U.S. patent application number 10/344042 was filed with the patent office on 2004-04-08 for processing apparatus and cleaning method.
Invention is credited to Ishizuka, Shuuichi, Nakase, Risa, Oka, Shinsuke, Yokoyama, Osamu.
Application Number | 20040065344 10/344042 |
Document ID | / |
Family ID | 18730966 |
Filed Date | 2004-04-08 |
United States Patent
Application |
20040065344 |
Kind Code |
A1 |
Oka, Shinsuke ; et
al. |
April 8, 2004 |
Processing apparatus and cleaning method
Abstract
Provided is a parallel-plate-type processing apparatus (10),
which performs plasma CVD and includes a chamber (11) to be
cleaned. To perform cleaning of the chamber (11), plasma of a gas
including fluorine is generated outside the chamber (11), and
supplied into the chamber (11). During the cleaning, an RF power is
applied to electrode plates (12, 17) inside the chamber (11).
Inventors: |
Oka, Shinsuke; (Kanagawa,
JP) ; Yokoyama, Osamu; (Kanagawa, JP) ;
Nakase, Risa; (Kanagawa, JP) ; Ishizuka,
Shuuichi; (Yamanashi, JP) |
Correspondence
Address: |
Crowell & Moring
PO Box 14300
Washington
DC
20044-4300
US
|
Family ID: |
18730966 |
Appl. No.: |
10/344042 |
Filed: |
November 7, 2003 |
PCT Filed: |
August 7, 2001 |
PCT NO: |
PCT/JP01/06784 |
Current U.S.
Class: |
134/1.1 ; 134/19;
134/22.1; 134/31; 156/345.29; 156/345.35; 156/345.37; 156/345.47;
438/905 |
Current CPC
Class: |
B08B 7/0035 20130101;
C23C 16/4411 20130101; H01J 37/32862 20130101; H01J 37/3244
20130101; C23C 16/4405 20130101 |
Class at
Publication: |
134/001.1 ;
134/019; 134/022.1; 134/031; 156/345.29; 156/345.35; 156/345.37;
156/345.47; 438/905 |
International
Class: |
C25F 005/00 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 8, 2000 |
JP |
2000-239426 |
Claims
1. A processing apparatus (10) comprising: a chamber (11); a gas
source (SA) for supplying a gas for cleaning inside of said chamber
(11); a gas line (L1) for introducing the gas supplied from said
gas source (SA) into said chamber (11); an activator (12) which is
prepared in said gas line (L1) and activates the gas supplied from
said gas source (SA); and at least three gas inlets (28) which are
provided at a side wall of said chamber (11) and connected to said
gas line (L1).
2. The processing apparatus (10) according to claim 1, wherein said
at least three gas inlets (28) are provided at equal intervals.
3. The processing apparatus (10) according to claim 1, wherein said
processing apparatus (10) includes a plasma generation mechanism
for providing a target object with plasma processing in said
chamber (11).
4. The processing apparatus (10) according to claim 1, wherein said
activator (12) generates plasma of the gas.
5. A processing apparatus (10) comprising: a chamber (11); a gas
source (SA) for supplying a gas for cleaning inside of said chamber
(11); a gas line (L1) for introducing the gas supplied from said
gas source (SA) into said chamber (11); an activator (12) which is
prepared in said gas line (L1) and activates the gas supplied from
said gas source (SA); and a gas inlet (28) which is provided on a
surface of said chamber (11) and connected to said gas line (L1),
and wherein said gas inlet (28) is covered with a lid member (29)
including at least one opening (30) having an area in a range
between 50% and 80% of an area of a main surface of the lid member
(29).
6. The processing apparatus (10) according to claim 5, wherein said
processing apparatus (10) includes a plasma generation mechanism
for providing a target object with plasma processing in said
chamber (11).
7. The processing apparatus (10) according to claim 5, wherein said
activator (12) generates plasma of the gas.
8. A processing apparatus (10) comprising: a chamber (11); a gas
source (SA) for supplying a gas for cleaning inside of said chamber
(11); a gas line (L1) for introducing the gas supplied from said
gas source (SA) into said chamber (11); an activator (12) which is
prepared in said gas line (L1) and activates the gas supplied from
said gas source (SA); and a gas inlet (28) which is provided on a
surface of said chamber (11) and connected to said gas line (L1),
wherein said gas inlet (28) is covered with a lid member (29)
including at least one opening (30) which is provided diagonally
with respect to a thickness direction of the lid member (29).
9. The processing apparatus (10) according to claim 8, wherein said
processing apparatus (10) includes a plasma generation mechanism
for providing a target object with plasma processing in said
chamber (11).
10. The processing apparatus (10) according to claim 8, wherein
said activator (12) generates plasma of the gas.
11. A processing apparatus (10) comprising: a chamber (11); a gas
source (SA) for supplying a gas for cleaning inside of said chamber
(11); a gas line (L1) for introducing the gas supplied from said
gas source (SA) into said chamber (11); an activator (12) which is
prepared in said gas line (L1) and activates the gas supplied from
said gas source (SA); and a heat mechanism for heating the internal
surface of said chamber (11).
12. The processing apparatus (10) according to claim 11, wherein
said heat mechanism includes a path (31) for chiller embedded in
said chamber (11).
13. The processing apparatus (10) according to claim 11, wherein
said heat mechanism includes a heater (32) which is embedded in
said chamber (11).
14. The processing apparatus (10) according to claim 11, wherein:
said chamber (11) includes a window (34); and said heat mechanism
is provided outside said chamber (11) and includes a lamp (33) for
irradiating light to the internal surface of the chamber (11)
through the window (34).
15. The processing apparatus (10) according to claim 11, wherein
said processing apparatus (10) includes a plasma generation
mechanism for providing a target object with plasma processing in
said chamber (11).
16. The processing apparatus (10) according to claim 11, wherein
said activator (12) generates plasma of the gas.
17. A method for cleaning a processing apparatus (10) including two
electrodes in a chamber (11), said method comprising the steps of:
introducing a gas for cleaning into said chamber (11); and applying
an RF power to each of the two electrodes (12, 17), thereby
activating the gas for cleaning.
18. The method according to claim 17, wherein the gas for cleaning
is activated to generate plasma thereof.
