U.S. patent application number 15/051801 was filed with the patent office on 2016-09-08 for substrate processing apparatus and substrate processing method.
The applicant listed for this patent is Tokyo Electron Limited. Invention is credited to Shigehiro MIURA.
Application Number | 20160260587 15/051801 |
Document ID | / |
Family ID | 56845478 |
Filed Date | 2016-09-08 |
United States Patent
Application |
20160260587 |
Kind Code |
A1 |
MIURA; Shigehiro |
September 8, 2016 |
SUBSTRATE PROCESSING APPARATUS AND SUBSTRATE PROCESSING METHOD
Abstract
A substrate processing apparatus includes a rotary table
arranged in a vacuum chamber, a first reaction gas supply unit that
supplies a first reaction gas to a surface of the rotary table, a
second reaction gas supply unit that is arranged apart from the
first reaction gas supply unit that supplies a second reaction gas,
which reacts with the first reaction gas, to the rotary table
surface, an activated gas supply unit that is arranged apart from
the first and second reaction gas supply units and includes a
discharge unit that supplies an activated etching gas to the rotary
table surface, and a plurality of purge gas supply units that are
provided near the discharge unit for supplying a purge gas to the
rotary table surface. A flow rate of the purge gas supplied from
each of the purge gas supply units can be independently
controlled.
Inventors: |
MIURA; Shigehiro; (Iwate,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Tokyo Electron Limited |
Tokyo |
|
JP |
|
|
Family ID: |
56845478 |
Appl. No.: |
15/051801 |
Filed: |
February 24, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 21/31116 20130101;
H01J 2237/332 20130101; H01J 37/32715 20130101; H01J 37/32899
20130101; H01J 2237/20214 20130101; H01L 21/68764 20130101; H01L
21/0228 20130101; H01J 37/32009 20130101; H01J 37/32724 20130101;
H01J 2237/334 20130101; H01L 21/30655 20130101; H01J 37/32513
20130101; H01J 37/3244 20130101; H01J 37/32449 20130101 |
International
Class: |
H01J 37/32 20060101
H01J037/32 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 3, 2015 |
JP |
2015-041500 |
Claims
1. A substrate processing apparatus comprising: a vacuum chamber; a
rotary table that is rotatably arranged in the vacuum chamber to
hold a substrate; a first reaction gas supply unit that supplies a
first reaction gas to a surface of the rotary table; a second
reaction gas supply unit that is arranged apart from the first
reaction gas supply unit in a circumferential direction of the
rotary table and supplies a second reaction gas, which reacts with
the first reaction gas, to the surface of the rotary table; an
activated gas supply unit that is arranged apart from the first
reaction gas supply unit and the second reaction gas supply unit in
the circumferential direction of the rotary table, the activated
gas supply unit including a discharge unit having a discharge hole
through which an etching gas that has been activated is supplied to
the surface of the rotary table; and a plurality of purge gas
supply units that are provided near the discharge hole with respect
to the circumferential direction of the rotary table and supply a
purge gas to the surface of the rotary table; wherein a flow rate
of the purge gas supplied from each of the plurality of purge gas
supply units can be independently controlled.
2. The substrate processing apparatus according to claim 1, wherein
the plurality of purge gas supply units are arranged close to each
other along a radial direction of the rotary table.
3. The substrate processing apparatus according to claim 1, wherein
the plurality of purge gas supply units are arranged at an upstream
side of the discharge hole with respect to a rotational direction
of the rotary table.
4. The substrate processing apparatus according to claim 3, wherein
the plurality of purge gas supply units are integrated with the
discharge unit.
5. The substrate processing apparatus according to claim 1, wherein
more discharge holes are arranged at a rotational center side of
the rotary table than at an outer periphery side of the rotary
table.
6. The substrate processing apparatus according to claim 1, wherein
the first reaction gas is a silicon-containing gas; the second
reaction gas is an oxidizing gas; the etching gas is a
fluorine-containing gas; and the purge gas is a hydrogen-containing
gas.
7. The substrate processing apparatus according to claim 1, further
comprising: a control unit that controls the flow rate of the purge
gas supplied from each of the purge gas supply units based on a
distribution of the etching gas supplied to the surface of the
rotary table by the activated gas supply unit.
8. The substrate processing apparatus according to claim 7, wherein
the control unit supplies the first reaction gas and the second
reaction gas from the first reaction gas supply unit and the second
reaction gas supply unit, respectively, and refrains from supplying
the etching gas from the activated gas supply unit when performing
only a film forming process on a surface of the substrate; and the
control unit refrains from supplying the first reaction gas and the
second reaction gas from the first reaction gas supply unit and the
second reaction gas supply unit, and supplies the etching gas and
the purge gas from the activated gas supply unit and the purge gas
supply unit, respectively, when performing only an etching process
on a film that has been formed on the surface of the substrate.
9. A substrate processing method comprising: an etching step of
mounting a substrate on a surface of a rotatory table arranged in a
vacuum chamber and supplying an etching gas into the vacuum chamber
while rotating the rotary table to etch a film formed on a surface
of the substrate; wherein the etching step includes supplying the
etching gas to the surface of the rotary table and supplying a
purge gas from a plurality of purge gas supply units that are
provided near a region where the etching gas is supplied; and
controlling an etching amount of etching the film by independently
varying a flow rate of the purge gas that is supplied from each of
the plurality of purge gas supply units.
10. The substrate processing method according to claim 9, wherein a
flow rate of the purge gas supplied from each of the plurality of
purge gas supply units is varied based on a distribution of the
etching gas supplied to the surface of the rotary table.
11. The substrate processing method according to claim 10, wherein
the flow rate of the purge gas is decreased to increase the etching
amount, and the flow rate of the purge gas increased to decrease
the etching amount.
12. The substrate processing method according to claim 9, further
comprising a film forming step of supplying a first reaction gas
and a second reaction gas, reacts with the first reaction gas, into
the vacuum chamber while rotating the rotary table to form the film
on the surface of the substrate.
13. The substrate processing method according to claim 12, wherein
the film forming step includes a step of supplying the first
reaction gas and the second reaction gas into the vacuum chamber
without supplying the etching gas into the vacuum chamber while
consecutively rotating the rotary table a plurality of times; and
the etching step includes a step of supplying the etching gas and
the purge gas into the vacuum chamber without supplying the first
reaction gas and the second reaction gas into the vacuum chamber
while consecutively rotating the rotary table a plurality of
times.
14. The substrate processing method according to claim 12, wherein
the first reaction gas, the second reaction gas, the etching gas,
and the purge gas are simultaneously supplied into the vacuum
chamber while consecutively rotating the rotary table a plurality
of times; and the film forming step and the etching step are each
performed once during one rotation cycle of the rotary table, and
the rotation cycle is repeated a plurality of times.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention generally relates to a substrate
processing apparatus and a substrate processing method.
[0003] 2. Description of the Related Art
[0004] With the miniaturization of circuit patterns of
semiconductor devices, there is a growing demand for techniques for
reducing the thickness and improving the uniformity of various
films constituting semiconductor devices. In view of such a demand,
the so-called molecular layer deposition (MLD) method or the atom
layer deposition (ALD) method is known as a film forming method
that involves supplying a first reaction gas to a substrate to
cause adsorption of the first reaction gas to the surface of the
substrate, then supplying a second reaction gas to the substrate to
cause a reaction between the first reaction gas that is adsorbed on
the surface of the substrate and the second reaction gas, and
depositing a film that is made of the reaction product on the
substrate (e.g., see Japanese Laid-Open Patent Publication No.
2010-56470).
