JP3134987B2 - How to prevent color filter color pattern damage - Google Patents

Description

Description: 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 for a liquid crystal display or an image pickup device from being damaged. [0002] This application is a parent application of Japanese Patent Application No. 20731/1985 (Japanese Patent Application No. 69201/1993).
Of the grandchild, whose parent application was “Method for manufacturing color filters” and whose child application was a child, was originally filed in Japanese Patent Application No. 236016 (1995 Patent Application Publication No. 113688). While the applications each relate to a "coating material for a color filter", the grandchild divisional application relates to a simple method of preventing color pattern damage. 2. Description of the Related 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 resin excellent in various resistances such as heat resistance and light resistance (in particular, resistance to ultraviolet light) as a basic material of a color pattern. When a polyimide resin is used as the pattern material, printing or photolithography 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 using a photolithography technique, a technique is known in which each color pattern is formed by patterning and then dyeing as shown in the process flow of FIG. -29225). However, in the conventional technology using this dyeing, the steps are complicated because patterning and dyeing are performed separately, and the patterned polyimide resin is at least semi-cured (semi-cured). There are several disadvantages, such as difficulty in diffusing dyes into Therefore, the present inventors have applied a solution obtained by mixing a coloring material in advance with a polyimide resin solution on a substrate, and applying a colored polyimide resin layer formed by the photolithography technique as a technique for solving such difficulties. A method of patterning was proposed earlier (Japanese Patent Application No. 59-201319). FIG. 4 shows an example of a process flow according to the technology according to the proposal.
It will be appreciated that the process is significantly simplified as compared to that shown in FIG. According to the technique according to the above proposal, each color pattern can be formed relatively easily. However, each time a color pattern is formed, a color pattern formed before that color pattern is formed. A protective film must be formed to protect the pattern. The same applies to the conventional general method shown in FIG. The present inventors have focused on omitting the protective film in order to further simplify the manufacturing process of the color filter, and have made various studies, and have found the following. That is, for example, when a pattern of the second color is formed without covering the pattern of the first color with a protective film, the pattern of the first color is damaged when a coating liquid for the second color is applied. Is hardly damaged at the time of etching. Here, the damage means, for example, cracks or wrinkles in a preceding color pattern such as the first color pattern, or the dye in the first color pattern is dissolved,
Or it is a phenomenon that 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 study results,
It is possible to omit the protective film by adding solvent resistance to the former color pattern, that is, resistance to a solvent that dissolves polyimide. 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 conceivable to increase the temperature to about 250 to 300 ° C. However, when processing at such high temperatures, the choice of dyes for coloring is very limited. An object of the present invention is to provide a method for preventing a color pattern of a color filter from being damaged, which can sufficiently improve the solvent resistance of a preceding (or another) color pattern without significantly increasing the temperature of post baking. Is to provide. According to the present invention, the materials for forming the first and second color patterns having different colors are resin solutions of the same kind, and the resin solutions are made of the same kind of solvent. It was born with the recognition that it included. The first color pattern is a color pattern formed in the preceding stage, and the second color pattern covers the first color pattern so that a layer for forming the second color pattern directly contacts. Another color pattern. In the present invention, basically, a resin solution and a colorant for coloring the resin solution, as well as a surface modifier having an interface migration property or a surface migration property are contained in 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
This 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 not less than ° C., it is dehydrated and ring-closed to obtain a polyimide. In addition, this polyimide precursor solution can be diluted mainly with dimethylacetamide, dimethylformamide, N-methyl-2-pyrrolidone, or the like, and can have appropriate viscosity suitable for spin coating. Various dyes such as azo, anthraquinone, phthalocyanine, carbonium, quinone imine, methine, benzoquinone and naphthoquinone can be used as coloring dyes. One type or two or three types of each dye can be used in combination for each color pattern, but it is preferable to increase the amount of the mixture as much as possible in order to obtain color depth. However, if the amount is too large, there is a disadvantage that it escapes into the photoresist or the stripping agent in a later step. Therefore, it is better to increase the number as far as possible without causing such escape. Next, the key surface modifier is one that imparts solvent resistance to the color pattern, has excellent surface transferability like a perfluoroalkyl group, and has a functional segment having a water-repellent, oil-repellent functional segment. It is a polymer.
In addition to the functional segment, an AB type block polymer of a vinyl monomer having a compatible segment compatible with polyimide, such as an acrylic polymer, has a semipermanent effect of water repellency and oil repellency, Particularly preferred. In addition, as the surface modifier, a functional comb-type graft polymer synthesized by copolymerization of a macromonomer and a functional monomer and having excellent interface transfer properties can be used. Further, as a surface modifier, a functional comb type graft polymer and the above-mentioned block polymer can be mixed and used. The amount of the surface modifier added is usually 1
