U.S. patent application number 13/109365 was filed with the patent office on 2011-11-24 for plasma processing apparatus.
This patent application is currently assigned to TOKYO ELECTRON LIMITED. Invention is credited to Hachishiro IIZUKA.
Application Number | 20110284165 13/109365 |
Document ID | / |
Family ID | 44971468 |
Filed Date | 2011-11-24 |
United States Patent
Application |
20110284165 |
Kind Code |
A1 |
IIZUKA; Hachishiro |
November 24, 2011 |
PLASMA PROCESSING APPARATUS
Abstract
Provided is a plasma processing apparatus that is capable of
promoting improvement of in-plane uniformity of a process compared
to a conventional technology, promoting miniaturization of the
apparatus and improvement of processing efficiency, and easily
changing an interval between an upper electrode and a lower
electrode. The plasma processing apparatus includes a lower
electrode provided in a processing chamber; an upper electrode
having a function of a shower head and capable of moving up and
down; a lid provided at an upper side of the upper electrode and
airtightly blocking an upper opening of the processing chamber; a
plurality of exhaust holes formed on a facing surface of the upper
electrode; an annular member capable of moving up and down with the
upper electrode by being formed to protrude downward along a
circumferential portion of the upper electrode, and forming a
processing space surrounded by the lower electrode, the upper
electrode, and the annular member at a descending location; and a
coil disposed on an inner wall portion of the annular member and
accommodated in a container formed of a dielectric material.
Inventors: |
IIZUKA; Hachishiro;
(Nirasaki City, JP) |
Assignee: |
TOKYO ELECTRON LIMITED
Tokyo
JP
|
Family ID: |
44971468 |
Appl. No.: |
13/109365 |
Filed: |
May 17, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61348529 |
May 26, 2010 |
|
|
|
Current U.S.
Class: |
156/345.34 |
Current CPC
Class: |
H01J 37/3211 20130101;
H01J 37/3244 20130101; H01L 21/67069 20130101; H01J 37/321
20130101; H01J 37/32431 20130101; H01J 37/32449 20130101 |
Class at
Publication: |
156/345.34 |
International
Class: |
C23F 1/08 20060101
C23F001/08 |
Foreign Application Data
Date |
Code |
Application Number |
May 17, 2010 |
JP |
2010-113262 |
Claims
1. A plasma processing apparatus comprising: a lower electrode,
which is provided in a processing chamber and also serves as a
holding stage for holding a substrate thereon; an upper electrode,
which is provided in the processing chamber to face the lower
electrode, has a function of a shower head for supplying a gas from
a plurality of gas ejection holes formed on a facing surface facing
the lower electrode toward the substrate in a shower shape, and is
capable of moving up and down so that an interval between the upper
electrode and the lower electrode is changeable; a lid, which is
provided at an upper side of the upper electrode and airtightly
blocks an upper opening of the processing chamber; a plurality of
exhaust holes formed on the facing surface; an annular member,
which is provided to protrude downward along a circumferential
portion of the upper electrode to be capable of moving up and down
with the upper electrode, and forms a processing space surrounded
by the lower electrode, the upper electrode, and the annular member
at a descending location; and a coil, which is provided on an inner
wall part of the annular member and accommodated in a container
formed of a dielectric material so as to be airtightly isolated
from the processing space, and generates induced plasma by applying
high-frequency power.
2. The plasma processing apparatus of claim 1, wherein an opening,
which is freely opened and shut so as to transfer into and out the
substrate, is formed at a side wall of the processing chamber
between the lower electrode and the upper electrode, and the
substrate is transferred into and out while the annular member is
ascended.
3. The plasma processing apparatus of claim 1, wherein the annular
member is formed of aluminum covered by an insulating film.
4. The plasma processing apparatus of claim 1, wherein the
container formed of the dielectric material has an air or inert gas
atmosphere under a pressure higher than or equal to 1330 Pa and
lower than or equal to an atmospheric pressure.
5. The plasma processing apparatus of claim 1, wherein the coil is
formed of a hollow conductor having a pipe shape, and a temperature
adjusting medium is introduced into the coil.
6. The plasma processing apparatus of claim 1, wherein a frequency
of the high-frequency power applied to the coil is in the range
from 450 KHz to 2 MHz.