19. A method for cleaning a processing apparatus (10) including two
electrodes (12, 17) in a chamber (11), said method comprising the
steps of: activating a gas for cleaning outside said chamber (11);
introducing the activated gas into said chamber (11); and applying
an RF power to at least one of the two electrodes (12, 17), thereby
activating the gas for cleaning.
20. The method according to claim 19, wherein the gas for cleaning
is activated to generate plasma thereof.
21. A method for cleaning a processing apparatus (10) including a
chamber (11), said method comprising the steps of: activating a gas
for cleaning outside said chamber (11); and introducing the
activated gas into the chamber (11) in at least three ways.
22. The method according to claim 21, wherein said processing
apparatus (10) provides a target object with plasma processing in
the chamber (11).
23. The method according to claim 21, wherein the gas for cleaning
is activated to generate plasma thereof.
24. A method for cleaning a processing apparatus (10) including a
chamber (11), said method comprising the steps of: activating a gas
outside the chamber (11); and introducing the activated gas into
the chamber (11) in various directions.
25. The method according to claim 24, wherein said processing
apparatus (10) provides a target object with plasma processing in
the chamber (11).
26. The method according to claim 24, wherein the gas for cleaning
is activated to generate plasma thereof.
27. A method for cleaning a processing apparatus (10) including a
chamber (11), said method comprising the steps of: activating a gas
for cleaning outside the chamber (11); introducing the gas into the
chamber (11); and retaining pressure in the chamber (11) in a range
between 100 Pa and 400 Pa.
28. The method according to claim 27, wherein said processing
apparatus (10) provides a target object with plasma processing in
the chamber (11).
29. The method according to claim 27, wherein the gas for cleaning
is activated to generate plasma thereof.
30. A method for cleaning a processing apparatus (10) including a
chamber (11), said method comprising the steps of: activating a gas
for cleaning outside the chamber (11); introducing the gas into the
chamber (11); and heating an inner surface of the chamber (11).
31. The method according to claim 30, wherein said processing
apparatus (10) provides a target object with plasma processing in
the chamber (11).
32. The method according to claim 30, wherein the gas for cleaning
is activated to generate plasma thereof.
Description
TECHNICAL FIELD
[0001] The present invention relates to a processing apparatus and
a cleaning method in which an efficient cleaning is possible.
BACKGROUND ART
[0002] Various CVD (Chemical Vapor Deposition) apparatuses are used
for manufacturing electronic devices, such as semiconductor
devices, LCD (Liquid Crystal Display) devices, etc. Plasma CVD
apparatuses are widely used for forming high quality films.
[0003] The plasma CVD apparatus forms a film on a semiconductor
wafer contained inside a decompressed chamber, using a CVD method.
The CVD method employs a gas phase reaction. Thus, films are formed
only on the surface of the wafers, but on the surface (internal
wall, etc.) of a chamber member. Thus formed films cause particles
to be generated, thereby lowering the yield of the products. In
such circumstances, it is necessary to regularly clean the inside
of the chamber, to remove the films formed on the chamber
member.
[0004] A well-known method for cleaning the inside of the chamber
is an in-situ plasma cleaning method, wherein a cleaning gas is
introduced into the chamber, and plasma is generated from a gas
inside the chamber. However, plasma is generated inside the
chamber, so that the chamber member is likely to be
deteriorated.
[0005] A remote plasma cleaning method has been proposed. In this
remote plasma cleaning method, plasma of a cleaning gas is
generated outside the chamber, and the generated plasma is
introduced into the chamber so as to clean the inside of the
chamber. Using this remote plasma cleaning method, the chamber
member is unlikely to be deteriorated. Such a remote plasma
cleaning method is disclosed in Unexamined Japanese Patent
Application KOKAI Publication No. H9-69504 (U.S. Priority No.
08/278605).
[0006] A problem in the remote plasma cleaning method is that it
requires a relatively long period of time for the cleaning. In the
remote plasma cleaning method, the plasma gas is introduced from
one or two point(s) into the chamber, so that the inside of the
chamber is not evenly cleaned. Using the remote plasma cleaning
method, it takes a long time for cleaning entirely the inside of
the chamber, resulting that a part of the chamber member is
deteriorated due to the excessive cleaning.
[0007] Accordingly, in the conventional CVD apparatus, the cleaning
of the chamber is not performed with high efficiency, and a high
yield of the products is not sufficiently be obtained.
DISCLOSURE OF INVENTION
[0008] The present invention has been made in consideration of the
above. It is accordingly an object of the present invention to
provide a processing apparatus and a cleaning method by which a
cleaning with high efficiency is possible.
[0009] In order to achieve the above objects, according to the
first aspect of the present invention, there is provided a
processing apparatus (10) comprising: a chamber (11); a gas source
(SA) for supplying a gas for cleaning inside of said chamber (11);
a gas line (L1) for introducing the gas supplied from said gas
source (SA) into said chamber (11); an activator (27) which is
prepared in said gas line (L1) and activates the gas supplied from
said gas source (SA); and at least three gas inlets (28) which are
provided at a side wall of said chamber (11) and connected to said
gas line (L1).
[0010] In order to achieve the above objects, according to the
second aspect of the present invention, there is provided a method
for cleaning a processing apparatus (10) including two electrodes
(12, 17) in a chamber (11), said method comprising the steps of:
introducing a gas for cleaning into said chamber (11); and applying
an RF power to each of the two electrodes (12, 17), thereby
activating the gas for cleaning.
BRIEF DESCRIPTION OF DRAWINGS
[0011] FIG. 1 is a diagram showing the structure of a processing
apparatus according to the first embodiment of the present
invention.
[0012] FIG. 2 is a diagram showing cleaning results obtained using
the processing apparatus of FIG. 1.
[0013] FIG. 3 is a diagram showing cleaning results obtained using
the processing apparatus of FIG. 1.
[0014] FIG. 4 is a diagram showing the structure of a processing
apparatus according to the second embodiment of the present
invention.
[0015] FIG. 5 is a cross sectional view showing the processing
apparatus of FIG. 4.
[0016] FIG. 6 is a diagram showing cleaning results obtained using
the processing apparatus of FIG. 4.
[0017] FIG. 7 is a diagram showing cleaning results obtained using
the processing apparatus of FIG. 4.
[0018] FIG. 8 is a diagram showing the structure of a processing
apparatus according to the third embodiment of the present
invention.
