chamber, the radiofrequency characteristic A
thereof is measured at a measuring point which is at the end of the
corresponding radiofrequency feeder connected to the output
terminal of the corresponding matching circuit.
33. A plasma processing system comprising a plurality of plasma
processing apparatuses, each plasma processing apparatus
comprising: a plasma processing chamber having a plasma excitation
electrode for exciting a plasma; a radiofrequency generator for
supplying a radiofrequency voltage to the plasma excitation
electrode; a radiofrequency feeder connected to the plasma
excitation electrode; and a matching circuit having an input
terminal and an output terminal, wherein the input terminal is
connected to the radiofrequency generator via a radiofrequency feed
line, whereas the output terminal is connected to the
radiofrequency feeder so as to achieve impedance matching between
the plasma processing chamber and the radiofrequency generator,
wherein a variation, defined by
(A.sub.max-A.sub.min)/(A.sub.max+A.sub.min), between the maximum
frequency A.sub.max and the minimum frequency A.sub.min among
radiofrequency characteristics A of the plurality of plasma
processing chambers has a predetermined value, wherein, in each
plasma processing chamber, the radiofrequency characteristic A
thereof is measured at a measuring point which is the
radiofrequency-generator-side end of the radiofrequency feed line
connected to the respective radiofrequency generator.
34. A plasma processing system comprising a plurality of plasma
processing apparatuses, each plasma processing apparatus
comprising: a plasma processing chamber having a plasma excitation
electrode for exciting a plasma; a radiofrequency generator for
supplying a radiofrequency voltage to the plasma excitation
electrode; a radiofrequency feeder connected to the plasma
excitation electrode; and a matching circuit having an input
terminal and an output terminal, wherein the input terminal is
connected to the radiofrequency generator via a radiofrequency feed
line, whereas the output terminal is connected to the
radiofrequency feeder so as to achieve impedance matching between
the plasma processing chamber and the radiofrequency generator,
wherein a variation, defined by
(A.sub.max-A.sub.min)/(A.sub.max+A.sub.min), between the maximum
frequency A.sub.max and the minimum frequency A.sub.min among
radiofrequency characteristics A of the plurality of plasma
processing chambers has a predetermined value, wherein, in each
plasma processing chamber, the radiofrequency characteristic A
thereof is measured at a measuring point which is the input
terminal connected to the corresponding radiofrequency feed
line.
35. A plasma processing system according to claim 32, wherein the
predetermined value is less than 0.1.
36. A plasma processing system according to claim 33, wherein the
predetermined value is less than 0.1.
37. A plasma processing system according to claim 34, wherein the
predetermined value is less than 0.1.
38. A plasma processing system according to claim 32, wherein each
radiofrequency characteristic A is any one of a resonant frequency
f, an impedance Z.sub.e at the frequency of the radiofrequency
generator, a resistance R.sub.e at the frequency of the
radiofrequency generator, and a reactance X.sub.e at the frequency
of the radiofrequency generator.
39. A plasma processing system according to claim 33, wherein each
radiofrequency characteristic A is any one of a resonant frequency
f, an impedance Z.sub.e at the frequency of the radiofrequency
generator, a resistance R.sub.e at the frequency of the
radiofrequency generator, and a reactance X.sub.e at the frequency
of the radiofrequency generator.
40. A plasma processing system according to claim 34, wherein each
radiofrequency characteristic A is any one of a resonant frequency
f, an impedance Z.sub.e at the frequency of the radiofrequency
generator, a resistance R.sub.e at the frequency of the
radiofrequency generator, and a reactance X.sub.e at the frequency
of the radiofrequency generator.
41. A plasma processing system according to claim 32, wherein each
radiofrequency characteristic A is a first series resonant
frequency f.sub.0.
42. A plasma processing system according to claim 33, wherein each
radiofrequency characteristic A is a first series resonant
frequency f.sub.0.
43. A plasma processing system according to claim 34, wherein each
radiofrequency characteristic A is a first series resonant
frequency f.sub.0.
44. A plasma processing system according to claim 32, wherein three
times the first series resonant frequency f.sub.0 corresponding to
each plasma processing chamber is larger than the frequency f.sub.e
of the radiofrequency waves.
45. A plasma processing system according to claim 33, wherein each
plasma processing chamber has a measuring terminal for measuring
the radiofrequency characteristic A thereof at the corresponding
measuring point.
46. A plasma processing system according to claim 34, wherein each
plasma processing chamber has a measuring terminal for measuring
the radiofrequency characteristic A thereof at the corresponding
measuring point.
47. A plasma processing system according to claim 35, wherein each
plasma processing chamber has a measuring terminal for measuring
the radiofrequency characteristic A thereof at the corresponding
measuring point.
48. A plasma processing apparatus according to claim 44, wherein
each plasma processing chamber has a switch in the vicinity of the
corresponding measuring point in which the switch electrically
disconnects the measuring point from the measuring terminal and
connects the radiofrequency feeder to the radiofrequency generator
in a plasma excitation mode in which the plasma is excited, whereas
the switch electrically connects the measuring point to the
measuring terminal and disconnects the radiofrequency generator
from the measuring point in a measuring mode in which the
radiofrequency characteristic A of the corresponding plasma
processing chamber is measured.
49. A plasma processing apparatus according to claim 45, wherein
each plasma processing chamber has a switch in the vicinity of the
corresponding measuring point in which the switch electrically
disconnects the measuring point from the measuring terminal and
connects the radiofrequency feeder to the radiofrequency generator
in a plasma excitation mode in which the plasma is excited, whereas
the switch electrically connects the measuring point to the
measuring terminal and disconnects the radiofrequency generator
from the measuring point in a measuring mode in which the
radiofrequency characteristic A of the corresponding plasma
processing chamber is measured.
50. A plasma processing apparatus according to claim 46, wherein
each plasma processing chamber has a switch in the vicinity of the
corresponding measuring point in which the switch electrically
disconnects the measuring point from the measuring terminal and
connects the radiofrequency feeder to the radiofrequency generator
in a plasma excitation mode in which the plasma is excited, whereas
the switch electrically connects the measuring point to the
measuring terminal and disconnects the radiofrequency generator
from the measuring point in a measuring mode in which the
radiofrequency characteristic A of the corresponding plasma
processing chamber is measured.
51. A performance validation system for a plasma processing
apparatus according to claim 13, the system comprising: at least
one client terminal; and performance information providing means
for providing performance information to said at least one client
terminal, wherein the performance information comprises standard
operation information regarding general information of the plasma
processing apparatus and operation and maintenance information
regarding specific information of the plasma processing apparatus,
wherein said at least one client terminal has at least one function
of requesting the display of performance information and uploading
the operation and maintenance information to the performance
information providing means.
52. A performance validation system for a plasma processing
apparatus according to claim 14, the system comprising: at least
one client terminal; and performance information providing means
for providing performance information to said at least one client
terminal, wherein the performance information comprises standard
operation information regarding general information of the plasma
processing apparatus and operation and maintenance information
regarding specific information of the plasma processing apparatus,
wherein said at least one client terminal has at least one function
of requesting the display of performance information and uploading
the operation and maintenance information to the performance
information providing means.
53. A performance validation system for a plasma processing
apparatus according to claim 15, the system comprising: at least
one client terminal; and performance information providing means
for providing performance information to said at least one client
terminal, wherein the performance information comprises standard
operation information regarding general information of the plasma
processing apparatus and operation and maintenance information
regarding specific information of the plasma processing apparatus,
wherein said at least one client terminal has at least one function
of requesting the display of performance information and uploading
the operation and maintenance information to the performance
information providing means.
54. A performance validation system according to claim 51, wherein
the performance information includes the variation of the
radiofrequency characteristics A.
55. A performance validation system according to claim 52, wherein
the performance information includes the variation of the
radiofrequency characteristics A.
56. A performance validation system according to claim 53, wherein
the performance information includes the variation of the
radiofrequency characteristics A.
57. A performance validation system for a plasma processing system
according to claim 32, the system comprising: at least one client
terminal; and performance information providing means for providing
performance information to said at least one client terminal,
wherein the performance information comprises standard operation
information regarding general information of the plasma processing
apparatus and operation and maintenance information regarding
specific information of the plasma processing apparatus, wherein
said at least one client terminal has at least one function of
requesting the display of performance information and uploading the
operation and maintenance information to the performance
information providing means.
58. A performance validation system for a plasma processing system
according to claim 33, the system comprising: at least one client
terminal; and performance information providing means for providing
performance information to said at least one client terminal,
wherein the performance information comprises standard operation
information regarding general information of the plasma processing
apparatus and operation and maintenance information regarding
specific information of the plasma processing apparatus, wherein
said at least one client terminal has at least one function of
requesting the display of performance information and uploading the
operation and maintenance information to the performance
information providing means.
59. A performance validation system for a plasma processing system
according to claim 33, the system comprising: at least one client
terminal; and performance information providing means for providing
performance information to said at least one client terminal,
wherein the performance information comprises standard operation
information regarding general information of the plasma processing
apparatus and operation and maintenance information regarding
specific information of the plasma processing apparatus, wherein
said at least one client terminal has at least one function of
requesting the display of performance information and uploading the
operation and maintenance information to the performance
information providing means.
60. A performance validation system according to claim 57, wherein
the performance information includes the variation of the
radiofrequency characteristics A.
61. A performance validation system according to claim 58, wherein
the performance information includes the variation of the
radiofrequency characteristics A.
62. A performance validation system according to claim 59, wherein
the performance information includes the variation of the
radiofrequency characteristics A.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a plasma processing
apparatus, and a performance validation system of the plasma
processing apparatus, which use radiofrequency voltage to improve
the power consumption efficiency and the coating
characteristics.
[0003] 2. Description of the Related Art FIG. 18 illustrates an
example of a conventional dual-frequency excitation plasma
processing apparatus which performs a plasma process such as
chemical vapor deposition (CVD), sputtering, dry etching, ashing,
or the like.
[0004] In the plasma processing apparatus shown in FIG. 18, a
matching circuit 2A is inserted between a radiofrequency generator
1 and a plasma excitation electrode 4. The matching circuit 2A
serves as a circuit that matches the impedance between the
radiofrequency generator 1 and the excitation electrode 4.
[0005] Radiofrequency voltage from the radiofrequency generator 1
is fed to the plasma excitation electrode 4 via the matching
circuit 2A and a feed plate 3. The matching circuit 2A is
accommodated in a matching box 2, which is a housing composed of a
conductive material. The plasma excitation electrode 4 and the feed
plate 3 are covered by a chassis 21 made of a conductor.
[0006] The plasma excitation electrode 4 is provided with a
projection 4a at the lower side thereof. A shower plate 5 having a
number of holes 7 is provided under the plasma excitation electrode
4, and is in contact with the projection 4a. The plasma excitation
electrode 4 and the shower plate 5 define a space 6. A gas feeding
tube 17 comprising a conductor is connected to the space 6. The gas
feeding tube 17 is provided with an insulator 17a at the middle
thereof so as to insulate the plasma excitation electrode 4 from
the gas source.
[0007] Gas flowing from the gas feeding tube 17 is fed inside a
chamber space 60, composed of a chamber wall 10, via the holes 7 in
the shower plate 5. An insulator 9 is disposed between the chamber
wall 10 and the plasma excitation electrode 4 (cathode) to provide
insulation therebetween. The exhaust system is omitted from the
drawing.
[0008] A wafer susceptor (susceptor electrode) 8, which receives a
substrate 16 and also serves as a plasma excitation electrode, is
installed inside the chamber space 60. A susceptor shield 12 is
disposed under the wafer susceptor 8.
[0009] The susceptor shield 12 comprises a shield supporting plate
12A for receiving the susceptor electrode 8 and a cylindrical
supporting tube 12B extending downward from the center of the
shield supporting plate 12A. The supporting tube 12B penetrates a
chamber bottom 10A, and the lower portion of the supporting tube
12B and the chamber bottom 10A are hermetically sealed with bellows
11.
[0010] The shaft 13 and the susceptor electrode 8 are electrically
isolated from the susceptor shield 12 by a gap between the
susceptor shield 12 and the susceptor electrode 8 and by insulators
12C provided around the shaft 13. The insulators 12C also serve to
maintain a high vacuum in the chamber space 60. The susceptor
electrode 8 and the susceptor shield 12 can be moved upward and
downward by the bellows 11 in order to control the distance between
plasma excitation electrodes 4 and 8.
[0011] The susceptor electrode 8 is connected to a second
radiofrequency generator 15 via the shaft 13 and a matching circuit
accommodated in a matching box 14. The chamber wall 10 and the
susceptor shield 12 have equal DC potentials.
[0012] FIG. 19 illustrates another example of a conventional plasma
processing apparatus. Unlike the plasma processing apparatus shown
in FIG. 18, the plasma processing apparatus shown in FIG. 19 is of
a single-frequency excitation type. In other words, a
radiofrequency voltage is supplied only to the cathode electrode 4.
The susceptor electrode 8 is grounded. Moreover, the matching box
14 and the radiofrequency generator 15 shown in FIG. 18 are not
provided in the apparatus shown in FIG. 19. The susceptor electrode
8 and the chamber wall 10 have equal DC potentials.
[0013] In these conventional plasma processing apparatuses, a
voltage with a frequency of approximately 13.56 MHz is generally
supplied in order to generate a plasma between the electrodes 4 and
8. A plasma process such as CVD, sputtering, dry etching, ashing,
or the like is then performed using the plasma.
[0014] However, in the above-described plasma processing
apparatuses, the power consumption efficiency, i.e., the ratio of
the power fed into the plasma excitation electrode 4 from the
radiofrequency generator 1 to the power consumed in the plasma, is
not necessarily satisfactory. Moreover, as the frequency of the
voltage fed from the radiofrequency generator is increased, the
decrease in the consumption efficiency of the plasma processing
apparatus becomes more significant. The consumption efficiency is
also decreased when the size of the substrate is increased.
[0015] As a consequence of this low power consumption efficiency,
the density of the generated plasma cannot be increased and the
rate of deposition remains low. Moreover, and by way of example, in
the case of depositing insulating layers, it is difficult to
deposit a layer having a high isolation voltage.
[0016] The operation validation and the evaluation of the
above-described plasma processing apparatuses have been conducted
by actually performing a process such as deposition and then
evaluating the deposition characteristics thereof as follows.
[0017] (1) Deposition rates and planar uniformity
[0018] The process of determining and evaluating deposition rates
and planar uniformity includes the following:
[0019] Step 1: Depositing a desired layer on a substrate by a
plasma-enhanced CVD process;
[0020] Step 2: Patterning a resist layer;
[0021] Step 3: Dry-etching the layer;
[0022] Step 4: Separating the resist layer by ashing;
[0023] Step 5: Measuring step differences in the layer thickness
using a displacement meter;
[0024] Step 6: Calculating deposition rates from the deposition
time and the layer thickness; and
[0025] Step 7: Measuring the planar uniformity at 16 points on a
6-inch substrate surface.
[0026] (2) BHF etching rate
[0027] The process of determining etching rates includes the
following:
[0028] A resist mask is patterned as in Steps 1 and 2 above;
[0029] Step 3: Immersing the substrate in a BHF solution for one
minute;
[0030] Step 4: Rinsing the substrate with deionized water, drying
the substrate, and separating the resist mask using a mixture of
sulfuric acid and hydrogen peroxide
(H.sub.2SO.sub.4+H.sub.2O.sub.2);
[0031] Step 5: Measuring the step difference as in Step 5 above;
and
[0032] Step 6: Calculating the etching rate from the immersion time
and the step differences.
[0033] (3) Isolation voltage
[0034] The process of determining and evaluating the isolation
voltage includes the following:
[0035] Step 1: Depositing a conductive layer on a glass substrate
by a sputtering method and patterning the conductive layer to form
a lower electrode;
[0036] Step 2: Depositing an insulation layer by a plasma-enhanced
CVD method;
[0037] Step 3: Forming an upper electrode as in Step 1;
[0038] Step 4: Forming a contact hole for the lower electrode;
[0039] Step 5: Measuring the current-voltage characteristics (I-V
characteristics) of the upper and lower electrodes by using probes
while applying a voltage of approximately 200 V or less; and
[0040] Step 6: defining the isolation voltage as the voltage V at
100 pA corresponding 1 .mu.A/cm.sup.2 in a 100 .mu.m square
electrode.
[0041] A plasma processing apparatus has been required that can
achieve a higher plasma processing rate (the deposition rate or the
processing speed), increased productivity, and uniformity of the
plasma processing in the planar direction of the substrates to be
treated (uniformity in the distribution of the layer thickness in
the planar direction and uniformity in the distribution of the
process variation in the planar direction).
[0042] However, the size of substrates has increased in recent
years, the requirement for uniformity in the planar direction is
becoming more difficult to achieve. Moreover, as the size of the
substrate has increased, the power delivered has also increased to
the order of kilowatts, thus increasing power consumption.
Accordingly, as the capacity of the power supply increases, both
the cost for developing the power supply and the power consumption
during the operation of the apparatus are increased. In this
respect, it is desirable to reduce the operation costs.
[0043] Furthermore, an increase in power consumption leads to an
increase in emission of carbon dioxide, which places a burden on
the environment. Since the power consumption is increased by the
combination of an increase in the size of substrates and low power
consumption efficiency, there is a growing demand to reduce the
carbon dioxide emission.
[0044] The density of the plasma generated can be improved by
increasing the plasma excitation frequency. For example, a
frequency in the VHF band of 30 MHz or more can be used instead of
the conventional 13.56 MHz. Thus, one possible way to improve the
deposition rate of a deposition apparatus such as a plasma-enhanced
CVD apparatus is to employ a higher plasma excitation
frequency.
[0045] Another type of plasma processing apparatus is one having a
plurality of plasma chambers. Such a plasma processing apparatus is
also required to achieve a higher plasma processing rate (the
deposition rate or the processing speed), increased productivity,
and uniformity of the plasma processing in the planar direction of
the substrates (uniformity in the distribution of the layer
thickness in the planar direction and uniformity in the
distribution of the process variation in the planar direction),
even when the substrates are treated in different plasma chambers.
There is also a demand to eliminate operational differences among
the plurality of the plasma chambers, thus avoiding processing
variations.
[0046] Moreover, it is required that the respective plasma chambers
of the plasma processing apparatus having plural plasma chambers
achieve substantially the same plasma processing results by using
the same process recipe specifying external parameters such as the
flow/pressure of the gas supplied, power supply, and treatment
time.
[0047] At the time of initial installation or maintenance of the
plasma processing apparatus, there is a demand to reduce the amount
of time required for adjusting the apparatus to eliminate
differences among the plural plasma chambers and processing
variations, thereby achieving substantially the same process
results using the same process recipe. A reduction of the cost
required for such an adjustment is also required.
[0048] Furthermore, it is also required that a plasma processing
system equipped with a plurality of the above-described plasma
processing apparatuses eliminate plasma processing variations among
individual plasma chambers of the individual plasma processing
apparatuses.
[0049] The conventional plasma processing apparatus described above
is, however, designed to use a power having a frequency of
approximately 13.56 MHz and is not suited for higher frequencies.
To be more specific, the units to which the radiofrequency voltage
is delivered, i.e., the chambers in which plasma processing is
carried out, are designed without taking into an account
radiofrequency characteristics such as impedance and resonance
frequency characteristics, and thus have the following
problems.
[0050] First, when a power having a frequency exceeding 13.56 MHz
is delivered, no improvement is achieved in the deposition rate
during the deposition process. Moreover, the deposition rate may
even be decreased in some cases.
[0051] Second, although the density of a generated plasma increases
as the frequency increases, the density starts to decrease once its
peak value is reached, eventually reaching a level at which
glow-discharge is no longer possible, thus rendering further
increases in frequency useless.
[0052] In order to carry out the performance validation and
performance diagnosis of this plasma processing apparatus employing
processes (1) to (3) described above, the apparatus must actually
be operated so as to confirm the validity of the operations.
Furthermore, the treated substrates are required to undergo ex-situ
inspection comprising a plurality of steps.
[0053] Since such an inspection requires several days to several
weeks to yield evaluation results, it is desired that the time
required for performance inspection of a plasma processing
apparatus be reduced, especially when the apparatus is in the
development stage.
[0054] The radiofrequency electrical characteristics of each of the
chambers of a plasma processing apparatus or a plasma processing
system are defined by its shape, that is, by the mechanical
dimensions. However, the dimensions of each of the components
constituting each plasma chamber vary due to the mechanical
tolerance permitted during the manufacturing process. When such
components are assembled to make a plasma chamber, the plasma
chamber has variations due to both the mechanical tolerance and the
assembly tolerance. No method has been available for determining
whether the overall plasma chamber has the designed radiofrequency
electrical characteristics since some portions are not measurable
after assembly of the components. Thus, there has been no effective
means for examining differences in radiofrequency electrical
characteristics among the plasma chambers.
[0055] As a consequence, the following problems have arisen.
[0056] A plasma processing apparatus and a plasma processing
system, both comprising a plurality of plasma chambers, are not
designed to eliminate the differences in radiofrequency electrical
characteristics such as impedance and resonant frequency
characteristics among the plasma chambers. Thus, it is possible
that the effective power consumed in each of plasma spaces and the
density of the generated plasma will differ between each of the
plasma chambers.
[0057] Also, the same plasma processing results may not be obtained
even when the same process recipe is applied to these plasma
chambers.
[0058] Accordingly, in order to obtain the same plasma processing
results, external parameters such as gas flow/pressure, power
supply, process time, and the like must be compared with the
process results according to evaluation methods (1) to (3)
described above for each of the plasma chambers so as to determine
the correlation between them. However, the amount of data is
enormous, and it is a practical impossibility to completely carry
out the comparison.
[0059] When the inspection methods such as (1) to (3) described
above are employed to validate and evaluate the operation of the
plasma processing apparatus, it becomes necessary to actually
operate the plasma processing apparatus and to examine the treated
substrates using an ex-situ inspection method comprising a
plurality of steps.
[0060] Such an examination takes several days to several weeks to
yield evaluation results, and the characteristics of the substrates
manufactured during that period, assuming that the manufacturing
line is not stopped, remain unknown during that period. If the
status of the plasma processing apparatus is not satisfactory, the
resulting products will not meet predetermined standards. In this
respect, a method that facilitates maintenance of the plasma
processing apparatus has been demanded.
[0061] Moreover, when the inspection methods such as (1) to (3)
described above are employed to inspect the plasma processing
apparatus, or systems having a plurality of plasma chambers, plural
plasma chambers must be adjusted so as to eliminate the differences
between chambers and processing variations and to obtain the same
processing result using the same process recipe at the time of
initial installation or maintenance/inspection of the apparatus.
The time required for such adjustment may be months. Thus, it has
been demanded that the time required for such adjustment be
reduced. Also, the cost of substrates for inspection, the cost of
processing the substrates for inspection, the labor cost for
workers involved with the adjustment, and so forth are
significantly high, and a reduction in these costs has likewise
been demanded.
SUMMARY OF THE INVENTION
[0062] Accordingly, the objects of the present invention are as
follows.
[0063] A first object of the present invention is to improve the
processing speed, e.g., deposition rate when the present invention
is applied to a deposition apparatus, by increasing the frequency
of the plasma-exciting frequency.
[0064] A second object of the present invention is to improve the
uniformity of the plasma process in the planar direction of the
treated substrate, e.g., improving the thickness distribution in
the planar direction and processing distribution in the planar
direction.
[0065] A third object of the present invention, when applied to a
plasma-enhanced CVD apparatus or a sputtering apparatus, is to
improve the layer characteristics of the deposited layer such as
isolation voltage and the like.
[0066] A fourth object of the present invention is to reduce the
electricity loss by improving the power consumption efficiency so
that the same layer characteristics can be achieved with reduced
power.
[0067] A fifth object of the present invention is to reduce the
operating cost and improve the production efficiency of the plasma
processing apparatus.
[0068] A sixth object of the present invention is to provide a
reference for determining the validity of the plasma chamber
operation other than that determined by examining the treated
substrate.
[0069] A seventh object of the present invention is to provide a
plasma processing apparatus having a plurality of plasma chambers,
the plasma chambers having a uniform radiofrequency electrical
characteristics such as resonant frequency characteristics.
[0070] An eighth object of the present invention is to provide a
plasma processing apparatus having a plurality of plasma chambers
capable of achieving a uniform plasma processing result by using
the same process recipe.
[0071] A ninth object of the present invention is to dispense with
an examination of a vast amount of data regarding the plasma
chambers, and a comparison of the results of inspection methods,
such methods as (1) to (3) described above, with the external
parameters.
[0072] A tenth object of the present invention is to reduce the
time required to adjust the plasma chambers so that the plasma
chambers achieve substantially the same process results by using
the same process recipe.
[0073] An eleventh object of the present invention is to provide a
plasma processing apparatus or system which can be easily
maintained.
[0074] To accomplish the above-described objets, an aspect of the
present invention provides a plasma processing apparatus having a
plasma processing chamber having a plasma excitation electrode for
exciting a plasma, a radio frequency generator for supplying a
radiofrequency voltage to the electrode, a radiofrequency feeder
connected to the electrode, and a matching circuit having an input
end and an output end. The input end of the matching circuit is
connected to the radiofrequency generator and the output end of the
same is connected to an end of the radio frequency feeder to
perform impedance matching between the plasma processing chamber
and the radiofrequency generator. Herein, a first series resonant
frequency f.sub.0 measured at the end of the radio frequency feeder
is set so that three times the first series resonant frequency
f.sub.0 is larger than a power frequency f.sub.e of the
radiofrequency voltage.
[0075] By so setting the first series resonant frequency f.sub.0
that three times the first series resonant frequency f.sub.0 is
larger than the power frequency f.sub.e, power can be efficiently
supplied to the plasma generating space even when a power having a
frequency higher than approximately 13.56 MHz (the frequency
conventionally used) is used. Moreover, when the same frequency as
in the conventional process is supplied, the effective power
consumed in the plasma space can be increased. As a result, the
deposition rate, when the invention is applied to a deposition
apparatus, can be improved.
[0076] Since the first series resonant frequency f.sub.0 is mainly
determined by the factors relating to the mechanical structure
thereof, the first series resonant frequency f.sub.0 differs
according to specific apparatuses. By setting the first series
resonant frequency f.sub.0 to the above-described range, it becomes
possible to provide each of the apparatuses with predetermined
overall radiofrequency electrical characteristics and to achieve
stable plasma generation. As a consequence, a plasma processing
apparatus with an improved operational stability can be
provided.
[0077] The first series resonant frequency f.sub.0 is defined as
follows.
[0078] First, the dependency of the impedance of the plasma
processing chamber on the frequency is examined. More specifically,
the region of the plasma chamber in which measurements are taken is
defined as described below, and the vector quantity (Z, .theta.) of
the impedance in the thus-defined measured region is measured while
varying the measuring voltage in such a range that the power
frequency f.sub.e is included. Considering that the power frequency
f.sub.e is typically set to 13.56 MHz, 27.12 MHz, 40.68 MHz, or the
like, the measuring frequency is varied over the range of 1 MHz to
100 MHz, for example. Next, an impedance characteristic curve and a
phase curve are drawn by plotting the impedance Z and the phase
.theta. versus the measuring frequency. Among the frequencies
assigned to the minima of the impedance Z, the least significant
frequency is defined as the first series resonant frequency
f.sub.0.
[0079] Next, the region of the plasma chamber in which the
impedance measurement is taken will be described.
[0080] The plasma chamber is connected to the radiofrequency
generator via the matching circuit. The measured region starts from
the output end position of the matching circuit and extends toward
the output side of the plasma chamber.
