U.S. patent application number 12/597602 was filed with the patent office on 2010-08-26 for etching method and etching apparatus.
This patent application is currently assigned to ULVAC, INC.. Invention is credited to Mitsuhiro Endou, Yutaka Kokaze, Toshiya Miyazaki, Toshiyuki Nakamura, Koukou Suu, Masahisa Ueda.
Application Number | 20100213170 12/597602 |
Document ID | / |
Family ID | 40185562 |
Filed Date | 2010-08-26 |
United States Patent
Application |
20100213170 |
Kind Code |
A1 |
Kokaze; Yutaka ; et
al. |
August 26, 2010 |
ETCHING METHOD AND ETCHING APPARATUS
Abstract
An etching method which uses an apparatus having a chamber in
which an etching gas is excited by plasma; a table arranged in the
chamber which heats a substrate mounted thereon; and a frame member
which includes etching-endurable material which is arranged around
the table, and which has an upper surface arranged at a position
lower than an upper surface of the table, the etching method
including: arranging the substrate on the upper surface of the
table such that a peripheral part of the substrate projects above
the table; and arranging the substrate such that a ratio of a
height from the upper surface of the frame member to a bottom
surface of the substrate and a projecting length from a side
surface of the table to an outer circumference of the substrate is
1.5 or more
Inventors: |
Kokaze; Yutaka; (Susono-shi,
JP) ; Endou; Mitsuhiro; (Susono-shi, JP) ;
Ueda; Masahisa; (Susono-shi, JP) ; Suu; Koukou;
(Susono-shi, JP) ; Miyazaki; Toshiya; (Susono-shi,
JP) ; Nakamura; Toshiyuki; (Susono-shi, JP) |
Correspondence
Address: |
GROSSMAN, TUCKER, PERREAULT & PFLEGER, PLLC
55 SOUTH COMMERICAL STREET
MANCHESTER
NH
03101
US
|
Assignee: |
ULVAC, INC.
Chigasaki-shi
JP
|
Family ID: |
40185562 |
Appl. No.: |
12/597602 |
Filed: |
June 19, 2008 |
PCT Filed: |
June 19, 2008 |
PCT NO: |
PCT/JP2008/061215 |
371 Date: |
March 8, 2010 |
Current U.S.
Class: |
216/67 ;
156/345.52 |
Current CPC
Class: |
H01J 2237/022 20130101;
H01J 2237/2001 20130101; H01L 21/67069 20130101; H01L 27/1159
20130101; G11C 11/22 20130101; H01J 37/3266 20130101; H01L 27/11507
20130101; H01L 21/68735 20130101; H01J 37/32568 20130101; H01L
21/31122 20130101; H01J 37/32642 20130101; H01L 21/32136 20130101;
C23F 4/00 20130101; H01J 37/321 20130101 |
Class at
Publication: |
216/67 ;
156/345.52 |
International
Class: |
C23F 4/00 20060101
C23F004/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 22, 2007 |
JP |
2007-165043 |
Claims
1. An etching method which uses an apparatus having: a chamber in
which an etching gas is excited by a plasma; a table arranged in
the chamber which heats a subject substrate mounted thereon; and a
frame member which includes an etching-endurable material arranged
around the table, and which has an upper surface arranged at a
position lower than an upper surface of the table, the etching
method comprising: arranging the subject substrate on the upper
surface of the table such that a peripheral part of the subject
substrate projects above the table; and arranging the subject
substrate such that a ratio H/G of a height from the upper surface
of the frame member to a bottom surface of the subject substrate
and a projecting length from a side surface of the table to an
outer circumference of the subject substrate is 1.5 or more.
2. The etching method according to claim 1, wherein the table
includes a material having aluminum nitride as a major
component.
3. The etching method according to claim 1, further comprising:
arranging the subject substrate such that the height from the upper
surface of the frame member to the bottom surface of the subject
substrate becomes 1.0mm or more.
4. The etching method according to claim 1, further comprising:
etching a noble metal coating and a ferroelectric film formed on
the subject substrate by the etching gas.
5. The etching method according to claim 4, wherein the noble metal
coating and the ferroelectric film configure a storage device of a
ferroelectric memory.
6. The etching method according to claim 4, wherein the noble metal
coating includes at least one of Pt (platinum), Ir (iridium),
IrO.sub.2 (iridium oxide), and SrRuO.sub.3 (strontium ruthenium
oxide).
