U.S. patent application number 10/514844 was filed with the patent office on 2005-10-13 for baffle plate and plasma etching device having same.
This patent application is currently assigned to Tokyo Electron Korea Ltd.. Invention is credited to Kim, Moon Hwan, Lee, Jeung Woo, Moon, Young Jae.
Application Number | 20050224179 10/514844 |
Document ID | / |
Family ID | 29546332 |
Filed Date | 2005-10-13 |
United States Patent
Application |
20050224179 |
Kind Code |
A1 |
Moon, Young Jae ; et
al. |
October 13, 2005 |
Baffle plate and plasma etching device having same
Abstract
A plasma etching device includes a baffle plate having a
plurality of slots for preventing leakage of plasma gas generated
during a plasma generating process while discharging other
materials such as exhaust gas, residual products and particles
generated during the process. The slots, each of which extends in
the form of a curve from an inner circumference of the baffle plate
to an outer circumference thereof, expedites the discharge of the
exhaust gas and residual products. Therefore, the plasma generating
progresses more smoothly and, further, an amount of discharged
exhaust gas is increased.
Inventors: |
Moon, Young Jae;
(Gyeonggi-do, KR) ; Lee, Jeung Woo;
(Chungcheongbuk-do, KR) ; Kim, Moon Hwan; (Seoul,
KR) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND, MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
Tokyo Electron Korea Ltd.
325-230, Dongcheon-ri, Suji-eup, Yongin
Gyeonggi-do
KR
449-843
|
Family ID: |
29546332 |
Appl. No.: |
10/514844 |
Filed: |
November 18, 2004 |
PCT Filed: |
May 22, 2003 |
PCT NO: |
PCT/KR03/01006 |
Current U.S.
Class: |
156/345.29 |
Current CPC
Class: |
H01J 37/32834
20130101 |
Class at
Publication: |
156/345.29 |
International
Class: |
C23F 001/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 22, 2002 |
KR |
10-2002-0028360 |
Claims
1. A plasma generating device installed within a plasma generating
chamber and including a baffle plate having a plurality of slots
for discharging exhaust gas or residual products, wherein the
plurality of slots are extended from an inner circumference of the
baffle plate to an outer circumference thereof in the form of a
curve.
2. The device of claim 1, wherein each of the plurality of slots
has a predetermined width.
3. The device of claim 1, wherein the distance between first end
portions of two neighboring slots is identical to the distance
between second end portions thereof.
4. The device of claim 1, wherein each of the plurality of slots
has a cross section in which an upper width thereof is larger than
a lower width thereof.
5. The device of claim 4, wherein the upper width of each slot
ranges from about 1.6 to 1.8 mm while the lower width thereof is
about 1.0 mm.
6. The device of claim 1, wherein a portion on the baffle plate in
which the plurality of slots are formed is bent upward or downward
in a predetermined angle.
7. The device of claim 6, wherein the slot formation portion of the
baffle plate is bent upward or downward within an angular range of
about 0 to 45.degree..
8. The device of claim 1, wherein the slot formation portion of the
baffle plate is bent upward or downward in the form of an arc.
9. The device of claim 1, wherein the slot formation portion of the
baffle plate is bent upward or downward two or more times in a
predetermined angle.
10. The device of claim 1 or 9, wherein the plasma generating
device is a plasma etching device.
11. A plasma generating device installed within a plasma generating
chamber and including a baffle plate having a plurality of slots,
wherein the plurality of slots is extended from an inner
circumference of the baffle plate to an outer circumference thereof
in the form of a curve.
12. The device of claim 11, wherein each of the plurality of slots
has a predetermined width.
13. The device of claim 11 or 12, wherein a distance between first
end portions of the neighboring slots is identical to a distance
between second end portions thereof.
14. The device of claim 11 or 12, wherein each of the plurality of
slots has a cross section in which an upper width thereof is larger
than a lower width thereof.
15. The device of claim 14, wherein the upper width of each slot
ranges from about 1.6 to 1.8 mm while the lower width thereof is
about 1.0 mm.
16. The device of claim 11 or 12, wherein a portion on the baffle
plate in which the plurality of slots are formed is bent upward or
downward in a predetermined angle.
17. The device of claim 16, wherein the slot formation portion of
the baffle plate is bent upward or downward within an angular range
from 0 to 45.degree..