[0019] FIG. 9 is a diagram showing cleaning results obtained using
the processing apparatus of FIG. 8.
[0020] FIG. 10 is a diagram showing a processing apparatus as a
comparative example.
[0021] FIG. 11 is a diagram showing a lid member included in a
processing apparatus according to the fourth embodiment.
[0022] FIG. 12 is a diagram showing cleaning results obtained using
the processing apparatus according to the fourth embodiment.
[0023] FIG. 13 is a diagram showing a modification of the lid
member included in the processing apparatus according to the fourth
embodiment.
[0024] FIG. 14 is a diagram showing further cleaning results
obtained using the processing apparatus of the fourth
embodiment.
[0025] FIG. 15 is a diagram showing the lid member as a comparative
example as a comparative example.
[0026] FIG. 16 is a diagram showing the structure of a processing
apparatus according to the fifth embodiment.
[0027] FIG. 17 is a diagram showing cleaning results obtained using
the processing apparatus of the fifth embodiment.
[0028] FIG. 18 is a diagram showing another structure of the
processing apparatus of the fifth embodiment.
[0029] FIG. 19 is a diagram showing another structure of the
processing apparatus of the fifth embodiment.
BEST MODE FOR CARRYING OUT THE INVENTION
[0030] A processing apparatus according to the first embodiment of
the present invention will now be explained with reference to the
accompany drawings.
[0031] The processing apparatus according to the first embodiment
includes a chamber. In this chamber, SiOF films are formed
respectively on semiconductor wafers (hereinafter referred to as a
wafer W) using a plasma CVD method, with a process gas containing
SiH.sub.4, SiF.sub.4 and O.sub.2. The SiOF film remaining in the
chamber after the formation is removed therefrom, using a cleaning
gas containing NF.sub.3.
First Embodiment
[0032] FIG. 1 shows a cross sectional view of a processing
apparatus 10 according to the first embodiment of the present
invention. As shown in FIG. 1, the processing apparatus 10
comprises a chamber 1, a cleaning gas line L1, a process gas line
L2, an exhaust line L3, and a system controller 100.
[0033] The cleaning gas line L1 connects the chamber 11 to an
NF.sub.3 source SA, serving as a cleaning gas source, and also to
an Ar source SB, serving as a carrier gas source. The NF.sub.3
source SA and Ar source SB are connected to the cleaning gas line
L1, respectively through mass-flow controllers MA and MB, and also
through valves VA and VB. Those lines, for connecting the NF.sub.3
source SA and Ar source SB, and chamber 11 are, connected on vent
parts of the valves VA and VB so as to be formed into a single
line. In this structure, NF.sub.3 and Ar are mixed at a
predetermined ratio by the controllers MA and MB and valves VA and
VB, and supplied to the chamber 1.
[0034] The process gas line L2 connects chamber 11 to an SiF.sub.4
source SC, an SiH.sub.4 source SD, an O.sub.2 source SE, and to an
Ar source SF. The SiF.sub.4 source SC, SiH.sub.4 source SD, O.sub.2
source SE, and Ar source SF are connected to the process gas line
L2 respectively through mass-flow controllers MC, MD, ME, and MF,
and also through valves VC, VD, VE, and VF. Those lines for
connecting the SiF.sub.4 source SC, SiH.sub.4 source SD, O.sub.2
source SE and Ar source SF, and chamber 11 are converged on the
vent parts of the valves VC, VD, VE, and VF, so as to be formed
into a single line. In this structure, SiF.sub.4, SiH.sub.4,
O.sub.2 and Ar are mixed at a predetermined ratio by the mass-flow
controllers MC, MD, ME, and MF and also the valves VD, VD, VE, and
VF, and supplied to the chamber 11.
[0035] The chamber 11 is a reactive chamber which can be
decompressed into a vacuum state. The chamber 11 is formed
approximately in a cylindrical shape, made of aluminum, etc., and
is grounded.
[0036] Provided on the side wall of the chamber 11 is a gate for
carrying in and out wafers W to and from the chamber 11 through a
gate valve. A susceptor 12 is provided in the middle of the chamber
11.
[0037] The susceptor 12 made from a conductor such as aluminum, for
example, and formed almost in a cylindrical shape. Mounted on the
upper surface of the susceptor 12 is a wafer W and an electrostatic
chuck which electrostatically absorbs the wafer W so as to fix the
wafer W thereonto.
[0038] A focus ring 13 is provided on the upper surface of the
susceptor 12. In this structure, plasma can effectively contact the
wafer W mounted on the susceptor 12. There is provided in the
susceptor 12 a lift pin which can go up and down for receiving and
providing the wafer.
[0039] A chiller room 14 is provided in the susceptor 12. A chiller
flows into each of the chiller room 14 through a pipe. The
temperature of the susceptor 12 and wafer W on the susceptor 12 is
adjusted by the chiller. Note that, a chiller means a temperature
controlling medium herein.
[0040] The susceptor 12 is connected to the first RF power source
16 through the first matching box 15. One end of the first RF power
source 16 is grounded; so that an RF voltage can be applied to the
susceptor 12.
[0041] An electrode plate 17 is tightened up to an electrode
supporter 18 at the ceiling of the chamber 11. The electrode plate
17 faces and is parallel to the susceptor 12. The electrode plate
17 is formed from a conductor such as aluminum. A Shield ring 19,
for protecting the sections of the electrode plate 17 which are
fixed to the electrode supporter 18, is provided beneath the
peripheral of the electrode plate 17.
[0042] The electrode plate 17 is connected to the second RF power
source 21 through the second matching box 20. One end of the second
RF power source 21 is grounded, so that an RF voltage is applied to
the electrode plate 17. Accordingly, the electrode plate 17 and
susceptor 12 function respectively as an upper electrode and lower
electrode of a parallel-plate-type plasma CVD apparatus.
[0043] A cleaning-gas inlet pipe 22 and a process-gas inlet pipe 23
are provided on the upper section of the chamber 11. The
cleaning-gas inlet pipe 22 is connected to the cleaning gas line
L1, so that a cleaning gas is introduced into the chamber 11
through the cleaning gas inlet pipe 22. The process-gas inlet pipe
23 is connected to the process gas line L2, so that a process gas
is introduced into the chamber 11 through the process-gas inlet
pipe 23.