7. The etching method according to claim 4, wherein the
ferroelectric film includes at least one of PZT (Pb(Zr,Ti)O.sub.3,
lead zirconate titanate), SBT (SrBi.sub.2Ta.sub.2O.sub.9; strontium
bismuth tantalate), BTO (Bi.sub.4Ti.sub.3O.sub.12; bismuth
titanate), and BLT ((Bi,La).sub.4Ti.sub.3O.sub.12; bismuth
lanthanum titanate).
8. An etching apparatus comprising: a chamber in which an etching
gas is excited by plasma; a table arranged in the chamber, the
table heating a subject substrate which is mounted on the table;
and a frame member arranged around the table which includes
etching-endurable material, wherein: the frame member has an upper
surface which is arranged at a position lower than an upper surface
of the table; and an external form of the table is configured such
that, above the frame member, a peripheral part of the subject
substrate arranged on the upper surface of the table projects, and
is configured such that a ratio H/G of a height G from the upper
surface of the frame member to a bottom surface of the subject
substrate and a projecting length H from a side surface of the
table to an outer circumference of the subject substrate is 1.5 or
more.
Description
TECHNICAL FIELD OF THE INVENTION
[0001] The present invention relates to an etching method and an
etching apparatus.
[0002] Priority is claimed on Japanese Patent Application No.
2007-165043, the contents of which are incorporated herein by
reference.
BACKGROUND ART
[0003] Plasma etching apparatuses are widely employed.
[0004] FIG. 1 illustrates a schematic diagram of an etching
apparatus. The etching apparatus 1 includes a chamber 10 in which
an etching gas is excited by plasma, and a table 52 on which a
substrate 90 is mounted. The table 52 is provided in the chamber
10. The table 52 works as a hotplate for heating the substrate 90,
and consists of materials with a high degree of heat conductivity
such as aluminum nitride. The table 52 is embedded with an
electrode 41 which applies a bias to the substrate 90. Around the
table 52, a ring-shaped plate 53, which consists of
etching-endurable material such as quartz, is provided.
[0005] FIG. 3 is an enlarged illustration of a portion P in FIG. 1.
The plate 53 has an upper surface which is arranged at a position
lower than an upper surface of a center portion 52a of the table 52
(for example, refer to Patent Document 1 and Patent Document 2).
According to this arrangement, even if etching products 110 with
conductive properties are deposited on the upper surface of the
plate 53, an occurrence of electrical discharge between the etching
products 110 and the substrate 90 can be prevented. The outer
diameter of the table 52 is set such that, above the plate 53, a
peripheral part of the substrate 90 mounted on the upper surface of
the table 52 projects from the table. With this configuration, the
upper surface of the table 52 is prevented from being exposed by
plasma. [0006] Patent Document 1: Japanese Unexamined Patent
Application, First Publication No. 2006-339391 [0007] Patent
Document 2: Japanese Unexamined Patent Application, First
Publication No. 2005-136165
DISCLOSURE OF THE INVENTION
Problem To Be Solved By the Invention
[0008] In the etching apparatus 1 described above, the upper
surface of the plate 53 is arranged at a position lower than the
upper surface of the table 52; thus, a side surface of the table 52
is exposed. As a result, an etching gas excited by plasma flows
into a gap formed between the plate 53 and the substrate 90, and
the gas acts on the side surface of the table 52. Then, the side
surface of the table 52 undergoes a generation of particles,
thereby contaminating the substrate 90. In particular, in a case
that the substrate 90 is heated at a high temperature of
400.degree. C. or more, aluminum nitride which has a high degree of
heat conductivity may be employed for the table 52, but
unfortunately, the aluminum nitride is a material which easily
undergoes generation of particles.
[0009] The present invention is made in view of the aforementioned
circumstances, and an object thereof is to provide an etching
method and an etching apparatus that can prevent a subject
substrate from being contaminated by particles.
Means for Solving the Problem
[0010] In order to achieve the above-described object, the present
invention employs the following.