[0081] More particularly, since most of the matching circuits are
provided with a plurality of passive elements so that the impedance
adjustment can be carried out according to the change in the plasma
state inside the plasma chamber, the matching circuit is
disconnected from the plasma processing chamber at the output end
position of the passive element disposed at the last output stage
in the matching circuit during the measurement, and the measured
region starts from that output end position.
[0082] Preferably, the first series resonant frequency f.sub.0 is
set so that 1.3 times the first series resonant frequency f.sub.0
is larger than the power frequency f.sub.e. In this manner, the
density of the generated plasma can be further increased, and the
processing rate can thus be further improved. The deposition rate
can be improved when applied to a deposition apparatus. Because the
density of the generated plasma is increased, it become possible to
improve the characteristics of the deposited layer. For example,
the isolation voltage of the deposited layer can be improved. The
increase in plasma density also results in an improvement in the
uniformity of the deposited layer in the planar direction. Thus,
variations in the layer planar characteristics such as layer
thickness and isolation voltage can be avoided.
[0083] More preferably, the first series resonant frequency f.sub.0
is set to be larger than three times the power frequency f.sub.e.
In this manner, it becomes possible to reduce the power required to
achieve the same processing rate. Thus, the planar uniformity of
the layer and the layer characteristics as conventionally achieved
can be reduced, saving energy and reducing operation costs. When
applied to a deposition apparatus, the deposition rate, the
uniformity in layer thickness, and the isolation voltage can all be
improved.
[0084] Yet more preferably, a series resonant frequency f.sub.0'
defined by the capacitance between the above-described plasma
excitation electrode and a counter electrode, which works in
cooperation with the plasma excitation electrode to generate a
plasma, may also be used. In such a case, the series resonant
frequency f.sub.0' is set to be larger than three times the power
frequency f.sub.e. In this manner, the frequency characteristics of
the capacitance between the above-described electrodes which
generate a plasma can be directly defined, power can be more
efficiently supplied to the plasma emission space, and further
improvements in power consumption efficiency and in processing
efficiency can be achieved.
[0085] The plasma excitation electrode and the counter electrode
may be of a parallel plate type. Herein, the series resonant
frequency f.sub.0' and the power frequency f.sub.e may satisfy the
relationship 1 f 0 ' > d f e ( 1 )
[0086] wherein D represents the distance between the plasma
excitation electrode and the counter electrode, and .delta.
represents the sum of the distance between the plasma excitation
electrode and the generated plasma and the distance between the
counter electrode and the generated plasma.
[0087] A model capacitance between the electrodes during plasma
emission can be obtained from the sum .delta. of the distances of
the portions of the space between electrodes not emitting plasma.
Then, the frequency characteristics defined from this model
capacitance are set in relation to the frequency characteristics
defined from the capacitance between electrodes not emitting
plasma, which is determined by the interelectrode distanced.
[0088] The distance between the parallel-plate-type electrodes can
be considered as .delta. because the generated plasma between the
electrodes can be considered as a conductor. As a result, the
apparent capacitance between the electrodes is d/.delta. times the
capacitance C.sub.0, which is the capacitance when plasma is not
emitted. Since the first series resonant frequency f.sub.0 is
proportional to the reciprocal of the square root of the
capacitance C.sub.0, the series resonant frequency during the
plasma emission is proportional to the reciprocal of the square
root of d/.delta.. Thus, when the value of the first series
resonant frequency f.sub.0 times the reciprocal of the square root
of d/.delta. is set to be larger than the power frequency f.sub.e,
the first series resonant frequency between the electrodes during
plasma emission can be set in relation to the power frequency
f.sub.e, and the power consumption efficiency during plasma
emission can be improved.
[0089] A resonant frequency measuring terminal for measuring the
resonant frequency of the plasma processing chamber may be provided
in the vicinity of the end of the radiofrequency feeder. It becomes
possible to easily measure, using probes, the impedance
characteristics and to define the resonant frequency
characteristics of the plasma chamber without having to
mechanically detach the matching circuit from the conductor for
power supply. Thus, the operation efficiency of the measurement of
the first series resonant frequency f.sub.0 can be improved.
[0090] The plasma processing apparatus further includes a switch
provided between the radiofrequency feeder and the resonant
frequency measuring terminal. The switch electrically disconnects
the end of the radiofrequency feeder from the resonant frequency
measuring terminal and connects the end of the radiofrequency
feeder to the output end of the matching circuit during plasma
excitation. Hereinafter, such a state of the plasma processing
apparatus is referred to as being in "a plasma excitation mode".
The switch electrically connects the end of the radiofrequency
feeder to the resonant frequency measuring terminal and disconnects
the end of the radiofrequency feeder from the resonant frequency
measuring terminal during measurement of the resonant frequency.
Hereinafter, such a state of the plasma processing apparatus is
referred to as being in "a measuring mode". Because the matching
circuit connected in parallel to the plasma chamber to be measured,
as viewed from the impedance measuring terminal, can be detached
using the switch, it becomes unnecessary to mechanically
detach/attach the conductor for power supply from the matching
circuit. Thus, the impedance characteristics of the plasma chamber
can be measured with ease, and the measurement of the first series
resonant frequency f.sub.0 can be performed with an improved
accuracy.
[0091] The plasma processing apparatus may include a measuring unit
which is detachably connected to the resonant frequency measuring
terminal. The impedance meter can avoid electrical influence acting
during plasma emission by detaching the impedance measuring
terminal and the impedance meter from the plasma chamber or by
operating the switch. When a plurality of plasma chambers are
provided, one impedance meter may perform the measurement of these
plasma chambers. Thus, the impedance characteristics, measurement
of the resonant frequency characteristics, and measurement of the
first series resonant frequency f.sub.0 can be easily carried out
simply by operating the switch, without having to detach the
matching circuit from the plasma chamber (plasma processing room)
and detach the probes of the impedance meter from the impedance
measuring terminal.
[0092] The resonant frequency characteristic in the plasma
excitation mode and the resonant frequency characteristic in the
measuring mode may be set to equal each other. In this manner,
neither correction nor reduction is necessary to obtain the actual
value of the first series resonant frequency f.sub.0. Thus, the
efficiency of operation can be improved.
[0093] In this invention, the plasma processing apparatus may be a
dual-frequency excitation type having a first radiofrequency
generator, a radiofrequency electrode coupled to the first
radiofrequency generator, a radiofrequency electrode-side matching
box including a matching circuit for performing impedance matching
between the first radiofrequency generator and the radiofrequency
electrode, a second radiofrequency generator, a susceptor
electrode, which is connected to the second radiofrequency
generator and disposed to oppose the radiofrequency electrode, for
supporting a substrate to be treated, and a susceptor electrode
side matching box including a matching circuit for performing
impedance matching between the second radiofrequency generator and
the susceptor electrode. In such a case, the above-described
settings can be applied to the power frequency of the second
radiofrequency generator and the first series resonant frequency
f.sub.0 measured from the output end of the
susceptor-electrode-side matching circuit.
[0094] Another aspect of the present invention provides a
performance validation system for the above-described plasma
processing apparatus. The system includes at least one client
terminal and performance information providing means for providing
performance information to the at least one client terminal. The
performance information includes standard operation information
regarding general information of the plasma processing apparatus,
and operation and maintenance information regarding specific
information of the plasma processing apparatus. The client terminal
has at least the functions of requesting the display of performance
information, and uploading the operation and maintenance
information to the performance information providing means. In this
manner, it is possible to provide the customer who is considering
purchasing of the new apparatus with reference information which
would help the customer to make decisions. Also, it is possible to
easily provide the customer who purchased the apparatus with
information regarding the operating state and maintenance state of
the purchased apparatus.
[0095] Preferably, the standard performance information, and the
operation and maintenance information, include information
regarding a first series resonant frequency f.sub.0. When the
above-described performance information includes the information
regarding the first series resonant frequency f.sub.0, which serves
as one of parameters of the plasma processing apparatus, it is
possible to provide the customer with information that allows a
customer to examine the performance of the purchased plasma
processing apparatus, and information that allows a customer
considering purchasing the apparatus with reference information
which would help the customer making the decision.
[0096] The above-described standard performance information may be
used as catalog or a specification statement when output through
the client terminal.
[0097] According to another aspect of the present invention, a
plasma processing apparatus comprises a plurality of plasma
processing chamber units, each plasma processing chamber unit
comprising a plasma processing chamber having a plasma excitation
electrode for exciting a plasma, a radiofrequency generator for
supplying a radiofrequency voltage to the plasma excitation
electrode, a radiofrequency feeder connected to the plasma
excitation electrode, and a matching circuit having an input
terminal and an output terminal, wherein the input terminal is
connected to the radiofrequency generator and the output terminal
is connected to the radiofrequency feeder so as to achieve
impedance matching between the plasma processing chamber and the
radiofrequency generator, wherein a variation, defined by
(A.sub.max-A.sub.min)/(A.sub.max+A.sub.min), between the maximum
frequency A.sub.max and the minimum frequency A.sub.min among
radiofrequency characteristics A of the plurality of plasma
processing chambers has a predetermined value. Further wherein, in
each plasma processing chamber unit, the radiofrequency
characteristic A thereof is measured at a measuring point which is
at the end of the corresponding radiofrequency feeder connected to
the output terminal of the corresponding matching circuit.
[0098] According to another aspect of the present invention, a
plasma processing apparatus comprises a plurality of plasma
processing chamber units, each plasma processing chamber unit
comprising a plasma processing chamber having a plasma excitation
electrode for exciting a plasma, a radiofrequency generator for
supplying a radiofrequency voltage to the plasma excitation
electrode, a radiofrequency feeder connected to the plasma
excitation electrode, and a matching circuit having an input
terminal and an output terminal, wherein the input terminal is
connected to the radiofrequency generator via a radiofrequency feed
line, and whereas the output terminal is connected to the
radiofrequency feeder so as to achieve impedance matching between
the plasma processing chamber and the radiofrequency generator.
Further wherein a variation, defined by
(A.sub.max-A.sub.min)/(A.sub.max+A.sub.min), between the maximum
frequency A.sub.max and the minimum frequency A.sub.min among
radiofrequency characteristics A of the plurality of plasma
processing chambers has a predetermined value, and wherein, in each
plasma processing chamber unit, the radiofrequency characteristic A
thereof is measured at a measuring point which is the
radiofrequency-generator-side end of the radiofrequency feed line
connected to the respective radiofrequency generator.
[0099] According to another aspect of the present invention, a
plasma processing apparatus comprises a plurality of plasma
processing chamber units, each plasma processing chamber unit
comprising a plasma processing chamber having a plasma excitation
electrode for exciting a plasma, a radiofrequency generator for
supplying a radiofrequency voltage to the plasma excitation
electrode, a radiofrequency feeder connected to the plasma
excitation electrode, and a matching circuit having an input
terminal and an output terminal, wherein the input terminal is
connected to the radiofrequency generator via a radiofrequency feed
line, and whereas the output terminal is connected to the
radiofrequency feeder so as to achieve impedance matching between
the plasma processing chamber and the radiofrequency generator.
Further wherein a variation, defined by
(A.sub.max-A.sub.min)/(A.sub.max+A.sub.min) between the maximum
frequency A.sub.max and the minimum frequency A.sub.min among
radiofrequency characteristics A of the plurality of plasma
processing chambers has a predetermined value, and wherein, in each
plasma processing chamber unit, the radiofrequency characteristic A
thereof is measured at a measuring point which is the input
terminal connected to the corresponding radiofrequency feed
line.
[0100] In these aspects, the predetermined value is preferably less
than 0.1 and more preferably less than 0.03.
[0101] Each radiofrequency characteristic A may be any one of a
resonant frequency f, an impedance Z.sub.e at the frequency of the
radiofrequency generator, a resistance R.sub.e at the frequency of
the radiofrequency generator, and a reactance X.sub.e at the
frequency of the radiofrequency generator. Alternatively, each
radiofrequency characteristic A may be a first series resonant
frequency f.sub.0.
[0102] Preferably, three times the first series resonant frequency
f.sub.0 corresponding to each plasma processing chamber is larger
than the frequency f.sub.e of the radiofrequency waves.
[0103] Preferably, each plasma processing chamber has a measuring
terminal for measuring the radiofrequency characteristic A thereof
at the corresponding measuring point.
[0104] Each plasma processing chamber may have a switch in the
vicinity of the corresponding measuring point in which the switch
electrically disconnects the measuring point from the measuring
terminal and connects the radiofrequency feeder to the
radiofrequency generator in a plasma excitation mode in which the
plasma is excited. The switch electrically connects the measuring
point to the measuring terminal and disconnects the radiofrequency
generator from the measuring point in a measuring mode in which the
radiofrequency characteristic A of the corresponding plasma
processing chamber is measured.
[0105] The radiofrequency characteristic A measured at the output
end of the matching circuit in the excitation mode in which the
switch electrically disconnects the radiofrequency feeder terminal
from the measuring terminal and connects the radiofrequency feeder
terminal to the output end of the matching circuit can be equalized
to the radiofrequency characteristic A measured at the measuring
terminal in the measuring mode in which the switch electrically
connects the radiofrequency feeder terminal to the measuring
terminal and disconnects the radiofrequency feeder terminal from
the output end of the matching circuit.
[0106] According to another aspect of the present invention, a
plasma processing system comprises a plurality of plasma processing
apparatuses, each plasma processing apparatus comprising a plasma
processing chamber having a plasma excitation electrode for
exciting a plasma, a radiofrequency generator for supplying a
radiofrequency voltage to the plasma excitation electrode, a
radiofrequency feeder connected to the plasma excitation electrode,
and a matching circuit having an input terminal and an output end,
wherein the input terminal is connected to the radiofrequency
generator via the radiofrequency feeder, and whereas the output end
is connected to the radiofrequency feeder so as to achieve
impedance matching between the plasma processing chamber and the
radiofrequency generator Further wherein a variation, defined by
(A.sub.max-A.sub.min)/(A.sub.max+A.sub.min), between the maximum
frequency A.sub.max and the minimum frequency A.sub.min among
radiofrequency characteristics A of the plurality of plasma
processing chambers has a predetermined value, and wherein, in each
plasma processing chamber, the radiofrequency characteristic A
thereof is measured at a measuring point which is the
radiofrequency-generator-side end of the radiofrequency feed line
connected to the respective radiofrequency generator.
[0107] According to another aspect of the present invention, a
plasma processing system comprises a plurality of plasma processing
apparatuses, each plasma processing apparatus comprising a plasma
processing chamber having a plasma excitation electrode for
exciting a plasma, a radiofrequency generator for supplying a
radiofrequency voltage to the plasma excitation electrode, a
radiofrequency feeder connected to the plasma excitation electrode,
and a matching circuit having an input terminal and an output
terminal, wherein the input terminal is connected to the
radiofrequency generator via a radiofrequency feed line, and
whereas the output terminal is connected to the radiofrequency
feeder so as to achieve impedance matching between the plasma
processing chamber and the radiofrequency generator. Further
wherein a variation, defined by
(A.sub.max-A.sub.min)/(A.sub.max+A.sub.min) , between the maximum
frequency A.sub.max and the minimum frequency A.sub.min among
radiofrequency characteristics A of the plurality of plasma
processing chambers has a predetermined value, and wherein, in each
plasma processing chamber, the radiofrequency characteristic A
thereof is measured at a measuring point which is the
radiofrequency-generator-side end of the radiofrequency feed line
connected to the respective radiofrequency generator.
[0108] According to another aspect of the present invention, a
plasma processing system comprises a plurality of plasma processing
apparatuses, each plasma processing apparatus comprising a plasma
processing chamber having a plasma excitation electrode for
exciting a plasma, a radiofrequency generator for supplying a
radiofrequency voltage to the plasma excitation electrode, a
radiofrequency feeder connected to the plasma excitation electrode,
and a matching circuit having an input terminal and an output
terminal, wherein the input terminal is connected to the
radiofrequency generator via a radiofrequency feed line, and
whereas the output terminal is connected to the radiofrequency
feeder so as to achieve impedance matching between the plasma
processing chamber and the radiofrequency generator. Further
wherein a variation, defined by
(A.sub.max-A.sub.min)/(A.sub.max+A.sub.min), between the maximum
frequency A.sub.max and the minimum frequency A.sub.min among
radiofrequency characteristics A of the plurality of plasma
processing chambers has a predetermined value, and wherein, in each
plasma processing chamber, the radiofrequency characteristic A
thereof is measured at a measuring point which is the input
terminal connected to the corresponding radiofrequency feed
line.
[0109] As described above, a resonant frequency measuring unit can
be connected to the measuring terminal of each plasma processing
chamber by a switching operation.
[0110] In the present invention, the radiofrequency characteristic
A between the measuring point and the resonant frequency measuring
unit connected to the measuring terminal can be equalized among
these plasma processing chambers.
[0111] The radiofrequency characteristic A measured at the output
end of the matching circuit in the excitation mode in which the
switch electrically disconnects the radiofrequency feeder terminal
from the measuring terminal and connects the radiofrequency feeder
terminal to the output end of the matching circuit can be equalized
to the radiofrequency characteristic A measured at the measuring
terminal in the measuring mode in which the switch electrically
connects the radiofrequency feeder terminal to the measuring
terminal and disconnects the radiofrequency feeder terminal from
the output end of the matching circuit.
[0112] According to another aspect of the present invention, in a
performance validation system for a plasma processing apparatus or
system, the system comprises at least one client terminal, and a
performance information providing means for providing performance
information to the client terminal. The performance information
comprises standard operation information regarding general
information of the plasma processing apparatus, and operation and
maintenance information regarding specific information of the
plasma processing apparatus. The client terminal has at least the
functions of requesting the display of performance information, and
uploading the operation and maintenance information to the
performance information providing means.
[0113] The standard performance information, and the operation and
maintenance information, may comprise information regarding a first
series resonant frequency f.sub.0.
[0114] Moreover, the standard performance information may be used
as a catalog or a specification document.
[0115] According to another aspect of the present invention, in an
inspection method of a plasma processing apparatus comprising a
plurality of plasma processing chamber units, each plasma
processing chamber unit comprises a plasma processing chamber
having a plasma excitation electrode for exciting a plasma, a
radiofrequency generator for supplying a radiofrequency voltage to
the plasma excitation electrode, a radiofrequency feeder connected
to the plasma excitation electrode, and a matching circuit having
an input terminal and an output terminal, wherein the input
terminal is connected to the radiofrequency generator and the
output terminal is connected to the radiofrequency feeder so as to
achieve impedance matching between the plasma processing chamber
and the radiofrequency generator. Further wherein a variation,
defined by (A.sub.max-A.sub.min)/(A.sub.max+A.sub.min) between the
maximum frequency A.sub.max and the minimum frequency A.sub.min
among radiofrequency characteristics A of the plurality of plasma
processing chambers has a predetermined value, and wherein, in each
plasma processing chamber unit, the radiofrequency characteristic A
thereof is measured at a measuring point which is at the end of the
corresponding radiofrequency feeder connected to the output
terminal of the corresponding matching circuit.
[0116] According to another aspect of the present invention, in an
inspection method of a plasma processing apparatus comprising a
plurality of plasma processing chamber units, each plasma
processing chamber unit comprises a plasma processing chamber
having a plasma excitation electrode for exciting a plasma, a
radiofrequency generator for supplying a radiofrequency voltage to
the plasma excitation electrode, a radiofrequency feeder connected
to the plasma excitation electrode, and a matching circuit having
an input terminal and an output terminal, wherein the input
terminal is connected to the radiofrequency generator via a
radiofrequency feed line, and whereas the output terminal is
connected to the radiofrequency feeder so as to achieve impedance
matching between the plasma processing chamber and the
radiofrequency generator. Further wherein a variation, defined by
(A.sub.max-A.sub.min)/(A.sub.max+A.sub.mi- n) between the maximum
frequency A.sub.max and the minimum frequency A.sub.min among
radiofrequency characteristics A of the plurality of plasma
processing chambers has a predetermined value, and wherein, in each
plasma processing chamber unit, the radiofrequency characteristic A
thereof is measured at a measuring point which is the
radiofrequency-generator-side end of the radiofrequency feed line
connected to the respective radiofrequency generator.
[0117] According to another aspect of the present invention, in an
inspection method of a plasma processing apparatus comprising a
plurality of plasma processing chamber units, each plasma
processing chamber unit comprises a plasma processing chamber
having a plasma excitation electrode for exciting a plasma, a
radiofrequency generator for supplying a radiofrequency voltage to
the plasma excitation electrode, a radiofrequency feeder connected
to the plasma excitation electrode, and a matching circuit having
an input terminal and an output terminal, wherein the input
terminal is connected to the radiofrequency generator via a
radiofrequency feed line, and whereas the output terminal is
connected to the radiofrequency feeder so as to achieve impedance
matching between the plasma processing chamber and the
radiofrequency generator. Further wherein a variation, defined by
(A.sub.max-A.sub.min)/(A.sub.max+A.sub.mi- n) between the maximum
frequency A.sub.max and the minimum frequency A.sub.min among
radiofrequency characteristics A of the plurality of plasma
processing chambers has a predetermined value, and wherein, in each
plasma processing chamber unit, the radiofrequency characteristic A
thereof is measured at a measuring point which is the input
terminal connected to the corresponding radiofrequency feed
line.
[0118] According to another aspect of the present invention, in an
inspection method of a plasma processing system comprising a
plurality of plasma processing apparatuses, each plasma processing
apparatus comprises a plasma processing chamber having a plasma
excitation electrode for exciting a plasma, a radiofrequency
generator for supplying a radiofrequency voltage to the plasma
excitation electrode, a radiofrequency feeder connected to the
plasma excitation electrode, and a matching circuit having an input
terminal and an output terminal, wherein the input terminal is
connected to the radiofrequency generator and the output terminal
is connected to the radiofrequency feeder so as to achieve
impedance matching between the plasma processing chamber and the
radiofrequency generator. Further wherein a variation, defined by
(A.sub.max-A.sub.min)/(A.sub.max+A.sub.min), between the maximum
frequency A.sub.max and the minimum frequency A.sub.min among
radiofrequency characteristics A of the plurality of plasma
processing chambers has a predetermined value, and wherein, in each
plasma processing chamber, the radiofrequency characteristic A
thereof is measured at a measuring point which is at the end of the
corresponding radiofrequency feeder connected to the output
terminal of the corresponding matching circuit.
[0119] According to another aspect of the present invention, in an
inspection method of a plasma processing system comprising a
plurality of plasma processing apparatuses, each plasma processing
apparatus comprises a plasma processing chamber having a plasma
excitation electrode for exciting a plasma, a radiofrequency
generator for supplying a radiofrequency voltage to the plasma
excitation electrode, a radiofrequency feeder connected to the
plasma excitation electrode, and a matching circuit having an input
terminal and an output terminal, wherein the input terminal is
connected to the radiofrequency generator via a radiofrequency feed
line, and whereas the output terminal is connected to the
radiofrequency feeder so as to achieve impedance matching between
the plasma processing chamber and the radiofrequency generator.
Further wherein a variation, defined by
(A.sub.max-A.sub.min)/(A.sub.max+A.sub.mi- n), between the maximum
frequency A.sub.max and the minimum frequency A.sub.min among
radiofrequency characteristics A of the plurality of plasma
processing chambers has a predetermined value, and wherein, in each
plasma processing chamber, the radiofrequency characteristic A
thereof is measured at a measuring point which is the
radiofrequency-generator-side end of the radiofrequency feed line
connected to the respective radiofrequency generator.
[0120] According to another aspect of the present invention, in an
inspection method of a plasma processing system comprising a
plurality of plasma processing apparatuses, each plasma processing
apparatus comprises a plasma processing chamber having a plasma
excitation electrode for exciting a plasma, a radiofrequency
generator for supplying a radiofrequency voltage to the plasma
excitation electrode, a radiofrequency feeder connected to the
plasma excitation electrode, and a matching circuit having an input
terminal and an output terminal, wherein the input terminal is
connected to the radiofrequency generator via a radiofrequency feed
line, and whereas the output terminal is connected to the
radiofrequency feeder so as to achieve impedance matching between
the plasma processing chamber and the radiofrequency generator.
Further wherein a variation, defined by
(A.sub.max-A.sub.min)/(A.sub.max+A.sub.mi- n) , between the maximum
frequency A.sub.max and the minimum frequency A.sub.min among
radiofrequency characteristics A of the plurality of plasma
processing chambers has a predetermined value, and wherein, in each
plasma processing chamber, the radiofrequency characteristic A
thereof is measured at a measuring point which is the input
terminal connected to the corresponding radiofrequency feed
line.
[0121] In the present invention, the variation between the maximum
frequency A.sub.max and the minimum frequency A.sub.min among
radiofrequency characteristics A of the plurality of plasma
processing chambers is defined by relationship (10A):
(A.sub.max-A.sub.min)/(A.sub.max+A.sub.min) (10A)
[0122] wherein, in each plasma processing chamber, the
radiofrequency characteristic A thereof is measured at the
measuring point which is at the end of the corresponding
radiofrequency feeder connected to the output terminal of the
corresponding matching circuit. Since this variation has a
predetermined value, there is no variation in radiofrequency
electrical characteristics, such as impedance and resonant
frequency characteristics, between the plasma chambers (plasma
processing chamber units). Thus, the impedance and resonant
frequency characteristics of the plasma chambers can be controlled
so as to be within predetermined range. Accordingly, these
individual plasma chambers consume substantially the same
electrical energy in the corresponding plasma spaces.
[0123] Accordingly, substantially the same result is achieved from
a single process recipe for these different plasma chambers. When
films are formed in these plasma chambers, these films can have
substantially the same characteristics (e.g., the same thickness,
isolation voltage, and etching rate).
[0124] Instead of the above measuring point, the radiofrequency
characteristic A of each plasma processing chamber may also be
measured at a measuring point which is the
radiofrequency-generator-side end of the radiofrequency feed line
connected to the respective radiofrequency generator. These plasma
chambers, including plasma processing chambers and matching
circuits, have substantially the same radiofrequency electrical
characteristics. Thus, these individual plasma chambers consume
substantially the same electrical energy in the corresponding
plasma spaces. Accordingly, substantially the same result is more
effectively achieved from a single process recipe for these
different plasma chambers as compared to a method that does not
include a matching circuit in the range to be measured.
[0125] Instead of the above measuring point, the radiofrequency
characteristic A thereof may also be measured at a measuring point
which is the input terminal connected to the corresponding
radiofrequency feeder. These plasma chambers, including matching
circuits and radiofrequency feeders, have substantially the same
radiofrequency electrical characteristics. Thus, these individual
plasma chambers consume substantially the same electrical energy in
the corresponding plasma spaces. Accordingly, substantially the
same result is further effectively achieved from a single process
recipe for these different plasma chambers as compared to a method
that does not include a matching circuit and a radiofrequency
feeder in the range to be measured.
[0126] When the predetermined value is less than 0.1, the variation
in thicknesses of films which are deposited under substantially the
same conditions in different chambers can be controlled to be
within .+-.5%, resulting in uniform plasma processing.
[0127] When the predetermined value is less than 0.03, these plasma
chambers have substantially the same radiofrequency electrical
characteristics (e.g., impedance and resonant frequency
characteristics). Thus, the impedance characteristics of these
plasma chambers can be controlled to be in a predetermined range so
that these plasma chambers have substantially the same electrical
energy in the plasma spaces.
[0128] Accordingly, substantially the same result is achieved from
a single process recipe for these different plasma chambers. When
films are formed in these plasma chambers, these films can have
substantially the same characteristics (e.g., the same thickness,
isolation voltage, and etching rate). When the predetermined value
is less than 0.03, the variation in thicknesses of films which are
deposited under substantially the same conditions in different
chambers can be controlled to be within .+-.2%.
