U.S. patent application number 10/736580 was filed with the patent office on 2004-07-01 for film-forming method, film-forming apparatus and liquid film drying apparatus.
This patent application is currently assigned to Kabushiki Kaisha Toshiba. Invention is credited to Ema, Tatsuhiko, Ito, Shinichi, Okumura, Katsuya.
Application Number | 20040126501 10/736580 |
Document ID | / |
Family ID | 26600895 |
Filed Date | 2004-07-01 |
United States Patent
Application |
20040126501 |
Kind Code |
A1 |
Ema, Tatsuhiko ; et
al. |
July 1, 2004 |
Film-forming method, film-forming apparatus and liquid film drying
apparatus
Abstract
Disclosed is a film-forming method, comprising dispensing from a
dispenser nozzle a coating solution, which is prepared by adding a
solid component to a solvent and controlled to be spread on the
substrate in a predetermined range, onto a target substrate to be
processed while relatively moving the dispenser nozzle and the
target substrate so as to form a liquid film on the entire surface
of the target substrate, and arranging a sucking nozzle above and
apart from the target substrate such that the sucking nozzle is not
in contact with the surface of the liquid film so as to permit the
sucking nozzle to suck the solvent vapor right under the sucking
nozzle while moving the sucking nozzle relative to the target
substrate, thereby removing the solvent from the liquid film and,
thus, forming a coated film.
Inventors: |
Ema, Tatsuhiko;
(Kawasaki-shi, JP) ; Ito, Shinichi; (Yokohama-shi,
JP) ; Okumura, Katsuya; (Tokyo, JP) |
Correspondence
Address: |
FINNEGAN, HENDERSON, FARABOW, GARRETT & DUNNER
LLP
1300 I STREET, NW
WASHINGTON
DC
20005
US
|
Assignee: |
Kabushiki Kaisha Toshiba
|
Family ID: |
26600895 |
Appl. No.: |
10/736580 |
Filed: |
December 17, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10736580 |
Dec 17, 2003 |
|
|
|
09961288 |
Sep 25, 2001 |
|
|
|
6709699 |
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Current U.S.
Class: |
427/98.4 ;
118/300; 427/99.2 |
Current CPC
Class: |
H01L 21/6715 20130101;
B05D 3/0493 20130101; H01L 21/67034 20130101; B05D 1/265 20130101;
B05D 3/0406 20130101; B05D 3/0254 20130101 |
Class at
Publication: |
427/421 ;
118/300 |
International
Class: |
B05C 005/00; B05C
015/00; B05D 001/02 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 27, 2000 |
JP |
2002-295232 |
Sep 28, 2000 |
JP |
2000-296089 |
Claims
What is claimed is:
1. A film-forming method, comprising: dispensing from a dispenser
nozzle a coating solution, which is prepared by adding a solid
component to a solvent and controlled to be spread on said
substrate in a predetermined range, onto a target substrate to be
processed while relatively moving said dispenser nozzle and said
target substrate so as to form a liquid film on the entire surface
of said target substrate; and arranging a sucking nozzle above and
apart from said target substrate such that the sucking nozzle is
not in contact with the surface of the liquid film so as to permit
said sucking nozzle to suck the solvent vapor right under the
sucking nozzle while moving the sucking nozzle relative to said
target substrate, thereby removing the solvent from the liquid film
and, thus, forming a coated film.
2. The film-forming method according to claim 1, wherein said
solvent is removed while forming said liquid film after the surface
of the liquid film formed on said target substrate is flattened and
before the liquid film is formed on the entire surface of said
target substrate.
3. The film-forming method according to claim 1, wherein the drying
treatment applied to the entire surface of said target substrate by
the relative movement between the target substrate and said suction
nozzle is carried out a plurality of times.
4. The film-forming method according to claim 3, wherein the moving
route of said suction nozzle relative to said target substrate is
the same in the drying treatment carried out a plurality of
times.
5. The film-forming method according to claim 3, wherein the moving
route of said suction nozzle relative to said target substrate in
the even number-th drying treatment is opposite to the moving route
in the even number-th drying treatment in the drying treatment
carried out a plurality of times.
6. The film-forming method according to claim 3, wherein, depending
on the drying state of said liquid film after the previous drying
treatment, the distance between said suction nozzle and the surface
of said liquid film is changed in the next drying treatment.
7. The film-forming method according to claim 1, wherein an flow of
gas is supplied by using an supply nozzle of gas flow connected to
an external gas flow supply apparatus onto the liquid film formed
on the target substrate, from which the solvent vapor is being
sucked through a suction port of said suction nozzle, so as to
remove said solvent.
8. The film-forming method according to claim 1, wherein flow of
gas is supplied onto the liquid film formed on said target
substrate from the forward region in the moving direction of said
suction nozzle relative to said target substrate.
9. A film-forming method, comprising: forming a liquid film
consisting of a coating solution prepared by adding a solid
component to a solvent on the entire surface of a target substrate
to be processed; arranging a disk plate having at least one
through-hole in the vicinity of said target substrate such that
said disk plate is not in contact with said liquid film; rotating
said disk plate so as to generate a flow of gas between said target
substrate and the lower surface of said disk plate; and bringing
the liquid film into contact with said flow of gas so as to remove
the solvent from said liquid film, thereby forming a solid phase
film consisting of said solid component on said target
substrate.
10. The film-forming method according to claim 9, wherein an flow
of gas is introduced into the clearance between said target
substrate and the lower surface of said disk plate by utilizing the
pressure reduction generated by the rotation of said disk plate in
the clearance between the target substrate and the lower surface of
the disk plate.
11. The film-forming method according to claim 9, wherein the
direction of the flow of the gas generated in the clearance between
said target substrate and the lower surface of said disk plate is
changed with time.
12. The film-forming method according to claim 11, wherein the
pressure in the clearance between said target substrate and the
lower surface of said disk plate is made different from the
pressure above the upper surface of the disk plate so as to change
with time the direction of the flow of the gas generated in the
clearance between the target substrate and the lower surface of the
disk plate.
13. The film-forming method according to claim 11, wherein the axis
of said disk plate is deviated from the axis of said target
substrate.
14. The film-forming method according to claim 13, wherein the
amount of said difference is changed with time.
15. The film-forming method according to claim 11, wherein said
target substrate is rotated in a direction opposite to the rotating
direction of said disk plate so as to change with time the
direction of said flow of gas.
16. A film-forming method, comprising: forming a liquid film
consisting of a chemical solution prepared by adding a solid
component to a solvent on the entire surface of a target substrate
to be processed; positioning a disk plate right above and apart
from said target substrate such that said disk plate is not brought
into contact with said liquid film; maintaining a reduced pressure
state in the clearance between said disk plate and said target
substrate and around said clearance; rotating said disk plate so as
to form an flow of gas in the clearance between said target
substrate and the lower surface of said disk plate; and bringing
said liquid film into contact with said flow of gas so as to remove
the solvent within said liquid film, thereby forming a solid phase
film consisting of said solid component on said target
substrate.