About 3% is preferable. Increasing the amount of addition tends to increase the effect of water repellency, but for example, 5 to 10%
If it does above, the uniformity of the coating layer for forming a color pattern will fall. Therefore, it is preferable to set the above ratio so that the uniformity of the coating layer is not impaired. By the way, as a substrate of a color filter, that is, a substrate on which a coating material is applied, a general glass plate, a plastic plate or a flexible plastic film, and a semiconductor substrate on which electric elements are formed are also used. can do. In the case of a semiconductor substrate, it is preferable to use a substrate whose surface is flattened by a surface protection film. However, in any case, it is important to increase the adhesion between the substrate and the coating layer in order to increase 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 solution for forming the coating layer. It is valid. According to the present invention, a specific surface modifier is contained in a resin solution for forming a first color pattern touched by the same kind of resin solution, Is the first
The surface of the first color pattern is protected, and the solvent resistance of the first color pattern itself is greatly improved. Therefore, the first (previous stage)
Even if the post bake of the color pattern is processed at a relatively low temperature of, for example, about 230 ° C., the second (next stage)
It can sufficiently withstand the damage caused by the color pattern formation. Generally, color filters are red (R), green (G), blue
In addition to the three primary colors (B), there are four color patterns in which black (Bl) is added. However, the improvement in the solvent resistance is achieved only when the pattern between the first color pattern and the second color pattern is provided. First, the pattern of the second color and the pattern of the third color, and further, between the first color and the second and third colors, and the first color,
The same applies to the second color, the third color, and the fourth color. Therefore, when the present invention is applied, all steps of forming a protective film for protecting the preceding color pattern can be omitted in the process by the photolithography technology as shown in FIG. Further, when the solvent resistance of all the color patterns is increased, it is possible to omit the uppermost protective film, that is, the so-called top coat, which entirely covers all the color patterns. Further, according to the present invention, in addition to simplifying the manufacturing process, it is possible to obtain a thin and flat color filter as a whole because there is no protective film. This will be apparent from FIG. 2 showing the cross-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, epoxy or polyimide material.
G, B, and B1 are red, green, blue, and black color patterns formed by a photolithography technique. A color filter having a cross-sectional structure shown in FIG. 2A is manufactured under the following conditions by using a glass plate coated with silica on the surface as a substrate 1. did. The obtained color filter was of good quality without any damage as described above in the Bl, R and G color patterns at the preceding stage despite the absence of the protective film.
14. A polyimide precursor solution as the first color coating solution:
0 g, metal-containing complex 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
Is prepared and dropped onto one surface of the substrate 1 rotating at 2000 rpm to obtain a black pattern B.
A layer for forming 1 was formed. After pre-baking the layer at 150 ° C. for 30 minutes, it was patterned by photolithography and then post-baked at 240 ° C. for 30 minutes. Next, as a second color coating solution, 10.0 g of a polyimide precursor solution, 0.5 g of an anthraquinone dye (red), 7.0 g of a solvent, 0.04 g of a silane coupling agent, and the same surface as described above. Modifier: A mixed solution containing 0.03 g was prepared, and a black pattern Bl was prepared.
The layer for forming the red pattern R was formed on one surface of the substrate 1 on which the red pattern R was formed under the same conditions as those for the first color. Then, the layer was pre-baked at 145 ° C. for 30 minutes, patterned by photolithography, and then post-baked at 230 ° C. for 30 minutes. Similarly, as the third color coating solution, a polyimide precursor solution: 10.0 g, an azo dye (yellow): 0.8 g, and a carbonium dye (blue): 0.7
g, solvent: 9.0 g, silane coupling agent: 0.03
g, a mixed solution containing the same surface modifier as above: 0.03 g was prepared, and was dropped onto one surface of the substrate 1 rotating at 2500 rpm to form a layer for forming a green pattern G. After pre-baking the layer at 145 ° C. for 30 minutes, it was patterned by photolithography and then post-baked at 200 ° C. for 30 minutes. Further, as a fourth color coating solution, a mixture containing 10.0 g of a polyimide precursor solution, 1.0 g of an azine dye belonging to a quinone imine series (blue), 11.0 g of a solvent, and 0.02 g of a silane coupling agent is used. Prepare the liquid,
This was dropped onto one surface of the substrate 1 rotating at 3000 rpm to form a layer for forming a blue pattern B. After pre-baking the layer at 160 ° C. for 30 minutes, it is patterned in the same manner as other color patterns,
Next, a post bake treatment was performed at 190 ° C. for 30 minutes.
After that, the entire surface of the substrate 1 on which the respective color patterns were formed was covered with the top coat 2. According to the present invention, in addition to the colorant for coloring, the resin solution contains a surface modifier having interface transferability or surface transferability. The solvent resistance of the first color 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 THE DRAWINGS FIG. 1 is a process diagram 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 chart showing a process flow by a conventional general dyeing method. FIG. 4 is a process chart showing a process flow according to the above proposal. [Description of Signs] 1 substrate 2 top coat B blue pattern R red pattern G green pattern Bl black pattern

