U.S. patent application number 14/676890 was filed with the patent office on 2015-10-15 for substrate processing apparatus and substrate processing method.
The applicant listed for this patent is TOKYO ELECTRON LIMITED. Invention is credited to Takayuki KARAKAWA.
Application Number | 20150292087 14/676890 |
Document ID | / |
Family ID | 54264615 |
Filed Date | 2015-10-15 |
United States Patent
Application |
20150292087 |
Kind Code |
A1 |
KARAKAWA; Takayuki |
October 15, 2015 |
Substrate Processing Apparatus and Substrate Processing Method
Abstract
A substrate processing apparatus includes: a mounting stand
provided with a substrate mounting region in which a workpiece
substrate is mounted; a process vessel for defining a process
chamber including a first region and a second region through which
the substrate mounting region passes in order; a precursor gas
supply unit for supplying a precursor gas to the first region; a
process gas supply unit for supplying a first gas or a second gas
differing from the first gas to the second region; at least one
plasma generating unit for generating plasma of the first gas or
the second gas in the second region; and a control unit for
executing a repetition control of repeating a first operation for
supplying the first gas to the second region for a first time and a
second operation for supplying the second gas to the second region
for a second time.
Inventors: |
KARAKAWA; Takayuki;
(Kurokawa-gun, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
TOKYO ELECTRON LIMITED |
Tokyo |
|
JP |
|
|
Family ID: |
54264615 |
Appl. No.: |
14/676890 |
Filed: |
April 2, 2015 |
Current U.S.
Class: |
427/569 ;
118/702; 118/704 |
Current CPC
Class: |
H01J 37/32779 20130101;
C23C 16/45536 20130101; C23C 16/4404 20130101; C23C 16/511
20130101; C23C 16/45551 20130101; H01J 37/32449 20130101; C23C
16/4584 20130101 |
International
Class: |
C23C 16/455 20060101
C23C016/455; C23C 16/511 20060101 C23C016/511; C23C 16/458 20060101
C23C016/458; C23C 16/52 20060101 C23C016/52; C23C 16/50 20060101
C23C016/50 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 9, 2014 |
JP |
2014080532 |
Claims
1. A substrate processing apparatus, comprising: a mounting stand
provided with a substrate mounting region in which a workpiece
substrate is mounted, the mounting stand being installed so as to
rotate about an axis such that the substrate mounting region is
moved in a circumferential direction; a process vessel configured
to define a process chamber which accommodates the mounting stand
therein, the process chamber including a first region and a second
region through which the substrate mounting region moving about the
axis in the circumferential direction upon rotation of the mounting
stand passes in order; a precursor gas supply unit configured to
supply a precursor gas to the first region; a process gas supply
unit configured to supply a first gas or a second gas differing
from the first gas to the second region; at least one plasma
generating unit configured to generate plasma of the first gas or
the second gas in the second region; and a control unit configured
to execute a repetition control of repeating a first operation for
supplying the first gas to the second region for a first time and a
second operation for supplying the second gas to the second region
for a second time.
2. The apparatus of claim 1, wherein the at least one plasma
generating unit is at least two plasma generating units, wherein
each of the at least two plasma generating units includes said
process gas supply unit and each process gas supply unit is
connected to a common process gas supply source.
3. The apparatus of claim 1, wherein the total sum of the first
time and the second time differs in length from the time required
for the mounting stand to make one revolution about the axis.
4. The apparatus of claim 1, wherein the control unit controls a
length of the first time, a length of the second time, a rotation
speed of the mounting stand and a length of a process time such
that, when starting and ending the repetition control, the
workpiece substrate is located at the same position within the
process vessel.
5. The apparatus of claim 4, wherein the control unit sets the
process time to become equal to a time length which is a common
multiple of a length of the time required for the mounting stand to
make one revolution about the axis and a length of the total sum of
the first time and the second time.
6. The apparatus of claim 1, wherein, if the mounting stand makes
one revolution about the axis for x seconds, the process gas supply
unit repeats the first operation and the second operation based on
the first time and the second time which satisfy the following
relational expression: xk.+-.1=m+n where m is the first time
(seconds, a natural number), n is the second time (seconds, a
natural number), and k is an arbitrary natural number.
7. The apparatus of claim 1, wherein the plasma generating unit
includes an antenna configured to irradiate microwaves toward the
second region, and a coaxial waveguide configured to supply the
microwaves to the antenna, wherein line segments defining a
cross-sectional outline of the antenna seen in a direction of the
axis include two line segments which go away from each other as a
distance from the axis increases, and the coaxial waveguide is
configured to supply the microwaves to the antenna from a gravity
center of the antenna.
8. The apparatus of claim 7, wherein the cross-sectional outline of
the antenna seen in the direction of the axis is a shape having
rotational symmetry.
9. The apparatus of claim 7, wherein the cross-sectional outline of
the antenna seen in the direction of the axis is a substantially
equilateral triangular shape.
10. The apparatus of claim 1, wherein the precursor gas contains at
least silane, the first gas contains at least nitrogen, and the
second gas contains at least hydrogen.
11. A substrate processing method implemented in a substrate
processing apparatus which includes a mounting stand provided with
a substrate mounting region in which a workpiece substrate is
mounted, the mounting stand being installed so as to rotate about
an axis such that the substrate mounting region is moved in a
circumferential direction, and a process vessel configured to
define a process chamber which accommodates the mounting stand
therein, the process chamber including a first region and a second
region through which the substrate mounting region moving about the
axis in the circumferential direction upon rotation of the mounting
stand passes in order, the method comprising: an adsorption process
in which an adsorption layer is formed on a surface of the
workpiece substrate by supplying a precursor gas to the first
region; a reaction process in which the surface of the workpiece
substrate is subjected to reaction by supplying a first gas to the
second region and generating plasma of the first gas; and a
modifying process in which the surface of the workpiece substrate
is modified by supplying a second gas differing from the first gas
to the second region and generating plasma of the second gas,
wherein a first operation for performing the reaction process for a
first time and a second operation for performing the modifying
process for a second time are repeated while rotating the mounting
stand.
12. The method of claim 11, wherein the substrate processing
apparatus includes a plurality of plasma generating units disposed
in the second region, the plasma generating units configured to
generate plasma by using the first gas or the second gas in
common.
13. The method of claim 11, wherein the total sum of the first time
and the second time differs in length from the time required for
the mounting stand to make one revolution about the axis.
14. The method of claim 11, wherein a length of the first time, a
length of the second time, a rotation speed of the mounting stand
and a length of a process time are controlled such that, when
starting and ending repetition control, the workpiece substrate is
located at the same position within the process vessel.
15. The method of claim 14, wherein the process time is set to
become equal to a time length which is a common multiple of a
length of the time required for the mounting stand to make one
revolution about the axis and a length of the total sum of the
first time and the second time.
16. The method of claim 11, wherein, if the mounting stand makes
one revolution about the axis for x seconds, the first operation
and the second operation is repeated based on the first time and
the second time which satisfy the following relational expression:
xk.+-.1=m+n where m is the first time (seconds, a natural number),
n is the second time (seconds, a natural number), and k is an
arbitrary natural number.
17. The method of claim 11, wherein the precursor gas contains at
least silane, the first gas contains at least nitrogen, and the
second gas contains at least hydrogen.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of Japanese Patent
Application No. 2014-080532, filed on Apr. 9, 2014, in the Japan
Patent Office, the disclosure of which is incorporated herein in
its entirety by reference.
TECHNICAL FIELD
[0002] Various aspects and embodiments of the present disclosure
relate to a substrate processing apparatus and a substrate
processing method.
BACKGROUND
[0003] As one example of a method for forming a film on a
substrate, a plasma enhanced atomic layer deposition (PE-ALD)
method has been used. In the PE-ALD method, a substrate is exposed
to a precursor gas, whereby the precursor gas which contains a
constituent element of a thin film to be formed is chemisorbed onto
the substrate. Subsequently, the substrate is exposed to a purge
gas, thereby removing the precursor gas excessively chemisorbed
onto the substrate. Then, the substrate is exposed to plasma of a
reaction gas which contains a constituent element of a film to be
formed, consequently forming a desired thin film on the substrate.
In the PE-ALD method, this process is repeated such that a film
obtained by processing atoms or molecules contained in the
precursor gas is formed on the substrate.
[0004] As an apparatus for implementing the PE-ALD method, a
semi-batch type film forming apparatus has been used. In the
semi-batch type film forming apparatus, a region to which the
precursor gas is supplied and a region in which the plasma of the
reaction gas is generated, are independently provided within a
process chamber. The substrate passes through these regions in the
order named. As a result, a desired film is formed on the
substrate.
[0005] In the aforementioned PE-ALD method, film quality is
improved if a modifying process performed using plasma of a
modifying gas such as hydrogen or the like is added after the
adsorption process performed using the precursor gas or after the
reaction process performed using the plasma of the reaction
gas.
[0006] In the semi-batch type film forming apparatus, when
performing the modifying process after the adsorption process or
the reaction process, it is thinkable that, in addition to an
adsorption process region and a reaction process region, a
modifying process region is formed within the process chamber.
However, in this case, it is necessary to independently control the
gases in a region where the plasma of the reaction gas is generated
and in a region where the plasma of the modifying gas is generated.
This poses a drawback in that the cost of the substrate processing
apparatus becomes higher. Furthermore, the gases are mixed in a
region between the region where the plasma of the reaction gas is
generated and the region where the plasma of the modifying gas is
generated. This leads to deterioration of the processing uniformity
and the film quality.
SUMMARY
[0007] According to one embodiment of the present disclosure,
provided is a substrate processing apparatus including: a mounting
stand provided with a substrate mounting region in which a
workpiece substrate is mounted, the mounting stand being installed
so as to rotate about an axis such that the substrate mounting
region is moved in a circumferential direction; a process vessel
configured to define a process chamber which accommodates the
mounting stand therein, the process chamber including a first
region and a second region through which the substrate mounting
region moving about the axis in the circumferential direction upon
rotation of the mounting stand passes in order; a precursor gas
supply unit configured to supply a precursor gas to the first
region; a process gas supply unit configured to supply a first gas
or a second gas differing from the first gas to the second region;
at least one plasma generating unit configured to generate plasma
of the first gas or the second gas in the second region; and a
control unit configured to execute a repetition control of
repeating a first operation for supplying the first gas to the
second region for a first time and a second operation for supplying
the second gas to the second region for a second time.