7. The plasma processing apparatus of claim 1, wherein the annular
member and the upper electrode are maintained electrically
conducted to each other, and the annular member is connected to
ground potential via a flexible sheet cable formed of a metal sheet
having a surface covered with an insulating layer.
8. The plasma processing apparatus of claim 1, wherein driving
means, which moves the annular member and the upper electrode up
and down is multi-axially driven using an electric cylinder.
Description
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS
[0001] This application claims the benefit of Japanese Patent
Application No. 2010-113262, filed on May 17, 2010, in the Japan
Patent Office, and U.S. Patent Application No. 61/348,529, filed on
May 26, 2010, in U.S. Patent and Trademark Office, the disclosures
of which are incorporated herein in there entireties by
reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a plasma processing
apparatus.
[0004] 2. Description of the Related Art
[0005] Conventionally, in fields of manufacturing a semiconductor
device or the like, a shower head for supplying a gas toward a
substrate, such as a semiconductor wafer or the like, in a shower
shape is used. In other words, for example, a holding stage for
holding a substrate is provided inside a processing chamber, and a
shower head is provided to face the holding stage, in a plasma
processing apparatus which performs a plasma etching process on a
substrate, such as a semiconductor wafer or the like. A plurality
of gas ejection holes are formed on a surface facing the shower
head, which faces the holding stage, and the gas is supplied toward
the substrate from the gas ejection holes in a shower shape.
[0006] It is well known the plasma processing apparatus which
includes a configuration of exhausting a gas from around the
holding stage downward so as to make a flow of the gas inside the
processing chamber uniform. Also, a plasma processing apparatus
configured to exhaust a gas from around a shower head toward above
a processing chamber is known (for example, refer to Patent
Document 1).
[0007] Also, a plasma processing apparatus having counter
electrodes provided in a processing chamber, and a coil provided on
an outer side wall of the processing chamber and generating
inductively coupled plasma (ICP) is known (for example, refer to
Patent Document 2). Also, a plasma processing apparatus, wherein a
coil for generating inductively coupled plasma is disposed inside a
processing chamber while being surrounded by a dielectric, is known
(for example, refer to Patent Document 3). [0008] [Patent Document
1] Japanese Patent No. 2662365 [0009] [Patent Document 2] Japanese
Laid-Open Patent Publication No. hei 8-64540 [0010] [Patent
Document 3] Japanese Laid-Open Patent Publication No. hei
10-98033
SUMMARY OF THE INVENTION
[0011] In the above conventional technology, a plasma processing
apparatus is configured to exhaust a gas from around a holding
stage (substrate) toward below a processing chamber, or from around
a shower head toward above the processing chamber. Accordingly, the
gas supplied from the shower head flows from a central portion of
the substrate toward a circumferential portion of the substrate,
and thus processing on the central portion and the circumferential
portion of the substrate may easily differ, and uniformity of a
processing surface may deteriorate. Also, since an exhaust flow
path is required to be provided around the holding stage
(substrate) or around the shower head, a volume inside the
processing chamber becomes quite large compared to that of the
substrate accommodated in the processing chamber. Thus, it is
difficult to promote miniaturization of an entire apparatus since
there are many unnecessary spaces. Also, accompanied by a big size
of the apparatus, a standby time to start the apparatus increases
while initial processing changes increase, and thus processing
efficiency is deteriorated.
[0012] Further, in a capacitive-coupled type plasma processing
apparatus, wherein a shower head also serves as an upper electrode
and a holding stage also serves as a lower electrode, an interval
between the upper electrode (shower head) and the lower electrode
(holding state) is required to vary. However, since the inside of a
processing chamber is depressurized, a driving source requires
large power so as to move the upper electrode (shower head) or the
lower electrode (holding stage) up and down while resisting a
pressure difference between the inside and outside of the
processing chamber, and thus energy required to drive the
capacitive-coupled type plasma processing apparatus increases.
[0013] To solve the above and/or other problems, the present
invention provides a plasma processing apparatus that is capable of
promoting improvement of in-plane uniformity of a process compared
to a conventional technology, promoting miniaturization of the
apparatus and improvement of processing efficiency, and easily
changing an interval between an upper electrode and a lower
electrode.