[0005] According to the above film forming method, the reaction gas
may be adsorbed to the surface of the substrate in a (quasi)
self-saturating manner such that high film thickness
controllability, desirable uniformity, and desirable embedding
characteristics may be achieved.
[0006] However, in view of the miniaturization of circuit patterns,
for example, as the aspect ratio of a space in a line/space pattern
increases in a trench element separation structure, it becomes
increasingly difficult to embed a film in a trench or a space even
when the MLD method or the ALD method is used.
[0007] For example, when embedding a space having a width of about
30 nm in a silicon oxide film, it may be difficult to introduce a
reaction gas to the bottom of such a narrow space, and as a result,
the film thickness at the upper end portions of line side walls
defining the space may increase. Thus, in some cases, a void may be
created in the silicon oxide film having a space embedded by a
film. When such a silicon oxide film is etched in a subsequent
etching process, for example, an opening communicating with the
void may be formed at the upper surface of the silicon oxide film.
In such case, an etching gas (or etching solution) may enter the
void through the opening to cause contamination, or a metal may
enter the void during a metallization process performed thereafter
to create defects, for example.
[0008] The occurrence of such a problem is not limited to the case
of using the MLD method or the ALD method, but may also occur in
the case of using a chemical vapor deposition (CVD) method. For
example, when embedding a film made of conductive material in a
contact hole that is formed in a semiconductor substrate to create
a conductive contact hole (a so-called plug), a void may be formed
in the plug. In this respect, a method of forming a conductive
contact hole while preventing the formation of such a void in the
conductive contact hole is known. For example, when embedding a
conductive material in a contact hole to form a conductive contact
hole, an etch back process may be repeatedly performed to remove
any overhanging portion of the conductive material that is formed
around the upper end of the contact hole (e.g., see Japanese
Laid-Open Patent Publication No. 2003-142484).
[0009] However, according to the method described in Japanese
Laid-Open Patent Publication No. 2003-142484, the process of
forming the conductive material film and the etch back process have
to be performed in different apparatuses. Thus, time is required in
transporting the substrate back and forth between the apparatuses
and stabilizing process conditions in each apparatus such that
throughput cannot be increased.
[0010] Also, a film forming apparatus and a film forming method are
known that may solve the above problems of the method described in
Japanese Laid-Open Patent Publication No. 2003-142484. The film
forming apparatus and the film forming method enable embedding at a
high throughput while reducing the occurrence of voids in a concave
pattern formed on the surface of a substrate. The film forming
apparatus includes a rotary table on which a substrate is mounted,
first and second gas supply units that are capable of supplying
first and second reaction gases for film formation to a substrate
mounting surface of the rotary table, and an activated gas supply
unit that activates and supplies a modification gas for modifying a
reaction product generated by a reaction between the first and
second reaction gases and an etching gas used for etching. The film
formation method involves using such a film forming apparatus to
successively repeat the processes of film formation, modification,
and etching within the same processing chamber through rotation of
the rotary table (e.g., see Japanese Laid-Open Patent Publication
No. 2012-209394).
[0011] However, in the film forming method described in Japanese
Laid-Open Patent Publication No. 2012-209394, the etching amount
distribution in the substrate surface cannot be adequately
controlled, and it is difficult to achieve etching uniformity in
the substrate surface.
SUMMARY OF THE INVENTION
[0012] One aspect of the present invention provides a substrate
processing apparatus that is capable of controlling an etching
amount distribution in within a substrate surface.
[0013] According to one embodiment of the present invention, a
substrate processing apparatus is provided that includes a vacuum
chamber; a rotary table that is rotatably arranged in the vacuum
chamber to hold a substrate; a first reaction gas supply unit that
supplied a first reaction gas to a surface of the rotary table; a
second reaction gas supply unit that is arranged apart from the
first reaction gas supply unit in a circumferential direction of
the rotary table and supplies a second reaction gas, which reacts
with the first reaction gas, to the surface of the rotary table; an
activated gas supply unit that is arranged apart from the first
reaction gas supply unit and the second reaction gas supply unit in
the circumferential direction of the rotary table; and a plurality
of purge gas supply units. The activated gas supply unit includes a
discharge unit having a discharge hole through which an activated
etching gas is supplied to the surface of the rotary table. The
plurality of purge gas supply units are arranged close to the
discharge hole with respect to the circumferential direction of the
rotary table and supply a purge gas to the surface of the rotary
table. A flow rate of the purge gas that is supplied from each of
the plurality of purge gas supply units can be independently
controlled.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] FIG. 1 is a schematic cross-sectional view of a substrate
processing apparatus according to an embodiment of the present
invention;
[0015] FIG. 2 is a schematic plan view of the substrate processing
apparatus;
[0016] FIG. 3 is a partial cross-sectional view illustrating
separation regions in the substrate processing apparatus;
[0017] FIG. 4 is another partial cross-sectional view of the
substrate processing apparatus;
[0018] FIG. 5 is a partial cross-sectional view illustrating a
third process region of the substrate processing apparatus;
[0019] FIG. 6 another schematic plan view of the substrate
processing apparatus;
[0020] FIG. 7 a partial cross-sectional view illustrating purge gas
supply units of the substrate processing apparatus;
[0021] FIGS. 8A-8D are diagrams showing simulation results of a
fluorine volume fraction within a vacuum chamber during an etching
process;
[0022] FIGS. 9A-9C are diagrams showing other simulation results of
the fluorine volume fraction within the vacuum chamber during an
etching process; and
[0023] FIGS. 10A-10D are diagrams showing other simulation results
of the fluorine volume fraction within the vacuum chamber during an
etching process.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0024] In the following, embodiments of the present invention will
be described with reference to the accompanying drawings. Note that
in the following descriptions and the accompanying drawings,
elements having substantially the same functional features are
given the same reference numerals and overlapping descriptions
thereof may be omitted.
[0025] (Substrate Processing Apparatus Configuration)
[0026] In the following, the configuration of a substrate
processing apparatus according to an embodiment of the present
invention is described. FIG. 1 is a schematic cross-sectional view
of the substrate processing apparatus according to the present
embodiment. FIG. 2 is a schematic plan view of the substrate
processing apparatus according to the present embodiment. FIG. 3 is
a partial cross-sectional view illustrating separation regions of
the substrate processing apparatus according to the present
embodiment. FIG. 4 is another partial cross-sectional view of the
substrate processing apparatus according to the present
embodiment.
[0027] As illustrated in FIGS. 1 and 2, the substrate processing
apparatus according to the present embodiment includes a vacuum
chamber 1 having a substantially circular plane shape, and a rotary
table 2 that is arranged within the vacuum chamber 1 such that the
center of the vacuum chamber 1 corresponds to the rotational center
of the rotary table 2.
[0028] The vacuum chamber 1 includes a chamber body 12 having a
cylindrical shape with a bottom, and a ceiling plate 11 that is
detachably arranged on an upper surface of the chamber body 12 and
is sealed airtight to the upper surface via a sealing member 13
such as an O-ring.
[0029] The rotary table 2 has a center portion that is fixed to a
cylindrical core portion 21. The core portion 21 is fixed to an
upper end of a rotary shaft 22 extending in the vertical direction.
The rotary shaft 22 penetrates through a bottom portion 14 of the
vacuum chamber 1 and has a lower end that is attached to a drive
unit 23 for rotating the rotary shaft 22 around a vertical axis.
The rotary shaft 22 and the drive unit 23 are accommodated in a
cylindrical case 20 having an opening formed at its upper face. The
case 20 has a flange portion formed at its upper face that is
attached airtight to a bottom surface of the bottom portion 14 of
the vacuum chamber 1, and in this way, an internal atmosphere
within the case 20 may be maintained airtight from an external
atmosphere of the case 20.