[0008] According to another embodiment of the present disclosure,
provided is a substrate processing method implemented in a
substrate processing apparatus which includes a mounting stand
provided with a substrate mounting region in which a workpiece
substrate is mounted, the mounting stand being installed so as to
rotate about an axis such that the substrate mounting region is
moved in a circumferential direction, and a process vessel
configured to define a process chamber which accommodates the
mounting stand therein, the process chamber including a first
region and a second region through which the substrate mounting
region moving about the axis in the circumferential direction upon
rotation of the mounting stand passes in order. The method
includes: an adsorption process in which an adsorption layer is
formed on a surface of the workpiece substrate by supplying a
precursor gas to the first region; a reaction process in which the
surface of the workpiece substrate is subjected to reaction by
supplying a first gas to the second region and generating plasma of
the first gas; and a modifying process in which the surface of the
workpiece substrate is modified by supplying a second gas differing
from the first gas to the second region and generating plasma of
the second gas, wherein a first operation for performing the
reaction process for a first time and a second operation for
performing the modifying process for a second time are repeated
while rotating the mounting stand.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The accompanying drawings, which are incorporated in and
constitute a part of the specification, illustrate embodiments of
the present disclosure, and together with the general description
given above and the detailed description of the embodiments given
below, serve to explain the principles of the present
disclosure.
[0010] FIG. 1 is a top view schematically showing a substrate
processing apparatus according to a first embodiment.
[0011] FIG. 2 is a plane view showing a state in which a top
portion of a process vessel is removed from the substrate
processing apparatus shown in FIG. 1.
[0012] FIG. 3 is a sectional view taken along line I-I in the
substrate processing apparatus shown in FIG. 1.
[0013] FIG. 4 is an enlarged sectional view of the portion existing
at the left side of an axis X in FIG. 3.
[0014] FIG. 5 is an enlarged sectional view of the portion existing
at the right side of the axis X in FIG. 3.
[0015] FIG. 6 is a view showing one example of each of five regions
defined by dividing the interior of the process vessel.
[0016] FIG. 7 is a view showing one example of a supply timing of a
NH.sub.3 gas in a case where the supply and cutoff of the NH.sub.3
gas is controlled at 9 seconds per one cycle.
[0017] FIG. 8 is a view showing another example of the supply
timing of the NH.sub.3 gas in a case where the supply and cutoff of
the NH.sub.3 gas is controlled at 9 seconds per one cycle.
[0018] FIG. 9 is a view showing one example of a relationship
between a cutoff time of a NH.sub.3 gas and film quality.
[0019] FIG. 10 is a view showing one example of a relationship
between a cutoff time of a NH.sub.3 gas, a film thickness and
thickness uniformity.
[0020] FIG. 11 is a view showing one example of a relationship
between a deposition rate and film quality.
[0021] FIG. 12 is a top view schematically showing a substrate
processing apparatus according to a second embodiment.
[0022] FIG. 13 is a view showing one example of a supply timing of
a NH.sub.3 gas in case where the supply and cutoff of the NH.sub.3
gas is controlled at 11 seconds per one cycle.
[0023] FIG. 14 is a view showing one example of a relationship
between a cutoff time of a NH.sub.3 gas and film quality.
[0024] FIG. 15 is a view showing one example of a relationship
between a cutoff time of a NH.sub.3 gas, a film thickness and
thickness uniformity.
[0025] FIG. 16 is a view showing one example of a supply timing of
a NH.sub.3 gas in a case where the supply and cutoff of the
NH.sub.3 gas is controlled at 55 seconds per one cycle.
[0026] FIG. 17 is a view showing one example of a relationship
between a cutoff time of a NH.sub.3 gas and film quality.
[0027] FIG. 18 is a view showing one example of a relationship
between a cutoff time of a NH.sub.3 gas, a film thickness and
thickness uniformity.
[0028] FIG. 19 is a view showing one example of a relationship
between a deposition rate and film quality.
[0029] FIG. 20 is a top view schematically showing a substrate
processing apparatus according to a third embodiment.
[0030] FIG. 21 is a view showing one example of a schematic shape
of an antenna.
DETAILED DESCRIPTION
[0031] Reference will now be made in detail to various embodiments,
examples of which are illustrated in the accompanying drawings. In
the following detailed description, numerous specific details are
set forth in order to provide a thorough understanding of the
present disclosure. However, it will be apparent to one of ordinary
skill in the art that the present disclosure may be practiced
without these specific details. In other instances, well-known
methods, procedures, systems, and components have not been
described in detail so as not to unnecessarily obscure aspects of
the various embodiments.
[0032] In one embodiment, a substrate processing apparatus
according to the present disclosure includes: a mounting stand
provided with a substrate mounting region in which a workpiece
substrate is mounted, the mounting stand being installed so as to
rotate about an axis such that the substrate mounting region is
moved in a circumferential direction; a process vessel configured
to define a process chamber which accommodates the mounting stand
therein, the process chamber including a first region and a second
region through which the substrate mounting region moving about the
axis in the circumferential direction upon rotation of the mounting
stand passes in order; a precursor gas supply unit configured to
supply a precursor gas to the first region; a process gas supply
unit configured to supply a first gas or a second gas differing
from the first gas to the second region; at least one plasma
generating unit configured to generate plasma of the first gas or
the second gas in the second region; and a control unit configured
to execute a repetition control of repeating a first operation for
supplying the first gas to the second region for a first time and a
second operation for supplying the second gas to the second region
for a second time.
[0033] In one embodiment of the substrate processing apparatus
according to the present disclosure, the at least one plasma
generating unit may be at least two plasma generating units, and
each of the at least two plasma generating units may include the
process gas supply unit and each process gas supply unit may be
connected to a common process gas supply source.
[0034] In one embodiment of the substrate processing apparatus
according to the present disclosure, the total sum of the first
time and the second time may differ in length from the time
required for the mounting stand to make one revolution about the
axis.
[0035] In one embodiment of the substrate processing apparatus
according to the present disclosure, the control unit may control a
length of the first time, a length of the second time, a rotation
speed of the mounting stand and a length of a process time such
that, when starting and ending the repetition control, the
workpiece substrate is located at the same position within the
process vessel.
[0036] In one embodiment of the substrate processing apparatus
according to the present disclosure, the control unit may set the
process time to become equal to a time length which is a common
multiple of a length of the time required for the mounting stand to
make one revolution about the axis and a length of the total sum of
the first time and the second time.
[0037] In one embodiment of the substrate processing apparatus
according to the present disclosure, if the mounting stand makes
one revolution about the axis for x seconds, the process gas supply
unit repeats the first operation and the second operation based on
the first time and the second time which satisfy the following
relational expression (1):
xk.+-.1=m+n (1)
where m is the first time (seconds, a natural number), n is the
second time (seconds, a natural number), and k is an arbitrary
natural number.
[0038] In one embodiment of the substrate processing apparatus
according to the present disclosure, the plasma generating unit may
include an antenna configured to irradiate microwaves toward the
second region and a coaxial waveguide configured to supply the
microwaves to the antenna, line segments defining a cross-sectional
outline of the antenna seen in a direction of the axis may include
two line segments which go away from each other as the distance
from the axis increases, and the coaxial waveguide may be
configured to supply the microwaves to the antenna from a gravity
center of the antenna.
[0039] In one embodiment of the substrate processing apparatus
according to the present disclosure, the cross-sectional outline of
the antenna seen in the direction of the axis may be a shape having
rotational symmetry.
[0040] In one embodiment of the substrate processing apparatus
according to the present disclosure, the cross-sectional outline of
the antenna seen in the direction of the axis may be a
substantially equilateral triangular shape.
[0041] In one embodiment of the substrate processing apparatus
according to the present disclosure, the precursor gas may contain
at least silane, the first gas may contain at least nitrogen, and
the second gas may contain at least hydrogen.
[0042] A substrate processing method according to the present
disclosure is implemented in a substrate processing apparatus which
includes a mounting stand provided with a substrate mounting region
in which a workpiece substrate is mounted, the mounting stand being
installed so as to rotate about an axis such that the substrate
mounting region is moved in a circumferential direction, and a
process vessel configured to define a process chamber which
accommodates the mounting stand therein, the process chamber
including a first region and a second region through which the
substrate mounting region moving about the axis in the
circumferential direction upon rotation of the mounting stand
passes in order, the method including: an adsorption process in
which an adsorption layer is formed on a surface of the workpiece
substrate by supplying a precursor gas to the first region; a
reaction process in which the surface of the workpiece substrate is
subjected to reaction by supplying a first gas to the second region
and generating plasma of the first gas; and a modifying process in
which the surface of the workpiece substrate is modified by
supplying a second gas differing from the first gas to the second
region and generating plasma of the second gas, wherein a first
operation for performing the reaction process for a first time and
a second operation for performing the modifying process for a
second time are repeated while rotating the mounting stand.
[0043] In one embodiment of the substrate processing method
according to the present disclosure, the substrate processing
apparatus may include a plurality of plasma generating units
disposed in the second region, the plasma generating units
configured to generate plasma by using the first gas or the second
gas in common
[0044] In one embodiment of the substrate processing method
according to the present disclosure, the total sum of the first
time and the second time may differ in length from the time
required for the mounting stand to make one revolution about the
axis.
[0045] In one embodiment of the substrate processing method
according to the present disclosure, a length of the first time, a
length of the second time, a rotation speed of the mounting stand
and a length of a process time may be controlled such that, when
starting and ending repetition control, the workpiece substrate is
located at the same position within the process vessel.
[0046] In one embodiment of the substrate processing method
according to the present disclosure, the process time may be set to
become equal to a time length which is a common multiple of a
length of the time required for the mounting stand to make one
revolution about the axis and a length of the total sum of the
first time and the second time.
