U.S. patent application number 11/830309 was filed with the patent office on 2008-02-07 for plasma processing apparatus and plasma processing method.
This patent application is currently assigned to TOKYO ELECTRON LIMITED. Invention is credited to Chishio KOSHIMIZU, Naoki MATSUMOTO.
Application Number | 20080029385 11/830309 |
Document ID | / |
Family ID | 39028076 |
Filed Date | 2008-02-07 |
United States Patent
Application |
20080029385 |
Kind Code |
A1 |
KOSHIMIZU; Chishio ; et
al. |
February 7, 2008 |
PLASMA PROCESSING APPARATUS AND PLASMA PROCESSING METHOD
Abstract
A plasma processing apparatus includes a plurality of
radio-frequency power supplies for supplying radio-frequency powers
having frequencies different from each other, a common feeding line
for superposing radio-frequency powers supplied respectively from
the plurality of radio-frequency power supplies and feeding the
superposed radio-frequency power to a same radio-frequency
electrode, a radio-frequency power extracting device for extracting
radio-frequency powers having predetermined frequencies from
radio-frequency powers fed via the feeding line, and a
radio-frequency voltage detector for measuring voltages of the
radio-frequency powers having the predetermined frequencies
extracted by the radio-frequency power extracting device.
Inventors: |
KOSHIMIZU; Chishio;
(Nirasaki-shi, JP) ; MATSUMOTO; Naoki;
(Amagasaki-shi, JP) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
TOKYO ELECTRON LIMITED
Tokyo
JP
|
Family ID: |
39028076 |
Appl. No.: |
11/830309 |
Filed: |
July 30, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60849461 |
Oct 5, 2006 |
|
|
|
Current U.S.
Class: |
204/164 ;
422/186.29 |
Current CPC
Class: |
H01J 37/32165 20130101;
H01J 37/32091 20130101; H01J 37/32174 20130101; H01J 37/32706
20130101 |
Class at
Publication: |
204/164 ;
422/186.29 |
International
Class: |
B01J 19/08 20060101
B01J019/08 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 3, 2006 |
JP |
2006-211747 |
Claims
1. A plasma processing apparatus having radio-frequency electrodes
opposing each other vertically in a processing chamber, in which a
radio-frequency power is supplied to at least one of the
radio-frequency electrodes to thereby generate in the processing
chamber plasma with which a substrate is processed, the apparatus
comprising: a plurality of radio-frequency power supplies for
supplying radio-frequency powers having frequencies different from
each other; a common feeding line for feeding radio-frequency
powers supplied respectively from said plurality of radio-frequency
power supplies to a same radio-frequency electrode; a
radio-frequency power extracting device for extracting
radio-frequency powers having predetermined frequencies from
radio-frequency powers fed via said feeding line; and a
radio-frequency detector for measuring at least one or more of a
voltage, a current and a phase of the radio-frequency powers having
the predetermined frequencies extracted by said radio-frequency
power extracting device.
2. The plasma processing apparatus according to claim 1, wherein
said radio-frequency detector is a radio-frequency voltage detector
for measuring voltages of the radio-frequency powers having the
predetermined frequencies.
3. The plasma processing apparatus according to claim 1, wherein
the predetermined frequencies are frequencies of the
radio-frequency powers supplied respectively by said plurality of
radio-frequency power supplies.
4. The plasma processing apparatus according to claim 1, wherein
said radio-frequency power extracting device has at least one of a
band-pass filter, a low-pass filter and a high-pass filter which
pass only the radio-frequency powers having the predetermined
frequencies.
5. The plasma processing apparatus according to claim 1, wherein
said radio-frequency power extracting device has a radio-frequency
power decomposing device for decomposing a radio-frequency power
fed via said feeding line into the radio-frequency powers having
the predetermined frequencies.
6. The plasma processing apparatus according to claim 1, wherein
said plurality of radio-frequency power supplies have matching
devices respectively between said plurality of radio-frequency
power supplies and said feeding line.
7. The plasma processing apparatus according to claim 1, further
comprising: a direct-current voltage extracting device for
extracting a direct-current voltage from a radio-frequency power
fed via said feeding line; and a direct-current voltage detector
for measuring the direct-current voltage extracted by said
direct-current voltage extracting device.