[0044] The electrode supporter 18 includes a diffusing portion such
as a hollow, for diffusing the process gas. The electrode plate 17
has a plurality of holes 17a throughout the electrode plate 17. The
cleaning gas and process gas which are diffused by the diffusing
portion are sent to the wafer W through the holes 17a of the
electrode plate 17.
[0045] An annular vent 24 is provided at the bottom of the chamber
11. The vent 24 is connected to the exhaust line L3. The exhaust
line L3 is connected to a TMP (Turbo Molecular Pump) 25. A dry pump
is provided downstream of the TMP 25, so that the chamber 11 can be
decompressed so as to be in a vacuum state. An APC (Automatic
Pressure Controller) 26 is provided between the TMP 25 and the
chamber 11. The chamber 11 is controlled to be in a predetermined
pressure level by the APC 26.
[0046] The system controller 11 controls the processing apparatus
10 totally, including a film formation process and a cleaning
process which are carried out inside the processing apparatus
10.
[0047] The film formation process and cleaning process carried out
by the processing apparatus 10 of the first embodiment will now be
explained with reference to FIG. 1. Those procedures included in
the above processes will be explained below for description
purposes only, and the present invention is not limited to
them.
[0048] The wafer W is carried into the chamber 11, and put on the
susceptor 12. The wafer W is fixed thereon by the electrostatic
chuck. The system controller 100 opens the valve VE so as to supply
O.sub.2, and applies an RF power to the upper electrode (the
electrode plate 17). Subsequently, the system controller 100 opens
the valves VC, VD, and VF, supplies the chamber 11 with SiF.sub.4,
SiH.sub.4, and Ar, and applies a voltage to the lower electrode
(the susceptor 12). From this, plasma of the gas is generated, and
the SiOF film formation reaction undergoes on and over the surface
of the wafer W.
[0049] After the SiOF film having a predetermined thickness is
formed on the wafer W, or after a predetermined time, the system
controller 100 stops applying an RF power to the lower electrode,
and closes the valves VC, VD, and VF, so as to stop supplying the
chamber 11 with SiF.sub.4, SiH.sub.4, and Ar. After this, the
electrostatic chuck is released. The system controller 100 closes
the valve VE so as to stop supplying O.sub.2 and applying an RF
power to the upper electrode. Then, the wafer W is carried out from
the chamber 11, and hence completing the film formation
process.
[0050] After the above-described film formation process is done for
a predetermined number of wafers, the system controller 100 starts
cleaning the chamber 11. A dummy wafer W for cleaning is carried
into the chamber 11, and put on the susceptor 12. The dummy wafer W
put on the susceptor 12 is fixed by the electrostatic chuck. Then,
the system controller 100 opens the valves VA and VB, and supplies
the chamber 11 with NF.sub.3 and Ar.
[0051] A cleaning gas is supplied into the chamber 11 at a ratio of
NF.sub.3/Ar=500/500 (sccm/sccm). The pressure inside the chamber 11
is set to 13Pa by the APC 26.
[0052] After the cleaning gas is thus supplied, the system
controller 100 start applying an RF power to the upper and lower
electrodes, so as to begin the cleaning. Note that applied to the
upper electrode is an RF power of approximately 1500W, and applied
to the lower electrode is an RF power of approximately 500W. Upon
application of the RF power to the cleaning gas, plasma of the gas
especially containing fluorine radical is generated. An NF.sub.3
plasma (containing, mainly, fluorine radical) reacts with SiOF
deposited inside the chamber 1, as explained in the following
formula. As shown in the following formula, SiOF is decomposed by
NF.sub.3, so as to be exhausted as a gas of, for example,
SiH.sub.4, etc.
SiOF+NF.sub.3.fwdarw.SiF.sub.4.Arrow-up bold.+1/2O.sub.2.Arrow-up
bold.+1/2N.sub.2.Arrow-up bold.
[0053] The system controller 100 monitors a light emission of the
plasma generated (for example, of oxygen) during the cleaning
process, and detects the end point of the cleaning. As described
above, O.sub.2 is generated at the same time of the decomposition
of SiOF, and the amount of O.sub.2 changes during the cleaning
process. That is, the system controller 100 can detect the end
point of the cleaning, by monitoring the amount of oxygen (based on
an emission intensity). Note that the end point of the cleaning can
be detected by any other methods, such as a method for detecting
the pressure inside the chamber, etc.
[0054] Upon the end point of the cleaning, the system controller
100 stops applying an RF power to the upper and lower electrodes.
Subsequently, the system controller 100 opens the valves VE and VF,
supplies the chamber 11 with O.sub.2 and Ar, and starts applying an
RF power to the upper electrode. After this, the system controller
100 stops supplying the chamber 11 with Ar and applying the RF
power to the upper electrode. The system controller 100 stops
supplying the chamber 11 with O.sub.2, and releases the
electrostatic chuck. Then, the dummy wafer W is carried out from
the chamber 11, thereby completing the cleaning process.
EXAMPLE 1
[0055] FIGS. 2 and 3 show cleaning results achieved after the film
formation which is done using the plasma processing apparatus 10
according to the first embodiment of the present invention.
[0056] In this Example 1, during a film formation, a SiOF film is
formed to have a thickness of 5 .mu.m on the wafer W, within the
distance 50 mm between the electrodes. In addition, during a
cleaning process, the system controller 100 supplies the chamber 11
with NF.sub.3/Ar=500/500 (sccm/sccm) at a pressure of 13 Pa, and
applies an RF power of 1500W to the upper electrode (the electrode
plate 17).
[0057] FIG. 2 shows the relationship between the cleaning time and
the applied RF power, in the case where the cleaning is performed
with applying the RF power to the upper and lower electrodes using
the processing apparatus of the first embodiment. As seen from FIG.
2, it is clear that the processing apparatus which applies the RF
power to the upper and lower electrodes can achieve the cleaning at
a shorter period of time than the case where the RF power is
applied only to the upper electrode. In the case where RF powers of
300W and 500W are applied to the lower electrode, the cleaning time
is reduced to 76 MIN and 70 MIN, respectively. Accordingly, in the
processing apparatus of this embodiment which performs the cleaning
by applying an RF power not only to the upper electrode, but also
to the lower electrode, a high cleaning rate can be obtained, and
hence enabling to perform the cleaning with high efficiency.