[0047] In one embodiment of the substrate processing method
according to the present disclosure, if the mounting stand makes
one revolution about the axis for x seconds, the first operation
and the second operation may be repeated based on the first time
and the second time which satisfy the following relational
expression (1):
xk.+-.1=m+n (1),
where m is the first time (m is a natural number), n is the second
time (n is a natural number), and k is an arbitrary natural
number.
[0048] In one embodiment of the substrate processing method
according to the present disclosure, the precursor gas may contain
at least silane, the first gas may contain at least nitrogen, and
the second gas may contain at least hydrogen.
[0049] Some embodiments of the substrate processing apparatus and
the substrate processing method according to the present disclosure
will now be described in detail with reference to the drawings. The
present disclosure is not limited to these embodiments. The
respective embodiments may be suitably combined unless a conflict
arises in the processing contents.
First Embodiment
[0050] FIG. 1 is a top view schematically showing a substrate
processing apparatus 10 according to a first embodiment. FIG. 2 is
a plane view showing a state in which a top portion of a process
vessel 12 is removed from the substrate processing apparatus 10
shown in FIG. 1. FIG. 3 is a sectional view taken along line I-I in
the substrate processing apparatus 10 shown in FIG. 1. FIG. 4 is an
enlarged sectional view of the portion existing at the left side of
an axis X in FIG. 3. FIG. 5 is an enlarged sectional view of the
portion existing at the right side of the axis X in FIG. 3. The
substrate processing apparatus 10 shown in FIGS. 1 to 5 essentially
includes a process vessel 12, a mounting stand 14, a precursor gas
supply unit 16, an exhaust unit 18, a purge gas supply unit 20, and
a plurality of plasma generating units 22.
[0051] The process vessel 12 is a substantially cylindrical vessel
having a center axis coinciding with a vertical axes X. The process
vessel 12 includes a process chamber C defined therein. The process
chamber C includes a unit U provided with an injection part 16a.
The process vessel 12 is made of metal such as Al (aluminum) or the
like. The inner surface of the process vessel 12 is subjected to an
anti-plasma treatment such as, e.g., an alumite treatment or a
thermal spray treatment of Y.sub.2O.sub.3 (yttrium oxide).
[0052] The substrate processing apparatus 10 includes the plasma
generating units 22 disposed above the process vessel 12. The
plasma generating units 22 are respectively installed in three
consecutive regions among five substantially-equal fan-shaped
regions defined by dividing a substantially circular plane existing
above the process vessel 12 about the axis X. Each of the plasma
generating units 22 includes an antenna 22a configured to output
microwaves. The antenna 22a includes a dielectric plate 40 disposed
therein. The antenna 22a further includes a waveguide 42 installed
on the dielectric plate 40. The number of divisions of the
substantially circular plane existing above the process vessel 12,
the number of the plasma generating units 22 installed and the
position of the unit U are not limited to the ones illustrated in
FIGS. 1 and 2 but may be appropriately changed.
[0053] As shown in FIG. 2, the substrate processing apparatus 10
includes the mounting stand 14 which has a plurality of substrate
mounting regions 14a on the upper surface thereof. The mounting
stand 14 is a substantially disc-shaped plate having a center axis
coinciding with the axis X. The substrate mounting regions 14a,
which are concave portions for mounting substrates W, are formed on
the upper surface of the mounting stand 14. The concave portions
are concentrically formed on a planar surface. In the present
embodiment, for example, five concave portions are concentrically
formed on the upper surface of the mounting stand 14 about the axis
X. The substrates W are supported so as not to be shifted when they
are disposed within the concave portions and are rotated. The
concave portions have a substantially circular shape which is
substantially identical with the shape of the substrates W. The
diameter W1 of the concave portions is substantially equal to the
diameter of the substrates W. That is to say, the diameter W1 of
the concave portions may be set such that the substrates W are
fitted to the concave portions and such that the substrates W are
fixed and are not moved out of the fitted positions by a
centrifugal force even when the mounting stand 14 is rotated.
[0054] The substrate processing apparatus 10 includes a gate valve
G installed in the outer edge of the process vessel 12 such that
the substrates W can be carried into and out of the process chamber
C through the gate valve G by virtue of a transfer device such as a
robot arm or the like. Furthermore, the substrate processing
apparatus 10 includes an exhaust port 22h formed below the outer
edge of the mounting stand 14. The substrate processing apparatus
10 keeps the internal pressure of the process chamber C at a
desired pressure by evacuating the interior of the process chamber
C through the exhaust port 22h.
[0055] As shown in FIG. 3, the process vessel 12 includes a lower
member 12a and an upper member 12b. The lower member 12a has an
upwardly-opened substantially-cylindrical shape and forms a recess
portion including a sidewall and a bottom wall for defining the
process chamber C. The upper member 12b is a lid which has a
substantially cylindrical shape and which forms the process chamber
C by covering and closing an upper opening of the recess portion of
the lower member 12a. An elastic sealing member, e.g., an O-ring,
for sealing the process chamber C may be installed in an outer
periphery portion between the lower member 12a and the upper member
12b.
[0056] The mounting stand 14 is rotationally driven about the axis
X by a drive mechanism 24. The drive mechanism 24 includes a
driving device 24a such as a motor or the like and a rotating shaft
24b. The drive mechanism 24 is installed in the lower member 12a of
the process vessel 12.
[0057] The rotating shaft 24b extends into the process chamber C
along a center axis coinciding with the axis X. The rotating shaft
24b is rotated, e.g., clockwise, about the axis X by a driving
force transmitted from the driving device 24a. The central portion
of the mounting stand 14 is supported by the rotating shaft 24b.
Thus, upon rotating the rotating shaft 24b, the mounting stand 14
is rotated about the axis X. An elastic sealing member, such as an
O-ring or the like, for sealing the process chamber C may be
installed between the lower member 12a of the process vessel 12 and
the drive mechanism 24.
[0058] The substrate processing apparatus 10 includes a heater 26
disposed below the mounting stand 14 within the process chamber C
and configured to heat the substrates W mounted in the substrate
mounting regions 14a. Specifically, the heater 26 heats the
mounting stand 14, thereby heating the substrates W. The process
chamber C includes a first region R1 arranged in a planar shape on
a circumference centered at the axis X (see FIG. 2) and a second
region R2. Upon rotating the mounting stand 14, the substrates W
mounted in the substrate mounting regions 14a pass through the
first region R1 and the second region R2.
[0059] For example, as shown in FIG. 4, the substrate processing
apparatus 10 includes the precursor gas supply unit 16 disposed
above the first region R1 so as to face the upper surface of the
mounting stand 14. The precursor gas supply unit 16 includes an
injection part 16a. That is to say, the region facing the injection
part 16a among the regions included in the process chamber C is the
first region R1.
[0060] The injection part 16a includes a plurality of injection
holes 16h. The precursor gas supply unit 16 supplies a precursor
gas to the first region R1 through the plurality of injection holes
16h. As the precursor gas is supplied to the first region R1, the
atoms or molecules of the precursor gas is chemisorbed onto the
surfaces of the substrates W passing through the first region R1.
The precursor gas is, e.g., a gas which contains at least silane.
The precursor gas is, e.g., DCS (dichlorosilane), monochlorosilane
or trichlorosilane. For example, if the precursor gas is DCS, Si
(silicon) is chemisorbed onto the surfaces of the substrates W as
the substrates W pass through the first region R1.
[0061] An exhaust hole 18a of the exhaust unit 18 is formed above
the first region R1 so as to face the upper surface of the mounting
stand 14. The exhaust hole 18a is formed around the injection part
16a. The exhaust unit 18 exhausts the gas existing within the
process chamber C through the exhaust hole 18a using the operation
of an exhaust device 34 such as a vacuum pump or the like.
[0062] An injection hole 20a of the purge gas supply unit 20 is
formed above the first region R1 so as to face the upper surface of
the mounting stand 14. The injection hole 20a is formed around the
exhaust hole 18a. The purge gas supply unit 20 supplies a purge gas
to the first region R1 through the injection hole 20a. The purge
gas supplied by the purge gas supply unit 20 is an inert gas such
as, e.g., Ar (argon) or the like. As the purge gas is injected
toward the surfaces of the substrates W, the atoms or molecules of
the precursor gas (the residual gas components) excessively
adsorbed onto the substrates W are removed from the substrates W.
Thus, layers onto which a specified amount of atoms or molecules of
the precursor gas is adsorbed are formed on the surfaces of the
substrates W.
[0063] The substrate processing apparatus 10 injects the purge gas
from the injection hole 20a and exhausts the purge gas from the
exhaust hole 18a along the surface of the mounting stand 14. Thus,
the exhaust unit 18 restrains the precursor gas supplied to the
first region R1 from being leaked out of the first region R1. Since
the substrate processing apparatus 10 injects the purge gas from
the injection hole 20a and exhausts the purge gas from the exhaust
hole 18a along the surface of the mounting stand 14, it is possible
to restrain the reaction gas or radicals of the reaction gas
supplied to the second region R2 from infiltrating into the first
region R1. That is to say, the substrate processing apparatus 10 is
configured to isolate the first region R1 and the second region R2
using the injection of the purge gas from the purge gas supply unit
20 and the exhaust operation of the exhaust unit 18.
[0064] The substrate processing apparatus 10 is provided with a
unit U which includes the injection part 16a, the exhaust hole 18a
and the injection hole 20a. That is to say, the injection part 16a,
the exhaust hole 18a and the injection hole 20a are formed as
portions which constitute the unit U. For example, as shown in FIG.
4, the unit U is configured by sequentially stacking a first member
Ml, a second member M2, a third member M3 and a fourth member M4.
The unit U is installed in the process vessel 12 so as to make
contact with the lower surface of the upper member 12b of the
process vessel 12.