[0011] That is, an etching method of the present invention uses an
apparatus including a chamber in which an etching gas is excited by
plasma; a table arranged in the chamber which heats a subject
substrate mounted thereon, and a frame member which includes
etching-endurable material, which is arranged around the table, and
which has an upper surface arranged at a position lower than an
upper surface of the table, the etching method including: arranging
the subject substrate on the upper surface of the table such that a
peripheral part of the subject substrate projects above the table;
and arranging the subject substrate such that a ratio H/G of a
height from the upper surface of the frame member to a bottom
surface of the subject substrate and a projecting length from a
side surface of the table to an outer circumference of the subject
substrate is 1.5 or more
[0012] According to this etching method, the etching gas excited by
plasma hardly flows into the gap formed between the frame member
and the subject substrate. Therefore, generation of particles
caused by the etching gas which acts on the side surface of the
table can be suppressed. Accordingly, the subject substrate can be
prevented from contamination due to the particles.
[0013] The table may include a material having aluminum nitride as
a major component.
[0014] Aluminum nitride has a high degree of heat conductivity and
is desired to be used for heating the subject substrate, but easily
undergoes a generation of particles. However, according to the
etching method of the present invention, the generation of
particles due to the etching gas which acts on the side surface of
the table can be suppressed. Therefore, even if the table includes
a material having aluminum nitride as a major component, generation
of particles may be suppressed and the subject substrate can be
prevented from contamination.
[0015] The subject substrate may be arranged such that the height
defined from the upper surface of the frame member and the bottom
surface of the subject substrate becomes 1.0 mm or more.
[0016] Then, even if etching products having conductive properties
deposit on the upper surface of the frame member, an abnormal
electrical discharge between the etching products and the subject
substrate can be prevented.
[0017] A noble metal coating and a ferroelectric film formed on the
subject substrate may be etched by the etching gas.
[0018] The noble metal coating and the ferroelectric film may
configure a storage device such as a ferroelectric memory.
[0019] The noble metal coating may include at least one of Pt
(platinum), Ir (iridium), IrO.sub.2 (iridium oxide), and
SrRuO.sub.3 (strontium ruthenium oxide).
[0020] The ferroelectric film may include at least one of PZT
(Pb(Zr,Ti)O.sub.3, lead zirconate titanate), SBT
(SrBi.sub.2Ta.sub.2O.sub.9; strontium bismuth tantalate), BTO
(Bi.sub.4Ti.sub.3O.sub.12; bismuth titanate), and BLT
((Bi,La).sub.4Ti.sub.3O.sub.12; bismuth lanthanum titanate).
[0021] At the time of etching the noble metal coating and the
ferroelectric film, etching products having conductive properties
easily deposit on the upper surface of the frame member. Therefore,
in the present invention using the above configuration, an abnormal
electrical discharge between the etching products deposited on the
frame member and the subject substrate can be prevented.
[0022] The present invention provides an etching apparatus
including: a chamber in which an etching gas is excited by plasma;
a table arranged in the chamber, the table heating a subject
substrate which is mounted on the table; and a frame member
arranged around the table which includes etching-endurable
material, wherein: the frame member has an upper surface which is
arranged at a position lower than an upper surface of the table;
and an external form of the table is set such that, above the frame
member, a peripheral part of the subject substrate arranged on the
upper surface of the table projects, and is set such that a ratio
H/G becomes 1.5 or more. Here, "G" denotes the height defined from
the upper surface of the frame member to a bottom surface of the
subject substrate, and "H" denotes the projecting length defined
from a side surface of the table to an outer circumference of the
subject substrate.
[0023] According to this etching apparatus, the etching gas excited
by plasma hardly flows into the gap formed between the frame member
and the subject substrate. Therefore, generation of particles
caused by the etching gas which acts on the side surface of the
table can be suppressed. Accordingly, the subject substrate can be
prevented from contamination due to the particles.
Effect of the Invention
[0024] According to the present invention, an etching gas excited
by plasma hardly flows into a gap formed between a frame member and
a subject substrate, thus, it is possible to suppress generation of
particles due to the etching gas which acts on a side surface of
the table. Therefore, the subject substrate can be prevented from
being contaminated by particles.
BRIEF DESCRIPTION OF DRAWINGS
[0025] FIG. 1 is a longitudinal sectional view of an etching
apparatus according to an embodiment.
[0026] FIG. 2 is a plan view of the etching apparatus of the
embodiment.
[0027] FIG. 3 is an enlarged view of a portion P in FIG. 1.
[0028] FIG. 4 is a cross-sectional view of FeRAM.
[0029] FIG. 5 is a graph showing a relationship between a ratio H/G
and the number of particles.
