JPH06148420A - Production of color filter - Google Patents

Abstract

PURPOSE:To provide the process for production of the color filter which improves the adhesion of color filter patterns onto a substrate and suppresses the blister and peel of the patterns of the previous color at the time of forming the next color. CONSTITUTION:This process for production of the color filter consists in applying a colored resin on a substrate and tentatively curing the resin by heating, then subjecting the resin to exposing and developing then to normal curing by heating, removing the residues remaining on the substrate by washing with water and further subjecting the resin to a heat treatment again in the method for forming the color filter by applying the colored resin formed by dispersing at least coloring materials into a photosensitive resin and patterning the resin by a photolithographic stage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a color filter, and more particularly to a method for manufacturing a color filter for a large area color display.

[0002]

2. Description of the Related Art Conventionally, as a color filter, a mordant layer made of a hydrophilic polymer such as gelatin, casein, glue or polyvinyl alcohol is provided on a substrate, and the mordant layer is dyed with a dye to form a colored layer. A dyeing color filter that does is known.

In such a dyeing method, many dyes can be used and it is relatively easy to meet the spectral characteristics required for a color filter, but in a dyeing bath in which the dye is dissolved in the dyeing step of the mordant layer. A wet process, in which a mordant layer is soaked, is difficult to control, and a complicated process of providing an intermediate layer for dye protection is provided for each color, resulting in a disadvantage of low yield. In addition, the heat resistance of dyeable dyes is relatively low at about 150 ° C or lower,
When the color filter requires thermal treatment,
In addition to the difficulty in specifications, the dyeing film itself has the drawback of being inferior in reliability such as heat resistance and light resistance.

On the other hand, conventionally, there is known a color filter using a coloring resin in which a certain coloring material is dispersed in a transparent resin. For example, according to a color filter characterized by using a colored resin film in which a coloring material is mixed with a photosensitive resin, a fine pattern can be formed only by a photolithography process that is common for color filter manufacturing methods, and the process can be simplified. It becomes possible.

However, in the case of forming a color filter using a coloring resin obtained by mixing a coloring material with such a photosensitive resin, generally, the coloring material itself absorbs light in the exposure wavelength range, and thus the photosensitive resin is photocured. The exposure energy required for this is much higher than usual.

In general, the light intensity of the photosensitive resin at the time of exposure decreases exponentially as it goes into the depth direction from the light irradiation surface. Therefore, the attenuation of the incident light intensity at the time of exposure from the light irradiation surface to the depth direction due to the mixing of the coloring material having the light absorbing property into the photosensitive resin becomes extremely large, and in some cases, the bottom portion of the photosensitive coloring resin film is reduced. The photo-curing in the vicinity of the interface with the substrate, which is exposed to light, becomes insufficient, and film peeling or the like may occur during development.

Furthermore, the surface of the colored resin is roughened due to the mixing of the coloring material, which causes scattering on the surface of the color filter to deteriorate the optical performance of the color filter. In some cases, the alignment of liquid crystal molecules was disturbed. As a color filter for eliminating such a defect, using a colored resin obtained by dispersing at least a coloring material in a photosensitive resin, in a color filter having a plurality of patterned colored resin layers formed by repeating the photolithography process, There is one in which the coloring material is gradually dispersed from the surface portion to the bottom portion of the colored resin layer.

[0008]

In order to form the above-mentioned color filter on a substrate, a colored resin in which at least a coloring material is dispersed in a photosensitive resin is used and patterned by a photolithography process. In patterning, usually, a colored resin is applied onto a substrate, then temporarily cured by a hot plate or the like, then exposed through a photomask, developed, and then heat-cured to form a color filter pattern.

However, the colored resin of the color filter material is often adhered as a residue on the glass substrate even after development, which causes turbidity of color and deterioration of color characteristics. In order to remove this, it is necessary to wash with water with a brush or the like after the main curing by heating. However, after the washing with water, in the formation of the next color patterning, when the colored resin is applied on the substrate and preliminarily cured by heating, the pattern of the previous color often has floating or peeling, which is a significant yield in color filter production. Was causing the decrease.

The present invention has been made in view of the above-mentioned drawbacks of the prior art. After washing with water for the purpose of removing the residue of the colored resin, heat treatment is again applied to the substrate having the color filter pattern. It is an object of the present invention to improve the adhesiveness of the above, suppress the floating and peeling of the pattern of the previous color at the time of forming the next color, and dramatically improve the manufacturing yield.