[0065] For example, as shown in FIG. 4, a gas supply path 16p
extending through the second member M2, the third member M3 and the
fourth member M4 is formed in the unit U. The gas supply path 16p
is connected at its upper end to a gas supply path 12p installed in
the upper member 12b of the process vessel 12. A gas supply source
16g for supplying a precursor gas is connected to the gas supply
path 12p through a valve 16v and a flow rate controller 16c such as
a mass flow controller or the like. Furthermore, the lower end of
the gas supply path 16p is connected to a space 16d defined between
the first member M1 and the second member M2. The injection holes
16h of the injection part 16a installed in the first member M1 are
connected to the space 16d.
[0066] A gas supply path 20r extending through the fourth member M4
is formed in the unit U. The gas supply path 20r is connected at
its upper end to a gas supply path 12r installed in the upper
member 12b of the process vessel 12. A purge gas supply source 20g
is connected to the gas supply path 12r through a valve 20v and a
flow rate controller 20c such as a mass flow controller or the
like.
[0067] In the unit U, the lower end of the gas supply path 20r is
connected to a space 20d defined between the lower surface of the
fourth member M4 and the upper surface of the third member M3.
Furthermore, the fourth member M4 is configured to define a recess
portion which accommodates the first member M1, the second member
M2 and the third member M3. A gap 20p is formed between a side
surface of the fourth member M4 defining the recess portion and a
side surface of the third member M3. The gap 20p is connected to
the space 20d.
[0068] An exhaust path 18q extending through the third member M3
and the fourth member M4 is formed in the unit U. The exhaust path
18q is connected at its upper end to an exhaust path 12q formed in
the upper member 12b of the process vessel 12. The exhaust path 12q
is connected to the exhaust device 34 such as a vacuum pump or the
like. Furthermore, the exhaust path 18q is connected at it lower
end to a space 18d defined between the lower surface of the third
member M3 and the upper surface of the second member M2.
[0069] The third member M3 includes a recess portion which
accommodates the first member M1 and the second member M2. A gap
18g is formed between an inner surface of the third member M3
defining the recess portion of the third member M3 and side end
surfaces of the first member M1 and second member M2. The space 18d
is connected to the gap 18g. The lower end of the gap 18g serves as
the exhaust hole 18a. The substrate processing apparatus 10 injects
a purge gas from the injection hole 20a and exhausts the purge gas
from the exhaust hole 18a along the surface of the mounting stand
14, thereby restraining the precursor gas supplied to the first
region R1 from being leaked out of the first region R1.
[0070] For example, as shown in FIG. 5, the substrate processing
apparatus 10 includes the plasma generating units 22 disposed above
the second region R2, which is an opening of the upper member 12b,
so as to face the upper surface of the mounting stand 14. For
example, as shown in FIG. 2, the opening of the plasma generating
unit 22 has a substantially fan-shape. In the present embodiment,
three openings are formed in the upper member 12b. The substrate
processing apparatus 10 includes, e.g., three plasma generating
units 22.
[0071] In the reaction process, the plasma generating units 22
supplies a reaction gas and microwaves to the second region R2,
thereby forming plasma of the reaction gas in the second region R2.
If a nitrogen-containing gas is used as the reaction gas, the
active species generated by the plasma react with the layers of
atoms or molecules chemisorbed onto the substrates W, thereby
nitriding the layers of atoms or molecules chemisorbed onto the
substrates W. As the reaction gas, it may be possible to use a
nitrogen-containing gas such as a N.sub.2 (nitrogen) gas or a
NH.sub.3 (ammonia) gas, a H.sub.2 (hydrogen) gas, or a mixture gas
obtained by appropriately mixing these gases. In the present
embodiment, a mixture gas of the NH.sub.3 gas and the H.sub.2 gas
is used as the reaction gas. In the reaction process, the flow rate
of the NH.sub.3 gas is, e.g., 1,500 sccm and the flow rate of the
H.sub.2 gas is, e.g., 150 sccm.
[0072] In the modifying process, the plasma generating units 22
supply a modifying gas and microwaves to the second region R2,
thereby generating plasma of the modifying gas in the second region
R2. The nitride films formed on the surfaces of the substrates W
can be modified by the active species generated by the plasma of
the modifying gas. As the modifying gas, it may be possible to use
one of a N.sub.2 gas, a NH.sub.3 gas, an Ar (argon) gas and a
H.sub.2 gas, or a mixture gas obtained by appropriately mixing
these gases. In the present embodiment, the H.sub.2 gas is used as
the modifying gas. In the modifying process, the flow rate of the
H.sub.2 gas is, e.g., 150 sccm.
[0073] For example, as shown in FIG. 5, in the plasma generating
units 22, a dielectric plate 40 is hermetically disposed so as to
close an aperture AP. A waveguide 42 is disposed on the dielectric
plate 40. An internal space 42i, which is a waveguide path for
propagating microwaves, is formed within the waveguide 42. An
antenna 22a for supplying microwaves to the second region R2 is
installed on the upper surface between the waveguide 42 and the
dielectric plate 40. The dielectric plate 40 is a substantially
plate-shaped member made of a dielectric material such as SiO.sub.2
(quartz) or the like. The dielectric plate 40 is installed so as to
face the second region R2. The dielectric plate 40 is supported on
the upper member 12b of the process vessel 12.
[0074] For example, as shown in FIG. 5, an aperture AP is formed in
the upper member 12b of the process vessel 12 such that the
dielectric plate 40 is exposed to the second region R2. The plane
size of the upper portion of the aperture AP is larger than the
plane size of the lower portion of the aperture AP. The term "plane
size" refers to the cross-sectional area on a plane orthogonal to
the axis X. A substantially L-like step surface 12s is formed in
the portion of the upper member 12b which defines the aperture AP.
The edge portion of the dielectric plate 40 serves as a supported
portion 40s which makes air-tight contact with the step surface 12s
through an 0-ring or the like. As the supported portion 40s makes
contact with the step surface 12s, the dielectric plate 40 is
supported on the upper member 12b.
[0075] In the dielectric plate 40 supported by the upper member
12b, the portion facing the mounting stand 14 through the second
region R2, namely the portion facing the second region
[0076] R2, serves as a dielectric window 40w. The waveguide 42 is
installed on the dielectric plate 40 such that the internal space
42i radially extends with respect to the axis X.
[0077] A slot plate 42a is a plate-shaped member made of metal. The
slot plate 42a forms a lower surface of the internal space 42i. The
slot plate 42a makes contact with the upper surface of the
dielectric plate 40 and covers the upper surface of the dielectric
plate 40. The slot plate 42a includes a plurality of slot holes 42s
formed in the portion which defines the internal space 42i.
[0078] A metal-made top member 42b is installed above the slot
plate 42a so as to cover the slot plate 42a. The top member 42b
forms an upper surface of the internal space 42i of the waveguide
42. The top member 42b is screw-fixed to the upper member 12b such
that the slot plate 42a and the dielectric plate 40 are sandwiched
between the top member 42b and the upper member 12b of the process
vessel 12.
[0079] An end member 42c is a metal-made member. The end member 42c
is installed at one longitudinal end of the waveguide 42. That is
to say, the end member 42c is installed at one ends of the slot
plate 42a and the top member 42b so as to close one end of the
internal space 42i. A microwave generator 48 is connected to the
other end of the waveguide 42.
[0080] The microwave generator 48 generates microwaves of, e.g.,
about 2.45 GHz, and supplies the microwaves to the waveguide 42.
The microwaves generated by the microwave generator 48 are
propagated within the internal space 42i of the waveguide 42 and
are propagated to the dielectric plate 40 through the slot holes
42s of the slot plate 42a. The microwaves propagated to the
dielectric plate 40 are transmitted through the dielectric plate 40
and supplied to the second region R2.
[0081] The modifying gas is one of a N.sub.2 gas, a NH.sub.3 gas,
an Ar gas and a H.sub.2 gas, or a mixture gas obtained by
appropriately mixing these gases. A process gas supply unit 22b is
installed at the inner circumference side of the opening of the
upper member 12b. The process gas supply unit 22b includes a gas
supply part 50a and an injection part 50b.
[0082] The gas supply part 50a is formed within the upper member
12b of the process vessel 12 so as to extend, e.g., around the
aperture AP. The injection part 50b for injecting a reaction gas or
a modifying gas toward the lower side of the dielectric window 40w
is formed so as to communicate with the gas supply part 50a. A gas
supply source 50g is connected to the gas supply part 50a through a
valve 50v and a flow rate control unit 50c such as a mass flow
controller or the like. Furthermore, a gas supply source 51 g is
connected to the gas supply part 50a through a valve 51v and a flow
rate control unit 51c such as a mass flow controller or the like.
In the present embodiment, the gas supply source 50g supplies,
e.g., a NH.sub.3 gas and the gas supply source 51g supplies, e.g.,
a H.sub.2 gas.
[0083] In a case where a reaction gas is supplied to the second
region R2, the valves 50v and 51v are controlled to come into an
open state. The flow rate control unit 50c supplies a NH.sub.3 gas
from the gas supply source 50g to the second region R2 at a
specified flow rate. The flow rate control unit 51c supplies a
H.sub.2 gas from the gas supply source 51g to the second region R2
at a specified flow rate. Thus, a reaction gas, which is a mixture
gas of the NH.sub.3 gas supplied at a specified flow rate and the
H.sub.2 gas supplied at a specified flow rate, is supplied to the
second region R2.
[0084] In a case where a modifying gas is supplied to the second
region R2, the valve 50v is controlled to come into a closed state
and the valve 51v is controlled to come into an open state. The
flow rate control unit 51c supplies a H.sub.2 gas from the gas
supply source 51g to the second region R2 at a specified flow rate.
Thus, a modifying gas, which is the H.sub.2 gas supplied at a
specified flow rate, is supplied to the second region R2.
[0085] In a state in which the reaction gas or the modifying gas is
supplied to the second region R2 by the process gas supply unit
22b, each of the plasma generating units 22 causes the antenna 22a
to supply microwaves to the second region R2, thereby generating
plasma of the reaction gas or the modifying gas in the second
region R2.