[0129] In the present invention, one of the resonant frequency f,
the impedance Z.sub.e, the resistance R.sub.e, and the reactance
X.sub.e at the frequency of the radiofrequency waves is employed as
the radiofrequency characteristic A so that the different plasma
chambers have substantially the same radiofrequency electrical
characteristics. Since these plasma chambers can be operated under
conditions within the predetermined ranges using impedance
characteristics as references, these plasma chambers consume
substantially the same electrical energy in the plasma spaces
thereof.
[0130] The resonant frequency f is determined by measuring the
dependence of the impedance Z on the frequency. In contrast, the
impedance Z.sub.e at the frequency for exciting the plasma can be
readily determined without determining the dependence of the
radiofrequency characteristics of the plasma chamber on the
frequency. Moreover, the impedance Z.sub.e more directly reflects
the radiofrequency electrical characteristics of the plasma chamber
at the plasma excitation frequency.
[0131] When the resistance R.sub.e or the reactance X.sub.e is
employed, this can more directly reflect the radiofrequency
electrical characteristic at the plasma excitation frequency of the
plasma chamber as compared with the impedance Z.sub.e, which
corresponds to the vector defined by the resistance R.sub.e and the
reactance X.sub.e.
[0132] The radiofrequency characteristic A may be the first series
resonant frequency f.sub.0.
[0133] The first series resonant frequency f.sub.0 is a
radiofrequency electrical characteristic which is determined by
various factors, such as the mechanical structure. Thus, it is
believed that apparatuses in use have different first series
resonant frequencies f.sub.0. In the present invention, the first
series resonant frequency f.sub.0 is set to be within the
above-mentioned predetermined range. Consequently, overall
radiofrequency electrical characteristics of the individual chamber
can be controlled, resulting in the generation of a highly stable
plasma in each plasma chamber. In other words, the operations of
the individual plasma chambers of the plasma processing apparatus
or system are uniform and stable.
[0134] This process does not require a determination of the process
conditions based on the relationship between enormous amounts of
data for the individual plasma chambers and the results obtained by
evaluation of actually processed substrates. Thus, in the
installation of new systems and inspection of installed systems,
the time required for obtaining substantially the same results
using the same process recipe in these plasma chambers can be
significantly reduced as compared with an inspection process by
actual deposition onto the substrates to be processed. Thus, the
production line can reduce the cost of substrates used in the
inspection, processing of these substrates, and labor during the
inspection operations.
[0135] Preferably, three times the first series resonant frequency
f.sub.0 corresponding to each plasma processing chamber is larger
than the frequency f.sub.e of the radiofrequency waves. Thus,
electrical power can be effectively introduced into the plasma
space when the radiofrequency is higher than 13.56 MHz (which is
used in conventional methods). As a result, the deposition rate of
the film is improved.
[0136] In the plasma processing apparatus of the present invention,
each plasma processing chamber preferably has a measuring terminal
for measuring the radiofrequency characteristic A thereof at the
corresponding measuring point. In addition, each plasma processing
chamber preferably has a switch in the vicinity of the
corresponding measuring point in which the switch electrically
disconnects the measuring point from the measuring terminal and
connects the plasma excitation electrode to the radiofrequency
generator in a plasma excitation mode (in which the plasma is
excited), whereas the switch electrically connects the measuring
point to the measuring terminal and disconnects the radiofrequency
generator from the measuring point in a measuring mode in which the
radiofrequency characteristic A of the corresponding plasma
processing chamber is measured. In the measuring mode, the switch
disconnects the measuring terminal from the radiofrequency
generator, the radiofrequency feed line, the matching circuit, the
radiofrequency feeder, or the plasma excitation electrode. Thus, a
probe can be readily connected to the impedance measuring terminal
when the impedance characteristics of each plasma chamber are
measured. Moreover, the switch does not require mechanical
detachment of the obstacle components, such as the radiofrequency
generator, the radiofrequency feed line, the matching circuit, and
the radiofrequency feeder, when the impedance characteristics of
each plasma chamber are measured. Thus, the radiofrequency
characteristic A can be more precisely measured in each plasma
chamber. Moreover, the radiofrequency characteristics A of a
plurality of plasma chambers can be readily measured. Thus, in the
installation of new systems and the inspection of installed
systems, the time required for obtaining substantially the same
results using the same process recipe in these plasma chambers can
be significantly reduced as compared with conventional inspection
process (which requires a monthly period).
[0137] More specifically, each plasma processing chamber has the
measuring terminal for measuring the radiofrequency characteristic
A thereof in the vicinity of an end of the radiofrequency feeder.
In addition, each plasma processing chamber has the switch between
the end of the radiofrequency feeder and the measuring point in
which the switch electrically disconnects the radiofrequency feeder
from the measuring terminal and connects the end of the
radiofrequency feeder to the output terminal of the matching
circuit in a plasma excitation mode (in which the plasma is
excited), whereas the switch electrically connects the end of the
radiofrequency feeder to the measuring terminal and disconnects the
end of the radiofrequency feeder from the output terminal of the
matching circuit in a measuring mode in which the radiofrequency
characteristic A of the plasma processing chamber is measured. In
the measuring mode, the switch disconnects the conductor for
supplying electrical power from the matching circuit. Thus, a probe
can be readily connected to the impedance measuring terminal when
the impedance characteristics of each plasma chamber is measured.
Since the matching circuit is disconnected by the switch, the
impedance characteristics of the plasma chamber can be more exactly
measured via the switch. Thus, the first series resonant
frequencies f.sub.0 of a plurality of plasma chambers can be
readily measured. In the installation of new systems and the
inspection of installed systems, the time required for obtaining
substantially the same results using the same process recipe in
these plasma chambers can be significantly reduced as compared with
conventional inspection process (which requires a monthly
period).
[0138] Since the impedance meter is detachable in the present
invention, the impedance meter is detached from the measuring
terminal or disconnected from the measuring terminal by a switch in
the plasma excitation mode. Thus, the impedance meter is not
electrically affected in the plasma excitation mode. The
radiofrequency characteristics A, and particularly first series
resonant frequencies f.sub.0 of these plasma chambers, can be
readily measured by measuring the impedance or the like by
operating the switch without disconnecting the impedance meter from
the plasma chambers.
[0139] The connection may be sequentially switched to the measuring
terminals of these plasma chambers to measure the radiofrequency
characteristics of these plasma chambers using a single impedance
meter.
[0140] Using the above switch, the radiofrequency characteristic A
measured at the radiofrequency generator side when the measuring
point is electrically disconnected from the measuring terminal
while the radiofrequency feeder is electrically connected to the
radiofrequency generator is preferably equalized to the
radiofrequency characteristic A measured at the measuring terminal
side when the measuring point is electrically connected to the
measuring terminal while the radiofrequency generator is
electrically disconnected from the measuring point. More
specifically, using the above switch, the radiofrequency
characteristic A at the output end of the matching circuit when an
end of the radiofrequency feeder is electrically disconnected from
the measuring terminal while the end of the radiofrequency feeder
is electrically connected to the output end of the matching circuit
may be equalized to the radiofrequency characteristic A at the
measuring terminal when the end of the radiofrequency feeder is
electrically connected to the measuring terminal while the end of
the radiofrequency feeder is electrically disconnected from the
output end of the matching circuit. More specifically, the
radiofrequency characteristic A at the output terminal of the
matching circuit when an end of the radiofrequency feeder is
electrically disconnected from the measuring terminal while the end
of the radiofrequency feeder is electrically connected to the
output terminal of the matching circuit may be equalized to the
radiofrequency characteristic A at the measuring terminal when the
end of the radiofrequency feeder is electrically connected to the
measuring terminal while the end of the radiofrequency feeder is
electrically disconnected from the output terminal of the matching
circuit. Thus, the values such as impedance measured with the
impedance meter, which is connected to the measuring terminals of
the plasma chambers, include the same correction factor from the
measuring points. Thus, the observed radiofrequency characteristics
A, such as the first series resonant frequency, can be used without
correction, resulting in improved operation efficiency.
[0141] The above-mentioned means may be performed as follows. The
radiofrequency characteristic A between the measuring point and the
impedance meter connected to the measuring terminal is set to be
identical to each other in the plasma processing chamber units
(plasma chambers). More specifically, the length of the coaxial
cable from the output position of the final stage at the output
side of the matching circuit to the impedance meter is equal in
each of these units.
[0142] The number of the plasma chambers provided in each plasma
processing apparatus, the number of the plasma processing
apparatuses in each plasma processing system, and the number of the
plasma chambers may be appropriately determined in the present
invention.
[0143] If these plasma processing apparatuses are used by different
process recipes, the radiofrequency characteristics A, such as
first series resonant frequency f.sub.0, may be determined for each
plasma processing apparatus in the same plasma processing
system.
[0144] In the present invention, the plasma enhanced CVD unit may
be of a dual-frequency excitation type which has a first
radiofrequency generator, a radiofrequency electrode connected to
the first radiofrequency generator, a radiofrequency electrode side
matching box having a matching circuit for impedance matching
between the first radiofrequency generator and the radiofrequency
electrode, a second radiofrequency generator, a susceptor electrode
which opposes the radiofrequency electrode, which is connected to
the second radiofrequency generator, and supports a substrate to be
treated, and a susceptor side matching box having a matching
circuit for impedance matching between the second radiofrequency
generator and the susceptor electrode. The frequency of the
radiofrequency waves and the radiofrequency characteristics A, such
as first series resonant frequency f.sub.0, which are measured at
the output terminal of the matching circuit at the susceptor side,
may be determined as in the cathode electrode side.
[0145] In the performance validation system for the plasma
processing apparatus or the plasma processing system of the present
invention, a maintenance engineer uploads performance information
that shows the status of the operational performance of each plasma
processing apparatus purchased by a customer. The customer can
obtain the standard performance information, which is useful for
determining the purchase of the apparatus or system, and the
operation and maintenance information, including radiofrequency
characteristics A, such as first series resonant frequency f.sub.0,
of the apparatus or system in use with his terminal via a public
line. The performance information can also be generated in the form
of a catalog or specification documents.
[0146] In the inspection method of the plasma processing apparatus
or system, a variation between the maximum frequency A.sub.max and
the minimum frequency A.sub.min among radiofrequency
characteristics A of the plurality of plasma processing chambers of
the apparatus of system is defined by the relationship (10A):
(A.sub.max-A.sub.min)/(A.sub.max+A.sub.min) (10A)
[0147] By checking whether the variation lies within a
predetermined value, it can be confirmed that these plasma chambers
are set to have substantially the same radiofrequency electrical
characteristics, such as impedance and resonant frequency
characteristics. Since the impedance characteristics and the like
of these plasma chambers can be controlled within a predetermined
range, these plasma chambers consume substantially the same
electrical power in the plasma space and generate substantially the
same plasma density.
[0148] Accordingly, substantially the same result is achieved from
a single process recipe for these different plasma chambers. When
films are formed in these plasma chambers, these films can have
substantially the same characteristics (e.g., the same thickness,
isolation voltage, and etching rate).
[0149] The radiofrequency electrical characteristics of each plasma
chamber are determined by the size and the shape thereof. Since
each component constituting the plasma chamber has a variation in
size due to the machining tolerance that is inevitable in the
mechanical processing for the chamber production. In addition, each
plasma chamber has an assembling tolerance. Moreover, the plasma
chamber includes portions in which sizes thereof are not measured
after assembling. This inspection method, however, quantitatively
determines the performance of plasma chambers regardless of the
unmeasurable portions and differences in radiofrequency electrical
characteristics between these chambers.
[0150] Alternatively, in each plasma processing chamber unit, the
radiofrequency characteristic A thereof is measured at a measuring
point which is the radiofrequency-generator-side end of the
radiofrequency feed line connected to the respective radiofrequency
generator. In this case, differences in radiofrequency electrical
characteristics between a plurality of plasma chambers including
matching circuits are set to be substantially zero. Thus, these
plasma chambers consume substantially the same electrical power in
the plasma spaces. Accordingly, substantially the same result is
more readily achieved from a single process recipe for these
different plasma chambers as compared with a case in which the
matching circuit is not included in the measuring range.
[0151] Alternatively, in each plasma processing chamber unit, the
radiofrequency characteristic A thereof is measured at a measuring
point which is the input terminal connected to the corresponding
radiofrequency feed line. In this case, differences in
radiofrequency electrical characteristics between a plurality of
plasma chambers including matching circuits and radiofrequency feed
lines are set to be substantially zero. Thus, the electrical power
consumption in the plasma spaces of these plasma chambers becomes
uniform. Accordingly, substantially the same result is more readily
achieved from a single process recipe for these different plasma
chambers as compared with a case in which the matching circuit and
the radiofrequency feed line is included in the measuring
range.
[0152] By confirming that the variation is set to be less than 0.1
in this inspection method, it can be confirmed that the plasma
processing is uniform. For example, whether the thickness of the
film which is deposited in each plasma chamber under substantially
the same conditions is controlled to be within .+-.5%.
[0153] By confirming that the variation is set to be less than 0.03
in this inspection method, a plurality of plasma chambers are set
to have substantially the same radiofrequency electrical
characteristics (such as impedance and resonant frequency
characteristics). Thus, it can be confirmed that the impedance
characteristics are controlled to be within a predetermined range.
Thus, the density of the plasma generated in each plasma chamber
becomes uniform.
[0154] Accordingly, the plasma chambers can be controlled as
follows. Substantially the same result is achieved from a single
process recipe for these different plasma chambers. When films are
formed in these plasma chambers, these films can have substantially
the same characteristics (e.g., the same thickness, isolation
voltage, and etching rate. When the variation is controlled to be
less than 0.03 under the same deposition conditions in the plasma
chambers, the variation in film thickness can be controlled to be
less than .+-.2%.
[0155] In the inspection method of the plasma processing apparatus
or system, as described above, each radiofrequency characteristic A
may be any one of a resonant frequency f, an impedance Z.sub.e at
the frequency of the radiofrequency generator, a resistance R.sub.e
at the frequency of the radiofrequency generator, and a reactance
X.sub.e at the frequency of the radiofrequency generator. Thus, the
impedance characteristics, such as impedance of a plurality of
plasma chambers, are controlled to be within a predetermined range,
and the effective electric energies consumed in the plasma spaces
are set to be substantially equal.
[0156] When the impedance Z.sub.e at the frequency of the
radiofrequency generator is employed as the radiofrequency
characteristic A, it is not necessary to find the dependence of the
radiofrequency characteristic on the frequency in the plasma
chambers. Thus, the impedance Z.sub.e at the frequency of the
radiofrequency generator can be readily determined as compared with
the resonant frequency f, which must be determined by the
dependence of the impedance Z on the frequency. Moreover, the
impedance Z.sub.e can directly reflect the radiofrequency
electrical characteristic at the plasma excitation frequency of the
plasma chambers.
[0157] When the resistance R.sub.e or the reactance X.sub.e is
employed, this can more directly reflect the radiofrequency
electrical characteristic at the plasma excitation frequency of the
plasma chamber as compared with the impedance Z.sub.e, which
corresponds to the vector defined by the resistance R.sub.e and the
reactance X.sub.e.
[0158] The connection can be sequentially switched to the measuring
terminals of these plasma chambers to measure the radiofrequency
characteristics of these plasma chambers using a single impedance
meter.
[0159] Using the above switch, the radiofrequency characteristic A
measured at the radiofrequency generator side when the measuring
point is electrically disconnected from the measuring terminal
while the radiofrequency feeder is electrically connected to the
radiofrequency generator is equalized to the radiofrequency
characteristic A measured at the measuring terminal side when the
measuring point is electrically connected to the measuring terminal
while the radiofrequency generator is electrically disconnected
from the measuring point. Thus, the values such as the impedance
measured with the impedance meter, which is connected to the
measuring terminals of the plasma chambers, include the same
correction factor from the measuring points. Thus, the observed
radiofrequency characteristics A, such as the first series resonant
frequency, can be used without correction, resulting in improved
operation efficiency.
BRIEF DESCRIPTION OF THE DRAWINGS
[0160] FIG. 1 is an outline schematic view of a plasma processing
apparatus in accordance with a first embodiment of the present
invention;
[0161] FIG. 2 is a schematic view of a matching circuit of the
plasma processing apparatus shown in FIG. 1;
[0162] FIG. 3 is a schematic view for illustrating impedance
characteristics of the plasma processing apparatus of the first
embodiment;
[0163] FIG. 4 is an equivalent circuit diagram of the plasma
processing apparatus shown in FIG. 3;
[0164] FIG. 5 is a graph illustrating the dependence of the
impedance Z and the phase .theta. on the frequency for defining a
first series resonant frequency f.sub.0;
[0165] FIG. 6 is a graph illustrating the dependence of the
impedance Z and the phase .theta. on the frequency for defining a
first series resonant frequency f.sub.0 in the first embodiment of
the plasma processing apparatus;
[0166] FIG. 7 is an outline schematic view of a plasma processing
apparatus in accordance with a second embodiment of the present
invention;
[0167] FIG. 8 is a schematic view for illustrating impedance
characteristics of the plasma processing apparatus of the second
embodiment;
[0168] FIG. 9 is an equivalent circuit diagram of the plasma
processing apparatus shown in FIG. 8;
[0169] FIG. 10 is a graph illustrating the dependence of the
impedance Z and the phase .theta. on the frequency for defining a
first series resonant frequency f.sub.0 in the second embodiment of
the plasma processing apparatus;
[0170] FIG. 11 is an outline schematic view of a plasma processing
apparatus in accordance with a third embodiment of the present
invention;
[0171] FIG. 12 is an equivalent circuit diagram of the plasma
processing apparatus shown in FIG. 11;
[0172] FIG. 13 is a graph illustrating the dependence of the
impedance Z and the phase .theta. on the frequency for defining a
first series resonant frequency f.sub.0 in the third embodiment of
the plasma processing apparatus;
[0173] FIG. 14 is a schematic view of a plasma emission state
between electrodes;
[0174] FIG. 15 is an equivalent circuit diagram of an embodiment of
the plasma processing apparatus in accordance with the present
invention;
[0175] FIG. 16 is an isometric view of a probe for an impedance
meter;
[0176] FIG. 17 is a schematic view illustrating connection of the
probe for the impedance meter shown in FIG. 16;
[0177] FIG. 18 is a schematic view of an exemplary conventional
plasma processing apparatus;
[0178] FIG. 19 is a schematic view of another conventional plasma
processing apparatus;
[0179] FIG. 20 is a schematic view illustrating a performance
validation system of the plasma processing apparatus in accordance
with the present invention;
[0180] FIG. 21 is a flow chart illustrating a process for providing
performance information from a server S in the performance
validation system of the plasma processing apparatus of the present
invention;
[0181] FIG. 22 shows an output form of a main page CP in accordance
with the performance validation system of the plasma processing
apparatus of the present invention;
[0182] FIG. 23 shows an output form of a subpage CP1 in accordance
with the performance validation system of the plasma processing
apparatus of the present invention;
[0183] FIG. 24 shows an output form of a main page CP2 in
accordance with the performance validation system of the plasma
processing apparatus of the present invention;
[0184] FIG. 25 shows an output form of a subpage CP3 in accordance
with the performance validation system of the plasma processing
apparatus of the present invention;
[0185] FIG. 26 is an outline schematic view of a plasma processing
apparatus in accordance with a fourth embodiment of the present
invention;
[0186] FIG. 27 is a cross-sectional view of the laser annealing
chamber shown in FIG. 26;
[0187] FIG. 28 is a cross-sectional view of the annealing chamber
shown in FIG. 26;
[0188] FIG. 29 is an outline schematic view of a plasma processing
apparatus in accordance with a fifth embodiment of the present
invention;
[0189] FIG. 30 is an equivalent circuit diagram of the plasma
processing apparatus shown in FIG. 11;
[0190] FIG. 31 is an outline schematic view of a plasma processing
system in accordance with a sixth embodiment of the present
invention;
[0191] FIG. 32 is an outline schematic view of another embodiment
of the plasma processing apparatus in accordance with the present
invention;
[0192] FIG. 33 is an outline schematic view of another embodiment
of the plasma processing apparatus in accordance with the present
invention;
[0193] FIG. 34 is an outline schematic view of another embodiment
of the plasma processing apparatus in accordance with the present
invention;
[0194] FIG. 35 is an outline schematic view of a plasma processing
unit (plasma chamber) of a plasma processing system in accordance
with a seventh embodiment of the present invention;
[0195] FIG. 36 is a schematic view for illustrating impedance
characteristics of the plasma chamber shown in FIG. 35;
[0196] FIG. 37 is an equivalent circuit diagram for measuring
impedance characteristics of the plasma chamber shown in FIG.
36;
[0197] FIG. 38 shows an output form of a subpage CP3 in accordance
with the performance validation system of the plasma processing
apparatus of the present invention;
[0198] FIG. 39 shows an output form of a subpage CP4 in accordance
with the performance validation system of the plasma processing
apparatus of the present invention; and
[0199] FIG. 40 is an outline schematic view of another plasma
processing apparatus in accordance with a seventh embodiment of the
present invention; and
[0200] FIG. 41 is an outline schematic view of another plasma
processing apparatus in accordance with a seventh embodiment of the
present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0201] First Embodiment
[0202] A plasma processing apparatus according to a first
embodiment of the present invention will now be described with
reference to the drawings.
[0203] FIG. 1 is a cross-sectional view schematically illustrating
the structure of a plasma processing apparatus of the first
embodiment. FIG. 2 illustrates a matching circuit of the plasma
processing apparatus shown in FIG. 1.
[0204] The plasma processing apparatus of this embodiment is of a
single-frequency excitation type and performs plasma processing
such as chemical vapor deposition (CVD), sputtering, dry etching,
ashing, or the like. Referring to FIG. 1, the plasma processing
apparatus comprises a plasma chamber (plasma processing chamber) CN
having parallel plate type electrodes 4 and 8 for exciting a
plasma, a radiofrequency generator 1 connected to the electrode 4,
and a matching circuit 2A for matching the impedance between the
plasma chamber CN and the radiofrequency generator 1.
[0205] In the plasma processing apparatus of this embodiment, it is
arranged that three times the first series resonant frequency
f.sub.0 of the plasma chamber CN measured at an output position PR
of the matching circuit 2A is larger than the power frequency
f.sub.e fed from the radiofrequency generator 1 to the plasma
chamber CN, as described below.
[0206] To be more specific, as shown in FIGS. 1 and 2, in the
plasma processing apparatus of this embodiment, the plasma
excitation electrode 4, which is connected to the radiofrequency
generator 1, and a shower plate 5 are disposed in the upper portion
of the plasma chamber CN. The electrode 8 serving as a susceptor
electrode for receiving a substrate 16 is provided facing the
shower plate 5 in the lower portion of the plasma chamber CN. The
plasma excitation electrode 4 is connected to the radiofrequency
generator 1 via a feed plate (radiofrequency feeder) 3 and the
matching circuit 2A. The plasma excitation electrode 4 and the feed
plate 3 are covered by a chassis 21. The matching circuit 2A is
accommodated inside a matching box 2 composed of a conductor.
[0207] A silver-plated copper plate 50 to 100 mm in width, 0.5 mm
in thickness, and 100 to 300 mm in length is used as the feed plate
3. The feed plate 3 is screwed to an output end of a tuning
capacitor 24 of the matching circuit 2A (described below) and the
plasma excitation electrode 4.
[0208] At the lower side of the plasma excitation electrode 4
functioning as the cathode, a projection 4a is provided. The
projection 4a is in contact with the shower plate 5 provided below
the plasma excitation electrode 4. The plasma excitation electrode
4 and the shower plate 5 define a space 6. A gas feeding tube 17 is
connected to the space 6, and an insulator 17a is inserted midway
in the gas feeding tube 17 so as to insulate the plasma excitation
electrode 4 from the gas supply.
[0209] The gas from the gas feeding tube 17 is fed to a chamber
space 60, formed by a chamber wall 10, through a number of holes 7
in the shower plate 5. The chamber wall 10 and the plasma
excitation electrode 4 are isolated from each other by an insulator
9. The exhaust system is omitted from the drawing.
[0210] The susceptor electrode 8 (wafer susceptor) which receives
the substrate 16 and also serves as a plasma excitation electrode
is provided in the chamber space 60.
[0211] A shaft 13 is joined to the susceptor electrode 8 at the
bottom center of the susceptor electrode 8, and penetrates a
chamber bottom 10A. The lower portion of the shaft 13 and the
center portion of the chamber bottom 10A are hermetically connected
by a bellows 11. The bellows 11 allows the susceptor electrode 8
and the shaft 13 to move upward and downward so as to control the
distance between the electrodes 4 and 8.
[0212] Because the susceptor electrode 8, the shaft 13, and a
supporting tube 12B are connected, the susceptor electrode 8, the
shaft 13, the bellows 11, the chamber bottom 10A, and the chamber
wall have the same DC potential. Moreover, because the chamber wall
10 and the chassis 21 are connected, the chamber wall 10, the
chassis 21, and the matching box 2 also have the same DC
potential.
[0213] The matching circuit 2A is generally constituted from a
plurality of passive devices in order to adjust the impedance in
response to changes in the state of the plasma inside the plasma
chamber.
[0214] Referring to FIGS. 1 and 2, a coil 23 and the tuning
capacitor 24, as the passive devices, are provided in the matching
circuit 2A in series between the radiofrequency generator 1 and the
feed plate 3. A load capacitor 22 is connected in parallel to the
coil 23 and the tuning capacitor 24. One end of the load capacitor
22 is connected to the matching box 2. The tuning capacitor 24 is
connected to the plasma excitation electrode 4 via the feed plate
3.
[0215] The matching box 2 is connected to a shielding line of a
feed line 1A that is a coaxial cable, and this shielding line is DC
grounded. In this manner, the susceptor electrode 8, the shaft 13,
the bellows 11, the chamber bottom 10A, the chamber wall 10, the
chassis 21, and the matching box 2 are set to a ground voltage
while one end of the load capacitor 22 is DC-grounded.
[0216] In this embodiment, power with a frequency of 13.56 MHz or
more, and more specifically, power with a frequency of 13.56 MHz,
27.12 MHz, or 40.68 MHz is used to generate a plasma between the
electrodes 4 and 8. Using this plasma, the substrate 16 placed on
the susceptor electrode 8 is subjected to a plasma process such as
CVD, dry etching, ashing, or the like.
[0217] At this stage, the radiofrequency voltage is supplied from
the radiofrequency generator 1 to the coaxial cable of the feed
line 1A, the matching circuit 2A, the feed plate 3, and the plasma
excitation electrode 4 (cathode electrode). As for the path of the
radiofrequency current, the current flows into the plasma space
(chamber space 60) via the above-described components, then to the
susceptor electrode 8, the shaft 13, the bellows 11, the chamber
bottom 10A and the chamber wall 10, and finally into the chassis
21, the matching box 2, and the shielding line of the feed line 1A,
back to the earth of the radiofrequency generator 1.
[0218] Now, the first series resonant frequency f.sub.0 of the
plasma processing apparatus of this embodiment will be
described.
[0219] The first series resonant frequency f.sub.0 is the least
significant frequency among the frequencies assigned to the minima
of the impedance Z when the dependency between the impedance and
the frequency in the plasma chamber CN is measured. The first
series resonant frequency f.sub.0 is set larger than the power
frequency f.sub.e described above.
[0220] The first series resonant frequency is an electrical
radiofrequency property mainly determined by the mechanical
structure and is measured as shown in FIGS. 3 and 4.
[0221] FIG. 3 is an illustration for explaining the impedance
property of the plasma processing apparatus, and FIG. 4 is an
equivalent circuit diagram of the circuit shown in FIG. 3.