18. The device of claim 11 or 12, wherein the slot formation
portion of the baffle plate is bent upward or downward in the form
of an arc.
19. The device of claim 11 or 12, wherein the slot formation
portion of the baffle plate is bent upward or downward two or more
times in a predetermined angle.
20. A plasma generating device installed within a plasma generating
chamber and including a baffle plate having a plurality of slots
for discharging exhaust gas or residual products, wherein the
plurality of slots are extended linearly from an inner
circumference of the baffle plate to an outer circumference thereof
diagonally in a radial direction.
21. The device of claim 20, wherein each of the plurality of slots,
which are linearly extended from the inner circumference of the
baffle plate to the outer circumference thereof diagonally to the
radial direction, is bent at least one time.
22. The device of claim 1, wherein each of the plurality of slots
has a cross-section of a sand watch shape in which an upper width
is larger than a lower width and a middle width is smaller than the
lower width.
23. The device of claim 22, wherein the upper width of each slot
ranges from about 1.6 to 1.8 mm, the lower width ranges from about
1.1 to 1.5 mm and the middle width is about 1.0 mm.
24. A plasma generating device installed within a plasma generating
chamber and including a baffle plate having a plurality of slots
for discharging exhaust gas, residual products, and the like,
wherein a portion on the baffle plate in which the plurality of
slots are formed (hereinafter referred to as a slot formation
portion) is bent upward or downward in a predetermined angle.
25. The device of claim 24, wherein the slot formation portion of
the baffle plate is bent upward or downward at least two times.
26. A plasma generating device installed within a plasma generating
chamber and including a baffle plate having a plurality of slots
for discharging exhaust gas, residual products, and the like,
wherein a portion on the baffle plate in which the plurality of
slots are formed (hereinafter, a slot formation portion) is bent
upward or downward in the form of an arc.
27. The device of claim 11, wherein each of the plurality of slots
has a cross-section of a sand watch shape in which an upper width
thereof is larger than a lower width thereof and a middle width
thereof is smaller than the lower width.
28. The device of claim 27, wherein the upper width of each slot
ranges from about 1.6 to 1.8 mm, the upper width is about 1.1 to
1.5 mm and the middle width ranges from about 1.0 mm.
Description
TECHNICAL FIELD
[0001] The present invention relates to a plasma generating device;
and, more particularly, to a plasma etching device including a
baffle plate for preventing leakage of plasma while efficiently
discharging such other materials as exhaust gas, residual products
and particles, wherein the baffle plate is connected to an inner
wall of a plasma processing chamber in such a manner as to surround
a lower electrode installed within the chamber.
BACKGROUND ART
[0002] As well known in the art, plasma refers to a state of matter
electrically neutral and highly ionized with ions (+) and electrons
(-) of a same density. A device using plasma is, for example, a
discharge tube.
[0003] In the course of manufacturing a semiconductor or TFT LCD
integration circuit, a metal layer is formed in a metalization step
for the wiring of devices formed on a silicon substrate and a
contact hole is formed at an insulation layer below the metal layer
to electrically connect the devices on the silicon substrate to the
metal layer. In general, the contact hole is formed by performing a
dry etching on the insulation layer, for example, an oxide layer,
by using plasma.
[0004] Referring to FIG. 1, there is provided a conventional plasma
etching device 100. A lower electrode 102 for accommodating thereon
an object to be etched, e.g., a wafer, is installed within a
chamber 101 and an upper electrode 103 is installed above the lower
electrode 102 with a predetermined distance maintained
therebetween. Formed at the upper electrode 103 is a plurality of
process gas inlets 104 through which a process gas (e.g.,
C.sub.4F.sub.8, C.sub.3F.sub.8, C.sub.5F.sub.8, CF.sub.4,
CHF.sub.3, CH.sub.2F.sub.2, CO, Ar, O.sub.2, N.sub.2 and/or
H.sub.2) is introduced into the chamber 101. The process gas
introduced into the chamber 101 is converted into a plasma-state
gas (i.e., gas composed of radicals, ions, electrons, etc.) by a RF
voltage applied between the upper electrode 103 and the lower
electrode 102 to be used for the processing of the wafer. Further,
prepared at a lower part of the chamber 101 is an exhaust system
105 for discharging an exhaust gas or residual products generated
during the conversion of the process gas into the plasma-state gas.
