U.S. patent application number 13/344926 was filed with the patent office on 2012-07-12 for focus ring and substrate processing apparatus having same.
This patent application is currently assigned to TOKYO ELECTRON LIMITED. Invention is credited to Chishio Koshimizu, Jun Yamawaku.
Application Number | 20120176692 13/344926 |
Document ID | / |
Family ID | 46455042 |
Filed Date | 2012-07-12 |
United States Patent
Application |
20120176692 |
Kind Code |
A1 |
Yamawaku; Jun ; et
al. |
July 12, 2012 |
FOCUS RING AND SUBSTRATE PROCESSING APPARATUS HAVING SAME
Abstract
There is provided a focus ring that is capable of preventing
deposits from adhering to a member having a lower temperature in a
gap between two members having different temperatures. A focus ring
25 is disposed to surround a peripheral portion of a wafer W in a
chamber 11 of a substrate processing apparatus 10. The focus ring
25 includes an inner focus ring 25a and an outer focus ring 25b.
Here, the inner focus ring 25a is placed adjacent to the wafer W
and configured to be cooled; and the outer focus ring 25b is placed
so as to surround the inner focus ring 25a and configured not to be
cooled. Further, a block member 25c is provided in a gap between
the inner focus ring 25a and the outer focus ring 25b.
Inventors: |
Yamawaku; Jun; (Nirasaki,
JP) ; Koshimizu; Chishio; (Nirasaki, JP) |
Assignee: |
TOKYO ELECTRON LIMITED
Tokyo
JP
|
Family ID: |
46455042 |
Appl. No.: |
13/344926 |
Filed: |
January 6, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61435086 |
Jan 21, 2011 |
|
|
|
Current U.S.
Class: |
359/825 ;
156/345.37 |
Current CPC
Class: |
H01J 37/32724 20130101;
H01J 37/32642 20130101 |
Class at
Publication: |
359/825 ;
156/345.37 |
International
Class: |
G02B 7/04 20060101
G02B007/04; H01L 21/306 20060101 H01L021/306 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 7, 2011 |
JP |
2011-002250 |
Claims
1. A focus ring disposed to surround a peripheral portion of a
substrate in a processing chamber of a substrate processing
apparatus, the focus ring comprising: an inner focus ring placed
adjacent to the substrate and configured to be cooled; an outer
focus ring placed so as to surround the inner focus ring and
configured not to be cooled; and a quartz member placed in a gap
between the inner focus ring and the outer focus ring.
2. The focus ring of claim 1, wherein the quartz member is exposed
to a processing space in which plasma is generated within the
processing chamber.
3. The focus ring of claim 1, wherein a mounting table for mounting
thereon the substrate and the inner focus ring is provided within
the processing chamber, and the quartz member is extended to be
placed between the inner focus ring and the mounting table.
4. A substrate processing apparatus comprising: a processing
chamber for accommodating a substrate therein; and a focus ring
disposed to surround a peripheral portion of a substrate in the
processing chamber, wherein the focus ring comprises: an inner
focus ring placed adjacent to the substrate and configured to be
cooled; an outer focus ring placed so as to surround the inner
focus ring and configured not to be cooled; and a quartz member
placed in a gap between the inner focus ring and the outer focus
ring.
5. A substrate processing apparatus comprising: a processing
chamber for accommodating a substrate therein; a focus ring
configured to surround a peripheral portion of the substrate
disposed in the processing chamber; and a mounting table for
mounting thereon the substrate and the focus ring, wherein the
focus ring comprises: an inner focus ring placed adjacent to the
substrate and configured to be cooled; and an outer focus ring
placed so as to surround the inner focus ring and configured not to
be cooled, the mounting table is configured to be cooled such that
a temperature of the mounting table becomes lower than that of the
inner focus ring, and a quartz member is placed in a gap between
the inner focus ring and the mounting table.
6. The substrate processing apparatus of claim 5, wherein the
quartz member is placed between the inner focus ring and a mounting
surface of the mounting table on which the inner focus ring is
mounted.
7. The substrate processing apparatus of claim 6, wherein the
quartz member is extended to be placed in a gap between the inner
focus ring and the outer focus ring.
8. The substrate processing apparatus of claim 6, wherein a quartz
member is further provided in a gap between the inner focus ring
and the outer focus ring.
9. A substrate processing apparatus comprising: a processing
chamber for accommodating a substrate therein; a focus ring
disposed to surround a peripheral portion of the substrate in the
processing chamber; a mounting table for mounting thereon the
substrate and the focus ring; and a gas supply unit configured to
supply a gas into a gap between the focus ring and the mounting
table, wherein the focus ring comprises an inner focus ring placed
adjacent to the substrate and configured to be cooled; and an outer
focus ring placed so as to surround the inner focus ring and
configured not to be cooled, and the gas supply unit is configured
to supply the gas into at least one of a gap between the inner
focus ring and the outer focus ring and a gap between the inner
focus ring and the mounting table.
10. The substrate processing apparatus of claim 9, wherein the gas
supplied by the gas supply unit includes an oxygen gas.
11. The substrate processing apparatus of claim 9, wherein the gas
supplied by the gas supply unit is an inert gas.
12. The substrate processing apparatus of claim 9, wherein the gas
supplied by the gas supply unit is a processing gas.
13. A focus ring disposed to surround a peripheral portion of a
substrate in a processing chamber of a substrate processing
apparatus, the focus ring comprising: an inner focus ring placed
adjacent to the substrate and configured to be cooled; and an outer
focus ring placed so as to surround the inner focus ring and
configured not to be cooled, wherein the inner focus ring has a
thin-plate shape flange exposed to a processing space within the
processing chamber and protruded so as to cover a part of the outer
focus ring.
14. The focus ring of claim 13, wherein the flange of the inner
focus ring has a thickness ranging from about 1.7 mm to about 2.0
mm.
15. A substrate processing apparatus comprising: a processing
chamber for accommodating a substrate therein; and a focus ring
disposed to surround a peripheral portion of the substrate in the
processing chamber, wherein the focus ring comprises: an inner
focus ring placed adjacent to the substrate and configured to be
cooled; and an outer focus ring placed so as to surround the inner
focus ring and configured not to be cooled, and the inner focus
ring has a thin-plate shape flange exposed to a processing space
within the processing chamber and protruded so as to cover a part
of the outer focus ring.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of Japanese Patent
Application No. 2011-002250 filed on Jan. 7, 2011, and U.S.
Provisional Application Ser. No. 61/435,086 filed on Jan. 21, 2011,
the entire disclosures of which are incorporated herein by
reference.
FIELD OF THE INVENTION
[0002] The present disclosure relates to a focus ring and a
substrate processing apparatus having the focus ring.
