U.S. patent application number 09/818610 was filed with the patent office on 2001-11-01 for apparatus and method of forming liquid film.
This patent application is currently assigned to Kabushiki Kaisha Toshiba. Invention is credited to Ito, Shinichi, Okumura, Katsuya.
Application Number | 20010036512 09/818610 |
Document ID | / |
Family ID | 26495152 |
Filed Date | 2001-11-01 |
United States Patent
Application |
20010036512 |
Kind Code |
A1 |
Ito, Shinichi ; et
al. |
November 1, 2001 |
Apparatus and method of forming liquid film
Abstract
A liquid output portion is arranged above and moves relative to
a semiconductor substrate with determined film formation and
non-film-formation regions. The liquid output portion continuously
outputs a liquid in a constant amount to the substrate. Below the
liquid output portion is a liquid shut-out-portion. A liquid
controlled to spread in a constant amount is continuously output
from the liquid output nozzle to the substrate. While the nozzle
and the substrate relatively move, the liquid is supplied to a
first region, and the liquid is supplied to a second region in such
a way that the liquid supplied and spread in the second region is
in contact with the liquid supplied and spread in the first region.
Where projections and depressions are formed on the surface of the
substrate, an amount of the liquid supplied varies depending upon
the ratio between the projections and depressions.
Inventors: |
Ito, Shinichi;
(Yokohama-shi, JP) ; Okumura, Katsuya;
(Yokohama-shi, JP) |
Correspondence
Address: |
FINNEGAN, HENDERSON, FARABOW, GARRETT &
DUNNER LLP
1300 I STREET, NW
WASHINGTON
DC
20005
US
|
Assignee: |
Kabushiki Kaisha Toshiba
|
Family ID: |
26495152 |
Appl. No.: |
09/818610 |
Filed: |
March 28, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09818610 |
Mar 28, 2001 |
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09335508 |
Jun 18, 1999 |
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6231917 |
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Current U.S.
Class: |
427/9 ; 118/664;
239/101; 239/225.1; 239/97; 427/256; 427/424; 427/427.3; 427/97.3;
427/98.4; 430/271.1; 438/567; 438/778 |
Current CPC
Class: |
B05C 5/0212 20130101;
B05C 5/025 20130101; G03C 1/49845 20130101; B05B 13/04 20130101;
G03F 7/16 20130101; B05C 11/10 20130101; B05C 11/1039 20130101 |
Class at
Publication: |
427/421 |
International
Class: |
B05D 001/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 19, 1998 |
JP |
10-173021 |
Jun 30, 1998 |
JP |
10-185133 |
Claims
1. An apparatus for forming a film, comprising: a liquid output
portion arranged above a substrate in which a predetermined film
formation region and a predetermined non-film-formation region are
defined, for continuously outputting a liquid to the substrate in a
constant amount; a moving portion for relatively moving the liquid
output portion and the substrate; and a liquid shut-out portion
arranged between the liquid output portion and the substrate, for
shutting out supply of the liquid to the non-film-formation region
when at least one of the substrate and the liquid output portion is
moved and ready to supply the liquid output from the liquid supply
portion to the non-film-formation region.
2. An apparatus according to claim 1, wherein the liquid shut-out
portion comprises a liquid suction portion for sucking the liquid
output from the liquid output portion from a side of a liquid flow
and a liquid collection portion for collecting the liquid
sucked.
3. An apparatus according to claim 1, wherein the liquid shut-out
portion comprises a gas blow-out portion for blowing out a gas to a
side of the liquid output from the liquid output portion and a
liquid collection portion arranged so as to sandwich the output
liquid with the gas blow-out portion below the gas blow-out
portion, for collecting the liquid to which the gas is blown
out.
4. An apparatus according to claim 1, wherein the liquid shut-out
portion comprises a light emitting portion for emitting light for
initiating a reaction of a gas generating material; a gas blow-out
portion having the gas generating material for generating a gas
upon receipt of light controlled by the light emitting portion and
blowing out the gas generated to a side of the liquid output from
the liquid output portion; and a liquid collection portion arranged
so as to sandwich the output liquid with the gas blow-out portion,
for collecting the liquid to which the gas is blown out.
5. An apparatus according to claim 1, wherein the liquid shut-out
portion comprises a shut-out plate arranged between the liquid
output portion and the substrate, for changing a flow of the liquid
output form the liquid output portion; a shut-out plate driving
portion for loading and unloading the shut-out plate across the
flow of the liquid output from the liquid output portion; and a
liquid collection portion for collecting the liquid whose flowing
direction is changed by the shut-out plate.
6. An apparatus according to claim 1, wherein to the liquid
shut-out portion, the an image taking section is connected which is
arranged in front of a moving direction of the liquid output
portion, for taking an image data of the surface of the substrate,
and the liquid shut-out portion identifies the non-film-formation
region on the basis of the image data taken and a predetermined
pattern design data and shuts out supply of the liquid.
7. A method of forming a film comprising the steps of: outputting a
constant amount of a liquid continuously from a liquid output
nozzle to a substrate having a predetermined film formation region
and a predetermined non-film-formation region defined therein;
supplying the liquid output from the liquid output nozzle to the
film formation region on the substrate by relatively moving the
liquid output nozzle and the substrate; and collecting the liquid
by changing a direction of a flow of the liquid output from the
liquid output nozzle to a direction parallel to a direction of a
relative movement of the liquid output nozzle and the substrate by
using a liquid shut-out portion arranged between the liquid output
nozzle and the substrate and appearing standstill relative to the
liquid output nozzle, and thereby shutting out supply of the liquid
to a non-film-formation region of the substrate.
8. A method according to claim 7, wherein the non-film-formation
region is at least one of a region including an alignment mark to
be used in alignment in a light exposure step and a region of the
substrate to be processed.
9. A method according to claim 7, wherein, as the liquid, any one
of an antireflection material, a resist material, low dielectric
material, an insulating material, and a wiring material added to a
solvent is used.
10. A method for forming a film comprising the steps of: outputting
a liquid, which is controlled to be spread in a constant amount on
a substrate, continuously to the substrate from a liquid output
nozzle; moving the liquid output nozzle and the substrate,
relatively to supply the liquid to a first region on the substrate;
and supplying the liquid to a second region on the substrate by
moving the liquid output nozzle and the substrate relatively so as
to come into contact with the liquid which has been supplied from
the liquid output nozzle and spread in the first region on the
substrate.
11. A method according to claim 10, wherein, when projections and
depressions are formed on a surface of the substrate, an amount of
the liquid to be supplied onto the substrate is changed depending
upon the ratio between the projections and depressions.
12. A method according to claim 11, wherein the amount of the
liquid to be supplied onto the substrate is changed by changing an
output amount from the liquid output nozzle.
13. A method according to claim 11, wherein the amount of the
liquid to be supplied onto the substrate is changed by changing a
moving speed of the liquid output nozzle relative to the substrate
while the amount of the liquid output from the liquid output nozzle
is maintained constant.
14. A method according to claim 11, wherein the amount of the
liquid to be supplied onto the substrate is varied by changing an
amount of the liquid to be shut out by using a liquid shut-out
portion arranged between the liquid output nozzle and the
substrate.
15. A method according to claim 12, wherein the output amount is
changed by changing a deliver amount from the liquid deliver pump
arranged at an upstream side of the liquid output nozzle.
16. A method according to claim 10, wherein, in the step of
supplying the liquid to the first region on the substrate, the
liquid is supplied in a first supply direction from the inside
toward an edge of an outer periphery of the substrate while the
liquid output nozzle reciprocally is moved in a direction
perpendicular to the first supply direction, and in the step of
supplying the liquid to the second region, the liquid is supplied
in a second supply direction from the inside toward a different
edge of the periphery of the substrate so as not to overlap with
the first region by moving the liquid supply nozzle forward in the
second supply direction and simultaneously moving reciprocally in a
direction perpendicular to the second supply direction.
17. A method according to claim 10, wherein the extent of the
liquid to be spread is controlled by controlling at least one
selected from an amount of a solid matter contained in the liquid,
a viscosity and an output speed of the liquid, and a relative
moving speed of the liquid output nozzle and the substrate.
18. A method according to claim 11, wherein the ratio between
projections and depressions is determined from pattern design data
of the substrate.
19. A method according to claim 11, wherein the ratio between
projections and depressions is determined from an image of a
surface of the substrate taken by an image taking section arranged
in front of a moving direction of the liquid output nozzle.
20. A method according to claim 10, wherein as the liquid, any one
of a low dielectric material, an insulating material, an
antireflection material, a resist material, and a wiring material
added in a solvent is used.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a technique for forming a
liquid film by supplying a liquid onto a substrate to be processed,
and more specifically, to an apparatus and method of selectively
forming the liquid film on the substrate.
[0002] In a manufacturing step of the semiconductor device, a
liquid such as a resist or an SOG (Spin on Glass) solution is
coated on a substrate. In a spin-coating method which has been
conventionally used in a lithographic process to coat the liquid on
the substrate, almost all amount of the liquid supplied onto the
substrate is discarded out of the substrate and the remainder
(several %) held on the substrate is used in forming a film.
Therefore, a large amount of the liquid (such as a chemical agent)
is wasted. Furthermore, a large amount of the chemical agent is
released outside, negatively affecting the environment. In the case
where a rectangular substrate or a large-aperture disk-form
substrate (12 inches or more) is used, a turbulence is generated
around the substrate, with the result that the obtained film is not
uniform at outer peripheral portion thereof.
[0003] As a method of coating the chemical agent uniformly over the
main surface of a substrate while the chemical agent is not wasted,
Japanese Patent Application KOKAI Publication No. 2-220428
discloses a method of forming a uniform film by supplying a resist
from a plurality of nozzles arranged in line and then blowing a gas
or a liquid to the film formation surface behind the resist.
Japanese Patent Application KOKAI Publication No. 6-151295
discloses a method of forming a uniform film by splaying a resist
to a substrate from a plurality of spray holes formed in a rod.