[0014] According to an embodiment of the present invention, there
is provided a plasma processing apparatus including: a lower
electrode, which is provided in a processing chamber and also
serves as a holding stage for holding a substrate thereon; an upper
electrode, which is provided in the processing chamber to face the
lower electrode, has a function of a shower head for supplying a
gas from a plurality of gas ejection holes formed on a facing
surface facing the lower electrode toward the substrate in a shower
shape, and is capable of moving up and down so that an interval
between the upper electrode and the lower electrode is changeable;
a lid, which is provided at an upper side of the upper electrode
and airtightly blocks an upper opening of the processing chamber; a
plurality of exhaust holes formed on the facing surface; an annular
member, which is provided to protrude downward along a
circumferential portion of the upper electrode to be capable of
moving up and down with the upper electrode, and forms a processing
space surrounded by the lower electrode, the upper electrode, and
the annular member at a descending location; and a coil, which is
provided on an inner wall part of the annular member and
accommodated in a container formed of a dielectric material so as
to be airtightly isolated from the processing space, and generates
induced plasma by applying high-frequency power.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The above and other features and advantages of the present
invention will become more apparent by describing in detail
exemplary embodiments thereof with reference to the attached
drawings in which:
[0016] FIG. 1 is a longitudinal-sectional view of a configuration
of main parts of a plasma processing apparatus, according to an
embodiment of the present invention;
[0017] FIG. 2 is a magnified longitudinal-sectional view of a
configuration of main parts of the plasma processing apparatus of
FIG. 1;
[0018] FIG. 3 is a magnified longitudinal-sectional view of a
configuration of main parts of the plasma processing apparatus of
FIG. 1; and
[0019] FIG. 4 is a longitudinal-sectional view of a shower head of
the plasma processing apparatus of FIG. 1 in a risen state.
EXPLANATION ON REFERENCE NUMERALS
[0020] 11: gas ejection hole [0021] 13: exhaust hole [0022] 100:
shower head (upper electrode) [0023] 200: plasma etching apparatus
[0024] 201: processing chamber [0025] 202: holding stage (lower
electrode) [0026] 205: lid [0027] 212: processing space [0028] 220:
annular member [0029] 230: quartz container [0030] 240: ICP coil
[0031] 270: elevating mechanism
DETAILED DESCRIPTION OF THE INVENTION
[0032] Hereinafter, the present invention will be described in
detail by explaining exemplary embodiments of the invention with
reference to the attached drawings.
[0033] FIG. 1 is a view schematically showing a cross-sectional
configuration of a plasma etching apparatus 200, according to an
embodiment of a plasma processing apparatus of the present
invention, and FIG. 2 is a cross-sectional view schematically
showing a configuration of a shower head 100 provided in the plasma
etching apparatus 200 of FIG. 1. The plasma etching apparatus 200
according to the present embodiment includes main parts of a
capacitive-coupled type parallel-plate plasma etching apparatus,
wherein electrode plates face each other so as to be arranged up
and down and parallel to each other, and a plasma-generating power
source (not shown) is connected to the capacitive-coupled type
parallel-plate plasma processing apparatus.
[0034] As shown in FIG. 2, the shower head 100 includes a laminated
body 10 in which two plate-shaped members of a lower member 1 and
an upper member 2 disposed on the lower member 1 are laminated. The
lower member 1 and the upper member 2 are formed of, for example,
aluminum or the like, on each surface of which an anode oxidation
process is performed. As shown in FIG. 1, the shower head 100 is
provided in a processing chamber 201 of the plasma etching
apparatus 200 to face a holding stage 202, on which a semiconductor
wafer (substrate) is held. In other words, the shower head 100 is
provided so that the lower member 1 shown in FIG. 2 includes a
facing surface 14 facing the holding stage 202 shown in FIG. 1.
[0035] In the laminated body 10, a plurality of gas ejection holes
11 are formed on the lower member 1 including the facing surface 14
facing the holding stage 202, and gas flow paths 12 communicating
with the gas ejection holes 11 are formed between the lower member
1 and the upper member 2. The gas ejection holes 11 supply a gas
toward a substrate (a lower side in FIG. 2) in a shower shape, as
shown in arrows in FIG. 2. Also, a gas introduction unit (not
shown) for introducing a gas into the gas flow paths 12 is formed
at a circumferential portion of the laminated body 10.
