JP3295156B2 - Photosensitive material for making black matrix substrates - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light-sensitive material for producing a black matrix substrate, and more particularly to a light-sensitive material capable of producing a black matrix substrate having high dimensional accuracy and excellent light-shielding properties by electroless plating.

[0002]

2. Description of the Related Art In recent years, monochrome or color liquid crystal displays have attracted attention as flat displays. Liquid crystal displays include an active matrix system and a simple matrix system for controlling three primary colors, and a color filter is used in each system. In the liquid crystal display, the constituent pixel portion has three primary colors (R, G, B), and transmission of each of the three primary colors is controlled by electrical switching of the liquid crystal to perform color display.

[0003] This color filter is constituted by forming a colored layer, a protective layer and a transparent electrode layer on a transparent substrate. Then, in order to increase the coloring effect and display contrast, a pattern (black matrix) having a light-shielding property is formed at the boundary between the R, G, and B pixels of the colored layer. Further, in an active matrix type liquid crystal display, since a thin film transistor (TFT) is used as a switching element, it is necessary to suppress a light leakage current. For this reason, a high light-shielding property is required for the black matrix.

Conventionally, as a black matrix, those obtained by forming a relief by photoetching a deposited chromium thin film, those obtained by dyeing a hydrophilic resin relief, those formed by using a photosensitive liquid in which a black pigment is dispersed, those formed by black electrodeposition, Some of them were formed by electrodeposition of paint, others were formed by printing, and the like.

[0005]

However, although the above-mentioned chromium thin film formed by photoetching the above-deposited chromium thin film has high dimensional accuracy, it requires a vacuum film-forming process such as vapor deposition and sputtering. Is complicated, the production cost is high, and it is necessary to suppress the reflectance of chromium in order to increase the display contrast under strong external light. Had to do. Further, the method of using a photosensitive resist in which the above black dye or pigment is dispersed,
Although the manufacturing cost is reduced, there is a problem that a high-quality black matrix cannot be obtained, for example, the photo-resist tends to be insufficient because the photosensitive resist is black, and it is difficult to obtain a sufficient light-shielding property. Furthermore, in the black matrix formation by the above-described printing method, although the manufacturing cost can be reduced, there is a problem that the dimensional accuracy is low.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has high flatness and can be used for a flat display such as a liquid crystal display, an imager such as a CCD, or a color filter such as a color sensor. It is an object of the present invention to provide a photosensitive material for producing a black matrix substrate which can be manufactured at low cost by electroless plating.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is configured to be an aqueous solution containing a solid content of polyvinyl alcohol and a diazo resin in a range of 2 to 8% by weight. .

[0008]

The relief for the black matrix formed on the transparent substrate is formed using a photosensitive material containing a solid content of polyvinyl alcohol and a diazo resin in the range of 2 to 8% by weight in an aqueous solution. The surface of the relief is flat without wrinkles, and the subsequent electroless plating uniformly deposits metal particles on the entire relief.The formed black matrix substrate has high flatness, high optical density, and low reflection. Rate.

[0009]

The polyvinyl alcohol used in the light-sensitive material of the present invention is a hydrophilic polyvinyl alcohol. Specific examples include modified polyvinyl alcohol such as a modified sulfone group, a modified acetoacetyl group, a modified cationic group, a modified amide, and a modified carboxyl group, and unmodified polyvinyl alcohol. The polyvinyl alcohol resin has a saponification degree of 65 to 99.9 and an average polymerization degree of 250.
２2800 is preferred.

The diazo resin used for the photosensitive material of the present invention is contained in the photosensitive material as a photocurable photosensitive group. Examples of the diazo resin include a diazo resin having a diazo group and a reaction product of paraformaldehyde.

The solid content of the above-mentioned polyvinyl alcohol and diazo resin is preferably contained in the photosensitive material in the range of 2 to 8% by weight. If the solid content is less than 2% by weight, the viscosity is low and a predetermined film thickness cannot be obtained by conventional coating techniques such as spin coating, dip coating, pouring coating, and roll coating. On the other hand, if the solid content exceeds 8% by weight, the viscosity becomes high and the applicability of the photosensitive material is reduced, and the relief and the flatness of the black matrix deteriorate. On the other hand, the ratio of the diazo resin to the solid content of polyvinyl alcohol and the diazo resin in the photosensitive material is preferably in the range of 2 to 15% by weight. When the ratio of the diazo resin to the solid content is less than 2% by weight, the curing of the photosensitive material becomes insufficient, wrinkles are generated on the coating film surface, and the ratio of the diazo resin to the solid content is 15% by weight. If it exceeds, the nitrogen generation at the time of diazo decomposition increases, and the coating surface of the photosensitive material becomes rough,
In any case, the flatness of the relief and further the black matrix deteriorate.