8. The plasma processing apparatus according to claim 2, further
comprising a computer for correcting voltages of the
radio-frequency powers having the predetermined frequencies
measured by said radio-frequency voltage detector based on
impedance information which are retained in advance or obtained,
and calculating voltages of the radio-frequency powers having the
predetermined frequencies at said radio-frequency electrode.
9. A plasma processing method in which a radio-frequency power is
supplied to at least one of radio-frequency electrodes provided in
a processing chamber and opposing each other vertically, to thereby
generate in the processing chamber plasma with which a substrate is
processed, the method comprising: feeding using a common feeding
line a plurality of radio-frequency powers having frequencies
different from each other to a same radio-frequency electrode;
extracting radio-frequency powers having predetermined frequencies,
which are ones among the frequencies, from radio-frequency powers
fed via the feeding line and measuring voltages thereof; and
correcting the measured voltages using predetermined impedance
information and calculating voltages of the radio-frequency powers
having the predetermined frequencies at the same radio-frequency
electrode.
10. The plasma processing method according to claim 9, wherein when
the radio-frequency powers having the predetermined frequencies are
extracted, at least one of a band-pass filter, a low-pass filter
and a high-pass filter which pass only the radio-frequency powers
having the predetermined frequencies is used for extraction.
11. The plasma processing method according to claim 9, wherein when
the radio-frequency powers having the predetermined frequencies are
extracted, a radio-frequency power fed via the feeding line is
decomposed to the radio-frequency powers having the predetermined
frequencies and extracted.
12. The plasma processing method according to claim 9, wherein a
direct-current voltage is extracted from a radio-frequency power
fed via the feeding line and the voltage may be measured.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a plasma processing
apparatus in which plasma is generated in a processing chamber and
a substrate is processed therein, and a plasma processing
method.
[0003] 2. Description of the Related Art
[0004] In substrate processing such as etching and film formation
in manufacturing processes of a semiconductor processing device, a
liquid display device, or the like for example, processing using
plasma is widely performed.
[0005] Usually, plasma processing is performed in a plasma
processing apparatus. In this plasma processing apparatus,
electrodes opposing each other vertically are provided in a
processing chamber, in which plasma is generated by supplying a
radio-frequency power to one or both of the electrodes, and then
plasma processing of a substrate is performed.
[0006] In recent years, there has been developed a plasma
processing technique to apply a superposed radio-frequency power to
an electrode by supplying two or more radio-frequency powers having
different frequencies to one electrode. In Japanese Patent
Application No. 2001-127045, there is disclosed a plasma processing
technique using a superposed radio-frequency power by supplying two
radio-frequency powers having different frequencies to an upper
electrode, where the upper electrode and a lower electrode are
arranged to oppose each other.
[0007] In the plasma processing technique described in Japanese
Patent Application Laid-open No. 2001-127045, a first
radio-frequency power for exciting a processing gas into plasma is
supplied to the upper electrode, and a second radio-frequency power
having a frequency lower than that of the first radio-frequency
power for drawing ions in the plasma into a substrate is supplied
to the lower electrode on which the substrate is mounted. Further,
a third radio-frequency power having a frequency lower than that of
the first radio-frequency power and higher than that of the second
radio-frequency power is supplied to the upper electrode and
superposed on the first radio-frequency power. Then phases,
frequencies and outputs of the second radio-frequency power and the
third radio-frequency power are adjusted to uniformize the plasma,
and thereby processing of the substrate is performed uniformly.
SUMMARY OF THE INVENTION
[0008] However, when a substrate is processed using the plasma
processing technique described in the above-described Patent
Document 1, respective peak-to-peak voltages (Vpp) of the first
radio-frequency power and the third radio-frequency power supplied
to the upper electrode are also superposed along with superposition
of these radio-frequency powers.
[0009] When a radio-frequency power supplied to an electrode has a
single frequency, a process state of substrate processing can be
easily determined by following a behavior of a peak-to-peak voltage
(Vpp) of the radio-frequency power. For example, when an upper
electrode and a lower electrode are arranged to oppose each other,
a radio-frequency power having a single frequency for exciting a
processing gas into plasma is supplied to the upper electrode, and
a radio-frequency power having a single frequency for drawing ions
in the plasma into a substrate is supplied to the lower electrode,
it is possible to determine that the plasma generated by the upper
electrode became thin for some reason when a value of the
peak-to-peak voltage (Vpp) of the radio-frequency power supplied to
the lower electrode becomes large.