BACKGROUND OF THE INVENTION
[0003] Recently, as a semiconductor wafer (hereinafter, simply
referred to as a "wafer"), on which semiconductor devices is to be
formed, is scaled up, it has been required to manufacture
semiconductor devices even on a peripheral region of the wafer W,
e.g., on a range within about 10 mm from an edge of the wafer
toward a center thereof. Usually, a temperature distribution of the
wafer affects a distribution of radicals in plasma by which a
plasma process is performed on the wafer. Thus, in order to perform
a uniform plasma process on the entire region of the wafer, the
temperature of the peripheral region of the wafer needs to be
controlled to be substantially the same as the temperature of the
other region of the wafer. For the purpose, conventionally, there
has been developed a technique for controlling the temperature of
the focus ring to cool the focus ring in order to reduce radiant
heat from the focus ring.
[0004] However, if the entire wafer temperature becomes lower as
the focus ring is cooled, a resist film coated on the wafer as a
pattern mask is easily etched by the plasma. Thus, in order to
prevent a great decrease of the entire wafer temperature, the
present applicant has developed a technique in which a first focus
ring (hereinafter, referred to as an "inner focus ring") is
provided and a second focus ring (hereinafter, referred to as an
"outer focus ring") is placed at an outside of the first focus
ring, and the first focus ring is cooled whereas the outer focus
ring is not cooled but it is rather heated (see, for example,
Patent Document 1).
[0005] Patent Document 1: US Patent Publication No. US 2010/0213171
A1
[0006] Generally, in a gap between two members having greatly
different temperatures, deposits are likely to adhere to a member
having a lower temperature. Actually, the present inventor has
found out that, when the aforementioned so-called dual focus ring
including the inner focus ring and the outer focus ring is used,
deposits tends to easily adhere to the inner focus ring in a gap
between the inner and outer focus rings
[0007] Since the gap between the inner focus ring and the outer
focus ring is narrow and the plasma cannot be introduced into the
gap easily, it is difficult to remove the deposits adhering to the
inner focus ring by asking or the like. Thus, in order to remove
the deposits from the inner focus ring, it is required that a
chamber is opened to the atmosphere and the inner focus ring is
taken out. As a result, an operation rate of a substrate processing
apparatus including the focus ring would be deteriorated.
[0008] Further, in the substrate processing apparatus, a susceptor
on which the inner focus ring or the outer focus ring are mounted
is cooled to a temperature lower than the temperature of the inner
focus ring. Accordingly, a temperature difference between the inner
focus ring and the susceptor is increased. As a result, deposits
adhere to the susceptor in a gap between the inner focus ring and
the susceptor.
[0009] Since the gap between the focus ring and the susceptor is
also narrow, in order to remove the deposits from the susceptor, it
is required the chamber is opened to the atmosphere and the inner
focus ring is taken out to expose the susceptor. As a result, the
operation rate of the substrate processing apparatus would be also
deteriorated.
BRIEF SUMMARY OF THE INVENTION
[0010] In view of the foregoing problems, the present disclosure
provides a focus ring capable of preventing deposits from adhering
to a member having a lower temperature in a gap between two members
having different temperatures. Further, the present disclosure also
provides a substrate processing apparatus having this focus
ring.
[0011] In accordance with one aspect of the present disclosure,
there is provided a focus ring disposed to surround a peripheral
portion of a substrate in a processing chamber of a substrate
processing apparatus. The focus ring includes an inner focus ring
placed adjacent to the substrate and configured to be cooled; an
outer focus ring placed so as to surround the inner focus ring and
configured not to be cooled; and a quartz member placed in a gap
between the inner focus ring and the outer focus ring.
[0012] Further, the quartz member may be exposed to a processing
space in which plasma is generated within the processing
chamber.
[0013] Here, a mounting table for mounting thereon the substrate
and the inner focus ring may be provided within the processing
chamber, and the quartz member may be extended to be placed between
the inner focus ring and the mounting table.
[0014] In accordance with another aspect of the present disclosure,
there is provided a substrate processing apparatus that includes a
processing chamber for accommodating a substrate therein; and a
focus ring disposed to surround a peripheral portion of a substrate
in the processing chamber. Here, the focus ring includes an inner
focus ring placed adjacent to the substrate and configured to be
cooled; an outer focus ring placed so as to surround the inner
focus ring and configured not to be cooled; and a quartz member
placed in a gap between the inner focus ring and the outer focus
ring.
[0015] In accordance with still another aspect of the present
disclosure, there is provided a substrate processing apparatus that
includes a processing chamber for accommodating a substrate
therein; a focus ring configured to surround a peripheral portion
of the substrate disposed in the processing chamber; and a mounting
table for mounting thereon the substrate and the focus ring. Here,
the focus ring includes an inner focus ring placed adjacent to the
substrate and configured to be cooled, and an outer focus ring
placed so as to surround the inner focus ring and configured not to
be cooled. Further, the mounting table is configured to be cooled
such that a temperature of the mounting table becomes lower than
that of the inner focus ring, and a quartz member is placed in a
gap between the inner focus ring and the mounting table.
[0016] In the substrate processing apparatus, the quartz member may
be placed between the inner focus ring and a mounting surface of
the mounting table on which the inner focus ring is mounted.
[0017] Further, the quartz member may be extended to be placed in a
gap between the inner focus ring and the outer focus ring.
Alternatively, a quartz member may be further provided in a gap
between the inner focus ring and the outer focus ring.
[0018] In accordance with still another aspect of the present
disclosure, there is provided a processing chamber for
accommodating a substrate therein; a focus ring disposed to
surround a peripheral portion of the substrate in the processing
chamber; a mounting table for mounting thereon the substrate and
the focus ring; and a gas supply unit configured to supply a gas
into a gap between the focus ring and the mounting table. Here, the
focus ring includes an inner focus ring placed adjacent to the
substrate and configured to be cooled; and an outer focus ring
placed so as to surround the inner focus ring and configured not to
be cooled. Further, the gas supply unit is configured to supply the
gas into at least one of a gap between the inner focus ring and the
outer focus ring and a gap between the inner focus ring and the
mounting table.
[0019] The gas supplied by the gas supply unit may include an
oxygen gas.
[0020] The gas supplied by the gas supply unit may be an inert
gas.
[0021] The gas supplied by the gas supply unit may be a processing
gas.
[0022] In accordance with still another aspect of the present
disclosure, there is provided a focus ring disposed to surround a
peripheral portion of a substrate in a processing chamber of a
substrate processing apparatus. The focus ring includes an inner
focus ring placed adjacent to the substrate and configured to be
cooled; and an outer focus ring placed so as to surround the inner
focus ring and configured not to be cooled. Here, the inner focus
ring has a thin-plate shape flange exposed to a processing space
within the processing chamber and protruded so as to cover a part
of the outer focus ring.
