JPS6349207B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an improved etching method for metal plates, and in particular provides an etching method suitable for use in manufacturing stamping dies used for manufacturing printed wiring boards by die stamping. . 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 slightly wider than the desired wiring circuit pattern and a circuit pattern positive film 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 to produce a stamping die having a blade shape with steps. A part of the manufacturing process of a stamping die using a conventional method will be briefly 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 in a plan view and in FIG. 2 as a cross-sectional view,
As shown in the sectional view in FIG. 3, an etching resist 2 is formed on the metal original plate 3, and the metal original plate 3 is etched to produce a metal original plate 5 having protrusions 4 as shown in FIG. Next, etching resist 2
is removed, the top of the protrusion 4 is polished, and the fifth
A metal original plate 8 having a flat protruding circuit portion 7 shown in the figure is obtained. 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, the plan view is shown in Fig. 6, and the plan view is shown in Fig. 7.
An etching resist 10 is formed as shown in FIG. 8 using a positive film B having a circuit pattern 9 slightly narrower than the desired wiring circuit pattern as shown in the cross-sectional view. The recess 13 is etched shallowly again using the etching method as shown in FIG.
After providing the acid-resistant resin 11, the acid-resistant resin 11 is heated and softened to be 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 and KTFR manufactured by Eastman Kodak, AZ-111 manufactured by Zipley, 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 surface are removed by alkaline degreasing, the surface is roughened by chemical polishing, and the surface is treated by neutralization and washing with water. After that, water-soluble photoresist ( Tokyo Ohka Kogyo 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 80-100rpm, 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 by improving the water-soluble photoresist and using it as a water-soluble photoresist containing a volatile rust inhibitor, the problems of the water-soluble photoresist can be solved. The present invention provides an etching method that solves these problems and also solves the workability and environmental problems associated with organic solvent-based photoresists, making it 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. For the metal base plate 3 shown in Figure 3, alloy tool steel SKS3 (manufactured by Hitachi Steel) is taken out as a plate material from the beginning, and the black scale is cut, annealed, and 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, a water-soluble photoresist containing the volatile rust preventive agent of the present invention is applied using a rotary coater, prebaked, and then exposed using negative film A (Figures 1 and 2). It is developed with water and post-baked to form an etching resist 2 (FIG. 3). Thereafter, a first etching process is performed to form the protrusion 4 shown in FIG. Etching is
The process is carried out using a paddle-type corrosive machine using a 45° Be' ferric chloride solution at a liquid temperature of 27°C to 31°C and a paddle rotation speed of 500 per minute. The depth of the recessed part 6 (Figs. 4 and 5) is 300 to 700 μm depending on the type and thickness of the metal foil to be cut.
Determine within the range of m. By removing the etching resist 2 shown in FIG. 4 and polishing the surface, a metal original plate 8 having a flat protruding circuit portion 7 shown in FIG. 5 is obtained.
As shown in FIG.
1 is filled with epoxy resin material, and as in the case of Fig. 3, a water-soluble photoresist containing the volatile rust preventive agent of the present invention is applied, and a positive film B (Fig. 6,
After exposure using a method (FIG. 7), development is performed with water, post-baking is performed, and a second etching process is performed to form the concave 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, etching resist 10
If the epoxy resin filled in the concave portion 11 is removed by heating and softening, a stamping die 12 having a blade-shaped protruding circuit portion 15 as shown in FIG. 10 is obtained.
is obtained. As shown in the above example, when the water-soluble photoresist containing the volatile rust inhibitor of the present invention is used, when the water-soluble photoresist is applied to the surface of the steel material and dried, as shown in the conventional example, This can solve the problem that fine rust occurs on the metal surface, making it impossible to form an etching resist pattern and making it impossible to etch a desired pattern. Note that the water-soluble photoresist used in the present invention includes, for example, a water-soluble azide compound,
4,4'-Diazidostilbene-2,2'-disulfonic acid 4-Azidobenzalmesityloxide-2-sulfonic acid 4-azidobenzalacetone-2-sulfonic acid

Water-soluble polymers copolymerized with acrylamide and other acrylic monomers, as well as polyvinylpyrrolidone and water-soluble cellulose, are used as resins to be blended with these water-soluble aromatic azide compounds using salts such as [Formula]. This is a water-soluble photoresist containing 0.1 to 4.0% by weight of a volatile rust inhibitor dicyclohexylammonium nitrite (C ₆ H ₁₁ ) ₂ NH ₂ NO ₂ in a photosensitive solution using a photosensitive solution such as the following. In addition, the volatile rust preventive agent used in the present invention means that the rust preventive agent itself gasifies (sublimates) like naphthalene and adsorbs to the metal surface to form a thin film.
This film prevents rust even in the presence of water and oxygen, and in addition to dicyclohexylammonium nitrite shown in the examples, there are diisopropylammonium nitrite, cyclohexylammonium carbonate, and the like. Also,
The appropriate concentration of the vaporized rust preventive agent in the water-soluble photoresist is 0.1 to 4.0% by weight; less than 0.1% by weight will cause rust, and if it exceeds 4.0% by weight, it will become saturated and will not dissolve completely, making the photoresist Cannot be used as a resist. 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 great 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 printed wiring boards 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, respectively, and FIGS. 8, 9, and 10 are the etched metal plate of FIG. 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 surface-treating a metal original plate made of steel material, a water-soluble photoresist containing a volatile rust preventive agent is applied to the metal original plate, dried, and then treated with the water-soluble photoresist. An etching method characterized in that after forming a desired pattern on the surface of the metal original plate, the metal original plate is etched. 2. The etching method according to claim 1, characterized in that a water-soluble photoresist containing 0.1 to 4.0% by weight of a volatile rust preventive agent is used.