[0010] On the other hand, in the plasma processing technique
described in the above-described Patent Document 1, peak-to-peak
voltages (Vpp) of a plurality of radio-frequency powers are
superposed as described above, and a peak-to-peak voltage (Vpp) of
a radio-frequency power having a specific frequency which has
useful information is mixed with a peak-to-peak voltage (Vpp) of a
radio-frequency power having another frequency, thereby making it
difficult to be used as an index for process determination for
substrate processing.
[0011] The present invention is made in view of the above-described
problems, and an object thereof is to provide a plasma processing
apparatus and a plasma processing method capable of determining a
process state of substrate processing from a behavior of a
peak-to-peak voltage (Vpp) of a radio-frequency power having an
appropriate frequency even when two or more radio-frequency powers
having different frequencies are superposed and supplied to an
electrode arranged in a processing chamber.
[0012] To solve the above-described problems, according to the
present invention, there is provided a plasma processing apparatus
having radio-frequency electrodes opposing each other vertically in
a processing chamber, in which a radio-frequency power is supplied
to at least one of the radio-frequency electrodes to thereby
generate in the processing chamber plasma with which a substrate is
processed, the apparatus having a plurality of radio-frequency
power supplies for supplying radio-frequency powers having
frequencies different from each other, a common feeding line for
feeding radio-frequency powers supplied respectively from the
plurality of radio-frequency power supplies to a same
radio-frequency electrode, a radio-frequency power extracting
device for extracting radio-frequency powers having predetermined
frequencies from radio-frequency powers fed via the feeding line,
and a radio-frequency detector for measuring at least one or more
of a voltage, a current and a phase of the radio-frequency powers
having the predetermined frequencies extracted by the
radio-frequency power extracting device.
[0013] In the above-described plasma processing apparatus, the
radio-frequency detector may be a radio-frequency voltage detector
for measuring voltages of the radio-frequency powers having the
predetermined frequencies.
[0014] In the above-described plasma processing apparatus, the
predetermined frequencies may be frequencies of the radio-frequency
powers supplied respectively by the plurality of radio-frequency
power supplies.
[0015] In the above-described plasma processing apparatus, the
radio-frequency power extracting device may have at least one of a
band-pass filter, a low-pass filter and a high-pass filter which
pass only the radio-frequency powers having the predetermined
frequencies.
[0016] In the above-described plasma processing apparatus, the
radio-frequency power extracting device may have a radio-frequency
power decomposing device for decomposing a radio-frequency power
fed via the feeding line into the radio-frequency powers having the
predetermined frequencies.
[0017] In the above-described plasma processing apparatus, the
plurality of radio-frequency power supplies may have matching
devices respectively between the plurality of radio-frequency power
supplies and the feeding line.
[0018] The above-described plasma processing apparatus may further
include a direct-current voltage extracting device for extracting a
direct-current voltage from a radio-frequency power fed via the
feeding line, and a direct-current voltage detector for measuring
the direct-current voltage extracted by the direct-current voltage
extracting device.
[0019] The above-described plasma processing apparatus may further
include a computer for correcting voltages of the radio-frequency
powers having the predetermined frequencies measured by the
radio-frequency voltage detector based on impedance information
which are retained in advance or obtained, and calculating voltages
of the radio-frequency powers having the predetermined frequencies
at the radio-frequency electrode.
[0020] Further, according to the present invention, there is
provided a plasma processing method in which a radio-frequency
power is supplied to at least one of radio-frequency electrodes
provided in a processing chamber and opposing each other
vertically, to thereby generate in the processing chamber plasma
with which a substrate is processed, the method including feeding
using a common feeding line a plurality of radio-frequency powers
having frequencies different from each other to a same
radio-frequency electrode, extracting radio-frequency powers having
predetermined frequencies, which are ones among the frequencies,
from radio-frequency powers fed via the feeding line and measuring
voltages thereof, and correcting the measured voltages using
predetermined impedance information and calculating voltages of the
radio-frequency powers having the predetermined frequencies at the
same radio-frequency electrode.
[0021] In the above-described plasma processing method, when the
radio-frequency powers having the predetermined frequencies are
extracted, at least one of a band-pass filter, a low-pass filter
and a high-pass filter which pass only the radio-frequency powers
having the predetermined frequencies may be used for
extraction.