[0086] If there is a plurality of plasma generating units 22, it is
necessary to supply the gases to the respective plasma generating
units 22. In this case, a process gas is divisionally supplied to
the plasma generating units 22. Therefore, as compared with a case
where gas supply sources and flow rate control units are installed
in the respective plasma generating units 22, it is possible to
reduce the cost of the substrate processing apparatus 10. Since the
gas supplied from the respective plasma generating units 22 is used
in common, there is no possibility that the processing performance
is deteriorated due to the mixture of different process gases.
[0087] For example, as shown in FIG. 2, the angular extent over
which the second region R2 extends in the circumferential direction
of the axis X is set larger than the angular extent over which the
first region R1 extends in the circumferential direction. Thus, the
layers of atoms or molecules adsorbed onto the substrates W are
exposed for a long time to the plasma of the reaction gas or the
modifying gas generated in the second region R2, whereby the layers
are efficiently processed. For example, the layers of Si adsorbed
onto the substrates W are efficiently nitrided by free radicals
(radicals) of N.sub.2.
[0088] For example, as shown in FIG. 2, the exhaust port 22h is
formed in the lower member 12a of the process vessel 12 at a
position below the outer edge of the mounting stand 14. An exhaust
device 52 is connected to the exhaust port 22h. In the substrate
processing apparatus 10, the pressure in the second region R2 is
kept at a target pressure by the evacuation from the exhaust port
22h through the operation of the exhaust device 52.
[0089] For example, as shown in FIG. 3, the substrate processing
apparatus 10 includes a control unit 60 for controlling the
respective constituent elements of the substrate processing
apparatus 10. The control unit 60 may be a computer which includes
a control device such as a CPU (Central Processing Unit) or the
like, a memory device such as a memory or the like, an input/output
device, and so forth. In the control unit 60, the CPU is operated
pursuant to a control program stored in a memory, thereby
controlling the respective constituent elements of the substrate
processing apparatus 10.
[0090] The control unit 60 transmits a control signal for
controlling the rotation speed of the mounting stand 14, to the
driving device 24a. Furthermore, the control unit 60 sends a
control signal for controlling the temperature of the substrates W,
to a power source connected to the heater 26. Moreover, the control
unit 60 sends a control signal for controlling the flow rate of the
precursor gas, to the valve 16v and the flow rate controller 16c.
In addition, the control unit 60 transmits a control signal for
controlling the exhaust amount of the exhaust device 34 connected
to the exhaust hole 18a, to the exhaust device 34.
[0091] Furthermore, the control unit 60 transmits a control signal
for controlling the flow rate of the purge gas, to the valve 20v
and the flow rate controller 20c. Moreover, the control unit 60
transmits a control signal for controlling the power of microwaves,
to the microwave generator 48. Furthermore, the control unit 60
transmits a control signal for controlling the flow rate of, e.g.,
a NH.sub.3 gas included in the reaction gas, to the valve 50v and
the flow rate control unit 50c, and transmits a control signal for
controlling the flow rate of, e.g., a H.sub.2 gas included in the
reaction gas, to the valve 51v and the flow rate control unit 51c.
Moreover, the control unit 60 transmits a control signal for
controlling the flow rate of the modifying gas, to the valve 51v
and the flow rate control unit 51c. In addition, the control unit
60 transmits a control signal for controlling the exhaust amount,
to the exhaust device 34 and the exhaust device 52.
[0092] FIG. 6 is a view showing one example of each of five regions
defined by dividing the interior of the process vessel 12.
Referring to FIG. 6, the region in which the unit U is disposed
will be defined as a region Ad. The region which is positioned
adjacent to the region Ad at the clockwise side in FIG. 6 and in
which the gate valve G is disposed will be defined as a region G.
The region which is positioned adjacent to the region G at the
clockwise side in FIG. 6 and in which the plasma generating unit 22
is disposed will be defined as a region A1. The region which is
positioned adjacent to the region A1 at the clockwise side in FIG.
6 and in which the plasma generating unit 22 is disposed will be
defined as a region A2. The region which is positioned adjacent to
the region A2 at the clockwise side in FIG. 6 and in which the
plasma generating unit 22 is disposed will be defined as a region
A3.
[0093] In the present embodiment, the control unit 60 transmits a
control signal for achieving a rotation speed at which the mounting
stand 14 makes one revolution for a specified number of seconds, to
the driving device 24a. The driving device 24a rotates the mounting
stand 14 at a rotation speed at which the mounting stand 14 makes
one revolution for a specified number of seconds. In the present
embodiment, the control unit 60 transmits a control signal for
rotating the mounting stand 14 clockwise when seen from above, to
the driving device 24a.
[0094] In the example shown in FIG. 6, the control unit 60
transmits a control signal for achieving a rotation speed at which
the mounting stand 14 makes one revolution for, e.g., 5 seconds, to
the driving device 24a. The driving device 24a rotates the mounting
stand 14 at a rotation speed at which the mounting stand 14 makes
one revolution for 5 seconds, namely at 12 rpm.
[0095] In the region Ad, the precursor gas is supplied from the
injection part 16a of the unit U. Exhaust is performed from the
exhaust hole 18a formed around the injection part 16a. The purge
gas is supplied from the injection hole 20a formed around the
exhaust hole 18a. Upon rotating the mounting stand 14, the
substrates W pass below the injection part 16a of the unit U
disposed within the region Ad, thereby performing an adsorption
process in which the precursor gas is chemisorbed onto the
substrates W. Furthermore, upon rotating the mounting stand 14, the
substrates W pass below the exhaust hole 18a of the unit U disposed
within the region Ad, thereby performing a purge process in which
the atoms or molecules of the precursor gas excessively adsorbed
onto the substrates W are removed from the substrates W.
[0096] In the regions A1 to A3, the reaction gas or the modifying
gas is supplied from the process gas supply unit 22b while the
microwaves are supplied by the antenna 22a. Thus, plasma of the
reaction gas or the modifying gas is generated in the regions A1 to
A3. In a case where the reaction gas is supplied from the process
gas supply unit 22b to the regions A1 to A3, upon rotating the
mounting stand 14, the substrates W pass through the regions A1 to
A3 in which the plasma of the reaction gas is generated, thereby
performing a reaction process in which the layers of atoms or
molecules chemisorbed onto the substrates W are nitrided. In a case
where the supply of the reaction gas from the process gas supply
unit 22b is stopped and the modifying gas is supplied from the
process gas supply unit 22b to the regions A1 to A3, upon rotating
the mounting stand 14, the substrates W pass through the regions A1
to A3 in which the plasma of the modifying gas is generated,
thereby performing a modifying process in which the nitride films
of the substrates W are modified.
[0097] In the region G, there is installed a mechanism for
detecting the positions of the substrates W. For that reason, a
shower head (a unit U) or a plasma generating unit 22 cannot be
installed. In the rotation direction of the mounting stand 14, the
region G is disposed adjacent to the back side of the region Ad in
which a shower head is installed. Thus, if the purge performed in
the region Ad is insufficient, the region G serves as a buffer
region between the region Ad in which the purge process is
performed with respect to the substrates W and the region A1 in
which the reaction process or the modifying process is performed
with respect to the substrates W. Accordingly, while the substrates
W are moved to the region A1 after the purge process, it is
possible to reduce impurities such as C1 and the like remaining
near the substrates W. This makes it possible to improve the
quality of films formed on the substrates W.
[0098] Upon rotating the mounting stand 14, the substrates W are
subjected to an adsorption process and a purge process in the
region Ad. After the substrates W pass through the region G, if the
plasma of the reaction gas is generated in the regions A1 to A3,
the substrates W are subjected to a reaction process while the
substrates W pass through the regions A1 to A3. On the other hand,
if the plasma of the modifying gas is generated in the regions A1
to A3, the substrates W are subjected to a modifying process while
the substrates W pass through the regions A1 to A3 along with the
rotation of the mounting stand 14.
[0099] In the present embodiment, with respect to the process gas
supply unit 22b, the control unit 60 executes a repetition control
of repeating a first operation for supplying the reaction gas to
the regions A1 to A3 for a first time and a second operation for
supplying the modifying gas to the regions A1 to A3 for a second
time. While the reaction gas is supplied to the regions A1 to A3,
the plasma of the reaction gas is generated in the regions A1 to
A3. While the modifying gas is supplied to the regions A1 to A3,
the plasma of the modifying gas is generated in the regions A1 to
A3.
[0100] In this regard, the control unit 60 transmits a control
signal to the valves 50v and 51v and the flow rate control units
50c and 51c so as to repeat the first operation and the second
operation based on the values of m and n which satisfy, e.g., the
following relational expression (1):
xk.+-.1=m+n (1),
where x is the time required for the mounting stand 14 to make one
revolution, m is the time (seconds, a natural number) during which
the reaction gas is supplied to the regions A1 to A3, n is the time
(seconds, a natural number) during which the modifying gas is
supplied to the regions A1 to A3, and k is an arbitrary natural
number.
[0101] Thus, the process gas supply unit 22b repeats an operation
for supplying the reaction gas to the regions A1 to A3 for m
seconds and an operation for stopping the supply of the reaction
gas and supplying the modifying gas to the regions A1 to A3 for n
seconds. The relational expression (1) noted above may be either
xk+1=m+n or xk-1=m+n.
[0102] In the relational expression (1) noted above, the m+n
denotes the time required in performing one cycle of supply and
cutoff of the reaction gas. Inasmuch as the time required for the
mounting stand 14 to make one revolution is x seconds, the xk
denotes the time required for the mounting stand 14 to make k
revolutions. Thus, the relational expression (1) noted above means
that, if the mounting stand 14 makes k revolutions, a deviation of
1 second exists between the time required for the mounting stand 14
to make k revolutions and the time required in performing one cycle
of supply and cutoff of the reaction gas.
[0103] It is now assumed that the division number of the process
vessel 12 is y. In the present embodiment, the number of seconds x
of the time required for the mounting stand 14 to make one
revolution is equal to the division number y of the process vessel
12. That is to say, x=y. Thus, the time required for the substrates
W to pass through each of the divided compartments within the
process vessel 12 is 1 second. Accordingly, in the relational
expression (1) noted above, if the mounting stand 14 makes k
revolutions, a deviation of 1 second, namely a deviation
corresponding to the time required for the substrates W to pass
through one compartment within the process vessel 12, exists
between the time required for the mounting stand 14 to make k
revolutions and the time required in performing one cycle of supply
and cutoff of the reaction gas.
