JPH05134112A - Formation of color filter board - Google Patents

Abstract

PURPOSE:To improve super fine processibility (patterning property) of a transparent conductive film by making a resin protective film have a layered structure and forming the most upper layer of the resin protective film from a layer of mainly polyimide resin. CONSTITUTION:A color filter 4 is formed on a transparent substrate 4, and after a resin protective film consisting of two layers of a layer 3 of acrylate, etc., and a layer 2 of polyimide is formed on it, a transparent conductive film 1 of ITO is formed. In this case, the most upper layer 2 of the resin protective layer which consists of mainly polyimide resin and is formed to improve the adhesive strength of the transparent conductive film 1 is preferably to be >=0.01mum <=0.5mum thick. As the color filter 4, which is not specifically specified, ones made of gelatine, etc., by dyeing method, ones made of polyimide resin, acrylic resin, polyamide resin, etc., by photolithographic method, ones made of acrylic resin by printing method, ones made of melamine resin by electrodeposition, etc., are used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of forming a color filter substrate with a transparent electrode for use in a color display device.

[0002]

2. Description of the Related Art The structure of a color filter substrate with a transparent conductive film used in a color liquid crystal display device is roughly
It has a laminated structure of a transparent substrate / color filter / resin protective film / transparent electrode. The resin protective film is indispensable for 1) compensation (smoothing) of the steps inside and between the colors of the color filter, and 2) protection of the color filter from chemicals and heat that are exposed in the subsequent process.

For the transparent electrode, a transparent conductive metal compound thin film typified by a tin-doped indium oxide (ITO) thin film is formed on the resin protective film by a PVD method such as a sputtering method or a vacuum deposition method. It is general to perform fine processing (patterning) through a photolithography process / wet etching process. However, depending on the composition of the resin protective film and the film forming conditions of the transparent conductive metal compound thin film, sufficient adhesive force between the resin protective film and the transparent conductive metal compound thin film cannot be obtained, and the transparent conductive metal compound thin film is patterned. Peeling occurs,
There was a problem such as severe undercut and side etch.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art, in which a polyimide resin is arranged on the uppermost layer of a resin protective film, and a transparent conductive film and a resin are provided. It is an object of the present invention to provide a method for improving the adhesion of a protective film and improving the electrode characteristics and reliability of a transparent electrode.

[0005]

That is, according to the present invention, a polyimide resin having high adhesiveness to a transparent conductive film is arranged on the uppermost surface of the resin protective film which is in direct contact with the transparent conductive film, The present invention provides a method for forming a color filter substrate with a transparent electrode having high electrode characteristics and high reliability as a result.

FIG. 1 is a sectional view of a color filter substrate of the present invention. 1 is a transparent conductive film that is subjected to patterning treatment, 2 is a resin protective film uppermost layer containing polyimide resin as a main component, 3 is a resin protective film lower layer, 4 is a color filter, 5
Is a transparent substrate.

As a typical example of the transparent conductive film 1 of the present invention, a thin film of indium oxide (ITO) doped with Sn, SnO ₂ doped with F or Sb, ZnO doped with Al, Si, B or the like is given. However, other metal compound thin films may be used. The method for forming the transparent conductive film is not particularly limited, but considering the heat resistance of the color filter 4 and the resin protective film, a magnetron sputtering method capable of forming a high-performance film at a relatively low temperature or a high-density plasma is used. The vapor deposition method described above is preferred.

The resin protective film lower layer 3 of the present invention includes, but is not limited to, a material containing at least one of transparent resins such as acrylic resin and silicone resin as a main component. In addition, the film thickness of the entire resin protective film is generally 1 μm to 10 μm.

In the present invention, the film thickness of the resin protective film uppermost layer 2 containing polyimide resin as a main component, which is provided for improving the adhesive force of the transparent conductive film, is 0.01 μm or more,
It is preferably 0.5 μm or less. If it is thinner than 0.01 μm, a sufficient effect cannot be obtained, and if it is thicker than 0.5 μm, a problem may occur in the adhesive force with the resin protective film lower layer 3. However,
Before the resin protective film uppermost layer 2 is applied, the surface of the resin protective film lower layer 3 is activated by UV (ultraviolet) irradiation, so that the resin protective film uppermost layer 2 is wettable and adheres to the resin protective film lower layer 3. Tends to improve.

Examples of methods for forming the uppermost resin protective film layer 2 and the lower resin protective film layer 3 include spin coating, roll coating, printing, dipping, and spraying.

