JP2000157906A - Sheet coating method and sheet coating device and production of color filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease the build-up part in film thickness at the time of starting and stopping coating to enlarge the effective region in a coating process using a die coater. SOLUTION: The build-up part in film thickness formed at the time of starting and stopping coating is decreased by using a solvent for a coating material or a coating material diluted in the concentration of solid portion as a diluted liquid, forming a slit 7 for the diluted liquid in addition to a slit 6 for the coating material in a mouth piece 12 of a coating material discharge device and discharging the diluted liquid from the slit 7 at the time of starting and stopping the coating to mix the coating material discharged from the slit 6 with the diluted liquid to apply the coating material diluted in the concentration of solid portion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method of supplying a liquid paint in a single-wafer system in precision coating such as resist coating in a semiconductor manufacturing field and ultraviolet absorbing layer coating in an optical filter manufacturing field. The present invention relates to a sheet-fed coating method for coating a surface of a material to be coated using a die coater, a sheet-fed coating apparatus for performing the method, and a method for manufacturing a color filter using the method.

[0002]

2. Description of the Related Art Conventionally, a small substrate such as a plastic substrate for an optical filter, a glass substrate for a liquid crystal display, and a glass substrate for a color filter, having a length of less than 1 m in a coating direction. It is strongly demanded that various paints be applied thinly and uniformly.
In order to form a coating film on such a substrate industrially, a single-wafer coating method is used in which the material to be coated is supplied one by one to a coater, the coating material is applied, and the coating material is conveyed to the next process such as drying. Will do.

[0003] In forming a coating film on a material to be coated, a spin coater, a bar coater, and a roll coater are widely used.

[0004] Among them, a method using a spin coater is as follows.
This method is widely used for applying a photoresist to a semiconductor wafer, and a coating film can be formed by dropping a coating material on the center of the surface of a rotating workpiece. By setting the kind of coating material suitable for this method to the coating film obtained by this method, the film thickness can be fairly accurately uniformed over the entire range of the material to be coated. However, the amount of paint used to obtain a coating film having a predetermined thickness is extremely large, which is uneconomical. In addition, paint may adhere to the edge or back surface of the material to be coated, or the paint scattered in the apparatus may gel or solidify, and the process lacks stability and cleanliness. It causes quality deterioration.

A method using a roll coater is a method of transferring a coating material to a material to be coated via a roller, and is used for coating a long material to be coated or a material wound on a roll. Can be performed. However, because the paint is sequentially sent from the pan to the application roll and the material to be coated, the paint is exposed to the air for a long time, and as a result, the moisture absorption of the paint,
Not only is it easy to deteriorate due to oxidation, but also foreign substances are likely to be mixed. As a result, the quality of the coated product is reduced.

The method using a bar coater is a method in which a coating material is applied to a material to be coated using a bar in which a thin wire is wound around a rod. In this method, the wire wound on the rod comes into contact with the material to be coated.

In consideration of such inconvenience, a die coating method using a die coater has been recently proposed. Proposals for applying a die coater to the production of a color filter have been proposed in Japanese Patent Application Laid-Open Nos.
42407 and JP-A-6-339656.

[0008] Die coaters have been widely used for thick film coating and continuous application of high-viscosity paints, and US Pat. 230,793, U.S. Pat. No. 4,696,8
No. 85, U.S. Pat. No. 2,761,791, coating methods such as a curtain flow method, an extrusion method and a bead method are known. Above all, in the above-mentioned bead method, paint is discharged from a slit provided in a die coater die, and a paint pool called a paint bead is formed between the die and a work material that relatively moves while maintaining a certain interval. Then, in this state, the paint is drawn out as the material to be coated travels to form a coating film.
If the bead method is used to continuously form a coating film by supplying the same amount of paint from the slit as the amount consumed by coating film formation, the formed coating film will have considerable film thickness uniformity. High accuracy can be achieved. In addition, there is almost no waste of paint, and since the paint feed path is sealed until it is discharged from the slit, it is possible to prevent the deterioration of paint and the intrusion of foreign matter, and maintain the quality of the obtained coating film high. it can.