[0030] As illustrated in FIG. 2, a plurality (e.g., 5 in the
illustrated example) of circular concave portions 24 that are
capable of accommodating a plurality of semiconductor wafers
corresponding to substrates (hereinafter referred to as "wafer W")
are arranged along a rotational direction (circumferential
direction) on the surface of the rotary table 2. Note that in FIG.
2, for convenience, the wafer W is illustrated in only one of the
concave portions 24. The concave portion 24 has an inner diameter
that is slightly larger (e.g., larger by 4 mm) than the diameter of
the wafer W (e.g., 300 mm), and a depth that is approximately equal
to the thickness of the wafer W. Thus, when the wafer W is placed
in the concave portion 24, the surface of the wafer W and the
surface of the rotary table 2 (i.e., surface of the region where
the wafer W is not placed) may be substantially flush. Also, a
number (e.g., 3) of through holes (not shown) are formed at a
bottom face of the concave portion 24 such that lift pins (not
shown) for supporting the rear face of the wafer W and lifting the
wafer W may be arranged to penetrate through the through holes.
[0031] Also, as illustrated in FIG. 2, reaction gas nozzles 31 and
32, separation gas nozzles 41 and 42, and an activated gas supply
unit 90 are arranged above the rotary table 2. In the illustrated
example, the activated gas supply unit 90, the separation gas
nozzle 41, the reaction gas nozzle 31, the separation gas nozzle
42, and the reaction gas nozzle 32 are spaced apart along the
circumferential direction of the vacuum chamber 1 in this order as
viewed clockwise (rotational direction of the rotary table 2) from
a transfer port 15 (described below). Note that the reaction gas
nozzle 31 is an example of a first reaction gas supply unit, and
the reaction gas nozzle 32 is an example of a second reaction gas
supply unit.
[0032] The reaction gas nozzles 31 and 32 respectively include a
gas introduction ports 31a and 32a corresponding to base portions
that are fixed to an outer peripheral wall of the chamber body 12.
The reaction gas nozzles 31 and 32 are introduced into the vacuum
chamber 1 from the outer peripheral wall of the vacuum chamber 1.
Also, the reaction gas nozzles 31 and 32 are arranged to extend
parallel with respect to the rotating table 2 along the radial
directions of the chamber body 12.
[0033] The separation gas nozzles 41 and 42 respectively include
gas introduction ports 41a and 42a corresponding to base portions
that are fixed to the outer peripheral wall of the chamber body 12.
The separation gas nozzles 41 and 42 are introduced into the vacuum
chamber 1 from the outer peripheral wall of the vacuum chamber 1.
The separation gas nozzles 41 and 42 are arranged to extend
parallel with respect to the rotary table 2 along the radial
directions of the chamber body 12.
[0034] Note that the activated gas supply unit 90 is described
below.
[0035] The reaction gas nozzle 31 may be made of quartz, for
example, and is connected to a supply source of a Si
(silicon)-containing gas that is used as a first reaction gas via a
pipe and a flow regulator (not shown), for example. The reaction
gas nozzle 32 may be made of quartz, for example, and is connected
to a supply source of an oxidizing gas that is used as a second
reaction gas via a pipe and a flow regulator (not shown), for
example. The separation gas nozzles 41 and 42 are each connected to
supply sources of separation gases via a pipe and a flow rate
regulating valve (not shown), for example.
[0036] An organic amino silane gas may be used as the Si-containing
gas, and O.sub.3 (ozone) gas or O.sub.2 (oxygen) gas may be used as
the oxidizing gas, for example. Also, N.sub.2 (nitrogen) gas and Ar
(argon) gas may be used as the separation gases, for example.
[0037] The reaction gas nozzles 31 and 32 have a plurality of gas
discharge holes 33 that open toward the rotary table 2 (see FIG.
3). The gas discharge holes 33 may be arranged at intervals of 10
mm, for example, along the length direction of the reaction gas
nozzles 31 and 32, for example. A lower region of the reaction gas
nozzle 31 corresponds to a first process region P1 for causing
adsorption of the Si-containing gas to the wafer W. A lower region
of the reaction gas nozzle 32 corresponds to a second process
region P2 for oxidizing the Si-containing gas that has been
adsorbed to the wafer W at the first process region P1.
[0038] Referring to FIG. 2, convex portions 4 protruding toward the
rotary table 2 from bottom face regions of the ceiling plate 11
near the separation gas nozzles 41 and 42 are provided in the
vacuum chamber 1. The convex portions 4 and the separation gas
nozzles 41 and 42 form separation regions D. The convex portion 4
is fan-shaped in planar view and has a top portion that is cut into
a circular arc shape. In the present embodiment, the inner arc of
the convex portion 4 is connected to a protruding portion 5
(described below) and the outer arc of the convex portion 4 is
arranged along an inner peripheral surface of the chamber body 12
of the vacuum chamber 1.
[0039] FIG. 3 is a partial cross-sectional view of the vacuum
chamber 1 along a concentric circle of the rotary table 2 from the
reaction gas nozzle 31 to the reaction gas nozzle 32. As
illustrated in FIG. 3, the vacuum chamber 1 includes a first
ceiling surface 44 corresponding to the bottom face of the convex
portion 4 that is low and flat, and a second ceiling surface 45
that is higher than the first ceiling surface 44 and is arranged at
both sides of the first ceiling surface 44 in the circumferential
direction.
[0040] The first ceiling surface 44 is fan-shaped in planar view
and has a top portion that is cut into a circular arc shape. Also,
as illustrated in FIG. 3, a groove portion 43 extending in a radial
direction is formed at the circumferential direction center of the
convex portion 4, and the separation gas nozzle 42 is accommodated
within this groove portion 43. Note that another groove portion 43
is similarly formed in the other convex portion 4, and the
separation gas nozzle 41 is accommodated within this groove portion
43. Also, the reaction gas nozzles 31 and 32 are arranged in spaces
below the higher second ceiling surface 45. The reaction gas
nozzles 31 and 32 are spaced apart from the second ceiling surface
45 to be arranged close to the wafer W. Note that for convenience
of explanation, the space below the higher second ceiling surface
45 where the reaction gas nozzle 31 is arranged is represented as
"space 481", the space below the higher second ceiling surface 45
where the reaction gas nozzle 32 is arranged is represented as
"space 482" (see FIG. 3).
[0041] The first ceiling surface 44 forms a separation space H
corresponding to a narrow space between the first ceiling surface
44 and the surface of the rotary table 2. The separation space H
can separate the Si-containing gas supplied from the first region
P1 and the oxidizing gas supplied from the second region P2 from
each other. Specifically, when N.sub.2 gas is discharged from the
separation gas nozzle 42, the N.sub.2 gas discharged from the
separation gas nozzle 42 flows toward the space 481 and the space
482 through the separation space H. At this time, because the
N.sub.2 gas flows through the narrow separation space H that has a
smaller volume compared to the spaces 481 and 482, the pressure in
the separation space H can be made higher than the pressure in the
spaces 481 and 482. That is, a pressure barrier may be created
between the spaces 481 and 482. Also, the N.sub.2 gas flowing from
the separation space H into the spaces 481 and 482 act as
counter-flows against the flow of the Si-containing gas from the
first area P1 and the flow of the oxidizing gas from the second
region P2. Thus, the Si-containing gas and the oxidizing gas may be
substantially prevented from flowing into the separation space H.
In this way, the Si-containing gas and the oxidizing gas are
prevented from mixing and reacting with each other in the vacuum
chamber 1.
