JP3466898B2 - Coating film forming method and coating device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device (L
The present invention relates to a coating film forming method and a coating device for forming a liquid coating film with a solvent such as a resist film on the surface of a substrate such as a CD substrate.

[0002]

2. Description of the Related Art For example, in manufacturing an LCD substrate,
A circuit is formed by applying a photoresist to the LCD substrate, transferring the circuit pattern to the photoresist using a photolithography technique, and developing the photoresist.
This step includes a coating film forming step of supplying the coating liquid onto the surface of the substrate.

For example, as a method for forming a resist film,
A rectangular LCD substrate is mounted and fixed on a mounting table arranged in the processing container, the opening of the processing container is closed with a lid, and the processing container and the mounting table are rotated together, and the upper surface of the substrate is A resist solution (coating solution) consisting of a solvent and a photosensitive resin is dropped in the center part, and the resist solution is applied by being spirally diffused from the center part of the substrate to the peripheral part by the rotational force and centrifugal force of the substrate. It is known how to do it.

In this method, the substrate is rotated to diffuse the resist solution from the central part of the substrate toward the peripheral part to apply the resist solution on the substrate, and the peripheral speed whose peripheral speed is significantly higher than the central position is considerable. A certain amount of resist liquid is scattered toward the processing container. In this case, the amount of the dropped resist solution applied to the substrate surface is 10 to 20%, and the remaining 80 to 90% is scattered toward the processing container.

In particular, when a resist solution is applied to a rectangular LCD substrate, a very large amount of resist solution is wasted because the resist solution is applied to the entire surface of the substrate without being left uncoated. With the increase in diameter in recent years, the size of the substrate is increasing, and in the conventional method, the amount of the resist solution wasted is further increased. It is desired to reduce the amount.

From the viewpoint of reducing the amount of the resist solution used, as a pre-step of dropping the resist solution, a thinner (solvent) is dropped onto the center of the stationary upper surface of the substrate, and the thinner is rotated and then rotated. A method of dropping a resist solution on a substrate has been proposed (Japanese Patent Laid-Open No. 8-51061).
Issue).

In this method, before dropping the resist solution,
Since the thinner is applied to the substrate to diffuse it, when the resist solution is dropped onto the substrate, the resist solution diffuses to the entire surface of the substrate through the thinner, so that the resist solution can be applied to the entire surface of the substrate. The amount of resist solution used can be reduced.

[0008]

However, according to the method disclosed in Japanese Patent Laid-Open No. 8-51061, before the dropped resist solution is sufficiently diffused in the outer peripheral portion of the substrate,
Since the drying of the resist solution progresses rapidly and the viscosity of the resist solution increases, the thickness distribution of the applied film becomes thicker in the central part of the substrate and thicker than the peripheral part, and it is difficult to make the film thickness uniform. There is a problem that there is.

The present invention has been made in view of the above circumstances, and a coating film forming method and a coating device capable of suppressing the rise of the film thickness in the central portion of the substrate and making the coating film uniform in thickness. The purpose is to provide.

[0010]

In order to solve the above problems, the first invention is a coating film forming method for supplying a coating liquid onto the surface of a substrate housed in a processing container to form a coating film. There is a step of applying a solvent on the surface of the substrate, a step of supplying a coating liquid to the surface of the substrate to form a coating film on the surface of the substrate while rotating the substrate at a predetermined speed, and decelerating the substrate. Before stopping, the process of re-supplying the central part of the coating film on the surface of the substrate with less than half the amount of the coating liquid initially supplied , and accelerating rotation of the substrate to form the coating film A method of forming a coating film, comprising the step of adjusting the thickness.

A second aspect of the present invention is a method of forming a coating film by supplying a coating liquid onto the surface of a substrate housed in a processing container, which comprises a step of coating a solvent on the surface of the substrate. , A step of supplying a coating liquid to the surface of the substrate to form a coating film on the surface of the substrate while rotating the substrate housed in the processing container together with the processing container at a predetermined speed, and decelerating the substrate until stopping. In the meantime, a step of re-supplying the coating liquid in an amount equal to or less than half the amount of the coating liquid initially supplied to the central portion of the coating film on the surface of the substrate, and a step of accelerating and rotating the substrate to adjust the thickness of the coating film. The present invention provides a method for forming a coating film, which comprises:

A third aspect of the present invention provides a method for forming a coating film according to the first or second aspect, wherein the step of supplying the coating liquid again is performed while the substrate is being decelerated.

