JPH0612451B2 - Corrosion resistant photosensitive film - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a corrosion-resistant photosensitive film used for etching a metal plate by a light exposure method.

TECHNICAL BACKGROUND OF THE INVENTION A light exposure method is used as a method for etching a predetermined pattern on a metal plate. For example, in the case of forming a large number of fine apertures such as a sheer mask used for a color picture tube,
An ordinary low carbon steel plate or a metal thin plate such as an iron-nickel alloy or a copper-nickel alloy is used, and a corrosion-resistant photosensitive film is applied and dried on both surfaces of the metal plate to form a resist film having a constant film thickness. To form. Then, this resist film is exposed through a predetermined mask pattern by a contact printing method or the like. Next, the exposed portion is made insoluble in a specific solvent, and the baked resist film is developed to dissolve and remove the unexposed portion, and then heated so that the remaining resist film has etching resistance. After that, an exposed portion of the metal surface not covered with the residual resist film is etched with an etching liquid such as ferric chloride. After the predetermined opening is formed, the residual resist film is removed. As the anticorrosion photosensitive film used for etching a metal plate by such a light exposure method, those containing polyvinyl alcohol and alkali dichromate, casein and alkali dichromate, and gleux and alkali dichromate are conventionally used. .

However, in the case of the above-mentioned anticorrosion photosensitive film, since it is a synthetic product, it is possible to always use a stable quality one, but the dissolved resist at the time of development is completely removed from the surface of the metal plate. Very difficult to wash off. For example, as shown in FIG. 1 (a), where the resist film (2) on the metal plate (1) should be partially removed, as shown in FIG. 1 (b), it is thin on the metal surface to be exposed. A so-called "drip" (t) that remains and is poor in resist cutting occurs. As a result, unevenness in etching occurs and the quality of the drilled hole deteriorates. Further, although the adhesion to the metal plate is very good, the resist film is likely to remain on a part of the resist film even when sprayed with a high temperature alkaline solution at a high pressure when the resist film is peeled off after etching, which causes rust on the metal plate. . Further, a method of mechanically scraping off the resist film in order to completely peel it off can be considered, but it is not preferable because it has a drawback that the metal plate is easily scratched.

In the case of the corrosion-resistant photosensitive film (1), it is necessary to form a thick resist film because the adhesiveness to the metal plate and the corrosion resistance, that is, the etching liquid resistance are inferior to those of the photosensitive film (1). As a result, when the contact pattern is baked by using a mask pattern, the thickness of the film becomes thicker, and the boundary between the soluble portion and the insoluble portion of the resist film becomes unclear, resulting in poor resist cutting and lowering the etching quality. Further, as shown in FIG. 2, the viscosity changes drastically with respect to the concentration, so that there is a drawback that it is very difficult to adjust the viscosity to obtain a target film thickness.
Incidentally, FIG. 2 shows the viscosity on the vertical axis against the solid content (%) of casein on the horizontal axis in centipoise (CP). The measurement temperature was 25 ° C., measured using a BL type rotational viscometer. is there.

In the case of the next corrosion-resistant photosensitive film, since it is a natural product, a difference in viscosity is likely to occur between the lots due to different raw materials used or the degree of hydrolysis. For this reason, it is difficult to obtain a desired resist film thickness under constant conditions, and there are drawbacks such as large variations in sensitivity.

Object of the invention The present invention is a corrosion-resistant film that can be easily formed to a predetermined film thickness, without cracking or floating during etching, and can be easily peeled off after etching without leaving a residue. It is an object of the present invention to obtain a corrosion-resistant photosensitive film capable of forming a high-quality etching pattern in which rust is unlikely to occur.

SUMMARY OF THE INVENTION The present invention is a mixture of a polyvinyl alcohol excellent in adhesion to a metal plate and having excellent etching liquid resistance and an acid casein solution which is easily cut off in a resist during development and is easily peeled off after etching. A photosensitive resist prepared by adding alkali dichromate and water to a solution is applied to a metal plate and dried,
It is a corrosion-resistant photosensitive film which is formed into a corrosion-resistant film having a predetermined film thickness by exposure, development and heating.

Examples of the Invention Hereinafter, examples of the present invention will be described in detail.

In the case where the anticorrosion photosensitive film of the present invention is applied to the production of a shadow mask for a color picture tube, the entire production method will be described first.