The exhaust system 105 is, for example, a turbo molecular pump
(TMP). A baffle plate 10 is connected to an inner wall of the
chamber 101 in such a manner as to surround the lower electrode 102
to thereby confine a plasma generation space 110, i.e., a space
between the upper electrode 103 and the lower electrode 102, and
prevent leakage of plasma generated in the plasma generation space
110. Formed at the baffle plate 10 is a plurality of openings or
slots sized to be adequate for discharging the residual products or
exhaust gas while preventing leakage of the plasma. The baffle
plate 10 is connected to an upper bellows cover 130 by driving a
screw into the upper bellows cover 103 through a screw hole 150
(shown in FIG. 2).
[0005] FIG. 2 provides a perspective view of a prior art baffle
plate 120. The baffle plate 120 is of a donut shape having a
circular opening 122 formed at the center thereof. A plurality of
long slots 121, each of which is linearly extended from an inner
circumference of the baffle plate 120 to an outer circumference
thereof in a radial direction, is arranged along the circumference
of the baffle plate 120. Exhaust gas or residual products (e.g.,
impurities, electrons, ions, radicals, etc.) generated during the
plasma processing flow into the lower portion of a chamber through
the slots 121 of the baffle plate 120 and then is discharged to the
outside of the chamber by an exhaust system. FIGS. 3A and 3B
respectively depict an enlarged perspective view and a plane view
of a portion A in FIG. 2.
[0006] As shown in FIGS. 3A and 3B, the plurality of slots 121,
each of which has a predetermined width Ts, is linearly extended on
the baffle plate 120 in a radial direction. In general, the width
Ts of each of the slots 121 is defined as about 1 mm to prevent
leakage of the plasma through the slots 121. Accordingly, a
distance T2 between end portions of slots 121 around the inner
circumference of the baffle plate 120 is found to be different from
a distance T1 between the other end portions of the slots 121
around the outer circumference of the baffle plate 120. That is, T1
is larger than T2. Therefore, a dead area incapable of discharging
exhaust gas or residual products is large in the conventional
baffle plate 120, so that the processing efficiency of the plasma
etching device is reduced, resulting in an increase in the
manufacturing cost of the semiconductor or the integrated circuit.
In order to reduce such dead area, attempts have been made to
increase the entire width of each of the slots 121 or increase it
gradually as it goes toward the outer circumference of the baffle
plate 120 while maintaining the width of each of the slots 121 to
be about 1 mm at its one end portion around the inner circumference
of the baffle plate. However, it is inevitable in both cases that
plasma leakage is increased, thereby lowering plasma etching
efficiency.
DISCLOSURE OF THE INVENTION
[0007] It is, therefore, an object of the present invention to
provide a plasma generating device, particularly a plasma etching
device, using a baffle plate having slots adequate for preventing
leakage of plasma while efficiently discharging exhaust gas and
residual products.
[0008] In accordance with a preferred embodiment of the present
invention, there is provided a plasma generating device installed
within a plasma generating chamber and including a baffle plate
having a plurality of slots for discharging exhaust gas or residual
products, wherein the plurality of slots are extended from an inner
circumference of the baffle plate to an outer circumference thereof
in the form of a curve.
[0009] Each of the plurality of slots has preferably a
predetermined width. A distance between first end portions of the
neighboring slots may be identical to a distance between second end
portions thereof.
[0010] It is preferable that each of the plurality of slots has a
cross section in which an upper width is larger than a lower width.
Preferably, the upper width of each slot is about 1.6 to 1.8 mm
while the lower width thereof is about 1.0 mm.
[0011] A portion on the baffle plate in which the plurality of
slots are formed (hereinafter referred to as a slot formation
portion) may be bent upward or downward in a predetermined angle.
Preferably, the slot formation portion of the baffle plate is bent
upward or downward within an angular range of about 0 to
45.degree..
[0012] The slot formation portion of the baffle plate may be bent
upward or downward in the form of an arc.
[0013] The slot formation portion of the baffle plate may be bent
upward or downward two or more times in a predetermined angle.
[0014] The plasma generating device may be a plasma etching
device.
[0015] In accordance with another preferred embodiment of the
present invention, there is provided a plasma generating device
installed within a plasma generating chamber and including a baffle
plate having a plurality of slots for discharging exhaust gas or
residual products, wherein the plurality of slots are extended
linearly from an inner circumference of the baffle plate to an
outer circumference thereof diagonally to a radial direction.