[0104] If the cycle of supply and cutoff of the reaction gas is
repeated x times, the cumulative value of the deviation between the
time required for the mounting stand 14 to make k revolutions and
the time required in performing one cycle of supply and cutoff of
the reaction gas becomes equal to the time required for the
substrates W to pass through y compartments within the process
vessel 12, namely the time corresponding to one lap. In an
alternative example, the number of seconds of the time required for
the mounting stand 14 to make one revolution may not be equal to
the division number y of the process vessel 12.
[0105] In the present embodiment, when supplying a reaction gas to
the regions A1 to A3, the control unit 60 controls the flow rate
control unit 50c and the flow rate control unit 51c such that a
mixture gas of a NH.sub.3 gas having a flow rate of, e.g., 1,500
sccm and a H.sub.2 gas having a flow rate of, e.g., 150 sccm is
supplied as the reaction gas. When supplying a modifying gas to the
regions A1 to A3, the control unit 60 controls the flow rate
control unit 51c such that a H.sub.2 gas having a flow rate of,
e.g., 150 sccm is supplied as the modifying gas.
[0106] If the supply of the NH.sub.3 gas included in the reaction
gas is stopped or the supply of the NH.sub.3 gas thus stopped is
resumed while the substrates W pass through the regions A1 to A3, a
period during which the flow rate of the NH.sub.3 gas has, e.g., an
intermediate value between 0 sccm and 1,500 sccm is generated. In
this period, there may be a case where desired nitride films are
not formed on the substrates W exposed to the plasma of the
reaction gas. If the time required for the mounting stand 14 to
make one revolution is equal to the time required in performing one
cycle of supply and cutoff of the reaction gas, the substrates W
passing through the regions A1 to A3 in the period during which the
flow rate of the NH.sub.3 gas has, e.g., an intermediate value
between 0 sccm and 1,500 sccm, are designated as specific
substrates W among the substrates W mounted on the mounting stand
14. Thus, the film quality of the specific substrates W among the
substrates W mounted on the mounting stand 14 becomes poor.
[0107] In contrast, in the substrate processing apparatus 10 of the
present embodiment, the time required for the mounting stand 14 to
make k revolutions is deviated from the time required in performing
one cycle of supply and cutoff of the reaction gas. Thus, the
influence of supply and cutoff of the NH.sub.3 gas can be
distributed to the plurality of substrates W mounted on the
mounting stand 14. This makes it possible to avoid a risk of
production of substrates W having extremely poor quality.
Accordingly, it is possible to produce substrates W with a small
variation in quality.
[0108] In order to obtain this effect, the time which is a common
multiple of the time x required for the mounting stand 14 to make
one revolution and the time (m+n) required in performing one cycle
of supply and cutoff of the reaction gas may be set as a process
time. By arbitrarily setting the x and the (m+n), it is possible to
calculate a process time complying with conditions and to perform
processing for the process time. Moreover, the (m+n) may be
calculated by arbitrarily setting the x and the process time. The x
may be calculated by arbitrarily setting the (m+n) and the process
time.
[0109] For example, if two is selected as the value of k in the
relational expression (1) noted above, each time when the mounting
stand 14 makes two revolutions, the time required for the mounting
stand 14 to make two revolutions and the time required in
performing one cycle of supply and cutoff of the NH.sub.3 gas are
deviated from each other by the time required for the substrates W
to pass through one compartment within the process vessel 12. In
this case, the division number y of the interior of the process
vessel 12 is 5 and the time x required for the mounting stand 14 to
make one revolution is 5 seconds in the present embodiment.
Therefore, if the mounting stand 14 makes ten revolutions, the
cumulative value of the deviation between the time for the mounting
stand 14 to make two revolutions and the time required in
performing one cycle of supply and cutoff of the NH.sub.3 gas
becomes equal to the time required for the substrates W to pass
through five compartments within the process vessel 12, namely 5
seconds which is the time corresponding to one lap. Thus, if the
mounting stand 14 makes ten revolutions, the influence of the
switching of the NH.sub.3 gas can be distributed to the respective
substrates W mounted on the mounting stand 14. As a result, by
setting the revolution number of the mounting stand 14 to become a
multiple of 10, it is possible to reduce the variation in the film
quality of the respective substrates W mounted on the mounting
stand 14.
[0110] In the relational expression (1) noted above, the values of
m and n may be arbitrarily selected within a range in which the
total sum of m and n becomes equal to xk.+-.1. If the division
number y of the process vessel 12 is 5, if the number of seconds x
of the time required for the mounting stand 14 to make one
revolution is 5, and if the value of k is 2, xk-1=9. Therefore, it
is possible to select, e.g., 7 as the m and to select, e.g., 2 as
the n within a range in which the time m+n required in performing
one cycle of supply and stop of the NH.sub.3 gas becomes equal to
9. If 7 seconds is selected as the supply time m of the NH.sub.3
gas and if 2 seconds is selected as the cutoff time n of the
NH.sub.3 gas, the supply timing of the NH.sub.3 gas becomes, for
example, as shown in FIG. 7.
[0111] FIG. 7 is a view showing one example of a supply timing of a
NH.sub.3 gas in a case where the supply and cutoff of the NH.sub.3
gas is controlled at 9 seconds per one cycle. Symbols "A1", "A2",
"A3", "Ad" and "G" shown in FIG. 7 designate the region A1, the
region A2, the region A3, the region Ad and the region G,
respectively, which are defined within the process vessel 12.
[0112] As shown in FIG. 7, the H.sub.2 gas used as one example of
the modifying gas in the present embodiment is supplied to the
regions A1 to A3 regardless of the supply or cutoff of the NH.sub.3
gas. On the other hand, in the case of the NH.sub.3 gas, the supply
of the NH.sub.3 gas to the regions A1 to A3 for 7 seconds and the
cutoff of the NH.sub.3 gas for 2 seconds are repeated. Since the
mounting stand 14 makes one revolution for 5 seconds, the time
required for the mounting stand 14 to make two revolutions is 10
seconds. The time required in performing one cycle of supply and
cutoff of the NH.sub.3 gas is 9 (=7+2) seconds. Thus, the time
required for the mounting stand 14 to make two revolutions and the
time required in performing one cycle of supply and cutoff of the
NH.sub.3 gas are deviated from each other by 1 second every two
revolution of the mounting stand 14, namely by the time required
for the substrates W to pass through one compartment within the
process vessel 12. If the mounting stand 14 makes ten revolutions,
the cumulative value of the deviation between 10 seconds which is
the time required for the mounting stand 14 to make two revolutions
and 9 seconds which is the time required in performing one cycle of
supply and cutoff of the NH.sub.3 gas becomes equal to the time
required for the substrates W to pass through five compartments
defined within the process vessel 12, namely 5 seconds which is the
time corresponding to one lap.
[0113] Within a range in which the time m+n required in performing
one cycle of supply and cutoff of the NH.sub.3 gas becomes 9
seconds, if the supply time m of the NH.sub.3 gas is selected to
become, e.g., 5 seconds and the cutoff time n of the NH.sub.3 gas
is selected to become, e.g., 4 seconds, the supply timing of the
NH.sub.3 gas becomes, for example, as shown in FIG. 8. FIG. 8 is a
view showing another example of the supply timing of the NH.sub.3
gas in a case where the supply and cutoff of the NH.sub.3 gas is
controlled at 9 seconds per one cycle.
[0114] As shown in FIG. 8, in the case of the NH.sub.3 gas, the
supply of the NH.sub.3 gas to the regions A1 to A3 for 5 seconds
and the cutoff of the NH.sub.3 gas for 4 seconds are repeated. In
the example shown in FIG. 8, the time required for the mounting
stand 14 to make two revolutions and the time required in
performing one cycle of supply and cutoff of the NH.sub.3 gas are
deviated from each other by 1 second every two revolutions of the
mounting stand 14, namely by the time required for the substrates W
to pass through one compartment within the process vessel 12. If
the mounting stand 14 makes ten revolutions, the cumulative value
of the deviation between 10 seconds which is the time required for
the mounting stand 14 to make two revolutions and 9 seconds which
is the time required in performing one cycle of supply and cutoff
of the NH.sub.3 gas becomes equal to the time required for the
substrates W to pass through five compartments within the process
vessel 12, namely 5 seconds which is the time corresponding to one
lap.
[0115] FIG. 9 is a view showing one example of a relationship
between a cutoff time of a NH.sub.3 gas and film quality. The
horizontal axis in FIG. 9 indicates the cutoff time of the NH.sub.3
gas in one cycle (9 seconds) of supply and cutoff of the NH.sub.3
gas. The vertical axis in FIG. 9 indicates the WERR (Wet Etching
Rate Ratio).
[0116] The term "WERR" used herein refers to a value which is
obtained by the following: immersing a test sample into a DHF (0.5%
of hydrofluoric acid) for a predetermined time; calculating an
etching rate of the test sample etched by the DHF; immersing an
index sample having a thermally-oxidized film formed on a substrate
identical with the test sample into a DHF; calculating an etching
rate of the index sample etched by the DHF; and dividing the
etching rate of the test sample by the etching rate of the index
sample. If the value of the WERR becomes smaller, an etching
resistance grows higher and a film quality grows better.
[0117] Referring to FIG. 9, it can be noted that, if the cutoff
time of the NH.sub.3 gas in one cycle (9 seconds) of supply and
cutoff of the NH.sub.3 gas is made longer, the value of the WERR
grows smaller and the film quality grows higher.
[0118] FIG. 10 is a view showing one example of a relationship
between a cutoff time of a NH.sub.3 gas, a film thickness and
thickness uniformity. The horizontal axis in FIG. 10 indicates the
cutoff time of the NH.sub.3 gas in one cycle (9 seconds) of supply
and cutoff of the NH.sub.3 gas. The vertical axis in FIG. 10
indicates the film thickness or the thickness uniformity
(1.sigma.).