[0013]

A fourth invention provides the method for forming a coating film according to the second invention, wherein the step of adjusting the film thickness of the coating film is performed by closing the processing container with a lid.

A fifth aspect of the present invention is a coating apparatus for supplying a coating liquid onto a surface of a substrate housed in a processing container to form a coating film, for rotating the substrate housed in the processing container. A rotation driving means, a solvent supply nozzle for supplying a solvent to the substrate for coating, a coating liquid supply nozzle for supplying a coating liquid on the surface of the substrate to form a coating film on the substrate surface,
The solvent is supplied from the solvent supply nozzle to the substrate for coating, and then the substrate is rotated at a predetermined speed to supply the coating liquid from the coating liquid supply nozzle to the surface of the substrate to form a coating film on the substrate surface. From the coating liquid supply nozzle onto the coating film on the surface of the substrate until the substrate is decelerated and stopped ,
The supply amount of the coating liquid is less than half the amount of the coating liquid to be supplied first, and then the substrate is rotated to adjust the film thickness of the coating film, the rotation driving means, the solvent supply nozzle, and the coating liquid. And a control unit for controlling the supply nozzle.

[0016]

[0017]

[0018]

[0019]

[0020]

[0021]

[0022]

[0023]

[0024]

[0025]

According to the first invention, the second invention, and the fifth invention, after the solvent is supplied to the substrate for coating, the coating liquid is supplied to the surface of the substrate while rotating the substrate at a predetermined speed, and the substrate surface is coated. The coating film is formed on the substrate, and the coating liquid is supplied again to the central portion of the coating film on the surface of the substrate until the substrate is decelerated and stopped. It is possible to form a coating film having various thicknesses.

That is, if the coating liquid is supplied again onto the coating film once formed on the substrate until the substrate is decelerated and stopped in this way, the coating liquid is applied to the coating liquid at the time of deceleration. The force toward the center acts due to the acceleration, and when the force stops, no other force acts.Therefore, the coating liquid stays in the approximate center of the substrate, and the first part of the central part of the substrate where the drying has already progressed and the viscosity has increased. It has the effect of softening the coating liquid. As a result, it is possible to suppress the swelling of the film thickness at substantially the center of the substrate and make the film thickness uniform. In particular, as in the third aspect of the invention, a force toward the center acts during deceleration, so that the function of holding the coating liquid is high.

According to the first invention, the second invention and the fifth invention , it is necessary to diffuse the coating liquid over the entire surface of the substrate by reducing the amount of the coating liquid supplied again to half or less of the amount of the coating liquid initially supplied. While sufficiently securing the diffusion effect of a certain first coating liquid, it is possible to sufficiently suppress the swelling of the film thickness at the substantially center of the substrate by the second coating liquid.

[0029]

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a perspective view showing an LCD substrate coating / developing processing system including a coating processing unit to which the present invention is applied.

This coating / developing system has a plurality of L
A cassette station 1 on which a cassette C containing a CD substrate (hereinafter simply referred to as a substrate) G is placed, and a processing unit including a plurality of processing units for performing a series of processes including resist coating and development on the substrate G. 2 and a transport mechanism 3 for transporting the LCD substrate between the cassette C on the cassette station 1 and the processing unit 2. Then, the cassette C is carried in and out at the cassette station 1. Further, the transfer mechanism 3 includes a transfer arm 11 that can move on a transfer path 12 provided along the arrangement direction of the cassettes, and the transfer arm 11 can transfer the substrate G between the cassette C and the processing unit 2. Done. An interface unit 30 is provided at the rear end of the processing unit 2,
An exposure device (not shown) can be connected to the interface unit 30. This interface unit 30
Has a function of transferring the substrate G to and from the exposure apparatus.

The processing section 2 includes a front part 2a and a rear part 2b.
And passages 15 and 16 are provided in the center, and the processing units are arranged on both sides of these passages. A relay unit 17 is provided between them.

The front stage portion 2a is provided with a main transfer device 18 movable along the passage 15, and on one side of the passage 15, a brush cleaning unit 21, a water washing unit 22, an adhesion processing unit 23, and a cooling unit. 24
However, two resist coating units 25 are arranged on the other side. On the other hand, the rear stage portion 2b includes a main transfer device 19 movable along the passage 16, and a plurality of heat treatment units 26 and cooling treatment units 27 are provided on one side of the passage 16 and two heat treatment units 26 are provided on the other side. A development processing unit 29 is arranged. The heat treatment unit 26 has two sets of two layers stacked side by side along the passage 19, and the cooling treatment unit 27 is provided in two layers on the front stage portion 2a side. The heat treatment unit 26 performs pre-bake for stabilizing the resist, post-exposure bake after exposure, and post-bake treatment after development.