[0058] In the above-described embodiment, the explanations have
been made to the pressure inside the processing apparatus according
to the first embodiment, wherein the pressure inside the chamber 11
is retained approximately at a pressure of 13 Pa. However, the
present invention is not limited to the above, and the cleaning may
be performed at a higher pressure than the above pressure of 13
Pa.
[0059] FIG. 3 shows the relationship between the cleaning time and
the pressure inside the chamber 11. As obvious from FIG. 3, as
compared to the case where the cleaning is done at a pressure of 13
Pa inside the chamber 11, the cleaning time can be reduced in the
case where the pressure is increased to a pressure of 50 Pa.
Accordingly, a high cleaning rate can be obtained by performing the
cleaning at a moderate level of a vacuum inside the chamber 11.
Second Embodiment
[0060] A processing apparatus according to the second embodiment
includes a chamber. Inside the chamber, a SiOF film is formed on a
wafer W using a plasma CVD method, with a process gas containing
SiH.sub.4, SiF.sub.4, and O.sub.2. The SiOF film deposited inside
the chamber after the film formation process is removed using a
cleaning gas including NF.sub.3. The cleaning gas is activated
outside the chamber so as to be used.
[0061] FIG. 4 shows the structure of the processing apparatus 10
according to the second embodiment of the present invention. FIG. 5
is a cross sectional view of the processing apparatus 10. In FIGS.
4 and 5, the same components are identified by the same reference
numerals.
[0062] As shown in FIG. 4, the processing apparatus 10 of the
second embodiment includes a cleaning-gas line L4 provided with an
activator 27.
[0063] The activator 27 is connected to the cleaning gas source SA
and the carrier gas source SB respectively through the valves VA
and VB and also through mass flow controllers MA and MB. The
activator 27 has a plasma generation mechanism. This mechanism
activates the gas passing through the activator 27, so as to
generate plasma of the gas. Of cleaning gas plasmas, a fluorine
radical which is generated from NF.sub.3 is selectively discharged
from the activator 27.
[0064] As shown in FIG. 5, the branched cleaning gas lines L4 is
connected to two cleaning gas inlets 28 which are provided at the
side wall of the chamber 11. The two cleaning gas inlets 28 face
each other at the inner wall of the chamber 11. The cleaning gas
plasma discharged from the activator 27 is introduced into the
chamber 11 through the two cleaning gas inlets 28.
[0065] Operations of the processing apparatus 10 according to the
second embodiment, in the case where the cleaning process is
carried out, will now be explained with reference to FIGS. 4 and 5.
The following operations will now be described by way of example,
and the present invention is not limited to the below.
[0066] After the film is formed on a predetermined number of wafers
W, the system controller 100 begins the cleaning of the chamber
11.
[0067] The dummy wafer W for cleaning is carried into the chamber
11, and put on the susceptor 12. The dummy wafer W on the susceptor
12 is fixed by the electrostatic chuck. Subsequently, the system
controller 100 opens the valves VA and VB, and supplies the chamber
11 with NF.sub.3 and Ar.
[0068] The cleaning gas is supplied into the chamber 11 at a ratio
of NF.sub.3/Ar=500/500 (sccm/sccm). The pressure inside the chamber
11 during the cleaning is retained in a range between 100 Pa and
400 Pa by the APC 26.
[0069] After the NF.sub.3 gas and Ar gas are supplied into the
chamber 11, the system controller 100 activates the activator 27.
The activator 27 activates the supplied gas therein to generate
plasma of the gas, and then discharges the plasma (containing
mainly fluorine radical) to the chamber 11. The SiOF film remaining
and adhered to the inside of the chamber 11 is decomposed to
SiF.sub.4, etc. by the cleaning gas mainly containing the fluorine
radical, so as to be discharged therefrom. Accordingly, the
cleaning is thus proceeded, and the SiOF film deposited inside the
chamber 11 is removed.
[0070] When the system controller 100 determines that the cleaning
has been completed based on the emission intensity of oxygen, it
inactivates the activator 27. Further, the system controller 100
closes the valves VA and VB, so as to stop supplying the chamber 11
with the cleaning gas. After this, the system controller 100 opens
the valves VE and VF, so as to supply O.sub.2 and Ar into the
chamber 11. Subsequently, the system controller 100 releases the
electrostatic chuck, and stops supplying O.sub.2 and Ar into the
chamber 11. After this, the dummy wafer W is carried out from the
chamber 11, thereby completing the cleaning process.
EXAMPLE 2
[0071] FIG. 6 shows the relationship between the time for cleaning
and the pressure inside the chamber 11, and shows some results of
the cleaning done after the film formation, using the processing
apparatus according to the second embodiment of the present
invention. In Example 2, during the process for forming the film, a
SiOF film is formed to have a thickness of 5 .mu.m on the wafer W,
with the distance of 50 mm between the electrodes.
[0072] FIG. 6 shows the results of the cleaning with a variety of
pressure levels. As seen from FIG. 6, as compared to the case where
the pressure inside the chamber 11 is in a high vacuum state of
approximately 0 Pa, a high cleaning rate can be obtained if the
pressure is within a range between 100 Pa and 400 Pa. Note also
that, in the case where the pressure inside the chamber 11 is
approximately 200 Pa, the most highest cleaning rate can be
obtained. According to the second embodiment wherein the cleaning
is performed at a pressure in a range between 100 Pa and 400 Pa
inside the chamber 11, the cleaning can desirably be achieved with
high efficiency.
EXAMPLE 3
[0073] In the above-described second embodiment, an RF power may be
applied to the upper electrode. This realizes that the cleaning gas
(mainly containing fluorine radical) activated outside the chamber
11 can further be activated inside the chamber 11. According to
this structure, a high cleaning rate can be obtained.
[0074] FIG. 7 shows the relationship between the time for cleaning
and the RF power applied onto the upper electrode, in the case
where the cleaning is performed after the SiOF film is formed on
the wafer W in a thickness of 5 .mu.m. During the cleaning, an RF
power of 500W is applied to the upper electrode, and the pressure
inside the chamber 11 is 200 Pa.