17. A film-forming apparatus, comprising: a dispenser nozzle
arranged to face a target substrate to be processed so as to supply
a chemical solution to said target substrate; a suction nozzle
arranged to face said target substrate for sucking a solvent vapor
on a liquid film formed on said target substrate by the supply of a
chemical solution from said dispenser nozzle; a first moving
section for relatively moving said target substrate and said
dispenser nozzle; and a second moving section for relatively moving
said target substrate and said suction nozzle.
18. The film-forming apparatus according to claim 17, further
comprising an supply nozzle of gas flow for supplying an flow of
gas to a liquid film formed on said target substrate.
19. The film-forming apparatus according to claim 17, wherein the
length of the suction port of said suction nozzle in the
longitudinal direction is larger than the diameter of said target
substrate.
20. A liquid film drying apparatus, comprising: a disk plate
arranged to face a target substrate to be processed, a liquid film
containing a solvent being formed on the surface of said target
substrate, and having at least one through-hole; a rotary driving
section for rotating said disk plate; an flow control plate
arranged to face said disk plate on the side of the open portion of
said through-hole, which is the side opposite to the side of said
target substrate; and an up-down driving section for relatively
changing the distance between said disk plate and said target
substrate and the distance between said disk plate and said flow
control plate.
21. The liquid film drying apparatus according to claim 20, further
comprising: a reduced pressure chamber having said target substrate
and said disk plate housed therein; and a vacuum pump connected to
said reduced pressure chamber for exhausting said reduced pressure
chamber.
22. The liquid film drying apparatus according to claim 20, wherein
a plurality of through-holes are formed in said disk plate, said
through-holes being arranged such that said through-holes pass
through an optional region over said target substrate in
substantially the same rate during rotation of said disk plate.
23. A liquid film drying apparatus, comprising: a disk plate
arranged to face a target substrate to be processed, a liquid film
containing a solvent being formed on the surface of said target
substrate, and having at least one through-hole; a rotary driving
section for rotating said disk plate; and an external gas flow
generator for supplying an flow of gas into said through-hole.
24. The liquid film drying apparatus according to claim 23, further
comprising: a reduced pressure chamber having said target substrate
and said disk plate housed therein; and a vacuum chamber connected
to said reduced pressure chamber for evacuating said reduced
pressure chamber.
25. The liquid film drying apparatus according to claim 23, wherein
a plurality of through-holes are formed in said disk plate, said
through-holes being arranged such that said through-holes pass
through an optional region over said target substrate in
substantially the same rate during rotation of said disk plate.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is based upon and claims the benefit of
priority from the prior Japanese Patent Applications No.
2000-295232, filed Sep. 27, 2000; and No. 2000-296089, filed Sep.
28, 2000, the entire contents of both of which are incorporated
herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a film-forming method, a
film-forming apparatus, and a liquid film drying apparatus used for
the coated film formation in the technology, for preparing a
semiconductor device in the wafer step and in the step of preparing
a mask for the optical exposure and for preparing a liquid crystal
device.
[0004] 2. Description of the Related Art
[0005] In the conventional spin coating method employed in a
lithography step, a major portion of the coating solution dripped
onto the substrate is discharged to the outside of the substrate,
and a film is formed of the remaining several percent of the
coating solution. As a result, a large amount of the coating
solution is rendered useless, and the environment is adversely
affected because a large amount of the coating solution is
discharged to the outside. An additional problem to be noted is
that, when it comes to a rectangular substrate or a disk-like
substrate having a large diameter not smaller than 300 mm,
turbulence occurs in the outer peripheral portion of the substrate,
with the result that the film thickness uniformity is rendered poor
this area.
[0006] A method for uniformly coating the entire substrate surface
with a coating solution without wastage is known. For example, a
resist is dripped from a large number of nozzles arranged to form a
row, and a gas or a liquid is blown against the film-forming
surface from behind the film-forming surface so as to obtain a
uniform film. Also, a large number of spurting holes are formed in
a rod so as to allow the resist to be dripped uniformly on the
substrate and, thus, to obtain a uniform film. Further, a spray
head provided with a large number of spurting holes for spraying a
resist and the substrate are moved relative to each other so as to
achieve a uniform coating.
[0007] In each of the conventional coating apparatuses exemplified
above, a plurality of dispensing or spraying nozzles are arranged
to form a lateral row and scanned along the surface of the
substrate so as to form a uniform film on the substrate. Also,
there is a method of forming a liquid film by scanning a single
liquid discharge nozzle on a target object to be treated in
addition to the coating method using an apparatus equipped with
these plural nozzles.
[0008] However, the conventional coating methods exemplified above
give rise to the problem that a thickness distribution of the
coated film is generated from the coating starting side toward the
coating finishing side. The difficulty is caused by the situation
that the coating starting portion and the coating finishing portion
widely differ. from each other in the waiting time between
completion of the coating solution dispensing operation and the
drying treatment. It should also be noted that, since it was
customary in the past that the step for forming the liquid film and
the drying step were carried out independently, a long time was
required for completing the coated film.
[0009] In the conventional step of drying a liquid film after
formation of the liquid film containing a solvent of, for example,
a resist film on a target substrate to be processed, employed was,
for example, a baking method in which the target substrate is
simply heated on a hot plate and a vacuum drying method in which a
reduced pressure treatment is applied within a chamber connected to
a vacuum pump.
[0010] However, in the baking method, since the evaporation of the
solvent is highly sensitive to temperature, the thickness
uniformity of the coated film was rendered poor, giving rise to a
problem in terms of the uniformity of the film thickness.
[0011] On the other hand, in the vacuum drying method under a
reduced pressure, it takes time to remove the solvent, because of
low evaporation rate in reduced pressure, leading to a problem in
terms of the low throughput. Also, the throughput is dependent on
the properties and the dispensed amount of the solvent, making it
impossible to control the processing time.
BRIEF SUMMARY OF THE INVENTION
[0012] An object of the present invention is to solve the
above-noted problems inherent in the prior art.
[0013] According to a first aspect of the present invention, there
is provided a film-forming method, comprising dispensing from a
dispenser nozzle a coating solution, which is prepared by adding a
solid component to a solvent and controlled to be spread on the
substrate in a predetermined range, onto a target substrate to be
processed while relatively moving the dispenser nozzle and the
target substrate so as to form a liquid film on the entire surface
of the target substrate; and arranging a sucking nozzle above and
apart from the target substrate such that the sucking nozzle is not
in contact with the surface of the liquid film so as to permit the
sucking nozzle to suck the solvent vapor right under the sucking
nozzle while moving the sucking nozzle relative to the target
substrate, thereby removing the solvent from the liquid film and,
thus, forming a coated film.