The main arm 18 transfers the substrate G between the main arm 18 and the arm 11 of the transfer mechanism 3, carries in / out the substrate G from / to each processing unit of the pre-stage section 2a, and further communicates with the relay section 17. It has a function of transferring the substrate G. Further, the main arm 19 transfers the substrate G to and from the relay unit 17, transfers the substrate G to and from each processing unit of the rear stage unit 2b, and transfers the substrate G to and from the interface unit 30. It has a function to do. By thus integrating and integrating the processing units, it is possible to save space and improve processing efficiency.

In the coating / development processing system having the above-described structure, the substrate G in the cassette C is transported to the processing section 2 and is first subjected to cleaning processing by the cleaning unit 21 and the water washing unit 22 to fix the resist. In order to increase the temperature, a hydrophobic treatment is performed in the adhesion processing unit 23, and the resist is applied in the resist applying unit 25 after being cooled in the cooling unit 24. After that, the substrate G is pre-baked by one of the heat treatment units 26, cooled by the cooling unit 27, and then transported to the exposure device via the interface unit 30 where a predetermined pattern is exposed. Then, it is carried in again through the interface unit 30 and subjected to post-exposure bake processing by one of the heat processing units 26. After that, the substrate G cooled by the cooling unit 27 is transferred to the development processing unit 29.
Is developed and a predetermined circuit pattern is formed. The developed substrate G is accommodated in a predetermined cassette on the cassette station 1 by the main arms 19 and 18 and the transport mechanism 3.

Next, a resist coating unit 25 to which the coating film forming method and coating apparatus which are the subject of the present invention are applied.
Will be described. FIG. 2 shows a resist coating unit 25, which is a coating apparatus according to an embodiment of the present invention. The spin chuck 40 holds the LCD substrate G in a horizontal state rotatably by vacuum suction, and the spin chuck 40. A rotatable cup-shaped processing container (rotating cup) 42 having a processing chamber 41 surrounding the upper and outer peripheral portions of the rotating cup 42 and an opening 42 a of the rotating cup 42.
A lid body 46 that can be closed and detachably attached to the cup 42, a robot arm 50 that moves the lid body 46 between a closed position and a standby position, and an outer peripheral side of the rotary cup 42. A hollow ring-shaped drain cup 44 arranged so as to surround it, a drive motor 51 for rotating the spin chuck 40 and the rotary cup 42, and a nozzle head 90 movably provided above the spin chuck 40. A moving mechanism 100 that holds the spray head 90 and moves it between the spray head standby position and the substrate upper position, and a controller 110 that controls the coating sequence are provided. Spout 9
0 is a solvent supply nozzle 70 for supplying a solvent (solvent) A (for example, thinner) of the coating liquid and a resist liquid B which is the coating liquid.
And a coating liquid supply nozzle 80 for supplying the liquid are closely attached to each other.

The solvent A and the resist solution B flowing through the nozzles 70 and 80 are supplied to the solvent supply path and the resist solution supply path, respectively.
A temperature adjusting mechanism 91 is provided to circulate and supply the temperature adjusting liquid D for controlling the temperature.

The spin chuck 40 is made of a heat resistant synthetic resin such as polyetheretherketone (PEEK), and is driven by a drive motor 51 which can be driven according to a preset program and whose rotation speed can be varied. It can rotate (rotate) in the horizontal direction via a rotating shaft 52 that is rotated, and can move in the vertical direction by driving an elevating cylinder 53 connected to the rotating shaft 52. In this case, the rotary shaft 52 is connected to the spline bearing 57 so as to be vertically slidable. The spline bearing 57 is fitted to the inner peripheral surface of a rotating inner cylinder 56a that is rotatably mounted on the inner peripheral surface of the fixed collar 54 via a bearing 55a. A driven pulley 58a is attached to the spline bearing 57, and a belt 59a is stretched between the driven pulley 58a and the drive pulley 51b attached to the drive shaft 51a of the drive motor 51. Therefore, the rotation shaft 52 is rotated by the drive of the drive motor 51 via the belt 59a, and the spin chuck 40 is rotated. Further, the lower side of the rotary shaft 52 is disposed in a cylinder body (not shown),
In this cylinder, the rotary shaft 52 is attached to the vacuum seal portion 6
The rotary shaft 52 is connected to the lifting cylinder 53 via 0, and the rotating shaft 52 is movable in the vertical direction by driving the lifting cylinder 53, whereby the spin chuck moves in the vertical direction.