[0222] The region of the plasma chamber CN to be measured is the
region of the plasma chamber CN without the matching circuit 2A,
the matching circuit 2A being detached from the plasma chamber CN
at an output end position of a passive device which is the final
output stage among the passive devices of the matching circuit 2A.
More particularly, the matching circuit is removed from the plasma
chamber CN by removing the screws clamping the feed plate 3 and the
matching circuit 2A at the output end position PR of the tuning
capacitor 24 connected to the feed plate 3 as shown in FIG. 3, and
the remaining part of the plasma chamber CN is the measured
region.
[0223] As shown by broken lines in FIG. 3, a probe 105 of an
impedance meter AN is connected to the output end position PR at
which separation was carried out and to an earth position such as
the chassis 21 of the plasma chamber CN. In this state, a,measuring
frequency oscillated by the impedance meter AN is varied over the
range of 1 MHz to 100 MHz so as to determine the vector quantity
(Z, .theta.) of the impedance of the above-described measured
region of the plasma chamber CN.
[0224] As shown in FIG. 3, the probe 105 comprises a conductive
line 110, an insulation coating 112 provided on the conductive line
110, and a peripheral conductor 111 covering the insulation coating
112. The probe 105 is connected to the impedance meter (resonant
frequency meter) AN via a coaxial cable.
[0225] Next, as shown in FIG. 5, the impedance Z and phase .theta.
(deg) are plotted along the ordinates of the graph having the
abscissa indicating measuring frequency f (MHz). In the graph, the
ordinate at the left side corresponds to impedance Z (.OMEGA.) and
the ordinate at the right side corresponds to phase .theta.
(degree). Referring to the impedance characteristic curve (shown by
a solid line) and the phase curve (shown by a broken line) in FIG.
5, the first series resonant frequency f.sub.0 is defined as the
frequency corresponding to the minimum value Z.sub.min of the
impedance, i.e., the frequency assigned to a phase .theta. of zero
when the phase .theta. first goes from positive to negative while
the measuring frequency f is increased.
[0226] In the thus determined first series resonant frequency
f.sub.0, the following electrical radiofrequency factors within the
above-described measured region are taken into a consideration, as
shown in FIG. 3:
[0227] Inductance L.sub.f and resistance R.sub.f of the feed plate
3;
[0228] Plasma electrode capacitance C.sub.e between the plasma
excitation electrode 4 and the susceptor electrode 8;
[0229] Inductance L.sub.C and resistance R.sub.C of the shaft
13;
[0230] Inductance L.sub.B and resistance R.sub.B of the bellows
11;
[0231] Inductance L.sub.A and resistance R.sub.A of the chamber
wall 10;
[0232] Capacitance C.sub.A between the gas feeding tube 17 and the
plasma excitation electrode 4 via the insulator 17a;
[0233] Capacitance C.sub.B between the plasma excitation electrode
4 and the chassis 21; and
[0234] Capacitance C.sub.C between the plasma excitation electrode
4 and the chamber wall 10.
[0235] These electrical radiofrequency factors are arranged in the
same manner as in the circuit for generating plasma using
radiofrequency current so as to form an equivalent circuit shown in
FIG. 4. More specifically, the inductance L.sub.f and resistance
R.sub.f of the feed plate 3, the plasma electrode capacitance
C.sub.e between the plasma excitation electrode 4 and the susceptor
electrode 8, the inductance L.sub.C and resistance R.sub.C of the
shaft 13, the inductance L.sub.B and resistance R.sub.B the bellows
11, and the inductance L.sub.A and resistance R.sub.A of the
chamber wall 10 are connected in series in that order while having
the resistance R.sub.A grounded. Between the resistance R.sub.f and
the plasma electrode capacitance C.sub.e, the capacitance C.sub.A,
the capacitance C.sub.B, and the capacitance C.sub.C are connected
in parallel, one end of each being grounded. By determining the
impedance characteristics of this equivalent circuit, the first
series resonant frequency f.sub.0 of this embodiment can be
defined.
[0236] The first series resonant frequency f.sub.0 is adjusted so
that three times f.sub.0 is larger than the power frequency f.sub.e
supplied from the radiofrequency generator 1.
[0237] Examples of the methods for adjusting the first series
resonant frequency f.sub.0 are as follows:
[0238] (1) Adjusting the shape (length) of the feed plate 3;
[0239] (2) Adjusting the overlapping area of the plasma excitation
electrode 4 and the chamber wall 10;
[0240] (3) Adjusting the insulating material between the plasma
excitation electrode 4 and the chamber wall 10; and
[0241] (4) Connecting the susceptor electrode 8 and the chamber
wall 10 with a conductor.
[0242] For example, in the plasma processing apparatus of this
embodiment, the power frequency f.sub.e is set to 40.68 MHz and the
impedance Z (.OMEGA.) and the phase .theta. (deg) relative to the
measurement frequency f (MHz) ranging from 0 to 100 MHz are
measured to form an impedance characteristic curve and a phase
curve, as shown in FIG. 6. The first series resonant frequency
f.sub.0 is then set to 16.5 MHz so that relationship (2) below is
satisfied.
3f.sub.0>f.sub.e (2)
[0243] In the plasma processing apparatus of this embodiment, the
first series resonant frequency f.sub.0 is adjusted so that three
times f.sub.0 is larger than the power frequency f.sub.e supplied
from the radiofrequency generator 1, as described above. In this
manner, the overall radiofrequency electrical characteristics of
the plasma chamber CN, which are not considered in the conventional
process, can be optimized. Also, the operational stability is
improved thereby, and it becomes possible to efficiently deliver
power from the radiofrequency generator 1 to the plasma generation
space between the plasma excitation electrode 4 and the susceptor
electrode 8 even when a radiofrequency voltage exceeding the
conventionally used frequency, i.e., 13.56 MHz, is used. Moreover,
when the same frequency as in the conventional process is supplied,
the effective power consumed in the plasma space can be increased
and the density of the generated plasma can be improved as compared
to the conventional plasma processing apparatuses. As a result, the
processing rate can be improved by increasing the plasma excitation
frequency. In other words, the deposition rate can be improved in
the plasma-enhanced CVD process or the like.
[0244] Because the power can be efficiently supplied to the plasma
space, undesirable spreading of the plasma can be inhibited, and
the uniformity in plasma processing in the planar direction of the
substrate 16 can be improved, thereby improving the
planar-direction distribution of the layer thickness during the
layer deposition.
[0245] When the radiofrequency power is supplied, the potential of
the plasma can be reduced and damage due to ions can be prevented.
As a consequence, the state of deposition, i.e., the layer
characteristics such as isolation voltage, etching resistance,
density of the deposited layer (hardness of the layer), or the
like, can be improved during deposition processes such as
plasma-enhanced CVD processes, sputtering processes, and the
like.
[0246] Note that the density of the deposited layer can be
expressed as the etching resistance, which indicates the resistance
against etching using a BHF solution.
[0247] Furthermore, even when power having the same frequency as
the conventional apparatus is supplied, the power can be supplied
to the plasma space with an improved efficiency as compared to the
conventional apparatus. Because of such an improvement in the power
consumption efficiency, the power required for obtaining the same
processing rate and the same layer characteristics as the
conventional process can be reduced. Since the power consumption is
reduced, the operating costs can also be reduced. If the power is
supplied for the same period of time, then the production can be
increased due to a reduced processing time. In all of these cases,
power can be saved and the total emission of carbon dioxide due to
power consumption can be reduced.
[0248] The first series resonant frequency f.sub.0 can be measured
in situ using an impedance meter AN. Accordingly, the performance
validation and evaluation of the plasma processing apparatus can be
completed in a shorter period of time. There is no need to stop the
manufacturing line for several days or several weeks to wait for
the results of the performance validation and evaluation carried
out by inspecting the deposited substrate. Thus, the productivity
of the manufacturing line can be improved.
[0249] Since the first series resonant frequency f.sub.0 is mainly
determined by the factors relating to the mechanical structure
thereof, the first series resonant frequency f.sub.0 differs
according to specific apparatuses. By setting the first series
resonant frequency f.sub.0 of each apparatus to the above-described
range, it becomes possible to provide each of the apparatuses with
predetermined overall radiofrequency electrical characteristics and
to achieve stable plasma generation. As a consequence, a plasma
processing apparatus with an improved operational stability can be
provided.
[0250] Alternatively, as shown in FIG. 16, a fixture comprising a
plurality of conductive wires 101a to 101h, each having a matching
impedance, and a probe attachment 104, to which one end of each of
the plurality of conductive wires 101a to 101h is attached, may be
used to measure the impedance characteristics of the plasma chamber
CN.
[0251] The probe attachment 104 is formed, for example, by shaping
a 50 mm.times.10 mm.times.0.5 mm copper plate to have a clamping
portion 106 and a ring portion. The diameter of the ring portion is
determined so that the ring portion is attachable to the
circumference of the probe 105. The conductive wires 101a to 101h
are soldered to the probe attachment 104 to be electrically
connected thereto.
[0252] Terminals (attachments) 102a to 102h, which are attachable
to and detachable from a measuring object, are installed at the
other ends of the conductive wires 101a to 101h, respectively.
[0253] When this fixture is used, the probe 105 is inserted into
the ring portion of the probe attachment 104, and the probe 105 and
the probe attachment 104 are clamped by the clamping portion 106.
The conductive wires 101a to 101h are detachably screwed to the
measuring object in a substantially symmetrical manner about a
point through the terminals 102a to 102h, as shown in FIG. 17.
[0254] The conductive wires 101a to 101h may be made of, for
example, aluminum, copper, silver, or gold, or may be plated by
silver or gold having a thickness of 50 .mu.m or more.
[0255] The method for measuring impedance using this fixture is now
explained with reference to FIG. 17.
[0256] First, the radiofrequency generator 1 and the matching box 2
are removed from the plasma processing apparatus. The conductive
line 110 of the probe 105 of an impedance meter is then connected
to the feed plate 3. The terminals 102a to 102h connected to the
conductive wires 101a to 101h of the fixture of the impedance meter
are screwed to the chassis 21 of the plasma processing apparatus in
a symmetrical manner about the feed plate 3 using screws 114. After
the impedance meter is set as above, a measuring signal is fed to
the conductive line 110 of the impedance meter so as to measure the
impedance of the path from the feed plate 3 of the plasma
processing apparatus to the chassis 21 via the plasma space 60.
[0257] In this manner, a uniform current flows to the measuring
object regardless of the size of the measuring object or the
distance between two points to be measured. Also, by setting a
residual impedance which does not affect the measurement of the
impedance of the measuring object, the impedance measurement can be
performed with precision.
[0258] In this embodiment, the substrate 16 is placed on the
susceptor electrode 8, and the first series resonant frequency
f.sub.0 and the power frequency f.sub.e are set in relation to the
plasma excitation electrode 4. However, it is possible to place the
substrate 16 on the plasma excitation electrode 4 serving as a
cathode.
[0259] Second Embodiment
[0260] A plasma processing apparatus of a second embodiment will
now be described with reference to FIG. 7.
[0261] FIG. 7 is a cross-sectional view showing the outline of the
structure of a plasma processing apparatus of a second
embodiment.
[0262] The plasma processing apparatus of the second embodiment is
of a dual-frequency excitation type. The second embodiment differs
from the first embodiment shown in FIGS. 1 to 4 in that the power
is supplied to a susceptor electrode 8 side and that there is a
measuring terminal 61. A difference also lies in the setting of the
first series resonant frequency f.sub.0. The corresponding
components are given the same reference numerals and symbols and
the description thereof is omitted to avoid duplication.
[0263] In the plasma processing apparatus of this embodiment, the
first series resonant frequency f.sub.0 is so set that 1.3 times
the first series resonant frequency f.sub.0 of the plasma chamber
(plasma processing room) CN is larger than the power frequency
f.sub.e fed from the radiofrequency generator 1 to the plasma
chamber CN.
[0264] As shown in FIG. 7, in the plasma processing apparatus of
this embodiment, a susceptor shield 12 is disposed under the
susceptor electrode 8, and the shaft 13 and the susceptor electrode
8 are electrically isolated from the susceptor shield 12 by a gap
between the susceptor shield 12 and the susceptor electrode 8, and
by insulators 12C provided around the shaft 13. The insulators 12C
also serve to maintain a high vacuum in the chamber space 60. The
susceptor electrode 8 and the susceptor shield 12 are allowed to
move upward and downward by a bellows 11, thereby allowing
adjustment of the distance between a plasma excitation electrode 4
and the susceptor electrode 8. The susceptor electrode 8 is
connected to a second radiofrequency generator 27 via a feed plate
28 connected to the lower end of the shaft 13 and a matching
circuit 25 housed inside a susceptor-electrode-side matching box
26.
[0265] The feed plate 28 is covered by a chassis 29 connected to
the lower end of a supporting tube 12B of the susceptor shield 12.
The chassis 29 is connected to the matching box 26 via a shielding
line of a feed line 27A that is a coaxial cable so that the chassis
29 and the matching box 26 are grounded. In this manner, the
susceptor shield 12, the chassis 29, and the matching box 26 have
the same DC potential.
[0266] Herein, the matching circuit 25 for matching the impedance
between the second radiofrequency generator 27 and the susceptor
electrode 8 comprises a tuning coil 30 and a tuning capacitor 31
connected in series between the second radiofrequency generator 27
and the feed plate 28, and a load capacitor 32 connected in
parallel to the tuning coil 30 and the tuning capacitor 31. One end
of the load capacitor 32 is connected to the matching box 26 so as
to make a circuit having substantially the same structure as that
of the matching circuit 2A. The matching box 26 is set to a ground
potential via the shielding line of the feed line 27A, thereby
grounding one end of the load capacitor 32. As alternative
configurations, a tuning coil may be connected to the tuning coil
30 in series so as to form a circuit serving as a tuning coil, or a
load capacitor may be connected to the load capacitor in parallel
so as to form a circuit serving as a load capacitor.
[0267] The feed plate 28 is identical to the feed plate 3. The feed
plate 28 is screwed to the terminal of the matching circuit 25 and
to the shaft 13.
[0268] An impedance measuring terminal (resonant frequency
measuring terminal) 61 of the plasma chamber CN is provided at the
output end position PR of the tuning capacitor 24, which is a
passive device at the final output stage among the passive devices
of the matching circuit 2A. Note that the output end position PR is
within the region of the plasma chamber CN of this embodiment in
which the measurements are taken. The impedance measuring terminal
61 extends from the output end position PR, which defines the
measured region, as in the first embodiment, by a conductor and
lies outside the chassis 21.
[0269] In the plasma processing apparatus of this embodiment, a
substrate 16 is placed on the susceptor electrode 8, radiofrequency
voltage is applied to the plasma excitation electrode 4 and the
susceptor electrode 8 from a first radiofrequency generator 1 and
the second radiofrequency generator 27, respectively, while a
reaction gas is fed into a chamber space 60 through a gas feeding
tube 17 and shower holes 7 to generate a plasma, and plasma
processing such as deposition or the like is performed on the
substrate 16. During the process, a radiofrequency voltage of
approximately 13.56 MHz or more, and more specifically, a
radiofrequency voltage of 13.56 MHz, 27.12 MHz, 40.68 MHz, or the
like, is supplied from the first radiofrequency generator 1. Either
the same radiofrequency voltage as in the first radiofrequency
generator 1 or a radiofrequency voltage of a different frequency,
e.g., 1.6 MHz, may be supplied from the second radiofrequency
generator 27.
[0270] The first series resonant frequency f.sub.0 of the plasma
processing apparatus according to this embodiment is defined by
measurement, as in the first embodiment. Specifically, the first
series resonant frequency f.sub.0 of this embodiment is defined by
measurement, as shown in FIGS. 8 and 9.
[0271] FIG. 8 is an illustration for explaining the impedance
characteristics of the plasma processing apparatus of this
embodiment. FIG. 9 is an equivalent circuit of FIG. 8.
[0272] The state of the plasma chamber as viewed from the impedance
measuring terminal 61 is the object of the measurement in this
embodiment. In other words, as shown in FIG. 9, the measured region
starts from the impedance measuring terminal 61 and ends at the
position at which the matching circuit 25 is separated. When
measuring the impedance characteristic (radiofrequency
characteristic), the matching circuit 2A connected to the feed
plate 3 in parallel at the output end position PR during plasma
emission is removed from the plasma chamber CN, and the matching
circuit 25 connected to the susceptor electrode 8 during the plasma
emission is removed from the plasma chamber CN.
[0273] The reason or depicting the radiofrequency generators 1 and
27 in the drawing is not to show that power is being supplied but
to show how the matching circuits 2A and 25 are grounded. The
impedance characteristics cannot be measured while the power is
being supplied.
[0274] As shown by a broken line in FIG. 8, a probe 105 of an
impedance meter AN is connected to the impedance measuring terminal
61 and to the earth position of the plasma chamber CN, a chassis
21, for example. At this stage, the measuring frequency oscillated
by the impedance meter AN is varied over the range of 1 to 100 MHz
so as to measure the vector quantity (Z, .theta.) of the impedance
of the above-described measured region of the plasma chamber
CN.
[0275] Next, as shown in FIG. 10, both impedance Z (.OMEGA.) and
phase .theta. (degree) are plotted on the ordinates of the graph
having the measuring frequency f (MHz) as the abscissa. In the
graph, the ordinate at the left side corresponds to impedance Z
(.OMEGA.) and the ordinate at the right side corresponds to phase
.theta. (degree). Referring to the impedance characteristic curve
(shown by a solid line) and the phase curve (shown by a broken
line) in FIG. 5, the first series resonant frequency f.sub.0 is
defined as the lowest frequency among the frequencies assigned to
the minima Z.sub.min of the impedance, i.e., the frequency assigned
to a phase .theta. of zero when the phase .theta. first goes from
positive to negative while the measuring frequency f is
increased.
[0276] In the thus determined first series resonant frequency
f.sub.0, the following electrical radiofrequency factors within the
above-described measured region are taken into account, as shown in
FIG. 8:
[0277] Inductance L.sub.f and resistance R.sub.f of the feed plate
3;
[0278] Plasma electrode capacitance C.sub.e between the plasma
excitation electrode 4 and the susceptor electrode 8;
[0279] Inductance L.sub.C and resistance R.sub.C of the supporting
tube 12B of the susceptor shield 12;
[0280] Inductance L.sub.B and resistance R.sub.B of the bellows
11;
[0281] Inductance L.sub.A and resistance R.sub.A of the chamber
wall 10;
[0282] Capacitance C.sub.A between the gas feeding tube 17 and the
plasma excitation electrode 4 via the insulator 17a;
[0283] Capacitance C.sub.B between the plasma excitation electrode
4 and the chassis 21; and
[0284] Capacitance C.sub.C between the plasma excitation electrode
4 and the chamber wall 10.
[0285] These electrical radiofrequency factors are arranged in the
same manner as in the circuit for generating plasma using
radiofrequency current so as to form an equivalent circuit shown in
FIG. 9. In this equivalent circuit, the inductance L.sub.f and
resistance R.sub.f of the feed plate 3, the plasma electrode
capacitance C.sub.e between the plasma excitation electrode 4 and
the susceptor electrode 8, the inductance L.sub.C and resistance
R.sub.C of the supporting tube 12B of the susceptor shield 12, the
inductance L.sub.B and resistance R.sub.B of the bellows 11, and
the inductance L.sub.A and resistance R.sub.A of the chamber wall
10 are connected in series in that order. The resistance R.sub.A is
grounded. The equivalent circuit further includes the capacitance
C.sub.A, the capacitance C.sub.B, and the capacitance C.sub.C,
connected in parallel between the resistance R.sub.f and the plasma
electrode capacitance C.sub.e and each grounded at one end thereof.
By determining the impedance characteristics of this equivalent
circuit, the first series resonant frequency f.sub.0 of this
embodiment can be defined.
[0286] It is arranged that the first series resonant frequency
f.sub.0 is set so that 1.3 times the first series resonant
frequency f.sub.0 is larger than the power frequency f.sub.e
supplied from the radio frequency generator 1.
[0287] Examples of methods for adjusting and setting the first
series resonant frequency f.sub.0 are as follows:
[0288] (1) Adjusting the shape and the length of the feed plate
3;
[0289] (2) Adjusting the overlapping area of the plasma excitation
electrode 4 and the chamber wall 10;
[0290] (3) Increasing the thickness of the insulating material
disposed between the plasma excitation electrode 4 and the chamber
wall 10; and
[0291] (4) Adjusting the susceptor electrode 8 and the chamber wall
10, such as connecting them with a conductor.
[0292] For example, in the plasma processing apparatus of this
embodiment, the power frequency f.sub.e is set to 40.68 MHz and the
impedance Z (.OMEGA.) and the phase .theta. (deg) relative to the
measuring frequency f (MHz) ranging from 1 to 100 MHz are measured
to give an impedance characteristic curve and a phase curve, as
shown in FIG. 10. The first series resonant frequency f.sub.0 is
then adjusted to 42.5 MHz so that relationship (3) below is
satisfied.
1.3f.sub.0>f.sub.e (3)
[0293] The plasma processing apparatus of this embodiment has the
same advantages as the first embodiment. Furthermore, in this
embodiment, the impedance measuring terminal 61 for the plasma
chamber CN is connected to the output end position PR of the
matching circuit 2A of the plasma chamber CN, thereby facilitating
attachment of a probe when the impedance characteristic of the
plasma chamber CN is measured. In this manner, the operation
efficiency during the measurement of the first series resonant
frequency f.sub.0 can be improved.
[0294] As shown in FIG. 7, the impedance measuring terminal 61 of
this embodiment penetrates through the matching box 2.
Alternatively, the radiofrequency generator 1 and the matching box
2 may be configured to be removable from the plasma processing
apparatus during the impedance measuring, without having the
impedance measuring terminal 61 penetrating the matching box 2.
[0295] Third Embodiment
[0296] A plasma processing apparatus according to a third
embodiment will now be described with reference to the
drawings.
[0297] FIG. 11 is a cross-sectional view illustrating the outline
structure of the plasma processing apparatus of a third
embodiment.
[0298] The plasma processing apparatus of this embodiment is of a
dual-frequency excitation type. The third embodiment differs from
the second embodiment in the structure around the impedance
measuring terminal 61, and the setting of the first series resonant
frequency f.sub.0 and a series resonance frequency f.sub.0'. The
same components in the embodiments are given the same reference
numerals and the explanation thereof is omitted.
[0299] In the plasma processing apparatus of the third embodiment,
the first series resonant frequency f.sub.0 of a plasma chamber
(plasma processing chamber) CN is set larger than three times the
power frequency f.sub.e supplied from a radiofrequency generator 1
to the plasma chamber CN. Meanwhile, the series resonant frequency
f.sub.0', defined by the capacitance C.sub.e between electrodes 4
and 8, is set larger than the product of the power frequency
f.sub.e and the square root of the distance d between the
electrodes/total distance .delta. of portions not emitting
plasma.
[0300] As shown in FIG. 11, the plasma processing apparatus of this
embodiment comprises switches for switching a matching circuit 2A
to/from an impedance measuring terminal (resonant frequency
measuring terminal) 61, the switches being disposed in the vicinity
of an output end position PR of the matching circuit 2A. More
specifically, a switch SW1 disposed between the matching circuit 2A
and the feed plate 3, and a switch SW2 disposed between an
impedance meter AN and the feed plate 3, are provided.
[0301] The switches SW1 and SW2 serve to electrically disconnect a
terminal of the feed plate 3 from the impedance measuring terminal
61 while securing the electrical connection between the terminal of
the feed plate 3 and the output end PR of the matching circuit 2A
during plasma excitation. In contrast, during measurement of the
resonant frequency of the plasma chamber CN, the switches SW1 and
SW2 serve to secure the electrical connection between the terminal
of the feed plate 3 and the impedance measuring terminal 61 while
electrically disconnecting the feed plate 3 from the output end PR
of the matching circuit 2A.
[0302] The impedance characteristics (resonant frequency
characteristics) when the switches SW1 and SW2 connect the feed
plate 3 and the matching circuit 2A, and the impedance
characteristics (resonant frequency characteristics) when the
switches SW1 and SW2 connect the impedance measuring terminal 61
and the feed plate 3, are set to be equal. In other words, the
impedance Z.sub.1, in the vicinity of the switch SW1 and the
impedance Z.sub.2 in the vicinity of the switch SW2 are set to be
equal, as will be described below with reference to FIG. 11.
[0303] To be more specific, the resonant frequency characteristics
measured at the position of the output end PR of the matching
circuit 2A when the switches 1 and 2 electrically disconnect the
terminal of the feed plate 3 from the impedance measuring terminal
61 while securing the electrical connection between the terminal of
the feed plate 3 and the output end PR of the matching circuit 2A,
and the resonant frequency characteristics measured at the
impedance measuring terminal (resonant frequency measuring
terminal) 61 when the switches SW1 and SW2 secure the electrical
connection between the terminal of the feed plate 3 and the
impedance measuring terminal 61 while electrically disconnecting
the feed plate 3 from the output end PR of the matching circuit 2A,
are set to equal each other.
[0304] In other words, referring to FIG. 11, the impedance Z.sub.1
at the output end position PR side of the matching circuit, 2A,
i.e., the impedance between the output end position PR and a branch
point B which branches to the switch SW2, when the switch SW1 is
closed to connect the matching circuit 2A while opening the switch
SW2, and the impedance Z.sub.2 at the impedance measuring terminal
61 side, i.e., the impedance between the impedance measuring
terminal 61 and the branch point B which branches to the switch
SW1, when the switch SW2 is closed to connect the impedance
measuring terminal 61 while opening the switch SW1, are set to
equal each other.
[0305] As in the second embodiment shown in FIG. 8, a detachable
probe of the impedance meter AN is connected to the impedance
measuring terminal 61. The detachable probe is connected to a
grounded part of the plasma chamber CN, for example, a chassis
21.
[0306] The first series resonant frequency f.sub.0 of the plasma
processing apparatus according to this embodiment is determined by
measuring impedance characteristics as in the second embodiment,
and more specifically, as shown in FIGS. 11 and 12.
[0307] FIG. 12 is a circuit configuration of an equivalent circuit
for measuring the impedance characteristics of the plasma
processing apparatus of this embodiment shown in FIG. 11.
[0308] Having the switch SW1 closed and the switch SW2 opened, a
substrate 16 is placed on a susceptor electrode 8, and
radiofrequency voltage is applied to a plasma excitation electrode
4 and a susceptor electrode 8 from a first radiofrequency generator
1 and a second radiofrequency generator 27, respectively, at the
same time while supplying a reaction gas to a chamber space 60
through a gas feeding tube 17 and shower holes 7 so as to generate
plasma. The substrate is plasma-treated, for example, and is
subjected to deposition using this plasma. At this time, a
frequency power of approximately 13.56 MHz or more, and more
precisely, 13.56 MHz, 27.12 MHz, 40.68 MHz, or the like, is fed to
the plasma excitation electrode 4 from the first radiofrequency
generator 1. The second radiofrequency generator 27 may supply
either power having the same frequency as the first radiofrequency
generator 1 or power of a different frequency, for example,
approximately 1.6 MHz.
[0309] As for the measured region of the plasma chamber CN of this
embodiment, the plasma chamber CN as viewed from the impedance
measuring terminal 61 is to be measured. Referring to FIG. 11,
since the impedance Z.sub.1, in the vicinity of the switch SW1 and
the impedance Z.sub.2 in the vicinity of the switch SW2 are set to
equal each other, the thus determined measured region is the same
as that viewed from the output end position PR.
[0310] In this manner, the matching circuit 2A can be separated
from the measured region simply using the switch SW1, as shown in
FIG. 11, in contrast to the first and second embodiments which
required the circuits to be mechanically detached in order to
electrically disconnect the matching circuit 2A and exclude the
same from the measured region during measurement of the impedance.