[0014] According to a second aspect of the present invention, there
is provided a film-forming method, comprising forming a liquid film
consisting of a coating solution prepared by adding a solid
component to a solvent on the entire surface of a target substrate
to be processed; arranging a disk plate having at least one
through-hole in the vicinity of the target substrate such that the
disk plate is not in contact with the liquid film; rotating the
disk plate so as to generate a flow of gas between the target
substrate and the lower surface of the disk plate; and bringing the
liquid film into contact with the flow of gas so as to remove the
solvent from the liquid film, thereby forming a solid phase film
consisting of the solid component on the target substrate.
[0015] According to a third aspect of the present invention, there
is provided a film-forming method, comprising forming a liquid film
consisting of a chemical solution prepared by adding a solid
component to a solvent on the entire surface of a target substrate
to be processed; positioning a disk plate right above and apart
from the target substrate such that the disk plate is not brought
into contact with the liquid film; maintaining a reduced pressure
state in the clearance between the disk plate and the target
substrate and around the clearance; rotating the disk plate so as
to form an flow of gas in the clearance between the target
substrate and the lower surface of the disk plate; and bringing the
liquid film into contact with the flow of gas so as to remove the
solvent within the liquid film, thereby forming a solid phase film
consisting of the solid component on the target substrate.
[0016] According to a fourth aspect of the present invention, there
is provided a film-forming apparatus, comprising a dispenser nozzle
arranged to face a target substrate to be processed so as to supply
a chemical solution to the target substrate; a suction nozzle
arranged to face the target substrate for sucking a solvent vapor
on a liquid film formed on the target substrate by the supply of a
chemical solution from the dispenser nozzle; a first moving section
for relatively moving the target substrate and the dispenser
nozzle; and a second moving section for relatively moving the
target substrate and the suction nozzle.
[0017] According to a fifth aspect of the present invention, there
is provided a liquid film drying apparatus, comprising a disk plate
arranged to face a target substrate to be processed, a liquid film
containing a solvent being formed on the surface of the target
substrate, and having at least one through-hole; a rotary driving
section for rotating the disk plate; an flow control plate arranged
to face the disk plate on the side of the open portion of the
through-hole, which is the side opposite to the side of the target
substrate; and an up-down driving section for relatively changing
the distance between the disk plate and the target substrate and
the distance between the disk plate and the flow control plate.
[0018] Further, according to a sixth aspect of the present
invention, there is provided a liquid film drying apparatus,
comprising a disk plate arranged to face a target substrate to be
processed, a liquid film containing a solvent being formed on the
surface of the target substrate, and having at least one
through-hole; a rotary driving section for rotating the disk plate;
and an external gas flow generator for supplying an flow of gas
into the through-hole.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0019] FIG. 1A is a plan view showing the construction of a
film-forming apparatus according to a first embodiment of the
present invention;
[0020] FIG. 1B is a cross sectional view showing the construction
of the film-forming apparatus shown in FIG. 1A;
[0021] FIG. 2 is a plan view schematically showing the construction
of a modification of the film-forming apparatus according to the
first embodiment of the present invention;
[0022] FIGS. 3A and 3B collectively show a film-forming method
according to a second embodiment of the present invention;
[0023] FIGS. 4A and 4B collectively show a film-forming method
according to a third embodiment of the present invention;
[0024] FIGS. 5A and 5B collectively show a film-forming method
according to a fourth embodiment of the present invention;
[0025] FIG. 6 schematically shows the construction of a nozzle for
drying a liquid film included in a film-forming apparatus according
to a fifth embodiment of the present invention;
[0026] FIGS. 7A and 7B schematically show collectively the
construction of a modification of the nozzle for drying a liquid
film included in the film-forming apparatus according to the fifth
embodiment of the present invention;
[0027] FIG. 8 shows a method of forming a liquid film according to
a sixth embodiment of the present invention;
[0028] FIG. 9 schematically shows the construction of an apparatus
for drying a liquid film according to the sixth embodiment of the
present invention;
[0029] FIG. 10 shows the drying method using the apparatus for
drying a liquid film shown in FIG. 9;
[0030] FIG. 11 shows the drying method using the apparatus for
drying a liquid film shown in FIG. 9;
[0031] FIG. 12 shows the drying. method using the apparatus for
drying a liquid film shown in FIG. 9;
[0032] FIGS. 13A and 13B schematically show collectively the
construction of an apparatus for drying a liquid film according to
a seventh embodiment of the present invention;
[0033] FIG. 14 shows the drying method using the apparatus for
drying a liquid film shown in FIGS. 13A and 13B;
[0034] FIG. 15 schematically shows the construction of an apparatus
for drying a liquid film according to an eighth embodiment of the
present invention;
[0035] FIG. 16 shows the problem inherent in the conventional
reduced pressure drying method;
[0036] FIG. 17 shows the drying method using the apparatus for
drying a liquid film shown in FIG. 15;
[0037] FIG. 18 schematically shows the construction of a
modification of the apparatus for drying a liquid film according to
the eighth embodiment of the present invention; and
[0038] FIG. 19 shows a drying method according to a ninth
embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0039] Some embodiments of the present invention will now be
described with reference to the accompanying drawings.
[0040] [First Embodiment]
[0041] FIG. 1A is a plan view showing the construction of a
film-forming apparatus according to a first embodiment of the
present invention, and FIG. 1B is a cross sectional view showing
the film-forming apparatus shown in FIG. 1A. The film-forming
apparatus according to the first embodiment of the present
invention is constructed to permit performing a liquid film-forming
step and a drying step simultaneously.
[0042] First of all, let us describe the construction of the
film-forming apparatus for forming a liquid film. As shown in FIGS.
1A and 1B, the film-forming apparatus comprises a resist dispenser
nozzle 102, a nozzle moving mechanism (not shown) for moving the
resist dispenser nozzle 102 in a y-direction (lateral direction),
and a target substrate moving base (not shown) on which is disposed
a target substrate 110 to be processed, which has a diameter of 200
mm. The target substrate moving base serves to move the target
substrate 110 in the x-direction.
[0043] The construction of the apparatus for performing the drying
step will now be described. As shown in FIGS. 1A and 1B, the
apparatus for performing the drying step comprises a suction nozzle
101 and a vacuum pump 103 connected to the suction nozzle 101. The
target substrate moving base referred to above in conjunction with
the liquid film-forming step is also involved in the construction
of the apparatus in the drying step.
[0044] The suction nozzle 101 includes a suction port sized at
2.times.220 mm. The length (220 mm) of the suction port 101a in the
longitudinal direction is larger than the diameter (200 mm) of the
target substrate 110. The longitudinal direction of the suction
port 101a of the suction nozzle 101 is perpendicular to the moving
direction of the target substrate. Since the length of the suction
port 101a in its longitudinal direction is larger than the diameter
of the target substrate, and the longitudinal direction of the
suction port 101a is perpendicular to the moving direction of the
target substrate, the entire surface of the target substrate 110 is
scanned by the suction nozzle 101 in accordance with movement of
the target substrate 110.