[0016] Preferably, each of the plurality of slots, which are
linearly extended from the inner circumference of the baffle plate
to the outer circumference thereof diagonally to the radial
direction, is bent at least one time.
BRIEF DESCRIPTION OF DRAWINGS
[0017] The above and other objects and features of the present
invention will become apparent from the following description of
preferred embodiments given in conjunction with the accompanying
drawings, in which:
[0018] FIG. 1 illustrates a conventional plasma etching device;
[0019] FIG. 2 provides a perspective view of a prior art baffle
plate;
[0020] FIGS. 3A and 3B respectively provide an enlarged perspective
view and a plan view of a portion A in FIG. 2;
[0021] FIG. 4 depicts a perspective view of a baffle plate in
accordance with a first preferred embodiment of the present
invention;
[0022] FIGS. 5A and 5B respectively set forth an enlarged
perspective view and a plan view of a portion B in FIG. 4;
[0023] FIGS. 6A and 6B offer cross-sectional views taken by a line
C-C' shown in FIG. 5A;
[0024] FIGS. 7A to 7D illustrate various modifications of the
baffle plate in accordance with the present invention;
[0025] FIGS. 8A and 8B respectively show a partial perspective view
of a baffle plate in accordance with a second embodiment of the
present invention; and
[0026] FIGS. 9A and 9B respectively provide a partial perspective
view and a plan view of an exemplified modification of the baffle
plate in accordance with the second embodiment of the present
invention.
BEST MODE FOR CARRYING OUT THE INVENTION
[0027] Referring to FIG. 1, there is provided a plasma etching
device having a baffle plate in accordance with a first preferred
embodiment of the present invention. An upper electrode 103 and a
lower electrode 102 are installed opposite to each other within a
chamber 101. The lower electrode 102 accommodates thereon an object
to be processed (i.e., an object to be etched), e.g., a wafer.
Formed at the upper electrode 103 is a plurality of process gas
inlets 104 through which process gas (e.g., C.sub.4F.sub.8,
C.sub.3F.sub.8, C.sub.5F.sub.8, CF.sub.4, CHF.sub.3,
CH.sub.2F.sub.2, CO, Ar, O.sub.2, N.sub.2 and/or H.sub.2) is
introduced into the chamber 101. The process gas introduced into
the chamber 101 is converted into plasma-state gas by a RF voltage
applied between the upper electrode 103 and the lower electrode 102
to be used to process (etch) the wafer. During the conversion of
the process gas into the plasma-state gas, there are generated
residual products such as impurities, electrons, ions and radicals.
Thus, an exhaust system 105 for discharging such residual products
and exhaust gas is prepared at a lower part of the chamber 101. The
exhaust system 105 may be, for example, a turbo molecular pump
(TMP).
[0028] Further, a baffle plate 10 is installed within the chamber
101. Specifically, the baffle plate 10 is connected to an upper
bellows cover 130 by driving a screw into the upper bellows cover
103 through a screw hole 150 (shown in FIG. 4). At this time, the
baffle plate 10 is installed in such a manner that an inner
circumference thereof surrounds the lower electrode 102 while an
outer circumference thereof is connected to an inner wall of the
chamber 101 to thereby prevent leakage of plasma generated in a
plasma generation space 110 (i.e., a space formed between the upper
electrode 103 and the lower electrode 102). Formed at the baffle
plate 10 is a plurality of openings or slots having a size adequate
for discharging the residual products and the exhaust gas while
preventing leakage of the plasma.
[0029] FIG. 4 provides a perspective view of the baffle plate 10 in
accordance with a first preferred embodiment of the present
invention. The baffle plate 10 is of a donut shape having an inner
diameter of, e.g., about 250 mm and an outer diameter of, e.g.,
about 366 mm. The inner circumference of the baffle plate 10
surrounds the lower electrode 102 while the outer circumference
thereof is fixed at the upper bellows cover 130 to be brought into
tight contact with the inner wall of the chamber 101. The baffle
plate 10 serves to confine the plasma generation area. Though the
baffle plate 10 has the donut shape in accordance with the first
preferred embodiment of the present invention, it is preferable to
modify the shape of the baffle plate 10 depending on the shape of
the chamber 101. For example, the baffle plate may have a shape of
a rectangular plate. Formed at the baffle plate 10 is a plurality
of long slots 11 for use in discharging exhaust gas or residual
products as fast as possible while preventing leakage of plasma
process gas.