A connecting cylinder 61 is fixed to the upper end of a rotating outer cylinder 56b mounted on the outer peripheral surface of the fixed collar 54 via a bearing 55b, and the rotary cup 42 is mounted via the connecting cylinder 61. Has been. A bearing 52 having a sealing function is interposed between the bottom portion 42b of the rotary cup 42 and the lower surface of the spin chuck 40, and the rotary cup 42 is rotatable relative to the spin chuck 40. A driven pulley 58b is attached to the rotating outer cylinder 56b.
A belt 59b is wound around the drive pulley 51b mounted on the drive motor 51. Therefore, the drive from the drive motor 51 is transmitted to the rotary cup 42 by the belt 59b, and the rotary cup 42 is rotated.

In this case, the diameter of the driven pulley 58b is formed to be the same as the diameter of the driven pulley 58a mounted on the rotating shaft 52, and the same drive motor 51 is provided with the belts 59a, 5a.
Since 9b is bridged, the rotating cup 42 and the spin chuck 40 are rotated at the same speed.

The rotary cup 42 has a side wall 42c whose diameter is reduced upward, and the surface of the side wall 42c is a tapered surface 42e. An inward flange 42d is formed on the upper end of the side wall 42c toward the inner side.
The inward flange 42d of the rotary cup 42 is provided with air supply holes 64 at appropriate intervals in the circumferential direction, and exhaust holes 65 are provided at appropriate positions in the circumferential direction on the lower side of the side wall 42c. By providing the air supply hole 64 and the exhaust hole 65 in this manner, when the rotary cup 42 rotates, the air flowing from the air supply hole 64 into the processing chamber 41 flows from the exhaust hole 65 to the outside. At times, it is possible to prevent the pressure inside the processing chamber 41 from becoming negative, and after processing, the rotation cup 4
It is possible to easily open the lid body 46 without requiring a large force when opening the lid body 46 from 2.

On the other hand, an annular passage 44a is provided inside the drain cup 44, and exhaust ports 66 are provided at appropriate locations (for example, four locations in the circumferential direction) on the outer peripheral wall thereof. 66 is connected to an exhaust device (not shown). Further, in the upper portion on the inner peripheral side of the drain cup 44,
A radial exhaust passage 67 communicating with the annular passage 44a and the exhaust port 66 is formed. As described above, the exhaust port 66 is provided on the outer peripheral portion of the drain cup 44, and the exhaust passage 67 is formed on the upper inner peripheral side portion of the drain cup 44. The mist that has flowed into the drain cup 44 through the hole 64 is prevented from rising to the upper side of the rotary cup 42, and the mist can be discharged from the exhaust port 66 to the outside.

The annular passage 44a has a drain cup 44.
The outer wall 44b standing up from the bottom of the drain cup 44 and the inner wall 44c hanging from the ceiling of the drain cup 44 define a detour path, so that exhaust can be performed uniformly. Further, drain holes 44e are provided in the bottom portion 44d located between the outer side wall 44b and the inner side wall 44c at appropriate intervals along the circumferential direction.

A taper surface 44f having a taper corresponding to the taper surface 42e of the rotary cup 42 is formed on the inner peripheral surface of the drain cup 44.
2 of the tapered surface 42e and the tapered surface 44 of the drain cup 44
A minute gap is formed with f. By forming the tapered minute gap that expands downwards in this way, a pressure difference is induced from the peripheral speed difference that occurs between the upper and lower sides of the minute gap when the rotary cup 42 rotates, and this pressure difference rotates. It is possible to promote the air flow from the upper side to the lower side of the minute gap in the outer peripheral portion of the cup 42 to prevent the exhaust mist in the drain cup 44 from scattering through the minute gap to the outside of the rotary cup 42.

Further, even if there is a mist that is directed upward through the minute gap and is scattered outside the rotary cup 42, it is discharged from the exhaust port 66 through the exhaust passage 67 and the annular passage 44a in the drain cup 44. It

Although the case where the drain cup 44 is arranged so as to surround the outer peripheral side of the rotary cup 42 has been described here, the drain cup 44 is not necessarily the rotary cup 42.
Need not be disposed on the outer peripheral side of the rotary cup 42, but may be disposed on the lower side of the rotary cup 42.