Japanese Patent Application KOKAI Publication No. 7-321001
discloses a method of forming a uniform film by moving a spray head
having numeral spray holes for spraying a resist relative to a
substrate. All of the coating apparatuses mentioned are directed to
the formation of a uniform film by moving output nozzles or spray
nozzles arranged laterally in line in a scanning manner along a
substrate surface.
[0004] To use the chemical agent without waste, a method has been
proposed in which a liquid film is formed by supplying a liquid
from a nozzle selectively to a film formation region of the
substrate. As such a selective film formation method using a liquid
supply nozzle, known is a method using an accurate coating nozzle
(manufactured by EFD CO., Ltd.) in which output of the liquid can
be controlled in an ON/OFF manner.
[0005] In the method using the accurate coating nozzle, a liquid 13
is shut out by driving a valve such as a needle 171 or a screw 181,
which is provided within a nozzle positioned above an output port
172, as shown in FIGS. 1 and 2.
[0006] This system has a problematic phenomenon where particles are
generated by friction between the valve and the liquid when the
valve is driven, and the particles are delivered to the substrate
by being contained in a liquid supplied dropwise onto the substrate
when the valve is opened. This system has another problematic
phenomenon where pressure applied to the liquid slightly changes
immediately after the valve is opened and thereby a pulsation flow
occurs. Due to the pulsation flow, the thickness of the formed film
changes.
[0007] More specifically, if a liquid film is selectively formed on
the substrate while controlling output of the liquid by operating
the valve arranged before the output port, as described, a problem
of liquid-film contamination with the particles comes up. In
addition, if the pulsation flow occurs, the liquid film is formed
non-uniformly in thickness.
[0008] If the substrate has an uneven surface due to various
patterns formed thereon, the following problems come up.
[0009] As shown in FIG. 3, if constructs 102 are formed on a
substrate 101 and the ratio of the depressed portion is different
depending on regions of the substrate surface, the thickness of
films 103a, 103b, and 103c differs. In this case, the surfaces of
the films are not formed uniform. Then, if the structure shown in
FIG. 3 is subjected to a reflow processing, the resultant films,
for example, insulating films 104a, 104b, and 104c, can be
flattened, as shown in FIG. 4A.
[0010] However, depending upon the difference in ratio of the
depressed portion, the insulating films 104a, 104b, 104c differ in
surface level (height). Therefore, when resist patterns 106a-106c
are formed on the insulating films 104a-104c with an antireflection
film 105 interposed between them and exposed to light, some of them
are defocused. The resist patterns 106a-106c obtained after the
light exposure have a problem in that line widths thereof
drastically vary each other as shown in FIG. 4B.
[0011] In brief, as described, the spin-rotation method has a
problem in that almost all amount of liquid supplied dropwise on
the substrate is wasted. On the other hand, the method of supplying
the liquid dropwise onto the substrate has a problem in that the
formed liquid film differs in height (level) from the substrate
depending upon projections and depressions of the pattern formed on
the substrate. In other words, the formed liquid film is
non-uniform in thickness measured from the substrate surface.
BRIEF SUMMARY OF THE INVENTION
[0012] A first object of the present invention is to provide an
apparatus and method for selectively forming a liquid film on a
substrate in a uniform thickness while suppressing contamination of
the liquid film with impurities. A second object of the present
invention is to provide a method of forming a liquid film having a
flat surface even on both projections and depressions by coating a
liquid on a substrate efficiently without influence from the
projections and depressions attributed to patterns formed on the
substrate.
[0013] The present invention is constituted as described below to
attain the first object.
[0014] (1) According to the present invention, there is provided an
apparatus for forming a film, comprising:
[0015] a liquid output portion arranged above a substrate in which
a predetermined film formation region and a predetermined
non-film-formation region are defined, for continuously outputting
a liquid to the substrate in a constant amount;
[0016] a moving portion for relatively moving the liquid output
portion and the substrate; and
[0017] a liquid shut-out portion arranged between the liquid output
portion and the substrate, for shutting out supply of the liquid to
the non-film-formation region when at least one of the substrate
and the liquid output portion is moved and ready to supply the
liquid output from the liquid supply portion to the
non-film-formation region.
[0018] Preferred embodiments of constitution (1) will be described
below.
[0019] The liquid shut-out portion comprises a liquid suction
portion for sucking the liquid output from the liquid output
portion, from a side of a liquid flow, and a liquid collection
portion for collecting the liquid sucked.
[0020] The liquid shut-out portion comprises a gas blowout portion
for blowing out a gas to a side of a liquid output from the liquid
output portion and a liquid collection portion arranged so as to
sandwich the output liquid with the gas blow-out portion below the
gas blow-out portion, for collecting the liquid to which the gas is
blown out.
[0021] The liquid shut-out portion comprises
[0022] a light emitting portion for emitting light for initiating a
reaction of a gas generating material;
[0023] a light controlling portion for controlling a direction of
light emitted from the light emitting portion;
[0024] a gas blow-out portion having the gas generating material
for generating a gas upon receipt of light controlled by the light
controlling portion and blowing out the gas generated to a side of
the liquid output from the liquid output portion; and
[0025] a liquid collection portion arranged so as to sandwich the
output liquid with the gas blow-out portion, for collecting the
liquid to which the gas is blown out.
[0026] The liquid shut-out portion comprises
[0027] a shut-out plate arranged between the liquid output portion
and the substrate, for changing a flow of the liquid output form
the liquid output portion;
[0028] a shut-out plate driving portion for loading and unloading
the shut-out plate across the flow of the liquid output from the
liquid output portion; and
[0029] a liquid collection portion for collecting the liquid whose
flowing direction is changed by the shut-out plate.
[0030] Furthermore, to the liquid shut-out portion, an image taking
section is connected which is arranged in front of a moving
direction of the liquid output portion, for taking an image data of
the surface of the substrate, and the liquid shut-out portion
identifies the non-film-formation region on the basis of the image
data taken and a predetermined pattern design data and shuts out
supply of the liquid.
[0031] (2) According to the present invention, there is provided a
method of forming a film comprising the steps of:
[0032] outputting a constant amount of a liquid constantly from a
liquid output nozzle to a substrate having a predetermined film
formation region and a predetermined non-film-formation region
defined therein;
[0033] supplying the liquid output from the liquid output nozzle to
the film formation region on the substrate by relatively moving the
liquid output nozzle and the substrate; and
[0034] collecting the liquid by changing a direction of a flow of
the liquid output from the liquid output nozzle to a direction
parallel to a direction of a relative movement of the liquid output
nozzle and the substrate by using a liquid shut-out portion
arranged between the liquid output nozzle and the substrate and
stopped relatively to the liquid output nozzle, and thereby
shutting out supply of the liquid to a non-film-formation region of
the substrate.
[0035] Preferred embodiments of constitution (2) will be described
below.
[0036] The non-film-formation region is at least one of a region
including an alignment mark to be used in alignment in a light
exposure step and a region of the substrate to be processed. The
"region of the substrate to be processed" is a region to be etched
and includes a region such as an outer peripheral portion of a
wafer, on which a chip is not formed.
[0037] As the liquid, any one of an antireflection material, a
resist material, low dielectric material, an insulating material
and a wiring material added to a solvent, is used. Note that the
material to be added is not limited to the aforementioned
materials. As the liquid, a solvent containing an arbitrarily
chosen material dissolved therein, such as a metal paste, may be
used.
[0038] The present invention has the following functions and
effects by virtue of the aforementioned constitutions.
[0039] The liquid can be shut out by controlling an output amount
of the liquid from the nozzle constant and shutting out the output
liquid by the liquid shut-out portion provided below the nozzle
without generation of particles. Furthermore, it is possible to
supply the liquid uniformly to the substrate without generating a
pulsation flow by shutting out the liquid by the liquid shut-out
portion, immediately before the liquid is shut out, after the
shut-out is completed and at the time liquid supply is
reinitiated.
[0040] No valve is used, so that no pulsation flow is generated in
the liquid. As a result, it is possible to form a liquid film
having a uniform thickness. Furthermore, the supply of the liquid
to the substrate is shut out by bending the supply direction of the
liquid in a direction parallel to the moving direction of the
apparatus. When the liquid is shut out, the liquid is not scattered
out laterally from the moving direction. It is therefore possible
to form a liquid film having a uniform thickness.
[0041] Since the supply of the liquid onto the substrate is shut
out after the liquid is output from the nozzle, no particles are
generated and therefore contamination of the liquid film with
particles does not take place.
[0042] Furthermore, it is possible to reduce an amount of the
liquid to be used by shutting out the supply of the liquid from the
liquid supply nozzle by the liquid shut-out portion.
[0043] The present invention is constituted as described below to
attain the second object.
[0044] (3) According to the present invention, there is provided a
method for forming a film comprising the steps of:
[0045] outputting a liquid, which is controlled to be spread in a
constant amount on a substrate, continuously to the substrate from
a liquid output nozzle;
[0046] moving the liquid output nozzle and the substrate,
relatively to supply the liquid to a first region on the substrate;
and
[0047] supplying the liquid to a second region on the substrate by
moving the liquid output nozzle and the substrate relatively in
such a way that a liquid supplied from the liquid output nozzle and
spread on the substrate comes into contact with the liquid which
has been supplied and spread in the first region on the
substrate.
[0048] Preferred embodiments of constitution (3) will be shown
below.
[0049] When projections and depressions are formed on a surface of
the substrate, an amount of the liquid to be supplied onto the
substrate is changed depending upon the ratio between the
projections and depressions.
[0050] The amount of the liquid to be supplied onto the substrate
is changed by changing an output amount from the liquid output
nozzle.
[0051] The amount of the liquid to be supplied onto the substrate
is changed by changing a moving speed of the liquid output nozzle
relative to the substrate while the amount of the liquid output
from the liquid output nozzle is maintained constant.
[0052] The output amount is changed by changing a deliver amount
from the liquid deliver pump arranged at an upstream side of the
liquid output nozzle.