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Tadahiro Furukawa               4-6-5 Higashikomagata, Sumida-ku, Tokyo                (56) References JP-A-61-180202 (JP, A)

Claims (1)

(57) [Claims] The color pattern of the color filter includes at least first and second color patterns having different colors from each other, and the material for forming the first and second color patterns is made of poly.
Imide precursor and solvent for dilution, and colored
The same type of resin solution containing a colorant for the first color pattern, when the layer for forming the second color pattern is covered so as to be in direct contact with the first color pattern, in the resin solution for forming a Chi also interface migration or surface migration property, and a surface of the first pattern
A method for preventing damage to the color pattern of a color filter, comprising preventing the first color pattern from being damaged by including a surface modifier that makes water repellent oily . 2. Wherein the colorant is a dye, damage prevention method of a color pattern according to claim 1. 3. The surface modifier, repellent and functional segments with water oil repellency, is a A-B type block polymer of a vinyl monomer consisting compatible segment which is compatible to Boriimido of claim 1 or 2 color pattern How to prevent damage. 4. The surface modifying agent is a functional comb graft polymer synthesized by copolymerization of macromonomer with functional monomers, damage prevention method of a color pattern according to claim 1 or 2. 5. The method for preventing damage to a color pattern according to any one of claims 1 to 4 , wherein the amount of the surface modifier added is 1 to 3%. 6. The dye is used by mixing 1 to 3 types,
3. The method for preventing damage to a color pattern according to claim 2 . 7. The method for preventing damage to a color pattern according to claim 2 , wherein at least a metal-containing complex-based dye is used as the black dye. 8. 3. The method according to claim 2 , wherein at least an anthraquinone dye is used as the red dye. 9. As the green dye, a mixture of at least an azo dye and a carbonium dye is used.
Method 2 for preventing damage to the color pattern. 10. 3. The method according to claim 2 , wherein at least a quinone imine-based dye is used as the blue dye.