[0009]

However, in the production of a color filter for a liquid crystal display, when coating a colored layer, the unevenness of the film thickness directly affects the quality as unevenness of the color. The thickness unevenness affects the gap of the liquid crystal layer. For this reason, application of a thin film having high film thickness uniformity is required.

Although the area where the film thickness uniformity is within a certain value can be used as the effective area, the die coating method is a discontinuous single-wafer coating method. , A raised portion having an uneven thickness is formed. For this reason, in the die coating method, the effective area tends to be smaller due to the swelling portion as compared with the spin coating method which is a conventional technique.

Further, since the maximum height of the raised portion is 1.5 times or more the average film thickness of the coated surface, the process after the coating process, for example, the development after the photoresist coating is performed. In some cases, problems may occur.

As a method of eliminating the swelling portion, generally, a relative speed between a material to be coated and a paint discharge device, a paint discharge rate (a discharge amount per unit time), and a tip of a die of the paint discharge device. Methods such as controlling the distance (clearance) between the substrates have been adopted. Further, Japanese Unexamined Patent Publication No.
As disclosed in Japanese Patent No. 229497, there is a proposal to solve this problem by controlling the shape of a paint bead. However, when the film thickness is controlled by controlling the relative speed and the discharge rate from the start of coating to the steady coating state or from the steady coating state to the end of coating, the thickness changes instantaneously. It is difficult to completely control the behavior of the paint bead,
When the thickness is adjusted by a method of reducing the film thickness, this may cause breakage of the paint bead and may lead to a lack of stability in the coating process. Also, from the viewpoint of the stability of the coating process, it is desirable to increase the volume of the paint bead to some extent.

An object of the present invention is to solve the above-mentioned problem and realize a single-wafer coating method for forming a coating film having a uniform thickness and a wide effective area with good yield on a material to be coated in coating by a die coater. Another object of the present invention is to provide an apparatus for performing the method, and to provide a method for manufacturing a color filter using the coating method.

[0014]

According to a first aspect of the present invention, there is provided a coating material discharge device on a surface of a coating material while at least one of the material to be coated and the coating material discharging device is relatively moved with respect to the other. A single-wafer coating method in which a paint is discharged from a slit to form a coating film, wherein the paint and a diluent of the paint are mixed in the paint discharge device or at the time of discharge from the device, whereby the paint is coated. The coating film is formed while changing the solid content concentration.

Further, the invention of claim 2 provides two paint supply devices for paint and diluent, and discharges the paint and diluent supplied from the paint supply device respectively to the workpiece. A paint discharge device having a slit, a stage for holding the material to be coated, and a means for moving at least one of the paint discharge device and the stage relative to the other. It is a sheet-fed coating device.

Further, according to the third aspect of the present invention, after the two paint supply devices for the paint and the diluent are mixed, and the paint and the diluent supplied from the paint supply device are mixed, the mixture is directed toward the material to be coated. A paint discharge device having a slit for discharging, a stage for holding the workpiece, and a means for moving at least one of the paint discharge device and the stage relative to the other. It is a sheet-fed coating device.

Further, the invention according to claim 4 is a method of manufacturing a color filter having a light-shielding layer having an opening, a colored layer filling at least the opening, and a protective layer on a transparent substrate. 2. A method for producing a color filter, comprising using the sheet-by-sheet coating method according to claim 1 in a step of forming at least one layer of a light-shielding layer, a colored layer, a protective layer, and a resist used in the steps of producing these layers. Is the way.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors pay attention to the solid content concentration of a coating material in a coating process using a die coater, and sequentially control the solid content concentration so that a coating film at the start of coating and at the end of coating can be obtained. It has been found that the film thickness can be controlled, and the present invention has been achieved.

At the start of coating by the die coating method, it is necessary to form a coating bead at the tip of the die of the coating apparatus in a straight line without a break in the coating width direction. For this reason, at the start of coating, the thickness of the coating film becomes thicker than in the regular coating section. Also, at the end of coating, the base is moved away from the material to be coated, so that a part of the paint bead remains on the material to be coated as it is, and the coating film in this part is larger than the film thickness of the regular coating part. It gets thicker.