[0053] In the step of supplying the liquid to the first region on
the substrate, the liquid is supplied in a first supply direction
from an edge of an outer periphery of the substrate toward inside
while the liquid output nozzle is reciprocally moved in a direction
perpendicular to the first supply direction and simultaneously
moves in the first supply direction at predetermined pitches when
it reaches a point of return.
[0054] In the step of supplying the liquid to the second region,
the liquid is supplied in a second supply direction from another
edge of the periphery of the substrate to the inner portion thereof
so as not to overlap the first region while the liquid output
nozzle moves reciprocally in a direction perpendicular to the
second supply direction and simultaneously moves to the second
supply direction at predetermined pitches when it reaches a point
of return.
[0055] The amount of the liquid to be spread is controlled by
controlling at least one selected from an amount of a solid matter
contained in the liquid, a viscosity and an output speed of the
liquid, and a relative moving speed of the liquid output nozzle and
the substrate.
[0056] A plurality of liquid output nozzles are arranged in a
direction perpendicular to a moving direction of the liquid output
nozzle relative to the substrate, for changing amounts of the
liquid output nozzles.
[0057] The ratio between projections and depressions is determined
from pattern design data of the substrate.
[0058] The ratio between projections and depressions is determined
from an image of a surface of the substrate taken by an image
taking section arranged in front of a moving direction of the
liquid output nozzle.
[0059] As the liquid, any one of a low dielectric material an
insulating material, an antireflection material, a resist material,
and a wiring material added in a solvent, is used. Note that a raw
material to be added is not limited to the aforementioned
materials. As the liquid, a solvent containing any arbitrarily
chosen material dissolved therein, for example, a metal paste, may
be used.
[0060] The present invention has the following functions and
effects by the aforementioned constitution.
[0061] In the present invention, a liquid is supplied from a liquid
supply nozzle onto a substrate placed right below the liquid supply
nozzle. In this case, the output liquid is held on the substrate to
thereby supply only a necessary solid matter to the substrate.
Accordingly, it is possible to reduce the cost for materials. In
addition, the amount of waste materials is reduced, with the result
that adverse effects on the environment can be drastically
lowered.
[0062] Furthermore, a film having a flat surface can be formed on
both depressed portion and projecting portion by changing a
relative moving speed of the substrate and the liquid output
nozzle, a moving pitch of the nozzle or an output amount of the
liquid from the nozzle depending upon the ratio between projections
and depressions of the substrate or a desired film thickness.
[0063] Furthermore, the present invention can be attained by using
a method of shutting out the liquid supplied dropwise. To describe
more specifically, the film having a flat surface can be formed
both on a depressed portion and a projecting portion by controlling
a supply amount of the liquid by intermittently shutting out the
liquid to be supplied from the nozzle to the substrate while the
substrate and the liquid output nozzle are relatively moved
depending upon the ratio between depressions and projections of the
substrate or a desired film thickness. More specifically, the
surface of the formed film can be flattened by increasing a supply
amount of the liquid and spreading the liquid on the substrate
surface by reducing the number of shut-out operation in the
depressed portion and by decreasing a supply amount and spreading
the liquid on the substrate surface by increasing the number of
shut-out operation in the projecting portion.
[0064] Additional objects and advantages of the invention will be
set forth in the description which follows, and in part will be
obvious from the description, or may be learned by practice of the
invention. The objects and advantages of the invention may be
realized and obtained by means of the instrumentalities and
combinations particularly pointed out hereinafter.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
[0065] The accompanying drawings, which are incorporated in and
constitute a part of the specification, illustrate presently
preferred embodiments of the invention, and together with the
general description given above and the detailed description of the
preferred embodiments given below, serve to explain the principles
of the invention.
[0066] FIGS. 1A and 1B are cross-sectional views showing a
structure of a coating nozzle conventionally used;
[0067] FIGS. 2A and 2B are cross-sectional views showing another
coating nozzle conventionally used;
[0068] FIG. 3 is a cross-sectional view showing a structure of a
film formed by a conventionally used coating apparatus
[0069] FIGS. 4A and 4B are cross-sectional views showing a
structure of a film formed by subjecting the structure shown in
FIG. 3 to a reflow processing;
[0070] FIGS. 5A, 5B, 5C are cross-sectional views showing a liquid
supply unit according to a first embodiment of the present
invention;
[0071] FIG. 6 is a cross-sectional view showing a structure of a
liquid film formation apparatus using the multiple liquid supply
units;
[0072] FIGS. 7A-7D show shapes of an output port of a liquid supply
nozzle of the liquid supply unit;
[0073] FIGS. 8A-8D are cross-sectional views of an apparatus and a
substrate in a step of selectively forming a liquid film using the
liquid film formation apparatus;
[0074] FIGS. 9A and 9B are cross-sectional views showing a
structure of a liquid supply unit having a pattern identification
means;
[0075] FIGS. 10A, 10B, 10C are cross-sectional views showing a
structure of a liquid supply unit having a liquid suction portion
and a liquid collection portion;
[0076] FIGS. 11A, 11B, 11C are cross-sectional views showing a
structure of a liquid supply unit having a gas-blowing portion and
a liquid collection portion;
[0077] FIG. 12 is a cross-sectional view showing a structure of a
liquid supply unit having a gas flowing portion using a gas
generating material and a liquid collection portion;
[0078] FIG. 13 is a top-down view showing a liquid film pattern
immediately after a liquid is supplied onto the substrate by the
liquid supply unit;
[0079] FIG. 14 is a cross-sectional view showing a structure of the
liquid supply unit having a drip prevention portion;
[0080] FIG. 15 shows a layout showing a first construction of the
multiple liquid supply nozzle and liquid shut-out portion;
[0081] FIG. 16 shows a layout showing a second construction of the
multiple liquid supply nozzle and liquid shut-out portion;
[0082] FIG. 17 shows a layout showing a third construction of the
multiple liquid supply nozzle and liquid shut-out portion;
[0083] FIG. 18 shows a layout showing a fourth construction of the
multiple liquid supply nozzle and liquid shut-out portion;
[0084] FIG. 19 shows a layout showing a fifth construction of the
multiple liquid supply nozzle and liquid shut-out portion;
[0085] FIGS. 20A and 20B are cross-sectional views showing a liquid
supply unit using a shutter as the liquid shut-out portion;
[0086] FIGS. 21A-21D are cross-sectional views of an apparatus and
a substrate in a step of selectively forming a liquid film
according a second embodiment of the present invention;
[0087] FIGS. 22A and 22B are cross-sectional views of an apparatus
and a substrate in a step of selectively forming a liquid film
using a liquid supply unit having no liquid shut-out mechanism;
[0088] FIG. 23 is a top-down view of a substrate showing a state of
a film formed while a liquid is not supplied to a film formation
region;
[0089] FIGS. 24A-24C are cross-sectional views of an apparatus and
a substrate showing a structure of a liquid film formation
apparatus according to a fifth embodiment of the present
invention;
[0090] FIG. 25 is a top view of a substrate showing a state of a
film formed by the liquid film formation apparatus;
[0091] FIG. 26 is a diagram showing a structure of a coating
apparatus according to a sixth embodiment of the present
invention;
[0092] FIGS. 27A-27C are cross-sectional views of a substrate
showing a step of forming a film on a substrate using the coating
apparatus;
[0093] FIG. 28 is an illustration showing how to move a liquid
supply nozzle above a substrate;
[0094] FIG. 29 is a cross-sectional view of a liquid output portion
when a liquid is output from a liquid supply nozzle;
[0095] FIG. 30 is a diagram showing a moving speed of a liquid
supply nozzle relative to a projection/depression pattern on the
substrate;
[0096] FIG. 31A is an illustration showing how to move a liquid
supply nozzle above a substrate during liquid coating step;
[0097] FIG. 31B is a cross-sectional view of a substrate having a
defect of a liquid film coated thereon;
[0098] FIG. 32A is an illustration showing how to move a liquid
supply nozzle above a substrate during liquid coating step in which
a means is provided so as not to make the aforementioned
defect;
[0099] FIG. 32B is a cross-sectional view of the substrate shown in
FIG. 32A;
[0100] FIGS. 33A and 33B are magnified views of an outer peripheral
portion of the substrate;
[0101] FIG. 34 is a cross-sectional view showing a structure of the
coating apparatus having an image taking means;
[0102] FIG. 35 is a cross-sectional view showing a structure of a
coating apparatus having a plurality of liquid supply nozzles;
[0103] FIG. 36 is diagram showing an output amount (drip speed) of
a liquid supply nozzle to a projection/depression pattern on the
substrate; and
[0104] FIG. 37 is a cross-sectional view of a substrate coated by
the coating apparatus of FIG. 35.
DETAILED DESCRIPTION OF THE INVENTION
[0105] Embodiments of the present invention will be explained with
reference to the drawing.
[0106] First Embodiment
[0107] This embodiment relates to a method of forming an
antireflection film. In this embodiment, we will explain a method
of forming a film selectively on a substrate except a
non-film-formation region (an alignment mark, an outer edge portion
of the substrate, or non-patterning region where a chip is not
formed).
[0108] First, we will explain a structure of a liquid film
formation apparatus for forming a liquid film by supplying a liquid
selectively onto a substrate to be processed.
[0109] FIGS. 5A, 5B, 5C are cross-sectional views showing a
structure of a liquid supply unit according to a first embodiment
of the present invention.
[0110] As shown in FIG. 5A, a substrate 15 is mounted on a holder
(not shown). A liquid supply unit 10 for selectively forming a
liquid film on the substrate is positioned right above the
substrate 15. The liquid supply unit 10 has a liquid supply nozzle
11 and liquid suction portions 12a, 12b. The liquid supply nozzle
11 is responsible for outputting a liquid 13 to the substrate 15.
The liquid suction portions 12a, 12b suck the liquid 13 output from
the liquid supply nozzle 11, so that the supply of the liquid 13
from the nozzle 11 to the substrate 15 is shut out. In short, the
liquid 13 is sucked by the liquid suction portions 12a, 12b and
collected from the suction port.