[0036] Also, a plurality of exhaust holes 13 are formed by
penetrating through the laminated body 10, i.e., through the lower
member 1 and the upper member 2. The exhaust holes 13 constitutes
an exhaust mechanism performing exhaustion so that a gas flows from
the substrate (the lower side in FIG. 2) toward an opposite side of
the substrate (an upper side in FIG. 2), as shown in dotted arrows
in FIG. 2.
[0037] Diameters of the exhaust holes 13 are, for example, about
1.2 mm, and the exhaust holes 13 are approximately evenly formed
throughout an entire area of the shower head 100 except for a
circumferential portion (a fixing portion for fixing an annular
member 220 which will be described later) of the shower head 100. A
number of the exhaust holes 13, in case of the shower head 100 for
processing a semiconductor wafer having a diameter of, for example,
12 inch (300 mm), is from about 2000 to about 2500. A shape of the
exhaust holes 13 is not limited to a circular shape, and may have,
for example, an oval shape or the like. The exhaust holes 13 also
eject a reaction product. Also, in the present embodiment, an
overall shape of the shower head 100 is a circular plate shape
corresponding to an overall shape of a semiconductor wafer
constituting a substrate to be processed.
[0038] The processing chamber (processing container) 201 of the
plasma etching apparatus 200 shown in FIG. 1 may have a cylindrical
shape formed of, for example, aluminum or the like on a surface of
which an anode oxidation process is performed, and the processing
chamber 201 is grounded. The holding stage 202, on which the
semiconductor wafer constituting a substrate to be processed is
held and which serves as a lower electrode, is provided inside the
processing chamber 201. A high-frequency electric power applying
apparatus (not shown), such as a high-frequency power source or the
like, is connected to the holding stage 202.
[0039] An electrostatic chuck 203 for electrostatically adsorbing
the semiconductor wafer thereon is provided at an upper side of the
holding stage 202. The electrostatic chuck 203 is configured by
disposing an electrode between insulating materials, and
electrostatically adsorbs the semiconductor wafer due to Coulomb
force generated by applying a direct voltage to the electrode.
Also, a flow path (not shown) for circulating a temperature
adjusting medium is provided in the holding stage 202 so that a
temperature of the semiconductor wafer adsorbed on the
electrostatic chuck 203 is adjusted to a predetermined temperature.
Also, as shown in FIG. 4, an opening 215 for transferring the
semiconductor wafer into and out of the processing chamber 201 is
formed on a side wall portion of the processing chamber 201.
[0040] The shower head 100 shown in FIG. 2 is disposed above the
holding stage 202 to face the holding stage 202 with a distance
away from the holding stage 202. Also, a pair of counter
electrodes, wherein the shower head 100 serves as an upper
electrode and the holding stage 202 serves as a lower electrode,
are formed. A predetermined process gas (etching gas) is supplied
from a gas supply source (not shown) into the gas flow path 12 of
the shower head 100.
[0041] Also a lid 205, which airtightly blocks an upper opening of
the processing chamber 201 and constitutes a ceiling portion of the
processing chamber 201, is provided above the shower head 100, and
an exhaust pipe 210 having a container shape is provided at a
central portion of the lid 205. A vacuum pump (not shown), such as
a turbo molecule pump or the like, is connected to the exhaust pipe
210, with an opening and shutting control valve, an opening and
closing mechanism, etc. disposed therebetween.
[0042] The annular member 220 having a circular annular shape
(cylindrical shape) is provided on a bottom surface of the shower
head 100 to protrude downward along the circumferential portion of
the shower head 100. The annular member 220 is formed of, for
example, aluminum or the like covered with an insulating film
(anode oxidation film or the like), and thus is maintained
electrically conducted with the shower head 100 constituting an
upper electrode.