[0045] The suction nozzle 101 is positioned apart from the resist
dispenser nozzle 102 so as to permit the suction nozzle 101 to
perform its sucking operation after the surface of dripped liquid
film 111 is rendered flat. In this resist case, the surface of the
liquid film is flattened in about 30 seconds after dispensing from
the dispenser nozzle 102. Since the target substrate is moved by 48
mm in 30 seconds, the resist dispenser nozzle 102 is positioned 50
mm apart from the suction nozzle 101. Incidentally, the distance
between the suction nozzle 101 and the surface of the target
substrate 110 was set at 1 mm so as to prevent the suction nozzle
101 from touching the liquid film 111.
[0046] Now, let us describe the liquid film forming and the drying
step using the film-forming apparatus according to the first
embodiment of the present invention. The liquid film forming will
be described first. The resist dispenser nozzle 102 is reciprocated
above the target substrate 110 in the y-direction (displayed in
figure) at a speed of 1 m/sec. If the resist dispenser nozzle 102
is moved outside of the target substrate 110, the target substrate
moving base is successively moved in the x-direction so as to move
the target substrate 110. Under this condition, a chemically
amplified type DUV resist (trade name of M20G manufactured by JSR)
is successively dripped linearly from the +x side (coating starting
position) of the target substrate 100 toward the -x side (coating
finishing side) so as to form a liquid film 111 having a thickness
of 40 .mu.m on the substrate.
[0047] The drying will now be described. In 30 seconds after the
start of the dispenser operation, the suction nozzle 101 arranged
in a position remote enough to permit the dripped liquid film 111
to become flat is positioned above the target substrate 110 so as
to start the drying operation. The solvent vapor above the liquid
film 111 is sucked by the suction nozzle 101 so as to form a resist
film (coated film) 112.
[0048] The distance between the resist dispenser nozzle 102 and the
suction nozzle 101 is maintained constant, and the liquid film
forming step and the solvent drying step are carried out
simultaneously in accordance with movement of the target substrate
110.
[0049] According to the first embodiment of the present invention,
the drying step is performed immediately after the surface of the
dispensed liquid film is flattened so as to shorten the forming
time of the final resist film. Also, since the waiting time from
the dispensing of the chemical solution to the drying is
substantially constant regardless of the dispenser position, a
thickness distribution is not generated from the coating starting
side to the coating finishing side.
[0050] In the film-forming method according to the first embodiment
of the present invention, the size of the suction nozzle is not
limited to 2.times.220 mm. Also, the distance between the suction
nozzle and the surface of the target substrate to be processed is
not limited to 1 mm. Further, the arranging distance between the
suction nozzle 101 and the resist dispenser nozzle 102 is not
limited to 50 mm. Still further, the moving speed of the resist
dispenser nozzle 101 is not limited to 1 m/s. It should also be
noted that the liquid film forming method is not limited to that in
the first embodiment of the present invention. It is also possible
to use a slit type resist nozzle and to employ a meniscus coating
(which is the coating method forming a meniscus of resist solution
between the resist nozzle and the substrate). Also, in the first
embodiment of the present invention, the liquid film-forming step
and the drying step are carried out simultaneously within the
substrate surface. However, it is also possible to carry out the
liquid film-forming step and the drying step independently. It is
possible to change the operating conditions described above
appropriately in accordance with the chemical solution and the
process employed.
[0051] Also, in the first embodiment described above, a slit type
suction nozzle having a width larger than the diameter of the
target substrate is moved in one direction. Alternatively, it is
possible to use a suction nozzle smaller than the diameter of the
target substrate, as shown in FIG. 2. In this case, the target
substrate is moved from the dispensing starting side to the
finishing side while scanning the suction nozzle in a reciprocating
fashion as in the dispensing step of the resist.
[0052] [Second Embodiment]
[0053] Since the construction of the film-forming apparatus
according to a second embodiment of the present invention is
similar to that of the film-forming apparatus according to the
first embodiment described previously with reference to FIGS. 1A
and 1B, description of the film-forming apparatus is omitted. The
drying step will now be described with reference to FIGS. 3A and
3B.
[0054] In the first step, a resist solution is dripped onto the
target substrate 110 so as to form a liquid film 111, as in the
first embodiment. Then, in accordance with movement of the target
substrate 110, the suction port of the suction nozzle 101 connected
to the vacuum pump 103 is positioned above the target substrate
110, with the result that the solvent vapor above the liquid film
111 is sucked so as to start the first drying treatment.
[0055] Even after the suction nozzle 101 passed through the entire
surface of the liquid film 111 from the +x side (coating starting
side) to the -x side (coating finishing side), the solvent remained
sufficiently in the liquid film 111 and, thus, the thickness of the
liquid film 111 was 10 .mu.m (FIG. 3A). Therefore, the solvent
vapor on the liquid film 111 was successively sucked again from the
+x side (coating starting side) to the -x side (coating finishing
side) so as to carry out a second drying treatment. The thickness
of the liquid film after the second drying treatment was lowered to
5 .mu.m. The drying treatment was repeated 8 times in total so as
to dry completely the solvent in the liquid film 111, thereby
forming finally a uniform resist film 112 having a thickness of 300
nm (FIG. 3B).
[0056] According to the second embodiment of the present invention,
the drying treatment is repeated a plurality of times so as to
gradually dry the liquid film 111, with the result that the solid
component within the liquid film 111 is prevented from being sucked
so as to improve the uniformity in the thickness of the resist film
112.
[0057] In the film-forming method according to the second
embodiment of the present invention, the size of the suction nozzle
101 is not limited to 2.times.220 mm. Also, the distance between
the suction nozzle 101 and the surface of the target substrate 110
is not limited to 2 mm. Further, the moving speed of the resist
nozzle is not limited to 1 m/s. It should also be noted that the
liquid film forming method is not limited to that in the second
embodiment of the present invention. It is also possible to use a
slit type resist nozzle and to employ a meniscus coating. Also, in
the second embodiment of the present invention, the suction nozzle
was scanned 8 times. However, the number of times of scanning is
not particularly limited. It is possible to change the operating
conditions described above appropriately in accordance with the
chemical solution and the process employed.
[0058] Further, in the second embodiment of the present invention
described above, the first drying operation was performed
simultaneously with the liquid film formation. Alternatively, it is
possible to start up the drying treatment after formation of the
liquid film on the entire surface of the target substrate.
[0059] [Third Embodiment]
[0060] Since the construction of the film-forming apparatus
according to a third embodiment of the present invention is similar
to that of the film-forming apparatus according to the first
embodiment described previously with reference to FIGS. 1A and 1B,
description of the film-forming apparatus is omitted. The drying
step will now be described with reference to FIGS. 4A and 4B.
[0061] In the first step, a chemical solution is dripped onto the
target substrate 110 so as to form a liquid film 111, as in the
first embodiment. In the third embodiment, however, the chemical
solution which forming for an interlayer insulating film (JSR LKD
series manufactured by JSR) was successively dripped so as to form
a liquid film 111 having a thickness of 40 .mu.m on the entire
surface of the target substrate.