[0111] The liquid supply unit 10 has a unit moving portion 16 for
moving the liquid supply unit 10. While the liquid supply unit 10
is moved by the unit moving portion 16, the liquid 13 is allowed to
output from the liquid supply nozzle 11 to the substrate 15. In
this manner, a liquid film 14 is formed on the substrate 15.
[0112] Incidentally, two liquid suction portions 12a, 12b are
arranged in parallel to the moving direction of the liquid supply
unit 10 and so as to sandwich the liquid 13 supplied dropwise. If
the liquid supply unit 10 moves, for example, to the right-hand
side of the paper, the liquid is sucked by the liquid suction
portion 12a, which is positioned at the back side of the moving
direction as shown in FIG. 5B. In this manner, the supply of the
liquid 13 to the substrate 15 is shut out. On the other hand, the
liquid supply unit 10 moves to the left-hand side of the paper, the
liquid 13 is sucked by the liquid suction portion 12b positioned at
a back side of the moving direction. In this manner, the supply of
the liquid 13 to the substrate 15 is shut out.
[0113] Now, referring to FIG. 6, we will explain a liquid film
formation apparatus 20 having a plurality of liquid supply units so
as to form a film a selectively on a broad region on the substrate
at one time. FIG. 6 is a cross-sectional view of the apparatus 20
viewed from a position in front of the moving direction. The liquid
supply units independently have a liquid supply nozzle 111 & a
liquid suction portion 121, a nozzle 112 & a suction portion
122, a nozzle 113 & a suction portion 123, a nozzle 114 & a
suction portion 124, a nozzle 115 and a suction portion 125, a
nozzle 116 & a suction portion 126, and a nozzle 117 & a
suction portion 127. These liquid supply units are arranged in the
direction perpendicular to the moving direction thereof. Using the
liquid film formation apparatus 20 having such liquid supply units,
a film is formed selectively on a film formation region 21 and a
non film-formation region 22 by independently controlling
operations (suction) of the liquid suction portions 121-127
corresponding to liquid supply nozzles 111-117.
[0114] Individual nozzles 111-117 are arranged at intervals of 100
.mu.m. The intervals of individual nozzles 111-117 may be
arbitrarily varied depending upon an output region. Furthermore,
shape of ports of these nozzles 111-117 is an ellipse having a
short axis (20 .mu.m).times.a long axis (40 .mu.m) as shown in FIG.
7A (in this case, the long axis is positioned in the same direction
as the nozzle arrangement direction). As the shape of ports of the
nozzles 111-117, a circle (FIG. 7B), a rectangle (FIG. 7C), right
square (FIG. 7D) may be used.
[0115] Next, referring to FIGS. 8A-8D, we will explain how to
selectively form a liquid film by use of the liquid film formation
apparatus 20 shown in FIG. 6. Note that, in FIGS. 8A-8D, the
apparatus is moved to the fore side of the paper. Hereinbelow, we
will explain the case where an antireflection film is formed by
coating a solution containing an antireflection material on the
substrate. To obtain the antireflection film having a film
thickness of 0.055 .mu.m, a solid matter of antireflection material
contained in a solvent is adjusted at 0.5% and a moving speed of
the liquid film formation apparatus is set at 100 mm/sec.
[0116] A film is formed by moving the liquid film formation
apparatus 20 reciprocally in a line (row) direction and
simultaneously in a row (line) direction with respect to the
substrate 15. In the case where non film-formation region is not
included, a whole amount of an antireflection solution 411 output
from the liquid supply nozzles 111-117 is supplied to the substrate
15 and spread over the substrate 15 to thereby form a liquid film
412.
[0117] When the film formation apparatus 20 comes immediately
before an alignment mark 42, the following operation is performed.
As shown in FIG. 8B, when the liquid suction portions 123, 126
corresponding to the liquid supply nozzles 113, 116, which are
positioned immediately above the alignment marks 42, initiate
suction of the antireflection solution 411, supply of the
antireflection solution 411 onto the alignment mark 42 is shut out.
The suction of the antireflection solution 411 is continued until
the film formation apparatus 20 exceeds over the alignment mark 42.
The presence and absence of the alignment mark 42 is identified
based on pattern design data of the substrate 15.
[0118] In this embodiment, when the liquid discharged from the
liquid supply nozzles 111-117 is shut out by the liquid suction
portions 121-127, no pulsation flow is generated in the liquid. It
is therefore possible to form a liquid film uniform in thickness.
Furthermore, when the flowing direction of the liquid is bent in a
direction in parallel to the moving direction of the apparatus, the
supply of the liquid to the substrate is shut out. When the liquid
is shut out, the liquid does not scatter laterally with respect to
the moving direction. It is therefore possible to form the liquid
film uniform in thickness.
[0119] In this embodiment, the supply of the antireflection
solution is not shut out by mechanically closing the nozzle ports.
Therefore, particles are not generated, with the result that the
antireflection solution will not contaminated with the
particles.
[0120] When the apparatus exceeds over the alignment mark 42, the
suction by the liquid suction portions 123, 126 corresponding to
the nozzles 113, 116 are terminated as shown in FIG. 8C, and then
the supply of the antireflection solution 411 is initiated from the
nozzles 113, 116 to the substrate 15.
[0121] Thereafter, after an antireflection solution film 412 is
selectively formed on the film formation region of the substrate
15, a solvent is vaporized by baking to form the antireflection
film 413 having a desired film thickness, as shown in FIG. 8D. In
the same manner as in the formation of the antireflection film 413,
a resist film is formed selectively on the substrate except the
alignment mark and the region outside the chip formation region. A
resist film is formed in a film thickness of 0.3 .mu.m by setting a
solid matter of the resist material at 1.5% and a moving speed of
the film formation apparatus 20 at 50 mm/sec.
[0122] In this embodiment, it is designed that the antireflection
film and the resist film are not formed on the alignment mark.
Therefore, the accuracy in alignment can be dramatically improved
during the light exposure. The improvement of accuracy in alignment
influences devise designing, with the result that difference in
electric properties depending upon devices can be reduced and a
chip area can be further reduced.
[0123] In this case, diluted solutions of the antireflection
material and the resist material are used as the liquid, however,
the liquid is not limited to these. As the liquids to be used in
the present invention, solutions containing a conductive material,
an interlayer insulating material, and a wiring material, and
molten solution of these materials themselves, may be used. The
liquid used herein may include a thinner-diluted solution or a
molten raw material.
[0124] The non film-formation region such as the alignment mark is
identified with reference to a pattern design data or a pattern
image taken by a pattern identification means 51a, 51b as shown in
FIGS. 9A, 9B. The pattern identification means 51a, 51b are set in
front of the moving direction (indicated by an arrow in the figure)
of the liquid supply nozzle 11 to take a pattern present in the
front of the moving direction. The pattern identification means 51b
is used when the apparatus moves in a backward direction. The
pattern identification means 51a (51b) consists of a CCD camera, an
image fiber, or the like.
[0125] In the aforementioned embodiment, the liquid is directly
sucked by a liquid shut-out portion. However, the present invention
is not limited to this. For example, a liquid film formation
apparatus 60 may be used which has liquid suction portions 62a, 62b
and liquid collection portions 63a, 63b, as shown in FIG. 10A. The
liquid collection portions 63a, 63b are provided below the suction
portions 62a, 62b, respectively, so as to sandwich the liquid 13
between them. In the film formation apparatus 60 of the present
invention, the liquid 13 supplied dropwise is attracted to the
suction portion 62a (or 62b) by suction and the attracted liquid 13
is collected by the liquid collection portion 63a (or 63b) (FIG.
10B and FIG. 10C).
[0126] Alternatively, a liquid film formation apparatus 70 may be
used. In the apparatus 70, gas is blown to the liquid 13 from gas
spray portion 72a (72b) to change the direction of the liquid 13 to
be supplied dropwise and the liquid 13 is collected by the liquid
collection portion 63a (63b), as shown in FIGS. 11A, 11B, 11C. FIG.
11A is a cross-sectional view of the film formation apparatus in
the case where the supply of the liquid 13 is not shut out. FIG.
11B is a cross-sectional view of the film formation apparatus in
the case where the supply of the liquid 13 is shut out by spraying
a gas from the gas spray portion 72a. FIG. 11C is a cross-sectional
view of the film formation apparatus in the case where the supply
of the liquid 13 is shut out by spraying a gas from the gas spray
portion 72b.
[0127] Note that when the direction of the liquid 13 to be supplied
dropwise is changed by blowing a gas, it is desirable that no
obstacle be present in the gas spray direction. In the case where
two gas spray portions 72a, 72b are provided and used respectively
in the cases of the forward movement and the backward movement of
the nozzle, it is desirable that the gas spray portions 72a, 72b be
set at different levels in height.
[0128] As another method for shutting out the liquid supply by
changing the direction of the liquid to be supplied dropwise by gas
spray, a liquid film formation apparatus as shown in FIG. 12 may be
used. In this method, light is exposed to a gas generating material
to induce a reaction and the gas generated from the reaction is
blown out to the liquid output from the nozzle. In this manner, the
direction of the liquid supplied dropwise is changed to shut out
the supply of the liquid to the substrate.
[0129] As shown in FIG. 12, a substrate 15 is mounted on a holder
(not shown) horizontally. On the right above the substrate 15 are
arranged a liquid supply unit 80 for forming a liquid film
selectively on the substrate 15 and a unit moving portion 16 for
moving the liquid supply unit 80. The liquid supply unit 80 has a
liquid supply nozzle 11, a light emitting unit (a light source
portion 82, a light reflecting portion 83, a gas blow out portion
84, liquid collection portions 63a, 63b.
[0130] The liquid supply nozzle 11 outputs the liquid 13 to the
substrate 15. The light source portion 82 emits light for inducing
the reaction of the gas generating material provided in the gas
blow out portion 84. The light reflecting portion 83 reflects the
light emitted from the light source portion 82. The light
reflecting portion 83 thus controls the direction of the light and
guides the light to the gas blow out portion 84. The gas blow out
portion 84, for example, consists of a quartz substrate 84a and a
gas generating material 84b mounted on the upper surface of the
quartz substrate 84a. As the gas generating material 84b, for
example, nitrocellulose is used. The gas generating material 84b
mounted on the gas blow-out portion 84 generates gas through the
reaction induced upon the receipt of the light emitted from the
light emitting portion 82. The gas changes the direction of the
liquid 13 to be supplied dropwise from the liquid supply nozzle 11.