On the other hand, from the viewpoint of the stability of the coating process, it is desirable to suppress the tendency of the coating film to increase at the start of coating and at the end of special coating without changing the amount of coating material to be applied. desirable. For that purpose, the solid content concentration of the paint may be set lower than that in the steady application part. That is, by supplying a paint and a diluting liquid for diluting the paint to the paint ejection device and mixing them at the time of ejection, a paint having a low solid content concentration is ejected at the start of coating and at the end of coating. In addition, the film thickness can be reduced.

As described above, by controlling the solid content concentration of the coating material, it is possible to more easily and effectively control the thickness of the coating film at the start of coating and at the end of coating, as compared with the conventional method. The height of the portion can be reduced, and the uniform film thickness region can be further expanded.

FIG. 2 is a schematic diagram showing the entire configuration of an embodiment of the sheet-fed coating apparatus according to the present invention. FIG. 1 is an enlarged view around the base. 1 and 2, the paint supply device is represented by a base 12. The paint supply device according to the present invention means a system from the paint tank 25 to the metering pump 21 and the diluent tank 35 to the metering pump 31 in FIG.

The base 12 composed of the front lip 1 and the rear lip 2 is provided with a manifold 11 for making the pressure distribution of the paint uniform while flowing from the paint supply port (not shown) to the slit 6. The paint is supplied from the paint tank 25 to the base 12 by the metering pump 21. This metering pump 21 includes a gear pump, a diaphragm pump,
1 shows a positive displacement pump such as a syringe pump. Further, as another paint supply mechanism of the pump, a paint tank 25 is provided.
Is put in a pressure vessel, and pressurized air is supplied to the pressure vessel by a pressure pump to extrude the paint. Dispensing pump 21 from paint tank 25
A filter 22 and an on-off valve 23 are provided in the path of the pipe 24 up to the necessity.

On the other hand, the base 12 is provided with a slit 7 through the partition plate 3, and a diluting liquid for diluting the paint is supplied to and discharged from the slit 7. In the present invention, as the diluent, for example, a paint having a reduced solvent component and solid content concentration is used. The diluent is supplied to the base 12 from the diluent tank 35 via the pipe 34 by the metering pump 31 in the same manner as the paint. In some cases, a manifold is also provided in the supply path of the diluent to the slit 7, but in some cases, an inlet is provided directly on the slit wall surface. In FIG. 1, the diluting liquid is supplied to the slit 7 without the manifold. With this structure, it is possible to adjust the solid content concentration of the paint applied to the workpiece 9 by mixing the paint and the diluent at the tip of the base 12.

In the present invention, the base 12 is
The configuration shown in FIG. In the case of this die, the paint is supplied through the manifold 11, and a diluent supply path 41 is provided in the middle of the side wall of the slit 42. The diluent supplied from the diluent supply path 41 is mixed with the paint in the slit 42, and the paint having a reduced solid content is discharged from the slit 42.

In the step of applying a coating material to a material to be coated using the sheet-fed coating apparatus of the present invention, as shown in FIG. 2, the base 12 is coated with a predetermined gap (clearance). It is installed facing the material 9. This clearance is 20-50
0 μm is preferred. The slit gap of the die 12 (the width of the slit 6 in FIG. 1 and the slit 42 in FIG. 3 in the coating direction) is preferably 10 to 200 μm. The material 9 to be coated is placed on a flat transfer stage 13 and is vacuum-adsorbed so as not to shift during coating.

While the base 12 or the transfer stage 13 is moved in parallel, the supply of the diluent to the base 12 from the metering pump 31 is started. The relative movement distance between the base 12 and the transfer stage 13 after starting the supply of the diluting liquid is 0 to 5 mm.
Then, the supply of the paint from the metering pump 21 is started. It is more preferable that the acceleration of the metering pump at the start of the supply of the paint (the amount of increase in the discharge rate per unit time) is appropriately adjusted according to the type of the paint, the application speed, the discharge rate of the diluent, and the like. Further, the relative moving distance between the base 12 and the transfer stage 13 after starting the supply of the paint is 0 to 5 mm.
When it becomes, the supply of the diluent is stopped, and the regular coating is started. At the time of regular application, application is performed only with paint. When reaching 0.1 to 5 mm before the end of coating, supply of the coating is stopped. Similarly, when it reaches 0.1 to 5 mm before the end of coating, supply of the diluent from the metering pump 31 is started. The stop of the supply of the paint and the start of the supply of the diluting liquid depend on the type of the coating liquid, the desired film thickness, the coating speed, and the like. After reaching the coating end, the movement of the die 12 or the transfer stage 13 is stopped. By adjusting the substantial solid content concentration of the paint at the start of coating and at the end of coating in this way, a thin film having a uniform film thickness distribution is applied.