[0062] Then, in accordance with movement of the target substrate
110, the suction port of the suction nozzle 101 connected to the
vacuum pump 103 is positioned above the target substrate 110, with
the result that the solvent vapor above the liquid film 111 is
sucked so as to start the first drying treatment from the +x side
(coating starting side) to the -x side (coating finishing
side).
[0063] Even after the suction nozzle 101 passed through the entire
surface of the liquid film 111, the solvent remained sufficiently
in the liquid film 111 and, thus, the thickness of the liquid film
111 was 10 .mu.m. Also, the thickness of the liquid film tended to
increase from the suction starting side to the suction finishing
side so as to form a thickness distribution of the liquid film
(FIG. 4A).
[0064] Therefore, the solvent vapor on the liquid film 111 was
successively sucked in the opposite direction from the -x side
(coating finishing side) to the +x side (coating starting side) so
as to carry out a second drying treatment. The thickness of the
liquid film after the second drying treatment was lowered to 6
.mu.m. The reciprocating drying treatment was repeated 8 times
(four times of reciprocation) so as to dry completely the solvent
in the liquid film 111, thereby forming finally a uniform
interlayer insulating film 112 having a thickness of 500 nm (FIG.
4B).
[0065] In other words, in the even number-th drying treatment, the
suction nozzle 101 is moved relative to the target object 110 in
the direction opposite to that in the odd number-th drying
operation in the third embodiment of the present invention.
[0066] The chemical solution used in the third embodiment of the
present invention has a relatively large fluidity and, thus, the
solvent vapor is sucked from two directions so as to prevent the
thickness distribution of the liquid film from being inclined in
the sucking direction, thereby making the film thickness uniform
over the entire target substrate.
[0067] In the film-forming method according to the third embodiment
of the present invention, the size of the suction nozzle 101 is not
limited to 2.times.220 mm. Also, the distance between the suction
nozzle 101 and the surface of the target substrate 110 is not
limited to 2 mm. Further, the moving speed of the resist nozzle is
not limited to 1 m/s. Still further, the moving speed of the target
substrate is not limited to 1.6 mm/sec. It should also be noted
that the liquid film forming method is not limited to that in the
third embodiment of the present invention. It is also possible to
use a slit type resist nozzle and to employ a meniscus coating.
Also, in the third embodiment of the present invention, the suction
nozzle 101 was scanned 8 times in total (4 times of reciprocation).
However, the number of times of scanning is not particularly
limited. It is possible to change the operating conditions
described above appropriately in accordance with the chemical
solution and the process employed.
[0068] In the third embodiment of the present invention, the first
drying treatment was carried out simultaneously with the liquid
film formation. However, it is also possible to start up the drying
treatment after formation of the liquid film on the entire surface
of the target substrate.
[0069] [Fourth Embodiment]
[0070] Since the construction of the film-forming apparatus
according to a fourth embodiment of the present invention is
similar to that of the film-forming apparatus according to the
first embodiment described previously with reference to FIGS. 1A
and 1B, description of the film-forming apparatus is omitted. The
drying step will now be described with reference to FIGS. 5A and
5B.
[0071] In the first step, a chemical solution is dripped onto the
target substrate 110 so as to form a liquid film 111, as in the
first embodiment. In the fourth embodiment, however, an interlayer
insulating film (JSR LKD series manufactured by JSR) was
successively dripped so as to form a liquid film 111 having a
thickness of 40 .mu.m on the entire surface of the target
substrate.
[0072] Then, in accordance with movement of the target substrate
110, the suction port of the suction nozzle 101 connected to the
vacuum pump 103 is positioned above the target substrate 110, with
the result that the solvent vapor above the liquid film 111 is
sucked so as to start the first drying treatment from the +x side
(coating starting side) to the -x side (coating finishing side).
Incidentally, the distance between the surface of the target
substrate 110 and the suction nozzle 101 is set at 2 mm as in the
first embodiment described previously.
[0073] Even after the suction nozzle 101 passed through the entire
surface of the liquid film 111, the solvent remained sufficiently
in the liquid film 111 and, thus, the thickness of the liquid film
111 was 10 .mu.m (FIG. 5A).
[0074] Therefore, the distance between the surface of the target
substrate 110 and the suction nozzle 101 was set at 1.5 mm and the
solvent vapor on the liquid film 111 was successively sucked in the
opposite direction from the -x side (coating finishing side) to the
+x side (coating starting side) so as to carry out a second drying
treatment. The thickness of the liquid film after the second drying
treatment was lowered to 1 .mu.m.
[0075] Then, the distance between the surface of the target
substrate 110 and the suction nozzle 101 was set at 1 mm and the
solvent vapor on the liquid film 111 was successively sucked from
the -x side (coating finishing side) to the +x side (coating
starting side) so as to carry out a third drying treatment. The
thickness of the liquid film after the third drying treatment was
lowered to 500 nm.
[0076] Further, the distance between the surface of the target
substrate 110 and the suction nozzle 101 was set at 0.5 mm and the
solvent vapor on the liquid film 111 was successively sucked from
the +x side (coating starting side) to the -x side (coating
finishing side) so as to carry out a fourth drying treatment. By
these four drying treatments, the solvent within the liquid film
111 was completely dried so as to finally obtain a uniform resist
film 112 having a thickness of 300 nm (FIG. 5B).
[0077] In the fourth embodiment of the present invention, the
distance between the surface of the target substrate 110 and the
suction nozzle 101 was gradually decreased in accordance with the
thickness of the liquid film 111 so as to increase the drying
efficiency and, thus, to form a interlayer insulating film 112
having a high uniformity.
[0078] In the film-forming method according to the fourth
embodiment of the present invention, the size of the suction nozzle
101 is not limited to 2.times.220 mm. Also, the distance between
the suction nozzle 101 and the surface of the target substrate 110
is not limited to 2 mm.fwdarw.1.5 mm.fwdarw.1 mm.fwdarw.0.5 mm.
Further, the moving speed of the target substrate is not limited to
1.6 mm/sec. It should also be noted that the liquid film forming
method is not limited to that in the fourth embodiment of the
present invention. It is also possible to use a slit type resist
nozzle and to employ a meniscus coating. Also, in the fourth
embodiment of the present invention, the suction nozzle 101 was
scanned 4 times while gradually decreasing the distance between the
surface of the target substrate and the suction nozzle 101.
However, the number of times of scanning is not particularly
limited. Also, in the fourth embodiment, the suction nozzle 101 was
scanned in one direction. However, it is also possible to employ a
reciprocating scanning. The operating conditions described above
can be changed appropriately in accordance with the chemical
solution and the process employed.
[0079] In the fourth embodiment of the present invention described
above, the first drying treatment was carried out simultaneously
with formation of the liquid film. However, it is also possible to
start up the drying treatment after formation of the liquid on the
entire surface of the target substrate.