The color filter 4 is not particularly limited, and is made of gelatin or the like by the dyeing method, polyimide resin, acrylic resin, polyamide resin or the like formed by photolithography, or the acrylic resin or the like by the printing method. Any of those made of melamine resin by the electrodeposition method, etc. can be used.

[0012]

In the present invention, the mechanism of action for improving the adhesive force of the transparent conductive film of the resin protective film containing polyimide resin as the main component is not always clear, but the bond between the functional group of the polyimide resin and the transparent conductive film is not so clear. It is considered that the above-mentioned effects are caused by the chemical relationship of the hands.

[0013]

Example A color filter 4 having a thickness of 2 μm was formed on a transparent glass substrate 5 by a printing method, and an acrylic resin as a lower layer 3 of a resin protective film was coated thereon with a thickness of 3 μm by a spin coating method. Further, after activating the surface of the resin protective film lower layer 3 by UV irradiation, a polyimide resin as the resin protective film uppermost layer 2 is applied by a spin coater and thermally cured to complete the formation of the resin protective film of the color filter. ..

As the transparent conductive film 1 to be processed as a transparent electrode, an ITO thin film having a thickness of 0.25 μm was formed on the resin protective film by magnetron sputtering.

After applying a line-shaped resist (masking agent) on the ITO film, it is immersed in a hydrochloric acid / ferric chloride-based etching solution (etchant) to perform fine processing (patterning) of the ITO film. It was As a result, the amount of side etching of the ITO film on the resin protective film (the amount by which the etching progressed and became thinner than the width of the masking agent) was 1 μm or less, which showed good patterning characteristics.

[Comparative Example] With a structure in which the resin protective film upper layer 2 was not provided (that is, a structure in which an ITO thin film was formed directly on an acrylic resin), the ITO film was patterned under the same conditions as in the above experimental example. In this case, the side etching amount was as large as 4 to 7 μm, and the patterning characteristics were significantly inferior to the experimental examples.

[0017]

According to the present invention, in the color filter substrate with a transparent electrode, the resin protective film has a laminated structure of at least two layers, and the uppermost layer 2 of the resin protective film in contact with the transparent electrode film contains polyimide resin as a main component. By comprising a layer, the adhesive force between the transparent conductive film 1 and the resin protective film is improved,
It has an excellent effect that the fine processing characteristics (patterning) characteristics of the transparent conductive film are improved, and particularly has an effect that problems such as side etching are solved.

[Brief description of drawings]

FIG. 1 is a sectional view of an example of a color filter substrate according to the present invention.

[Explanation of symbols]

 1 transparent conductive film 2 resin protective film uppermost layer 3 resin protective film lower layer 4 color filter 5 transparent substrate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takeshi Harano 1150 Hazawa-machi, Kanagawa-ku, Yokohama, Kanagawa Prefecture Asahi Glass Co., Ltd. Central Research Laboratory (72) Inventor Kenji Matsuhiro 1150, Hazawa-machi, Kanagawa-ku, Yokohama Asahi Glass Central Research Institute Co., Ltd.

Claims (6)

[Claims] 1. A method for forming a color filter substrate in which a color filter, a resin protective film and a transparent conductive film are sequentially formed on a transparent substrate, wherein the resin protective film has a laminated structure of at least two layers, of which a transparent electrode film. A method of forming a color filter substrate, wherein the uppermost layer of the resin protective film in contact with is a layer containing a polyimide resin as a main component. 2. The film thickness of the uppermost layer of the resin protective film is 0.01 μm.
The method for forming a color filter substrate according to claim 1, wherein the thickness is about 0.5 μm. 3. The color according to claim 1, wherein the lower layer of the resin protective film, which is in contact with the color filter, of the resin protective film is a layer containing at least one of acrylic resin and silicone resin as a main component. A method for forming a filter substrate. 4. The film thickness of the entire resin protective film is 1 μm to 10 μm.
The method for forming a color filter substrate according to any one of claims 1 to 3, wherein m is m. 5. The method for forming a color filter substrate according to claim 1, wherein UV irradiation is performed during a step of laminating each layer constituting the resin protective film. 6. The transparent conductive film comprises Sn-doped indium oxide (ITO), F or Sb-doped SnO ₂ , A.
Zn doped with at least one of l, Si and B
6. The method for forming a color filter substrate according to claim 1, wherein the color filter substrate is one of O.