A supporting member 49 extending upward is provided at the center of the upper surface of the lid 46, and a head portion 48 having a diameter larger than that of the supporting member 49 is provided at the upper end thereof. When the lid 46 is opened and closed, the cover 46 is placed under the head 48 provided on the upper surface of the lid 46 via the support member 49.
As shown by the chain double-dashed line, the robot arm 50 is inserted, and the robot arm 50 is inserted into the locking groove provided on the head 48.
After engaging the locking pin 50a protruding from the robot arm 50, the robot arm 50 is moved up and down.

A baffle plate (not shown) formed at an intermediate position between the lid 46 and the substrate G by a perforated plate having a size larger than that of the substrate G attached to the lid 46 at the central portion. ) Can also be arranged. By arranging the baffle plate in this way, the processing chamber 41 can be more reliably operated during the coating process.
It is possible to prevent the generation of turbulent flow inside.

The solvent supply nozzle 70 is connected to a solvent tank 73 via a solvent supply tube 71 which is a solvent supply path and an opening / closing valve 72, and supplies nitrogen (N ₂ ) gas into the solvent tank 73. Thus, the solvent A in the solvent tank 73 is supplied onto the substrate G by the applied pressure. In this case, the flow rate of the solvent A is controlled by controlling the pressure of the N ₂ gas, and a predetermined amount of the solvent A is supplied for a predetermined time. The solvent supply nozzle may spray the solvent.

The resist solution supply nozzle 80 is connected to a resist solution tank 82 (coating solution supply source) for containing the resist solution B via a resist solution supply tube 81 which is a resist solution supply passage. The tube 81 includes a suck back valve 83, an air operation valve 84,
A bubble removing mechanism 85 for separating and removing bubbles in the resist liquid B, a filter 86 and a bellows pump 87 are sequentially provided. The bellows pump 87 is expandable / contractible by a drive unit, and by controlling the expansion / contraction, a predetermined amount of resist liquid B is supplied to the resist liquid supply nozzle 8.
It is possible to drop it on the surface of the substrate G through 0. The bellows pump 87 makes it possible to control the supply amount of the resist liquid B which is smaller than the conventional supply amount of the resist liquid B. This drive unit has a ball screw mechanism 88 including a screw 88a, one end of which is attached to one end of a bellows pump, and a nut 88b screwed to the screw, and the screw 88a is linearly moved by rotating the nut 88b. It is composed of a stepping motor 89.

After sucking the resist solution from the resist solution supply nozzle 80, the suck back valve 83 provided in the resist solution supply system removes the resist solution B remaining on the inner wall of the tip of the resist solution supply nozzle 80 due to surface tension. This is to return the resist liquid to the inside of the resist liquid supply nozzle 80, thereby preventing solidification of the residual resist liquid. In this case, in the resist liquid supply nozzle 80 that discharges a small amount of the resist liquid B, the resist liquid B is normally supplied by the negative pressure of the suck back valve 83.
When it is pulled back to 0, the air near the tip of the nozzle 80 is also entrained in the nozzle 80, and the residue of the resist solution B adhering to the tip of the nozzle 80 enters the nozzle 80, causing clogging of the nozzle 80. In addition, the dried resist may become particles to contaminate the substrate G and reduce the yield.

The nozzle head 90 is provided so as to be movable by a moving mechanism 100 via a support member 101. Specifically, when supplying the solvent A to the substrate G, the moving mechanism 100 moves the solvent supply nozzle 70 so that the solvent supply nozzle 70 is located at the rotation center of the substrate G, and the resist solution B is applied to the substrate. When supplying to the G, the resist solution supply nozzle 80 is moved so that the resist solution supply nozzle 80 is located at the rotation center of the substrate G, and the solvent A and the resist solution B are
When the nozzle is not supplied, the injection nozzle 90 is moved to the standby position.

The controller 110 controls the drive motor 51, the valve 72, the air operation valve 84, the stepping motor 89, and the moving mechanism 100 in accordance with the coating sequence described later to rotate the substrate G and discharge the solvent and the resist solution. Control timing and discharge rate.

Next, a method of applying the resist solution to the surface of the substrate G based on the present embodiment by using the applying apparatus having the above structure will be described. FIG. 3 is a graph showing the relationship between the coating process and the rotation speed of the substrate.