[0042] Referring to FIG. 2, the protruding portion 5 is arranged
around an outer periphery of the core portion 21 that fixes the
rotary table 2, and the protruding portion 5 is arranged on the
bottom surface of the ceiling plate 11. In the present embodiment,
the protruding portion 5 is connected to a rotational center side
portion of the convex portion 4, and a bottom surface of the
protruding portion 5 is arranged to be flush with the first ceiling
surface 44.
[0043] Note that for convenience of explanation, FIG. 2 illustrates
a cross-section of the chamber body 12 cut along a position that is
higher than the second ceiling surface 45 and lower than the
separation gas nozzles 41 and 42.
[0044] FIG. 1 referred to above is a cross-sectional view of the
substrate processing apparatus along line I-I' of FIG. 2
illustrating a region where the second ceiling surface 45 is
arranged. On the other hand, FIG. 4 is a partial cross-sectional
view of the substrate processing apparatus illustrating a region
where the first ceiling surface 44 is arranged.
[0045] As illustrated in FIG. 4, a bent portion 46 that is bent
into an L-shape to face an outer edge face of the rotary table 2 is
formed at a peripheral portion (portion toward the outer edge of
the vacuum chamber 1) of the fan-shaped convex portion 4. The bent
portion 46, like the convex portion 4, prevents the two reaction
gases from entering the separation space H from both sides of the
separation area D and prevents the two reaction gases from mixing
with each other. The fan-shaped convex portion 4 is arranged at the
ceiling plate 11, and the ceiling plate 11 is arranged to be
detachable from the chamber body 12. Thus, a slight gap is formed
between an outer peripheral face of the bent portion 46 and the
chamber body 12. Note that dimensions of a gap between an inner
peripheral face of the bent portion 46 and an outer edge face of
the rotary table 2, and the gap between the outer peripheral face
of the bent portion 46 and the chamber body 12 may be substantially
the same as the height dimension of the first ceiling surface 44
with respect to the surface of the rotary table 2, for example.
[0046] In the separation region D, an inner peripheral wall of the
chamber body 12 is arranged into a substantially vertical plane
that is in close proximity with the outer peripheral face of the
bent portion 46 as illustrated in FIG. 4. Note, however, that in
regions other than the separation region D, the inner peripheral
wall of the chamber body 12 may have a portion recessed outward
from a region facing the outer edge face of the rotary table 12 to
the bottom portion 14 as illustrated in FIG. 1, for example. In the
following, for convenience of explanation, such a recessed portion
having a rectangular cross section is referred to as "exhaust
region E". More specifically, the exhaust region E that
communicates with the first process region P1 is referred to as
"first exhaust region E1", and the exhaust region E that
communicates with the second process region P2 is referred to as
"second exhaust region E2" as illustrated in FIG. 2. Further, a
first exhaust port 61 and a second exhaust port 62 are respectively
formed at the bottom of the first exhaust region E1 and the second
exhaust region E2. As illustrated in FIG. 1, the first exhaust port
61 and the second exhaust port 62 are each connected to a vacuum
exhaust unit such as a vacuum pump 64 via an exhaust pipe 63. Also,
a pressure regulating unit 65 is arranged at the exhaust pipe
63.
[0047] As illustrated in FIGS. 1 and 4, a heater unit 7 as a
heating unit may be arranged in a space between the rotary table 2
and the bottom portion 14 of the vacuum chamber 1, and a wafer W
arranged on the rotary table 2 may be heated to a predetermined
temperature according to a process recipe via the rotary table 2.
Also, a ring-shaped cover member 71 for preventing gas from
entering a lower region of the rotary table 2 is arranged at a
lower side of a peripheral edge portion of the rotary table 2. The
cover member 71 acts as a partition member for separating the
atmosphere of a region extending from the space above the rotary
table 2 to the exhaust regions E1 and E2 and the atmosphere of a
space where the heater unit 7 is arranged.
[0048] The cover member 71 includes an inner member 71a that faces
an outer edge portion of the rotary table 2 and a portion extending
further outward from this outer edge portion from the lower side,
and an outer member 71b that is arranged between the inner member
71a and an inner wall face of the vacuum chamber 1. In the
separation region D, the outer member 71b is arranged near the bent
portion 46, at the lower side of the bent portion 46, which is
formed at the outer edge portion of the convex portion 4. The inner
member 71a surrounds the entire periphery of the heater unit 7 at
the lower side of the outer edge portion of the rotary table 2 (and
the portion extending slightly outward from the outer edge
portion).
[0049] A protruding portion 12a is formed at a part of the bottom
portion 14 toward the rotational center side of the space where the
heater unit 7 is disposed. The protrusion 12a protrudes upward
toward the core portion 21 at a center portion of the bottom
surface of the rotary table 2. A narrow space is formed between the
protrusion 12a and the core portion 21. Also, a narrow space is
provided between an outer peripheral face of the rotary shaft 22
that penetrates through the bottom portion 14 and an inner
peripheral face of a through hole for the rotary shaft 22. Such
narrow spaces are arranged to be in communication with the case 20.
Further, a purge gas supply pipe 72 for supplying N.sub.2 gas as a
purge gas is arranged at the case 20.
[0050] Also, a plurality of purge gas supply pipes 73 for purging
the space accommodating the heater unit 7 are arranged at the
bottom portion 14 of the vacuum chamber 1 at intervals of a
predetermined angle along the circumferential direction below the
heater unit 7 (only one of the purge gas supply pipes 73 is
illustrated in FIG. 4). Also, a lid member 7a is arranged between
the heater unit 7 and the rotating table 2 in order to prevent gas
from entering the region where the heater unit 7 is located. The
lid member 7a extends in the circumferential direction to cover a
region between an inner wall of the outer member 71b (upper face of
the inner member 71a) and an upper edge portion of the protrusion
12a. The lid member 7a may be made of quartz, for example.
[0051] Also, a separation gas supply pipe 51 is connected to a
center portion of the ceiling plate 11 of the vacuum chamber 1. The
separation gas supply pipe 51 supplies N.sub.2 gas as a separation
gas to a space 52 between the ceiling plate 11 and the core portion
21. The separation gas supplied to the space 52 is discharged
toward the periphery of the rotary table 2 along a wafer mounting
area side surface of the rotary table 2 via a narrow space 50
between the protruding portion 5 and the rotary table 2. The
pressure within the space 50 can be maintained at a higher pressure
than the pressure within the space 481 and the space 482 by the
separation gas. That is, by providing the space 50, the
Si-containing gas supplied to the first process region P1 and the
oxidizing gas supplied to the second process region P2 may be
prevented from passing through a center region C (see FIG. 1) to
mix with each other. In other words, the space 50 (or the center
region C) may have a function similar to that of the separation
space H (or separation region D).
[0052] Further, as illustrated in FIG. 2, the transfer port 15 for
transferring the wafer W corresponding to a substrate between an
external transfer arm 10 and the rotary table 2 is arranged at a
side wall of the vacuum chamber 1. The transfer port 15 may be
opened/closed by a gate valve (not shown). Note that the wafer W
may be transferred back and forth between the concave portion 24
corresponding to the wafer mounting region of the rotary table 2
and the transfer arm 10 when the concave portion 24 is positioned
to face the transfer port 15. Accordingly, lift pins that penetrate
through the concave portion 24 to lift the wafer W from its rear
face and a lift mechanism for the lift pins (not shown) are
arranged at a portion below the rotary table 2 corresponding to a
transfer position for transferring the wafer W.
[0053] In the following, the activated gas supply unit 90 is
described with reference to FIGS. 2 and 5-7. FIG. 5 is a partial
cross-sectional view illustrating a third process region P3 of the
substrate processing apparatus according to the present embodiment.