[0022] In the above-described plasma processing method, when the
radio-frequency powers having the predetermined frequencies are
extracted, a radio-frequency power fed via the feeding line may be
decomposed to the radio-frequency powers having the predetermined
frequencies and extracted.
[0023] In the above-described plasma processing method, a
direct-current voltage may be extracted from a radio-frequency
power fed via the feeding line and the voltage may be measured.
[0024] According to the present invention, it is possible to use a
peak-to-peak voltage (Vpp) of a radio-frequency power having an
appropriate frequency as an index to determine a process state of
substrate processing from a behavior of the peak-to-peak voltage
even when two or more radio-frequency powers having different
frequencies are superposed and supplied to an electrode arranged in
a processing chamber, and thus operation of the plasma processing
apparatus can be stabilized.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] FIG. 1 is a structure diagram of a plasma etching apparatus
1 as a plasma processing apparatus according to a first embodiment
of the present invention:
[0026] FIG. 2 is a structure diagram of a plasma etching apparatus
1 as a plasma processing apparatus according to a second embodiment
of the present invention; and
[0027] FIG. 3 is a structure diagram of a plasma etching apparatus
1 as a plasma processing apparatus according to a third embodiment
of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0028] Hereinafter, preferred embodiments of the present invention
will be described with reference to the drawings. Note that in this
specification and drawings, elements having substantially the same
functions and structures are designated the same reference
numerals, and thereby duplicating explanations are omitted.
[0029] FIG. 1 is a structure diagram of a plasma etching apparatus
1 as a plasma processing apparatus according to an embodiment of
the present invention. As shown in FIG. 1, the plasma etching
apparatus 1 has a processing chamber 2 in a substantially
cylindrical shape for example. Inside the processing chamber 2, a
processing space K is formed. Wall portions A2 of the processing
chamber 2 are grounded for protection. In the processing chamber 2,
an upper electrode 5 and a lower electrode 6 as radio-frequency
electrodes are arranged to oppose each other. The upper electrode 5
and the lower electrode 6 are both in a substantially disc shape
and formed of a conductive material. Between the upper electrode 5
and the wall portions A2, an insulator A1 is interposed. The lower
electrode 6 combines the role of a mounting table for a substrate
W. In the processing space K, a processing gas is supplied via a
gas supply path 10 and the upper electrode 5 which also has a
function as a shower head. Further, the processing gas in the
processing space K is exhausted via a gas exhaust path 11.
[0030] To the upper electrode 5, a radio-frequency power supply 16
is connected electrically via a matching device 15. The
radio-frequency power supply 16 can supply a radio-frequency power
having a frequency of 60 MHz for example to the upper electrode 5.
The matching device 15 can control an impedance related to a
fundamental wave, a harmonic or the like of a radio-frequency power
for example.
[0031] To the lower electrode 6, a radio-frequency power supply 21
for supplying a radio-frequency power having a frequency of 2 MHz
for example via a matching device 20 is connected electrically.
Further, to a feeding point 25 located between the lower electrode
6 and the matching device 20, a radio-frequency power supply 31 for
supplying a radio-frequency power having a frequency of 13 MHz for
example via a matching device 30 is connected electrically.
Accordingly, the radio-frequency power supplied from the
radio-frequency power supply 21 and the radio-frequency power
supplied from the radio-frequency power supply 31 are superposed
with each other on a common feeding line 35 from the feeding point
25 to the lower electrode 6, and the superposed radio-frequency
power is fed to the lower electrode 6. The matching devices 20, 30
can control an impedance with respect to a fundamental wave, a
harmonic, or the like of a radio-frequency power for example.
[0032] To a measurement point 40 on the feeding line 35, a
radio-frequency voltage detector 42 as a radio-frequency detector
is connected via a low-pass filter 41 as a radio-frequency power
extracting device which passes only a radio-frequency power having
a frequency lower than a predetermined threshold frequency. Also,
to the measurement point 40, a radio-frequency voltage detector 46
is connected via a high-pass filter 45 as a radio-frequency power
extracting device which passes only a radio-frequency power having
a frequency higher than a predetermined threshold frequency. The
radio-frequency voltage detectors 42, 46 are connected to the
measurement point 40 in parallel with each other. To the
radio-frequency voltage detectors 42, 46, a computer 50, which will
be described later, for analyzing voltages measured by the
radio-frequency voltage detectors 42, 46 is connected.
