JPH09297212A - Method to prevent damage in color pattern of color filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve solvent resistance of a first color pattern without increasing the temp for postbaking so much by incorporating a coloring agent and a surface reforming agent having mobility to the interface into a resin soln. to form a first color pattern. SOLUTION: The material to form a first color patterns is the same kind of resin soln. for the material to form a second color pattern. When a layer to form the second color pattern is directly applied to cover the first color pattern, the solvent resistance of the first color pattern itself can be greatly improved by incorporating a surface reforming agent having mobility to the interface or the surface into the resin soln. to form the first color pattern. Thereby, even when the first color pattern after patterned is subjected to post baking, for example, at about 230 deg.C, the first pattern has enough durability against damages during the second color pattern is formed. The solvent resistance can be also improved between color patterns of four colors of red(R), green(G), blue(B) and black(Bl).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for preventing a color pattern of a color filter used in a liquid crystal display or an image pickup device from being damaged.

[0002]

[Related Application] This application is the parent application of Japanese Patent Application No. 20731 in 1985 (Japanese Patent Application Publication No. 69201 in 1993).
No.), which is a grandchild's application whose original application is 1994 Patent Application No. 236,016 (1995 Patent Application Publication No. 113688), and the parent application is “color filter manufacturing method” The application relates to "coating materials for color filters", respectively, whereas the subdivision application of the grandchild relates to a simple method of preventing damage to the color pattern.

[0003]

BACKGROUND ART A color filter of this type has a plurality of color patterns on one surface of a substrate such as a glass plate. In order to increase the resistance of the color filter, it is effective to increase the resistance of each color pattern itself. Conventionally, it has been known to use a polyimide-based resin excellent in various resistances such as heat resistance and light resistance (especially resistance to ultraviolet rays) as a basic material of a color pattern. When a polyimide resin is used as a pattern material, a printing or photolithography technique is used as the patterning method. Although the former printing is simple, the latter photolithography technique is far superior in terms of surface accuracy and dimensional accuracy of the obtained pattern. As a conventional example based on the photolithography technique, there is known a technique in which each color pattern is formed by dyeing after patterning as shown in the process flow of FIG. 3 (for example, JP-A-59). -292225). However, in the conventional technique utilizing this dyeing, the process is complicated because the patterning and the dyeing are performed separately, and the patterned polyimide resin is at least in a semi-cure state. There are some drawbacks, such as difficulty in diffusing the dye. Therefore, the present inventors, as a technique for solving such difficulties, a solution prepared by mixing a colorant into a polyimide-based resin solution in advance is applied on a substrate, and the colored polyimide resin layer formed thereby is formed by a photolithography technique. A patterning method was previously proposed (Japanese Patent Application No. 59-201319). FIG. 4 shows an example of a process flow according to the proposed technique.
It will be appreciated that the process is considerably simplified compared to that shown in.

[0004]

According to the technique proposed above, each color pattern can be formed relatively easily, but each time the color pattern is formed, the color pattern formed before is protected. In order to do so, a protective film must be formed. The same applies to the conventional general method shown in FIG. The inventors of the present invention have made various investigations by paying attention to the omission of the protective film in order to further simplify the manufacturing process of the color filter. That is, for example, when the pattern of the second color is formed without covering the protective film on the pattern of the first color, the pattern of the first color is damaged when the coating liquid for the second color is applied. It means that it is hardly damaged during etching. Here, the damage means, for example, cracks or wrinkles occur in a color pattern in the preceding stage such as the pattern of the first color, further, the dye in the pattern of the first color melts,
Alternatively, it is a phenomenon in which the pattern itself melts out. It is considered that such a phenomenon is caused by the solvent contained in the coating liquid for the second color. According to the above examination results,
It is possible to omit the protective film by adding solvent resistance, that is, resistance to a solvent that dissolves polyimide, to the color pattern in the preceding stage. As a method of increasing the solvent resistance of the pattern, the temperature of the post bake after etching is as high as possible within the range where the heat resistance of the dye is allowed,
For example, it is possible to raise the temperature to about 250 to 300 ° C. However, when treated at such high temperatures, the choice of dyes for coloring is very limited. An object of the present invention is a method for preventing damage to a color pattern of a color filter, which can sufficiently improve the solvent resistance of the color pattern of the first stage (in other words, the first) without increasing the temperature of the post bake so much. To provide.