FIG. 6 is a schematic plan view of the substrate processing
apparatus according to the present embodiment. FIG. 7 is a partial
cross-sectional view illustrating purge gas supply units 96 of the
substrate processing apparatus according to the present embodiment.
Note that FIG. 6 illustrates a state in which the plasma generation
unit 91 and the etching gas supply unit 92 are removed from the
substrate processing apparatus illustrated in FIG. 2. Also, FIG. 7
illustrates a cross-section of FIG. 6 along line J-J'.
[0054] The activated gas supply unit 90 supplies an activated
etching gas to a film formed on the wafer W to etch the film. As
illustrated in FIGS. 2 and 5, the activated gas supply unit 90
includes a plasma generation unit 91, an etching gas supply pipe
92, a shower head unit 93, and a pipe 94. Note that the shower head
unit 93 is an example of a discharge unit.
[0055] The plasma generation unit 91 activates an etching gas
supplied from the etching gas supply pipe 92 using a plasma source.
The plasma source is not particularly limited as long as it is
capable of activating the fluorine-containing gas to generate F
(fluorine) radicals. For example, an inductively coupled plasma
(ICP), a capacitively coupled plasma (CCP), or a surface wave
plasma (SWP) may be used as the plasma source.
[0056] The etching gas supply pipe 92 has one end that is connected
to the plasma generation unit 91 and is configured to supply the
etching gas to the plasma generation unit 91. The other end of the
etching gas supply pipe 92 may be connected to an etching gas
supply source that stores the etching gas via an on-off valve and a
flow regulator, for example. Note that a gas that is capable of
etching the film formed on the wafer W may be used as the etching
gas. Specifically, for example, fluorine-containing gases including
hydrofluorocarbons such as CHF.sub.3 (trifluoromethane),
fluorocarbons such as CF.sub.4 (carbon tetrafluoride) for etching a
silicon oxide film may be used. Further, gases such as Ar gas,
O.sub.2 gas, and/or H.sub.2 (hydrogen) gas may be added to these
fluorine-containing gases at appropriate amounts, for example.
[0057] The shower head unit 93 is connected to the plasma
generation unit 91 via the pipe 94. The shower head unit 93
supplies the etching gas that has been activated by the plasma
generation unit 91 into the vacuum chamber 1. The shower head unit
93 is fan-shaped in planar view and is pressed downward along the
circumferential direction by a press member 95 that is formed along
the outer edge of the fan shape. The press member 95 is fixed to
the ceiling plate 11 by a bolt or the like (not shown), and in this
way, the internal atmosphere of the vacuum chamber 1 may be
maintained airtight. The distance between a bottom face of the
shower head unit 93 when it is secured to the ceiling plate 11 and
a surface of the rotary table 2 may be arranged to be about 0.5 mm
to 5 mm, for example. A lower region of the shower head unit 93
corresponds to the third process region P3 for etching a silicon
oxide film, for example. In this way, F radicals contained in the
activated etching gas that is supplied into the vacuum chamber 1
via the shower head unit 93 may efficiently react with the film
formed on the wafer W.
[0058] A plurality of gas discharge holes 93a are arranged at the
shower head unit 93. In view of the difference in angular velocity
of the rotary table 2, a smaller number of the gas discharge holes
93a are arranged at a rotational center side of the shower head
unit 93, and a larger number of the gas discharge holes 93a are
arranged at an outer periphery side of the shower head unit 93. The
total number of the gas discharge holes 93a may be several tens to
several hundreds, for example. Also, the diameter of the plurality
of gas discharge holes 93a may be about 0.5 mm to 3 mm, for
example. The activated fluorine-containing gas supplied to the
shower head unit 93 may be supplied to the space between the rotary
table 2 and the shower head unit 93 via the gas discharge holes
93a.
[0059] The pipe 94 connects the plasma generation unit 91 and the
shower head unit 93.
[0060] Also, as illustrated in FIGS. 6 and 7, three purge gas
supply units 96 (96a, 96b, 96c) are arranged in front of the gas
discharge holes 93a with respect to the circumferential direction
of the vacuum chamber 1 (upstream side with respect to the
rotational direction of the rotary table 2). The purge gas supply
units 96a-96c are arranged close to the gas discharge holes 93a to
form integral parts of the shower head unit 93.
[0061] The purge gas supply units 96a-96c are arranged along a
radial direction of the chamber body 12 so as to extend
horizontally with respect to the rotary table 2, and a purge gas is
supplied to a space between the rotary table 2 and the shower head
unit 93. Each of the purge gas supply units 96a-96c may be
connected to an open/close valve and a flow regulator, for example,
such that supply flow rate of the purge gas may be independently
controlled at each of the purge gas supply units 96a-96c. The flow
rate of the purge gas supplied from each of the purge gas supply
units 96 is controlled based on the distribution of the etching gas
supplied to the surface of the rotary table 2 by the activated gas
supply unit 90.
[0062] The purge gas supply unit 96a is arranged more toward the
rotational center side than the purge gas supply unit 96b along the
radial direction of the chamber body 12. The purge gas supply unit
96b is arranged more toward the rotational center side than the
purge gas supply unit 96c along the radial direction of the chamber
body 12.
[0063] By supplying the purge gas from the purge gas supply units
96a-96c, the volume fraction of fluorine contained in the etching
gas supplied from the gas discharge holes 93a to the space between
the rotary table 2 and the shower head unit 93 may be reduced. Note
that gases such as Ar gas or a gas mixture of Ar gas and H.sub.2
gas (hereinafter referred to as "Ar/H.sub.2 gas") may be used as
the purge gas, but Ar/H.sub.2 gas is preferably used as the purge
gas. In this way, F radicals react with the H.sub.2 gas to generate
HF (hydrogen fluoride) such that the amount of F radicals is
reduced. That is, the concentration of F radicals may be
controlled.
[0064] Also, as illustrated in FIGS. 6 and 7, three purge gas
supply units 96 (96d, 96e, 96f) are arranged behind the gas
discharge holes 93a with respect to the circumferential direction
of the vacuum chamber 1 (downstream side with respect to the
rotational direction of the rotary table 2). The purge gas supply
units 96d-96f are likewise arranged close to the gas discharge
holes 93a to form integral parts of the shower head unit 93.
[0065] The purge gas supply units 96d-96f are arranged along a
radial direction of the chamber body 12 to extend horizontally with
respect to the rotary table 2, and a purge gas is supplied to a
space between the rotary table 2 and the shower head portion 93.
Each of the purge gas supply units 96d-96f may be connected to an
open/close valve and a flow regulator, for example, such that the
supply flow rate of the purge gas may be independently controlled
at each of the purge gas supply units 96d-96f.
[0066] The purge gas supply unit 96d is arranged more toward the
rotational center side than the purge gas supply unit 96e along the
radial direction of the chamber body 12. The purge gas supply unit
96e is arranged more toward the rotational center side than the
purge gas supply unit 96f in the radial direction of the chamber
body 12.
[0067] By supplying the purge gas from the purge gas supply units
96d-96f, the volume fraction of fluorine contained in the etching
gas supplied from the gas discharge holes 93a to the space between
the rotary table 2 and the shower head unit 93 may be reduced. Note
that the same gas as that supplied by the purge gas supply units
96a-96c such as Ar gas or preferably Ar/H.sub.2 gas may be used as
the purge gas supplied by the purge gas supply units 96d-96f, for
example.