The coating method using the single-wafer coating apparatus of the present invention is preferably applied to a process of manufacturing a color filter which is a component of a liquid crystal element for color display. Usually, a color filter is formed by forming a black metal or black resin light-shielding layer called a black matrix or a black stripe on a transparent substrate, and forming an opening of the light-shielding layer as a colored pixel.
A colored layer having colored pixels of three primary colors (red), G (green), and B (blue) and a protective layer provided as needed are formed. Therefore, the coating method of the present invention using the single-wafer coating apparatus of the present invention is used for coating the resist used for forming the light-shielding layer, the coloring layer, and the protective layer or for patterning the coating film. Thereby, a coating film having a wide effective area and a uniform film thickness can be formed, and a good color filter can be formed with good yield.

[0029]

(Example 1) An acrylic photosensitive resin composition having the following composition was used as a coating material, and coating was performed using a coating device equipped with a coating material discharging device having a die having the configuration shown in FIG. Was. Photosensitive resin composition Terpolymer having the following composition 10.0 parts by weight Methyl methacrylate 5.0 parts by weight Hydroxymethyl methacrylate 3.0 parts by weight N-methylolacrylamide 2.0 parts by weight Triphenylsulfonium triflate 0.3 Parts by weight ("TPS-105" manufactured by Midori Chemical Co., Ltd.) 89.7 parts by weight of ethyl cellosolve

A 360 mm × 465 mm × 0.7 mm non-alkali glass substrate (“1737” manufactured by Corning Incorporated) was used as a material to be coated, and the slit gap was 50 μm.
The clearance was set to 75 μm, and a coating composed of the photosensitive resin composition was applied. A diaphragm pump was used as the metering pump, and a high-precision servomotor was used to drive the transfer stage.

The above-mentioned paint was charged into a paint tank, and the inside of the liquid feed path up to the die was previously filled with the paint. The diluent tank was charged with the solvent component ethyl cellosolve,
The inside of the liquid feeding path up to the die was previously filled with this solvent.
A diaphragm pump was used as a metering pump for sending the solvent.

At the start of coating, the substrate is transported at a speed of 12 mm / s, the paint is discharged at a steady rate at a rate of 32.8 μl / s, and the maximum discharge rate of the solvent is 40 μl / s. The solvent and the paint were discharged at such a discharge rate, and when the coating was completed, the coating was performed at a discharge rate as shown in FIG.

The obtained coated substrate was heated on a hot plate for 9 hours.
It was baked at 0 ° C. for 20 minutes to obtain a coating film. When the film thickness was measured in the coating direction at the center of the obtained coating film, the film thickness distribution was as shown in FIG. 6, and the average film thickness was 1.043 μm and the maximum film thickness was as shown in Table 1 below. Is 1.32 μm, and a region having a film thickness exceeding ± 5% with respect to the average film thickness is defined as a non-uniform region.
mm, the non-uniform area on the coating end side was 5 mm from the end of the substrate.

(Example 2) A coating material, a coating material, a diluting liquid (solvent) and a coating apparatus were used in the same manner as in Example 1 except that the die having the structure shown in FIG. 3 was used. And applied.

The obtained coated substrate was heated on a hot plate for 9 hours.
It was baked at 0 ° C. for 20 minutes to obtain a coating film. When the film thickness was measured in the coating direction at the center of the obtained coating film, the average film thickness was 1.064 μm, the maximum film thickness was 1.40 μm, and the average film thickness was as shown in Table 1 below. When a region having a film thickness exceeding ± 5% was regarded as a non-uniform region, the non-uniform region on the coating start side was 5 mm from the substrate end, and the non-uniform region on the coating end side was 5 mm from the substrate end. .