[0119] Referring to FIG. 10, it can be seen that, even if the
cutoff time of the NH.sub.3 gas in one cycle (9 seconds) of supply
and cutoff of the NH.sub.3 gas is changed, the in-plane thickness
uniformity of the substrates W does not show a great change. In
FIGS. 9 and 10, the values measured when the cutoff time of the
NH.sub.3 gas is zero indicate the values measured in a process in
which the NH.sub.3 gas is not cut off, namely a process which does
not perform a modifying operation.
[0120] Referring to FIGS. 9 and 10, it can be noted that, if the
cutoff time of the NH.sub.3 gas in one cycle of supply and cutoff
of the NH.sub.3 gas, namely the cutoff time of the reaction gas in
one cycle of supply and cutoff of the reaction gas, is made longer,
it is possible to improve the film quality while maintaining the
film thickness uniformity of the substrates W.
[0121] FIG. 11 is a view showing one example of a relationship
between a deposition rate and a film quality. In FIG. 11, reference
symbols 70a, 70b and 70c indicate the measured values at different
rotation speeds of the mounting stand 14 in a process in which the
NH.sub.3 gas is not cut off, namely a process which does not
perform a modifying operation. Reference symbol 70a indicates the
measured value in a case where the rotation speed of the mounting
stand 14 is 20 rpm. Reference symbol 70b indicates the measured
value in a case where the rotation speed of the mounting stand 14
is 10 rpm. Reference symbol 70c indicates the measured value in a
case where the rotation speed of the mounting stand 14 is 5
rpm.
[0122] Reference symbols 71a, 71b and 71c indicate the measured
values at different cutoff times of the NH.sub.3 gas in a case
where the supply and cutoff of the NH.sub.3 gas is controlled at 9
seconds per one cycle. In the measured values of reference symbols
71a, 71b and 71c, the rotation speed of the mounting stand 14 is 12
rpm. Reference symbol 71a indicates the measured value in a process
in which the NH.sub.3 gas is not cut off, namely a process which
does not perform a modifying operation. Reference symbol 71b
indicates the measured value in a case where the cutoff time of the
NH.sub.3 gas per one cycle is 2 seconds. Reference symbol 71c
indicates the measured value in a case where the cutoff time of the
NH.sub.3 gas per one cycle is 4 seconds.
[0123] As is apparent from the measured values of reference symbols
70a, 70b and 70c, even when the cutoff time of the NH.sub.3 gas is
not set, namely even when the cutoff time of the reaction gas is
not set, if the rotation speed of the mounting stand 14 is lowered,
the WERR becomes small and the film quality improves. Furthermore,
as is clear from the measured values of reference symbols 71a, 71b
and 71c, even when the cutoff time of the NH.sub.3 gas is set
longer, namely even when the cutoff time of the reaction gas is set
longer, the WERR becomes small and the film quality improves. If
the cutoff time of the NH.sub.3 gas is set longer, namely if the
cutoff time of the reaction gas is set longer, as compared with a
case where the rotation speed of the mounting stand 14 is lowered,
it is possible to improve the film quality while suppressing
reduction of the deposition rate.
[0124] Referring to FIG. 11, the measured value of reference symbol
70c and the measured value of reference symbol 71c are
approximately equal in the value of WERR to each other. However,
the measured value of reference symbol 71c is higher in the
deposition rate than the measured value of reference symbol 70c.
More specifically, the deposition rate of the measured value of
reference symbol 70c is 3.5 (A/min) while the deposition rate of
the measured value of reference symbol 71c is 5.2 (A/min). That is
to say, the deposition rate of the measured value of reference
symbol 71c is 1.5 times as high as the deposition rate of the
measured value of reference symbol 70c. Accordingly, in a case of
the measured value of reference symbol 71c, namely in a case of the
process in which the supply time of the NH.sub.3 gas per one cycle
of supply and cutoff of the NH.sub.3 gas is set at 5 seconds and
the cutoff time of the NH.sub.3 gas is set at 4 seconds, it is
possible to, while maintaining about the same film quality, make
the throughput 1.5 times as high as the throughput obtained in a
case of the measured value of reference symbol 70c, namely in a
case of the process in which the rotation speed of the mounting
stand 14 is set at 5 rpm.
Second Embodiment
[0125] FIG. 12 is a top view schematically showing a substrate
processing apparatus 10 according to a second embodiment. Except
for the points to be described below, the components of FIG. 12
designated by the same reference symbols as those of FIG. 6 have
functions identical with or similar to those of the components
shown in FIG. 6. Thus, description will be omitted on these
components.
[0126] In the present embodiment, for example, as shown in FIG. 12,
the plasma generating units 22 are respectively installed in four
consecutive regions among six substantially-identical fan-shaped
regions defined by dividing a substantially-circular plane existing
above the process vessel 12 about the axis X. Among the regions
defined by dividing the interior of the process vessel 12, the
region in which the unit U is disposed will be referred to as a
region Ad and the region in which the gate valve G is disposed will
be referred to as a region G. Furthermore, the respective regions
within the plasma generating units 22 each provided with the
antenna 22a will be referred to as a region A1, a region A2, a
region A3 and a region A4 in the named order along the clockwise
direction in FIG. 12.
[0127] As shown in FIG. 12, the division number y of the process
vessel 12 is six in the present embodiment. Thus, the control unit
60 is configured to transmit, to the driving device 24a, a control
signal for achieving a rotation speed (10 rpm) at which the
mounting stand 14 makes one revolution in the clockwise direction
for, e.g., 6 seconds. The driving device 24a rotates the mounting
stand 14 at a rotation speed at which the mounting stand 14 makes
one revolution for 6 seconds. The time x required for the mounting
stand 14 to make one revolution is 6 seconds.
[0128] Upon rotating the mounting stand 14, the substrates W are
subjected to an adsorption process and a purge process in the
region Ad. After the substrates W pass through the region G, if the
plasma of the reaction gas is generated in the regions A1 to A4,
the substrates W are subjected to a reaction process while the
substrates W pass through the regions A1 to A4. On the other hand,
if the plasma of the modifying gas is generated in the regions A1
to A4, the substrates W are subjected to a modifying process while
the substrates W pass through the regions A1 to A4 along with the
rotation of the mounting stand 14.
[0129] For example, if two is selected as the value of k in the
relational expression (1) noted above, each time when the mounting
stand 14 makes two revolutions, the time required for the mounting
stand 14 to make two revolutions and the time required in
performing one cycle of supply and cutoff of the NH.sub.3 gas are
deviated from each other by the time required for the substrates W
to pass through one compartment within the process vessel 12. In
this case, the division number y of the interior of the process
vessel 12 is 6 and the time x required for the mounting stand 14 to
make one revolution is 6 seconds in the present embodiment.
Therefore, if the mounting stand 14 makes twelve revolutions, the
cumulative value of the deviation between the time for the mounting
stand 14 to make two revolutions and the time required in
performing one cycle of supply and cutoff of the NH.sub.3 gas
becomes equal to the time required for the substrates W to pass
through six compartments within the process vessel 12, namely 6
seconds which is the time corresponding to one lap.
[0130] In the relational expression (1) noted above, if the
division number y of the process vessel 12 is 6, if the number of
seconds x of the time required for the mounting stand 14 to make
one revolution is 6, and if the value of k is 2, xk-1=11.
Therefore, it is possible to select, e.g., 6 as the m and to
select, e.g., 5 as the n within a range in which the time m+n
required in performing one cycle of supply and stop of the NH.sub.3
gas becomes equal to 11. If 6 seconds is selected as the supply
time m of the NH.sub.3 gas and if 5 seconds is selected as the
cutoff time n of the NH.sub.3 gas, the supply timing of the
NH.sub.3 gas becomes, for example, as shown in FIG. 13.
[0131] FIG. 13 is a view showing one example of a supply timing of
a NH.sub.3 gas in a case where the supply and cutoff of the
NH.sub.3 gas is controlled at 11 seconds per one cycle. Symbols
"A1", "A2", "A3", "A4", "Ad" and "G" shown in FIG. 13 designate the
region A1, the region A2, the region A3, the region A4, the region
Ad and the region G, respectively, which are defined within the
process vessel 12.
[0132] As shown in FIG. 13, the H.sub.2 gas used as one example of
the modifying gas is supplied to the regions A1 to A4 regardless of
the supply or cutoff of the NH.sub.3 gas. On the other hand, in the
case of the NH.sub.3 gas, the supply of the NH.sub.3 gas to the
regions A1 to A4 for 6 seconds and the cutoff of the NH.sub.3 gas
for 5 seconds are repeated. Since the mounting stand 14 makes one
revolution for 6 seconds, the time required for the mounting stand
14 to make two revolutions is 12 seconds. The time required in
performing one cycle of supply and cutoff of the NH.sub.3 gas is 11
(=6+5) seconds. Thus, the time required for the mounting stand 14
to make two revolutions and the time required in performing one
cycle of supply and cutoff of the NH.sub.3 gas are deviated from
each other by 1 second every two revolution of the mounting stand
14, namely by the time required for the substrates W to pass
through one compartment within the process vessel 12. If the
mounting stand 14 makes twelve revolutions, the cumulative value of
the deviation between 12 seconds which is the time required for the
mounting stand 14 to make two revolutions and 11 seconds which is
the time required in performing one cycle of supply and cutoff of
the NH.sub.3 gas becomes equal to the time required for the
substrates W to pass through six compartments defined within the
process vessel 12, namely 6 seconds which is the time corresponding
to one lap.
[0133] FIG. 14 is a view showing one example of a relationship
between a cutoff time of a NH.sub.3 gas and film quality. The
horizontal axis in FIG. 14 indicates the cutoff time of the
NH.sub.3 gas in one cycle (11 seconds) of supply and cutoff of the
NH.sub.3 gas. The vertical axis in FIG. 14 indicates the WERR.