[0043] As shown in FIG. 3, the annular member 220 includes an upper
member 221 constituting an main portion of a side wall of the
annular member 220, and a lower member 222 adhered to the bottom of
the upper member 221. A protruding portion 221a protruding inward
is formed on an upper end portion of an inner wall of the upper
member 221. Also, a container formed of a dielectric material,
which has an overall shape of a circular annular shape and a
longitudinal-sectional shape of an reversed U-shape, i.e., a quartz
container 230 formed of quartz in the present embodiment, is
provided along the inner wall of the annular member 220 so as to be
interposed between the protruding portion 221a and an upper surface
of the lower member 222.
[0044] An O-ring 231 is disposed as an airtight sealing member
between a lower end portion of the quartz container 230 and a top
surface of the lower member 222. Meanwhile, an upper end portion of
the quartz container 230 is kept pressed down by the protruding
portion 221a of the upper member 221, and accordingly, the quartz
container 230 is fixed to the annular member 220 while the inside
of the quartz container 230 and a processing space inside the
processing chamber 201 are airtightly isolated from each other.
[0045] An ICP coil 240 is provided inside the quartz container 230.
An overall shape of the ICP coil 240 is a circular annular shape,
and in the present embodiment, the ICP coil 240 is provided to wind
around the processing space a plurality of times. In the present
embodiment, the ICP coil 240 is formed of a metal having a hollow
pipe shape. A temperature adjusting medium circulating mechanism
(not shown) is connected to the ICP coil 240, and a temperature
adjusting medium circulates in a hollow space of the ICP coil
240.
[0046] Also, the ICP coil 240 is connected to a high-frequency
power source (not shown). ICP plasma is generated in a processing
space 212 that is disposed at an inner side than the quartz
container 230 by applying high-frequency power of a predetermined
frequency (for example, in the range from 450 KHz to 2 MHz) from
the high-frequency supply source. The inside of the quartz
container 230 has an air or inert gas atmosphere, and has pressure
(for example, pressure between 1330 Pa (10 Torr) and atmospheric
pressure) that does not generate discharge therein.
[0047] The ICP plasma is generated in the circumferential portion
of the processing space 212 by using the ICP coil 240, thereby
controlling plasma density in the circumferential portion of the
processing space 212. In this case, a temperature of the ICP coil
240 tends to increase, and the increasing of the temperature of the
ICP coil 240 may be prevented by circulating the temperature
adjusting medium in the ICP coil 240.
[0048] Also, when the inside of the processing chamber 201 is
opened to an air for maintenance or the like and then a process
starts again, plasma is generated by using the ICP coil 240 during
a preparation process for starting the process so that moisture or
the like adsorbed to parts in the processing chamber 201 is
detached therefrom. Accordingly, a standby time may be reduced, and
initial process changes generated while driving the plasma etching
apparatus 200 may also be reduced.
[0049] The annular member 220 is connected to an elevating
mechanism 270, and thus is capable of moving up and down together
with the shower head 100. An inner diameter of the annular member
220 is set slightly larger than an outer diameter of the holding
stage 202, and thus a lower portion of the annular member 220 may
descend to surround the holding stage 202. In FIG. 1, the annular
member 220 and the shower head 100 are at descending locations. At
the descending locations, the processing space 212 surrounded by
the holding stage (lower electrode) 202, the shower head (upper
electrode) 100, and the annular member 220 is formed above the
holding stage 202. As such, by delimiting the processing space 212
by using the annular member 220 capable of moving up and down, the
processing space 212 is only formed above the holding stage 202,
thereby suppressing an unnecessary space extending outward in a
horizontal direction from the circumferential portion of the
holding stage 202 from being formed.
[0050] Meanwhile, FIG. 4 shows the annular member 220 and the
shower head 100 at ascending locations. At the ascending locations,
the opening 215 for transferring the semiconductor wafer into and
out of the processing chamber 201 is opened, and at this time, the
semiconductor wafer is transferred into and out of the processing
chamber 201. When the annular member 220 and the shower head 100
are at the descending locations as shown in FIG. 1, the opening 215
is blocked by being covered by the annular member 220.