(Example 3) As a paint, a paint for forming a colored coating film for a color filter ("CR
-7001 "). This paint has a viscosity of 12 cP,
It is a photosensitive resin having a solid content of 24.9% by weight. As a diluent, a solvent is added to the above-mentioned paint to obtain a solid concentration of 1%.
It was used at 2.0% by weight.

In this example, the paint tank and the diluent tank were sealed in a pressure-resistant canister in the apparatus shown in FIG. 2 using the die having the structure shown in FIG. 3, and the liquid was sent by pressurizing with nitrogen. The coating capacity is the same as in Example 1, except that the clearance between the die and the material to be coated is 50 μm.
The substrate transfer speed was 20 mm / s, and the discharge rate in the steady coating portion of the paint was 28.9 μl / s. Also,
The diluent was sent under nitrogen pressure of 0.3 kgf / cm ² , and the discharge rate when the on-off valve was opened was 28 μl / s.

At the start of coating, coating was performed at the discharge rate shown in FIG. 8, and at the end of coating, coating was performed at the discharge rate shown in FIG.

The obtained coated substrate was placed on a hot plate for 9 hours.
Baking was performed at 0 ° C. for 5 minutes to obtain a coating film. When the film thickness was measured in the coating direction at the center of the obtained coating film, the film thickness distribution was as shown in FIG. 10, and the average film thickness was 1.332 μm and the maximum film thickness was as shown in Table 1 below. Is 1.73μ
m, when a region having a film thickness exceeding ± 5% with respect to the average film thickness is regarded as a non-uniform region, the non-uniform region on the coating start side is 3.5 mm from the substrate end and the non-uniform region on the coating end side. The area was 5 mm from the edge of the substrate.

Example 4 Using the glass substrate used in Example 1, patterning a three-layer chrome black matrix, and using the paint used in Example 3 for each of the three colors R, G, and B By repeating coating, baking, exposure and development, a color filter was obtained. The coating conditions were the same as in Example 3.

When a liquid crystal color display was constructed using the obtained color filters, a high-definition image could be displayed.

(Comparative Example 1) A cap having the same configuration as that of FIG. 1 except that the diluent supply slit 7 and the partition plate 3 were not provided was used, and the diluent supply system (diluent tank 3
5, coating was carried out in the same manner as in Example 1 except that an apparatus having a configuration provided with a pipe 34, an on-off valve 33, a filter 32, and a metering pump 31) was used. The substrate transfer speed is 12 mm /
s and the paint were fixed and applied at a discharge rate of 32.8 μl / s. The obtained coated substrate was baked on a hot plate at 90 ° C. for 20 minutes to obtain a coating film. When the film thickness was measured in the coating direction at the center of the obtained coating film, the film thickness distribution was as shown in FIG. 7, and the average film thickness was 1.093 μm and the maximum film thickness was as shown in Table 1 below. Is 1.76 μm, and a region having a film thickness exceeding ± 5% with respect to the average film thickness is defined as a non-uniform region.
mm, non-uniform area on the coating end side is 10 mm from the edge of the substrate
Met.

(Comparative Example 2) Coating was performed in the same manner as in Example 3 except that the die used in Comparative Example 1 was not used and the diluent was not used. The obtained coated substrate was baked on a hot plate at 90 ° C. for 5 minutes to obtain a coating film. When the film thickness was measured in the coating direction at the center of the obtained coating film,
The film thickness distribution is as shown in FIG. 11, and as shown in Table 1 below, the average film thickness is 1.294 μm, and the maximum film thickness is 2.20.
μm, when the region having a film thickness exceeding ± 5% with respect to the average film thickness is regarded as a non-uniform region, the non-uniform region on the coating start side is 14 mm from the substrate end, and the non-uniform region on the coating end side is It was 5 mm from the edge of the substrate.

[0044]

[Table 1]

[0045]

As described above, according to the present invention,
In the coating process using a die coater, by diluting the paint with a diluent as appropriate to control the solid content concentration, without reducing the volume of the paint bead, the coating film at the start of coating and at the end of coating It is possible to form a better coating film by reducing the area of the raised portion on the film surface to enlarge the effective area and reducing the height of the raised portion. In the present invention, since the volume of the coating bead is not reduced, coating defects such as stripe unevenness do not occur, and the stability of the coating process is not impaired.