The liquid 13 changed in supply direction is collected by the
liquid collection portion 63b.
[0131] As the light emitting unit, the light source portion 82 may
be used alone. As the gas blow out portion 84, a rotation disk form
and a tape form may be used other than the aforementioned form. As
the quartz substrate 84a, any material other than quartz is used as
long as it absorbs light from the light emitting portion 82 in a
low amount. For example, cellophane may be used.
[0132] In the liquid supply unit 80, when the liquid is supplied
continuously to the substrate 15, the following operation is
performed. First, the liquid 13 is output from the liquid supply
nozzle 11 to the substrate 15. While the output is continued, the
liquid supply nozzle 11 is moved by the unit moving portion 16.
Since the liquid 13 is thus supplied to the substrate 15 in a
constant amount, a liquid film 14 is formed.
[0133] On the other hand, when the supply of the liquid 13 to the
substrate 15 is shut out, the following operation is performed.
Note that FIG. 12 shows the case where the liquid supply nozzle 11
moves to the left hand side of the paper. First, light is emitted
from the light emitting portion 82. The direction of the light is
controlled by the light reflecting portion 83 and irradiated to the
gas generating material 84b of the gas blow out portion 84. In the
gas blow out portion 84, the reaction of the light-exposed gas
generating material 84b is initiated to generate a gas. The gas
generated by the gas blow-out portion 84 is blown out to the liquid
13 output from the liquid supply nozzle 11. In this manner, the
liquid 13 is changed in supply direction and collected by the
liquid collection portion 63b. As a result, the supply of the
liquid 13 from the liquid supply nozzle 11 to the substrate 15 is
shut out. In this case, if the gas blow out portion is arranged in
an opposite direction with respect to the nozzle 11, the liquid 13
may be collected by the liquid collection portion 63a.
[0134] FIG. 13 is a top view of a liquid pattern formed immediately
after the liquid is output onto the substrate 15 in the liquid film
formation apparatus. The liquid pattern 14a shown in FIG. 13 is a
coating portion formed by continuously supplying the liquid 13.
Furthermore, the discrete-from liquid pattern 14b is a coating
portion obtained by alternating no liquid supply (space) at the
time the gas is generated at the gas blow out portion 84 and the
liquid supply (pattern 14b) when the gas is not generated.
[0135] The liquid pattern 14a is desirably coated on the region
having patterns with low density on the substrate, whereas the
liquid pattern 14b is desirably coated on the region having
patterns with high density on the substrate. If the coating is made
in this manner, it is possible to form the liquid film 14 having a
flat surface both on projections and depressions regardless of
projections and depressions ascribed to the patterns formed on the
substrate.
[0136] Furthermore, in the case there the liquid is collected by
the liquid collection portions 63a, 63b, the liquid drips sometimes
fall from the edges of the liquid collection portions 63a, 63b to
attach onto the substrate 15. To prevent this, drip guards 85a, 85b
are provided below the liquid collection portions 63a, 63b,
respectively, as shown in FIG. 14. In this manner, the liquid
spilled out from the edge of the liquid collection portions 63a,
63b is collected by the drip guards 85a, 85b. Note that the edges
of the drip guards 85a, 85b are arranged at positions outside the
liquid collection portions 63a, 63b. The drip guards 85a, 85b are
also adapted to FIGS. 9A, 9B, 10A-10C, 11A-11C, 12, 20A, 20B types'
unit.
[0137] In the aforementioned liquid supply unit, when the liquid
supply is shut out, the supply direction of the liquid is changed
toward the backward side of the moving direction, however, the
supply direction may be changed to the forward side of the moving
direction. However, when the nozzle is moved at a high speed, the
liquid supplied drowse flows backward. Therefore, if the liquid is
supplied in the backward to the moving direction, it is easier to
capture the liquid at the rearward from the nozzle.
[0138] Accordingly, when the nozzle is moved in a high speed, it is
desirable that liquid shut-out portions 91a, 91b be arranged for
each of liquid supply nozzles 11 in the nozzle moving direction
(forward and backward) as shown in the layout of the liquid supply
unit of FIG. 15 and they be selectively used depending upon the
moving direction. Note that the liquid shut-out portions 91a, 91b
are the designation for collectively referring to the liquid
suction portions 12a, 12b, the liquid suction portions 62a, 62b,
liquid collection portions 63a, 63b, the gas spray portions 72a,
72b, liquid collection portions 63a, 63b, and the gas blow-out
portion 84, liquid collection portion 63b. On the other hand, when
the nozzle 11 moves at a low speed, the liquid may be collected
either at the forward or at the rearward. In this case, a single
liquid shut-out portion and a single liquid collection portion are
provided, so that the liquid may be collected by the same liquid
collection portion both in the forward direction and the backward
direction.
[0139] Now, we will explain the case where a single liquid shut-out
portion is provided per nozzle with reference to the layouts of the
liquid supply unit shown in FIGS. 16-19. The like reference
numerals are used in FIGS. 16-19 to designate the like structural
elements in FIG. 15 and any further explanation is omitted.
[0140] The liquid supply unit shown n FIG. 16 is constructed by
arranging the liquid shut-out portion 91 at one of the moving
directions of the liquid supply nozzle 11. When the liquid supply
unit of this type is used, the liquid may be supplied to the
substrate only in the forward direction or in the backward
direction.
[0141] In the liquid supply unit shown in FIG. 17, the liquid
shut-out portion 91 is arranged at one of the moving directions of
the liquid supply nozzle 11. The liquid supply unit of this type is
effective in the case where the liquid shut-out portion 91 has a
function of shutting out the liquid supply by spraying a gas. In
the liquid supply unit, since the liquid shut-out portions 91 are
arranged alternately, the mutual interference of the gases sprayed
out can be prevented.
[0142] The liquid supply units shown in FIGS. 18, 19 are another
type units, in which adjacent nozzles 11 and liquid shut-out
portions 91 are appropriately arranged at a shorter distance. Thus
the liquid flows output from the adjacent nozzles are narrowed. In
the liquid supply unit shown in FIG. 18, the liquid shut-out
portions 91 facing the corresponding liquid supply nozzles 11, are
arranged in a manner that they sandwich the liquid supply nozzles
11 aligned in two rows so as not to overlap each other. The liquid
supply unit shown in FIG. 19, the liquid supply nozzles 11 facing
the corresponding the liquid shut-out portions 91, are arranged in
a manner that they sandwich the liquid shut out portions 91
arranged in two rows so as not to overlap each other.
[0143] In the meantime, as shown in FIGS. 20A, 20B, the liquid 13
may be shut out by a shutter 141. The case where the liquid 13 is
supplied to the substrate 15 is shown in FIG. 20A. The case where
the supply of the liquid 13 to the substrate 15 is shut out is
shown in FIG. 20B. In the liquid supply unit, the shutter 141
having a trapezoidal cross section is used. When the supply of the
liquid 13 is shut out, the shutter 141 is inserted into the line
through which the liquid 13 output from the nozzle 11 passes, from
the upstream of the moving direction. Any shape of the shutter 141
may be inserted in any direction as long as the liquid 13 is not
scattered on the substrate 15 by the insertion and the liquid 13
does not drip down from the back of the shutter 141.
[0144] When the nozzle is moved at a high speed, the liquid flows
backward in the moving direction. Therefore, the shutter is
inserted in the same direction as the flow direction of the liquid.
When the shutter is inserted in the opposite direction, the liquid
is scattered to smear the surface of the film formation
substrate.
[0145] Second Embodiment
[0146] In this embodiment, we will explain the method in which a
film is previously formed by using a solvent which rejects a
solution of an antireflection material, on a non-film-formation
region (alignment mark, non chip formation region in the outer
periphery of the substrate) and thereafter, a film of the
antireflection material is formed.
[0147] FIGS. 21A-21D are cross-sectional views of an apparatus and
substrate showing the steps of selectively forming a liquid film
according to a second embodiment of the present invention. First,
as shown in FIG. 21A, a substrate 15 is prepared having an
alignment mark 42 formed on the surface thereof and horizontally
held on the holder (not shown).
[0148] Subsequently, as shown in FIG. 21B, a liquid supply unit 10
(shown in FIGS. 5A-5C) having a single liquid supply nozzle 11 is
moved reciprocally in the line (row) direction and simultaneously
in the row (line) direction with respect to the substrate 15. In
this manner, solvent, EEP 151 is supplied drowse selectively in a
non antireflection film formation region, in other words, in a
region containing the alignment mark 42. The shape of the port of
the nozzle 11 used herein is a rectangle of 10 .mu.m.times.40 .mu.m
(a long side of the rectangle is arranged in perpendicular to the
moving direction of the nozzle).
[0149] Subsequently, a film of an antireflection solution 411 is
selectively formed by using the liquid film formation apparatus 20
shown in FIG. 6 having a plurality of liquid supply nozzles 111-117
and the liquid suction portions 121-127. At this time, as shown in
FIG. 21C, supply of the antireflection solution 411 is shut out to
the region containing the alignment mark 42 of the substrate 15. In
practice, a solid matter of the antireflection material contained
in the solvent was set at 0.5%. The moving speed of the liquid
supply unit was set at 100 mm/sec. As a result, the antireflection
liquid film 412 was formed at a film thickness of 0.055 .mu.m.
[0150] After the film is selectively formed, the baking is
performed. As a result, solvent EEP 151 is vaporized and disappears
as shown in FIG. 21D. In addition, the solvent contained in the
antireflection liquid film 412 is vaporized to thereby form an
antireflection film 41 accurately in a region except the alignment
mark region.
