JPS6349208B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved etching method for metal plates, and in particular to an etching method suitable for use in manufacturing stamping dies used to manufacture printed wiring boards by die stamping. It provides:

Method 1 of manufacturing stamping die for printed wiring board
One of the well-known methods is the etching method. In this method, methods for manufacturing a stamping die having a blade shape suitable for punching circuit patterns from metal foil onto an organic insulating substrate are disclosed, for example, in Japanese Patent Publication No. 50-32651 and Japanese Patent Application Laid-Open No. 1983-1999.
There are methods described in Publication No. 1864, Japanese Patent Application Laid-Open No. 51-32959, etc. In the methods described in these publications, a circuit pattern negative film that is slightly wider than the desired wiring circuit pattern and a circuit pattern positive film that is slightly narrower than the desired wiring circuit pattern are created as a circuit pattern photomask used for forming an etching resist. Etching is performed twice using a circuit pattern photomask, and a stamping die having a blade shape with steps is manufactured.

A part of the manufacturing process of a stamping die using a conventional method will be explained using FIGS. 1 to 10.
Using a negative film A having a circuit pattern 1 slightly wider than the desired wiring circuit pattern, as shown in FIG. 1 as a plan view and as a cross-sectional view in FIG. 2, as shown in FIG. An etching resist 2 is formed on the original plate 3, and the original metal plate 3 is etched to form an original metal plate 5 having protrusions 4 as shown in FIG. Next, the etching resist 2 is removed and the surface of the upper part of the protrusion 4 is polished to obtain a metal original plate 8 having a flat protrusion circuit part 7 shown in FIG.
The concave portion 6 of this metal original plate 8 is filled with an acid-resistant resin 11 made of, for example, epoxy resin, as shown in FIG. Next, a positive film B having a circuit pattern 9 slightly narrower than the desired wiring circuit pattern as shown in FIG. 6 in a plan view and in FIG. 7 as a cross-sectional view is shown.
An etching resist 10 is formed as shown in FIG. After shallow etching is performed again using the etching method to form a recess 13 as shown in FIG. 9, the acid-resistant resin 11 is heated and softened and removed.
In this way, a stamping die 12 consisting of a blade protruding circuit portion 15 having a blade 14 as shown in FIG. 10 is manufactured.

In manufacturing the mold seen in this conventional example, the etching resist used in the etching process is as follows:
Organic solvent-based photoresists (for example, product names such as TPR manufactured by Tokyo Ohka Kogyo, FPER manufactured by Fuji Pharmaceutical, KPR, KTFR manufactured by Eastman Kodatsu, AZ-111 manufactured by Shipley, etc.) or water-soluble photoresists (trade names such as G-90, Nonchron, Fuji Pharmaceutical Co., Ltd. FR-14, 15, FCR-7, Yoshitani Shokai Aquaresist #100, etc.) were used.

However, when using these as etching resists for steel materials and manufacturing stamping dies by etching with ferric chloride solution, the use of organic solvent-based photoresists may result in poor workability (risk of fire due to organic solvents). There were environmental problems (odor and toxicity caused by organic solvents). On the other hand, using a water-soluble photoresist improves workability and environmental issues, but when etching steel materials, surface treatment before applying the water-soluble photoresist is extremely important, and surface treatment must be done properly. If this is not done, a water-soluble photoresist will be applied to the surface of the steel material, and when it dries, small metal rust will occur, making it difficult to perform the desired etching.

For example, steel materials (carbon tool steel SK3, machine structural carbon steel S45C, S55C, alloy tool steel SKD11, SKS3, etc.)
The oil and dirt adhering to the film are removed by alkaline degreasing, the surface is roughened by chemical polishing, and the surface is treated with neutralization and water washing processes. Industrial G-
90, Nonkron, Fuji Pharmaceutical FR-14, FR-
15, FCR-7, Yoshitani Shokai Aquaresist #100, etc.) is de-foamed, applied with water using a rotary coating machine at 80 to 100 rpm, and when it dries, fine rust appears on the metal surface, forming the desired pattern. There is a drawback that a stamping die having a blade type cannot be manufactured.

The present invention has been made in order to eliminate the drawbacks of the above-mentioned conventional examples, and provides a method for etching a metal original plate made of steel without using an organic solvent-based photoresist that has problems in workability and environment. It is. That is, the etching method of the present invention is characterized in that after surface-treating a metal original plate, the surface is wetted with an aqueous solution containing a volatile rust preventive agent, and then a water-soluble photoresist is applied. By adopting this method, the problems of water-soluble photoresists caused by conventional etching methods can be solved, and it becomes possible to manufacture stamping dies with excellent workability, environment, and productivity.

Hereinafter, an embodiment in which the etching method of the present invention is applied to manufacturing the stamping die described in the conventional example will be described with reference to the drawings.