[0075] As obvious from FIG. 7, if the RF power is applied to the
upper electrode and a remote plasma gas is used for cleaning the
chamber 11, the cleaning is achieved at a cleaning time which is
shorter than one fifth of the cleaning time in the case where the
RF power is not applied thereto. Accordingly, with applying the RF
power to the upper electrode to activate the cleaning gas in the
chamber 11, the cleaning with a high cleaning rate is possible.
[0076] Note that the cleaning may be performed, while the RF power
is applied not only to the upper electrode, but also to the lower
electrode.
Third Embodiment
[0077] A processing apparatus according to the third embodiment of
the present invention includes a chamber. In this chamber, a SiOF
film is formed on a wafer W using a plasma CVD method, which
employs a process gas containing SiH.sub.4, SiF.sub.4 and O.sub.2.
The SiOF film remaining and adhered to inside of the chamber 11,
after the film formation process, is removed using a cleaning gas
containing NF.sub.3. The cleaning gas is activated outside the
chamber so as to be used.
[0078] The processing apparatus according to the third embodiment
of the present invention has the same structure as that of the
processing apparatus of the second embodiment shown in FIGS. 4 and
5. FIG. 8 shows the structure of the process according to the third
embodiment. In FIG. 8, the same components are identified by the
same reference numerals as those of FIG. 4.
[0079] As shown in FIG. 8, the processing apparatus 10 of this
embodiment includes three cleaning gas inlets 28 at the inner wall
of the chamber 11. The three cleaning gas inlets 28 are connected
to the cleaning gas line L4 respectively. The cleaning gas inlets
28 are provided approximately at equal intervals. The cleaning gas
is supplied into the chamber 11 through each of the cleaning gas
inlets 28 substantially at the same supply pressure.
EXAMPLE 4
[0080] FIG. 9 shows results of film formation processes and
cleaning processes done by the processing apparatus of the third
embodiment. In FIG. 9, comparisons are made to the cleaning results
done by the processing apparatus of this embodiment. Specifically,
the comparisons are made to one case where the cleaning gas spouts
in two ways, and the other case where the cleaning gas spouts into
the chamber 11 in three ways.
[0081] In the process for forming the film, a SiOF film is formed
in a thickness of 5 .mu.m on the wafer W with the distance of 50 mm
between the electrodes. In the cleaning process, the cleaning gas
of NF.sub.3/Ar=1000/1000 (sccm/sccm) is supplied into and through
the chamber 11 at a pressure of 13 Pa.
[0082] In an experiment, a plurality of chips on each of which a
silicon oxide film is formed are provided respectively on a
plurality of points inside the chamber 11. The thickness of the
silicon oxide film of each of the chips is measured after cleaning.
The cleaning rate at each of the points in the chamber 11 is
calculated, based on a reduction in the measured thickness of the
silicon oxide film.
[0083] The points for measuring the cleaning rate are identified by
symbols of I to V, as illustrated in FIG. 8. For the processing
apparatus 10 wherein the cleaning gas spouts in two ways, the
cleaning rate is measured at each of the points I to V, as shown in
FIG. 10. The chip at the point I is put on the susceptor 12, and
the rest of the chips respectively at the points II to V are put on
almost the same plane as the susceptor 12.
[0084] As seen from FIG. 9, in the case where the cleaning gas is
supplied from two points (in two ways), the cleaning rate at the
point II, which is farthest from the cleaning gas inlets 28, is
lower than the cleaning rate at any other points I, III, IV, and V.
In the third embodiment wherein the cleaning gas is supplied from
three points (in three ways), the etching rate at the point II is
almost equal to or larger than the etching rate at any other points
I, III, IV, and V. In consideration of this, in the processing
apparatus 10 of the third embodiment thus including the three
cleaning gas inlets 28 in the chamber 11, the uniformity of the
cleaning rate can be obtained, and the cleaning is performed with
high efficiency.
[0085] In the above-described third embodiment, the three cleaning
gas inlets 28 are provided at equal intervals on the side wall of
the chamber 11. However, the cleaning gas inlets 28 may be provided
at any other intervals. Further, the number of the cleaning gas
inlets 28 is not limited to three, and more than three cleaning gas
inlets may be provided.
Fourth Embodiment
[0086] A processing apparatus according to the fourth embodiment of
the present invention includes a chamber. In this chamber, a SiOF
film is formed on a wafer using a plasma CVD method, which employs
a process gas containing SiH.sub.4, SiF.sub.4, and O.sub.2. The
SiOF film remaining in and adhered to the inside of the chamber
after the film formation process is removed by a cleaning gas
containing NF.sub.3. The cleaning gas is activated outside the
chamber, so as to be used.
[0087] The processing apparatus according to the fourth embodiment
of the present invention has the same structure as that of the
process according to the third embodiment shown in FIGS. 5 and 8.
In the processing apparatus 10 of the fourth embodiment, a lid
member 29 shown in FIG. 11 is built on each of the three cleaning
gas inlets 28. In this structure, the cleaning gas is introduced
into the chamber 11 through the lid member 29.
[0088] As illustrated in FIG. 11, the lid member 29 is formed in a
rectangular shape, and has five slit-like openings 30. Those five
openings 30 are formed in parallel with each other. The size of the
lid member 29 is approximately the same as the section of each of
the cleaning gas inlets 28. The cleaning gas is supplied into the
chamber 11 through the openings 30. The lid member 29 is made of
Al.sub.2O.sub.3, for example.
[0089] The opening percentage of the lid member 29 is set in a
range from 50% to 80%. Note that the opening percentage in this
case implies a ratio of the entire area of the openings 30 included
in the lid member 29 to the entire area of the lid member 29, i.e.
(Opening (%))=(Entire Area of Openings 30)/(Entire Area of Lid
Member 29).times.100.
EXAMPLE 5
[0090] FIG. 12 shows results of cleaning experiments done using the
processing apparatus 10 according to the fourth embodiment of the
present invention.
[0091] The cleaning experiments are performed in the same manner as
that of the Example 4. In the film formation process, a SiOF film
is formed in a thickness of 5 .mu.m on the wafer W, with the
distance of 50 mm between the electrodes. In the cleaning process,
the cleaning gas is supplied at a ratio of NF.sub.3/Ar=1000/1000
(sccm/sccm) and pressure of 13 Pa inside the chamber 11.
[0092] The opening percentage of the lid member 29 is set to 62%.