[0033] The threshold frequencies of the low-pass filter 41 and the
high-pass filter 45 are both set to a value larger than the
frequency of 2 MHz of the radio-frequency power supplied by the
radio-frequency power supply 21 and lower than the frequency of 13
MHz of the radio-frequency power supplied by the radio-frequency
power supply 31. Thus, using the low-pass filter 41, a
radio-frequency power having a frequency of 2 MHz which is the same
as the radio-frequency power supplied by the radio-frequency power
supply 21 can be extracted from the superposed radio-frequency
power, and a voltage thereof can be measured by the radio-frequency
voltage detector 42. Also, using the high-pass filter 45, a
radio-frequency power having a frequency of 13 MHz which is the
same as the radio-frequency power supplied by the radio-frequency
power supply 31 can be extracted from the superposed
radio-frequency power, and a voltage thereof can be measured by the
radio-frequency voltage detector 46.
[0034] The computer 50 is connector to the matching devices 20, 30.
Thus the computer 50 can obtain values of variable capacitors in
the matching devices 20, 30 as impedance information. Also, the
computer 50 retains in advance impedance information related to a
first radio-frequency system 55 constituted of the radio-frequency
power supply 21, the lower electrode 6, and so on and impedance
information related to a second radio-frequency system 56
constituted of the radio-frequency power supply 31, the lower
electrode 6, and so on. These impedance information include an
impedance value of the lower electrode 6, and so on. The computer
50 can calculate an impedance value of the first radio-frequency
system 55 and an impedance value of the second radio-frequency
system 56 respectively based on the impedance information which is
retained in advance or obtained as described above.
[0035] Further, the computer 50 can correct the voltage measured by
the radio-frequency voltage detector 42 based on the calculated
impedance value of the first radio-frequency system 55, and
calculate the voltage of the radio-frequency power having a
frequency of 2 MHz in the lower electrode 6. Similarly, the
computer 50 can correct the voltage measured by the radio-frequency
voltage detector 46 based on the calculated impedance value of the
second radio-frequency system 56, and calculate the voltage of the
radio-frequency power having a frequency of 13 MHz in the lower
electrode 6. To the computer 50, there are connected a display 60
displaying values of the radio-frequency powers having frequencies
of 2 MHz, 13 MHz in the lower electrode 6 calculated in this
manner, a recording device 61 for recording the values and a higher
system 62 for performing analysis and the like.
[0036] Next, using the plasma etching apparatus 1 constructed as
above, a plasma etching method for a substrate W as an example of a
plasma processing method according to an embodiment of the present
invention will be explained.
[0037] First, the substrate W is carried into the processing
chamber 2 and mounted on the lower electrode 6. Exhaustion is
performed through the exhaust path 11, the inside of the processing
chamber 2 is decompressed, and a predetermined processing gas is
supplied to the processing chamber 2 via the upper electrode 5 from
the gas supply path 10.
[0038] Next, the radio-frequency power supply 16 supplies to the
upper electrode 5 a radio-frequency power having a frequency of 60
MHz for generating plasma. Thus the processing gas in the
processing space K is excited into plasma. Next, the
radio-frequency power supply 21 of the first radio-frequency system
55 supplies to the lower electrode 6 a radio-frequency power having
a frequency of 2 MHz and ions in the generated plasma are drawn
into the substrate W, and thereby a surface film of the substrate W
is etched. Further, the radio-frequency power supply 31 of the
second radio-frequency system 56 supplies to the lower electrode 6
a radio-frequency power having a frequency of 13 MHz, and as a
result, a superposed radio-frequency power in which the
radio-frequency power having a frequency of 2 MHz and the
radio-frequency power having a frequency of 13 MHz are superposed
is supplied to the lower electrode 6 via the feeding line 35. Note
that there is an advantage that spreading of energy of the ions
entering the substrate W is aligned by supplying the
radio-frequency power having a frequency of 13 MHz by the
radio-frequency power supply 31 of the second radio-frequency
system 56.
[0039] When the surface film of the substrate W is etched as
described above, a voltage of the superposed radio-frequency power
supplied to the lower electrode 6 is measured by the
radio-frequency voltage detector 42 connected via the low-pass
filter 41 and the radio-frequency voltage detector 46 connected via
the high-pass filter 45, respectively. From the superposed
radio-frequency power passed through the low-pass filter 41, only
the radio-frequency power having a frequency of 2 MHz is extracted,
and a voltage V.sub.1 thereof is measured. From the superposed
radio-frequency power passed through the high-pass filter 45, only
the radio-frequency power having a frequency of 13 MHz is
extracted, and a voltage V.sub.2 thereof is measured.