[0068] Note that in FIG. 6, three purge gas supply units 96 are
arranged in front of the gas discharge holes 93a and three purge
gas supply units 96 are arranged behind the gas discharge holes 93a
with respect to the circumferential direction of the vacuum chamber
1. However, the present invention is not limited to such an
arrangement. For example, all of the purge gas supply units 96 may
be arranged only in front of the gas discharge holes 93a with
respect to the circumferential direction of the vacuum chamber 1,
or all of the purge gas supply units 96 may be arranged only behind
the gas discharge holes 93a with respect to the circumferential
direction. Also, the number of the purge gas supply units 96
arranged at the shower head unit 93 may be any number greater than
or equal to two.
[0069] Also, the substrate processing apparatus of the present
embodiment includes a control unit 100 configured by a computer
that performs overall control operations of the substrate
processing apparatus. The control unit 100 includes a memory that
stores a program for causing the substrate processing apparatus to
implement a substrate processing method according to an embodiment
of the present invention (described below) under control of the
control unit 100. The program includes a set of steps set for
performing operations of the substrate processing apparatus
(described below) and may be installed in the control unit 100 from
a storage unit 101 such as a hard disk, a compact disk, an optical
disk, a memory card, a flexible disk, or some other type of
computer-readable storage medium.
[0070] (Substrate Processing Method)
[0071] In the following, an exemplary substrate processing method
using the substrate processing apparatus according to the
above-described embodiment is described. Hereinafter, a method of
forming a SiO.sub.2 film in a via hole corresponding to an example
of a concave pattern that is formed in the wafer W is described as
an example. Also, note that in the example described below, it is
assumed that a Si-containing gas is used as the first reaction gas,
an oxidizing gas is used as the second reaction gas, and a gas
mixture of CF.sub.4, Ar gas, O.sub.2 gas, and H.sub.2 gas
(hereinafter referred to as "CF.sub.4/Ar/O.sub.2/H.sub.2 gas") is
used as the etching gas.
[0072] First, a gate valve (not shown) is opened, and a wafer W is
transferred from the exterior by the transfer arm 10 via the
transfer port 15 to be placed within one of the concave portions 24
of the rotary table 2 as illustrated in FIG. 2. The transfer of the
wafer W may be accomplished by lifting the lift pins (not shown)
from the bottom side of the vacuum chamber 1 via the through holes
that are formed at the bottom face of the concave portion 24 when
the concave portion 24 comes to a halt at a position facing the
transfer port 15. Such a transfer of the wafer W may be performed
with respect to each of the five concave portions 24 of the rotary
table 2 by intermittently rotating the rotary table 2 to place a
wafer W in each of the concave portions 24, for example.
[0073] Then, the gate valve is closed, and air is drawn out of the
interior of the vacuum chamber 1 by the vacuum pump 64. Then,
N.sub.2 gas as a separation gas is discharged at a predetermined
flow rate from the separation gas nozzles 41 and 42, and N.sub.2
gas is discharged at a predetermined flow rate from the separation
gas supply pipe 51 and the purge gas supply pipes 72 and 73. In
turn, the pressure regulating unit 65 adjusts the pressure within
the vacuum chamber 1 to a preset processing pressure. Then, the
heater unit 7 heats the wafers W up to 450.degree. C., for example,
while the rotary table 2 is rotated clockwise at a rotational speed
of 60 rpm, for example.
[0074] Then, a film forming process is performed. In the film
forming process, a Si-containing gas is supplied from the reaction
gas nozzle 31, and an oxidizing gas is supplied from the reaction
gas nozzle 32. Note that in this process, no gas is supplied from
the activated gas supply unit 90.
[0075] When one of the wafers W passes the first process region P1,
the Si-containing gas as a source gas that is supplied from the
reaction gas nozzle 31 is adsorbed to the surface of the wafer W.
Then, as the rotary table 2 is rotated, the wafer W having the
Si-containing gas adsorbed to its surface passes the separation
region D including the separation gas nozzle 42 where the wafer W
is purged. Thereafter, the wafer W enters the second process region
P2. In the second process region P2, the oxidizing gas is supplied
from the reaction gas nozzle 32, and Si components contained in the
Si-containing gas is oxidized by the oxidizing gas. As a result,
SiO.sub.2 corresponding to a reaction product of the oxidization is
deposited on the surface of the wafer W.
[0076] The wafer W that has passed the second process region P2
passes the separation region D including the separation gas nozzle
41 where the wafer W is purged. Then, the wafer W enters the first
process region P1 once again. Then, the Si-containing gas that is
supplied from the reaction gas nozzle 31 is adsorbed to the surface
of the wafer W.
[0077] As described above, in the film forming process, the rotary
table 2 is consecutively rotated a plurality of times while
supplying the first reaction gas and the second reaction gas into
the vacuum chamber 1 but without supplying a fluorine-containing
gas into the vacuum chamber 1. In this way, SiO.sub.2 corresponding
to the reaction product may be deposited on the surface of the
wafer W and a SiO.sub.2 film (silicon oxide film) may be formed on
the wafer W surface.
[0078] Also, if necessary or desired, after the SiO.sub.2 film has
been formed to a predetermined thickness, the supply of the
Si-containing gas from the reaction gas nozzle 31 may be stopped
but the oxidizing gas may continuously be supplied from the
reaction gas nozzle 32 while rotation of the rotary table 2 is
continued. In this way, a modification process may be performed on
the SiO.sub.2 film.
[0079] By executing the film forming process as described above,
the SiO.sub.2 film may be formed in a via hole corresponding to one
example of a concave pattern. The SiO.sub.2 film that is first
formed in the via hole may have a cross-sectional shape
substantially corresponding to the concave shape of the via
hole.
[0080] Then, an etching process is performed. In the etching
process, the SiO.sub.2 film is etched to have a V-shaped
cross-sectional shape. In the following, specific process steps of
the etching process are described.
[0081] As shown in FIG. 2, the supply of the Si-containing gas and
the oxidizing gas from the reaction gas nozzles 31 and 32 are
stopped, and N.sub.2 gas as a purge gas is supplied. The
temperature of the rotary table 2 is set to a temperature of about
600.degree. C., for example, that is suitable for etching. The
rotation speed of the rotary table 2 may be set to 60 rpm, for
example. In such a state, the CF.sub.4/Ar/O.sub.2/H.sub.2 gas is
supplied from the shower head unit 93 of the activated gas supply
unit 90, Ar gas is supplied from the hydrogen-containing gas supply
unit 96 at a preset flow rate, for example, and the etching process
is started.
[0082] Note that at this time, the rotary table 2 is rotated at a
relatively low speed such that the SiO.sub.2 film may be etched to
have a V-shaped cross-sectional shape. By etching the S102 film in
the via hole into a V-shape, a hole having a wide opening at its
top portion may be formed in the SiO.sub.2 film, and in this way,
when embedding a SiO.sub.2 film in the hole in a subsequent film
forming process, the SiO.sub.2 may reach the bottom of the hole
such that bottom-up characteristics may be improved and void
generation may be prevented in the film forming process.
[0083] Note that when etching the SiO2 film in the etching process,
the etching amount may vary depending on the etching location,
namely, from the rotational center side to the outer periphery side
of the wafer W surface. When such a variation in the etching amount
is created in the wafer W surface, it is difficult to secure
etching uniformity in the wafer W surface.
[0084] In view of the above, the substrate processing apparatus
according to the present embodiment has a plurality of purge gas
supply units 96 arranged on at least one side of the gas discharge
holes 93a with respect to the circumferential direction of the
vacuum chamber 1. By arranging the purge gas supply units 96 in
this manner, Ar gas may be supplied to the space between the rotary
table 2 and the shower head unit 93 at a preset flow rate, for
example. Also, the flow rate of the Ar gas supplied from each of
the plurality of purge gas supply units 96 may be independently
controlled such that the etching amount distribution within the
wafer W surface may be adjusted.