First, the lid 46 of the rotary cup 42 is opened, the substrate G is transferred onto the stationary spin chuck 40 by a transfer arm (not shown), and the substrate G is held on the spin chuck 40 by vacuum suction.

In this state, as shown in FIG.
During 1.5 seconds from 0 second to 2.5 seconds (while being indicated by the symbol M), 10 cc of a solvent A, for example, thinner is supplied to the stationary substrate G from the solvent supply nozzle 70 to apply the solvent.

After applying the solvent A in this manner, the time of 3.
The spin chuck 40 is rotationally driven for 2.0 seconds from 5 seconds to 5.5 seconds (indicated by symbol N), and the substrate G is rotated at the first rotation speed (for example, rotation speed: 1000 rpm, acceleration: The rotation cup 42 is rotated at the same speed while being rotated at 1000 rpm / s). During this rotation, the resist solution B is transferred from the resist supply nozzle 80 to the center of the substrate G.
And the resist solution B is evenly applied to the entire surface of the substrate G to form a resist film on the entire surface of the substrate G. The supply amount of the resist liquid B is such that the total amount when the resist liquid is dropped again described below is, for example, 7 cc.

Then, during a period of 0.5 seconds from 5.5 seconds to 6.0 seconds (indicated by a symbol P), the spin chuck 4 is rotated.
0 from the resist supply nozzle 80 to the center of the substrate G until the substrate G decelerates and stops.
Is added again. As a result, as will be described later, a force toward the center acts on the re-supplied resist liquid B due to the acceleration during deceleration, so that the coating liquid stays in the approximate center of the substrate and the solvent ( The thinner) has a function of softening the first resist solution B in the center of the substrate G where the drying has already progressed and the viscosity has increased, and the rise of the film thickness in the center of the substrate G can be suppressed.

Then, the spin chuck 40 is closed for a time of 7.0 seconds to 20.0 seconds (indicated by the symbol Q) with the opening 42a of the rotary cup 42 closed and covered by the lid 46.
And the rotation cup 42 at a second rotation speed (for example, rotation speed: 1400 rpm, acceleration: 1000 rpm / se).
Rotate in c) to adjust the thickness of the resist film. In this case, it is preferable to set the second rotation speed to a value higher than the first rotation speed.

After the coating process is completed, the spin chuck 4
0 and the rotation of the rotary cup 42 are stopped, the lid 46 is moved to the standby position by the robot arm 50,
The substrate G is taken out by a transfer arm (not shown), and the coating operation is completed.

Next, referring to FIG. 4, a conventional coating film forming method, that is, a method of spin-coating a resist solution without pre-coating with a solvent (spin coating A method) and pre-coating a solvent with a resist solution The spin coating method (spin coating B method) and the coating film forming method (spin coating C method) according to the present invention will be compared. FIG. 4 is a schematic diagram showing a state at the time of applying the resist solution by the spin coat A, B, and C methods.

In the spin coat A method, the resist solution B is dropped onto the rotating substrate G and the solvent A is not applied in advance. Therefore, the resist solution B is applied to the central portion of the substrate G by the rotational force and centrifugal force of the substrate G. To the peripheral portion, the resist film in the center of the substrate G does not have a swell.

In the spin coat B method, the thinner A is dropped onto the center of the substrate G, the thinner A is diffused, and then the resist solution B is dropped onto the center of the rotating substrate G. Therefore, the resist solution B at the center of the substrate G is quickly replaced with the thinner A, and the rotary cup 42 is rotated with the lid 46 opened, so that the thinner in the resist solution B at the center is volatilized, The apparent viscosity of the resist liquid B becomes high. As a result, before the step of adjusting the film thickness by shaking off the resist solution B, there is a difference in the viscosity of the resist solution B between the central portion and the peripheral portion of the substrate G, and the viscosity of the central portion becomes higher than that of the peripheral portion. This means that the resist film in the central part of G is raised more than in the peripheral part.

On the other hand, in the spin coat C method according to the present invention, the thinner A is dropped on the center of the substrate G, and after the thinner A is diffused, the resist solution B is dropped on the center of the rotating substrate G. After that, while the substrate G is being decelerated, the resist solution B is supplied again onto the resist film once formed on the substrate G. Therefore, a force toward the center acts on the re-supplied resist liquid B due to the acceleration during deceleration,
The resist solution B remains in the center of the substrate G, and acts to soften the first resist solution B in the center of the substrate G where the thinner has already volatilized and the viscosity has increased. As a result, the resist film does not rise in the central part of the substrate G, and the film thickness of the resist film can be made uniform in the step of adjusting the film thickness by shaking off the resist solution B.