TABLE-US-00001 Explanations of the Reference Symbols G gap (height)
H overhang amount (overhang length) 1 etching apparatus 10 chamber
52 table 53 plate (frame member) 100 FeRAM (ferroelectric memory)
102 lower side electrode (noble metal coating) 103 ferroelectric
layer (ferroelectric film) 104 upper side electrode (noble metal
coating)
BEST MODE FOR CARRYING OUT THE INVENTION
[0030] Hereinafter, an etching apparatus according to an embodiment
of the present invention will be described in detail with reference
to Drawings. It should be noted that in each of the figures
referred to in the following explanation, each member is suitably
modified such that the sizes there of are recognizable. In the
following embodiment, an explanation is made with a reactive ion
etching apparatus of inductively coupled type taken as an
example.
[0031] FIG. 1 is a longitudinal sectional view of an etching
apparatus 1 according to the embodiment. The etching apparatus 1
according to the embodiment includes a cylindrical chamber 10. The
chamber 10 has a ceiling 10a which is provided with an opening 10c.
The opening 10c is covered by a first quartz board 15 which is
provided on an outside of the ceiling 10a of the chamber 10. On the
first quartz board 15, a first electrode 31 is mounted. On the
first electrode 31, permanent magnets 32 are provided, and on the
permanent magnets 32, an antenna 33 is provided. The first
electrode 31 and the antenna 33 electrically connect to a first
high-frequency power source 34. The first electrode 31, the
permanent magnets 32, the antenna 33, and the first high-frequency
power source 34 configure a plasma generation unit 30.
[0032] FIG. 2 is a plan view of the etching apparatus. As described
above, the first electrode 31, the permanent magnets 32, and the
antenna 33 are arranged above the first quartz board 15. The first
electrode 31 includes a plurality of arms 31b which radially extend
from a center portion 31a. The center portion 31a of the first
electrode 31 is connected to a rotation device (not shown), and
thus the first electrode can be rotated in the circumferential
direction. The first electrode 31 is used for changing a cleaning
gas introduced into the chamber in a plasma state, and removing a
product adhered to the first quartz board 15.
[0033] As shown in FIG. 1, the chamber 10 has a bottom 10b which is
provided with an opening 10d. The opening 10d is covered by a base
member 44 which is provided on an inside of the bottom 10b of the
chamber 10. On the base member 44, a table 52 is mounted. The table
52 works as a hot plate for heating a substrate 90, and consists of
aluminum nitride (AlN) or the like with a high degree of heat
conductivity. The table 52 is embedded with a second electrode 41.
The second electrode 41 connects to a second high-frequency power
source 42, thereby configures a bias generation unit 40. Meanwhile,
in an inner surface of the bottom 10b of the chamber 10, a heating
device 51 is provided along the circumference of the base member
44. On the heating device 51, a substantially cylindrical
deposition preventing board 20 is mounted. An upper end portion of
the deposition preventing board 20 is in contact with the first
quartz board 15.
[0034] FIG. 3 is an enlarged view of a portion P in FIG. 1. As
shown in FIG. 3, the height of the table 52 is designed so that the
height of a rim 52b is lower than the height of a center portion
52a on which the substrate 90 is mounted. The second electrode 41
embedded in the center portion 52a of the table 52 has a function
of electrostatic chuck for holding the substrate 90. Meanwhile, on
the rim 52b of the table 52, a ring shaped plate (frame member) 53
is mounted. This plate 53 consists of etching-endurable material
such as quartz, and prevents the rim 52b of the table 52 from being
exposed to plasma. The upper surface of the plate 53 is arranged at
a position lower than the upper surface of the center portion 52a
of the table 52.
(Ferroelectric Memory)
[0035] As an example of a device fabricated on the substrate 90 by
using the etching apparatus 1, a ferroelectric memory such as FeRAM
(Ferroelectric Random Access Memory) may be fabricated.
[0036] FIG. 4 is a cross-sectional view of FeRAM. The FeRAM 100
includes a lower side electrode 102, ferroelectric layer 103, and
an upper side electrode 104 which are layered on a silicon
substrate 101.
[0037] The lower side electrode 102 and the upper side electrode
104 are each formed as a film. As materials of the lower side
electrode 102 and the upper side electrode 104, noble metals such
like Pt (platinum), Ir (iridium), IrO.sub.2 (iridium oxide), and
SrRuO.sub.3 (strontium ruthenium oxide) may be employed. As
materials of the ferroelectric layer 103, ferroelectrics such like
PZT (Pb(Zr,Ti)O.sub.3, lead zirconate titanate), SBT
(SrBi.sub.2Ta.sub.2O.sub.9; strontium bismuth tantalate), BTO
(Bi.sub.4Ti.sub.3O.sub.12; bismuth titanate), and BLT
((Bi,La).sub.4Ti.sub.3O.sub.12; bismuth lanthanum titanate) may be
employed.