[0151] Subsequently, the EEP solvent was previously coated
selectively on a non film formation region except the alignment
mark region and the region outside the chip formation region in the
same manner as in the case where the antireflection film 41 was
formed. Thereafter, a solution containing a resist material
dissolved in solvent EL was coated on the film-formation region of
the substrate 15. The solid matter of the resist solution was 1.5%.
The liquid supply unit was moved at a moving speed of 50 mm/sec. As
a result, a resist film was formed in a film thickness of 0.3
.mu.m.
[0152] In this embodiment, since the antireflection film and the
resist film were not formed on the alignment mark, accuracy in the
alignment at the time of light exposure was dramatically improved.
Furthermore, the improvement in alignment accuracy influences
device designing, difference in electric properties depending upon
the devices was reduced and the chip area was further reduced.
[0153] Films may be formed from diluted solutions of the
antireflection material and the resist material in the following
steps. After the step shown in FIG. 21B, a resist solution 1611 is
supplied drowse and uniformly on the substrate 15 by using a liquid
film formation apparatus 160 having no liquid shut-out mechanism,
without supplying the antireflection solution or the resist
solution selectively, as shown in FIG. 22A. In this manner, a
resist liquid solution 1612 is formed.
[0154] Of the resist solution 1611 supplied drowse and uniformly on
the substrate 15, the resist solution 1611 supplied drowse on the
EEP 151 slides down along the surface of the EEP 151 to the
periphery of the EEP 151. Thus, after the resist liquid film 1612
using an EL solvent was coated and subjected to baking, EEP 151 is
vaporized and disappeared, and simultaneously, the EL solvent
contained in the resist liquid film 1612 was vaporized. As
described in the foregoing, the resist film 161 was formed
selectively in the region except on the alignment mark 42 of the
substrate 15.
[0155] The resist film 161 is thicker near the non film formation
region of the alignment mark 42. However, the region was not
required to form a pattern contributing to the device, the
processing accuracy was not affected.
[0156] Third Embodiment
[0157] In this embodiment, we will explain the case where the
present invention is applied to a wiring pattern. A substrate of 3
mm thick made of AlNx is horizontally placed on a holder. A liquid
film formation apparatus is set above the substrate.
[0158] In this embodiment, a wiring pattern is formed by using the
liquid film formation apparatus having a plurality of liquid supply
units (shown in FIGS. 10A-10C) arranged in line. The liquid supply
units are arranged in the direction perpendicular to the moving
direction of the apparatus. Since each of liquid suction portions
of the liquid supply units is controlled independently, the liquid
can be coated selectively on a film formation region or a non
film-formation region.
[0159] Note that the liquid supply nozzles of the liquid supply
unit used were arranged at intervals of 100 .mu.m. The shape of the
nozzle port was a square of 40 .mu.m.times.40 .mu.m. While the
apparatus was reciprocally moved in a line (row) direction and
simultaneously in a row (line) direction with respect to the
substrate. In this manner, a liquid film was formed.
[0160] The apparatus was moved above the substrate along the
illustration of wiring to form the film. The apparatus was moved at
a constant speed when it moved along a line or a curve. Curvature
was given to a point of return of the pattern, so that the moving
speed of the nozzle was not changed.
[0161] A film was formed by controlling the amount of a silver
paste (serving as a wiring material) to be output from each of
liquid supply nozzle per unit time. The liquid was sucked by the
liquid suction portion in a non-wiring formation region on the
basis of wiring design data. In this way, the silver paste was
prevented from being supplied to the substrate. After all wiring
patterns were formed, a solvent was vaporized by subjecting the
substrate to baking at a temperature of 400.degree. C. to fix or
fit the wiring pattern.
[0162] Using the wiring pattern formed in this embodiment as a
heater (soaking plate: AlNx, a heater material: silver) by
supplying electric power thereto, a plate-form substrate was heated
to 150.degree. C. As a result, the temperature uniformity was
.+-.0.2.degree. C. When a wiring pattern formed by silk-screen
printing conventionally used (coating spots were present in a
printing direction) was used as a heater by supplying electric
power, the temperature differs within .+-.1.degree. C. since
difference in resistance was large. Compared to the conventional
heater, the uniformity in temperature was dramatically improved in
this embodiment as mentioned above. Furthermore, when the wiring
pattern formed by using a conventionally-employed liquid supply
nozzle, which was characterized by controlling the output operation
within the nozzle, was used as a heater by supplying power thereto,
temperature differed within .+-.0.6.degree. C. since a resistance
value was varied by influence of pulsation flow. Compared to this,
the uniformity of temperature was dramatically improved in the
wiring pattern of this embodiment.
[0163] Fourth Embodiment
[0164] In this embodiment, we will explain the case where the
present invention is applied to formation of a wring pattern.
[0165] A substrate of 3 mm in thick made of AlNx is placed
horizontally on a holder. A liquid supply nozzle is arranged above
the substrate.
[0166] In this embodiment, a wiring pattern is formed by using the
liquid film formation apparatus having a plurality of liquid supply
units (as shown in FIGS. 20A, 20B) arranged linearly. The liquid
supply units are arranged in a direction perpendicular to the
moving direction of the apparatus. Each of the shutter of the
liquid supply units is controlled independently to thereby coat a
liquid selectively to a film formation region or a non film
formation region. The shape of the port of the liquid supply nozzle
used herein was a square of 40 .mu.m.times.40 .mu.m.
[0167] Using such a film formation apparatus, a wiring pattern was
formed in the same manner as in the third embodiment. The apparatus
was moved on the basis of wiring design data. A shutter was
released to supply a liquid to the substrate at an initial point of
the wiring and inserted to terminate the supply at an end point
thereof. Likewise, the shutter was inserted in the region in which
no wiring is formed, so that a silver paste was prevented from
being supplied to the substrate. After all wiring patterns were
formed, the substrate was baked at 400.degree. C. to fix and fit
the wiring patterns.
[0168] The wiring pattern thus formed in this embodiment was used
as a heater (soaking plate=AlNx, heater material=silver) by
supplying power thereto, the plate-form substrate was heated to
150.degree. C. As a result, the uniformity in temperature was
.+-.0.2.degree. C. The wiring pattern formed by a conventionally
used printing using silk screen (coating spots were present in the
printing direction) was used as a heater by supplying power
thereto. The difference in temperature was within .+-.1.degree. C.
since resistance greatly differed. Compared to the conventional
case, in this embodiment, uniformity in temperature was
dramatically improved as described. Furthermore, the wiring pattern
formed by using a conventional liquid supply nozzle in which output
is controlled within the nozzle, was used as a heater by supplying
power thereto. As a result, difference in temperature was
.+-.0.6.degree. C. since the resistance value differed by the
influence of a pulsation flow. Hence, compared to this case, the
uniformity in temperature was drastically improved in this
embodiment.
[0169] Fifth Embodiment
[0170] This embodiment relates to an apparatus having a liquid
supply nozzle and a liquid shut-out portion which are integrated as
a one body. We will explain how to overcome problems produced when
the nozzle moving speed is high in the case where a liquid to be
supplied from a nozzle vertically to a substrate is shut out by the
shut-out portion while the integrated body is moved along the
substrate.
[0171] In the integrated body, when the nozzle moves faster than
the movement of the liquid shut-out portion, a problematic
phenomenon may sometimes come up in which no liquid is supplied
even if the nozzle reaches outside the non film formation region,
in other words, even if the nozzle reaches the film formation
region. The film formation state of this case is shown in FIG.
23.
[0172] FIG. 24A shows a cross-sectional view showing a structure of
a liquid film formation apparatus according to the fifth embodiment
of the present invention. Furthermore, FIGS. 24A-24C show cross
sectional views showing selective film formation steps of a liquid
film 14 using the aforementioned liquid film formation
apparatus.
[0173] The liquid film formation apparatus has a liquid supply
nozzle 95 and a liquid shut-out portion 96. The liquid supply
nozzle 95 outputs a liquid 13 to a substrate 15. The liquid
shut-out portion 96 shuts out the liquid 13 output from the liquid
supply nozzle 95 from being supplied to the substrate 15. The
liquid supply nozzle 95 and the liquid shut out portion 96 are
constructed independently movable. Furthermore, the liquid shut-out
portion 96 is arranged at a level (height) between a nozzle port of
the liquid supply nozzle 95 and the substrate 15.
[0174] In the liquid film formation apparatus thus constructed, a
liquid is coated as follows.
[0175] As shown in FIG. 24A, a substrate 15 having an alignment
mark on the surface is horizontally placed on a holder (not shown).
The liquid supply nozzle 95 for supplying a liquid dropwise to the
substrate 15 is arranged right above the substrate. The liquid
supply nozzle 95 is equipped with a nozzle moving portion 97.
[0176] When the liquid 13 is supplied to the substrate 15, the
nozzle 95 is moved by the nozzle moving portion 97, and
simultaneously the liquid 13 is supplied from the nozzle 95 to a
film formation region on the substrate 15. In this case, before the
liquid supply nozzle 95 is moved, the liquid shut-out portion 96 is
moved and arranged right above the alignment mark 42 (non film
formation region).
[0177] Then, as shown in FIG. 24B, the liquid supply nozzle 95
moves while the liquid 13 is output, and reaches right above the
alignment mark 42 (non film formation region). Then, the liquid
shut-out portion 96 shuts out the liquid 13 output from the nozzle
95 from being supplied dropwise to the substrate 15. In this way,
the supply of the liquid 13 to the substrate 15 is shut out.
Furthermore, when the liquid supply nozzle 95 passes over a
position right above the alignment mark 42, the shut-out of the
liquid 13 by the liquid shut-out portion 96 is released as shown in
FIG. 24C. In this manner, the supply of the liquid 13 onto the
substrate 15 is initiated.
[0178] FIG. 25 is a top view of a state of a liquid film formed in
this embodiment. As shown in FIG. 25, a liquid film 14 is securely
formed in the film formation region outside the non film formation
region having the alignment mark 42 formed thereon. Hence, the
problem of no liquid (13) supply to the film formation region can
be overcome.