Since the coating apparatus of the present invention is merely provided with a configuration for supplying a diluting liquid to a conventional die, it is not necessary to make a significant design change from the conventional coating apparatus, and it is economical to change the apparatus. Loss is small.

Further, by incorporating the above-mentioned coating method into a color filter manufacturing process, it is possible to reduce waste of paint and provide a color filter having a wide effective area and few defects.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a configuration of an example of a preferable die used in a sheet-fed coating apparatus of the present invention.

FIG. 2 is a schematic view showing a configuration of an embodiment of a single-wafer coating apparatus according to the present invention.

FIG. 3 is a sectional view showing the configuration of another example of a preferred die used in the sheet-fed coating apparatus of the present invention.

FIG. 4 is a diagram showing a discharge rate of a paint and a diluent at the start of coating in Example 1 of the present invention.

FIG. 5 is a diagram showing a discharge rate of a paint and a diluent at the end of coating in Example 1 of the present invention.

FIG. 6 is a view showing a film thickness distribution of a coating film of Example 1 of the present invention.

FIG. 7 is a diagram showing a film thickness distribution of a coating film of Comparative Example 1 of the present invention.

FIG. 8 is a diagram showing a discharge rate of a paint and a diluting liquid at the start of coating in Example 3 of the present invention.

FIG. 9 is a diagram illustrating a discharge rate of a paint and a diluent at the end of coating according to a third embodiment of the present invention.

FIG. 10 is a view showing a film thickness distribution of a coating film of Example 3 of the present invention.

FIG. 11 is a view showing a film thickness distribution of a coating film of Comparative Example 2 of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Front lip 2 Rear lip 3 Divider 4,5 Shim 6,7 Slit 8 Coating material 9 Coating material 10 Paint bead 11 Manifold 12 Cap 13 Transport stage 21,31 Metering pump 22,32 Filter 23,33 Open / close valve 24, 34 Piping 25 Paint tank 35 Diluent tank 41 Diluent supply path 42 Slit

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Junichi Sakamoto 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Kenichi Iwata 3-30-2 Shimomaruko, Ota-ku, Tokyo Non-corporation F-term (reference) 2H025 AA00 AB13 AB16 AC01 AD01 BC14 BC15 BC32 EA04 EA10 FA04 FA14 2H048 AA09 BA43 BA45 BA48 4D075 AC14 AC94 BB95Y CA48 DA06 DB13 DC22 DC24 4F041 AA02 AA06 CA02 CA04 CA15 JA16F01

Claims (4)

[Claims] 1. A coating film is formed by discharging a coating material from a slit of a coating material discharging device on the surface of the coating material while moving at least one of a coating material and a coating material discharging device relative to the other. A single-wafer coating method, wherein a paint and a diluent of the paint are mixed in the paint discharge device or at the time of discharge from the device, thereby forming a coating film while changing the solid content concentration of the paint. A single-wafer coating method. 2. A paint discharger having two paint supply devices for a paint and a diluent, and two slits for respectively discharging the paint and the diluent supplied from the paint supply device toward a material to be coated. A sheet-fed coating apparatus comprising: an apparatus; a stage for holding the material to be coated; and means for moving at least one of the coating apparatus and the stage relative to the other. 3. A paint discharger having two paint supply devices for a paint and a diluent, and a slit for mixing the paint and the diluent supplied from the paint supply device and then discharging the mixture toward a material to be coated. A sheet-fed coating apparatus comprising: an apparatus; a stage for holding the material to be coated; and means for moving at least one of the coating apparatus and the stage relative to the other. 4. A method for manufacturing a color filter having a light-shielding layer having an opening, a colored layer filling at least the opening, and a protective layer on a transparent substrate, wherein the light-shielding layer comprises:
A method for producing a color filter, comprising using the single-wafer coating method according to claim 1 in a step of forming at least one layer of a colored layer, a protective layer, and a resist used in the steps of producing these layers.