[0080] [Fifth Embodiment]
[0081] Since the construction of the film-forming apparatus
according to a fifth embodiment of the present invention is similar
to that of the film-forming apparatus according to the first
embodiment described previously with reference to FIGS. 1A and 1B,
description of the film-forming apparatus is omitted. However,
since the fifth embodiment differs from the first embodiment in the
construction of the suction nozzle 101, the construction of the
suction nozzle 101 in the fifth embodiment will now be
described.
[0082] FIG. 6 shows the construction of the suction nozzle 101
according to the fifth embodiment of the present invention. The
members of the suction nozzle 101 common with FIGS. 6 and 1 are
denoted by the same reference numerals so as to avoid an
overlapping description.
[0083] As shown in FIG. 6, a slit type supply nozzle of airflow 601
having the air blowing port connected to an air blower (airflow
supplier) 602 is connected to a slit type suction nozzle 101
(2.times.220 mm) connected to the vacuum pump 103. Incidentally, in
the following description, the structure including the suction
nozzle 101 and the airflow supply nozzle are called a liquid film
drying nozzle 600.
[0084] As shown in FIG. 6, the liquid film drying nozzle 600 was
arranged such that the airflow supply nozzle 601 and the suction
nozzle 101 were positioned on the upstream side and the downstream
side, respectively, of a scan direction. Also, the distance between
the liquid film drying nozzle 600 and the surface of the target
substrate 110 was set at 1 mm so as to prevent the liquid film
drying nozzle 600 from being brought into contact with the liquid
film 111.
[0085] The formation and the drying step of the liquid film 111
using the film forming apparatus of the particular construction
will now be described. Specifically, the resist dispenser nozzle is
reciprocated in the y-direction over the target substrate 110 at a
speed of 1 m/s. If the resist dispenser nozzle is positioned
outside the target substrate 110, the target substrate 110 is
successively moved in the x-direction. Under this state, a
chemically amplified type DUV resist (trade name of M20G
manufactured by JSR) is successively dripped from the +x side
(coating starting side) to the -x side (coating finishing side) of
the target substrate 110 so as to form a liquid film 111 having a
thickness of 40 .mu.m on the entire surface of the target substrate
110.
[0086] After formation of the liquid film 111a on the entire
surface of the target substrate 110, the target substrate 110 is
scanned relative to the liquid film drying nozzle from the coating
starting side to the coating finishing side. In this step, an
airflow is supplied from the airflow supply nozzle 601 toward the
liquid film 111b, and the airflow passing over the liquid film 111
and containing the solvent is sucked by the suction nozzle 101.
Further, the airflow is generated over the liquid film 111 between
the blowing port of the airflow supply nozzle 601 and the suction
port of the suction nozzle 101 so as to dry the solvent in the
liquid film 111 and, thus, to form a uniform resist film 112 having
a thickness of 300 nm.
[0087] In the fifth embodiment of the present invention, the drying
efficiency can be improved by adding the stream of the airflow.
Also, in the fifth embodiment of the present invention, the drying
state of the liquid film 111 is controlled by the supply of the
airflow in advance in the case of using a chemical solution having
a very large fluidity so as to prevent the suction nozzle 101 from
directly sucking the chemical solution.
[0088] In the fifth embodiment of the present invention, the liquid
film formation and the drying treatment were carried out
independently. However, it is also possible to carry out the
formation of the liquid film and the drying treatment
simultaneously with a predetermined time difference. It is also
possible to carry out the drying treatment a plurality of times
(one direction, reciprocation). Also, in the fifth embodiment of
the present invention, a single airflow supply nozzle was arranged
on one side, and a single suction nozzle 101 was arranged on the
other side. However, it is also possible to use a liquid film
drying nozzle 700 in which air blowing ports 700b are arranged on
both sides of a suction port 700a, and the suction nozzle and the
airflow supply nozzle are formed integral as shown in FIG. 7A. It
is also possible to use a liquid film drying nozzle 700 in which
suction ports 700a are arranged on both sides of an air blowing
port 700b and the suction nozzle and the airflow supply nozzle are
formed integral as shown in FIG. 7B. Incidentally, reference
numeral 103 in FIGS. 7A and 7B represents a vacuum pump, and
reference numeral 603 represents a blower.
[0089] In the film-forming method according to the fifth embodiment
of the present invention, the size of the suction nozzle 101 is not
limited to 2.times.220 mm. Also, the distance between the suction
nozzle 101 and the surface of the target substrate 110 is not
limited to 1 mm. Further, the moving speed of the resist nozzle is
not limited to 1 m/s. It should also be noted that the liquid film
forming method is not limited to that in the fifth embodiment of
the present invention. It is also possible to use a slit type
resist nozzle and to employ a meniscus coating. It is possible to
change the operating conditions described above appropriately in
accordance with the chemical solution and the process employed.
[0090] [Sixth Embodiment]
[0091] Prior to description of the drying apparatus and the drying
method of the present invention, formation of a liquid film will be
described with reference to FIG. 8. FIG. 8 shows how to form a
liquid film (resist film) in the sixth embodiment of the present
invention.
[0092] As shown in FIG. 8, a chemical solution dispenser nozzle 810
was reciprocated above a target substrate 801 in the y-direction at
a speed of 1 m/s, and the target substrate having a diameter of 200
mm was successively moved in the x-direction. Under this condition,
the chemical solution was linearly dispensed onto the target
substrate so as to form a liquid film 802 containing resist A
(solid component) on the entire surface of the target substrate
801.
[0093] Then, the solvent in the liquid film was dried by an airflow
generated by rotating a disk plate having a rotary mechanism. FIG.
9 schematically shows the construction of the liquid film drying
apparatus.
[0094] As shown in FIG. 9, a disk plate 900 comprises a first disk
901 arranged to face the target substrate 801 and having a diameter
of 250 mm and a second disk 902 arranged to face the first disk 901
with a rotary driving section 903 interposed therebetween and
having a diameter of 250 mm. An air stream introducing port 904
having a diameter of 20 mm extends through the central portions of
the first disk 901, the rotary driving section 903 and the second
disk 902. Further, a target substrate 801 having a driving section
for driving the target substrate 801 in the Z-direction is arranged
to face the first disk 901 apart from the first disk 901. Still
further, an airflow conductance control plate 905 equal in diameter
to the target substrate 801 is arranged to face the second disk 902
apart from the second disk 902.
[0095] The drying method using the liquid film drying apparatus of
the construction described above will now be described.
[0096] In the first step, the disk plate 900 was arranged above the
target substrate 801 having a liquid film 802 formed thereon with a
gap of 20 mm provided between the liquid film 802 and the disk
plate 900. Then, the distance between the airflow conductance
control plate 905 and the disk plate 900 was set at 30 mm, which
was greater than the distance of 20 mm between the target substrate
801 and the disk plate 900. Under this condition, the disk plate
900 was rotated at an angular speed of 3,000 rpm for 5 seconds.