[0085] Specifically, when the etching amount at the rotational
center side of the wafer W surface is large, the flow rate of the
Ar gas supplied from the purge gas supply unit 96a may be adjusted
to be greater than the flow rate of the Ar gas supplied from the
purge gas supply units 96b and 96c. Note that in the above case,
the flow rate of the Ar gas supplied from the purge gas supply unit
96d may be adjusted to be greater than the flow rate of the Ar gas
supplied from the purge gas supply units 96e and 96f instead.
Moreover, both the Ar gas flow rates of the purge gas supply units
96a and 96d may be adjusted to be greater than the Ar gas flow
rates of the other purge gas supply units 96.
[0086] Also, when the etching amount at the outer periphery side of
the wafer W surface is large, the flow rate of the Ar gas supplied
from the purge gas supply unit 96c may be adjusted to be greater
than the flow rate of the Ar gas supplied from the purge gas supply
units 96a and 96b. Note that in the above case, the flow rate of
the Ar gas supplied from the purge gas supply unit 96f may be
adjusted to be greater than the flow rate of the Ar gas supplied
from the purge gas supply units 96d and 96e instead. Further, both
the Ar gas flow rates of the purge gas supply units 96c and 96f may
be adjusted to be greater than the other purge gas supply units
96.
[0087] Note that the flow rate of the Ar gas supplied from each of
the purge gas supply units 96 may be controlled by the control unit
100 to flow at preset flow rate, or the flow rate may be controlled
by an operator of the substrate processing apparatus, for
example.
[0088] As described above, in the etching process, the rotary table
2 is rotated consecutively a plurality of times while supplying the
etching gas and the purge gas into the vacuum chamber 1 but without
supplying the first reaction gas and the second reaction gas into
the vacuum chamber 1. In this way, the SiO.sub.2 film may be
etched.
[0089] Then, the above-mentioned film forming process is performed
again. In this film forming process, another SiO.sub.2 film is
formed on the SiO.sub.2 film that has been etched into a V-shape in
the above etching process to increase the film thickness. Because a
film is formed on the SiO.sub.2 film that has been etched into a
V-shape, the opening of the hole in the SiO.sub.2 film may be
prevented from closing during film formation such that the film may
be formed from the bottom portion of the SiO.sub.2 film.
[0090] Then, the above-mentioned etching process is performed
again. In the etching process, the SiO.sub.2 film is etched into a
V-shape.
[0091] The above-described film forming process and etching process
may be alternately performed as many times as necessary to embed
the via hole while preventing the generation of a void in the
SiO.sub.2 film. The number of times these processes are repeated
may be adjusted to a suitable number according to the shape of the
concave pattern (e.g. via hole) such as the aspect ratio of the
concave pattern. For example, the number of repetitions may be
increased as the aspect ratio is increased. Also, the number of
repetitions is expected to be greater when embedding a via hole as
compared to embedding a trench, for example.
[0092] Note that in the present embodiment, the film forming
process and the etching process are repeatedly performed to embed a
film in a concave pattern that is formed in the surface of the
wafer W. However, the present invention is not limited thereto.
[0093] For example, a wafer W already having a film formed on its
surface may be transferred and loaded in the substrate processing
apparatus, and only the etching process may be performed on the
wafer W.
[0094] Also, in some examples, the first reaction gas, the second
reaction gas, the etching gas, and the purge gas may be
simultaneously supplied into the vacuum chamber 1 while
consecutively rotating the rotary table 2 a plurality of times, and
the film forming process and the etching process may each be
performed once during one rotation cycle of the rotary table 2.
Further, in some examples, a cycle of performing each of the film
forming process and the etching process once may be repeated a
plurality of times.
EXAMPLES
[0095] In the following, results of simulations and experiments
conducted using the substrate processing apparatus according to the
above-described embodiment are described.
[0096] FIGS. 8A-8D are diagrams showing simulation results of the
fluorine volume fraction within the vacuum chamber 1 when CF.sub.4
gas, Ar gas, O.sub.2 gas, and H.sub.2 gas (hereinafter referred to
as "CF.sub.4/Ar/O.sub.2/H.sub.2 gas") are supplied from the
activated gas supply unit 90, and Ar gas is supplied from the purge
gas supply units 96 (96a, 96b, 96c) that are arranged in front of
the activated gas supply unit 90 with respect to the
circumferential direction of the vacuum chamber 1.
[0097] The following simulation conditions were used in the present
experiment. That is, the pressure of the vacuum chamber 1 was set
to 2 Torr, and the temperature of the rotary table 2 was set to
600.degree. C., and the rotational speed of the rotary table 2 was
set to 60 rpm. Also, the Ar gas flow rate of the separation gas
supply pipe 51 was set to 0.5 slm, and the Ar gas flow rate of the
purge gas supply pipe 73 was set to 1 slm. Also, at the etching gas
supply pipe 92, the CF.sub.4 gas flow rate was set to 10 sccm, the
Ar gas flow rate was set to 4 slm, the O.sub.2 gas flow rate was
set to 30 sccm, and the H.sub.2 gas flow rate was set to 20
sccm.
[0098] Under the above conditions, the flow rate of the Ar gas
supplied from the purge gas supply units 96a, 96b, and 96c were
varyingly set to 100 sccm or 300 sccm, and the fluorine volume
fraction within the vacuum chamber 1 was simulated.
[0099] FIG. 8A is a diagram showing the simulation result in the
case where the flow rates of the Ar gas supplied from the purge gas
supply units 96a, 96b, and 96c were all set to 100 sccm. FIG. 8B is
a diagram showing the simulation result in the case where the flow
rate of the Ar gas supplied from the purge gas supply unit 96a was
set to 300 sccm, and the flow rates of the Ar gas supplied from the
purge gas supply units 96b and 96c were set to 100 sccm. FIG. 8C is
a diagram showing the simulation result in the case where the flow
rate of the Ar gas supplied from the purge gas supply unit 96b was
set to 300 sccm, and the flow rates of the Ar gas supplied from the
purge gas supply units 96a and 96c were set to 100 sccm. FIG. 8D is
a diagram showing the simulation result in the case where the flow
rate of the Ar gas supplied from the purge gas supply unit 96c was
set to 300 sccm, and the flow rates of the Ar gas supplied from the
purge gas supply units 96a and 96b were set to 100 sccm.
[0100] In FIGS. 8A-8D, region Z1 represents a region with the
highest fluorine volume fraction. Further, the fluorine volume
fraction being represented decreases from region Z2 to region Z3,
from region Z3 to region Z4, from region Z4 to region Z5, from
region Z5 to region Z6, from region Z6 to region Z7, from region Z7
to region Z8, from region Z8 to region Z9, and from region Z9 to
region Z10.
[0101] Referring to FIGS. 8A-8D, it can be appreciated that in
regions located in front of the purge gas supply units 96 with
respect to the circumferential direction, the fluorine volume
fraction is lower in the case where the Ar gas flow rate is set to
300 sccm as compared to the case where the Ar gas flow rate is set
to 100 sccm. More specifically, in FIGS. 8B-8D as compared to FIG.
8A, the area of region Z4 is smaller and the areas of regions Z5
and Z6 are larger in the region located in front of the purge gas
supply unit 96 that has been set up to supply the Ar gas at the
flow rate of 300 sccm. That is, by increasing the Ar gas flow rate
of one or more of the purge gas supply units 96, the fluorine
volume fraction may be decreased in the region located in front of
the purge gas supply unit 96 that has been set up to supply the Ar
gas at the increased flow rate. As a result, the silicon oxide film
etching amount in the corresponding region may be reduced.