Thus, this embodiment simplifies measurement of the impedance
characteristics of the plasma chamber CN.
[0311] The measured region of the third embodiment includes the
switch SW2, which is not included in the second embodiment. Such an
arrangement is made because of the contribution of the switch SW1
to the impedance characteristics, i.e., because the switch SW1 is
closed during the plasma generation. When the vicinity of the
switch SW2 having impedance Z.sub.2, which is equal to impedance
Z.sub.1 in the vicinity of the switch SW1, is included in the
above-described measured region, the measured region of the plasma
chamber CN as viewed from the impedance measuring terminal 61 can
be made identical to the configuration of the circuit during the
actual plasma generation, thereby improving the accuracy of the
impedance measurement.
[0312] The vector quantity (Z, .theta.) of the impedance in
relation to the above-described measured region of the plasma
chamber CN is determined using a measuring frequency oscillated by
the impedance meter, the measuring frequency being varied over the
range of 1 MHz to 150 MHz, as in the second embodiment shown in
FIGS. 7 to 9, while opening the switch SW1 and closing the switch
SW2. It becomes possible to measure the impedance characteristics
and to define the first series resonant frequency f.sub.0 simply by
switching the switches SW1 and SW2 without having to remove the
matching circuit 2A from the plasma chamber CN or attach/detach the
impedance-measuring probe 105 of the second embodiment shown in
FIG. 8.
[0313] Next, as shown in FIG. 13, the impedance Z (.OMEGA.) and the
phase .theta. (deg) are plotted on the ordinates of a graph having
the abscissa assigned to the measuring frequency f (MHz). In the
graph, the ordinate at the left is assigned to the impedance Z
(.OMEGA.) and the ordinate at the right is assigned to the phase
.theta. (deg). The first series resonant frequency f.sub.0 is
defined as the lowest frequency among the frequencies assigned to
the minima Z.sub.min of the impedance in the impedance
characteristics curve and the phase curve, i.e., the frequency at a
phase .theta. of zero when the phase .theta. first goes from
negative to positive as the measuring frequency f is increased.
[0314] In the thus determined first series resonant frequency
f.sub.0, the following electrical radiofrequency factors within the
above-described measured region are taken into account, as shown in
FIG. 12:
[0315] Inductance L.sub.SW and resistance R.sub.SW of the switch
SW2;
[0316] Inductance L.sub.f and resistance R.sub.f of the feed plate
3;
[0317] Plasma electrode capacitance C.sub.e between the plasma
excitation electrode 4 and the susceptor electrode 8;
[0318] Capacitance C.sub.S between the susceptor electrode 8 and a
susceptor shield 12;
[0319] Inductance L.sub.C and resistance R.sub.C of a supporting
tube 12B of the susceptor shield 12;
[0320] Inductance L.sub.B and resistance R.sub.B of a bellows
11;
[0321] Inductance L.sub.A and resistance R.sub.A of a chamber wall
10;
[0322] Capacitance C.sub.A between a gas feeding tube 17 and the
plasma excitation electrode 4 via an insulator 17a;
[0323] Capacitance C.sub.B between the plasma excitation electrode
4 and the chassis 21; and
[0324] Capacitance C.sub.C between the plasma excitation electrode
4 and the chamber wall 10.
[0325] These electrical radiofrequency factors are arranged in the
same manner as in the circuit for generating plasma using
radiofrequency current so as to form an equivalent circuit shown in
FIG. 12. In this equivalent circuit, the inductance L.sub.SW and
resistance R.sub.SW of the switch SW2, the inductance L.sub.f and
resistance R.sub.f of the feed plate 3, the plasma electrode
capacitance C.sub.e between the plasma excitation electrode 4 and
the susceptor electrode 8, the capacitance C.sub.S between the
susceptor electrode 8 and a susceptor shield 12, the inductance
L.sub.C and resistance R.sub.C of a supporting tube 12B of the
susceptor shield 12, the inductance L.sub.B and resistance R.sub.B
of the bellows 11, and the inductance L.sub.A and resistance
R.sub.A of a chamber wall 10, are connected in series in that
order, while having the resistance R.sub.A grounded. The equivalent
circuit further comprises capacitance C.sub.A, capacitance C.sub.B,
and capacitance C.sub.C connected in parallel between the
resistance R.sub.f and the plasma electrode capacitance C.sub.e,
each having one end thereof grounded. By measuring the impedance
characteristics of this equivalent circuit, the first series
resonant frequency f.sub.0 of this embodiment can be defined.
[0326] The thus defined first series resonant frequency f.sub.0 is
set larger than three times the power frequency f.sub.e supplied
from the radiofrequency generator 1.
[0327] Examples of methods for setting the first series resonant
frequency f.sub.0 are as follows:
[0328] (1) Adjusting the length (shape) of the feed plate 3;
[0329] (2) Reducing the overlapping area of the plasma excitation
electrode 4 and the chamber wall 10;
[0330] (3) Increasing the thickness of the insulating material
provided between the plasma excitation electrode 4 and the chamber
wall 10; and
[0331] (4) Short-circuiting the susceptor shield 12 and the chamber
wall 10 using a conductor.
[0332] For example, in the plasma processing apparatus of this
embodiment, the power frequency f.sub.e is set to 40.68 MHz and the
impedance Z (.OMEGA.) and the phase .theta. (deg) relative to the
measurement frequency f (MHz) ranging from 0 to 150 MHz are
measured to give an impedance characteristic curve and a phase
curve, as shown in FIG. 6. The first series resonant frequency
f.sub.0 is then set to 123.78 MHz so that relationship (4) below is
satisfied.
f.sub.0>3f.sub.e (4)
[0333] In this embodiment, a series resonant frequency f.sub.0',
defined by the plasma electrode capacitance C.sub.e between the
plasma excitation electrode 4 and the susceptor electrode 8, is set
larger than three times the power frequency f.sub.e described above
so that relationship (5) below is satisfied.
f.sub.0'>3f.sub.e (5)
[0334] The series resonant frequency f.sub.0' is defined from the
impedance characteristic between the plasma excitation electrode 4
and the susceptor electrode 8. The impedance characteristic thereof
is measured as in determining the first series resonant frequency
f.sub.0 described above.
[0335] To be more specific, the impedance characteristic is
measured at one end of the susceptor electrode 8 having the other
end grounded, and the least significant frequency among the
frequencies assigned to the minima Z is defined as the series
resonant frequency f.sub.0'.
[0336] The series resonant frequency f.sub.0' is radiofrequency
electrical characteristic dependent on the mechanical shape of the
plasma excitation electrode 4 and the susceptor electrode 8, and is
in proportion to the reciprocal of the square root of the plasma
electrode capacitance C.sub.e between the plasma excitation
electrode 4 and the susceptor electrode 8.
[0337] By using the series resonant frequency f.sub.0', the
frequency characteristic of the plasma excitation electrode 4 and
the susceptor electrode 8, which directly generate a plasma, can be
controlled. Consequently, power can be efficiently fed to the
plasma emission space, thereby improving the power consumption
efficiency and the process efficiency.
[0338] Furthermore, in this embodiment, the series resonant
frequency f.sub.0' defined by plasma electrode capacitance C.sub.e
between the plasma excitation electrode 4 and the susceptor
electrode 8 is set so that relationship (1) below is satisfied
relative to the power frequency f.sub.e. 2 f 0 ' > d f e ( 1
)
[0339] Wherein d represents the distance between the plasma
excitation electrode (plasma excitation electrode) 4 and the
susceptor electrode (counter electrode) 8, and .delta. represents
the total of the distance between the plasma excitation electrode 4
and the generated plasma and the distance between the susceptor
electrode 8 and the generated plasma, as will be described in
detail below.
[0340] FIG. 14 is a diagram showing a state of the space between
two electrodes when a plasma is being generated.
[0341] As shown in FIG. 14, the plasma excitation electrode 4 and
the susceptor electrode 8 are each of a parallel plate type, and
the distance therebetween is represented by d. The total of the
distance between the plasma excitation electrode 4 and the
generated plasma, and the distance between the susceptor electrode
8 and the generated plasma, is represented by .delta.. In other
words, distance .delta..sub.a of the plasma non-emitting portion
between the plasma excitation electrode 4 and a plasma emitting
region P, which can be visually recognized during plasma emission,
and distance .delta..sub.b of the plasma non-emitting portion
between the plasma emitting region P and the susceptor electrode 8
satisfy relationship (6) below.
.delta..sub.a+.delta..sub.b=.delta. (6)
[0342] Herein, a model capacitance C.sub.0" between the electrodes
4 and 8 during plasma emission can be obtained from the distance d
between the electrodes 4 and 8 and the total .delta. of the
distances of the portions not emitting plasma between the
electrodes 4 and 8.
[0343] The plasma emitting region P between the parallel plate
electrodes 4 and 8 can be regarded as a conductor during plasma
emission. Thus, the distance between the electrodes 4 and 8 can be
regarded as .delta.. Consequently, since capacitance C.sub.0"
between the parallel plate electrodes 4 and 8 during plasma
emission is inversely proportional to the distance between the
electrodes 4 and 8, the apparent capacitance C.sub.0" during plasma
emission is d/.delta. times the capacitance C.sub.0, wherein
C.sub.0 is the capacitance when the plasma is not emitted.
C.sub.0.varies.1/d
C.sub.0".varies.1/.delta.
.thrfore.C.sub.0".varies.d/.delta..multidot.C.sub.0 (7)
[0344] Since the series resonant frequency f.sub.0' is proportional
to the reciprocal of the square root of the capacitance C.sub.0,
the series resonant frequency f.sub.0" between the electrodes 4 and
8 during plasma emission is proportional to the reciprocal of the
square root of the capacitance C.sub.0", i.e., proportional to the
reciprocal of the square root of d/.delta.. 3 f 0 ' 1 / C 0 f 0 " 1
/ C 0 " f 0 " ( d / ) - 1 / 2 f 0 ' ( 8 )
[0345] The relationship between the series resonant frequency
f.sub.0" between the electrodes 4 and 8 during plasma emission and
the power frequency f.sub.e is set the same as the relationship
between first series resonant frequency f.sub.0 and power frequency
f.sub.e.
f.sub.0">f.sub.e (9)
[0346] Using relationship (8), relationship (9) can be rewritten as
relationship (1) described above.
[0347] When the series resonant frequency f.sub.0" and the power
frequency f.sub.e satisfy relationship (1), the relationship
between the value of series resonant frequency f.sub.0" defined
from the model capacitance C.sub.0" during plasma emission and the
value of the series resonant frequency f.sub.0' defined from the
capacitance between the electrodes 4 and 8 when no plasma is
emitted can be optimized. By setting the value of the product of
series resonant frequency f.sub.0' and the reciprocal of the square
root of d/.delta. to be larger than the power frequency f.sub.e, it
becomes possible to adjust the series resonant frequency f.sub.0"
between the electrodes 4 and 8 during plasma emission relative to
power frequency f.sub.e, thereby improving the power consumption
efficiency during plasma emission.
[0348] The plasma processing apparatus of this embodiment has the
following advantages in addition to the advantages the first
embodiment. Because the switches SW1 and SW2 are provided while an
impedance meter is detachably attached to the impedance measuring
terminal 61, and the impedances Z.sub.1 and Z.sub.2 thereof are set
equal to each other, the measurement of the impedance
characteristic and determining the first series resonant frequency
f.sub.0 can be readily performed by simply switching the switches
SW1 and SW2 without having to separate the matching circuit 2A from
the plasma chamber CN. Moreover, because the impedance determined
at the impedance meter AN connected to the impedance measuring
terminal 61 can be considered equal to the impedance measured at
the output position PR of the final output stage of the matching
circuit 2A, neither correction nor reduction is necessary to yield
the first series resonant frequency f.sub.0. Thus, the efficiency
of operation can be improved, and the measurement of the first
series resonant frequency f.sub.0 can be accurately carried
out.
[0349] Moreover, by setting the series resonant frequency f.sub.0'
and the power frequency f.sub.e, the frequency characteristic of
the above-described electrodes 4 and 8 for plasma emission can be
controlled, voltage can be effectively applied to the plasma
emission space, and the power consumption efficiency and the
process efficiency can be further improved.
[0350] In this embodiment, two switches, namely, the switches SW1
and SW2, are provided. Alternatively, a single switch may be used
to switch the connections as long as the impedance between the
branching point to the output end position PR and the impedance
between the branching point to the probe are set to equal each
other.
[0351] Furthermore, in each of the above-described first to third
embodiments, the power frequency f.sub.e and the first series
resonant frequency f.sub.0 are set in relation to the plasma
excitation electrode 4. Alternatively, they may be set in relation
to the susceptor electrode 8. In such a case, an output end
position PR' of the matching circuit 25 may be set to define the
region in which the impedance is measured, as shown in FIGS. 7 and
11. When the impedance characteristic of the plasma chamber CN is
measured from the susceptor electrode 8 side, the matching circuit
25 is removed from the plasma chamber CN at the output end position
PR', which serves as a measuring point.
[0352] Moreover, in addition to the plasma processing apparatus
using the parallel plate type electrodes 4 and 8, the present
invention can be applied to an inductive coupled plasma (ICP)
excitation type plasma processing apparatus, a radial line slot
antenna (RLSA) type plasma processing apparatus, or a reactive ion
etching (RIE) process apparatus.
[0353] Furthermore, the structure in which the feed panel 3 and the
plasma excitation electrode 4 are combined or the structure in
which the matching circuit 2A is directly connected to the
electrode may also be employed. In such a case, the above-described
measured region starts from the output end PR of the matching
circuit 2A
[0354] Also, target materials may be provided instead of the
electrodes 4 and 8 so as to perform a plasma process such as
sputtering.
[0355] Next, an embodiment of a performance validation system of
the plasma processing apparatus according to the present invention
will be described with reference to the drawings. Hereinafter, the
person who distributes and maintains the plasma processing
apparatus is referred to as a "maintenance engineer".
[0356] FIG. 20 is a diagram illustrating the configuration of a
performance validation system of the plasma processing apparatus
according to the present invention.
[0357] Referring to FIG. 20, the performance validation system
comprises a customer's terminal (client terminal) C1, an engineer's
terminal (client terminal) C2, a server computer (hereinafter
simply referred to as "server") S which functions as operational
performance information providing means, a database computer
(hereinafter simply referred to as "database") D which stores
information, and a public line N. The customer's terminal C1 and
the engineer's terminal C2, the server S, and the database D are
linked to one another via the public line N.
[0358] The terminals C1 and C2 have a function to communicate with
the server S using a commonly-used internet communication protocol,
such as TCP/IP or the like. The customer's terminal C1 serves as a
customer-side information terminal for validating, via the public
line N, the state of the performance of the plasma chamber CN that
the customer purchased from the maintenance engineer. The
customer's terminal C1 also has a function to access an information
web page such as a "plasma chamber CN performance information page"
stored in the server S. The engineer's terminal C2 allows the
maintenance engineer to upload "first series resonant frequency
f.sub.0 information", which partially constitutes the "performance
information", and to receive e-mails sent from the customer through
the customer's terminal
[0359] Communication with the server S is achieved through a modem
when the public line N is an analog line or through a dedicated
terminal adapter or the like when the public line N is a digital
line such as an integrated services digital network (ISDN).
[0360] The server S is a computer that provides performance
information. The server S transmits the performance information to
the customer's terminal C1 using an internet communication protocol
upon request from the customer's terminal C1 requesting the display
of the information. Herein, each of the customers who purchased the
plasma chambers receives an "access password" for accessing the
performance information when the plasma processing apparatus is
delivered to the customer from the maintenance engineer. The
password is required when the customer wishes to access operation
and maintenance information, which is part of the performance
information, and the server S sends the operation and maintenance
information to the customer's terminal C1 only when a registered
access password is provided.
[0361] The above-described "performance information", details of
which will be described in a later section, comprises information
regarding models of the plasma processing apparatus available from
the maintenance engineer, information regarding quality/performance
of each model in the form of specifications, information regarding
parameters indicative of quality/performance of specific
apparatuses delivered to customers, and information regarding
parameters and maintenance history.
[0362] The latter two types of information among the information
described above, i.e., the information regarding
quality/performance of specific apparatuses and the information
regarding parameters and maintenance history, are accessible only
from the customers provided with access passwords.
[0363] The performance information described above is provided in
the form of "operation and maintenance information" and "standard
performance information". The operation and maintenance information
is a type of information provided from the maintenance engineer or
the customer to the server S to indicate the actual state of
operation and maintenance. The standard performance information is
a type of information stored in the database D and serves as a
catalog accessible by potential customers. The "standard
performance information" is an objective description regarding the
performance of the plasma processing carried out in the plasma
chamber CN and allows prediction of the deposition state when
deposition processes such as plasma-enhanced CVD and sputtering
processes are concerned.
[0364] In this embodiment, all the information included in the
standard performance information is stored in the database D.
[0365] Upon the request from the customer's terminal C1 requesting
display of "performance information", the server S retrieves the
necessary "standard performance information" from the database D
and sends the information to the customer's terminal C1 of the
customer in the form of a performance information page. When a
customer sends a request to access the "performance information"
along with the access password of the customer, the server S
retrieves the necessary standard performance information from the
database D as described above, constructs the performance
information by combining the thus retrieved information and the
operation and maintenance information provided from the maintenance
engineer through the engineer's terminal C2, and sends the
performance information page containing this information to the
customer's terminal C1 of the customer.
[0366] The database D stores the "standard performance
information", which is part of the "performance information",
according to the models of the plasma chambers CN, reads out the
"standard performance information" in response to a search request
sent from the server S, and transfers the retrieved information to
the server S. Although only one server S is illustrated in FIG. 20,
a plurality of servers are provided in this embodiment. In this
respect, it is useful to store general purpose "standard
performance information" in the database D instead of these servers
in order for the information to be shared among the plurality of
servers managed by maintenance engineers from a plurality of
locations.
[0367] Next, an operation of the thus-configured performance
validation system of the plasma chamber CN will be explained in
detail with reference to the flowchart shown in FIG. 21. The
flowchart illustrates the process of providing the "performance
information" at the server S.
[0368] Generally, the maintenance engineer presents, as a reference
for purchase, the "standard performance information" (among the
"performance information") of the model of plasma chamber CN which
the maintenance engineer is attempting to sell to the customer. The
customer is able to understand the performance of the plasma
chamber CN, and possible plasma processes using the plasma chamber
CN, through this "standard performance information".
[0369] Also, the maintenance engineer presents, to the customer who
purchased and received the plasma chamber CN, the "operation and
maintenance information" of the purchased apparatus (among the
"performance information") as operating parameters as well as the
"standard performance information," which serves as the reference
during the operation. The customer, i.e., the user of the plasma
chamber CN, may validate the operation of his/her plasma chamber CN
by comparing the "standard performance information" and the
"operation and maintenance information" so as to determine whether
it is necessary to perform maintenance and to be informed of the
state of the plasma processing.
[0370] For example, the customer who is considering purchasing a
new plasma chamber CN from the maintenance engineer may access the
server S to easily check the "standard performance information" of
the plasma chamber CN the customer is intending to purchase in the
following manner.
[0371] When the customer accesses the server S, a request for
access is first sent from the customer's terminal C1 to the server
S based on an IP address of the server S set in advance.
[0372] Upon receiving the request for access (Step S1), the server
S transfers a catalog page CP to the customer's terminal C1 (Step
S2).
[0373] FIG. 22 shows an example of the catalog page (main page) CP
sent from the server S to the customer's terminal C1 through the
steps described above. The catalog page CP comprises model
selection buttons K1 to K4 for displaying the "standard performance
information" (among the "performance information") according to
models available from the maintenance engineer, and a user button
K5 for requesting the display of a customer page exclusive to the
customer to whom the maintenance engineer delivered the plasma
chamber CN.
[0374] For example, a customer may select one of the model
selection buttons K1 to K4 by a pointing device (for example, a
mouse) of the customer's terminal C1 so as to specify which model
of the plasma chamber CN the customer desires to obtain the
information about. Such a selection is regarded as the request for
accessing the "standard performance information" (among the
"performance information"), and a request to that effect is sent to
the server S.
[0375] Upon receipt of the request (Step S3), the server S sends
the customer's terminal C1 a subpage containing the requested
information regarding the selected model. That is, when display of
"standard performance information" is requested specifying a model
(A), the server S retrieves data such as "vacuum performance", "gas
supply/discharge property", "temperature performance", "electrical
performance of the plasma processing chamber", and the like from
the database D and sends the customer's terminal C1 a
specifications page CP1 (shown in FIG. 23) containing this
data.
[0376] As shown in FIG. 23, the specifications page CP1 comprises
an apparatus model section K6 indicating the selected model of the
apparatus, a vacuum performance section K7, a gas supply/discharge
performance section K8, a temperature performance section K9, and
an electrical performance section K10 indicating the electrical
performance of the plasma processing chamber. These constitute the
"standard performance information" of the selected model, and each
contains the following descriptions.
[0377] The vacuum performance section K7 contains
[0378] ultimate degree of vacuum: 1.times.10.sup.-4 Pa or less;
and
[0379] operational pressure: 30 to 300 Pa.
[0380] The a gas supply/discharge performance section K8 contains
p1 maximum gas flow rates:
1 SiH.sub.4 100 SCCM, NH.sub.3 500 SCCM, N.sub.2 2,000 SCCM; and
discharge property: 20 Pa or less in a flow of 500 SCCM.
[0381] discharge property: 20 Pa or less in a flow of 500 SCCM.
[0382] The temperature performance section K9 contains
[0383] heater temperature: 200 to 350.+-.10.degree. C.; and
[0384] chamber temperature: 60 to 80.+-.2.0.degree. C.
[0385] Herein, the SCCM (standard cubic centimeters per minute)
values represent the corrected gas flow rate at standard conditions
(0.degree. C. and 1,013 hPa) and the unit thereof is
cm.sub.3/min.
[0386] In the electrical performance section K10, a value of the
first series resonant frequency f.sub.0 described in the first to
third embodiment above and the relationship between the setting
range of the first series resonant frequency f.sub.0 and the power
frequency f.sub.e are described. In addition to these, values such
as resistance R.sub.e and reactance X.sub.e of the plasma chamber
CN at the power frequency f.sub.e, plasma capacitance C.sub.0
between the plasma excitation electrode 4 and the susceptor
electrode 8, loss capacitance C.sub.X between the plasma excitation
electrode 4 and each of the components which serve as ground
potential of the plasma chamber, and the like are included in the
description. Furthermore, in the specification page CP1, a
performance guarantee statement such as "we guarantee that each of
the parameters is within the range of settings described in this
page at the time of delivery of the plasma chamber" is
included.
[0387] In this manner, the overall radiofrequency electrical
characteristics of the plasma chamber CN can be presented to a
potential purchaser as a novel reference which has never been
considered before. The performance information can be printed out
at the customer's terminal C1 or the engineer's terminal C2 to make
a hard copy thereof so that the information can be presented in the
form of a catalog or specifications describing the performance
information containing the above-described detailed information.
When settings of the first series resonant frequency f.sub.0,
resistance R.sub.e, reactance X.sub.e, capacitances C.sub.0,
C.sub.X, and the like, and the performance guarantee statement are
presented to a potential purchaser through a terminal such as
customer's terminal C1, through a catalog, or through a
specification, the potential purchaser may judge the performance of
the plasma chamber just as if he/she is examining electrical
components and may then purchase the plasma chamber CN from the
maintenance engineer based on that judgement.
[0388] After the server S completes the transmission of the
above-described subpage to the customer's terminal C1, the server S
waits for the request for the display of another subpage if a
log-off request from the customer's terminal C1 is not received
(Step S5). If a log-off request from the customer's terminal C1 is
received by the server S, the server S terminates the interaction
with the customer's terminal C1.
[0389] The customer who purchased and obtained the plasma chamber
CN from the maintenance engineer can easily check the "performance
information" of the specific plasma chamber that the customer
purchased by accessing the server as below.
[0390] When the customer and the maintenance engineer exchange a
sales contract, a customer ID, which is assigned to the individual
customer and corresponds to a model number of the purchased plasma
chamber CN, and a "customer password" (access password) for
accessing the "operation and maintenance information" of that
plasma chamber CN are given to the individual customer by the
maintenance engineer. The server S sends the "operation and
maintenance information" to the customer's terminal C1 only when
the registered access password is provided.
[0391] A customer who wishes to access the information selects the
user button K5 in the above-described catalog page CP and sends the
request for the display of a customer page to the server S.
[0392] Upon receiving the request for the display (Step S3-B), the
server S sends a subpage prompting the customer to input his/her
"access password" (Step S6). FIG. 24 is an illustration of a
customer page CP2. The customer page CP2 comprises a customer ID
input field K11 and a password input field K12.
[0393] The customer page CP2 prompting the customer to input is
displayed at the customer's terminal C1. In response to the prompt,
the customer enters the "access password" and the "customer ID",
which are provided from the maintenance engineer, through the
customer's terminal C1 so as to allow the server S to identify the
specific plasma chamber CN.
[0394] At this stage, the customer enters the customer ID into the
customer ID input field K11 and the access password into the
password input field K12. The server S sends the "operation and
maintenance information" subpage previously associated to that
"access password" to the customer's terminal C1 (Step S9), only
when the server S receives the registered "customer ID" and the
"access password" from the customer's terminal C1 (Step S7).
[0395] In other words, the "operation and maintenance information"
is accessible only by the specific customer who exchanged the sales
contract for the above-described plasma chamber CN, i.e., who is in
possession of the registered "access password". A third party using
the server S cannot access the "operation and maintenance
information". Although the maintenance engineer often exchanges
sales contracts with a plurality of customers simultaneously and
delivers a plurality of plasma chambers CN for these customers
simultaneously, each of the customers is provided with an "access
password" unique to the customer and the plasma chamber CN, and is
capable of individually accessing the "operation and maintenance
information" associated to the "access password" assigned to that
customer.
[0396] Thus, it becomes possible to securely prevent confidential
information regarding the purchase of the plasma chamber from being
made available to other customers. Furthermore, each of the plasma
chambers can be individually identified even when a plurality of
plasma chambers CN are delivered at the same time. If the server S
does not receive a registered "access password" (Step S7), a
message refusing the access and prompting the customer to re-enter
the "access password" is sent to the customer's terminal C1 (Step
S8). If the customer erroneously entered the "access password", the
customer may take this opportunity to re-enter a legitimate
password to access the "operation and maintenance information".
[0397] When the ID and the password are verified (Step S7), the
server S retrieves data corresponding to the information requested
from the database D and sends it to the customer's terminal C1 in
the form of a subpage. That is, when the server S receives a
request from the customer's terminal C1 requesting display of the
"standard performance information" and the "operation and
maintenance information" of the specific plasma chamber CN
identified by the customer ID, data such as "vacuum performance",
"gas supply/discharge performance", "electric performance of the
plasma processing chamber", and the like are retrieved from the
database D by specifying the apparatus model, and a specification
page (subpage) CP3 containing this data is sent to the customer's
terminal C1 (Step S9).
[0398] FIG. 25 is an illustration of a maintenance history page
(subpage) CP 3 containing "operation and maintenance information",
which is sent from the server S to the customer's terminal C1. As
shown in FIG. 25, the maintenance history page CP3 comprises a lot
number section K13 indicating the serial number of the apparatus
purchased, the vacuum performance section K7, the gas
supply/discharge performance section K8, the temperature
performance section K9, the electrical performance section K10, a
vacuum performance maintenance section K14, a gas supply/discharge
performance maintenance section K15, a temperature performance
maintenance section K16, and an electrical property maintenance
section K17. These constitute the "standard performance
information" and the "operation and maintenance information" of the
specific plasma chamber that is purchased.