[0023] The flange of the inner focus ring may have a thickness
ranging from about 1.7 mm to about 2.0 mm.
[0024] In accordance with still another aspect of the present
disclosure, there is provided a substrate processing apparatus that
includes a processing chamber for accommodating a substrate
therein; and a focus ring disposed to surround a peripheral portion
of the substrate in the processing chamber. Here, the focus ring
includes an inner focus ring placed adjacent to the substrate and
configured to be cooled; and an outer focus ring placed so as to
surround the inner focus ring and configured not to be cooled; and
the inner focus ring has a thin-plate shape flange exposed to a
processing space within the processing chamber and protruded so as
to cover a part of the outer focus ring.
[0025] In accordance with the present disclosure, since the quartz
member is disposed between the inner focus ring and the outer focus
ring, the oxygen radicals are generated when the plasma comes into
contact with the quartz member in the gap between the inner focus
ring and the outer focus ring. The oxygen radicals may easily
decompose and remove deposits, so that it can be prevented that the
deposits adhere to the inner focus ring having a lower temperature
in the gap between the inner focus ring and the outer focus ring of
which temperatures are greatly different.
[0026] Further, in accordance with the present disclosure, since
the quartz member is disposed between the inner focus ring and the
mounting table, the oxygen radicals are generated when the plasma
comes into contact with the quartz member in the gap between the
inner focus ring and the mounting table. The oxygen radicals may
easily decompose and remove deposits, so that it can be prevented
that the deposits adhere to the mounting table having a lower
temperature in the gap between the inner focus ring and the
mounting table of which temperatures are greatly different.
[0027] Moreover, in accordance with the present disclosure, since
the gas supply unit supplies the gas into at least one of the gap
between the inner focus ring and the outer focus ring and the gap
between the inner focus ring and the mounting table, the supplied
gas may push out reaction products, as a source of deposits, that
have entered the gap between the inner focus ring and the outer
focus ring or the gap between the inner focus ring and the mounting
table. Accordingly, it may be possible to prevent deposits from
adhering to the inner focus ring having the lower temperature in
the gap between the inner focus ring and the outer focus ring of
which temperatures are greatly different. Likewise, it may also be
possible to prevent deposits from adhering to the mounting table
having the lower temperature in the gap between the inner ring and
the mounting table of which temperatures are greatly different.
[0028] In addition, in accordance with the present disclosure, the
inner focus ring has the thin-plate shape flange exposed to the
processing space within the processing chamber and protruded so as
to cover the outer focus ring. Therefore, the temperature of the
flange may be increased by receiving radiant heat from the plasma
in the processing space, so that a temperature difference between
the inner focus ring and the outer focus ring can be reduced in the
vicinity of the flange. As a result, at least in the vicinity of
the flange, it may be possible to prevent deposits from adhering to
the inner focus ring having the lower temperature in the gap
between the inner focus ring and the outer focus ring.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] Non-limiting and non-exhaustive embodiments will be
described in conjunction with the accompanying drawings.
Understanding that these drawings depict only several embodiments
in accordance with the disclosure and are, therefore, not to be
intended to limit its scope, the disclosure will be described with
specificity and detail through use of the accompanying drawings, in
which:
[0030] FIG. 1 is a schematic configuration view of a substrate
processing apparatus in accordance with a first embodiment of the
present disclosure;
[0031] FIG. 2 provides enlarged cross sectional views schematically
illustrating configurations of a focus ring in the substrate
processing apparatus of FIG. 1; FIG. 2(A) shows a focus ring in
accordance with the first embodiment of the present disclosure;
FIG. 2(B), a first modification example of the focus ring in
accordance with the first embodiment; FIG. 2(C), a second
modification example of the focus ring in accordance with the first
embodiment; FIG. 2(D), a third modification example of the focus
ring in accordance with the first embodiment; FIG. 2(E), a fourth
modification example of the focus ring in accordance with the first
embodiment; and FIG. 2(F), a fifth modification example of the
focus ring in accordance with the first embodiment;
[0032] FIG. 3 provides an enlarged cross sectional views
schematically illustrating configurations of a focus ring in a
substrate processing apparatus in accordance with a second
embodiment of the present disclosure; FIG. 3(A) shows a focus ring
in accordance with the second embodiment of the present disclosure;
FIG. 3(B), a first modification example of the focus ring in
accordance with the second embodiment; FIG. 3(C), a second
modification example of the focus ring in accordance with the
second embodiment; and FIG. 3(D), a third modification example of
the focus ring in accordance with the second embodiment;
[0033] FIG. 4 provides enlarged cross sectional views schematically
illustrating configurations of a focus ring in a substrate
processing apparatus in accordance with a third embodiment of the
present disclosure; FIG. 4(A) shows a focus ring in accordance with
the third embodiment of the present disclosure and FIG. 4(B) shows
a first modification example of the focus ring in accordance with
the third embodiment;
[0034] FIG. 5 is an enlarged cross sectional view schematically
illustrating a configuration of a focus ring in a substrate
processing apparatus in accordance with a fourth embodiment of the
present disclosure;
[0035] FIG. 6 provides enlarged cross sectional views illustrating
a configuration in the vicinity of a focus ring in a substrate
processing apparatus capable of removing an attached deposit; FIG.
6(A) depicts a first example and FIG. 6(B) depicts a second
example;
[0036] FIG. 7 provides enlarged cross sectional views illustrating
a configuration in the vicinity of a focus ring in a substrate
processing apparatus capable of removing an attached deposit; FIG.
7(A) depicts a third example and FIG. 7(B) depicts a fourth
example; and
[0037] FIG. 8 provides enlarged cross sectional views illustrating
a configuration in the vicinity of a focus ring included in a
substrate processing apparatus capable of removing an attached
deposit; FIG. 8(A) depicts a fifth example; FIG. 8(B), a sixth
example; FIG. 8(C), a seventh example; and FIG. 8(D), an eighth
example.
DETAILED DESCRIPTION OF THE INVENTION
[0038] Hereinafter, illustrative embodiments of the present
disclosure will be described with reference to the accompanying
drawings.
[0039] First, a substrate processing apparatus in accordance with a
first embodiment of the present disclosure will be explained.
[0040] FIG. 1 is a schematic configuration view of the substrate
processing apparatus in accordance with the first embodiment. The
substrate processing apparatus is configured to perform a plasma
etching process on a wafer as a substrate for a semiconductor
device (hereinafter, simply referred to as a "wafer").