[0102] FIGS. 9A-9C are diagrams similar to FIGS. 8A-8D showing
simulation results of the fluorine volume fraction within the
vacuum chamber 1 when the CF.sub.4/Ar/O.sub.2/H.sub.2 gas is
supplied from the activated gas supply unit 90, and Ar gas is
supplied from the purge gas supply units 96 (96a, 96b, 96c) that
are arranged in front of the activated gas supply unit 90 with
respect to the circumferential direction of the vacuum chamber 1.
Note that in FIGS. 9A-9C, simulation conditions similar to those of
FIGS. 8A-8D were used, but the flow rates of Ar gas supplied from
the purge gas supply units 96a-96c were varyingly set to 100 sccm
or 1000 sccm, and the fluorine volume fraction within the vacuum
chamber 1 was simulated under these conditions.
[0103] FIG. 9A is a diagram showing the simulation result in the
case where the flow rate of the Ar gas supplied from the purge gas
supply unit 96a was set to 1000 sccm, and the flow rates of the Ar
gas supplied from the purge gas supply units 96b and 96c were set
to 100 sccm. FIG. 9B is a diagram showing the simulation result in
the case where the flow rate of the Ar gas supplied from the purge
gas supply unit 96b was set to 1000 sccm, and the flow rates of the
Ar gas supplied from the purge gas supply units 96a and 96c were
set to 100 sccm. FIG. 9C is a diagram showing the simulation result
in the case where the flow rate of the Ar gas supplied from the
purge gas supply unit 96c was set to 1000 sccm, and the flow rates
of the Ar gas supplied from the purge gas supply units 96a and 96b
were set to 100 sccm.
[0104] In FIGS. 9A-9C, region Z1 represents a region where the
fluorine volume fraction is the highest. Further, the fluorine
volume fraction being represented decreases from region Z2 to
region Z3, from region Z3 to region Z4, from region Z4 to region
Z5, from region Z5 to region Z6, from region Z6 to region Z7, from
region Z7 to region Z8, from region Z8 to region Z9, and from
region Z9 to region Z10.
[0105] Referring to FIG. 8A and FIGS. 9A-9C, it can be appreciated
that in the regions located in front of the purge gas supply units
96 with respect to the circumferential direction, the fluorine
volume fraction is lower in the case where the Ar gas flow rate is
set to 1000 sccm as compared to the case where the Ar gas flow rate
is set to 100 sccm. More specifically, in FIGS. 9A-9C as compared
to FIG. 8A, the area of region Z4 is smaller and the areas of
regions Z5 and Z6 are larger in the region located in front of the
purge gas supply unit 96 that has been set up to supply the Ar gas
at the flow rate of 1000 sccm. That is, by increasing the Ar gas
flow rate of one or more of the purge gas supply units 96, the
fluorine volume fraction may be decreased in the region located in
front of the purge gas supply unit 96 that has been set up to
supply the Ar gas at the increased flow rate. As a result, the
silicon oxide film etching amount in the corresponding region may
be reduced. Further, by increasing the Ar gas flow rate from 300
sccm to 1000 sccm, the fluorine volume fraction may be further
decreased as compared to the case where the Ar gas flow rate is set
to 300 sccm.
[0106] FIGS. 10A-10D are diagrams showing simulation results of the
fluorine volume fraction within the vacuum chamber 1 when the
CF.sub.4/Ar/O.sub.2/H.sub.2 gas is supplied from the activated gas
supply unit 90, and Ar gas is supplied from the purge gas supply
units 96 (96d, 96e, 96f) that are arranged behind the activated gas
supply unit 90 with respect to the circumferential direction of the
vacuum chamber 1. Note that in FIGS. 10A-10D, the flow rates of Ar
gas supplied from the purge gas supply units 96d-96f were varyingly
set to 100 sccm or 300 sccm under simulation conditions similar to
those of FIGS. 8A-8D, and the fluorine volume fraction within the
vacuum chamber 1 was simulated under these conditions.
[0107] FIG. 10A is a diagram showing the simulation result in the
case where the Ar gas flow rates of the purge gas supply units
96d-96f were all set to 100 scm. FIG. 10B is a diagram showing the
simulation result in the case where the flow rate of the Ar gas
supplied from the purge gas supply unit 96d was set to 300 sccm,
and the flow rates of the Ar gas supplied from the purge gas supply
units 96e and 96f were set to 100 sccm. FIG. 10C is a diagram
showing the simulation result in the case where the flow rate of
the Ar gas supplied from the purge gas supply unit 96e was set to
300 sccm, and the flow rates of the Ar gas supplied from the purge
gas supply units 96d and 96f were set to 100 sccm. FIG. 10D is a
diagram showing the simulation result in the case where the flow
rate of the Ar gas supplied from the purge gas supply unit 96f was
set to 300 sccm, and the flow rates of the Ar gas supplied from the
purge gas supply units 96d and 96e were set to 100 sccm.
[0108] In FIGS. 10A-10D, region Z1 represents a region where the
fluorine volume fraction is the highest. Further, the fluorine
volume fraction being represented decreases from region Z2 to
region Z3, from region Z3 to region Z4, from region Z4 to region
Z5, from region Z5 to region Z6, from region Z6 to region Z7, from
region Z7 to region Z8, from region Z8 to region Z9, and from
region Z9 to region Z10.
[0109] Referring to FIGS. 10A-10D, it can be appreciated that in
regions located behind the purge gas supply units 96 with respect
to the circumferential direction, the fluorine volume fraction is
lower in the case where the Ar gas flow rate is set to 300 sccm as
compared to the case where the Ar gas flow rate is set to 100 sccm.
More specifically, in FIGS. 10B-10D as compared to FIG. 10A, the
area of region Z4 is smaller and the areas of regions Z5 and Z6 are
larger in the region located behind the purge gas supply unit 96
that has been set up to supply the Ar gas at the flow rate of 300
sccm. That is, by increasing the Ar gas flow rate of one or more of
the purge gas supply units 96, the fluorine volume fraction may be
decreased in the region located behind the purge gas supply unit 96
that has been set up to supply the Ar gas at the increased flow
rate. As a result, the silicon oxide film etching amount in the
corresponding region may be reduced. Further, by arranging the
purge gas supply units 96 behind the activated gas supply unit 90
with respect to the circumferential direction, Ar gas that is
supplied from the purge gas supply unit 96 that is arranged at a
center with respect to the radial direction of the vacuum chamber 1
may be prevented from flowing toward the outer periphery side with
respect to the radial direction of the vacuum chamber 1. In this
way, controllability of the fluorine volume fraction may be
improved.
[0110] As described above, according to an aspect of the substrate
processing apparatus and the substrate processing method of the
present embodiment, the etching amount distribution in a substrate
surface may be controlled.
[0111] Although a substrate processing apparatus and a substrate
processing method according to the present invention have been
described above with respect to certain illustrative embodiments,
the present invention is not limited to the above embodiments, and
various variations and modifications may be made within the scope
of the present invention.
[0112] For example, in the above descriptions, an embodiment in
which the plasma generation unit 91 of the activated gas supply
unit 90 is arranged above the shower head unit 93 via the pipe 94
is illustrated. However, the position of the plasma generation unit
91 is not particularly limited as long as it is arranged at a
suitable position such that a fluorine-containing gas may be
activated and supplied to a film that is formed on a wafer W. For
example, the plasma generation unit 91 may be arranged inside the
shower head unit 93 or below the shower head 93.
[0113] The present application is based on and claims the benefit
of priority to Japanese Patent Application No. 2015-041500 filed on
Mar. 3, 2015, the entire contents of which are hereby incorporated
by reference.
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