[0040] The measured voltages V.sub.1, V.sub.2 are inputted to the
computer 50. In the computer 50, respective values of the variable
capacitors in the connected matching devices 20, 30 are obtained,
and based on impedance information and so on of the lower electrode
6 retained in advance, impedances of the first radio-frequency
system 55 and the second radio-frequency system 56 are calculated
in advance. Then, in the computer 50, the measured values of the
voltages V.sub.1, V.sub.2 are corrected respectively based on the
calculated impedances of the first radio-frequency system 55 and
the second radio-frequency system 56, and the voltages V.sub.10,
V.sub.20 of the radio-frequency powers having frequencies of 2 MHz,
13 MHz in the lower electrode 6 are calculated respectively. The
calculated voltages V.sub.10, V.sub.20 are inputted to the display
60 and displayed thereon so that an operator can monitor behaviors
of them. Thus, the operator can comprehend the progress of the
process of the substrate W from the behaviors (for example
respective peak-to-peak voltages Vpp or the like) of the voltages
V.sub.10, V.sub.20 displayed for example, and detect abnormality of
the process immediately.
[0041] Also, the calculated voltages V.sub.10, V.sub.20 are
inputted to the recording device 61 and recorded therein. Further,
the calculated voltages V.sub.10, V.sub.20 are inputted to the
higher system 62, and in this higher system 62, respective
peak-to-peak voltages Vpp are calculated. Based on changes in the
calculated peak-to-peak voltages Vpp, analysis of a process state
is performed such as whether the plasma etching processing of the
substrate W is in a normal state or not.
[0042] According to the above embodiment, when the superposed
radio-frequency power in which the two radio-frequency powers
having different frequencies of 2 MHz, 13 MHz are superposed is
supplied to the lower electrode 6, the radio-frequency powers
having respective frequencies of 2 MHz, 13 MHz are extracted by
passing through the low-pass filter 41 and the high-pass filter 45,
and then the voltages of the respective extracted radio-frequency
powers are measured. Thus, behaviors of the peak-to-peak voltages
Vpp of the respective radio-frequency powers can be comprehended,
and the process state of the substrate processing can be determined
properly. Particularly, with the computer 50 arranged to calculate
impedances of the respective radio-frequency systems 55, 56, make
correction based on these impedances, and calculate voltages of the
respective radio-frequency powers in the lower electrode 6, the
process of the plasma processing apparatus can be comprehended more
accurately. Therefore, operation of the plasma processing apparatus
can be stabilized.
[0043] As a second embodiment of the present invention, as shown in
FIG. 2, to the measurement point 40 on the feeding line 35, a
direct-current voltage detector 66 may be connected via a low-pass
filter 65 as a direct-current voltage extracting device which
eliminates radio-frequency components and passes only a
direct-current voltage in parallel to the radio-frequency voltage
detectors 42, 46. Further, the direct-current voltage detector 66
is connected to the computer 50.
[0044] According to the second embodiment as above, a
direct-current voltage can be extracted using the low-pass filter
65 from the superposed radio-frequency power supplied to the lower
electrode 6 by the radio-frequency power supplies 21, 31, and a
direct-current bias voltage Vdc in the lower electrode 6 can be
measured. A behavior of this direct-current bias voltage Vdc can be
followed. For example, after a measured value of the direct-current
bias voltage Vdc is inputted to the computer 50 and necessary
processing is performed thereon, the value can be inputted to the
display 60 and displayed thereon, inputted to the recording device
61 and recorded therein, or inputted to the higher system 62 and
analyzed. Thus, the process of the plasma processing apparatus can
be comprehended more accurately, and operation of the plasma
processing apparatus can be stabilized further. Note that also in
the second embodiment, the effect obtained in the first embodiment,
which is explained using FIG. 1, can be obtained similarly.
[0045] As a third embodiment of the present invention, as shown in
FIG. 3, instead of the low-pass filter 41 and the high-pass filter
45 shown in FIG. 1, a radio-frequency power decomposing device 70
may be connected to the measurement point 40 on the feeding line 35
as a radio-frequency power extracting device. The radio-frequency
power decomposing device 70 can decompose the superposed
radio-frequency power to obtain values of respective components of
the radio-frequency powers having frequencies of 2 MHz, 13 MHz.