[0038] In the FeRAM 100, the direction of spontaneous polarization
of the ferroelectric layer 103 can be modified by applying an
electric field to the ferroelectric layer 103 by creating an
electric potential difference between the lower side electrode 102
and the upper side electrode 104. Since the direction of the
spontaneous polarization can be maintained after discharging the
electric potential difference between the lower side electrode 102
and the upper side electrode 104, it is possible to store binary
data, 0 or 1, according to the direction of the spontaneous
polarization.
(Etching Method)
[0039] Hereinafter, with reference to FIG. 1, an etching method
using the etching apparatus 1 according to the embodiment will be
described as below.
[0040] Firstly, processes of mounting a substrate 90 on an upper
surface of a center portion 52a of a table 52, chucking the
substrate 90 by electrostatic chuck using a second electrode 41,
and heating the substrate 90 at 400.degree. C. or more by the table
52 are carried out. Next, processes of reducing a pressure in a
chamber 10 using a vacuum discharging system 70, and introducing an
etching gas into the chamber 10 from an etching gas application
device 60 are performed. For example, a halogen gas, a perfluoro
carbon gas or the like is introduced as the gas for etching a
ferroelectric layer or electrodes of FeRAM.
[0041] Next, a first high-frequency power source 34 is driven so as
to supply a high-frequency current to a first electrode 31 and an
antenna 33. Then, the etching gas in the chamber 10 is excited to a
plasma state. Further, a second high-frequency power source 42 is
driven so as to supply a high-frequency current to a second
electrode 41. Then, the etching gas excited to the plasma state
moves toward the substrate 90. As a result, the etching gas
collides with the ferroelectric layer or the electrodes provided on
the surface of the substrate 90 for etching. Here, the substrate 90
ejects etching products such as component materials of the
ferroelectric layer or the electrodes, and reactant materials
resulted from chemical reaction of these component materials with
the etching gas.
[0042] The etching product including the component materials of the
electrodes (i.e., noble metal) has conductive properties. This
etching product deposits on a surface of a deposition preventing
board 20, and on an upper surface of a plate 53. As shown in FIG.
3, the upper surface of the plate 53 is arranged at a position
lower than the upper surface of the center portion 52a of the table
52. Then, providing the substrate 90 on the center portion 52a of
the table 52, the substrate 90 and the plate 53 are separately
arranged with a gap therebetween. With this arrangement, even if
the etching products 110 having conductive properties deposit on
the upper surface of the plate 53, an occurrence of an abnormal
electrical discharge between the etching products 110 and the
substrate 90 can be prevented. More specifically, the occurrence of
a abnormal electrical discharge may be reliably prevented by
setting the distance of the gap (G) to 1 mm or more.
[0043] Meanwhile, since the upper surface of the plate 53 is
arranged at a position lower than the upper surface of the table
52, a side surface of the center portion 52a of the table 52 is
exposed. Therefore, the etching gas excited by plasma in a center
area of the chamber 10 flows into a gap 92 formed between the plate
53 and the substrate 90, and acts on the side surface of the table
52. In particular, since the second electrode 41 is arranged at a
position in the vicinity of the side surface of the table 52, ions
of the etching gas are attracted to the side surface of the table
52 by the second electrode 41. As a result, the side surface of the
table 52 undergoes a generation of particles. More specifically,
from the table 52 consisted of AIN, particles of AIN, AlO and the
like are generated. Then, the substrate 90 may be unfortunately
contaminated by these particles.
[0044] The etching gas which acts on the side surface of the table
52 is gas which has flowed into the gap 92 formed between the plate
53 and the substrate 90. Therefore, if it becomes difficult for the
etching gas to flow into the gap 92, the etching gas which acts on
the side surface of the table 52 can be reduced The following
methods may be suggested for making it difficult for the etching
gas to flow into the gap 92, that is, (1) a method of narrowing the
gap G (height) defined from the upper surface of the plate 53 to
the bottom surface of the substrate 90, and (2) a method of
extending the overhang amount (projecting length) H defined as the
length from the side surface of the table 52 to the outer
circumference of the substrate 90. However, if employing the method
(1) to narrow the gap G, the abnormal electrical discharge between
the etching products 110 deposited on the upper surface of the
plate 53 and the substrate 90 is likely to occur. If employing the
method (2) to extend the overhang amount H, it becomes tough for
bias application or heat application from the table 52 to reach
outer region of the substrate 90. As a result, it is difficult to
fabricate a device on the outer region of the substrate 90, and the
yield will be reduced.