[0005]

The present invention recognizes that the materials forming the first and second color patterns having mutually different colors are resin solutions of the same kind, and those resin solutions contain the same kind of solvent. Was born under. The first color pattern is a color pattern to be formed in the preceding stage, and the second color pattern covers the first color pattern so that the layer for forming the second color pattern is in direct contact. Another color pattern. In the present invention, basically, in addition to the resin solution and the colorant for coloring the same, a surface modifier having an interfacial migration property or a surface migration property is contained in the material forming the first color pattern. The resin solution preferably contains a polyimide precursor and a solvent for dilution, and the colorant is preferably a dye. The solution of the polyimide precursor is
A solution containing a polyamic acid in a highly polar solvent such as N-methyl-2-pyrrolidone.
When baked at a high temperature of ℃ or more, dehydration ring closure occurs to polyimide. The polyimide precursor solution can be diluted mainly with dimethylacetamide, dimethylformamide, N-methyl-2-pyrrolidone or the like, and can have an appropriate viscosity suitable for spin coating. As the dye for coloring, various dyes such as azo, anthraquinone, phthalocyanine, carbonium, quinone imine, methine, benzoquinone and naphthoquinone can be used. Each dye may be used alone or as a mixture of a few dyes for each color pattern, but it is preferable to increase the mixing amount as much as possible in order to bring out the color strength. However, if the amount is too large, there is a disadvantage that it escapes into the photoresist or the release agent in a later step. Therefore, it is good to make as much as possible within the range where such escape does not occur. Next, the surface modifier, which is the key point, imparts solvent resistance to the color pattern, and is a block that has a functional segment that has excellent surface migration like perfluoroalkyl groups and has water and oil repellency. It is a polymer.
In addition to the functional segment, the AB type block polymer of a vinyl monomer that also has a compatible segment compatible with polyimide, such as an acrylic polymer, has a semi-permanent water-repellent and oil-repellent effect. Particularly preferred. Further, as the surface modifier, a functional comb-type graft polymer synthesized by copolymerization of a macromonomer and a functional monomer and having excellent interfacial migration can also be used. Further, as the surface modifier, a functional comb-type graft polymer and the block polymer may be mixed and used. The amount of the surface modifier added is usually 1
About 3% is preferable. If the amount of addition is increased, the effect of oil and water repellent tends to increase, but for example, 5 to 10%
In the above case, the uniformity of the coating layer for forming the color pattern is reduced. Therefore, it is preferable to set the above ratio so that the uniformity of the coating layer is not impaired. By the way, as the substrate of the color filter, that is, the substrate on which the coating material is applied, in addition to a general glass plate, a plastic plate or a flexible plastic film, and a semiconductor substrate on which an electric element is formed can also be used. can do. In the case of a semiconductor substrate, it is preferable to use a substrate whose surface is flattened by a surface protective film. However, in any case, increasing the adhesion between the substrate and the coating layer is important for improving the patterning accuracy and the like. When a glass plate is used as the substrate, an additive for improving adhesion such as a silane coupling agent such as N-phenyl-γ-aminopropyltrimethoxysilane may be added to the mixed liquid for forming the coating layer. It is valid.

[0006]

[Operation] In the present invention, a specific surface modifier is contained in the resin solution for forming the first color pattern which is in contact with the same kind of resin solution, and the surface modifier is the first
The color pattern shifts to the surface layer portion to protect the surface, and the solvent resistance of the first color pattern itself is significantly improved. Therefore, the patterned first (previous)
Even if the post baking of the color pattern is processed at a relatively low temperature of about 230 ° C., the second (next stage)
It can withstand the damage caused by color pattern formation. Generally, color filters are red (R), green (G), and blue.
In addition to the three primary colors of (B), it has a color pattern of four colors to which black (Bl) is added, but the improvement in solvent resistance is only between the pattern of the first color and the pattern of the second color. The second color pattern and the third color pattern, further between the first color and the second color and the third color, and the first color,
The same applies to the second and third colors and the fourth color. Therefore, if the present invention is applied, it is possible to omit all the steps of forming a protective film for protecting the color pattern in the previous stage, as shown in the flow chart of FIG. Further, when the solvent resistance of all the color patterns is increased, it is possible to omit the so-called top coat, which is the uppermost protective film that entirely covers all the color patterns. Furthermore, according to the present invention, in addition to simplifying the manufacturing process, since there is no protective film, it is possible to obtain a thin and flat color filter as a whole. This will be apparent from FIG. 2 showing the sectional structure of the color filter obtained by applying the present invention. In FIG. 2, 1 is a substrate made of a glass plate, 2 is a top coat made of a gelatin-based, epoxy-based or polyimide-based material, and R,
G, B, and Bl are red, green, blue, and black color patterns formed by the photolithography technique.