For comparison, the cleaning experiments are done using a plurality
of lid members 29 whose opening percentages are 10%, 35%, and 100%,
respectively.
[0093] Likewise the Example 4, in the cleaning experiments, chips
on each of which a silicon oxide film is formed are provided at
each of the points inside the chamber 11. The thickness of the
silicon oxide film is measured. The cleaning rate at each of the
points is obtained by calculating a reduction in the thickness of
the silicon oxide film.
[0094] The points for measuring the cleaning rate are identified by
symbols of I to V, as shown in FIG. 8. Note that the chip at the
point I is put on the susceptor 12, and the rest of the chips at
the points II to V are provided on the same plane as the susceptor
12.
[0095] As seen from FIG. 12, if the opening percentage of the lid
member 29 is 100%, the cleaning rates respectively at the points I
to V widely vary. If the opening percentage of the lid member 29 is
10% or 35%, the cleaning rates thereat are quite uniform. However,
such cleaning rates, in the case of 10% or 35% of the opening
percentage, are not sufficiently high. Alternatively, according to
the processing apparatus of the fourth embodiment using the lid
member 29 whose opening percentage is 62%, nearly-uniform cleaning
rates are highly obtained at each of the points I to V inside the
chamber 11.
[0096] Accordingly, in the processing apparatus 10 of this
embodiment using the lid member 29 whose opening percentage is in a
range from 50% to 80%, sufficiently high cleaning rates can be
obtained. In addition, the cleaning gas can be supplied into the
chamber 11 with uniformity.
[0097] In the fourth embodiment, the openings 30 of the lid member
29 are formed in a slit-like shape. However, the shape of the
openings 30 is not limited to this. For example, the openings 30
may be formed in a circular shape, a polygonal shape, or any other
shapes. Further, the plurality of slit-shaped openings 30 may be
included in parallel with each other. In addition, the shape of the
lid member 29 is not limited to the rectangular shape, and the lid
member 29 may be formed in a circular shape in conformity with the
section of the cleaning gas inlets 28.
[0098] In the fourth embodiment, the openings 30 of the lid member
29 may be set at a variety of angles, respectively, as shown in
FIG. 13. In this structure, the cleaning gas can uniformly spout
into the chamber 11.
[0099] FIG. 13 shows a state wherein the lid member 29 of FIG. 11
is fixed into the cleaning gas inlet 28. Of five openings 30 of the
lid member 29, a central opening 30a forms a path perpendicular to
the main surface of the lid member 29. Openings 30b and 30c, except
the central opening 30a, form paths diagonally to the 30 main
surface. Specifically, the two openings 30b adjacent to the central
opening 30a form paths at an angle of 60.degree. with the main
surface, whereas the two end openings 30c form paths at an angle of
45.degree. therewith.
[0100] In the structure where the lid member 29 includes the
openings 30b and 30c forming the paths diagonally to the main
surface, the cleaning gas diagonally spouts from the openings 30b
and 30c. Hence, the gas spouts evenly from the cleaning gas inlet
28.
EXAMPLE 6
[0101] FIG. 14 shows results of cleaning experiments achieved using
the processing apparatus 10 according to the fourth embodiment,
including the lid member 29 of FIG. 13.
[0102] Those cleaning experiments are done in accordance with the
same steps as those of the Example 4. In the film formation
process, the SiOF film of 5 .mu.m is formed on the wafer W, with
the distance of 50 mm between the electrodes. In the cleaning
process, the cleaning gas flows into and through the chamber, at a
ratio of NF.sub.3/Ar=1000/1000 (sccm/sccm) and at a pressure of 13
Pa inside the chamber 11.
[0103] The opening percentage of the lid member 29 is set to 35%.
For comparison, the same cleaning experiment as the experiment of
the Example 4 is performed using the lid member 29 including only
the vertical openings 30a of FIG. 15.
[0104] Likewise the Example 4, in the experiments, the chip on
which a silicon oxide film is formed is provided on each of the
points inside the chamber 11, and the thickness of the silicon
oxide film is measured. The cleaning rate at each of the points is
calculated by measuring the reduction in the thickness of the
silicon oxide film.
[0105] The points for measuring the cleaning rate are identified by
the symbols of I to V shown in FIG. 8. The chip at the point I is
put on the susceptor 12, and the rest of the chips at the
respective points II to V are provided almost on the same plane as
the susceptor 12.
[0106] As obvious from FIG. 14, in the case where the lid member 29
including only the vertical openings 30a is used, the cleaning rate
is the lowest at the point III, and the cleaning rate widely vary
at each points I to V. In the case where the lid member 29
including the diagonal openings 30b and 30c is used, the cleaning
rates are approximately the same at the respective points II to V,
i.e. except at the point I (on the susceptor 12). Accordingly, with
the utilization of the chamber 29 including the openings 30b and
30c forming the paths at predetermined angles (e.g. 45.degree.,
60.degree.), the cleaning gas is supplied in different directions
into the chamber 11, thereby enabling to evenly clean the inside of
the chamber 11.
[0107] In the above examples, the angles of the paths from the
diagonal openings 30b and 30c are not limited to 45.degree. and
60.degree., and may be 70.degree., 30.degree., etc. In addition, in
accordance with the number of the openings 30, the angles of the
paths from the openings 30 may be changed. For example, if the
number of the openings 30 is seven, the seven openings 30 may form
paths having respectively an angle of 90.degree., 60.degree.,
45.degree., and 30.degree., sequentially from the central one to
both end openings.
Fifth Embodiment
[0108] A processing apparatus according to the fifth embodiment of
the present invention includes a chamber. In this chamber, a SiOF
film is on a wafer W using a plasma CVD method, which employs a
process gas containing SiH.sub.4, SiF.sub.4 and O.sub.2. The SiOF
film remaining and adhered to the inside of the chamber 11 is
removed using a cleaning gas containing NF.sub.3. This cleaning gas
is activated outside the chamber 11 so as to be used.
[0109] The processing apparatus according to the fifth embodiment
of the present invention has the same structure as that of the
processing apparatus of the second embodiment which is shown in
FIG. 4. In the processing apparatus according to the fifth
embodiment, the chamber 11 is connected to the process gas line L1,
the exhaust line L3, and the cleaning gas line L4.