[0045] For the above reasons, the present inventors carried out
experiments by variously changing the gap G and the overhang amount
H, and counting the number of particles deposited on the surface of
the substrate 90. More specifically, the experiments were carried
out by using substrates 90 having 8 inches of diameter, setting the
gap G to three patterns of 1.2 mm, 0.9 mm, and 0.3 mm, and setting
the overhang amount H to five patterns of 1 mm, 2 mm, 3 mm, 5 mm,
and 8.5 mm.
[0046] The experiments were carried out on 25 pieces of the
substrate 90 by etching electrode layers consisted of Ir. In these
experiments, mixed gases of HBr/O.sub.2/C.sub.4F.sub.8 were
introduced as an etching gas, the pressure was maintained at 0.5
Pa, the antenna power was set to 1400 W, and the bias power was set
to 1300 W.
[0047] Next, the experiments were carried out by mounting on the
table 52, the substrate 90 for which particles were to be counted,
and exposing the substrate 90 to plasma.
[0048] More specifically, Ar gas was introduced into the chamber
10, the pressure was maintained at 0.5 Pa, the antenna power was
set to 1400 W, and the bias power was set to 0 W.
[0049] Then, the surface of the substrate 90 was scanned by a
laser, and particles were counted based on the scattering light.
Based on the phenomenon that the intensity of the scattering light
varies depending on the particle size, the number of particles with
grain size of 0.2 .mu.m or more was counted. The result thereof is
shown in Table 1.
TABLE-US-00002 TABLE 1 overhang amount (H) 1 mm 2 mm 3 mm 5 mm 8.5
mm gap 1.2 mm -- 33 -- -- -- (G) (H/G = 1.67) 0.9 mm 153 -- 63 61
-- (H/G = 1.1) (H/G = 3.33) (H/G = 5.56) 0.3 mm 86 -- -- -- 18 (H/G
= 3.33) (H/G = 28.3)
[0050] As described above, it was confirmed that (1) upon narrowing
the gap G, and (2) upon extending the overhang amount H, the number
of particles reduced.
[0051] FIG. 5 is a graph showing a relationship between a ratio H/G
and the number of the particles. In FIG. 5, horizontal axis
represents the aspect ratio of the overhang amount H and the gap G,
and the results of the experiments are plotted therein. This graph
shows that upon increasing the ratio H/G, the number of particles
reduces. Generally, the number of particles counted in the
experiments was desired to be 100 or less. It can be understood
from the graph in FIG. 5 that when the ratio H/G was about 1.5 or
more, the number of particles became 100 or less.
[0052] The embodiment employs a configuration in which the
substrate 90 is arranged on the upper surface of the table 52 so
that the ratio H/G becomes 1.5 or more, for carrying out etching
process. With this arrangement, it becomes difficult for the
etching gas excited by plasma to flow into the gap 92 formed
between the plate 53 and the substrate 90. Therefore, generation of
particles caused by the etching gas which acts on the side surface
of the table 52 can be suppressed, and the substrate can be
prevented from contamination due to the particles.
[0053] In particular, it is preferable to set the gap G defined
from the upper surface of the plate 53 to the bottom surface of the
substrate 90 (the upper surface of the table 52) to 1mm or more.
With this configuration, even if the etching products 110 with
conductive properties deposit on the upper surface of the plate 53,
an occurrence of an abnormal electrical discharge between the
etching products 110 and the substrate 90 can be prevented.
[0054] The technical range of the present invention is not limited
to the above-described embodiment, and includes various
modifications of the above-described embodiment within the scope of
the intention of the present invention. That is, specific materials
or configurations suggested in the embodiment are merely examples
and can be suitably modified.
INDUSTRIAL APPLICABILITY
[0055] According to the present invention, an etching gas excited
by plasma hardly flows into a gap formed between a frame member and
a subject substrate, and thus, generation of particles caused by an
etching gas which acts on a side surface of a table can be
suppressed. Therefore, the substrate can be prevented from
contamination due to the particles.
* * * * *