[0399] An example of the description contained in the vacuum
performance maintenance section K14 is as follows:
[0400] ultimate degree of vacuum: 1.3 .times.10.sup.-5 Pa or
less;
[0401] operational pressure: 200 Pa.
[0402] An example of the description contained in the gas
supply/discharge performance maintenance section K15 is as
follows:
[0403] gas flow rates:
2 SiH.sub.4 40 SCCM, NH.sub.3 160 SCCM, N.sub.2 600 SCCM; and
discharge property: 6.8 .times. 10.sup.-7 Pa .multidot.
m.sup.3/sec.
[0404] An example of the description contained in the temperature
performance maintenance section K16 is as follows:
[0405] heater temperature: 302.3.+-.4.9.degree. C.; and
[0406] chamber temperature: 80.1.+-.2.1.degree. C.
[0407] In the electrical performance maintenance section K17, the
measured value of the first series resonant frequency f.sub.0 and
the relationship with the power frequency f.sub.e are described.
The electrical property maintenance section K17 further includes
readings of the resistance R.sub.e and reactance X.sub.e of the
plasma chamber CN at a power frequency f.sub.e, the plasma
capacitance C.sub.0 between the plasma excitation electrode 4 and
the susceptor electrode 8, the loss capacitance C.sub.X between the
plasma excitation electrode 4, and each of the portions which serve
as the ground potential of the plasma chamber.
[0408] Each of the sections K14 to K17 of the maintenance history
keeps the actual readings of these parameters and the date they are
measured. The maintenance engineer or the customer regularly and
sequentially uploads, to the server S, the "operation and
maintenance information" of the individual plasma chambers
according to the amount of time elapsed since the delivery of the
chamber. Upon receiving the "operation and maintenance
information", the server S sequentially registers the data. The day
the information is uploaded to the server S is defined as the
"registration date".
[0409] The server S also retrieves the "performance information"
including such data as "vacuum performance", "gas supply/discharge
performance", "temperature performance", "electrical performance of
the plasma processing chamber", and the like from the database D,
and combines the retrieved information with the "operation and
maintenance information" so as to make the maintenance history page
CP3. In this manner, the customer can browse the "operation and
maintenance information" and the "standard performance information"
at the same time and compare the "operation standard information"
which serves as the reference during use and the "operation and
maintenance information" which serves as parameters indicating the
actual operational state. In this manner the customer better
understands the present state of the plasma process, can readily
validate the operation of the plasma chamber CN, and can determine
whether maintenance is necessary.
[0410] If a log-off request from the customer's terminal C1 is not
received by the server S after the completion of the transmission
of the above-described subpage CP3 to the customer's terminal C1,
the server S sends the customer's terminal C1 a message refusing
the connection (Step S8) and prompting the customer to re-enter the
"access password" or waits for the next request for display of
another subpage (Step S3). If the server S receives a log-off
request from the customer's terminal C1, then the server terminates
the interaction with the customer's terminal C1.
[0411] The performance validation system of the plasma chamber CN
according to this embodiment comprises: a customer-side information
terminal requesting, via a public line, access to performance
information indicating an operational performance state of the
previously described plasma chamber CN of the present invention
which the customer purchased from a maintenance engineer; an
engineer-side information terminal which allows the engineer to
upload the performance information; and performance information
providing means for providing the performance information uploaded
at the engineer-side information terminal to the customer-side
information terminal in response to a request from the
customer-side information terminal. Because the performance
information includes information regarding first series resonant
frequency f.sub.0, the standard performance information, and the
operation and maintenance information of the plasma chamber CN, and
is presentable to customers as a catalog or specification when
outputted through public lines and information terminals, it
becomes possible to provide the customer with information necessary
for making decisions to purchase the plasma chamber CN or to
readily present the customer who purchased the plasma chamber CN
with the information regarding operational performances and
maintenance information of the purchased plasma chamber.
[0412] Moreover, because the performance information includes the
first series resonant frequency f.sub.0 as a performance parameter,
the customer can estimate the performance of the plasma chamber CN,
thus allowing him/her to make proper decisions at the time of
purchase. Furthermore, the performance information can be output as
a catalog or a specifications.
EXAMPLES
[0413] In the following examples, the first series resonant
frequency f.sub.0 was varied so as to examine changes in layer
characteristics during the deposition process.
[0414] The plasma processing apparatus used was of a dual-frequency
excitation type. The plasma processing apparatus had radiofrequency
electrical characteristics identical to those of the equivalent
circuit shown in FIG. 15. The inductance L.sub.X was a combination
of the inductance L.sub.C of the shaft 13, the inductance L.sub.B
of the bellows 11, and the inductance L.sub.A of the chamber wall
10 shown in FIG. 12. The resistance R.sub.S was a combination of
the resistance R.sub.C of the shaft 13, the resistance R.sub.B of
the bellows 11, and the resistance R.sub.A of the chamber wall 10
shown in FIG. 12. The capacitance C.sub.X was a combination of the
capacitance C.sub.A between the gas feeding tube 17 and the plasma
excitation electrode 4 via the insulator 17a, the capacitance
C.sub.B between the plasma excitation electrode 4 and the chassis
21, and the capacitance C.sub.C between the plasma excitation
electrode 4 and the chamber wall 10 shown in FIG. 12.
Comparative Example 1
[0415] In Comparative Example 1, the power frequency f.sub.e was
set to 40.68 MHz and the first series resonant frequency f.sub.0
was set to 11.63 MHz. Each of the factors constituting the
equivalent circuit shown in FIG. 12, namely, the inductance L.sub.f
and the resistance R.sub.f of the feed plate 3, the plasma
electrode capacitance C.sub.e between the plasma excitation
electrode 4 and the susceptor electrode 8, the capacitance C.sub.S
between the susceptor electrode 8 and the susceptor shield 12
(earth), the inductance L.sub.S and the resistance R.sub.S of the
shaft 13, the bellows 11, and the chamber wall 10, and the
capacitance C.sub.X between the plasma excitation electrode 4 and
the earth, were actually measured. The results are shown in Table
1.
Example 1
[0416] The length of the feed plate 3 of the plasma processing
apparatus of Comparative Example 1 was changed so as to set the
first series resonant frequency f.sub.0 to 13.82 MHz, satisfying
the relationship 3f.sub.0>f.sub.e.
Example 2
[0417] The feed plate 3 was further changed from Example 1, and the
overlapping area of the susceptor electrode 8 and the chamber wall
10 was changed so as to set the first series resonant frequency
f.sub.0 to 30.01 MHz, satisfying the relationship
3f.sub.0>f.sub.e.
Example 3
[0418] The thickness of the insulator between the susceptor
electrode 8 and the chamber wall 10 was increased as compared to
Example 2 so as to set the first series resonant frequency f.sub.0
to 33.57 MHz, satisfying the relationship 1.3f.sub.0
>f.sub.e.
Example 4
[0419] The feed plate 3 was removed from the plasma processing
apparatus of Example 3, the tuning capacitor 24 of the matching
circuit 2A was directly connected to the susceptor electrode 8, and
the shield supporting plate 12A of the susceptor shield 12 and the
chamber wall 10 were short-circuited so as to set the first series
resonant frequency f.sub.0 to 123.78 MHz, satisfying the
relationship f.sub.0>3f.sub.e.
[0420] It is to be noted that in all Examples, the power frequency
f.sub.e was set to 40.68 MHz. The results are shown in Table 1.
3 TABLE 1 Comparative Example Example 1 Example 2 Example 3 Example
4 First series resonant 11.63 13.82 30.01 33.57 123.78 frequency
f.sub.0 (MHz) Inductance L.sub.f (nH) of the 184 130 92 92 2 feed
plate 3 Resistance R.sub.f (.OMEGA.) of the 4 3 3 3 1 feed plate 3
Capacitance C.sub.e (pF) 37 37 37 37 37 between electrodes
Capacitance C.sub.s (pF) 2250 2250 2250 2250 2250 between the
susceptor electrode 8 and earth Inductance L.sub.s (nH) of the 268
268 268 268 268 chamber wall, etc. Resistance R.sub.s (.OMEGA.) of
the 2 2 2 2 1 chamber wall, etc. Capacitance C.sub.s (pF) 980 980
250 180 180 between the plasma excitation electrode 4 and earth
[0421] In order to evaluate the results of Examples 1-4 and the
Comparative Example, a SiN.sub.X layer was deposited at 800 W and
400 W. The SiN.sub.X layers were evaluated as follows.
[0422] (1) Deposition rate and planar uniformity
[0423] The process for evaluating deposition rate and planar
uniformity included the following:
[0424] Step 1: Depositing a SiN.sub.X layer on a glass substrate by
plasma-enhanced CVD method;
[0425] Step 2: Patterning a resist layer by photolithography;
[0426] Step 3: Dry-etching the SiN.sub.X layer using SF.sub.6 and
O.sub.2;
[0427] Step 4: Separating the resist layer by ashing using
O.sub.2;
[0428] Step 5: Measuring step differences in the layer thickness
using a displacement meter;
[0429] Step 6: Calculating deposition rate from the deposition time
and the layer thickness; and
[0430] Step 7: Measuring the planar uniformity at 16 points on a
6-inch substrate surface.
[0431] (2) BHF etching rate
[0432] The process for evaluating the etching rates included the
following:
[0433] Steps 1 and 2: Same as the above Step 3: Immersing the
substrate in a BHF solution (HF:NH.sub.4F=1:10) for one minute;
[0434] Step 4: Rinsing the substrate with deionized water, drying
the substrate, and separating the resist layer using a mixture of
sulfuric acid and hydrogen peroxide
(H.sub.2SO.sub.4+H.sub.2O.sub.2);
[0435] Step 5: Measuring the step differences as in Step 5 above;
and
[0436] Step 6: Calculating the etching rate from the immersion time
and the step differences.
[0437] (3) Isolation voltage
[0438] The process for evaluating the isolation voltage included
the following:
[0439] Step 1: Depositing a chromium layer on a glass substrate by
sputtering and patterning the chromium layer to make a lower
electrode;
[0440] Step 2: Depositing a SiN.sub.X layer by a plasma-enhanced
CVD method;
[0441] Step 3: Forming an upper electrode by the same process as in
Step 1;
[0442] Step 4: Forming a contact hole for the lower electrode;
[0443] Step 5: Probing the upper and the lower electrodes to
measure the current-voltage characteristic (I-V characteristic) by
applying a voltage of approximately 200 V or less; and
[0444] Step 6: Defining the isolation voltage as the voltage V at
100 pA corresponding 1 .mu.A/cm.sup.2 in a 100 .mu.m square
electrode.
[0445] These results are shown in Table 2.
4 TABLE 2 Comparative Example 1 Example 1 Example 2 Example 3
Example 4 Power output 800 800 800 800 400 Deposition rate (nm/min)
30-100 100-450 100-450 100-550 100-550 max-min Planar uniformity
(%) >.+-.10 .about..+-.10 .about..+-.10 .+-.5 .+-.5 BHF etching
rate >200 .about.200 .about.200 .about.50 .about.50 (nm/min)
Isolation voltage .about.4 .about.7 .about.7 .about.9 .about.9
[0446] As is apparent from these results, when the relationship
3f.sub.0>f.sub.e was satisfied, the deposition rate and the
isolation voltage were improved. When the relationship
1.3f.sub.0>f.sub.e was satisfied, not only the deposition rate
and the isolation voltage, but also the planar uniformity and the
BHF etching rate were improved. When the relationship
f.sub.0>3f.sub.3 was satisfied, the same layer characteristics
were achieved at a power output of 400 W.
[0447] It can be concluded from the above that the performance of
the plasma processing apparatus was improved by setting the first
series resonant frequency f.sub.0 .
[0448] Fourth Embodiment
[0449] In accordance with a fourth embodiment of the present
invention, a plasma processing apparatus, and a performance
validation system and an inspection method thereof will now be
described with reference to the drawings.
[0450] FIG. 26 illustrates an outline configuration of a plasma
processing apparatus 71 according to the fourth embodiment that
includes a plurality of processing chamber units suitable for
consecutive processing, for example, from depositing a polysilicon
film as a semiconductor active film to depositing a gate insulating
film of top-gate TFTs.
[0451] In this plasma processing apparatus 71, five processing
chamber units, one loading chamber 73, and one unloading chamber 74
are continuously arranged around a substantially heptagonal
transfer chamber 72. The five processing chamber units are plasma
processing chamber units (plasma chambers) 75, 76, and 77, i.e., a
first deposition chamber 75 for depositing an amorphous silicon
film, a second deposition chamber 76 for depositing a silicon oxide
film, and a third deposition chamber 77 for depositing a silicon
nitride film; a laser annealing chamber 78 for annealing a
processed substrate after deposition, and an annealing chamber 79
for performing a heat treatment of the processed substrate.
[0452] The first, second, and third deposition chambers 75, 76, and
77 may be used for depositing different films or for performing the
same treatment based on the same process recipe. Thus, these
deposition chambers have substantially the same configuration.
These plasma chambers 75, 76, and 77 employ first series resonant
frequencies f.sub.0 as radiofrequency characteristics A, and a
variation, defined by relationship 10A, between the maximum
frequency A.sub.max and the minimum frequency A.sub.min, is set to
be less than 0.1:
(A.sub.max-A.sub.min)/(A.sub.max+A.sub.min) (10A)
[0453] The plasma processing chamber units (plasma chambers)
according to this embodiment have the same cross-sectional
configuration as that of the first embodiment shown in FIGS. 1 and
2, and the description thereof is therefore omitted.
[0454] The configuration of the first deposition chamber 75 will be
described as an example.
[0455] The definition and measuring method (see FIGS. 3 to 5) of
the first series resonant frequency f.sub.0 as a radiofrequency
characteristic A of the first deposition chamber 75 are also the
same as those in the first embodiment.
[0456] In the first deposition chamber 75, a frequency three times
the first series resonant frequency f.sub.0 is set to be larger
than the power frequency f.sub.e thatis supplied from a
radiofrequency generator 1.
[0457] With reference to FIG. 3, examples of methods for setting
the first series resonant frequency f.sub.0 are as follows:
[0458] (1) Adjusting the length of the feed plate 3;
[0459] (2) Adjusting the overlap area of the plasma excitation
electrode 4 and the chamber wall 10;
[0460] (3) Adjusting the insulating material between the plasma
excitation electrode 4 and the chamber wall 10; and
[0461] (4) Connecting a conductor between the susceptor electrode 8
and the chamber wall 10.
[0462] In the first deposition chamber 75 of this embodiment, the
power frequency f.sub.e is set to be 40.68 MHz, and the impedance Z
(.OMEGA.) and the phase .theta. (deg) are measured for the
measurement frequency f (MHz) in the range of 0 to 100 MHz to
depict an impedance characteristic curve and a phase curve, as
shown in FIG. 6. The first series resonant frequency f.sub.0 is
then set to be 16.5 MHz so as to satisfy relationship (2):
3f.sub.0>f.sub.e (2)
[0463] In the plasma processing apparatus 71 of this embodiment,
the second deposition chamber 76 and the third deposition chamber
77 have substantially the same structure as that of the first
deposition chamber 75. The first series resonant frequency f.sub.0
as a radiofrequency characteristic A is also set for each of the
second deposition chamber 76 and the third deposition chamber 77,
as in the first deposition chamber 75. More specifically, in each
of these deposition chambers 75 to 77, the first series resonant
frequency f.sub.0 is measured while the power frequency f.sub.e is
set to be 40.68 MHz.
[0464] It is thought that the first series resonant frequency
f.sub.0 is a radiofrequency electrical characteristic which is
determined by many structural factors and which is different in
each apparatus.
[0465] Among the first series resonant frequency f.sub.075 measured
for the first deposition chamber 75, the first series resonant
frequency f.sub.076 measured for the second deposition chamber 76,
and the first series resonant frequency f.sub.077 measured for the
third deposition chamber 77, a variation, defined by relationship
(10), between the maximum frequency f.sub.0max and the minimum
frequency f.sub.0min is set to be less than 0.1:
(f.sub.0max-f.sub.0min)/(f.sub.0max+.sub.0min) (10)
[0466] The variation of the first series resonant frequency f.sub.0
may also be determined by methods (1) to (4) described above.
[0467] In the deposition of the amorphous silicon film, the silicon
oxide film, and the silicon nitride film in the chambers 75, 76,
and 77, respectively, as shown in FIG. 1, a substrate 16 to be
treated is placed on a susceptor electrode 8. A radiofrequency
voltage is applied to both a radiofrequency electrode 4 and the
susceptor electrode 8 from a radiofrequency generator 1, while a
reactive gas is supplied from a gas inlet pipe 17 into a chamber
space 60 through a shower plate 6 to generate a plasma. The target
film is thereby formed on the substrate 16.
[0468] With reference to FIG. 27, the laser annealing chamber 78 is
provided with a laser light source 81 on the upper wall 80 and a
stage 82 for placing the substrate 16 to be treated on the bottom
wall of the chamber. The stage 82 is horizontally movable in the
orthogonal X and Y directions. Spot laser light 83 (shown by chain
lines) is emitted from an aperture 81a of a laser light source 81,
while the stage 82 supporting the substrate 16 horizontally moves
in the X and Y directions so that the laser light 83 scans the
entire surface of the substrate 16. Examples of the laser light
sources 81 are gas lasers using halogen gases, such as XeCl, ArF,
ArCl, and XeF.
[0469] The laser annealing chamber 78 may have any configuration as
long as the spot laser beam from the laser light source can scan
the entire surface of the substrate to be treated. Also, in this
case, gas lasers using halogen gases, such as XeCl, ArF, ArCl, and
XeF can be used as laser light sources. Alternatively, other laser
light sources such as a YAG laser may be employed depending on the
type of the film to be annealed. Laser annealing may be pulsed
laser annealing or continuously oscillating laser annealing. The
annealing chamber may have a configuration of, for example, a
multistage electrical furnace type.
[0470] With reference to FIG. 28, the annealing chamber 79 is of a
multistage electrical furnace type. In the annealing chamber 79, a
plurality of substrates 16 to be treated is placed on heaters 85
which are vertically arranged in the chamber. These heaters 85 are
energized to heat the substrates 16. A gate valve is provided
between the annealing chamber 79 and the transfer chamber 72.
[0471] With reference to FIG. 26, the loading chamber 73 and the
unloading chamber 74 are provided with a loading cassette and a
unloading cassette, respectively, which are detachable from these
chambers. These cassettes can contain a plurality of substrates 16,
that is, the loading cassette contains substrates 16 before a
deposition treatment whereas the unloading cassette contains
substrates 16 after the deposition treatment. A transfer robot 87
as means for transferring the substrates 16 is placed in the
transfer chamber 72 which is surrounded by the processing chamber
unit, the loading chamber 73, and the unloading chamber 74. The
transfer robot 87 is provided with an arm 88 thereon. The arm 88
has an expandable and shrinkable link mechanism and can rotate and
move in the vertical direction. The substrate 16 is supported and
transferred by the end of the arm 88.
[0472] In this plasma processing apparatus 71, the operations of
each component are automatically controlled by a control section,
whereas various processing conditions, such as film deposition
conditions, annealing conditions, and heating conditions, and
process sequences are controlled by an operator. In the operation
of the plasma processing apparatus 71, untreated substrates 16 are
set on the loading cassette, and are transferred from the loading
cassette into each processing chamber by the transfer robot 87
based on the starting operation by the operator. After the
substrates 16 are automatically and sequentially processed in each
chamber, the substrates 16 are placed onto the unloading cassette
by the transfer robot 87.
[0473] In the plasma processing apparatus 71 and the inspection
method in this embodiment, first series resonant frequencies
f.sub.0 of the plasma deposition chambers 75, 76, and 77 are
measured as radiofrequency characteristics at the output terminals
of the matching circuits 2A. A variation between the maximum
frequency f.sub.0max and the minimum frequency f.sub.0min is
defined by relationship (10) as described above and is set to be
less than 0.1. As a result, there are no differences in
radiofrequency electrical characteristics between the deposition
chambers 75, 76 and 77. The impedances of these plasma chambers 75,
76, and 77 can thereby be controlled within a predetermined range.
The effective electrical power consumed in the plasma space is
substantially the same in these plasma chambers 75, 76, and 77.
[0474] Accordingly, substantially the same result is achieved from
a single process recipe for these different plasma chambers 75, 76,
and 77. When films are formed in these plasma chambers 75, 76, and
77, these films can have substantially the same characteristics
(e.g., the same thickness, isolation voltage, and etching rate).
When the variation is controlled to be less than 0.1 under the same
deposition conditions in the plasma chambers 75, 76, and 77, the
variation in film thickness can be controlled to be less than
.+-.5%.
[0475] Thus, a variation in in-plane uniformity of the substrate 16
on the plasma processing caused by the chambers 75, 76, and 77
themselves can be reduced, resulting in high thickness uniformity
of the films.
[0476] In the film processing, such as plasma enhanced CVD and
sputtering, the properties of the resulting films are also
improved. In other words, the same insulating voltage, etching
resistance against etching solutions, and hardness or density of
the film are substantially obtained in the different plasma
chambers 75, 76, and 77.
[0477] Here, the density of the film can be represented by an
etching resistance in a buffered hydrofluoric acid (BHF)
solution.
[0478] Consequently, overall radiofrequency electrical
characteristics of the plasma processing apparatus 71 can be
controlled, resulting in the generation of a highly stable plasma.
In other words, the operations of the individual plasma chambers
75, 76, and 77 of the plasma processing apparatus 71 are uniform
and stable.
[0479] The above-mentioned process does not require a determination
of process conditions by the relationships between enormous amounts
of data on these plasma chambers 75, 76, and 77, and the results
obtained by evaluation of actually processed substrates.
[0480] Thus, in the installation of new systems and the inspection
of installed systems, the time required for obtaining substantially
the same results using the same process recipe in these plasma
chambers 75, 76, and 77 can be significantly reduced by measuring
the first series resonant frequency f.sub.0 as compared with an
inspection method by actual deposition onto the substrate 16 to be
processed. Moreover, according to the inspection method of the
present invention, the plasma processing apparatus 71 can be
directly evaluated in situ in a short period of time, instead of a
two-stage evaluation (i.e., processing of the substrate and
confirmation and evaluation of the operation of the plasma
processing apparatus 71 based on the evaluation of the processed
substrate.) If an inspection process by film deposition on the
substrates 16 is employed in this embodiment, the plurality of
plasma chambers 75, 76, and 77 can be simultaneously evaluated. In
conventional methods, these plasma chambers must be independently
evaluated.
[0481] Accordingly, the inspection method of this embodiment does
not require a shutdown of the production line for several days to
several weeks for operational checking and evaluation of the plasma
processing apparatus 71. Thus, the production line has a high
productivity with reduced expenses for substrates used in the
inspection, processing of these substrates, and labor during the
inspection operations.
[0482] In each of the plasma chambers 75, 76, and 77, a frequency
of three times the first series resonant frequency f.sub.0 is set
to be larger than the power frequency f.sub.e. The overall
radiofrequency electrical characteristics of these plasma chambers
75, 76, and 77 can thereby be controlled within proper ranges.
Since these plasma chambers 75, 76, and 77 exhibit improved
operational stability, electrical power from the radiofrequency
generator 1 can be effectively introduced into the plasma space
between the plasma excitation electrode 4 and the susceptor
electrode 8 when the radiofrequency is higher than 13.56 MHz (which
is used in conventional methods). When the same frequencies as
those in the conventional methods are supplied, the electrical
power is more efficiently consumed in the plasma space as compared
with conventional plasma processing apparatuses.
[0483] As a result, the processing rate is improved by the
higher-frequency plasma excitation. In other words, the deposition
rate of the film is improved in the plasma enhanced CVD or the
like.
[0484] With reference to FIG. 16, the impedance characteristics of
the plasma chambers 75, 76, and 77 can be simultaneously measured
using a fixture in which the ends of a plurality of lead lines 101a
to 101h having the same impedance are connected to a probe clamp
104. Since the impedance is measured by the method shown in the
first embodiment with reference to FIG. 17, the description
therefor is omitted in this embodiment.
[0485] In this embodiment, with reference to FIG. 1, the substrate
16 is placed at the susceptor electrode 8 in each of the plasma
chambers 75, 76, and 77 to set the power frequency f.sub.e and the
first series resonant frequency f.sub.0 for the plasma excitation
electrode 4. The substrate 16 may be placed at the plasma
excitation electrode 4 side.
[0486] Fifth Embodiment
[0487] In accordance with a fifth embodiment of the present
invention, the plasma processing apparatus, the plasma processing
system, and the performance validation system and the inspection
method thereof will now be described with reference to the
drawings.
[0488] FIG. 29 is a cross-sectional view of an outline
configuration of a plasma processing apparatus 91.
[0489] The plasma processing apparatus 91 has a load-lock chamber
93, an annealing chamber 99, and processing chambers 95 and 96
which are provided around a substantially square transfer chamber
(waiting chamber) 92. The transfer chamber 92 contains a transfer
robot for transferring substrates and has gates g1, g2, g3, and g4
at the interfaces to the chambers. The transfer chamber 92, the
annealing chamber 99, and the processing chambers 95 and 96 are
evacuated to high vacuum by individual high-vacuum pumps. The
load-lock chamber 93 is evacuated to low vacuum by a low-vacuum
pump.
[0490] The components of the plasma processing apparatus 91 of this
embodiment correspond to those of the plasma processing apparatus
71 shown in FIGS. 1 to 4, and 26 to 28. The transfer chamber 92
corresponds to the transfer chamber 72, the annealing chamber 99
corresponds to the annealing chamber 79, and the load-lock chamber
93 corresponds to the loading chamber 73 and the unloading chamber
74. The components having the same configurations are not
described.
[0491] The processing chambers (plasma chambers) 95 and 96 have
substantially the same configuration as that of the deposition
chambers 75 and 76 shown in FIGS. 1 to 3 and 26 in the fourth
embodiment and may perform different treatments for forming
different films or the same treatment using the same recipe.
[0492] As shown in FIG. 29, these processing chambers 95 and 96 are
connected to an impedance meter (radiofrequency meter) AN via
switches SW2. In these processing chambers 95 and 96, a variation
between the maximum frequency f.sub.0max and the minimum frequency
f.sub.0min among first series resonant frequencies f.sub.0 is
defined as follows:
(f.sub.0max-f.sub.min)/(f.sub.0max+f.sub.0min) (10)
[0493] Moreover, this variation is set to be less than 0.03.
[0494] An exemplary configuration of the processing chamber 95 will
now be described.
[0495] The cross-sectional view of the processing chamber 95
corresponds to the cross-sectional view shown in FIG. 11 and is the
same as that in the third embodiment. Thus, the configuration will
be described with reference to FIG. 11.
[0496] The processing chamber 95 shown in FIG. 11 is of a
dual-frequency excitation type and is different from the deposition
chamber 75 of the fourth embodiment shown in FIGS. 1 to 3 with
respect to the electrical power supply to the susceptor electrode 8
side, the configurations of a measuring terminal 61 and the
vicinity thereof, and the setting of the first series resonant
frequency f.sub.0. The description of the other corresponding
components referred to with the same reference numerals is
omitted.
[0497] The first series resonant frequency f.sub.0 of each of the
processing chambers 95 and 96 is larger than three times the power
frequency f.sub.e which is supplied from the radiofrequency
generator 1 to the corresponding chamber.