[0041] Referring to FIG. 1, a substrate processing apparatus 10
includes a chamber 11 for accommodating therein a wafer W having a
diameter of, e.g., about 300 mm. A circular column-shaped susceptor
12 (mounting table) for mounting thereon the wafer W is provided in
the chamber 11. In this substrate processing apparatus 10, a side
exhaust path 13 is formed between an inner sidewall of the chamber
11 and a side surface of the susceptor 12. An exhaust plate 14 is
provided on the way of the side exhaust path 13.
[0042] The exhaust plate 14 is a plate-shaped member having a
multiple number of through holes. The exhaust plate 14 serves as a
partition plate that partitions an inside of the chamber 11 into an
upper portion and a lower portion. As will be described later,
plasma is generated in an inner space (processing space) within the
upper portion 15 (hereinafter, referred to as a "processing
chamber") of the chamber 11 above the exhaust plate 14. Further, an
exhaust pipe 17 for exhausting a gas within the chamber 11 is
connected to the lower portion 16 (hereinafter, referred to as an
"exhaust chamber (manifold)") of the inside of the chamber 11 below
the exhaust plate 14. The exhaust plate 14 confines or reflects the
plasma generated in the processing chamber 15, thus preventing
leakage of the plasma into the manifold 16.
[0043] The exhaust pipe 17 is connected with a TMP (Turbo Molecular
Pump) and a DP (Dry Pump) (both are not shown). These pumps
evacuate and depressurize the inside of the chamber 11. To
elaborate, the DP depressurizes the inside of the chamber 11 to an
intermediate vacuum state (e.g., about 1.3.times.10 Pa (0.1 Torr)
or less) from an atmospheric pressure. Further, in cooperation with
the DP, the TMP further depressurizes the inside of the chamber 11
to a high vacuum state (e.g., about 1.3.times.10.sup.-3 Pa
(1.0.times.10.sup.-5 Torr) or less) lower than the intermediate
pressure state. The internal pressure of the chamber 11 is
controlled by an APC valve (not shown).
[0044] The susceptor 12 within the chamber 11 is connected with a
first high frequency power supply 18 via a first matching unit 19
and also connected with a second high frequency power supply 20 via
a second matching unit 21. The first high frequency power supply 18
is configured to apply a high frequency power of a relatively low
frequency for ion attraction (e.g., about 2 MHz) to the susceptor
12, and the second high frequency power supply 20 is configured to
apply a high frequency power of a relatively high frequency for
plasma generation (e.g., about 60 MHz) to the susceptor 12. In this
configuration, the susceptor 12 may serve as an electrode. Further,
the first and second matching units 19 and 21 may reduce reflection
of the high frequency powers from the susceptor 12, thus improving
the efficiency of applying the high frequency powers to the
susceptor 12.
[0045] A step-shaped portion is formed at a periphery of a top
portion of the susceptor 12 such that a central portion of the
susceptor 12 protrudes upward. Provided at a top end of the central
portion of the susceptor 12 is an electrostatic chuck 23 made of
ceramics and having an electrostatic electrode plate 22 therein.
The electrostatic electrode plate 22 is connected with a DC power
supply 24. If a positive DC voltage is applied to the electrostatic
electrode plate 22, a negative potential would be generated in a
surface (hereinafter, referred to as a "rear surface") of the wafer
W facing the electrostatic chuck 23. Therefore, a potential
difference is generated between the electrostatic electrode plate
22 and the rear surface of the wafer W. As a result, the wafer W
can be attracted to and held on the electrostatic chuck 23 by a
Coulomb force or a Johnsen-Rahbek force generated by the potential
difference.
[0046] Further, the susceptor 12 has therein a cooling device (not
shown) of a coolant path. In the present embodiment, the cooling
device is configured to absorb, via the susceptor 12, heat of the
wafer W of which temperature increases as a result of its contact
with the plasma. Therefore, the temperature of the wafer W is
prevented from increasing over a desired level.
[0047] The susceptor may be made of a conductor such as aluminum in
consideration of its heat transfer efficiency or its function as an
electrode. Further, in order to prevent the conductor from being
exposed to the processing chamber 15 in which the plasma is
generated, disposed at the side surface of the susceptor 12 is a
side protection member 26 made of a dielectric material such as,
but not limited to, quartz (SiO.sub.2).
[0048] A focus ring 25 is placed on the step-shaped portion
(mounting surface) of the susceptor 12 and the side protection
member 26 so as to surround the wafer W attracted to and held on
the electrostatic chuck 23. The focus ring 25 may be a dual focus
ring including an inner focus ring 25a surrounding the wafer W and
an outer focus ring 25b surrounding the inner focus ring 25a. The
inner focus ring 25a and the outer focus ring 25b may be made of,
but not limited to, silicon (Si) or silicon carbide (SiC). That is,
since the focus ring 25 is made of a semiconductor, a distribution
range of the plasma can be expanded to above the focus ring 25 as
well as above the wafer W. Thus, a plasma density in a region above
a periphery portion of the wafer W can be maintained at the
substantially same level as a plasma density in a region above a
central portion of the wafer W. Accordingly, it is possible to
uniformly perform the plasma etching process on the entire surface
of the wafer W.
[0049] The inner focus ring 25a is mainly mounted on the
step-shaped portion of the susceptor 12. Meanwhile the outer focus
ring 25b is mainly mounted on the side protection member 26.
Further, a heat transfer sheet 34 made of, e.g., silicon rubber
having heat transfer property is provided between the inner focus
ring 25a and the susceptor 12, as shown in FIG. 2(A) to be
described later. Heat of the inner focus ring 25a, of which
temperature increases as a result of the contact with the plasma,
is transferred to the susceptor 12 via the heat transfer sheet 34
and then absorbed by the cooling device of the susceptor 12.
Meanwhile, since no element is provided between the outer focus
ring 25b and the side protection member 26, if the inner space of
the processing chamber 15 is depressurized, a heat insulating
vacuum layer is formed between the outer focus ring 25b and the
side protection member 26. Accordingly, heat of the outer focus
ring 25b, of which temperature increases as a result of the contact
with the plasma, is not transferred to the side protection member
26. As a result, the outer focus ring 25b is not cooled, and, thus,
the temperature of the outer focus ring 25b is maintained at a high
level. Accordingly, the temperature of the inner focus ring 25a can
be maintained at a desired low level, while the temperature of the
outer focus ring 25b can be maintained at the high level.
[0050] A shower head 27 is provided at a ceiling of the chamber 11
so as to face the susceptor 12. The shower head 27 includes an
upper electrode plate 28, a cooling plate 29 that supports the
upper electrode plate 28 in a detachable manner, and a cover 30
that covers the cooling plate 29. The upper electrode plate 28 is a
circular plate-shaped member having a multiple number of gas holes
31 formed in a thickness direction thereof. A buffer room 32 is
provided within the cooling plate 29, and a processing gas inlet
pipe 33 is connected to the buffer room 32.