[0030] Each of the slots 11 has a predetermined width (about 1 mm)
and is extended from the inner circumference of the baffle plate 10
to the outer circumference thereof. At this time, each of the slots
11 is extended in the form of a curve. Thus, if the inner diameter
and the outer diameter of the baffle plate 10 are identical with
those of the conventional baffle plate as described before with
reference to FIG. 2 and FIGS. 3A and 3B, the length of each of the
slots 11 is found to be larger than that of each slot in the
conventional baffle plate in which slots are extended linearly in a
radial direction. Accordingly, an open area is enlarged and, as a
result, a larger amount of exhaust gas or residual products can be
discharged out through the slots 11.
[0031] Referring to FIGS. 5A and 5B, there are provided an enlarged
perspective view and a plan view of a portion B in FIG. 4. As
shown, the slots 11 are formed at the baffle plate 10 in a manner
that a distance T3 between first end portions of the neighboring
slots 11 is identical to a distance T4 between second end portions
of the slots 11. Herein, T3 and T4 can have the same value since
the slots 11 are extended from the inner circumference of the
baffle plate 10 to the outer circumference of the baffle plate 10
in the form of a curve.
[0032] For example, assume that there is a donut-shaped baffle
plate having an inner diameter of about 250 mm and an outer
diameter of about 366 mm. If 360 slots respectively having a width
of about 1 mm and a length of about 40 mm are formed at the baffle
plate linearly in a radial direction in accordance with prior art,
the total area of open portions formed by the slots is calculated
as about 14400 mm.sup.2.
[0033] On the other hand, if slots having a width of about 1 mm are
formed at the same baffle plate in the form of a curve in
accordance with the present invention, each the slots can be formed
to have a curvilinear length of about 45 mm. If the number of the
slots formed at the baffle plate is 360, the total area of open
portions formed by the slots is calculated to be about 16200
mm.sup.2. Thus, the total area of the open portions in the baffle
plate having the slots formed in accordance with the present
invention increases by about 12.5% of that of the baffle plate
having the slots formed in accordance with the prior art.
[0034] FIG. 7A exemplifies a modification of the baffle plate 10 in
accordance with the first preferred embodiment of the present
invention. If a slot formation portion (meaning a portion on which
slots are formed) of the baffle plate having an inner diameter of
about 250 mm and an outer diameter of about 350 mm is bent downward
by a predetermined angle ( 0 ), e.g., about 22.degree., the length
of each slot is increased to about 53 mm. If 360 slots are formed,
the area of open portions of the baffle plate formed by the slots
amounts to about 19080 mm.sup.2. Thus, by forming the slots in the
form of a curve and bending the slot formation portions as
described above, the area of the slots can be increased, resulting
in increase of the total area of open portions of the baffle
plate.
[0035] FIGS. 6A and 6B are cross-sectional views taken by a line
C-C' in FIG. 5A. In FIG. 6A, an upper width P1 of each of the slots
11 in the baffle plate 10 is greater than a lower width P2 thereof.
Thus, it can be prevented that materials generated during a plasma
process, e.g., polymer, get stuck to walls of the slots 11 to
thereby clog the slots 11, which frequently happens during a plasma
process using a conventional baffle plate. Preferably, the upper
width P1 is about 1.6 to 1.8 mm while the lower width P2 is about 1
mm.
[0036] Further, as shown in FIG. 6B, each of the slots 11 can have
a cross-section of a sand watch shape. At this time, it is
preferable to define the upper width P1 as about 1.6 to 1.8 mm, the
lower width P2 as about 1.1 to 1.5 mm and a middle width P3 as
about 1 mm. Further, if the thickness H of the baffle plate 10 is
about 3 mm, a distance H1 from an upper surface of the baffle plate
10 to the middle width P3 is preferably about 1.8 mm. More
preferably, the upper width P1, the lower width P2 and the middle
width P3 of each of the slots 11 are about 1.6 mm, 1.2 mm and 1 mm,
respectively.
[0037] FIGS. 7A to 7D exemplify various modifications of the shape
of the baffle plate in accordance with the present invention, in
which slot formation portions on baffle plates 20 and 30 are
modified in various ways in order to increase the length of slots
formed thereon in the form of a curve.