Further, the photosensitive material of the present invention may contain an inorganic substance such as ceramics or porous alumina, or an organic substance such as a pigment or a polymer. Next, an example of forming a black matrix substrate using the above-described photosensitive material of the present invention will be described with reference to FIG.

First, the photosensitive material of the present invention is coated on a transparent substrate 2 and has a thickness of about 0.1 to 5.0 μm, preferably 0.1 to 5.0 μm.
A photosensitive resist layer 3 having a thickness of about 2.0 μm is formed (FIG. 1A). Next, the photosensitive resist layer 3 is exposed through a photomask 7 for a black matrix (FIG. 1).
(B)). Then, the exposed photosensitive resist layer 3 is developed to form a relief 4 having a pattern for a black matrix (FIG. 1C). Next, the transparent substrate 2 is immersed in an aqueous solution of a metal compound serving as a catalyst for electroless plating, washed with water and dried, and then subjected to a heat treatment (100 to 200 ° C., 5 to 5 ° C.).
(30 minutes) to obtain a catalyst-containing relief 5 (FIG. 1).
(D)). Then, the catalyst-containing relief 5 on the transparent substrate 2
Is brought into contact with an electroless plating solution to form a black relief, and a black matrix 6 is formed.
(E)). The heat treatment may be performed at the stage of the relief 4 before forming the catalyst-containing relief 5. The heat treatment conditions in this case are preferably 90 to 130 ° C. for about 5 to 60 minutes. The black matrix 6 may be subjected to a hardening treatment by heating or applying a hardener.

As the metal compound serving as a catalyst for electroless plating used for forming the black matrix, for example, chlorides such as palladium, gold, silver, platinum and copper, water-soluble salts such as nitrates and complex compounds are used. Alternatively, an activator solution for electroless plating, which is commercially available as an aqueous solution, can be used as it is or after dilution. Incidentally, such a metal compound may be contained in the light-sensitive material of the present invention. In this case, the content is preferably about 0.00001 to 0.001% by weight.

The electroless plating solution that can be used for forming the above black matrix includes, for example, reducing agents such as hypophosphorous acid, sodium hypophosphite, sodium borohydride, N-dimethylamine borane, borazine derivatives, hydrazine and formalin. And, for example, water-soluble reducible heavy metal salts such as nickel, cobalt, iron, copper and chromium, and basic compounds such as caustic soda and ammonium hydroxide for improving plating speed and reduction efficiency, and inorganic acids and organic acids. PH adjusting agents, such as sodium citrate, sodium acetate, etc., and buffering agents represented by alkali salts of boric acid, carbonic acid, organic acids, and inorganic acids, and complexing for the purpose of stabilizing heavy metal ions. An electroless plating solution having a reaction accelerator, a stabilizer, a surfactant and the like in addition to the agent is used.

Further, two or more kinds of electroless plating solutions may be used in combination. For example, first, using an electroless plating solution containing a boron-based reducing agent such as sodium borohydride, which easily forms a nucleus (for example, a nucleus of palladium when palladium is used as a metal compound serving as a catalyst for electroless plating), Next, an electroless plating solution containing a hypophosphorous acid-based reducing agent having a high metal deposition rate can be used.

The black matrix substrate 1 as described above
Various known methods such as a dyeing method, a dispersing method, a printing method, and an electrodeposition method can be used to form a colored layer including a red pattern, a green pattern, and a blue pattern between the black matrices 6.

In order to produce a color filter, a protective layer is provided so as to cover the black matrix 6 produced as described above and the coloring layer, to smooth the surface of the color filter, to improve the reliability, and to provide a liquid crystal layer. It is possible to prevent contamination of the air. This protective layer can be formed using a transparent resin such as an acrylic resin, an epoxy resin, or a polyimide resin, or a transparent inorganic compound such as silicon dioxide. The thickness of the protective layer is preferably about 0.5 to 50 μm.