[0007]

Example to which the present invention is applied A glass plate having a surface coated with silica was used as a substrate 1, and a color filter having the cross-sectional structure of FIG. 2A was manufactured under the following conditions. The obtained color filter was of a good quality in which the above-mentioned Bl, R and G color patterns were not damaged at all, even though there was no protective film.
As a first color coating liquid, a polyimide precursor solution: 15.
0 g, metal-containing complex salt dye (black): 1.0 g, solvent: 1
0.0 g, silane coupling agent: 0.06 g, surface modifier containing perfluoroalkyl group as one component: 0.05 g
A mixed liquid containing B is prepared and dropped on one surface of the substrate 1 rotating at 2000 rpm to obtain a black pattern B.
A layer for forming 1 was formed. The layer was prebaked at 150 ° C. for 30 minutes, then patterned by photolithography techniques, and then post baked at 240 ° C. for 30 minutes. Next, as a second color coating liquid, a polyimide precursor solution: 10.0 g, anthraquinone dye (red): 0.5 g, a solvent: 7.0 g, a silane coupling agent: 0.04 g, the same surface as above Prepare a mixed solution containing a modifier: 0.03 g, and use a black pattern Bl.
A layer for forming a red pattern R was formed on one surface of the substrate 1 on which was formed by applying under the same conditions as the first color. Then, the layer was pre-baked at 145 ° C. for 30 minutes, patterned by a photolithography technique, and then post-baked at 230 ° C. for 30 minutes. Similarly, as a third color coating liquid, a polyimide precursor solution: 10.0 g, an azo dye (yellow): 0.8 g, a carbonium dye (blue): 0.7
g, solvent: 9.0 g, silane coupling agent: 0.03
g, a mixed solution containing 0.03 g of the same surface modifier as described above was prepared, and the mixed solution was dropped onto one surface of the substrate 1 rotating at 2500 rpm to form a layer for forming the green pattern G. The layer was pre-baked at 145 ° C. for 30 minutes, then patterned by photolithography techniques and then post-baked at 200 ° C. for 30 minutes. Further, as a coating liquid for the fourth color, a mixture containing a polyimide precursor solution: 10.0 g, a quinone imine-based azine dye (blue): 1.0 g, a solvent: 11.0 g, and a silane coupling agent: 0.02 g Prepare the liquid,
This was dropped onto one surface of the substrate 1 rotating at 3000 rpm to form a layer for forming the blue pattern B. After pre-baking the layer for 30 minutes at 160 ° C., patterning as for other color patterns,
Then, a post-baking treatment was performed at 190 ° C. for 30 minutes.
Then, after this, the entire one surface of the substrate 1 on which each color pattern was formed was covered with the top coat 2.

[0008]

EFFECTS OF THE INVENTION In the present invention, the resin solution contains not only a coloring agent for coloring but also a surface modifier having an interfacial migration property or a surface migration property. The solvent resistance of the pattern can be sufficiently improved. Therefore, even when a resin solution of the same type as the resin solution of the first color pattern directly contacts the first color pattern, it is possible to effectively prevent the first color pattern from being damaged by the solvent. it can.

[Brief description of drawings]

FIG. 1 is a process chart showing an example of a process flow to which the present invention is applied.

FIG. 2 is a cross-sectional view showing each example of a color filter obtained by applying the present invention.

FIG. 3 is a process diagram showing a process flow by a conventional general dyeing method.

FIG. 4 is a process diagram showing a process flow according to the above proposal.

[Explanation of symbols]

 1 substrate 2 top coat B blue pattern R red pattern G green pattern Bl black pattern

Claims (11)

[Claims] 1. The color pattern of a color filter includes at least first and second color patterns having mutually different colors, and materials forming the first and second color patterns are resin solutions of the same kind, When the first color pattern is covered with the layer for forming the second color pattern so as to be in direct contact with the first color pattern, the interface solution is transferred into the resin solution for forming the first pattern. Alternatively, a method for preventing damage to the color pattern of the color filter is characterized by preventing the damage to the first color pattern by including a surface modifier having surface migration property. 2. The color pattern of claim 1, wherein the resin solution for forming each of the first and second color patterns includes a polyimide precursor, a solvent for dilution, and a colorant for coloring. Damage prevention method. 3. The color pattern damage prevention method according to claim 2, wherein the colorant is a dye. 4. The surface modifying agent is an AB type block polymer of a vinyl monomer comprising a functional segment having water and oil repellency and a compatible segment compatible with polyimide. Alternatively, the color pattern damage prevention method of 3. 5. The color pattern damage prevention method according to claim 2, wherein the surface modifier is a functional comb-type graft polymer synthesized by copolymerization of a macromonomer and a functional monomer. 6. The method for preventing damage to a color pattern according to claim 1, wherein the amount of the surface modifier added is 1 to 3%. 7. The method for preventing damage of a color pattern according to claim 3, wherein the dye is used by mixing one to three kinds of dyes. 8. The method for preventing damage to a color pattern according to claim 3, wherein at least a metal-containing complex salt-based dye is used as the black dye. 9. The method for preventing damage to a color pattern according to claim 3, wherein at least anthraquinone dye is used as the red dye. 10. The method for preventing damage to a color pattern according to claim 3, wherein a mixture of at least an azo dye and a carbonium dye is used as the green dye. 11. The method for preventing damage of a color pattern according to claim 3, wherein at least a quinoneimine dye is used as the blue dye.