Since the manufacturing process shown in FIGS. 1 to 10 can be applied to the present invention, one embodiment of the present invention will be described below according to this process. The metal base plate 3 shown in Fig. 3 is made of alloy tool steel SKS3 (manufactured by Hitachi Steel), which is taken out as a plate material from the beginning, and the black scale is cut off, annealed, and then vacuum quenched to HRC50°.
After the hardness is set to 60°, surface grinding is performed to form the desired shape. Next, this surface ground metal original plate 3
A paste made by adding water and a small amount of aqueous ammonia to precipitated calcium carbonate is applied and polished, then washed with water and air-dried. next,
0.1-4.0% _by weight volatile rust inhibitor _{dicyclohexylammonium} nitrite ( _{C6H11 ) 2NH2NO2}
The metal original plate 3 is wetted with the aqueous solution of the present invention containing the following: and then a conventional water-soluble photoresist (for example, FCR-7, FR-14, FR-15 manufactured by Fuji Pharmaceutical Co., Ltd., G-90 manufactured by Tokyo Ohka Kogyo Co., Ltd., Nonchron, etc. ) was coated with a rotary coater, pre-baked, exposed using negative film A (Figures 1 and 2), developed with water, and post-baked to form etching resist 2 (Figure 3). form. After that, a first etching process is performed to form the protrusion 4 shown in FIG.
make. Etching is carried out using a ferric chloride solution of 45 DEG Be' at a temperature of 27 DEG C. to 31 DEG C. using a paddle type etching machine with a paddle rotation speed of 500 per minute. Concave portion 6 (Fig. 4,
The depth of FIG. 5) is determined in the range of 300 to 700 μm depending on the type and thickness of the metal foil to be cut. Fourth
If the etching resist 2 shown in the figure is removed, a metal original plate 8 having a flat protruding circuit portion 7 shown in FIG. 5 is obtained. After filling this concave portion 6 with an epoxy resin material as an acid-resistant resin 11 as shown in FIG. 8, this surface is treated in the same manner as in the case of FIG.
After wetting the surface with the aqueous solution of the present invention containing 0.1 to 4.0% by weight of the volatile rust inhibitor dicyclohexylammonium nitrite, a conventional water-soluble photoresist was applied to form a positive film B (Figures 6 and 7).
Use and expose. Thereafter, the film is developed with water, post-baked, and then subjected to a second etching process to form the recessed portion 13 shown in FIG. Etching is performed under the same conditions as the first time, and the depth of the recessed portion 13 is determined in the range of 50 to 200 μm depending on the purpose. Next, the etching resist 10 is peeled off, and the epoxy resin filled in the concave portion 11 is heated and softened to be removed, thereby obtaining a stamping die 12 having a blade-shaped protruding circuit portion 15 as shown in FIG. 10.

As shown in the above example, if the metal surface is wetted with an aqueous solution containing the volatile rust preventive of the present invention and then a water-soluble photoresist is applied, the water-soluble photoresist can be applied to the steel material as shown in the conventional example. When applied to the surface and dried, fine rust occurs on the metal surface, making it impossible to form an etching resist pattern.
The problem that it is impossible to etch a desired pattern can be solved.

In addition, there are various types of rust preventive agents such as imidazole type rust preventive agents, but in the present invention,
The rust inhibitor itself gasifies (sublimates) like naphthalene and adsorbs to the metal surface to form a thin film.This film creates a volatile rust inhibitor that does not cause rust even in the presence of water or oxygen. In addition to dicyclohexyl ammonium nitrite shown in the examples, such volatile rust inhibitors include:
Examples include diisopropylammonium nitrite and cyclohexylammonium carbonate.

In addition, the appropriate concentration of an aqueous solution containing a volatile rust preventive agent is 0.1 to 4.0% by weight; less than 0.1% by weight will cause rust, and more than 4.0% by weight will become saturated and become completely insoluble in water. , when a water-soluble photoresist is applied, it remains as a foreign substance, making it impossible to form a pattern.

As explained above, according to the etching method of the present invention, workability (risk of fire due to organic solvent) and environment (odor due to organic solvent,
This solves the problem of ``hazardousness'' and the inability to form an etching resist due to rust on the metal surface when water-soluble photoresists are used.Furthermore, the surface of the manufactured metal plate is finished very cleanly, resulting in high quality The effect is extremely large when producing high-quality stamping dies for printed wiring boards.

[Brief explanation of the drawing]

The drawings are diagrams for explaining each process of manufacturing a stamping die for a printed wiring board using a photomask. Of these, Figures 1 and 2 each have a circuit pattern slightly wider than the desired wiring circuit pattern. A plan view and a cross-sectional view of the negative film; FIGS. 3, 4, and 5 are cross-sectional views for explaining the procedure for obtaining the circuit pattern of the negative film shown in FIG. 1 on a metal original plate by etching; FIG. , FIG. 7 is a plan view and a cross-sectional view of a positive film having a circuit pattern slightly narrower than the desired wiring circuit pattern, and FIGS. FIG. 2 is a cross-sectional view for explaining a procedure for manufacturing a stamping die having a blade-shaped circuit pattern. 2, 10... Etching resist, 3, 5, 8...
Metal original plate, 4... Protrusion part, 7... Flat protrusion circuit part, 1
1... Acid-resistant resin, 12... Stamping die, 14
...blade type, 15...blade type protruding circuit section.

Claims (1)

[Scope of Claims] 1. After wetting the surface of a metal base plate made of steel with an aqueous solution containing a volatile rust preventive agent, a water-soluble photoresist is applied to the metal base plate and dried, and then the water-soluble photoresist is coated with the water-soluble photoresist. Therefore, the etching method is characterized in that after forming a desired pattern on the surface of the metal original plate, the metal original plate is etched. 2. In the statement of claim 1, the volatile rust inhibitor is contained in an aqueous solution of 0.1% to 4.0% by weight.
An etching method characterized by using a material containing