Further, on the protective layer, for example, an indium tin oxide (ITO) film can be formed as a transparent common electrode. The ITO film can be formed by a known method such as a vapor deposition method and a sputtering method, and has a thickness of 200 to 200.
About 0 ° is preferable.

Next, the present invention will be described in more detail with reference to experimental examples. (Experimental example) First, using polyvinyl alcohol (Gosenal T-330 manufactured by Nippon Synthetic Chemical Industry Co., Ltd.) and diazo resin (D-011 manufactured by Shinko Giken Co., Ltd.), polyvinyl alcohol and diazo resin were used as shown in Table 1 below. Nine kinds of aqueous solutions (photosensitive materials) were prepared by changing the solid content and the ratio of the diazo resin to the solid content.

Next, as a transparent substrate, a Corning 70
Each of the photosensitive materials shown in Table 1 was applied to a transparent substrate by a spin coating method (rotation speed = 1600 rpm) using 59 glass (thickness = 1.1 mm).
The photosensitive resist layer (thickness = 0.6 μm) was formed by drying at 10 ° C. for 10 minutes.

Next, a photomask (line width = 2) for a black matrix is applied to the nine types of photosensitive resist layers.
0 μm). The light source for exposure was an ultra-high pressure mercury lamp of 2 kW, and irradiation was performed for 10 seconds. Thereafter, spray development is performed using water at room temperature, and after spin drying, 10
A heat treatment at 0 ° C. for 30 minutes was performed to form a relief having a line width of 20 μm for a black matrix.

Next, the transparent substrate was immersed in an aqueous palladium chloride solution (Red Sumer, manufactured by Nippon Kanigen) for 30 seconds, washed with water and dried to obtain a catalyst-containing relief.

Thereafter, the transparent substrate is immersed in a nickel plating solution containing a boron-based reducing agent at 30 ° C. (nickel plating solution top chemialloy B-1 manufactured by Okuno Pharmaceutical Co., Ltd.) for 4 minutes, washed with water and dried, and then dried at 200 ° C. for 60 minutes. To form a black relief (black matrix).

Table 1 shows the results of evaluating the quality of the black matrix prepared using the nine types of photosensitive materials as described above.

[0026]

[Table 1] As shown in Table 1, a photosensitive material comprising polyvinyl alcohol and a diazo resin having a solid content of less than 2% by weight (N
o. 6) and photosensitive material exceeding 8% by weight (No. 7)
Did not provide a good quality black matrix. The photosensitive material No. 8 and No. From the evaluation result of the black matrix using No. 9, it is considered that the ratio of the diazo resin to the solid content is preferably about 2 to 15% by weight.

Next, a color filter was formed by forming a colored layer, a protective layer and a transparent electrode on a black matrix substrate of the kind described above. First, the colored layer is formed on the black matrix layer by a spin coating method (rotation speed = 1200
rpm) to apply a red photosensitive resin (MR-G (R) manufactured by The Inktech Co., Ltd.). Then 70
Drying (prebaking) was performed at 30 ° C. for 30 minutes to form a red photosensitive resin layer (film thickness = 1.2 μm).

Next, a photomask for red pixels (line width =
(100 μm), and then exposure was performed through this photomask. The exposure apparatus used was a proximity exposure apparatus manufactured by Dainippon Screen Co., Ltd., and the exposure amount was 150 mJ / cm ² . Thereafter, shower development (development time = 60 seconds) is performed using water at normal temperature, and then,
Heat treatment (post-baking) at 150 ° C. for 30 minutes was performed to form red pixels.

The same steps were repeated to form a colored layer composed of red, green and blue pixels. The conditions for forming each pixel were in accordance with the conditions shown in Table 2 below.

[0030]

[Table 2] Next, to form a protective layer, a coating solution having the composition shown below was applied on the colored layer by spin coating (rotation speed = 1500 rpm) (film thickness = 2.0 μm).