[0097] It should be noted that, during rotation of the disk plate
900, the degree of pressure reduction in the clearance between the
target substrate 801 and the disk plate 900 is rendered greater
than that in the clearance between the disk plate 900 and the
airflow conductance control plate 905. Because of the difference in
the degree of the pressure reduction noted above, the air is
introduced into the air stream introducing port 904 from the open
portion on the side of the second disk 902 and is discharged from
the air introducing port 904 through the open portion on the side
of the first disk 901. It follows that a downstream of the air is
formed within the air stream introducing port 904, as shown in FIG.
10. As a result, an airflow from the central portion toward the
outer peripheral portion is formed in the clearance between the
target substrate and the first disk 901. Also, the liquid film 802
on the target substrate 801 is dried from the central portion
toward the outer peripheral portion by the airflow through the
clearance formed between the target substrate 801 and the first
disk 901.
[0098] Then, as shown in FIG. 11, the distance between the airflow
conductance control plate 905 and the disk plate 900 is set at 10
mm, which is smaller than the distance of 20 mm between the target
substrate and the disk plate, and the disk plate 900 is rotated
under this state at an angular speed of 3,000 rpm for 5
seconds.
[0099] In this case, the degree of pressure reduction in the
clearance between the target substrate and the disk plate is
rendered smaller than that in the clearance between the disk plate
and the airflow conductance control plate. As a result, the air is
sucked into the air stream introducing port 904 through the open
portion on the side of the first disk 901 and is discharged from
within the air stream introducing port 904 through the open portion
on the side of the second disk 902 so as to form an airflow upward
within the air stream introducing port 904 of the disk plate 900.
In this case, an airflow from the outer peripheral portion toward
the central portion is formed in the clearance between the target
substrate and the first disk 901. It follows that the liquid film
802 formed on the target substrate 801 is dried from the outer
peripheral portion toward the central portion by the airflow
through the clearance between the target substrate and the first
disk 901.
[0100] The steps described above were alternately repeated 6 times
so as to dry the solvent in the liquid film 802 for 60 seconds in
total. Finally, the lower surface of the disk plate 900 was moved
apart from the surface of the target substrate 801 so as to form a
uniform coated film (solid phase film) of resist A in a thickness
of 300 nm on the entire surface of the target substrate without
forming a thickness distribution in the flowing direction of the
airflow.
[0101] In the sixth embodiment of the present invention, the
distance between the disk plate 900 and the airflow conductance
control plate 905 was changed so as to alternately change the
direction of the airflow above the liquid film 802, thereby forming
a uniform coated film free from the thickness distribution in the
direction of the airflow.
[0102] Also, by setting appropriately the angular rotating speed of
the disk plate and the distance between the target substrate and
the disk plate, the processing time can be controlled without being
affected by the properties and the dispensed amount of the solvent
so as to improve the throughput.
[0103] Incidentally, in the liquid film drying method according to
the sixth embodiment of the present invention, the relationship
between the time and the distance between the disk plate and the
target substrate or between the disk plate and the airflow
conductance control plate is not limited to that described above.
Also, the angular rotating speed of the disk plate is not limited
to 3,000 rpm. It is possible to determine appropriately the
particular relationship and the angular rotating speed noted above
depending on the chemical solution used.
[0104] Also, in the sixth embodiment described above, the airflow
conductance control plate was moved to make the distance between
the disk plate and the target substrate larger or smaller than the
distance between the disk plate and the airflow conductance plate.
However, it is also possible to move the disk plate with the target
substrate and the airflow conductance control plate held
stationary.
[0105] Further, in the sixth embodiment of the present invention, a
scan coating method was employed for forming a liquid film.
However, it is also possible to employ other liquid film forming
methods including a spiral coating method in which a chemical
solution is dispensed spirally from the central portion toward the
outer peripheral portion and vice versa.
[0106] [Seventh Embodiment]
[0107] A liquid film of resist A was formed on the entire surface
of a target substrate as in the sixth embodiment described
above.
[0108] Then, the solvent of the liquid film was dried by using a
disk plate 1301 having a rotary mechanism, as shown in FIGS. 13A
and 13B.
[0109] As shown in FIGS. 13A and 13B, the disk plate 1301 is a disk
arranged to face a target substrate 801 and having a diameter of
120 mm. Through-holes 1303 each having a diameter .phi. of 5 mm are
spirally arranged in the disk plate 1301 at a pitch proportional to
the distance from the center of the disk plate 1301. An airflow
supplier 1302 capable of controlling the pressure at a
predetermined level of, for example, 1.5 kg/cm.sup.2, which is
higher than the atmospheric pressure, is connected to that surface
of the disk plate 1301 which is positioned on the side opposite to
the side of the target substrate 801.
[0110] As described above, through-holes 1303 are spirally arranged
in the disk plate 1301 at a pitch proportional to the distance of
the through-hole from the center of the disk plate 1301. The pitch
of the through-holes 1303 is determined to permit the same number
of through-holes per unit time to pass through a region above the
target substrate 801 regardless of the radial position of the
target substrate 801.
[0111] the through-holes are arranged on a spiral curve expressed
by Equation r=p.multidot..theta./(2.pi.) in polar coordinates (r,
.theta.). p represents the pitch of spiral curve. Relationship
between position of (n-1) th through-hole and that of n th
through-hole is expressed by Equation
r.sub.n=p.multidot.(.theta..sup.n-1+.theta..sub.p)(2.pi.).
[0112] Here, .theta..sub.p represents the angle pitch of the
through-holes.
[0113] In this case, the angle pitch of the through-hole and the
pitch of spiral curve are applied to 20.degree. and 36 mm
respectively showing on FIG. 13B.
[0114] Let us describe the drying step using the drying apparatus
shown in FIGS. 13A and 13B.
[0115] As shown in FIG. 14, the disk plate 1301 was arranged 10 mm
above the liquid film 802 and rotated at an angular speed of 2,000
rpm in the direction denoted by arrows in the drawing (the
direction opposite to the winding direction of the spiral
arrangement of the through-holes) for carrying out the drying
treatment for 60 seconds, thereby drying the liquid film. Then, the
disk plate 1301 was moved away from the surface of the target
substrate 801 so as to finally form a coated film of resist B
having a thickness of 300 nm.
[0116] In the seventh embodiment of the present invention, the
liquid film 802 formed on the target substrate 801 is kept in
contact with the air stream spurted vertically from the spirally
arranged through-holes 1303 formed in the disk plate 1301. The air
stream spurted from the through-holes is smoothly discharged
spirally toward the outer peripheral portion of the substrate so as
to dry the liquid film. A coated film having a very uniform
thickness over the entire region of the target substrate was
obtained in the process described above.
[0117] In the seventh embodiment described above, an airflow
supplier was arranged above the disk plate so as to set the air
pressure at a level higher than the atmospheric pressure. As a
result, the spurting rate of the air stream was increased so as to
improve the drying efficiency. Alternatively, it is possible for
the airflow supplier not to be arranged in some cases such that the
air stream from the through-holes is generated by only the pressure
reduction in the clearance between the target substrate and the
lower surface of the disk plate, said pressure reduction being
caused by the rotation of the disk plate. Also, it is possible to
adjust appropriately the number of through-holes formed in the disk
plate, the diameter of the through-hole, the arranging pitch of the
through-holes and the gap depending on the chemical solution
used.