Referring to FIG. 14, it can be noted that, if the cutoff time of
the NH.sub.3 gas in one cycle (11 seconds) of supply and cutoff of
the NH.sub.3 gas is made longer, the value of the WERR grows
smaller and the film quality grows higher.
[0134] FIG. 15 is a view showing one example of a relationship
between a cutoff time of a NH.sub.3 gas, a film thickness and
thickness uniformity. The horizontal axis in FIG. 15 indicates the
cutoff time of the NH.sub.3 gas in one cycle (11 seconds) of supply
and cutoff of the NH.sub.3 gas. The vertical axis in FIG. 15
indicates the film thickness or the thickness uniformity
(1.sigma.). Referring to FIG. 15, it can be seen that, if the
cutoff time of the NH.sub.3 gas in one cycle (11 seconds) of supply
and cutoff of the NH.sub.3 gas is made longer, the in-plane
thickness uniformity of the substrates W deteriorates slightly but
not severely.
[0135] FIG. 16 is a view showing one example of a supply timing of
a NH.sub.3 gas in a case where the supply and cutoff of the
NH.sub.3 gas is controlled at 55 seconds per one cycle. Symbols
"A1", "A2", "A3", "A4", "Ad" and "G" shown in FIG. 16 designate the
region A1, the region A2, the region A3, the region A4, the region
Ad and the region G, respectively, which are defined within the
process vessel 12.
[0136] In FIG. 16, there is illustrated a case where the division
number y of the process vessel 12 is 6, the time x required for the
mounting stand 14 to make one revolution is 6 seconds, and the
value of k is 9. In this case, xk+1=55. Therefore, it is possible
to select, e.g., 30 as the m and to select, e.g., 25 as the n
within a range in which the time m+n required in performing one
cycle of supply and stop of the NH.sub.3 gas becomes equal to 55.
In FIG. 16, there is illustrated a supply timing of a NH.sub.3 gas
in a case where 30 seconds is selected as the supply time m of the
NH.sub.3 gas and 25 seconds is selected as the cutoff time n of the
NH.sub.3 gas.
[0137] In the example shown in FIG. 16, each time when the mounting
stand 14 makes nine revolutions, the time required for the mounting
stand 14 to make nine revolutions and the time required in
performing one cycle of supply and cutoff of the NH.sub.3 gas
deviate from each other by the time required for the substrates W
to pass through one compartment within the process vessel 12. In
the example shown in FIG. 16, the division number y of the interior
of the process vessel 12 is 6 and the number of seconds x of the
time required for the mounting stand 14 to make one revolution is
6. Therefore, if the mounting stand 14 makes fifty four
revolutions, the cumulative value of the deviation between the time
required for the mounting stand 14 to make two revolutions and the
time required in performing one cycle of supply and cutoff of the
NH.sub.3 gas becomes equal to the time required for the substrates
W to pass through six compartments defined within the process
vessel 12, namely 6 seconds which is the time corresponding to one
lap.
[0138] FIG. 17 is a view showing one example of a relationship
between a cutoff time of a NH.sub.3 gas and film quality. The
horizontal axis in FIG. 17 indicates the cutoff time of the
NH.sub.3 gas in one cycle (55 seconds) of supply and cutoff of the
NH.sub.3 gas. The vertical axis in FIG. 17 indicates the WERR.
Referring to FIG. 17, it can be noted that, if the cutoff time of
the NH.sub.3 gas in one cycle (55 seconds) of supply and cutoff of
the NH.sub.3 gas is made longer, the value of the WERR grows
smaller and the film quality grows higher.
[0139] FIG. 18 is a view showing one example of a relationship
between a cutoff time of a NH.sub.3 gas, a film thickness and
thickness uniformity. The horizontal axis in FIG. 18 indicates the
cutoff time of the NH.sub.3 gas in one cycle (55 seconds) of supply
and cutoff of the NH.sub.3 gas. The vertical axis in FIG. 18
indicates the film thickness or the thickness uniformity
(1.sigma.). Referring to FIG. 18, it can be seen that, if the
cutoff time of the NH.sub.3 gas in one cycle (55 seconds) of supply
and cutoff of the NH.sub.3 gas is made longer, the in-plane
thickness uniformity of the substrates W deteriorates slightly but
not severely.
[0140] FIG. 19 is a view showing one example of a relationship
between a deposition rate and a film quality. In FIG. 19, reference
symbols 70d, 70e and 70f indicate the measured values at different
rotation speeds of the mounting stand 14 in a process in which the
NH.sub.3 gas is not cut off, namely a process which does not
perform a modifying operation. Reference symbol 70d indicates the
measured value in a case where the rotation speed of the mounting
stand 14 is 5 rpm. Reference symbol 70e indicates the measured
value in a case where the rotation speed of the mounting stand 14
is 3 rpm. Reference symbol 70f indicates the measured value in a
case where the rotation speed of the mounting stand 14 is 2
rpm.
[0141] Reference symbol 71d indicates the measured value in a
process in which the NH.sub.3 gas is not cut off, namely a process
which does not perform a modifying operation. Reference symbol 71e
indicates the measured value in a case where the cutoff of the
NH.sub.3 gas per one cycle (11 seconds) of supply and cutoff of the
NH.sub.3 gas is performed for 5 seconds. Reference symbol 71f
indicates the measured value in a case where the cutoff of the
NH.sub.3 gas per one cycle (55 seconds) of supply and cutoff of the
NH.sub.3 gas is performed for 25 seconds. In the measured values
indicated by reference symbols 71d, 71e and 71f, the rotation speed
of the mounting stand 14 is 10 rpm.
[0142] As is apparent from the measured values of reference symbols
70d, 70e and 70f, even when the cutoff time of the NH.sub.3 gas is
not set, namely even when the cutoff time of the reaction gas is
not set, if the rotation speed of the mounting stand 14 is lowered,
the WERR becomes small and the film quality improves. Furthermore,
as is clear from the measured values of reference symbols 71d, 71e
and 71f, if the cutoff time of the NH.sub.3 gas is set, namely if
the cutoff time of the reaction gas is set, the WERR becomes small
and the film quality improves. It can also be noted that, if the
ratio of the length of the cutoff time of the NH.sub.3 gas to the
length of one cycle of supply and cutoff of the NH.sub.3 gas
remains constant, the film quality and the value of the deposition
rate is substantially unchanged.
[0143] Furthermore, the measured value of reference symbol 70d and
the measured value of reference symbol 71e or 71f are approximately
equal in the value of WERR to each other. However, the measured
value of reference symbol 71e or 71f is higher in the deposition
rate than the measured value of reference symbol 70d. Accordingly,
in the case of the measured value of reference symbol 71e, namely
in a case of the process in which the supply time of the NH.sub.3
gas per one cycle (11 seconds) of supply and cutoff of the NH.sub.3
gas is set at 6 seconds and the cutoff time of the NH.sub.3 gas is
set at 5 seconds, or in the case of the measured value of reference
symbol 71f, namely in a case of the process in which the supply
time of the NH.sub.3 gas per one cycle (55 seconds) of supply and
cutoff of the NH.sub.3 gas is set at 30 seconds and the cutoff time
of the NH.sub.3 gas is set at 25 seconds, it is possible to make
the throughput higher than the throughput obtained in the case of
the measured value of reference symbol 70d, namely in a case of the
process in which the rotation speed of the mounting stand 14 is set
at 5 rpm.
Third Embodiment
[0144] FIG. 20 is a top view schematically showing a substrate
processing apparatus 10 according to a third embodiment. Except for
the points to be described below, the components of FIG. 20
designated by the same reference symbols as those of FIG. 6 have
the functions identical with or similar to those of the components
shown in FIG. 6. Thus, description will be omitted on these
components.
[0145] In the present embodiment, for example, as shown in FIG. 20,
the plasma generating units 22 are respectively installed in three
consecutive regions among five substantially-identical fan-shaped
regions defined by dividing a substantially-circular plane existing
above the process vessel 12 about the axis X. Each of the plasma
generating units 22 includes an antenna 44 configured to output
microwaves. A connection portion 44a, to which a coaxial waveguide
for supplying microwaves to the antenna 44 is connected, is
installed at the gravity center of the antenna 44.
[0146] FIG. 21 is a view showing one example of a schematic shape
of the antenna 44. The cross-sectional outline of the antenna 44
seen in the direction of the axis X is a shape with line segments
including two line segments which go away from each other as the
distance from the axis X increases. Furthermore, the
cross-sectional outline of the antenna 44 seen in the direction of
the axis X is a substantially equilateral triangular shape with
round corners. The contour of the antenna 44 includes three lines
44b and three lines 44c. Each of the lines 44b is included in each
of the sides 45a which constitute a substantially equilateral
triangle 45. Each of the lines 44c interconnects the ends of the
adjoining lines 44b with a curved line bulging outward of the
antenna 44. Each of the lines 44c is, e.g., a portion of a circle
having a specified radius. This makes it possible to suppress
concentration of stresses on a specific position within the antenna
44.
[0147] The cross-sectional outline of the antenna 44 seen in the
direction of the axis X may be a shape having rotational symmetry
(e.g., 3-fold symmetry). The connection portion 44a may be
installed at the center (e.g., the gravity center) of the antenna
44. Thus, the microwaves propagated through the coaxial waveguide
are uniformly transmitted from the upper end of the connection
portion 44a into the antenna 44. Consequently, the microwaves
transmitted into the antenna 44 are uniformly propagated through
the process vessel 12. This makes it possible to generate plasma
with increased uniformity.
[0148] According to some embodiments of the substrate processing
apparatus and the substrate processing method of the present
disclosure, it is possible to apply a plasma modifying effect to a
substrate in a cost-effective manner.
[0149] While certain embodiments have been described, these
embodiments have been presented by way of example only, and are not
intended to limit the scope of the disclosures. Indeed, the
embodiments described herein may be embodied in a variety of other
forms. Furthermore, various omissions, substitutions and changes in
the form of the embodiments described herein may be made without
departing from the spirit of the disclosures. The accompanying
claims and their equivalents are intended to cover such forms or
modifications as would fall within the scope and spirit of the
disclosures.
* * * * *