After obtaining respective voltages from the respective decomposed
radio-frequency powers, the radio-frequency power decomposing
device 70 is configured to input the voltages to each of the
connected display 60, the recording device 61 and the higher system
62 which are connected. Thus, displaying on the display 60,
recording in the recording device 61, or analyzing in the higher
system 62 can be performed. In this embodiment, peak-to-peak
voltages and so on of the respective radio-frequency powers are
obtained by the radio-frequency power decomposing device 70. Note
that the higher system 62 may be arranged to obtain the
peak-to-peak voltages and so on of the obtained respective
radio-frequency powers.
[0046] According to the third embodiment of the present invention,
the superposed radio-frequency power in which radio-frequency
powers supplied by the radio-frequency power supplies 21, 31 are
superposed can be decomposed by the radio-frequency power
decomposing device 70, and in the radio-frequency power decomposing
device 70 subsequently, the peak-to-peak voltages and so on can be
obtained from the voltages of the respective radio-frequency
powers. Thus, the structure of the apparatus can be simplified.
Note that also in the third embodiment, the effect obtained in the
first embodiment, which is explained with FIG. 1, can be obtained
similarly.
[0047] As above, the preferred embodiments of the present invention
have been explained with reference to the attached drawings, but
the present invention is not limited to such examples. It is clear
that a person skilled in the art can devise various variation
examples and modification examples within the scope of technical
ideas described in the claims, and it is understood that such
changes and modifications also belong to the technical scope of the
present invention as a matter of course.
[0048] In the above-described embodiments, there is explained the
case where the single low-pass filter 41 and the single high-pass
filter 45 are used as the radio-frequency power extracting device,
but a plurality of low-pass filters and a plurality of high-pass
filters may be used as the radio-frequency power extracting device.
Also, these filters may be combined, or another filter such as a
band-pass filter may be used.
[0049] In the above-described embodiments, there is explained the
case where the radio-frequency electrode to which the superposed
radio-frequency power in which a plurality of radio-frequency
powers are superposed is supplied is the lower electrode 6, but the
radio-frequency electrode to which the superposed radio-frequency
power is supplied may be the upper electrode 5, or may be both the
upper electrode 5 and the lower electrode 6. Also, the apparatus
may be constructed such that a radio-frequency power for generating
plasma and a radio-frequency power for drawing ions are superposed
for the lower electrode 6, and a radio-frequency power is not
applied to the upper electrode 5.
[0050] In the above-described embodiments, there is explained the
case where two radio-frequency powers having different frequencies
are supplied to the lower electrode 6 as a radio-frequency
electrode, but there may be three or more radio-frequency powers
supplied to the radio-frequency electrode.
[0051] In the above-described embodiments, there is explained the
case where the frequency of the radio-frequency power supplied to
the upper electrode 5 is 60 MHz, and the frequencies of the
radio-frequency powers supplied to the lower electrode 6 are 2 MHz
and 13 MHz, but the frequency of a radio-frequency power supplied
to each radio-frequency electrode may be any frequency.
[0052] In the above-described embodiments, there is explained the
case where devices connected to the computer 50 or the
radio-frequency power decomposing device 70 so as to process values
of voltages of respective radio-frequency powers having respective
frequencies or direct-current voltages obtained from the superposed
radio-frequency power are the display 60, the recording device 61
and the higher system 62, but devices for processing values of
voltages of respective radio-frequency powers or direct-current
voltages may be only a part of these devices or may be another
device.
[0053] In the above-described embodiments, there is explained the
case where the radio-frequency voltage detector with an
intervention of the radio-frequency power extracting device is used
as a radio-frequency detector to detect a radio-frequency voltage,
but there may be adopted a form in which a detector for detecting
respective radio-frequency current and/or phase is used as a
radio-frequency detector to finally comprehend plasma in a plasma
processing apparatus.
[0054] In the above-described embodiments, there is explained the
case where the superposed radio-frequency power is actually
decomposed using the radio-frequency power decomposing device 70 to
obtain respective radio-frequency powers, but the respective
radio-frequency powers may be obtained by analysis without actually
decomposing the superposed radio-frequency power in the
radio-frequency power decomposing device 70.
[0055] The present invention is useful for plasma processing
equipment for a substrate for example, and particularly useful for
plasma etching equipment for plasma etching a substrate.
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