[0051] In the substrate processing apparatus, a processing gas
supplied into the buffer room 32 via the processing gas inlet pipe
33 is introduced into the inner space of the processing chamber 15
through the gas holes 31. The introduced processing gas is excited
into plasma by the high frequency power for plasma generation
applied into the inner space of the processing chamber 15 from the
second high frequency power supply 20 via the susceptor 12. Ions in
the plasma are attracted toward the wafer W by the high frequency
power for ion attraction applied to the susceptor 12 from the first
high frequency power supply 18, and, thus, the plasma etching
process is performed on the wafer W.
[0052] While the plasma etching process is being performed on the
wafer W, reaction products generated as a result of a reaction
between an etching target layer of the wafer W and the plasma float
in the inner space of the processing chamber 15 and adhere to parts
of the processing chamber 15 as deposits. Especially, the deposits
tend to adhere to a member having a lower temperature in a gap
between two members of which temperatures are greatly different.
Accordingly, in a gap between the inner focus ring 25a and the
outer focus ring 25b, the deposits may adhere to the inner focus
ring 25a. Since the gap between the inner focus ring 25a and the
outer focus ring 25b is narrow and has a labyrinth structure, it
may be difficult to remove the deposits adhering to the inner focus
ring 25a.
[0053] In order to solve this problem, in accordance with the first
embodiment, a member made of quartz is disposed in the gap between
the inner focus ring 25a and the outer focus ring 25b.
[0054] FIG. 2 provides enlarged cross sectional views illustrating
schematic configurations of a focus ring in the substrate
processing apparatus of FIG. 1. FIG. 2(A) shows a focus ring in
accordance with the first embodiment of the present disclosure;
FIG. 2(B), a first modification example of the focus ring in
accordance with the first embodiment; FIG. 2(C), a second
modification example of the focus ring in accordance with the first
embodiment; FIG. 2(D), a third modification example of the focus
ring in accordance with the first embodiment; FIG. 2(E), a fourth
modification example of the focus ring in accordance with the first
embodiment; and FIG. 2(F), a fifth modification example of the
focus ring in accordance with the first embodiment.
[0055] Referring to FIG. 2(A), a focus ring 25 has a block member
25c (quartz member) made of quartz and disposed in a gap between
the inner focus ring 25a and the outer focus ring 25b (hereinafter,
referred to as a "first gap").
[0056] When a plasma etching process is performed in the substrate
processing apparatus 10, if plasma, especially, radicals enter the
first gap to come into contact with the block member 25c, the
radicals chemically react with the quartz to generate oxygen
radicals from the block member 25c. If reaction products adhere to
the inner focus ring 25a as deposits in the first gap, the oxygen
radicals immediately make a chemical reaction with the deposits, so
that the deposits are decomposed to be removed. Accordingly, it is
possible to prevent the deposits from adhering to the inner focus
ring 25a in the first gap.
[0057] It is possible to prevent the deposits from adhering to the
inner focus ring 25a only if the oxygen radicals are generated in
the first gap. Thus, there will be no specific limit in the shape
or the size of the block member 25c as long as the block member 25c
is provided in the first gap. Accordingly, the block member 25c may
have various cross sectional shapes, such as a downwardly
protruding cross sectional shape (FIG. 2(B)), an upwardly
protruding cross sectional shape (FIG. 2(C)), a rectangular cross
sectional shape (FIG. 2(D)), and so forth. In any case, however, it
may be desirable that a part of the block member 25c is exposed to
the inner space of the processing chamber 15. In this way, the
block member 25c can be effectively contacted with the plasma, and,
thus, the oxygen radicals can be sufficiently generated from the
block member 25c. Alternatively, if the block member 25c can make a
contact with the plasma that enters the first gap, the block member
25c may not be directly exposed to the inner space of the
processing chamber 15 (FIG. 2(E)).
[0058] Moreover, the block member 25c may be extended to be also
placed between a bottom surface of the inner focus ring 25a and the
step-shaped portion of the susceptor 12 (FIG. 2(F)). By providing
the block member 25c in this way, it is possible to prevent
reaction products as a source of deposits from entering a gap
between the bottom surface of the inner focus ring 25a and the
step-shaped portion of the susceptor 12. Moreover, since the block
member 25c also generates oxygen radicals between the bottom
surface of the inner focus ring 25a and the step-shaped portion of
the susceptor 12, decomposition and removal of the deposits by the
oxygen radicals can be facilitated in the gap between the bottom
surface of the inner focus ring 25a and the step-shaped portion of
the susceptor 12. In addition, in this configuration, heat transfer
sheets 34a and 34b may be disposed between the step-shaped portion
of the susceptor 12 and the block member 25c and between the block
member 25c and the inner focus ring 25a, respectively.
[0059] Since the block member 25c is made of quartz, silicon
radicals as well as the oxygen radicals may be generated when the
block member 25c makes a chemical reaction with the plasma. Since
the silicon radicals may combine with a silicon simple substance or
an oxygen gas to adhere to members within the processing chamber 15
as silicon oxide, it may be desirable to introduce a carbon
fluoride (CF)-based processing gas into the inner space of the
processing chamber 15. As a result, since plasma generated from the
carbon fluoride-based processing gas decomposes silicon or silicon
carbide, it is possible to prevent the silicon or silicon carbide
from adhering to the members.
[0060] Now, a substrate processing apparatus in accordance with a
second embodiment of the present disclosure will be described.
[0061] Since a configuration and an operation of the second
embodiment are basically the same as those of the above-described
first embodiment, redundant description will be omitted and only
distinctive configuration and operation will be elaborated.
[0062] In the substrate processing apparatus 10 of FIG. 1, a gap
having a certain width is formed between the side surface of the
susceptor 12 and an inner side surface of an inner focus ring 25a
in order to easily attach and detach a focus ring 25 to/from the
susceptor 12. Since the susceptor 12 is directly cooled by the
cooling device embedded therein, a temperature of the susceptor 12
becomes considerably lower than a temperature of the inner focus
ring 25a. That is, there may be a great temperature difference
between both sides of a gap between the side surface of the
susceptor 12 and the inner side surface of the inner focus ring 25a
(hereinafter, referred to as a "second gap"). As a result, in the
second gap, deposits may adhere to the susceptor 12.
[0063] In order to solve this problem, in accordance with the
second embodiment, a member made of quartz is disposed in the
second gap.
[0064] FIG. 3 provides enlarged cross sectional views schematically
illustrating configurations of a focus ring included in the
substrate processing apparatus in accordance with the second
embodiment. FIG. 3(A) shows a focus ring in accordance with the
second embodiment of the present disclosure; FIG. 3(B), a first
modification example of the focus ring in accordance with the
second embodiment; FIG. 3(C), a second modification example of the
focus ring in accordance with the second embodiment; and FIG. 3(D),
a third modification example of the focus ring in accordance with
the second embodiment.