[0118] Further more, it is also possible to use other gases (for
example, N2 gas etc.) for airflow supplier.
[0119] Further, in the seventh embodiment of the present invention,
a scan coating method was employed for forming a liquid film.
However, it is also possible to employ other liquid film forming
methods including a spiral coating method in which a chemical
solution is dispensed spirally from the central portion toward the
outer peripheral portion and vice versa.
[0120] [Eighth Embodiment]
[0121] A liquid film of resist A was formed on the entire surface
of the target substrate by linearly dispensing a chemical solution
on the entire surface of the target substrate having a diameter
.phi. of 200 mm while reciprocating a very small nozzle above the
target substrate in the y-direction at a speed of 1 m/s and
successively moving the target substrate in the x-direction.
[0122] Then, the liquid film was dried by using a drying apparatus
shown in FIG. 15. Specifically, FIG. 15 schematically shows the
construction of the drying apparatus according to the third
embodiment of the present invention.
[0123] As shown in FIG. 15, the target substrate 801 is arranged to
face a rotary disk plate (disk) 1501 arranged within a chamber
1502. The chamber 1502 is connected to a vacuum pump 1503 and,
thus, the pressure within the chamber 1502 can be lowered.
[0124] Let us describe the drying step using the drying apparatus
shown in FIG. 15.
[0125] In the first step, the distance between the target substrate
801 and the disk plate 1501 is set at 5 mm, and the pressure within
the chamber 1502 is lowered at a predetermined rate (-15 Torr/sec)
by operating the vacuum pump 1503. Then, when the pressure within
the chamber 1502 was lowered to reach about 2 Torr, which is the
saturation vapor pressure of the solvent, drying of the solvent was
performed by rotating the disk plate at 2,000 rpm for 30
seconds.
[0126] In the next step, the disk plate 1501 was moved away from
the surface of the target substrate 801 and taken out of the
chamber 1502 so as to finally form a coated film of resist C having
a thickness of 300 nm on the target substrate 801.
[0127] In the conventional reduced pressure drying method, the
evaporated solvent forms a turbulence under the state of the
saturation vapor pressure of the solvent so as to give rise to the
problem in the surface state and the uniformity in the thickness of
the liquid film 802, as shown in FIG. 16.
[0128] In the eighth embodiment of the present invention, however,
the solvent vapor is discharged to the peripheral portion of the
target substrate under the state of a laminar flow, with the result
that the evaporated solvent is prevented from forming a turbulence
flow under the saturation vapor pressure, as shown in FIG. 17. It
follows that it is possible to suppress the poor uniformity caused
by the turbulence flow, making it possible to obtain a coated film
of a uniform thickness.
[0129] In the eighth embodiment of the present invention, used is a
disk plate that is not provided with open portions. However, it is
also possible to use a disk plate provided with a plurality of
holes as in the seventh embodiment described previously. Also, in
the eighth embodiment of the present invention, the drying
apparatus is of a hermetic structure except that the chamber is
connected to the vacuum chamber. However, where the disk plate is
provided with holes, it is possible to arrange an gas flow supplier
1802 in the upper portion of the chamber 1502 as shown in FIG. 18
so as to carry out the drying treatment while supplying an gas into
the chamber. Also, it is possible to change appropriately the
distance between the disk plate and the target substrate, the
angular rotating speed of the disk plate, and the degree of vacuum
within the chamber depending on the chemical solution used.
Further, in the eighth embodiment of the present invention, a scan
coating method was employed for forming a liquid film. However, it
is also possible to employ other liquid film forming methods
including a spiral coating method in which a chemical solution is
dispensed spirally from the central portion toward the outer
peripheral portion and vice versa.
[0130] [Ninth Embodiment]
[0131] FIG. 19 schematically shows the construction of a drying
apparatus according to a ninth embodiment of the present invention.
The members of the apparatus common with FIGS. 19 and 9 are denoted
by the same reference numerals so as to avoid an overlapping
description.
[0132] In the first step, the disk plate was moved closer to a
position 20 mm apart from the target substrate so as to align the
axis of the target substrate with the axis of the disk plate and,
then, rotated at an angular speed of 3,000 rpm. In this step, the
target substrate was also rotated at 30 rpm in the direction
opposite to the rotating direction of the disk plate. Then, the
axis of the disk plate was moved toward the outer periphery of the
target substrate at a speed of 10 mm/s. When the axis of the disk
plate reached the outer peripheral portion of the target substrate,
the axis of the disk plate was moved toward the axis of the target
substrate at a speed of 10 mm/s. Such a reciprocating scanning
movement was repeated three times so as to carry out the drying
treatment of the solvent for 60 seconds in total, thereby forming a
resist film having a thickness of 300 nm.
[0133] The ninth embodiment differs from the sixth embodiment in
that the airflow was kept flowing downward. However, the disk plate
and the target substrate were moved relative to each other so as to
dry the solvent uniformly over the entire region of the target
substrate.
[0134] It is possible to prevent a singularity by offsetting the
axis of the disk plate and the axis of the target substrate so as
to improve the uniformity in the thickness of the coated film.
Also, it is possible to further improve the uniformity in the
thickness of the coated film by changing with time the amount of
the offset. Further, the drying efficiency can be improved by
rotating the target substrate together with the disk plate.
[0135] In the liquid film drying method according to the ninth
embodiment of the present invention, the disk plate was moved.
However, it is also possible to move the target substrate or to
move both the disk plate and the target substrate. Also, the
angular speed of the disk plate and the distance between the disk
plate and the target substrate are not limited to 300 rpm and 20
mm, respectively. Of course, it is possible to determine
appropriately the angular speed and the distance noted above
depending on the chemical solution used. Further, it is possible to
set constant the offset amount without changing the offset amount,
depending on the cases. Still further, in the ninth embodiment of
the present invention, a scan coating method was employed for
forming a liquid film. However, it is also possible to employ other
liquid film forming methods including a spiral coating method in
which a chemical solution is dispensed spirally from the central
portion toward the outer peripheral portion and vice versa.
[0136] The present invention is not limited to the embodiments
described above and can be modified in various fashions within the
technical scope of the present invention. For example, it is
possible to change the angular speed of the disk plate within a
range of between 500 rpm and 4,000 rpm and to change the distance
between the target substrate and the disk plate within a range of
between 5 mm and 30 mm, as far as the liquid film itself is
centrifugally removed from the target substrate.
[0137] Additional advantages and modifications will readily occur
to those skilled in the art. Therefore, the invention in its
broader aspects is not limited to the specific details and
representative embodiments shown and described herein. Accordingly,
various modifications may be made without departing from the spirit
or scope of the general inventive concept as defined by the
appended claims and their equivalents.
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