[0038] As shown in FIGS. 7A and 7B, the slot formation portions of
the baffle plates 20 and 30 are bent downward (FIG. 7A) or upward
(FIG. 7B) by a predetermined angle .phi. while an outer
circumference of each of the baffle plates 20 and 30 is maintained
at a certain value. At this time, the angle .phi. is determined so
as not to interfere with the plasma process. Preferably, the angle
.phi. is determined within an angular range of 0.degree. to
45.degree. and, more preferably, it is 22.degree..
[0039] Further, as shown in FIG. 7C, a slot formation portion on
the baffle plate 40 can be bent downward in an arch, if necessary.
It is also possible that the slot formation portion is bent upward
in the form of an arc though it is not shown in the drawing (not
illustrated).
[0040] Still further, a slot formation portion on the baffle plate
50 can be bent downward two times, i.e. in the form of a stair, as
shown in FIG. 7D. At this time, the slot formation portion can be
bent upward two times as well though it is not illustrated in the
drawing.
[0041] Still further, a slot formation portion can be bent three or
more times though it is not illustrated herein.
[0042] Referring to FIGS. 8A and 8B, there are respectively
provided a partial enlarged perspective view and a plan view of a
baffle plate 10a in accordance with a second preferred embodiment
of the present invention. The baffle plate 10a has a donut shape
with an inner diameter of, e.g., about 250 mm and an outer
circumference of, e.g., about 366 mm. The baffle plate 10a is
connected to an upper bellow cover 130 in a manner that its inner
circumference surrounds a lower electrode while an outer
circumference thereof is in tight contact with an inner wall of the
chamber 101. The baffle plate 10a serves to confine a plasma
generation space. Though the baffle plate 10a has a donut shape in
accordance with the present invention, it is also preferable that
it has another shape, e.g., the shape of a square plate, depending
on the shape of the chamber 101. Formed at the baffle plate 10a is
a plurality of long slots 11a for discharging an exhaust gas or
residual products while preventing leakage of a plasma process
gas.
[0043] In the second preferred embodiment, each of the slots 11a
has a predetermined width (about 1 mm) and is linearly extended
from the inner circumference to the outer circumference of the
baffle plate 10a diagonally to a radial direction. Thus, if the
inner diameter and the outer diameter of the baffle plate 10a are
identical with those of the conventional baffle plate as described
before, the length of each of the slots 11a is found to be larger
than that of each slot in the conventional baffle plate in which
slots are extended linearly in a radial direction. Accordingly, an
open area is enlarged and, as a result, a larger amount of exhaust
gas or residual products can be discharged out through the slots
11.
[0044] FIGS. 9A and 9B respectively depict a partial enlarged
perspective view and a plan view of a baffle plate 10b as a
modification of the baffle plate 10a in accordance with the second
preferred embodiment of the present invention. As shown, the slots
11b in the baffle plate 10b are bent one time when they are
linearly extended from an inner circumference to an outer
circumference of the baffle plate 10b diagonally to a radius
direction. Thus, the length of each of the slots 11b can be further
lengthened. As a result, a greater amount of an exhaust gas and
residual products can be discharged out through the slots 11b.
Though the slots 11b are bent one time in the description, the
slots 11b can be bent two or more times if required.
[0045] In the above-described baffle plates in accordance with the
present invention, the length of each slot is increased while the
width thereof is maintained as about 1 mm. Accordingly, the open
area is increased, allowing a greater amount of exhaust gas or
residual products to be discharged while preventing leakage of
plasma during a plasma process. As a result, manufacturing costs of
semiconductors or integrated circuits can be reduced.
[0046] As described above, by forming slots in the form of a curve
or linearly extending the slots diagonally to a radial direction
and/or by modifying a slot formation portion in various ways while
maintaining a current outer diameter of the baffle plate, exhaust
gas or residual products generated during a plasma process can be
effectively discharged out. Accordingly, the performance of the
plasma process can be improved and a larger amount of process gas
can be flowed into the chamber. As a result, the efficiency of the
plasma process is greatly increased and manufacturing costs can be
reduced.
[0047] While the invention has been shown and described with
respect to the preferred embodiments, it will be understood by
those skilled in the art that various changes and modifications may
be made without departing from the spirit and scope of the
invention as defined in the following claims.
* * * * *