[0065] Referring to FIG. 3(A), the focus ring 25 includes a block
member 25d (quartz member) made of quartz and disposed in the
second gap.
[0066] When a plasma etching process is performed in the substrate
processing apparatus 10, if plasma, especially, radicals enter the
second gap to come into contact with the block member 25d, oxygen
radicals are generated from the block member 25d. The oxygen
radicals make a chemical reaction with deposits in the second gap,
so that the deposits are decomposed and removed. Accordingly, it is
possible to prevent the deposits from adhering to the susceptor 12
in the second gap. Here, there exists a great temperature
difference between both sides of the second gap.
[0067] It is possible to prevent the deposits from adhering to the
susceptor 12 only if the oxygen radicals are generated in the
second gap. Thus, there will be no specific limit in the shape or
the size of the block member 25d as long as the block member 25d is
provided in the second gap. Moreover, the block member 25d may also
be provided between the bottom surface of the inner focus ring 25a
and the step-shaped portion of the susceptor 12 (FIG. 3(B)). By
providing the block member 25d in this way, it is possible to
prevent reaction products as a source of deposits from entering the
gap between the bottom surface of the inner focus ring 25a and the
step-shaped portion of the susceptor 12. Moreover, since the block
member 25d also generates oxygen radicals between the bottom
surface of the inner focus ring 25a and the step-shaped portion of
the susceptor 12, decomposition and removal of the deposits by the
oxygen radicals can be facilitated in the gap between the bottom
surface of the inner focus ring 25a and the step-shaped portion of
the susceptor 12. In this case, the heat transfer sheets 34a and
34b may be disposed between the step-shaped portion of the
susceptor 12 and a bottom surface of the block member 25d and
between a top surface of the block member 25d and the inner focus
ring 25a, respectively.
[0068] Moreover, the block member 25d may be extended to be placed
in the first gap (FIG. 3(B)). With this configuration, it may be
possible to prevent deposits from adhering to members in both the
first gap and the second gap.
[0069] In addition, the focus ring 25 may have a block member 25c
as described in the first embodiment as well as the block member
25d (FIG. 3(C)). Further, the block member 25d may also be provided
between a bottom surface of the outer focus ring 25b and a side
protection member 26 as well as between the bottom surface of the
inner focus ring 25a and the step-shaped portion of the susceptor
12 (FIG. 3(D)).
[0070] Subsequently, a substrate processing apparatus in accordance
with a third embodiment will be described.
[0071] Since a configuration and an operation of the third
embodiment are basically the same as those of the above-described
first embodiment, redundant description thereof will be omitted and
only distinctive configuration and operation will be
elaborated.
[0072] FIG. 4 provides enlarged cross sectional views schematically
illustrating configurations of a focus ring in the substrate
processing apparatus in accordance with the third embodiment. FIG.
4(A) illustrates a focus ring in accordance with third second
embodiment, and FIG. 4(B) illustrates a first modification example
of the focus ring in accordance with the third embodiment.
[0073] Referring to FIG. 4(A), the substrate processing apparatus
10 includes a gas supply port 35 (gas supply device) that is opened
at the step-shaped portion of the susceptor 12 and faces the bottom
surface of the inner focus ring 25a. The gas supply port 35
supplies a certain gas, e.g., an oxygen gas toward the bottom
surface of the inner focus ring 25a when a plasma etching process
or a cleaning process using plasma such as WLDC (Wafer Less Dry
Cleaning) process is performed in the substrate processing
apparatus 10. The supplied oxygen gas (indicated by arrows in FIG.
4) flows between the step-shaped portion of the susceptor 12 and
the bottom surface of the inner focus ring 25a and is supplied into
at least one of the first and second gaps.
[0074] The oxygen gas supplied into the first or the second gap
comes into contact with plasma that has entered the first or the
second gap, so that oxygen radicals are generated. These oxygen
radicals make a chemical reaction with deposits in the first or the
second gap, and, thus, the deposits are decomposed to be removed.
As a result, in the first or second gap where there exists a great
temperature difference, it is possible to prevent the deposits from
adhering to the susceptor 12 or the inner focus ring 25a. Moreover,
the oxygen gas supplied into the first or the second gap pushes out
reaction products, which have entered the first or the second gap
and would become a source of the deposits, into the inner space of
the processing chamber 15. Accordingly, it is possible to further
effectively prevent adhesion of the deposits in the first or the
second gap.
[0075] In the above-described third embodiment, although the gas
supply port 35 is formed in the step-shaped portion of the
susceptor 12, the position of the gas supply port 35 may not be
limited to the step-shaped portion of the susceptor 12 as long as
the gas from the gas supply port 35 can be supplied into the first
or the second gap. By way of non-limiting example, the gas supply
port 35 may be formed between the susceptor 12 and the side
protection member 26 (FIG. 4(B)), or may be formed in the side
protection member 26 (not shown).
[0076] Further, the gas supplied from the gas supply port 35 may
not be limited to the oxygen gas. By way of non-limiting example,
an inert gas such as a rare gas, a nitrogen gas, or a processing
gas may be supplied instead. The inert gas serves to push out the
reaction products that have entered the first or the second gap.
Further, since the inert gas does not react with the plasma
introduced into the first or second gap, any new reaction products
are not produced. Accordingly, it is possible to more effectively
prevent adhesion of the deposits in the first or the second gap.
Likewise, the processing gas also serves to push out the reaction
products entering the first or the second gap. Further, even if the
processing gas is introduced into the inner space of the processing
chamber 15, it may not affect components of the plasma. Thus,
unintended plasma etching may not be performed on the wafer W.
[0077] In addition, if the oxygen gas or the processing gas is
introduced into the inner space of the processing chamber 15 when
these gases are supplied from the gas supply port 35, plasma
density or plasma distribution in the inner space of the processing
chamber 15 may be affected. In order to solve this problem, in the
substrate processing apparatus 10, it may be desirable to reduce an
amount of the oxygen gas or the processing gas supplied from a part
of a shower head 27 corresponding to the first or the second
gap.
[0078] Now, a substrate processing apparatus in accordance with a
fourth embodiment of the present disclosure will be explained.
[0079] Since a configuration and an operation of the fourth
embodiment are basically the same as those of the above-described
first embodiment, redundant description thereof will be omitted and
only distinctive configuration and operation will be
elaborated.
[0080] FIG. 5 is an enlarged cross sectional view schematically
illustrating a configuration of a focus ring in the substrate
processing apparatus in accordance with the fourth embodiment.