[0051] In the present embodiment, an electric cylinder 260 is used
as a driving source of the elevating mechanism 270. A multi-axial
driving method, where a plurality of elevating mechanisms 270 is
provided at regular intervals along a circumferential direction of
the processing chamber 201, is used. As such, by using the
multi-axial driving method using the electric cylinder 260,
locations of the annular member 220 and the shower head 100 may be
precisely controlled compared to, for example, when a pneumatic
driving mechanism is used. Also, cooperative control may be
electrically easily performed even by using the multi-axial driving
method.
[0052] As shown in FIG. 1, a driving shaft of the electric cylinder
260 is connected to an elevating shaft 261, and the elevating shaft
261 is provided to penetrate through a fixing shaft 262 having a
cylindrical shape and standing to extend from a bottom portion of
the processing chamber 201 toward an upper portion of the
processing chamber 201. Also, in an airtight sealing portion 263, a
driving part of the elevating shaft 261 is airtightly sealed by,
for example, a double O-ring or the like.
[0053] In the present embodiment, since the shower head 100 is
disposed under a depressurized atmosphere at an inner side of the
lid 205 that airtightly blocks the upper opening of the processing
chamber 201, a pressure difference is added only to a part of the
elevating shaft 261, without having to add a pressure difference
between the depressurized atmosphere and an air atmosphere to the
shower head 100 itself. Accordingly, the shower head 100 is easily
moved up and down with low power, thereby promoting energy saving.
Also, since a mechanical strength of a driving mechanism may be
reduced, apparatus expenses may be reduced.
[0054] A plurality of sheet cables 250 are provided at the annular
member 220 and a ground side of a high-frequency side line of a
bottom of the holding stage 202 to electrically connect
therebetween. The sheet cables 250 are provided at regular
intervals along a circumferential direction of the annular member
220. The sheet cable 250 is formed by coating a surface of a
conductor, having a sheet shape and formed of copper or the like,
with an insulating layer, wherein the conductor near both ends are
exposed to form a connecting portion through which a through hole
for fixing a screw is formed. The sheet cable 250 has a thickness
of, for example, about hundreds of microns, and is thus flexible
and is configured to freely transform according to up-and-down
movements of the annular member 220 and the shower head 100.
[0055] The sheet cable 250 is used with the object of returning a
high frequency wave of the annular member 220 and the shower head
100 constituting the upper electrode, and thus the shower head 100
constituting the upper electrode and the annular member 220 are
electrically connected to each other via the sheet cable 250, and
are electrically connected to the ground side of the high-frequency
side line.
[0056] As such, in the present embodiment, the annular member 220
and the shower head 100 constituting the upper electrode are
electrically connected to the ground side of the high-frequency
side line in a short path via the sheet cable 250 instead of a wall
of a processing chamber or the like. Accordingly, a potential
difference of each portion due to plasma may be suppressed to be
very low.
[0057] Also, the annular member 220 and the shower head 100
constituting the upper electrode move up and down while being
always electrically connected to the ground side of the
high-frequency side line by the sheet cable 250, and thus are not
electrically floated.
[0058] As described above, since the plasma etching apparatus 200
includes the annular member 220 capable of moving up and down, the
processing space 212 may be formed only above the holding stage
202, and thus an unnecessary space extending outward in a
horizontal direction may be suppressed from being formed.
Accordingly, reduction or the like of process gas consumption may
be promoted. Also, since the plasma density in the circumferential
portion of the processing space may be controlled by generating the
ICP plasma in the circumferential portion of the processing space
by using the ICP coil 240 provided in the annular member 220, a
plasma state in the processing space 212 may be more precisely
controlled, thereby performing a uniform process. Also, a distance
between the shower head 100 constituting the upper electrode and
the holding stage 202 may be changed according to process
conditions or the like.
[0059] Further, a physical shape of the processing space 212 is
symmetrical, and thus an asymmetrical shape due to the opening 215
for transferring the semiconductor wafer into and out of the
processing chamber 201 may be suppressed from affecting plasma.
Therefore, a more uniform process may be performed.
[0060] When plasma etching is performed on the semiconductor wafer
by using the plasma etching apparatus 200 having such a
configuration, first, as shown in FIG. 4, the annular member 220
and the shower head 100 are ascended to open the opening 215. At
this time, the semiconductor wafer is transferred into the
processing chamber 201 from the opening 215, is held on the
electrostatic chuck 203, and is electrostatically adsorbed on the
electrostatic chuck 203.