[0498] With reference to FIG. 11, the processing chamber 95 of this
embodiment has a susceptor shield 12 around the susceptor electrode
8. The shaft 13 and the susceptor electrode 8 are electrically
isolated from the susceptor shield 12 by a gap between the
susceptor shield 12 and the susceptor electrode 8 and by insulators
12C provided around the shaft 13. The insulators 12C also serve to
maintain a high vacuum in the chamber space 60. A bellows allows
the susceptor electrode 8 and the susceptor shield 12 to vertically
move so as to adjust the distance between the plasma excitation
electrode 4 and the susceptor electrode 8. The susceptor electrode
8 is connected to a second radiofrequency generator 27 via a feed
plate 28 coupled with the bottom of the shaft 13 and a matching
circuit 25 contained in a matching box 26 at the susceptor
electrode side.
[0499] The feed plate 28 is covered by a chassis 29 connected to
the bottom of a supporting cylinder 12B of the susceptor shield 12,
and the chassis 29 is grounded together with the matching box 26
via a shield wire of a coaxial feed line 27A. The susceptor shield
12, the chassis 29, and the matching box 26 are at the same
potential.
[0500] The matching circuit 25 achieves impedance matching between
the second radiofrequency generator 27 and the susceptor electrode
8. As shown in FIG. 11, the matching circuit 25 includes a tuning
coil 30 and a tuning capacitor 31, which are connected as passive
elements in series between the second radiofrequency generator 27
and the feed plate 28. A load capacitor 32 is connected in parallel
with these passive elements. One end of the load capacitor 32 is
connected to the matching box 26. The matching circuit 25 thereby
has a similar configuration to that of the matching circuit 2A. The
matching box 26 is grounded via a shield line of the feed line 27A,
and one end of the load capacitor 32 is grounded. Another tuning
coil may be connected in series with the tuning coil 30, and
another load capacitor may be connected in parallel with the load
capacitor 32.
[0501] As shown in FIG. 11, an impedance measuring terminal 61 is
connected to an output terminal position PR, which is included in
the region for measuring the impedance in the processing chamber 95
of this embodiment and which corresponds to an output terminal of a
tuning capacitor 24, which is a passive element at the final output
stage among the passive elements of the matching circuit 2A.
[0502] In the vicinity of the output terminal position PR of the
matching circuit 2A, a switch SW1 is provided between the matching
circuit 2A and a feed plate 3, and a switch SW2 is provided between
the impedance meter AN and the feed plate 3, in order to switch
between the matching circuit 2A and the impedance meter AN.
[0503] The impedance characteristic at the output terminal position
PR side of the matching circuit 2A, when the matching circuit 2A is
connected by operation of these switches SW1 and SW2, is set to be
equal to the impedance characteristic from the impedance measuring
terminal 61 side when the impedance meter AN is connected by
operation of these switches. That is, as shown in FIG. 11, the
impedance Z.sub.1 near the switch SW1 is equal to the impedance
Z.sub.2 near the switch SW2.
[0504] Herein, the impedance Z.sub.1 is defined by a portion from
the output terminal position PR of the chassis 21 to a branch point
B for the switch SW2 when the switch SW1 is closed to connect the
matching-circuit 2A and when the switch SW2 is opened, and the
impedance Z.sub.2 is defined by a portion from the impedance
measuring terminal 61 to the branch point B for the switch SW1 when
the switch SW2 is closed to connect the impedance meter AN and when
the switch SW1 is opened.
[0505] A detachable probe for the impedance meter AN is connected
to the impedance measuring terminal 61.
[0506] The impedance from the impedance measuring terminal 61 to
the impedance meter AN when the impedance meter AN is connected by
operation of the switches SW1 and SW2 is set so that the plasma
chamber 95 and the plasma chamber 96 have the same impedance. That
is, the length of the coaxial cable from the impedance measuring
terminal 61 to the impedance meter AN is the same in each of these
plasma chambers.
[0507] In the plasma treatment using the processing chamber 95 of
this embodiment, the switch SW1 is closed and the switch SW2 is
opened. The substrate 16 is placed onto the susceptor electrode 8.
A radiofrequency voltage is applied to both the plasma excitation
electrode 4 and the susceptor electrode 8 through the first
radiofrequency generator 1 and the second radiofrequency generator
27, respectively, while a reactive gas is fed into the chamber
space 60 from the gas inlet pipe 17 through the shower plate 6 to
generate a plasma. The plasma treatment such as film deposition on
the substrate 16 is thereby achieved. Herein, the first
radiofrequency generator 1 supplies a radiofrequency voltage of
13.56 MHz or more (for example, 13.56 MHz, 27.12 MHz, or 40.68
MHz). The second radiofrequency generator 27 supplies a
radiofrequency voltage which is substantially the same as or
different from that of the first radiofrequency generator 1 (for
example, of about 1.6 MHz).
[0508] The first series resonant frequency f.sub.0 as the
radiofrequency characteristic A of the processing chamber 95 in
this embodiment is defined by a measurement like that in the fourth
embodiment, that is, as shown in FIGS. 11 and 30.
[0509] FIG. 30 is an equivalent circuit diagram for measuring the
impedance characteristics of the plasma processing apparatus shown
in FIG. 11. In these drawings, the second radiofrequency generator
27 is depicted. This second radiofrequency generator 27 is not
shown in the state in which power is supplied, but is shown in a
grounded state of the matching circuit 25, because the impedance
characteristics cannot be measured while supplying power.
[0510] In this embodiment, the measuring method of the impedance as
a radiofrequency characteristic, and the procedure for setting the
power frequency f.sub.e and the first series resonant frequency
f.sub.0 so as to satisfy relationship (1) described above, are the
same as those in the third embodiment.
[0511] In the plasma processing apparatus 91 of this embodiment,
the plasma chamber 96 has substantially the same configuration as
that of the processing chamber 95. Also, in the plasma chamber 96,
the first series resonant frequency f.sub.0 is set as in the
processing chamber 95. In detail, in these plasma chambers 95 and
96, the power frequency f.sub.e is set to be 40.68 MHz to measure
the first series resonant frequency f.sub.0. The first series
resonant frequency f.sub.0, however, is a radiofrequency electrical
characteristic which is determined by various factors, such as the
mechanical structure. Thus, it is believed that apparatuses in use
have different first series resonant frequencies f.sub.0.
[0512] Between the first series resonant frequency f.sub.095
measured for the first processing chamber 95 and the first series
resonant frequency f.sub.096 measured for the second plasma chamber
96, a variation, defined by relationship (10), between the maximum
frequency f.sub.0max and the minimum frequency f.sub.0min is set to
be less than 0.03:
(f.sub.0max-f.sub.0min)/(f.sub.0max+f.sub.0min) (10)
[0513] The variation of the first series resonant frequency f.sub.0
may also be determined by methods (1) to (4) described above.
[0514] In each of the plasma chambers 95 and 96, a impedance meter
AN is connected to and disconnected from the impedance measuring
terminal 61 by switching. In a non measuring mode, i.e., in a
plasma generation mode, the switches SW1 and SW2 are operated so
that the impedance meter AN is disconnected from the impedance
measuring terminal 61. The impedance meter AN is thereby not
electrically affected during the plasma generation mode. Using one
impedance meter AN, radiofrequency characteristics of these plasma
chambers 95 and 96 can be measured. The radiofrequency
characteristics A, and particularly first series resonant
frequencies f.sub.0 of the processing chambers 95 and 96, can be
readily measured by measuring the impedance by operating the
switches SW1 and SW2 without disconnecting the impedance meter AN
from the processing chamber 95 or 96.
[0515] In this embodiment, the processing chambers 95 and 96 have
the same radiofrequency characteristic A (impedance Z) between the
branch point B in the vicinity of the measuring point and the
impedance meter AN. Specifically, the processing chambers 95 and 96
have the same impedance Z.sub.2 from the branch point B in the
vicinity of the final stage at the output side of the matching
circuit 2A to the switch SW2 and the same length of coaxial cable
from the switch SW2 to the impedance meter AN.
[0516] In the plasma processing apparatus 91, a gate g0 is opened
to transfer the substrate 16 into the load-lock chamber 93. The
gate g0 is closed to evacuate the load-lock chamber 93 by a
low-vacuum pump. Gates g1 and g2 are opened to transfer the
substrate 16 from the load-lock chamber 93 to the annealing chamber
99 by a transfer arm of a transfer robot in the transfer chamber
92. The gates g1 and g2 are closed to evacuate the transfer chamber
92 and the annealing chamber 99 using a high-vacuum pump. After the
substrate 16 is annealed, the gates g2 and g4 are opened to
transfer the annealed substrate 16 to the processing chamber 95 by
the transfer arm of the transfer robot. After the substrate 16 is
processed in the processing chamber 95, gates g3 and g4 are opened
to transfer the substrate 16 to the plasma chamber 96 by the
transfer arm of the transfer robot in the transfer chamber 92.
After the substrate 16 is processed in the plasma chamber 96, the
gates g1 and g3 are opened to transfer the substrate 16 to the
load-lock chamber 93 by the transfer arm of the transfer robot in
the transfer chamber 92.
[0517] Individual sections are automatically operated by a
controller section. However, the processing conditions such as film
deposition conditions in these processing chambers and the
processing sequence are set by an operator. In the use of this
plasma processing apparatus 91, an untreated substrate 16 is placed
onto a loading cassette in the load-lock chamber 93 and the
operator pushes a start switch. The substrate 16 is sequentially
transferred from the loading cassette to processing chambers by the
transfer robot. After a series of processing steps are performed in
these processing chambers, the substrate 16 is placed into the
unloading (loading) cassette by the transfer robot.
[0518] In these plasma chambers 95 and 96, the substrate 16 is
placed on the susceptor electrode 8, the radiofrequency generator 1
supplies a radiofrequency voltage to both the plasma excitation
electrode 4 and the susceptor electrode 8, while a reactive gas is
fed into the chamber space 60 from the gas inlet pipe 17 via the
shower plate 6 to generate a plasma for forming an amorphous
silicon film, a silicon oxide film, or a silicon nitride film on
the substrate 16, as in the fourth embodiment.
[0519] The plasma processing apparatus 91 and the inspection method
thereof in this embodiment exhibit substantially the same
advantages as those in the fourth embodiment. Moreover, the
variation of the first series resonant frequency f.sub.0 in the
plasma chambers 95 and 96 is set to be less than 0.03. Hence, there
are substantially no differences in radiofrequency electrical
characteristics, such as impedance and resonant frequency, between
the different plasma chambers 95 and 96. Thus, using the impedance
characteristics as references, the operational states of these
plasma chambers can be controlled within a predetermined range. As
a result, the effective electrical power consumed in the plasma
spaces in these plasma chambers 95 and 96 is substantially the
same.
[0520] Accordingly, substantially the same result is achieved from
a single process recipe for these different plasma chambers 95 and
96. When films are formed in these plasma chambers 95 and 96, these
films can have substantially the same characteristics (e.g., the
same thickness, isolation voltage, and etching rate). When the
variation is controlled to be less than 0.03 under the same
deposition conditions in the plasma chambers 95 and 96, the
variation in film thickness can be controlled to be less than
.+-.2%.
[0521] In the plasma processing apparatus 91 of this embodiment,
the impedance measuring terminal 61 is provided at the output
terminal position PR of the matching circuit 2A in each of the
processing chambers 95 and 96, and the impedance meter AN is
detachably connected to the impedance measuring terminal 61.
Moreover, the matching circuit 2A is disconnected from each of the
plasma chambers 95 and 96 by operating the switches SW1 and SW2
when the impedance characteristics of the plasma chambers 95 and 96
are measured, as in the fourth embodiment. Thus, the impedance
characteristics of the plasma chambers 95 and 96 can be measured
without disconnecting the matching circuit 2A from the power supply
line. Accordingly, the impedance characteristics of the plasma
chambers 95 and 96 can be readily measured, improving the
processing efficiency during measuring the first series resonant
frequency f.sub.0.
[0522] Since the impedance Z.sub.1 is equal to the impedance
Z.sub.2 in these plasma chambers 95 and 96, switching between the
measuring mode of the impedance characteristics and the first
series resonant frequency f.sub.0, and the operational mode of the
plasma processing apparatus can be readily performed by only
operating the switches SW1 and SW2, i.e., without connecting and
disconnecting the matching circuit 2A and a probe 105 for measuring
the impedance shown in FIG. 16. Thus, the measurements of the first
series resonant frequencies f.sub.0 of these plasma chambers 95 and
96 can be efficiently performed by operating the switches SW1 and
SW2.
[0523] In addition, the radiofrequency characteristic A (impedance
Z) between the branch point B near the measuring point and the
impedance meter AN (including the impedance measuring terminal 61
and the switch SW2) is the same in the plasma chambers 95 and 96.
Since the impedance measured by the impedance meter AN connected to
each impedance measuring terminal 61 is regarded as the impedance
measured at the output terminal position PR at the final stage at
the output side of the matching circuit 2A in these plasma chambers
95 and 96, no correction is required for calculating the first
series resonant frequency f.sub.0 in each plasma chamber. Thus, the
first series resonant frequency f.sub.0 can be exactly measured
with improved efficiency and without performing correction of the
observed value.
[0524] Moreover, the first series resonant frequency f.sub.0, and
the power frequency f.sub.e are set in each of the plasma chambers
95 and 96. Since the frequency characteristics of the electrodes 4
and 8 for generating the plasma are directly defined, electrical
power can be more efficiently consumed in the plasma generating
space. Accordingly, the plasma processing efficiency is further
improved in the overall plasma processing apparatus 91.
[0525] In this embodiment, the two switches SW1 and SW2 are
provided. Since the essential feature in this embodiment is that
the impedance from the branch point B to the output terminal
position PR is equal to the impedance from the branch point B to
the probe, this requirement may be satisfied using one switch.
[0526] As shown in FIG. 32, instead of the switches SW1 and SW2 of
the plasma chambers 95 and 96, switching between the plasma
chambers to be measured may be performed by using a common switch
SW4.
[0527] In this embodiment, the power frequency f.sub.e and the
first series resonant frequency f.sub.0 are set for the plasma
excitation electrode 4. However, the frequencies may instead be set
for the susceptor electrode 8. In such a case, as shown in FIG. 11,
an output terminal position PR' of the matching circuit 25 is
defined for determining the region for measuring the impedance.
[0528] In addition to the apparatus having the parallel plate
electrodes 4 and 8, this embodiment is also applicable to plasma
processing apparatuses of an inductive coupled plasma (ICP)
excitation type and a radial line slot antenna (RLSA) type and
processing apparatuses such as a reactive ion etching apparatus and
a reactive sputtering etching apparatus.
[0529] Plasma sputtering may be achieved by using a target material
instead of the electrodes 4 and 8.
[0530] Sixth Embodiment
[0531] In accordance with a sixth embodiment of the present
invention, the plasma processing apparatus, the plasma processing
system, and the performance validation system and the inspection
method thereof will now be described with reference to the
drawings.
[0532] FIG. 31 is a schematic view of an outline configuration of a
plasma processing system of this embodiment.
[0533] The plasma processing system of this embodiment is
substantially a combination of plasma processing apparatuses 71 and
71' corresponding to that shown in FIG. 26 according to the fourth
embodiment, and a plasma processing apparatus 91 corresponding to
that shown in FIG. 29 according to the fifth embodiment. Components
having the same functions as in the fourth and fifth embodiments
are referred to with the same reference numerals, and a detailed
description thereof with reference to drawings has been
omitted.
[0534] As shown in FIG. 31, the plasma processing system of this
embodiment constitutes a part of a production line which includes
the plasma processing apparatus 71, the plasma processing apparatus
91, and the plasma processing apparatus 71'. The plasma processing
apparatus 71 has three dual-frequency plasma processing chamber
units (plasma chambers) 95, 96, and 97 shown in FIG. 29 (according
to the fifth embodiment), instead of the plasma processing chamber
units (plasma chambers) 75, 76, and 77 shown in FIG. 26 (according
to the fourth embodiment). The plasma processing apparatus 91 has
two plasma processing chamber units (plasma chambers) 95 and 96.
The plasma processing apparatus 71' has the three dual-frequency
plasma processing chamber units (plasma chambers) 95, 96, and 97.
These plasma processing chamber units (plasma chambers) 95, 96, and
97 in the plasma processing apparatuses 71, 71', and 91 have
substantially the same configuration.
[0535] Impedance measuring terminals, which correspond to the
impedance measuring terminal 61 shown in FIG. 11, of the plasma
chambers 95, 96, and 97 are connected to an impedance meter AN via
a switch SW3. In the measurement of the impedance, the switch SW3
connects only one of the plasma chambers 95, 96, and 97 to the
impedance meter AN. Coaxial cables have the same length between the
impedance measuring terminals of the plasma chambers 95, 96, and 97
and the switch SW3 so that the impedances from these impedance
measuring terminals to the switch SW3 are the same. A detachable
probe of an impedance meter AN is connected to the impedance
measuring terminal, as in the fifth embodiment shown in FIG.
11.
[0536] The first series resonant frequency f.sub.0 of each of the
plasma chambers 95, 96, and 97 is measured as in the fifth
embodiment by operating the switch SW3, and is set to be, for
example, 123.78 MHz for a power frequency f.sub.e of 40.68 MHz so
as to satisfy inequality (4):
f.sub.0>3f.sub.e (4)
[0537] Among the first series resonant frequencies f.sub.0 measured
for the plasma chambers 95, 96, and 97, a variation, defined by
relationship (10), between the maximum frequency f.sub.0max and the
minimum frequency f.sub.0min is set to be less than 0.03, as in the
fifth embodiment:
(f.sub.0max-f.sub.0min)/(f.sub.0max+f.sub.0min) (10)
[0538] Furthermore, in this embodiment, the series resonant
frequency f.sub.0' defined by a plasma electrode capacitance
C.sub.e between the plasma excitation electrode 4 and the susceptor
electrode 8 is set to be larger than three times the power
frequency f.sub.e:
f.sub.0'>3f.sub.e (5)
[0539] In addition, the series resonant frequency f.sub.0' may be
larger than the square root of the power frequency f.sub.e
(=interelectrode distance d/distance .delta. of plasma nonemitting
portion) so that the series resonant frequency f.sub.0' defined by
the plasma electrode capacitance C.sub.e and the power frequency
f.sub.e satisfy relationship (1), as described in the fifth
embodiment.
[0540] In the plasma processing system of the present invention,
for example, a substrate 16, which has been preliminarily treated,
is subjected to a first film deposition treatment in the plasma
chambers 95, 96, and 97 of the plasma processing apparatus 71, is
annealed in the annealing chamber 79, and is annealed in the laser
annealing chamber 78. The treated substrate 16 is transferred from
the plasma processing apparatus 71 and is subjected to second and
third film deposition treatments in plasma processing chambers (not
shown in the drawing), which are substantially the same as those of
the plasma processing apparatus 71.
[0541] The substrate is transferred from this plasma processing
apparatus and a photoresist is applied thereto by a
photolithographic step using another apparatus (not shown).
[0542] The substrate 16 is transferred into the plasma processing
apparatus 91 and is plasma-etched in the processing chambers 95 and
96. Next, the substrate 16 is transferred from the plasma
processing apparatus 91 and is subjected to a film deposition
treatment in a plasma chamber (not shown) which is substantially
the same as the plasma processing apparatus 91.
[0543] The substrate 16 is transferred from the plasma processing
apparatus (not shown in the drawing). After the resist is removed,
the substrate 16 is subjected to photolithographic patterning in
another apparatus not shown in the drawing.
[0544] Finally, the substrate 16 is subjected to first, second, and
third deposition treatments in the plasma chambers 95, 96, and 97
of the plasma processing apparatus 71', and is transferred to the
subsequent step to complete the steps in the plasma processing
system according to this embodiment.
[0545] The plasma processing system and the inspection method of
this embodiment exhibit the same advantages as those in the fourth
and fifth embodiments. Moreover, the variation between the maximum
frequency f.sub.0max and the minimum frequency f.sub.0min among the
first series resonant frequencies f.sub.0 of the plasma chambers
95, 96, and 97 is set to be less than 0.03 so that there are no
differences in radiofrequency electrical characteristics between
the plasma chambers 95, 96, and 97 of the plasma processing
apparatuses 71, 91, and 71'. The states of these plasma chambers
95, 96, and 97 can therefore be controlled to be within a
predetermined control range defined by the impedance
characteristics of the overall plasma processing system. Thus,
these plasma chambers 95, 96, and 97 have substantially the same
plasma density.
[0546] Accordingly, substantially the same result is achieved from
a single process recipe for these different plasma chambers 95, 96,
and 97 in the overall plasma processing system. When films are
formed in these plasma chambers 95, 96, and 97, these films can
have substantially the same characteristics (e.g., the same
thickness, isolation voltage, and etching rate). When the variation
is controlled to be less than 0.03 under the same deposition
conditions in the plasma chambers 95, 96, and 97, the variation in
film thickness can be controlled to be less than .+-.2%.
[0547] Consequently, overall radiofrequency electrical
characteristics of the plasma processing system can be controlled,
resulting in the generation of a highly stable plasma in each of
the plasma chambers 95, 96, and 97. In other words, the operations
of the individual plasma chambers 95, 96, and 97 of the plasma
processing system are uniform and stable.
[0548] The above-mentioned process does not require a determination
of the process conditions based on the relationships between
enormous amounts of data for these plasma chambers 95, 96, and 97,
and the results obtained by evaluation of actually processed
substrates.
[0549] Thus, in the installation of new systems and the inspection
of installed systems, the time required for obtaining substantially
the same results using the same process recipe in these plasma
chambers 95, 96, and 97 can be significantly reduced by measuring
the first series resonant frequency f.sub.0 as compared with an
inspection process by actual deposition onto the substrates 16 to
be processed. Moreover, according to the inspection method of the
present invention, the plasma processing system can be directly
evaluated in situ in a short period of time, instead of a two-stage
evaluation (i.e., processing of the substrate, and confirmation and
evaluation of the operation of the plasma processing system based
on the evaluation of the processed substrate). If an inspection
process by film deposition on the substrates 16 is employed in this
embodiment, the plurality of plasma chambers 95, 96, and 97 can be
simultaneously evaluated. In conventional methods, these plasma
chambers must be independently evaluated.
[0550] Accordingly, the inspection method of this embodiment does
not require a shutdown of the production line for several days to
several weeks for operational checking and evaluation of the plasma
processing system. Thus, the production line has a high
productivity and reduces the cost of substrates used in the
inspection, processing of these substrates, and labor during the
inspection operations.
[0551] In each of the plasma chambers 95, 96, and 97, a frequency
of three times the first series resonant frequency f.sub.0 is set
to be larger than the power frequency f.sub.e. The overall
radiofrequency electrical characteristics of these plasma chambers
95, 96, and 97 can thereby be controlled within proper ranges.
Since these plasma chambers 95, 96, and 97 exhibit improved
operational stability, electrical power from the radiofrequency
generator can be effectively introduced into the plasma space
between the plasma excitation electrode 4 and the susceptor
electrode 8, even if the radiofrequency is higher than 13.56 MHz
(which is used in conventional methods). When the same frequencies
as those in the conventional methods are supplied, the electrical
power is more efficiently consumed in the plasma space compared
with conventional plasma processing apparatuses.
[0552] As a result, the processing rate is improved by the
higher-frequency plasma excitation. In other words, the deposition
rate of the film is improved in the plasma enhanced CVD or the
like. Since the generation of the plasma is stabilized in all the
plasma chambers 95, 96, and 97, the individual plasma processing
apparatuses 71, 91, and 71' also have a high operational stability.
Accordingly, the plasma processing system has a high operational
stability.
[0553] Thus, variation in the in-plane uniformity of the substrate
16 on the plasma processing caused by the chambers 95, 96, and 97
themselves can be reduced, resulting in a high thickness uniformity
of the films. In the film processing, such as plasma enhanced CVD
and sputtering, the properties of the resulting films are also
improved, and substantially the same insulating voltage, etching
resistance against etching solutions, and hardness or density of
the film are obtained from the different plasma chambers.
[0554] When the applied frequency is the same, the plasma density
in this embodiment can be increased as compared with a conventional
plasma processing system. Thus, a film having a desired thickness
can be deposited by reduced input electrical powder at a processing
rate which is the same as that of the conventional system. Since
this advantage is applicable to the plasma chambers 95, 96, and 97,
the overall plasma processing system exhibits a reduced electrical
loss, a reduced operating cost, and an enhanced productivity. Since
the film can be deposited in a reduced amount of time, the
electrical power consumption for plasma processing can be
reduced.
[0555] In the plasma processing system of this embodiment, the
series resonant frequency f.sub.0' and the power frequency f.sub.e
are set for each plasma chamber 95, 96, or 97. Since the frequency
characteristics of the electrodes 4 and 8 for emitting the plasma
are directly determined, electrical power can be more efficiently
supplied to the plasma space in each plasma chamber 95, 96, or 97.
Thus, the plasma processing system exhibits further improved power
consumption efficiency and processing efficiency.
[0556] In the plasma processing system of this embodiment, the
impedance measuring terminal is provided at the output terminal
position PR of the matching circuit 2A in each of the processing
chambers 95, 96, and 97, and the impedance meter AN is detachably
connected to the impedance measuring terminal. Moreover, the
matching circuit 2A is disconnected from each of the plasma
chambers 95, 96, and 97 by operating the switch SW3 when the
impedance characteristics of the plasma chambers 95, 96, and 97 are
measured, as in the fourth embodiment. Thus, the impedance
characteristics of the plasma chambers 95, 96, and 97 can be
measured without disconnecting the matching circuit 2A from the
power supply line. Accordingly, the impedance and resonant
frequency characteristics of the plasma chambers 95, 96, and 97 can
be readily.
[0557] Thus, a probe can be readily connected to the impedance
measuring terminal 61 when the impedance characteristics of the
plasma chambers 95, 96, and 97 are measured, improving the
measuring efficiency for the first series resonant frequency
f.sub.0. The impedance characteristics and the first series
resonant frequency f.sub.0 can be readily determined only by
operating the switches SW1 and SW2, without disconnecting the
matching circuit 2A from the plasma chambers 95, 96, and 97, and
without disconnecting the probe 105 for measuring the
impedance.
[0558] Moreover, as shown in FIG. 11, the impedance Z.sub.1 is
equal to the impedance Z.sub.2, and the impedance from the
impedance measuring terminal 61 to the switch SW3 shown in FIG. 31)
is equal in the plasma chambers 95, 96, and 97 of the plasma
processing apparatuses 71, 71', and 91. Thus, by operating the
switches SW1, SW2, and SW3, the impedance observed by the impedance
meter AN connected to the impedance measuring terminal 61 can be
regarded as the same as the impedance observed at the output
terminal position PR at the final stage at the output side of the
matching circuit 2A.
[0559] Since there are no differences in impedance characteristics
from the impedance measuring terminal 61 to the switch SW3 among
the plasma chambers 95, 96, and 97, no correction is required for
calculation of the first series resonant frequency f.sub.0 for each
plasma chamber 95, 96, or 97 of the plasma processing apparatuses
71, 71', and 91. Since the observed values are not corrected, the
resonant frequency characteristics of the plasma processing system
can be set with a high operation efficiency, and the first series
resonant frequency f.sub.0 can be more precisely measured.
[0560] In this embodiment, the switches SW1, SW2, and SW3 may
cooperate with switching of the plasma chambers 95, 96, and 97. The
two switches SW1 and SW2 may be integrated into one switch in which
the impedance from the branch point to the output terminal position
PR is equal to the impedance from the branch point to the
probe.
[0561] In this embodiment, the power frequency f.sub.e and the
first series resonant frequency f.sub.0 for the plasma excitation
electrode 4 are set. However, the frequencies for the susceptor
electrode 8 may be set instead. In such a case, as shown in FIG.
11, an output terminal position PR' of the matching circuit 25 is
determined for defining the region for measuring the impedance.
[0562] In addition to the apparatus having the parallel plate
electrodes 4 and 8, this embodiment is also applicable to plasma
processing apparatuses of inductive coupled plasma (ICP) excitation
types and radial line slot antenna (RLSA) types, and processing
apparatuses such as reactive ion etching apparatuses and reactive
sputtering etching apparatuses.