[0081] Referring to FIG. 5, an inner focus ring 25a has a thin
plate-shaped flange 25e (protrusion) on the side of the inner space
of the processing chamber 15. The flange 25e is exposed to the
inner space of the processing chamber 15 and protrudes so as to
cover all or a part of the outer focus ring 25b. A first gap is
formed between the flange 25e and a surface of the outer focus ring
25b facing the flange 25e. A thickness of the flange 25e may be set
to be in the range of, but not limited to, about 1.7 mm to about
2.0 mm.
[0082] Since the flange 25e is thin, heat capacity thereof is small
and a temperature thereof is increased higher than that of the
remaining part of the inner focus ring 25a by radiant heat from
plasma when a plasma etching process or a WLDC process is performed
in the substrate processing apparatus 10. As a result, in the first
gap, a temperature difference between the inner focus ring 25a and
the outer focus ring 25b can be reduced, so that it becomes
possible to prevent deposits from adhering to the inner focus ring
25a in the first gap. Moreover, even if deposits are attached to
the inner focus ring 25a in the first gap, the deposits may be
decomposed and removed by radiant heat from the flange 25e or the
outer focus ring 25b having high temperatures.
[0083] In accordance with the fourth embodiment, since the flange
25e is formed to cover all or a part of the outer focus ring 25b,
the first gap may have a labyrinth structure. As a result, it may
be difficult for reaction products as a source of deposits to enter
the first gap toward the side of the susceptor 12, and, thus,
adhesion of deposits in the first gap can be prevented.
[0084] Moreover, since a minimum thickness of the flange 25e is
e.g., about 1.7 mm, it can be possible to prevent the strength of
the flange 25e from being critically decreased, and to prevent the
flange 25e from being broken or damaged while the inner focus ring
25a is being replaced. Furthermore, since a maximum thickness of
the flange 25e is, e.g., about 2.0 mm, it can be prevented that the
heat capacity of the flange 25e increases beyond a certain level.
As a result, it is possible to effectively increase the temperature
of the flange 25e by the radiant heat from the plasma.
[0085] Although there has been described the present disclosure for
the respective embodiments, the present disclosure may not be
limited to the aforementioned embodiments.
[0086] Further, the above-described embodiments may be applicable
not only to the plasma processing apparatus 10 configured to
perform a plasma etching process on a wafer W for a semiconductor
device but also to a plasma processing apparatus configured to
process various types of substrates for use in a FPD (Flat Panel
Display) including a LCD (Liquid Crystal Display), a photo mask, a
CD substrate, a printed substrate, and the like by using
plasma.
[0087] In the above, there have been described embodiments capable
of preventing adhesion of deposits in the first or the second gap.
For example, however, if a large quantity of reaction products is
generated in the plasma etching process, it may be not possible to
completely prevent the adhesion of the deposits in the first or
second gap even in accordance with the above-described
embodiments.
[0088] Below, an example substrate processing apparatus capable of
removing deposits in the first or second gap will be elaborated.
Examples to be described below can be used together with any of the
above-described embodiments of the present disclosure.
[0089] FIG. 6 presents enlarged cross sectional views each
schematically illustrating a configuration in the vicinity of a
focus ring in a substrate processing apparatus capable of removing
attached deposits. FIG. 6(A) shows a first example and FIG. 6(B)
shows a second example.
[0090] Referring to FIG. 6(A), the side protection member 26 has a
protrusion 26a. The protrusion 26a is made of material capable of
transmitting a laser beam, e.g., quartz and is formed to upwardly
protrude toward a first gap. The protrusion 26a has a facing
surface 26b facing an inner focus ring 25a in a first gap. Further,
a first laser beam irradiation device (not shown) is provided below
the side protection member 26, and the first laser beam irradiation
device is configured to irradiate a laser beam 36 for heating the
focus ring toward the side protection member 26. By way of
non-limiting example, the laser beam 36 may have a wavelength equal
to or smaller than about 1100 nm.
[0091] The laser beam 36 irradiated to the side protection member
26 is reflected at respective inner surfaces of the side protection
member 26 repetitively, and then, finally irradiated to the outer
focus ring 25b from an upper portion of the side protection member
26. Since the outer focus ring 25b is made of silicon or silicon
carbide, the outer focus ring 25b can absorb the laser beam 36
having the wavelength equal to or smaller than about 1100 nm. As a
result, the outer focus ring 25b may be heated by the absorbed
laser beam 36. At this time, since the facing surface 26b of the
protrusion 26a faces the inner focus ring 25a in the first gap, a
part of the laser beam 36 is irradiated toward the inner focus ring
25a from the facing surface 26b. The part of the laser beam
irradiated to the inner focus ring 25a can be absorbed by the
deposits adhering to the inner focus ring 25a, so that a
temperature of the deposits is increased. As a result, it is
possible to easily decompose and remove the deposits, so that the
deposits adhering to the inner focus ring 25a having a lower
temperature in the first gap can be removed.
[0092] Further, if the temperature of the deposits is not
sufficiently increased because a light amount of a part of the
laser beam 36 for heating the focus ring irradiated to the inner
focus ring 25a is small, a laser beam different from the laser beam
36 for heating the focus ring, e.g., a laser beam capable of being
efficiently absorbed by the deposits may also be irradiated to the
side protection member 26, and a part of this another laser beam
may be irradiated toward the inner focus ring 25a from the facing
surface 26b. In this way, the temperature of the deposits can be
increased sufficiently and efficiently.
[0093] Moreover, in case that a laser beam cannot be directly
irradiated to the first gap, for example, in case that the first
gap has a labyrinth structure, a laser beam guide member 37 (laser
beam transmitting member) may be provided between a susceptor 12
and the side protection member 26 so as to face the first gap, as
illustrated in FIG. 6(B). The laser beam guide member 37 is made of
quartz and provided as a separate member from the side protection
member 26. Further, a second laser beam irradiation device (not
shown) may be provided under the laser beam guide member 37. This
second laser beam irradiation device may be configured to irradiate
a laser beam 38 having a wavelength larger than, e.g., about 1100
nm toward the laser beam guide member 37.
[0094] The laser beam 38 irradiated to the laser beam guide member
37 is repetitively reflected at respective inner surfaces of the
laser beam guide member 37 while it passes through the laser beam
guide member 37, and then, finally irradiated to the first gap from
an upper portion of the laser beam guide member 37. Here, since the
first gap has a labyrinth structure, a part of the inner focus ring
25a or a part of the outer focus ring 25b may be located on a
travel path of the laser beam 38. Since a laser beam having a
wavelength larger than about 1100 nm may pass through the silicon
or silicon carbide, the laser beam 38 may reach the first gap
through the part of the inner focus ring 25a or the part of the
outer focus ring 25b. Then, the laser beam 38 may be absorbed by
the deposits in the first gap, so that a temperature of the deposit
is increased. As a result, the deposits in the first gap can be
removed.