As shown in FIGS. 3 (a) to 3 (e), a smooth aluminum-killed low-carbon steel sheet having a thickness of 0.13 mm as a sheer mask material.
Using (1), degreasing and water washing are performed to remove oil and dirt during cold rolling. After that, both main surfaces of the mask material are covered with one of the photosensitive resists of the present invention, and the resist films (2) and (3) are formed by passing through a drying oven at about 60 to 100 ° C. (see FIG. 3 ( a)). The resist films (2) and (3) are preferably 3 to 10 .mu.m, though they differ depending on the mask material plate thickness used. Then, as shown in FIG. 3 (b), a negative image (4) having a small diameter, for example, a negative original plate (6) having a circular image of 0.06 mm on one main surface of the mask material (1) is attached to the other main surface. A large negative image (5) on the surface,
For example, negative masters (7) having a circular image of 0.19 mm are arranged in close contact with each other, and exposed using a light ray (10) such as ultraviolet rays. Next, the unexposed and uncured parts (8) and (9) of the resist films (2) and (3) are removed.
It is dissolved and removed by spraying hot water at 40 ° C to expose the metal surface (11) corresponding to the small hole forming portion and the metal surface (12) corresponding to the large hole forming portion on both main surfaces of the mask material (Fig. 3 (c)). . After that, the corrosion resistance of the residual resist film and the adhesion with the mask material are improved, and the desired corrosion-resistant film is subjected to a high-temperature heat treatment at 150 to 200 ° C. to prevent decomposition by an etching solution and peeling. , (14). Then, as shown in FIG. 3 (d), an etching liquid (15) such as ferric chloride (for example, a specific gravity of 1.46) is used.
5 ~ 1.470 liquid temperature 65 ~ 70 ℃) 1.0 ~ from both main surfaces of the mask material
The target opening portion (16) is formed by spraying at a pressure of 2.0 kg / cm ² . After the etching is completed, the residual etching solution is rinsed completely with water, and caustic soda solution of about 70 to 90 ° C is sprayed from both sides of the mask to remove the corrosion resistant films (13) and (14). Figure 3 (e)). Then, by washing with water and drying, a mask having a large number of desired holes is obtained.

Next, the corrosion-resistant photosensitive film applied to the above manufacturing will be described. The acid casein solution is a solution obtained by decomposing acid casein obtained from milk into water and adding sodium borate and heating and dissolving the solution, for example, Fuji Pharmaceutical TS-5 or Tokyo Ohka G-90. The stock solution has the following properties:

Polyvinyl alcohol is PVH manufactured by Union Chemical Co.
A modified polyvinyl alcohol in which a part of the groups was substituted with formalin or Gohsenol GL-05 manufactured by Nippon Synthetic Chemical Industry Co., Ltd. was used.

The composition obtained by adding ammonium dichromate as an alkali dichromate is as follows.

Water is added to the above composition ratio so that the viscosity and the specific gravity are adjusted to a predetermined value. In the case of the above test example, it is as follows.

It is desirable to use polyvinyl alcohol by adding polyvinyl alcohol powder with stirring to a reactor containing pure water so that it becomes a solution of about 10%, and then stirring it at a temperature of about 90 ° C and dissolving it. . The addition amount of polyvinyl alcohol as a photosensitive resist is about 5% to 30% of the solid content of the acid casein solution, and the chemical property is that the saponification degree is 80% from the viewpoint of heat fog during drying and the strength of the formed film.
It is suitable that the degree of polymerization is 90% and the degree of polymerization is 500 to 700. The amount of polyvinyl alcohol added may be about 50% of the acid casein solution solid content depending on the degree of polymerization. Furthermore, among sodium dichromate, potassium dichromate, ammonium dichromate, etc., as the alkali dichromate, ammonium dichromate is preferable in view of the photosensitivity of the formed film, but when used, it is dissolved in pure water. A solution of about 10% is suitable.

To apply the above-mentioned photosensitive resist film to the sheer mask, as shown in FIG. 4, the thin metal sheet (1) for the sheer mask is pulled up vertically through the immersion bath with rubber wiper (17) and passed through the drying oven (18). The drying furnace (18) is equipped with a sheath heater or infrastein heater and the surface temperature of the shed mask material is 90
The ambient temperature can be adjusted to a target value of ℃ or less. In the case of Test Example 1 above, the film thickness is 4.5 μm 5.5 μ
In the case of Test Example 2, a film thickness of 8 μm to 9 μm was suitable, but the pulling speeds at this time were 2 m / min and 0.7 m, respectively.
I'm doing it in minutes. However, since the pulling rate depends on the length of the drying furnace and the ambient temperature, it should be appropriately selected as the best condition.

Although the above-described embodiments have been described with reference to the examples applied to the sheer mask for a color picture tube, it goes without saying that the present invention can also be applied to the etching of other metal plates.

EFFECTS OF THE INVENTION According to the present invention as described above, as compared with the conventional one mainly containing alkali caseinate and alkali dichromate, the adhesion to a metal plate is excellent, the film strength is excellent, and the corrosion resistance during etching is high. The photosensitive photosensitive film is not peeled or cracked, and the remaining corrosion-resistant photosensitive film at the end of etching can be easily and completely removed. As a result, a high quality product with no etching pattern defects can be stably obtained. be able to.

[Brief description of drawings]

1 (a) and 1 (b) are schematic diagrams for explaining pattern formation of a corrosion-resistant photosensitive film, and FIG. 2 is a characteristic diagram showing the relationship between the solid content and viscosity of conventional casein, and FIG. (A) to (e) are manufacturing process diagrams for explaining an embodiment of the present invention, and FIG. 4 is a schematic diagram showing a photosensitive resist film coating apparatus. (1) …… Metal plate, (2), (3) …… Resist film (13), (14) …… Corrosion resistant photosensitive film

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP 54-138090 (JP, A) JP 54-138091 (JP, A) JP 47-12641 (JP, B1) JP 48- 43250 (JP, B1) JP 54-29297 (JP, B2)

Claims (2)

[Claims] 1. A corrosion-resistant photosensitive film used for etching a metal plate by a light exposure method, which has a saponification degree with an acid casein solution.
A corrosion-resistant photosensitive film comprising 80% to 90% of polyvinyl alcohol having a degree of polymerization of 500 to 700, an alkali dichromate photosensitizer and water. 2. The corrosion-resistant photosensitive film according to claim 1, wherein the alkali dichromate is ammonium dichromate.