(Composition of Coating Liquid for Forming Protective Layer) Photocurable acrylate oligomer (o-cresol novolak epoxy acrylate (molecular weight 1500 to 2000)) 35 parts by weight Cresol novolak epoxy resin 15 parts by weight Many Functional polymerizable monomer (dipentaerythritol hexaacrylate (DPHA manufactured by Nippon Kayaku)) 50 parts by weight Polymerization initiator (Irgacure manufactured by Ciba Geigy) 2 parts by weight Epoxy curing agent (UVE1014 manufactured by General Electric) 2 Part by weight-Ethyl cellosolve acetate ... 200 parts by weight Then, using a proximity exposure apparatus manufactured by Dainippon Screen Co., Ltd., an exposure amount of 150 mJ is applied to this coating film.
/ Cm ² was used to perform overall exposure. Then, the substrate is brought to room temperature at 1,
It was immersed in 1,2,2-tetrachloroethane for 1 minute to remove only the uncured portion of the coating film, thereby forming a protective film.

Further, 0.4 μm thick indium tin oxide (ITO) is formed on the protective film by a sputtering method.
A film was formed into a transparent electrode to obtain a color filter. Further, a colored layer was formed by a printing method as described below to prepare a color filter. That is, a plate depth of 6 μm and a width of 110
The following ink compositions S-1, S-2, and S-3 were placed in this order between black matrices on a black matrix substrate by intaglio offset printing using a plate having μm stripe-shaped concave portions and a silicone blanket. Print in blue, green and red respectively
A stripe pattern having a width of 0 μm was formed by printing. Thereafter, the ink composition was thermally cured by heating the substrate at 200 ° C. for 30 minutes to obtain a colored layer having a thickness of 2 to 3 μm.

Varnish composition Polyester acrylate resin (Toa Gosei Chemical Industry Co., Ltd. Aronix M-7100) 70 parts by weight Diallyl phthalate prepolymer 30 parts by weight Composition of ink composition (S-1) Varnish 100 Parts by weight ・ Pigment (Lionol Blue ES) (manufactured by Toyo Ink Mfg. Co., Ltd., CI Pigment Blue 15: 6) ... 15.5 parts by weight ・ Pigment (Lionogen Violet RL) (manufactured by Toyo Ink Mfg. Co., Ltd., CIigment Vioet 23) 4 parts by weight Composition of ink composition (S-2) Varnish 100 parts by weight Pigment (Lionol Green 2YS) (CIPigmentGreen 36 manufactured by Toyo Ink Mfg. Co., Ltd.) 22 parts by weight Pigment ( Seika Fast Yellow 2700) (Dainichiseika Color & Chemicals Mfg. Co., Ltd., CI Pigment Yellow 83) ... composition varnish ... 100 weight 7.5 parts by weight ink composition (S-3)・ Pigment (Chromophthal Red A3B) (Ciba Geigy Co., CI Pigment Red 177) 32 parts by weight ・ Pigment (Secastar Yellow 2700) (Dainichi Seika Kogyo Co., Ltd., C.Pigment Yellow 83) 8 parts by weight Next, a protective layer and a transparent electrode were formed as described above to obtain a color filter.

Of the color filters thus created,
No. 1 to No. The one prepared using a black matrix substrate using the photosensitive material of No. 5 exhibited a high coloring effect and a high display contrast when used in a color liquid crystal display. However, no. 6-No. In the case of using a black matrix substrate using the photosensitive material of No. 9, when used in a color liquid crystal display, the coloring effect and the display contrast were insufficient.

[0035]

As described in detail above, according to the present invention, the light-sensitive material is an aqueous solution containing a solid content of polyvinyl alcohol and a diazo resin in the range of 2 to 8% by weight. The surface of the black matrix relief formed on the transparent substrate is flat without wrinkles, metal particles are uniformly deposited on the entire relief by electroless plating, and the formed black matrix substrate has high flatness, The optical density is high and the reflectance is low.

[Brief description of the drawings]

FIG. 1 is a process chart for explaining an example of forming a black matrix substrate using the photosensitive material of the present invention.

[Description of Signs] 1 ... Black matrix substrate 2 ... Transparent substrate 3 ... Photosensitive resist layer 4 ... Relief 5 ... Catalyst-relief 6 ... Black matrix (black relief)

Claims (1)

(57) [Claims] 1. A solid content comprising polyvinyl alcohol and a diazo resin in a range of 2 to 8% by weight , and
The ratio of the diazo resin to the solid content is 2 to 15% by weight.
A photosensitive material for producing a black matrix substrate, which is an aqueous solution within a range .