[0563] In this embodiment, as shown in FIG. 32, each of the plasma
chambers (plasma processing chamber units) 95, 96, and 97 is
provided with a matching circuit 2A and a radiofrequency generator,
and an impedance meter AN is connected to a coupler of the matching
circuit 2A via a switch SW4. As shown in FIG. 33, matching circuits
2A of the plasma chambers 95, 96, and 97 may be connected to the
same radiofrequency generator 1 by switching. Alternatively, as
shown in FIG. 34, the plasma chambers 95, 96, and 97 may be
connected to the same matching circuit 2A by switching. In this
case, as shown in FIG. 33, the impedance meter AN is connected to
couplers between the plasma chambers 95, 96, and 97 and the
matching circuit 2A via the switch SW4.
[0564] In this embodiment, the first series resonant frequency
f.sub.0, as a radiofrequency characteristic A, is set according to
relationship (10) described above. Alternatively, the
radiofrequency characteristic A may be a resonant frequency f; or
an impedance Z.sub.e, a resistance R.sub.e, or a reactance X.sub.e
at the frequency of the radiofrequency waves; and the variation
thereof may be defined by relationship (10A) described above. Since
the above characteristics of these plasma chambers 95, 96, and 97
are controlled to be within a predetermined range, there are no
differences in radiofrequency electrical characteristics between
these plasma chambers 95, 96, and 97. Thus, the effective
electrical power consumed in the plasma spaces in the plasma
chambers 95, 96, and 97 is substantially the same.
[0565] When the impedance Z.sub.e at the plasma excitation
frequency is employed as the radiofrequency characteristic A, it is
not necessary to find the dependence of the radiofrequency
characteristic on the frequency in the plasma chambers 95, 96, and
97. Thus, the impedance Z.sub.e can be readily determined as
compared with the resonant frequency f which must be determined by
the dependence of Z and .theta. on the frequency. Moreover, the
impedance Z can directly reflect the radiofrequency electrical
characteristic at the plasma excitation frequency of the plasma
chambers 95, 96, and 97.
[0566] When the resistance R.sub.e or the reactance X.sub.e is
employed, this can more directly reflect the radiofrequency
electrical characteristic at the plasma excitation frequency of the
plasma chamber as compared with the impedance Z.sub.e which
corresponds to the vector defined by the resistance R.sub.e and the
reactance X.sub.e.
[0567] Seventh Embodiment
[0568] In accordance with a seventh embodiment of the present
invention, the plasma processing apparatus, the plasma processing
system, and the performance validation system and the inspection
method thereof will now be described with reference to the
drawings.
[0569] FIG. 35 is a schematic view of an outline configuration of a
plasma processing unit (plasma chamber) of this embodiment.
[0570] This embodiment differs from the fourth to sixth embodiments
with respect to the region for measuring the frequency
characteristics, the measuring terminal, the switches, and the
plasma processing unit (plasma chamber). The configuration of the
plasma processing apparatus and the configuration of the plasma
processing system are the same as those according to the fourth to
sixth embodiments. Components having the same functions as in the
fourth to sixth embodiments are referred to with the same reference
numerals, and a detailed description thereof with reference to
drawings has been omitted.
[0571] In this embodiment, the plasma chamber is of a
dual-frequency type, as in the second embodiment. With reference to
FIG. 35, a measuring point PR3 defining the region for measuring
the radiofrequency characteristic A is set at an input terminal
position of a matching circuit 2A, which is connected to a
radiofrequency generator 1 via a radiofrequency feed line 1A in
each plasma chamber 75, 76, 77, 95, 96, or 97. The measuring point
PR3 for measuring the radiofrequency characteristic A of the plasma
chamber is connected to a switch SW5. The switch SW5 operates the
connection and disconnection of the plasma chamber to the
radiofrequency generator 1 via the radiofrequency feed line 1A in a
plasma generation mode, and to the radiofrequency measuring meter
(impedance meter AN) via a connecting line 61A in a radiofrequency
measuring mode.
[0572] Here, the impedance from the measuring point PR3 to the
radiofrequency generator 1 via the radiofrequency feed line 1A is
equal to the impedance from the measuring point PR3 to the
impedance meter AN via the connecting line 61A. In other words, the
radiofrequency feed line 1A and the connecting line 61A have the
same length. The radiofrequency characteristics A, and particularly
the first series resonant frequency f.sub.0 by measuring the
impedance etc., can be readily measured simply by operating the
switch SW5, without disconnecting the impedance meter AN from the
plasma chamber.
[0573] Herein, the first series resonant frequency f.sub.0 as the
radiofrequency characteristic A in the plasma chamber of this
embodiment is defined by a measurement, as in the fourth to sixth
embodiments. That is, the first series resonant frequency f.sub.0
in this embodiment is defined by a measurement, as shown in FIGS.
36 and 37.
[0574] FIGS. 36 is a schematic view for illustrating the impedance
characteristics of the plasma chamber of this embodiment. FIG. 37
is an equivalent circuit diagram of the plasma chamber shown in
FIG. 36 for measuring the impedance characteristics.
[0575] As shown in FIG. 36, possible radiofrequency electrical
factors affecting the first series resonant frequency f.sub.0 among
radiofrequency characteristics A which are measured within the
above-described range are as follows:
[0576] Contribution from the connecting line 61A;
[0577] Inductance L.sub.SW and resistance R.sub.SW of the switch
SW5;
[0578] Contribution from the matching circuit 2A;
[0579] Inductance L.sub.f and resistance R.sub.f of the feed plate
3;
[0580] Plasma electrode capacitance C.sub.e between the plasma
excitation electrode 4 and the susceptor electrode 8;
[0581] Capacitance C.sub.S between the susceptor electrode 8 and
the susceptor shield 12;
[0582] Inductance L.sub.C and resistance R.sub.C of the supporting
cylinder 12B of the susceptor shield 12;
[0583] Inductance L.sub.B and resistance R.sub.B of a bellows
11;
[0584] Inductance L.sub.A and resistance R.sub.B of the chamber
wall 10;
[0585] Capacitance C.sub.A between the gas inlet pipe 17 and the
plasma excitation electrode 4 which sandwich an insulator 17a;
[0586] Capacitance C.sub.B between the plasma excitation electrode
4 and the chassis 21; and
[0587] Capacitance C.sub.C between the plasma excitation electrode
4 and the chamber wall 10.
[0588] It is considered that these radiofrequency electrical
factors constitute a circuit which conducts a radiofrequency
current supplied in a plasma emitting mode, as shown in FIG. 37.
That is, in this equivalent diagram, the contribution from the
connecting line 61A, the inductance L.sub.SW and resistance
R.sub.SW of the switch SW5, the contribution from the matching
circuit 2A, the inductance L.sub.f and resistance R.sub.f of the
feed plate 3, the plasma electrode capacitance C.sub.e between the
plasma excitation electrode 4 and the susceptor electrode 8, the
capacitance C.sub.S between the susceptor electrode 8 and the
susceptor shield 12, the inductance L.sub.C and resistance R.sub.C
of the supporting cylinder 12B of the susceptor shield 12, the
inductance L.sub.B and resistance R.sub.B of the bellows 11, and
the inductance L.sub.A and resistance R.sub.B of the chamber wall
10 are connected in series in that order, with the terminal of the
resistance R.sub.A being grounded. Moreover, the capacitance
C.sub.A, the capacitance C.sub.B, and the capacitance C.sub.C are
connected in parallel between the resistance R.sub.f and the plasma
electrode capacitance C.sub.e, with one end of each capacitance
being grounded. The first series resonant frequency f.sub.0 can be
defined by measuring the impedance of this equivalent circuit.
[0589] The first series resonant frequency f.sub.0 defined in such
a manner is determined in the same way as shown in the fourth to
sixth embodiments. Among the first series resonant frequencies
f.sub.0 of the individual plasma chambers, a variation of the first
series resonant frequencies f.sub.0 of the plasma chambers is
defined by relationship (10) using the maximum frequency f.sub.0max
and the minimum frequency f.sub.0min, and is set to be less than
0.03. The variation of the first series resonant frequencies
f.sub.0 can be set by methods (1) to (4) described above, and by
the following methods (5) to (7):
[0590] (5) Selecting load capacitors 22 substantially having the
same characteristics;
[0591] (6) Selecting tuning capacitors 24 substantially having the
same characteristics; and
[0592] (7) Adjusting the shapes (size, number of turns, and length)
of tuning coils 23.
[0593] The plasma processing apparatus or system, and the
inspection method of this embodiment, exhibit the same advantages
as those in the fourth and sixth embodiments. Moreover, by
including the matching circuit 2A in the region for the
radiofrequency characteristics, there are no differences in
radiofrequency electrical characteristics between the plasma
chambers 75, 76, 77, 95, 96, and 97, in addition to the chamber
space 60. Thus, the effective electrical powers consumed in the
plasma spaces in the plasma chambers 75, 76, 77, 95, 96, and 97 can
be equalized. By incorporating the matching circuit 2A, the same
plasma processing results are obtainable from the same process
recipe.
[0594] In this embodiment, the length of the radiofrequency feed
line 1A is equal to the length of the connecting line 61A. Thus,
the radiofrequency characteristic A of the chamber space 60
measured at the output terminal position PR2 of the radiofrequency
generator 1 when the switch SW5 electrically disconnects the
measuring point PR3 from the radiofrequency measuring meter AN and
electrically connects the matching circuit 2A to the radiofrequency
generator 1 is equal to the radiofrequency characteristic A of the
chamber space 60 measured at an output terminal position PR2' of
the impedance meter AN when the switch SW5 electrically connects
the measuring point PR3 to the impedance meter AN and electrically
disconnects the matching circuit 2A from the radiofrequency
generator 1.
[0595] Thus, in this embodiment, the measured radiofrequency
characteristic is substantially the same as the radiofrequency
characteristic A of the plasma chamber which is measured at the
output terminal position PR2 of the radiofrequency feed line 1A
connected to the radiofrequency generator 1, as shown in FIGS. 35,
36, and 37. By such determination of the region for measuring the
radiofrequency characteristic A, the different plasma chambers 75,
76, 77, 95, 96, and 97 exhibit substantially the same
radiofrequency electrical characteristics of the chamber space 60,
including the matching circuit 2A and the radiofrequency feed line
1A, as compared with a case in which the region for measuring the
radiofrequency characteristic A does not include the matching
circuit 2A and the radiofrequency feed line 1A. Thus, these plasma
chambers 75, 76, 77, 95, 96, and 97 consume substantially the same
effective electrical power in the plasma spaces. Accordingly,
substantially the same result is achieved from a single process
recipe for these different plasma chambers, as compared with a case
in which the region for measuring the electric characteristic does
not include the matching circuit 2A and the radiofrequency feed
line 1A.
[0596] With reference to FIGS. 1 and 11, the region for measuring
the radiofrequency characteristics in the fourth to sixth
embodiments may be set at the measuring point PR3 or the measuring
point PR2.
[0597] As shown in FIG. 40, the region for measuring the
radiofrequency characteristics may be defined by the output
terminal position PR2 of the radiofrequency generator 1. That is,
the radiofrequency generator 1 is disconnected from the
radiofrequency feed line 1A at the output terminal position
PR2.
[0598] Alternatively, the region may be defined by the measuring
point PR3 at the input terminal of the matching circuit 2A. That
is, the radiofrequency generator 1 and the radiofrequency feed line
1A are disconnected from the matching circuit 2A at the measuring
point PR3.
[0599] Another embodiment of the performance validation system of
the plasma processing apparatus or the plasma processing system in
accordance with the present invention will now be described with
reference to the drawings.
[0600] The configuration of this system is the same as that shown
in FIG. 20, and the method for using this system is the same as
that described with reference to FIGS. 21 to 24. Thus, the
description thereof is omitted.
[0601] With reference to FIG. 23, a specifications page includes an
apparatus section K6 for displaying a selected apparatus, a vacuum
performance section K7, a gas supply and discharge performance
section K8, a temperature performance section K9, and an electrical
performance section K10 of the plasma processing chamber. These
sections correspond to "standard performance information" of the
plasma chamber of the selected apparatus.
[0602] The following items are described in these sections. In the
vacuum performance section K7:
[0603] final degree of vacuum: 1.times.10.sup.-4 Pa or less,
and
[0604] operational pressure: 30 to 300 Pa. In the gas supply and
discharge performance section K8:
[0605] maximum gas flow rates:
5 SiH.sub.4 100 SCCM, NH.sub.3 500 SCCM, N.sub.2 2,000 SCCM, and
discharge property: 20 Pa or less at a flow of 500 SCCM.
[0606] In the temperature performance section K9:
[0607] heater temperature: 200 to 350.+-.10.degree. C., and
[0608] chamber temperature: 60 to 80.+-.2.0.degree. C.
[0609] Herein, SCCM (standard cubic centimeters per minute)
represents a gas flow rate which is converted to standard
conditions (0.degree. C. and 1013 hPa) and the unit thereof
corresponds to cm.sup.3/min.
[0610] For each parameter P, the variation between the maximum
P.sub.max and the minimum P.sub.min in different plasma chambers of
a plasma processing apparatus or a plasma processing system is
defined by relationship (10B):
(P.sub.max-P.sub.min)/(P.sub.max+P.sub.min) (10B)
[0611] This variation is displayed with a standard range (a maximum
and a minimum) of each parameter of each plasma processing
apparatus or plasma processing system.
[0612] The electrical performance section K10 of the plasma
processing chamber includes the description of the first series
resonant frequency f.sub.0 described in the fourth to seventh
embodiments, and the relationship between this value and the power
frequency f.sub.e. This section K10 further includes the
description of the resistance R.sub.e and the reactance X.sub.e at
the power frequency f.sub.e of the plasma chamber, the plasma
capacitance C.sub.0 between the plasma excitation electrode 4 and
the susceptor electrode 8, and the loss capacitance C.sub.X between
the plasma excitation electrode 4 and each position lying at the
grounded potential of the plasma chamber. The specifications page
CP1 includes a description for certifying the performance, that is,
"it is certified that these parameters were within the ranges
described in this page when the plasma processing apparatus or the
plasma processing system was supplied".
[0613] Thus, overall radiofrequency electrical characteristics of
the plasma processing apparatus or the plasma processing system and
variations in electrical characteristics of the plasma chambers can
be provided as novel references when it is distributed. A
customer's terminal C1 or an engineer's terminal C2 can print out
the performance information to make a hard copy that can be used as
a catalog or specifications including the performance information.
The values of the first series resonant frequency f.sub.0, the
resistance R.sub.e, the reactance X.sub.e, and the capacitances
C.sub.0 and C.sub.X, and the certification statements are displayed
on the customer's terminal C1 or the engineer's terminal C2, or are
described in the catalog or specifications so that the customer can
make a purchasing decision based on an estimation of the plasma
chamber performance as opposed to actually examining the electrical
components.
[0614] With reference to FIG. 20, the server S waits for a display
request for the next subpage (Step S 3 in FIG. 21) until the
log-off request from the customer's terminal C1 is received (Step
S5) after a subpage is transmitted to the customer's terminal C1,
and completes the communication with the customer's terminal C1
when the log-off request is received from the customer's terminal
C1.
[0615] The customer who purchases a plasma processing apparatus or
plasma processing system from the maintenance engineer can access
the sever S to browse the contents of the "performance information"
of the purchased apparatus or system.
[0616] With reference to FIG. 24, when the customer and the
maintenance engineer conclude an agreement of sale, the maintenance
engineer provides a serial number of the plasma processing
apparatus or plasma processing system, a customer ID which
corresponds to the serial number, and a customer password (browsing
password) which allow the customer to browse the "operation and
maintenance information" of the plasma processing apparatus or
plasma processing system and individual plasma chambers
thereof.
[0617] With reference to FIG. 22, when the customer accesses the
server, the customer operates a customer button K5 in the catalog
page CP to submit the display request for the customer screen to
the server S.
[0618] When receiving the display request (Step S3-B), the server S
submits a subpage for prompting the customer's terminal C1 to input
a "customer password" (Step S6). FIG. 24 shows a customer page CP2
including a customer ID input box K11 and a password input box
K12.
[0619] The customer page CP2 for the input request is displayed on
the display of the customer's terminal C1, and the customer's
terminal C1 inputs a "customer password" and a "customer ID", which
were previously provided, in order to identify the plasma
processing apparatus or plasma processing system and the individual
plasma chambers thereof.
[0620] As shown in FIG. 24, the customer inputs a customer ID and a
password in the customer ID input box K11 and the password input
box K12, respectively. When the server S receives the authorized
"customer ID" and "customer password" from the customer's terminal
C1 (Step S7), the server S transmits to the customer's terminal C1
the "operation and maintenance information" subpage that pertains
to the "customer password" (Step S9).
[0621] That is, browsing of the "operation and maintenance
information" is permitted by the authorized customer who concludes
the agreement of sale on the plasma processing apparatus or plasma
processing system and who knows the correct "password". Thus, no
third party can obtain the "operation and maintenance information"
by accessing the server S. In general, the maintenance engineer
concludes agreements of sale with many customers and distributes a
plurality of plasma processing apparatuses and plasma processing
systems to these customers. A "customer password" is provided for
each of the plasma processing apparatuses or plasma processing
systems and the plasma chambers thereof to the corresponding
customer. Thus, the customer can browse the "operation and
maintenance information" which relates to the "customer password"
and which corresponds to the purchased plasma processing apparatus
or plasma processing system and the plasma chambers thereof.
[0622] This system can effectively prevent confidential information
from being disclosed to other customers, and can identify a
plurality of plasma processing apparatuses or systems and the
plasma chambers thereof which are purchased by the same customer.
When the authorized "customer password" is not received (Step S7),
the server S transmits a reject message to the customer's terminal
C1 (Step S8) to prompt the customer to reinput a "customer
password". When the customer inputs the authorized "customer
password", the customer can browse the "operation and maintenance
information".
[0623] When the ID and password are authorized (Step S7), the
server retrieves a subpage which corresponds to the requested
information from a database D and transmits the information to the
customer. In detail, the server S retrieves data such as "vacuum
performance", "gas supply and discharge performance", "temperature
performance", and "electrical performance" from the database D
based on the requests to display the "standard performance
information" or the "operation and maintenance information" on the
plasma processing apparatus or plasma processing system and the
plasma chambers thereof which are identified by the customer ID,
and transmits a specifications page including this data (Step
S9).
[0624] FIG. 38 shows an "operation and maintenance information"
subpage CP3 which is transmitted to the customer's terminal C1 from
the server S. The maintenance history page CP3 includes a serial
number display section K13 for displaying the serial number of the
purchased plasma processing apparatus or plasma processing system
and the plasma chambers thereof, the vacuum performance section K7,
the gas supply and discharge performance section K8, the
temperature performance section K9, the electrical performance
section K10 of the plasma processing chamber. These sections
correspond to the "standard performance information" as shown in
FIG. 23. The maintenance history page CP3 further includes a vacuum
performance maintenance section K14, a gas supply and discharge
performance section K15, a temperature performance section K16, and
an electrical performance section K17 of the plasma processing
chamber. These sections correspond to the "operation and
maintenance information" of the purchased apparatus.
[0625] For example, the following items are described in the
corresponding sections for the "operation and maintenance
information".
[0626] In the vacuum performance maintenance section K14:
[0627] final degree of vacuum: 1.3.times.10.sup.-5 Pa or less,
and
[0628] operational pressure: 200 Pa.
[0629] In the gas supply and discharge performance section K15:
[0630] gas flow rates:
6 SiH.sub.4 40 SCCM, NH.sub.3 160 SCCM, N.sub.2 600 SCCM, and
discharge property: 6.8 .times. 10.sup.-7 Pa .multidot.
m.sup.3/sec.
[0631] In the temperature performance section K16:
[0632] heater temperature: 302.3 .+-.4.9.degree. C., and
[0633] chamber temperature: 80.1 .+-.2.1.degree. C.
[0634] For each parameter P, the variation between the maximum
P.sub.max and the minimum P.sub.min in different plasma chambers of
a plasma processing apparatus or a plasma processing system is
defined by relationship (10B):
(P.sub.max-P.sub.min)/(P.sub.max+P.sub.min) (10B)
[0635] This variation is displayed with a standard range (a maximum
and a minimum) of each parameter of each plasma processing
apparatus or plasma processing system.
[0636] A "detail" button K18 is provided in each title column for
the corresponding sections K14, K15, K16, or K17 so that the
customer can browse the corresponding detailed information.
[0637] When the customer submits a display request, a detailed
maintenance page CP4 including detailed information on the
maintenance history is transmitted from the database D to the
customer's terminal C1.
[0638] FIG. 39 shows the "detailed maintenance information" subpage
submitted from the server S to the customer's terminal C1.
[0639] This "detailed maintenance information" subpage includes a
serial number display section K13 for displaying the serial number
of the purchased plasma processing apparatus or plasma processing
system and the plasma chambers thereof, and the selected
maintenance history columns. The selected maintenance history
columns display values of parameters P in each plasma chamber, and
variations of these parameters P at the maintenance date.
[0640] The electrical performance section K10 of the plasma
processing chamber and the electrical performance section K17 of
the plasma processing chamber include the value of the first series
resonant frequency f.sub.0, and the relationship between the value
and the power frequency f.sub.e, as described in the first to
fourth embodiments. The section K10 and the section K17 also
include the resistance R.sub.e and reactance X.sub.e of the plasma
chamber at the power frequency f.sub.e, the plasma capacitance
C.sub.0 between the plasma excitation electrode 4 and the susceptor
electrode 8, the loss capacitance C.sub.X between the plasma
excitation electrode 4, and the grounded potential portion of the
plasma chamber, etc.
[0641] The server S simultaneously acquires "standard performance
information" data such as "vacuum performance", "gas supply and
exhaust performance", "temperature performance", and "electrical
performance of plasma processing chamber", and provides the
maintenance history page CP3 and the detailed maintenance page CP4
together with the "operation and maintenance information". The
customer can thereby browse the "operation and maintenance
information" with reference to the "standard performance
information". Thus, the customer can confirm the "standard
performance information" as a reference in use, and can consult the
"operation and maintenance information" as parameters showing an
operational state, in the "performance information" of the
purchased plasma processing apparatus or plasma processing system
and the plasma chambers thereof. Also, by comparing the "standard
performance information" with the "operation and maintenance
information", the customer can check the operation of the plasma
processing apparatus or plasma processing system and the plasma
chambers thereof, can determine when maintenance is necessary, and
can determine the plasma processing state.
[0642] If the server S does not receive the log-off request from
the customer's terminal C1 after transmission of the subpages C3
and C4 to the customer's terminal C1 (Step S5), the server S
transmits an invalid connection massage to the customer's terminal
C1 (Step S8) to prompt reentry of the "customer password" or to
wait for the next display request (Step S3). If the server S
receives the log-off request from the customer's terminal C1 (Step
S5), the communication with the customer's terminal C1 is
completed.
[0643] The performance validation system according to this
embodiment includes at least one client terminal and performance
information providing means for providing performance information
to the client terminal, wherein the performance information
comprises standard operation information regarding general
information of the plasma processing apparatus and operation and
maintenance information regarding specific information of the
plasma processing apparatus, wherein the client terminal has at
least one function of requesting the display of performance
information and uploading the operation and maintenance information
to the performance information providing means. Preferably, the
standard performance information and the operation and maintenance
information comprise information regarding a first series resonant
frequency f.sub.0. Preferably, the standard performance information
is used as a catalog or a specification document. Thus, the
customer can browse the performance information including the
standard performance information and the uploaded operation and
maintenance information of the plasma processing apparatus or
system and the plasma processing chambers thereof. The customer can
obtain standard information on when the apparatus or system is
installed, and the operation and maintenance information on when
the apparatus or system and the plasma processing chambers are
used.
[0644] When the performance information includes the first series
resonant frequencies f.sub.0 and variations thereof as performance
parameters of the plasma processing chambers, the customer can
determine the performance of the plasma processing apparatus or
plasma processing system and the plasma processing chambers thereof
before deciding the to purchase the apparatus or system. Moreover,
the performance information can be output as catalogs and
specifications.
EXAMPLES
[0645] In these examples, the variation of the first series
resonant frequencies f.sub.0 of a plurality of plasma chambers was
set to be a predetermined value and changes in properties of
deposited films were measured.
[0646] The plasma processing apparatus used had two plasma
chambers, as shown in the fifth embodiment, and these plasma
chambers were of a dual-frequency excitation type.
[0647] In the plasma processing apparatus, the parallel plate
electrodes 4 and 8 were 25 cm squared, the interelectrode distance
was 15 mm, the electrical power was 800 W, and the first series
resonant frequency f.sub.0 was 40.68 MHz.
Example 5
[0648] The variation defined by the maximum frequency f.sub.0max
and the minimum frequency f.sub.0min of the first series resonant
frequencies f.sub.0 of this plasma processing apparatus was set to
be 0.09 according to relationship (10), and the average of the
first series resonant frequencies f.sub.0 was set to be 43 MHz.
Example 6
[0649] The variation defined by the maximum frequency f.sub.0max
and the minimum frequency f.sub.0min of the first series resonant
frequencies f.sub.0 of this plasma processing apparatus was set to
be 0.02 according to relationship (10), and the average of the
first series resonant frequencies f.sub.0 was set to be 43 MHz.
Comparative Example 2
[0650] The variation defined by the maximum frequency f.sub.0max
and the minimum frequency f.sub.0min of the first series resonant
frequencies f.sub.0 of this plasma processing apparatus was set to
be 0.11 according to relationship (10), and the average of the
first series resonant frequencies f.sub.0 was set to be 43 MHz.
[0651] In each of EXAMPLES 5 and 6 and COMPARATIVE EXAMPLE 2,
silicon nitride film was deposited according to the following
identical process recipe to measure the variation in the film
thicknesses:
[0652] (1) Depositing a SiN.sub.X film on a 6-inch glass substrate
by plasma enhanced CVD;
[0653] (2) Patterning a resist film by photolithography;
[0654] (3) Dry-etching the SiN.sub.X film with SF.sub.6 and
O.sub.2;
[0655] (4) Removing the resist film by O.sub.2 ashing;
[0656] (5) Measuring the roughness of the SiN.sub.X film using a
contact displacement meter;
[0657] (6) Calculating the deposition rate using the deposition
time and the film thickness; and
[0658] (7) Measuring the in-plane uniformity of the film at 16
points on the substrate.
[0659] The deposition conditions were as follows:
[0660] Substrate temperature: 350.degree. C.
[0661] SiH.sub.4 flow rate: 40 SCCM
[0662] NH.sub.3 flow rate: 200 SCCM
[0663] N.sub.2 flow rate: 600 SCCM
[0664] Deposition rate: about 200 nm/min
7 TABLE 3 Deposition Variation in In-plane Rate Deposition
Uniformity Variation (nm/min) Rate (%) (%) of f.sub.0* OMPARATIVE
Chamber 1 181 86 4.6 0.11 XAMPLE 1 Chamber 2 215 6.2 XAMPLE 5
Chamber 1 195 4.9 4.6 0.09 Chamber 2 215 5.7 XAMPLE 6 Chamber 1 207
1.9 4.6 0.02 Chamber 2 215 5.4 *f.sub.0: first series resonant
frequencies
[0665] The results shown in Table 3 demonstrate that the difference
in the film thickness between the plasma chambers is reduced when
the variation of the first series resonant frequencies f.sub.0 is
set to be in the range specified according to the present
invention. In other words, the operational characteristics of the
plasma chambers are improved by such specific variation of the
first series resonant frequencies f.sub.0.
* * * * *