[0011]

That is, the present invention provides a method for forming a color filter by applying a colored resin obtained by dispersing at least a colored material in a photosensitive resin onto a substrate and patterning it by a photolithography process. After applying the colored resin on the substrate, heating and temporarily curing it, exposing and developing, then heating and main curing, washing with water to remove the residue left on the substrate, and heat treatment again. It is a method for producing a characteristic color filter.

The present invention will be described in detail below. In the present invention, when a color filter material comprising a colored resin in which at least a coloring material is dispersed in a photosensitive resin is applied on a substrate, a spinner method is usually used as an application method. Next, the applied colored resin film is heated by a hot plate at a uniform temperature to be temporarily cured, exposed by a photomask on which a desired pattern is drawn, and the final exposed portion is developed and removed by a developing solution.

At this time, it is difficult for the unexposed portion to be completely removed by the developing solution, and as a result, the unexposed portion remains as a residue slightly attached to the substrate. Since it is difficult to remove this residue in this state and there is a risk of peeling off the color filter pattern at the same time as the residue, it is removed after the main curing of the pattern.

After development, the substrate is rinsed and heated by a hot plate or a clean oven to be fully cured. After the main curing, remove the residue with a brush while washing with water. After washing with water, it is not possible to sufficiently remove the water molecules that have permeated on the color filter and the interface between the substrate and the filter by a drying method such as an ordinary air blow, and the water remains in this state. When applied and heat-cured, the color filter pattern of the previous color is lifted or peeled off from the substrate due to the influence of water molecules.

Therefore, in the present invention, after the residue removing step, the heat treatment is performed again by the same method and at the same temperature as the heating step at the time of the main curing to remove the remaining water molecules and lift the color filter pattern from the substrate. It is also designed to suppress peeling. The heating temperature in the reheat treatment step is preferably 200 ° C. or higher, and the heat treatment time is preferably 5 minutes or longer.

In the present invention, the photosensitive resin used in the photolithography step is preferably one having excellent durability such as heat resistance, light resistance and solvent resistance in addition to its mechanical characteristics. The durability of the color filter formed using the resin also becomes very good. Further, it is desirable that the temperature is as high as possible in the reheating step after removing the residue, and also from this point of view, it is necessary that the photosensitive resin has excellent heat resistance. Therefore, specific examples from this point of view include photosensitive polyamides and photosensitive polyimides such as Lithocoat PA-1000 (manufactured by Ube Industries, Ltd.) and Lithocoat PI-400 (manufactured by Ube Industries, Ltd.). .

As the coloring material for forming the colored resin layer of the color filter, organic pigments, inorganic pigments,
If the desired spectral characteristics of the dye etc. can be obtained,
It is not particularly limited. In this case, each material can be used alone or a mixture of some of them can be used. However, when a dye is used, the performance of the color filter is governed by the durability of the dye itself, but using the above resin system, it is possible to form a dye that has better performance than an ordinary dye color filter. Is. Therefore, considering the color characteristics and various performances of the color filter, the organic pigment is most desirable as the coloring material.

[0018]

The method for producing a color filter according to the present invention comprises applying a coloring resin obtained by dispersing at least a coloring material in a photosensitive resin onto a substrate, and subjecting it to a usual heat curing, exposure, development, heating main curing or the like. After patterning by the photolithography process, the color filter pattern that has been washed with water to remove the residue is heat-treated again, so that the floating and peeling that are pattern defects of the previous color that occur during the formation of the next color are suppressed, making it an excellent color filter. The pattern can be formed uniformly over the entire surface.

[0019]

EXAMPLES The present invention will be described more specifically below with reference to examples.

Example 1 A blue glass substrate (polished product) having a length of 300 mm, a width of 300 mm and a thickness of 1.1 mm was coated with a polyamide-based colored resin by a spinner method to a film thickness of 18,000 Å. The substrate coated with this colored resin was placed on a hot plate kept at a temperature of 80 ° C. ± 2 ° C. and temporarily cured for 3 minutes. Then, it was exposed and cured by an exposure machine using a photomask on which a color filter pattern was drawn. Further, this was developed with a developing solution to obtain a color filter pattern. At this time, it is difficult to completely remove the unexposed area,
A weak crown residue was generated on the entire surface of the substrate.