[0110] FIG. 16 shows the processing apparatus 10 according to the
fifth embodiment, in section. In FIG. 16, the same components are
identified by the same reference numerals as those of FIG. 5. For
the sake of simplicity, the gas lines and RF power sources are not
illustrated in FIG. 16.
[0111] In the processing apparatus 10 shown in FIG. 16, chiller
paths 31 are embedded in the electrode supporter 18 and the side
wall of chamber 11. A chiller flows through the chiller paths 31,
thereby the internal surface of the chamber 11, especially the
electrode plate 17 supported by the electrode supporter 18 and the
wall of the chamber 11, are retained at a predetermined
temperature. In the cleaning process, the system controller 100
controls the flow system of the chiller so as to adjust the
temperature of the chamber 11. In this specification, the term,
chiller, implies a fluid material for maintaining the temperature
of an object, but not for simply cooling (chilling) an object. The
inside of the chamber 11 which is in a vacuum state is thus
essentially retained at a very low temperature, so that the
electrode plate 17, etc. is substantially heated up by the
chiller.
[0112] The electrode plate 17 has a plurality of holes 17a for
introducing the process gas into the chamber 11. In this structure,
the electrode plate 17 is one component onto which the film is most
likely to be adhered, and hence is one component which should
firstly be cleaned among of the chamber member. Because of the
structure that the electrode plate 17 includes the plurality of
holes 17a, the electrode plate 17 can not easily be cleaned. By
heating the electrode plate 17 using the chiller, the cleaning rate
of the electrode plate 17 can partially be enhanced.
EXAMPLE 7
[0113] The cleaning process is carried out on the following
conditions, using the processing apparatus 10 of this embodiment
which includes the lid member 29. In the film formation process, a
SiOF film is formed in a thickness of 5 .mu.m on a wafer W with the
distance of 50 mm between the electrodes. In the cleaning process,
the cleaning gas at a ration of NF.sub.3/Ar=1000/1000 (sccm/sccm)
flows at a pressure of 13 Pa into the chamber 11. The temperature
of the chiller flowing into the electrode supporter 18 and wall of
the chamber 11 is set to 100.degree. C. To obtain the experimental
outcome, the chip on which the silicon oxide film is formed is
provided on the electrode plate 17, and a reduction in the
thickness of the silicon oxide film is measured.
[0114] FIG. 17 shows such experimental results. As seen from FIG.
17, as compared to the case where the electrode plate 17 is not
heated, a high cleaning rate at the electrode plate 17 can be
obtained in the case where the electrode plate 17 is heated.
According to the processing apparatus of the fifth embodiment,
wherein the electrode plate 17 is heated, the cleaning rate can be
enhanced at the electrode plate 17 which is difficult to
sufficiently be cleaned, thus enabling to evenly perform the
cleaning of the chamber 11. Further, by heating the wall of the
chamber 11, the cleaning rate can highly be obtained throughout the
chamber 11.
[0115] In the fifth embodiment, the walls of the electrode plate 17
and chamber 11 are heated by the chiller. However, the wall may be
heated using any other methods.
[0116] For example, as shown in FIG. 18, instead of the chiller
paths 31, a heater 32, such as a resistor, etc. may be included in
the chamber 11.
[0117] As shown in FIG. 19, the walls of the electrode plate 17 and
chamber 11 may be heated by a lamp 33, such as a halogen lamp, etc.
In this case, a window 34 may be prepared on the side surface of
the chamber 11, so that the electrode plate 17, etc. is heated by
irradiating light thereto from the lamp 33 through the window
34.
[0118] FIG. 17 also shows results of cleaning experiments,
respectively in the cases where the electrode plate 17 is heated by
the heater 32 shown in FIG. 18 and heated by the lamp 33 shown in
FIG. 19, in addition to the cases where the electrode plate 17 is
not heated and is heated by the chiller. The heater 32 and the lamp
33 are set at 100.degree. C.
[0119] As seen from FIG. 17, the electrode plate 17 is heated by
the heater 32 or the lamp 33, to obtain a high cleaning rate at the
electrode plate 17. Accordingly, the electrode plate 17 is heated,
thereby enhancing the cleaning rate at the electrode plate 17 which
can not sufficiently be cleaned.
[0120] In the fifth embodiment of the present invention, the
temperature of the heater 32 or lamp 33 is set at 100.degree. C.
However, the temperature is not limited to 100.degree. C., as long
as the cleaning inside the chamber 11 can evenly be achieved.
[0121] In the above-described first to fifth embodiments, the SiOF
film is formed on the wafer W, and the cleaning of the chamber 11
is done using an NF.sub.3 gas, in the parallel-plate-type plasma
processing apparatus 10. However, the film to be formed is not
limited to the SiOF film, and a silicon-containing film, such as
SiO.sub.2, SiC, SiN, SiCN, SiCH, SiOCH, etc. may be formed. The
cleaning gas may include, not only the NF.sub.3 gas, but a
fluorine-containing gas, such as CF.sub.4, C.sub.2F.sub.6,
SF.sub.6, etc., or a chlorine-containing gas, such as Cl.sub.2,
BCl.sub.4, etc. The present invention may also be applied to a
processing apparatus wherein LCD (Liquid Crystal Display) devices
are processed.
[0122] In the second to fifth embodiments, the cleaning gas is
activated so as to generate plasma of the cleaning gas, especially
containing radicals. However, by activating the cleaning gas, the
active species, other than the radicals, may be employed, so as to
perform the cleaning of the chamber.
[0123] The present invention according to the second to fifth
embodiments is applicable, not only to the parallel-plate-type
plasma processing apparatus, but any other type of plasma
processing apparatus, such as an ECR-type processing apparatus, an
ICP-type processing apparatus, a helicon-type processing apparatus,
a micro-wave-type processing apparatus, etc. In addition, the
present invention is applicable not only to the plasma processing
apparatus, but any other processing apparatus, such an etching
apparatus, a sputtering apparatus, a heat processing apparatus,
etc.
Industrial Applicability
[0124] The present invention mentioned above is useful for
manufacturing semiconductor products.
[0125] This application is based on Japanese Patent Application No.
2000-239426 filed on Aug. 8, 2000 and including specification,
claims, drawings and summary. The disclosure of the above Japanese
Patent Application is incorporated herein by reference in its
entirety.
* * * * *