[0095] Moreover, in case that a component or a member for absorbing
the laser beam is not provided between the first gap and the second
laser beam irradiation device, the second laser beam irradiation
device may be provided at a vicinity of a sidewall of the chamber
11 or at a vicinity of a cover at the top of the chamber 11 as well
as provided below the laser beam guide member 37. In this case, it
may be desirable to dispose the second laser beam irradiation
device to face the first gap.
[0096] FIG. 7 provides enlarged cross sectional views each
schematically illustrating a configuration in the vicinity of a
focus ring in a substrate processing apparatus capable of removing
attached deposits. FIG. 7(A) shows a third example, and FIG. 7(B)
shows a fourth example.
[0097] As depicted in FIG. 7(A), the substrate processing apparatus
10 further includes a pusher pin 39 configured to be protruded from
the step-shaped portion of the susceptor 12. When the pusher pin 39
protrudes upwardly, the pusher pin 39 lifts up the inner focus ring
25a away from the outer focus ring 25b. Typically, if deposits come
into contact with plasma, the deposits make a chemical reaction
with the plasma, especially, radicals therein, so that the deposits
are decomposed to be removed. Here, since the inner focus ring 25a
lifted up by the pusher pin 39 is exposed to the plasma within the
inner space of the processing chamber 15, deposits adhering to the
inner focus ring 25a is easily decomposed and removed. As a result,
it may be possible to remove deposits adhering to the inner focus
ring 25a having a lower temperature in the first gap
[0098] Moreover, referring to FIG. 7(B), the substrate processing
apparatus 10 further includes a pusher pin 40 configured to be
protruded from the top surface of the side protection member 26.
When the pusher pin 40 protrudes upwardly, the pusher pin 40 lifts
up the outer focus ring 25b away from the inner focus ring 25b. In
this example, since the outer focus ring 25b is spaced apart from
the inner focus ring 25a, deposits adhering to the inner focus ring
25a are exposed to plasma within the inner space of the processing
chamber 15. Accordingly, the deposits adhering to the inner focus
ring 25a of the lower temperature can be easily decomposed and
removed. As a result, it may be possible to remove the deposits
adhering to the inner focus ring 25a in the first gap.
[0099] The removal of the deposits in the third or fourth example
may be performed when a WLDC process is performed in the substrate
processing apparatus 10. Further, in the third or fourth example,
since the pusher pins are used as members for moving the inner
focus ring 25a or the outer focus ring 25b, complication of the
structure of the substrate processing apparatus 10 can be
avoided.
[0100] FIG. 8 provides enlarged cross sectional views each
schematically illustrating a configuration in the vicinity of a
focus ring in a substrate processing apparatus capable of removing
attached deposits. FIG. 8(A) depicts a fifth example; FIG. 8(B), a
sixth example; FIG. 8(C), a seventh example; and FIG. 8(D), an
eighth example.
[0101] Referring to FIG. 8(A), the substrate processing apparatus
10 further includes a grounding member 41 made of a semiconductor
or a conductor (e.g., silicon). The grounding member 41 is provided
under the outer focus ring 25b at an outside of the side protection
member 26. An electric potential of the grounding member 41 is
maintained as a ground potential.
[0102] In the present example, since the grounding member 41 is
provided near the outer focus ring 25b, an electric potential of
the outer focus ring 25b may also become close to the ground
potential. Meanwhile, since a negative bias potential is generated
in the susceptor 12 or the inner focus ring 25a, the electric
potential of the outer focus ring 25b becomes relatively higher, so
that electrons can be easily attracted to the outer focus ring 25b.
As a result, the thickness of a sheath corresponding to the outer
focus ring 25b may be increased, and plasma in the inner space of
the processing chamber 15 can be concentrated on a position
corresponding to the inner focus ring 25a as compared to a position
corresponding to the outer focus ring 25b. Accordingly, a plasma
density corresponding to the first gap or the second gap can be
increased, so that plasma reaching the first or second gap can also
be increased. Consequently, deposits in the first or second gap by
the plasma can be easily decomposed, so that it becomes possible to
remove deposits adhering to the inner focus ring 25a having a lower
temperature in the first gap and, also, deposits adhering to the
susceptor 12 having an even lower temperature in the second
gap.
[0103] Referring to FIG. 8(B), the substrate processing apparatus
10 further includes a ground electrode 42 having a ground
potential. The ground electrode 42 is provided within the side
protection member 26 to be located near a focus ring 25.
[0104] In this example, since the ground electrode 42 is provided
near the outer focus ring 25b, an electric potential of the outer
focus ring 25b may also become close to the ground potential. As a
result, the plasma in the inner space of the processing chamber 15
can be concentrated on a position corresponding to the inner focus
ring 25a as compared to a position corresponding to the outer focus
ring 25b. Accordingly, a plasma density corresponding to the first
gap or the second gap can be increased, so that it becomes possible
to remove deposits adhering to the inner focus ring 25a having the
lower temperature in the first gap and, also, deposits adhering to
the susceptor 12 having the even lower temperature in the second
gap.
[0105] Referring to FIG. 8(C), the substrate processing apparatus
10 further includes a positive potential electrode provided within
the side protection member 26 to be located near the outer focus
ring 25b. A positive voltage is applied to the positive potential
electrode 43.
[0106] In the present example, since the positive potential
electrode 43 is disposed near the outer focus ring 25b, the outer
focus ring 25b may also have a positive potential. As a result, the
plasma in the inner space of the processing chamber 15 can be
further concentrated on a position corresponding to the inner focus
ring 25a as compared to a position corresponding to the outer focus
ring 25b. Accordingly, a plasma density corresponding to the first
gap or the second gap can be increased, so that it becomes possible
to remove deposits adhering to the inner focus ring 25a having the
lower temperature in the first gap and, also, deposits adhering to
the susceptor 12 having the even lower temperature in the second
gap.
[0107] Referring to FIG. 8(D), the substrate processing apparatus
10 further includes an electromagnet 44 provided in the vicinity of
the first gap to be located below the focus ring 25.
[0108] In the present example, the electromagnet 44 may serve to
generate a magnetic field around the first gap, thus concentrating
the plasma in the inner space of the processing chamber 15 on a
position corresponding to the inner focus ring 25a as compared to a
position corresponding to the outer focus ring 25b. Accordingly, a
plasma density corresponding to the first gap or the second gap can
be increased, so that it becomes possible to remove deposits
adhering to the inner focus ring 25a having the lower temperature
in the first gap and, also, deposits adhering to the susceptor 12
having the even lower temperature in the second gap.
* * * * *