In this state, 200 in a clean oven
Main curing was performed by heating at ℃ for 1 hour. Further, the substrate after the main curing was subjected to residue removal in a water bath using a PVA brush. After that, it was reheated in a clean oven at 200 ° C for 1 hour, and when the next color of the colored resin was applied and heat-cured, peeling of the pattern of the previous color and floating were not found at all, and a good color was obtained. A filter pattern was obtained.

In this way, the color filters R (red), G (green) and B (blue) are formed on the substrate, the protective film is provided thereon, and further the transparent electrode (segment electrode) is formed and patterned. Then, a metal electrode for the auxiliary electrode was formed, and an insulating film and an alignment film were formed thereon. A large area display created by bonding this substrate to another counter electrode on which the other common electrode is formed and having a metal electrode, an insulating film and an alignment film formed, and injecting and sealing the ferroelectric liquid crystal There was no unevenness and the color characteristics were also very good.

As the colored resin material, PA-10
12G, PA-1012B, PA-1012R (product of Ube Industries, Ltd.) were used.

FIG. 1 shows the spectral transmittance of the substrate provided with this color filter. Further, FIG. 2 shows a chromaticity diagram of the color filter.

Example 2 A blue-colored glass substrate (polished product) having a length of 300 mm, a width of 300 mm, and a thickness of 1.1 mm was coated with a polyamide-based colored resin by a spinner method to a film thickness of 18,000 Å. The substrate coated with this colored resin was placed on a hot plate kept at a temperature of 80 ° C. ± 2 ° C. and temporarily cured for 3 minutes. Then, it was exposed and cured by an exposure machine using a photomask on which a color filter pattern was drawn. Further, this was developed with a developing solution to obtain a color filter pattern.
At this time, since it is difficult to completely remove the unexposed area, a weak crown residue was generated on the entire surface of the substrate.

In this state, a hot plate at 250 ° C.
The main curing was performed by heating for 5 minutes. Furthermore, the substrate after the main curing is
The residue was removed in a water bath using a VA brush. After that, reheating with a hot plate at 250 ° C. for 5 minutes, applying a coloring resin of the next color and preliminarily curing with heating, no peeling of the pattern of the previous color or floating was observed, and a good color was obtained. A filter pattern was obtained.

In this way, color filters R (red), G (green) and B (blue) are formed on the substrate, a protective film is provided thereon, and further transparent electrodes (segment electrodes) are formed and patterned. Then, a metal electrode for the auxiliary electrode was formed, and an insulating film and an alignment film were formed thereon. A large area display created by bonding this substrate to another counter electrode on which the other common electrode is formed and having a metal electrode, an insulating film and an alignment film formed, and injecting and sealing the ferroelectric liquid crystal There was no unevenness and the color characteristics were also very good.

As the colored resin material, PA-10
12G, PA-1012B, PA-1012R (product of Ube Industries, Ltd.) were used.

[0029]

As described above, according to the present invention,
When a color filter is formed using a photosensitive colored resin, a color that is likely to occur when the next color is formed by reheating at the same temperature as in the main curing step after the residue removal step after heating and main curing. No peeling or floating of the filter pattern occurred, and it was possible to form a uniform pattern having no unevenness and excellent color characteristics over the entire surface of the substrate.

[Brief description of drawings]

FIG. 1 is a diagram showing spectral characteristics of a color filter created by a manufacturing method according to a first embodiment of the present invention.

FIG. 2 is a chromaticity diagram of a color filter created by the manufacturing method according to the first embodiment of the present invention.

Claims (3)

[Claims] 1. A method of forming a color filter by coating a colored resin comprising a photosensitive resin in which at least a coloring material is dispersed on a substrate, and patterning by a photolithography process to form the color filter. A method for producing a color filter, which comprises heat-temporarily curing, exposing and developing, followed by heat-main curing, washing with water to remove residues left on the substrate, and heat treatment again. 2. The method for producing a color filter according to claim 1, wherein the heating temperature in the reheating step is 200 ° C. or higher. 3. The method for producing a color filter according to claim 1, wherein the heat treatment time in the reheat treatment step is 5 minutes or more.