[0179] In a conventionally-used apparatus having the liquid supply
nozzle and the liquid shut-out portion integrated as one body, when
a moving speed of the nozzle is faster than the movement of the
shut-out mechanism of the liquid shut out portion, a problematic
phenomenon comes up in which a liquid is not supplied to the region
except the non film formation region. In this embodiment, the
liquid shut-out portion is previously moved to the non film
formation region and the shut-out mechanism is operated before the
liquid supply nozzle passes over there. Then, the liquid supply
nozzle is operated so as to move across the liquid shut-out
portion. In this way, the non film formation region can be formed
only in a desired region. As the liquid shut-out portion, a
physical method of shutting out a liquid may be employed. That is,
the liquid may be shut-out by either sucking or gas release.
[0180] Note that the present invention is not limited to the
aforementioned embodiments and may be modified in various ways
within the gist of the present invention.
[0181] As explained in the foregoing, according to first to fifth
embodiments, it is possible to prevent generation of particles by
maintaining an amount of the liquid output from the nozzle at a
constant level and shutting out the liquid supply to the substrate
by the liquid shut-out portion arranged below the nozzle portion.
Furthermore, it is possible to supply the liquid uniformly on the
substrate without generating a pulsation flow in the liquid
immediately before the shut-out of the liquid supply and at the
time the liquid supply is reinitiated after the shut-out of the
liquid supply.
[0182] If the first and fifth embodiments of the present invention
are used, it is possible to provide a film formation method and
apparatus capable of suppressing contamination of the liquid film
with impurities when the liquid film is selectively formed on the
substrate and simultaneously forming the liquid film with a uniform
thickness.
[0183] Sixth Embodiment
[0184] In this embodiment, we will explain a method of coating an
SOG solution on an uneven substrate to make the surface flat.
[0185] FIG. 26 is a diagram showing a schematic structure of a
coating apparatus according to the sixth embodiment of the present
invention. The coating apparatus has a liquid supply nozzle 11, a
nozzle driving section 81, and pattern design data 17. The liquid
supply nozzle 11 supplies a liquid 13 dropwise to a substrate 18.
The nozzle driving section 81 moves a liquid supply nozzle 11 on
the basis of the pattern design data 17.
[0186] With reference to FIGS. 27A-27C, we will explain steps of
forming an insulating film on the substrate 18 using the coating
apparatus. In this embodiment, SOG is employed as a material for
the insulating film. SOG is used in the form of an SOG solution by
dissolving it with thinner so as to contain 20% of a solid
matter.
[0187] As shown in FIG. 27, the substrate 18 is formed of an
unprocessed substrate 19 and a structure 23 such as wiring formed
on the substrate 19. Thus, a depressed portion 24 is present on the
substrate 19. The depth of the depressed portion (space) 24 formed
in the substrate 18 is about 0.25 .mu.m. In the substrate 18, there
are a isolate line region, a line & space region, and an
isolate space region.
[0188] To form an SOG film on the substrate 18 having the structure
as shown in FIG. 27, the substrate 18 is fixed and the SOG solution
is continuously output from a liquid supply nozzle (aperture: 50
.mu.m) 11 to the unmoved substrate 18. Then, the liquid supply
nozzle 11 is moved reciprocally in a row direction as shown in FIG.
28. Every time the liquid supply nozzle 11 reaches at a point of
return present outside the pattern formation region 31, it is moved
in the line direction at a predetermined pitch. The pitch in the
line direction is previously set at a value smaller than the width
of liquid spread in the line direction on the substrate 18.
[0189] The cross sectional view of the output portion when the
liquid 13 is output from the liquid supply nozzle 11 is shown in
FIG. 29. As shown in FIG. 29, the SOG solution 35a output from the
nozzle 11 onto the substrate 18 is spread thin. If the moving pitch
in the line direction is set at a value smaller than the spread
amount (width) of the SOG solution in the line direction, the newly
spread SOG solution 35b comes in contact with the SOG solution 36
which has been already supplied on the substrate 18. Hence, all
lines of the SOG solution output from the liquid supply nozzle 11
are in contact with each other. In this manner, the SOG solution
can be coated over the entire pattern formation region 31.
[0190] In this embodiment, film formation conditions are determined
in order to obtain an output amount attaining the SOG (SiO.sub.2)
film after baking in a thickness of 1 .mu.m, under the conditions:
nozzle moving speed V.sub.0=100 mm/sec, moving pitch P of a nozzle
at both sides during reciprocal movement=100 .mu.m.
[0191] On the basis of the film formation conditions thus
determined, the SOG solution is coated by changing a moving speed V
in the row direction of the nozzle 11 depending upon the ratio of a
depressed portion per unit area. Note that the moving speed is
varied in units of 100 .mu.m. The moving speed V is defined by
Equation (1)
V=V.sub.0/((t-d)+dS) (1)
[0192] where S is the ratio of the depressed portion in 100
.mu.m.sup.2 region, d is a depth of the depressed portion, and t is
a thickness of a film to be formed.
[0193] When a substrate had a projection/depression pattern shown
in FIG. 30, a nozzle moving speed was changed as follows: The
moving speed was set at 229 mm/sec in the region whose ratio of
depressed portion is 75%. The moving speeds for regions having
depressed portion ratios of 50% and 12% were set at 267 and 357
mm/sec. During the film formation process, the SOG solution output
from the liquid supply nozzle 11 spread with the passage of time
and finally formed a film having a width of about 100 .mu.m.
[0194] As a result, a flat surface of the SOG liquid film was
obtained on the substrate 18 after coating of the SOG solution was
completed in accordance with such a coating method. Furthermore,
the surface level of the SOG liquid film, that is, the height of
the SOG solution from the substrate 19 (not from a pattern such as
wiring), was not varied depending upon the regions. Thereafter, the
substrate 18 was shaken (moved reciprocally) in a horizontal
direction by about 2 mm during vaporizing the solvent to further
move the SOG solution. In this manner, the SOG solution is further
flattened.
[0195] Furthermore, as shown in FIG. 27B, an SiO.sub.2 film 25 was
formed by vaporizing the solvent slowly. The film thickness of the
SiO.sub.2 film 25 formed on the pattern (projecting portion) was
0.25 .mu.m. The film thickness of the SiO.sub.2 film 25 formed in
the depressed portion was 0.50 .mu.m. The difference between the
projecting portion and the depressed portion of the surface of the
SiO.sub.2 film was about 3 nm. It is therefore demonstrate that the
SiO.sub.2 film 25 having a flat surface was successfully formed on
the substrate 18.
[0196] As shown in FIG. 27C, an antireflection film 26 having an
antireflection effect against a DUV light (wavelength: 248 nm) was
formed on the SiO.sub.2 film 25 in a thickness of 50 nm by using
the same apparatus as used in the SOG film formation. In this case,
the antireflection film 26 had to be formed in a uniform thickness
on the surface of the almost flat SiO.sub.2 film 25 along with the
projections and projections of the surface. The film was formed by
maintaining a moving speed of the liquid supply nozzle 11 constant,
controlling the ratio of a solid matter to the solvent for the
antireflection film 26, and controlling the moving pitch of the
nozzle to a value less than the extent of the liquid (13) spread.
When the antireflection film 26 was formed, the nozzle moving speed
V is controlled so as to be faster by 1% at the depressed portion
and slower by 1% at the projecting portion. The control was made on
the presumption that the film thickness of the depressed portion
may be increased by free-flow movement of the solution after the
liquid film formation. To the projecting portion, a larger amount
of the solution was given in advance by the amount corresponding to
a loss in film thickness, which presumably lose by the free-flow
movement during the film formation process.
[0197] Subsequently, using the same method as in the case of the
antireflection film 26, a resist film was formed on the
antireflection film 26 in a thickness of 0.25 .mu.m. The solid
matter for the antireflection film 26 was set at 1% (viscosity: 1.5
cp) and the solid matter for the resist film was 3% (viscosity: 1.7
cp). Thereafter, DUV light exposure, PEB(post exposure bake),
development were performed to obtain a resist pattern 27 having a
wiring width of 0.25 .mu.m. As described, the substrate surface was
flattened with high accuracy. Thereafter, the antireflection film
and the resist film were formed on the substrate depending upon
minor projections and depressions. It is therefore possible to form
a pattern having a wiring width controlled within 3 nm in a quite
satisfactory state.
[0198] In the aforementioned embodiment, as shown in FIG. 31A, the
SOG solution was coated while the nozzle was moved from one side to
the other side of the periphery of the substrate 18. However,
depending upon the conditions of the SOG solution and the state of
the substrate surface, the following defects may be sometimes
produced if this coating method is used.
[0199] FIG. 31B is a cross-sectional view of the substrate shown in
FIG. 31A having the defects. In the beginning region 28 where the
liquid supply nozzle 11 moving on the substrate 18 terminates
output of the liquid, a solvent concentration is decreased and
furthermore the solvent is vaporized from the beginning region 28,
with the result that aggregation takes place in the SOG solution.
As a result that the SOG solution are solidified, the beginning
region 28 of a film 40 is raised in an angular form (as shown in
FIG. 31B) and the thickness of the film around the beginning region
28 is reduced.
[0200] When such a defect takes place, the SOG solution is coated
while the nozzle 11 is moved both edges of the outer peripheral
portion of the substrate (terminal point 38) from inward (initial
points 37). To describe more specifically, the nozzle 11 is moved
reciprocally in a line direction from one edge of the inner portion
of the substrate 18. When the nozzle 11 reaches a point of return,
it is moved in the row direction by a predetermined pitch and the
coating of the SOG solution is continued until it reaches the outer
peripheral portion of the substrate 18. In addition, the nozzle 11
is moved reciprocally in a line direction from the other edge of
the inner portion of the substrate 18. When the nozzle reaches a
point of return, it is moved in the row direction by a
predetermined pitch and the coating of the SOG solution is
continued until it reaches the outer peripheral portion of the
substrate 18. In this case, care must be taken to avoid overlapping
of coating. In this case, the aforementioned predetermined pitch is
set at a value less than the extent of the liquid spread in the row
direction of the substrate 18. If the coating is performed in this
manner, the concentration of the solvent is not decreased in the
outer peripheral portion (terminal point of the output) of the
substrate. As a result, no aggregation occurs and the beginning
region 28 of the film 40 is not raised in an angular form as shown
in FIG. 32B.