[0061] Next, the annular member 220 and the shower head 100 are
descended to close the opening 215, and the processing space 212 is
formed above the semiconductor wafer. Also, the processing space
212 in the processing chamber 201 is adsorbed to a predetermined
vacuum level via the exhaust holes 13 by using a vacuum pump or the
like.
[0062] Then, a predetermined process gas (etching gas) of a
predetermined flow rate is supplied from a gas supply source (not
shown). The process gas is supplied from the gas ejection holes 11
through the gas flow path 12 of the shower head 100 to the
semiconductor wafer on the holding stage 202 in a shower shape.
[0063] After a pressure in the processing chamber 201 is maintained
to a predetermined pressure, high-frequency power of a
predetermined frequency, for example, 13.56 MHz, is applied to the
holding stage 202. Accordingly, a high-frequency electric field is
generated between the shower head 100 constituting the upper
electrode and the holding stage 202 constituting the lower
electrode, and thus the etching gas is dissociated and plasmatized.
Also, for example, if the plasma density in the circumferential
portion of the processing space 212 is to be increased or the like,
high-frequency power is applied to the ICP coil 240 as occasion
demands so as to generate ICP plasma in the circumferential portion
of the processing space. Then, a predetermined uniform etching
process is performed on the semiconductor wafer by the plasma.
[0064] During the etching process, since the process gas supplied
from the gas ejection holes 11 of the shower head 100 is exhausted
from the plurality of exhaust holes 13 distributedly formed in the
shower head 100, a gas flow from the central portion of the
semiconductor wafer toward the circumferential portion thereof like
when exhaustion is performed from the bottom portion of the
processing chamber 201 does not occur. Accordingly, the process gas
supplied to the semiconductor wafer may be made more uniform.
Accordingly, the plasma state may be uniform, and thus a uniform
etching process may be performed on each portion of the
semiconductor wafer. In other words, in-plane uniformity of a
process may be improved.
[0065] Also, after the predetermined plasma etching process is
ended, the application of the high-frequency power and the supply
of the process gas are stopped, and the semiconductor wafer is
transferred out of the processing chamber 201 in an order opposite
to the order above.
[0066] As described above, according to the plasma etching
apparatus 200 of the present embodiment, the process gas is
supplied and exhausted by using the shower head 100, and thus the
process gas supplied to the semiconductor wafer may be made more
uniform. Accordingly, a uniform etching process may be performed on
each portion of the semiconductor wafer.
[0067] Also, in the plasma etching apparatus 200, since exhaustion
is performed through the exhaust holes 13 formed in the shower head
100, an exhaust path may not be formed around the holding stage 202
or around the shower head 100 like in a conventional apparatus.
Accordingly, it is possible to set a diameter of the processing
chamber 201 closer to an outer diameter of the semiconductor wafer
constituting a substrate to be processed, thereby promoting
miniaturization of the apparatus. Also, since the vacuum pump may
be provided above the processing chamber 201, exhaustion may be
performed from a part closer to the processing space of the
processing chamber 201, and thus a gas may be efficiently
exhausted.
[0068] In addition, an interval between the shower head (upper
electrode) 100 and the holding stage (lower electrode) 202 may be
changed according to a process, and the shower head 100 may be
easily moved up and down with low driving power, and thus energy
saving and apparatus expense reduction may be promoted.
[0069] A plasma processing apparatus according to the present
invention is capable of promoting improvement of in-plane
uniformity of a process compared to a conventional technology,
promoting miniaturization of the apparatus and improvement of
processing efficiency, and easily changing an interval between an
upper electrode and a lower electrode.
[0070] However, the present invention is not limited to the above
embodiments, and various modifications may be made. For example, in
the above embodiment, high-frequency power of one frequency is
supplied to the holding stage (lower electrode), but the present
invention may be equally applied to a type of apparatus in which a
plurality of high-frequency power of different frequencies are
applied to the lower electrode, or the like.
[0071] While this invention has been particularly shown and
described with reference to exemplary embodiments thereof, it will
be understood by those skilled in the art that various changes in
form and details may be made therein without departing from the
spirit and scope of the invention as defined by the appended
claims.
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