In this case, the amount of the resist solution B supplied again is preferably half or less of the amount of the resist solution B initially supplied. When the amount of the resist solution B supplied again exceeds half of the amount of the resist solution B supplied first, the basic diffusion effect of the resist solution B initially supplied being diffused over the entire surface of the substrate G cannot be sufficiently exerted. Because. The resist liquid B supplied again can sufficiently suppress the swelling of the film thickness in the central portion of the substrate G even if the amount is small.

The present invention is not limited to the above embodiment, but can be variously modified. In the spin coat C method described above, the resist solution B is dropped again on the center of the substrate G while the board G is decelerating. However, even if the resist solution B is dropped again at any time of deceleration and stop. Of course, it may be dropped again after deceleration and after stopping. However,
At the time of deceleration, the force toward the center acts on the resist liquid B dropped again due to the acceleration at that time, so the resist liquid B
It is preferable to drop the resist solution B again at the time of deceleration, because the resist solution B can be kept at the center of the substrate G and the processing time can be shortened by dropping the resist solution B at the time of deceleration.

Further, in the embodiment shown in FIG.
The resist solution B is dropped again to the center of the substrate G until the substrate G decelerates and stops for 0.5 seconds (indicated by the symbol P). The time is not limited to the form time, and as shown in Example 3 described later, if the deceleration time is about 0.1 seconds, the buildup of the film thickness at the central portion can be sufficiently suppressed.

Further, in the above embodiment, the case where the LCD substrate is used as the object to be processed has been described, but the present invention is not limited to this, and the invention can be applied to the formation of a coating film on another substrate such as a semiconductor wafer.

[0069]

Example 1 FIG. 5 is a graph showing the relationship between the substrate and film thickness obtained by the conventional spin coat A method and spin coat B method and the spin coat C method according to the present invention. In Example 1, the film thickness data at each position of the substrate G was tabulated by each of the spin coat A method, the spin coat B method, and the spin coat C method. The result is shown in FIG. As shown in FIG. 5, in the spin coat B method, the film thickness in the central portion of the substrate G is thicker than that in the peripheral portion, but in the spin coat C method, the substrate G is almost the same as the spin coat A method. The bulge in the center of the is gone.

Example 2 FIG. 6 is a graph showing the relationship between the substrate and the film thickness when the discharge time of the resist solution supplied again during deceleration was changed by the spin coat C method according to the present invention. . In Example 2, the discharge time of the resist liquid B supplied again during deceleration was changed by the spin coat C method. After setting the total amount of the first and second resist liquid B to 7 cc and the total discharge time of the first and second resist liquid B to 2.1 seconds,
When the first discharge time of the resist liquid B is 1.8 seconds and the second discharge time of the resist liquid B is 0.3 seconds, the first discharge time of the resist liquid B is set to 1.9 seconds and the second resist liquid B is discharged again. Of the substrate G for 0.2 seconds, and for the initial discharge time of the resist solution B of 2.0 seconds and the subsequent discharge time of the resist solution B of 0.1 second. The film thickness data at the position was tabulated. The result is shown in Figure 6.
Shown in. As shown in FIG. 6, no significant change was observed in the film thickness when the discharge time of the resist solution B was 0.1 second, 0.2 second, and 0.3 second again.

Example 3 FIG. 7 is a graph showing the relationship between the substrate and the ejection time when the ejection time of the resist liquid supplied again during deceleration is changed by the spin coat C method according to the present invention. . In Example 3, the discharge time of the resist solution B again was 0.1 seconds,
When the time was 0.2 seconds and 0.3 seconds, the relationship between the film thickness and the ejection time was obtained. As shown in FIG. 7, it can be seen that the effect of suppressing the buildup of the film thickness at the central portion of the substrate G can be sufficiently obtained even for 0.1 second.

[0072]

As described above, according to the present invention,
Until the substrate is decelerated and stopped, the coating liquid is re-supplied to the central portion of the coating film once formed on the substrate.
The re-supplied coating liquid remains in the approximate center of the substrate, and has the function of softening the first coating liquid in the approximate center of the substrate where the drying has already progressed and the viscosity has increased. as a result,
It is possible to suppress the swelling of the film thickness at substantially the center of the substrate and make the film thickness uniform. In particular, by supplying the coating liquid again while decelerating, a force toward the center acts on the coating liquid, so that the function of holding the coating liquid is high.