[0201] If attention is directed to the outer peripheral portion 39
of the substrate 18, the liquid is coated so as to obtain the film
40 having a smooth curved line of the outer peripheral portion, the
surface tension is applied to the outer peripheral portion 39 of
the substrate 18 inwardly in the same direction. As a result,
aggregation takes place in the film of the outer peripheral
portion, with the result that the obtained film is thick. Then, if
the liquid is coated so as to obtain the film 40 having a zigzag
outer peripheral portion (ria shoreline), as shown in FIG. 33B, the
surface tension is dispersed. Therefore, it is possible to prevent
the outer peripheral portion 39 from increasing in thickness. In
the case where the zigzag line is formed as shown in FIG. 33, it is
better to control the shut-out timing of the liquid by using the
methods shown in FIGS. 24A-24C. Note that FIGS. 33A, 33B are
magnified views of the peripheral portion of the substrate.
[0202] A diluted SOG solution is used as the liquid in the
embodiments of the present invention; however, the liquid is not
limited to this. An antireflection film, a conducting film, and a
resist film to be used in a lithographic process, can be formed in
the same manner. When these films are formed, it is desirable to
dilute raw materials with thinner. When diluted, a solid material
is desirably contained in a percentage of 3 or less. Furthermore,
the present invention is applicable to the case where a film is
formed by using a metal paste as a wiring material. In the
embodiments of the present invention, the diluted solution using
thinner is used as the liquid. However, a molten solution of a raw
film material may be used.
[0203] In the case where the ratio of the depressed portion does
not change in the moving direction (row direction) of the nozzle
but changes in the perpendicular direction to the moving direction
(line direction), a film having a flat surface can be formed by
changing a moving pitch while maintaining the moving speed. When
needed, both the moving speed and moving pitch of the nozzle may be
changed.
[0204] In the embodiments, the ratio of the depressed portion on
the substrate 18 is obtained on the basis of the pattern data at
the time the designing. As shown in FIG. 34, an image of the
surface of the substrate 18 is taken by image taking sections 43a,
43b. The ratio of the depressed portion can be obtained through
arithmetic calculation by an arithmetic image processing portion
44. The image taking section 43a (43b) consists of a CCD or the
like and positioned in the front of the moving direction of the
liquid supply nozzle 11. Alternatively, the ratio of the depressed
portion may be obtained from the image itself. Furthermore, when a
micro pattern of a measurable wavelength or less is present, the
pattern may be obtained in the form of contrast (light and shade)
of the reflection light. The contrast value may be used as the
ratio of the depressed portion. In consideration of the reciprocal
movement of the liquid supply nozzle 11, it is preferred to set the
image taking sections 43a, 43b both in forward and backward moving
directions.
[0205] Seventh Embodiment
[0206] In this embodiment, a plurality of liquid supply nozzles
(aperture: 50 .mu.m) are arranged in the direction perpendicular to
the nozzle moving direction. The SOG solution is coated by the
liquid supply nozzles the output amount of which can be
independently controlled Note that the same substrate and SOG
solution as those of the sixth embodiment are used.
[0207] An output amount G0 of the SOG solution was obtained so as
to attain a film thickness of 1 .mu.m after the SOG (SiO.sub.2)
film was baked under the conditions: nozzle moving speed
V.sub.0=100 mm/sec, moving pitch P at a point of return=100 .mu.m.
As a result, the output amount G0 was 5 .mu.l/sec.
[0208] On the basis of the film formation conditions determined, a
film was formed by changing the output amount G depending upon the
ratio of the depressed portion per unit area. The output amount G
was controlled in units of 10 .mu.l. The output amount G was
defined by Equation (2)
G=G0 ((t-d)+dS) (2)
[0209] where S is the ratio of the depressed portion in a region of
100 .mu.m.sup.2, d is a depth of the depressed portion, and t is a
thickness of a film to be formed.
[0210] The coating apparatus of the embodiment has liquid supply
nozzles 52a-52g linearly arranged in the direction perpendicular to
the moving direction (in a line direction if the moving direction
is a row direction) as shown in FIG. 35. A liquid deliver pump (not
shown) is connected to the upstream side of each of the liquid
supply nozzles 52a-52g. The output amount from each of the liquid
supply nozzles 52a-52g can be controlled by changing a deliver
amount of each of the liquid deliver pumps.
[0211] The SOG film was formed by supplying the SOG solution from
the liquid supply nozzles 52a-52g in different amounts depending
upon the ratio of the depressed portion on the substrate 18.
Regions 53, 54, 55 indicate the areas whose ratios of the depressed
portion are small, medium and large. The deliver amount of the
liquid deliver pump can be modified in accordance with Equation (2)
depending upon the ratio of the depressed portion arithmetically
obtained on the basis of the pattern design data of the substrate
18.
[0212] For example, when a film was formed on the depressed pattern
(shown in FIG. 36), the output amount was controlled as follows. In
the case where the ratio of the depressed portion was 75%, the
output amount was set at 2.19 .mu.l/sec. If the ratios were 50% and
12%, the output amounts were set at 1.87 .mu.l/sec and 1.40
.mu.l/sec. In FIG. 36, the regions 64a-64g correspond to the
regions whose surfaces are coated with the SOG solutions supplied
from the liquid supply nozzles 52a-52g, respectively.
[0213] The SOG solutions output from the liquid supply nozzles
52a-52g spread with the passage of time and finally formed a film
of about 100 .mu.m in width. After completion of coating with the
SOG solution, the surface of the SOG liquid film formed on the
substrate 18 was flat. The surface level of the SOG liquid film,
that is the height from the surface of the substrate (not from the
pattern such as wiring), did not change depending upon the regions.
Thereafter, the substrate 18 was further moved horizontally back
and forth by about 2 mm to allow the SOG solution to move free
during next vaporizing process.
[0214] The solvent is allowed to slowly vaporize to form a
SiO.sub.2 film 56 as shown in FIG. 37. As a result, the surface of
the substrate was further flattened. The film thickness of the
SiO.sub.2 film 56 formed on the pattern was 0.25 .mu.m. The film
thickness of the SiO.sub.2 film 56 formed on the depressed portion
was 0.50 .mu.m. The difference between the projecting portion and
the depressed portion on the was about 5 nm. Therefore, it is
demonstrated that the SiO.sub.2 film 25 having a flat surface was
formed on the substrate 18.
[0215] Furthermore, in the same manner as in the sixth embodiment,
an antireflection film having an antireflection effect against DUV
light (wavelength: 248 nm) was formed on the SiO.sub.2 film in a
film thickness of 50 nm. Since the antireflection film is necessary
to form uniformly on the slightly uneven substrate 18, the output
amount of the liquid to the depressed portion was set at an amount
lower by 1% than the standard amount. The output amount of the
liquid to the projecting portion was set at an amount higher by 1%
than the standard amount. This is made on the presumption that the
film thickness of the depressed portion may be increased by
free-flow movement of the solution after film formation process. To
the projecting portion, a larger amount of the solution was given
in advance by the amount corresponding to a loss in film thickness,
which presumably lose by the free-flow movement during the film
formation process.
[0216] Subsequently, using the same manner as in the case of the
antireflection film formation, a resist film was formed on the
antireflection film in a film thickness of 0.25 .mu.m. The solid
matter for the antireflection film was set at 1% (viscosity 1.5
cp). The solid matter for the resist film was 3% (viscosity: 1.7
cp). Furthermore, light exposure, PEB, and development are
performed to form a resist pattern having a wiring width of 0.25
.mu.m. As described, the surface of the substrate was flattened
with high accuracy. The antireflection film and the resist film
were formed depending upon the projections and depressions. As a
result, the pattern whose wiring width was controlled within 3 nm
was successfully obtained.
[0217] Note that the present invention is not limited to the
aforementioned embodiments. In the aforementioned embodiments, the
diluted SOG solution is used as the liquid; however, the liquid is
not limited to this. An antireflection film, a conducting film and
a resist film to be used in lithographic process, can be formed in
the same manner. To form these films, raw materials were diluted
with thinner. The solid matter contained therein is desirably 3% or
less. Furthermore, the present invention is applicable to the film
formation using a metal paste as a wiring material.
[0218] A plurality of liquid supply nozzles used in the embodiments
may be arranged at appropriate intervals or at the same intervals
as those of chips. In this case, since the liquid is supplied so as
to fill the same difference between the projecting portion and the
depressed portion as that of chips, the output amounts of the
liquid supply nozzles can be integrally controlled, with the result
that operational convenience can be dramatically increased.
[0219] In the aforementioned embodiments, the liquid supply nozzle
is moved. However, the substrate may be moved, while the position
of the liquid supply nozzle is fixed. Alternatively, both the
liquid supply nozzle and the substrate may be moved. The movement
direction is not limited to those shown in the embodiments. They
may be moved in such a way that the liquid output from the nozzle
draws a spiral.
[0220] The extend of liquid spread can be controlled by controlling
the solid matter contained in the liquid, the viscosity or output
speed of the liquid, and a moving speed of the substrate or the
liquid supply nozzle.
[0221] The present invention can be carried out by modifying it in
various ways within the gist thereof.
[0222] As explained in the foregoing, according to the sixth and
seventh embodiments, a liquid is efficiently coated on a processing
surface of a substrate by relatively moving the substrate and a
spray nozzle while the liquid is continuously output to the
substrate. Furthermore, it is possible to form a coating film the
entire surface of which is flat by changing the moving speed, the
moving pitch of the nozzle, or the output amount of the liquid
depending upon the ratio of the depressed portion of the
substrate.
[0223] If the sixth and seventh embodiments are used, it is
possible to provide a film formation method of coating a liquid
film on the substrate efficiently in a uniform thickness (thickness
from the substrate surface but not from the pattern) without any
influence from the uneven pattern formed on the substrate.
[0224] 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.
* * * * *