Further, by setting the amount of the coating liquid to be supplied again to half or less of the amount of the coating liquid to be supplied first, it is possible to sufficiently secure the diffusion effect of the first coating liquid that needs to be diffused over the entire surface of the substrate. However, it is possible to sufficiently suppress the swelling of the film thickness at the substantially center of the substrate by the second coating liquid.

[0074]

[Brief description of drawings]

FIG. 1 is a perspective view showing a resist coating / developing system to which a coating liquid forming method and a coating apparatus, which are objects of the present invention, are applied.

FIG. 2 is a cross-sectional view showing a resist coating unit which is a coating apparatus applied for carrying out the coating liquid forming method of the present invention.

FIG. 3 is a graph showing the relationship between the coating sequence and the rotation speed of the substrate.

FIG. 4 is a schematic diagram showing a state of a coating film at the time of applying a resist solution by a conventional spin coat A method and a spin coat B method and a spin coat C method according to the present invention.

FIG. 5 is a graph showing a film thickness distribution of a coating film in a conventional spin coat A method and a spin coat B method and a spin coat C method according to the present invention.

FIG. 6 is a graph showing the film thickness distribution of the coating film when the discharge time of the resist liquid supplied again during deceleration is changed by the spin coat C method according to the present invention.

FIG. 7 is a graph showing the film thickness at the center of the coating film when the discharge time of the resist liquid supplied again during deceleration is changed by the spin coat C method according to the present invention.

[Explanation of symbols]

40 ... Spin chuck (rotation driving means) 41 ... Processing room 42 ... Rotating cup 46 ... Lid 51 ... Drive motor 70 ... Solvent supply nozzle 80: Resist liquid supply nozzle 90 ... Spout 100: Moving mechanism 110 ... Controller G: substrate

─────────────────────────────────────────────────── ─── Continuation of front page (56) Reference JP 62-190838 (JP, A) JP 1-236971 (JP, A) JP 7-320999 (JP, A) JP 10- 125581 (JP, A) JP-A-8-24621 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01L 21/027

Claims (5)

(57) [Claims] 1. A method for forming a coating film by supplying a coating liquid onto the surface of a substrate housed in a processing container to form a coating film, the method comprising: coating a solvent on the surface of the substrate; While rotating at a predetermined speed, the step of supplying the coating liquid to the surface of the substrate to form the coating film on the substrate surface, and the process of decelerating the substrate and stopping it , Half the amount of coating liquid to be supplied first
A method of forming a coating film, comprising: a step of supplying the lower coating solution again; and a step of accelerating and rotating the substrate to adjust the thickness of the coating film. 2. A coating film forming method for forming a coating film by supplying a coating liquid onto the surface of a substrate housed in a processing container, the method comprising: coating a solvent on the surface of the substrate; While rotating the substrate contained in the substrate at a predetermined speed together with the processing container, a step of supplying a coating liquid to the surface of the substrate to form a coating film on the surface of the substrate, and a step of decelerating and stopping the substrate, At the center of the coating film on the surface of the substrate, half or more of the amount of coating liquid initially supplied
A method of forming a coating film, comprising: a step of supplying the lower coating solution again; and a step of accelerating and rotating the substrate to adjust the thickness of the coating film. 3. The method for forming a coating film according to claim 1, wherein the step of supplying the coating liquid again is performed while the substrate is being decelerated. 4. The method for forming a coating film according to claim 2, wherein the step of adjusting the thickness of the coating film is performed by closing the processing container with a lid. 5. A coating device for supplying a coating liquid onto a surface of a substrate housed in a processing container to form a coating film, the rotation driving means for rotating the substrate housed in the processing container. A solvent supply nozzle for supplying a solvent to the substrate for coating, a coating liquid supply nozzle for supplying a coating liquid on the surface of the substrate to form a coating film on the substrate surface, and a solvent for supplying the solvent from the solvent supply nozzle. Supply and apply to the substrate, then, while rotating the substrate at a predetermined speed, supply the coating liquid from the coating liquid supply nozzle to the surface of the substrate to form a coating film on the substrate surface, then decelerate and stop the substrate In the meantime, on the coating film on the surface of the substrate from the coating liquid supply nozzle ,
The supply amount of the coating liquid is less than half the amount of the coating liquid to be supplied first, and then the substrate is rotated to adjust the film thickness of the coating film, the rotation driving means, the solvent supply nozzle, and the coating liquid. And a control means for controlling the supply nozzle.