JPH05206610A - Manufacture of printed wiring board - Google Patents

Abstract

PURPOSE:To prevent the deposition of defective film and form a uniform film in electrodeposition of resist on a printed wiring board by a constant current method by changing the current density when in the state of a minute and/or thin film. CONSTITUTION:In electrodeposition of resist on a printed wiring board by a constant current method, the current density is changed when in the state of a minute and/or thin film. The printed wiring board may use such resins as epoxy, phenol, unsaturated polyester and silicone. For example, the surface of a glass cloth based epoxy resin laminate is subjected to a resist electrodeposition on a current of 55mA/dm<2> for 30sec for the first and second stages and for 115sec for the third. Since a minute and/or thin film is to be formed in the second stage, the current density is reduced therein. This eliminates the deposition of defective electrodeposition films, obtaining uniform films.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a printed wiring board used in electric equipment, electronic equipment, communication equipment, computing equipment, etc. by an electrodeposition method.

[0002]

2. Description of the Related Art A conventional method for producing a printed wiring board by electrodeposition is a constant current method in which a resist is electrodeposited on a substrate in a constant current region. Therefore, there is a problem that a thin film, a minute film, a film formation and a film formation progress, so that an unreasonable phenomenon occurs at a portion where the film is formed and an abnormal film is easily deposited.

[0003]

As described in the prior art, the conventional method for producing a printed wiring board by the electrodeposition method has a drawback that a uniform electrodeposition film cannot be obtained. The present invention has been made in view of the above problems in the prior art, and an object thereof is to provide a method for manufacturing a printed wiring board by an electrodeposition method capable of obtaining a uniform electrodeposition film.

[0004]

SUMMARY OF THE INVENTION The present invention relates to a printed wiring board characterized in that the current density in a fine film and / or thin film state is made variable during constant-current resist electrodeposition on the printed wiring board. The manufacturing method has achieved the above object, and the present invention will be described in detail below.

The printed wiring board used in the present invention includes epoxy resin, phenol resin, unsaturated polyester resin, silicone resin, polyphenylene sulfide resin, polyethylene terephthalate resin, polybutylene terephthalate resin, and polyimide as the resin. Resin type, polybutadiene resin type, fluorine resin type, etc.
All resins such as modified products and mixtures can be used,
If necessary, an inorganic powder filler such as talc, clay, silica, calcium carbonate, and aluminum hydroxide, or a fibrous filler such as glass fiber, asbestos fiber, pulp fiber, synthetic fiber, and ceramic fiber can be contained. .. As the base material, use inorganic fibers such as glass and asbestos, organic fibers such as polyester, polyamide, polyacryl, polyvinyl alcohol, polyimide and fluororesin, woven fabrics of natural fibers such as cotton, non-woven fabrics, mats and papers. You can As the resist, a commonly used electrodeposition resist can be used as it is without any particular limitation. Resist electrodeposition is constant current method resist electrodeposition, but the current density in the state of micro film and / or thin film is checked by a timer and applied voltage and variably adjusted to prevent the occurrence of abnormal film, and uniform electrodeposition film. Can be formed on a printed wiring board.

The present invention will be described below based on examples.

[0007]

EXAMPLE An electrodeposition resist was applied on the surface of a glass cloth substrate epoxy resin laminate having a thickness of 1 mm at a current value of 55 mA / dm ² .
Processing is performed in the first step 30 seconds, the second step 30 seconds, and the third step 115 seconds, but since the film formation in the second step becomes a fine film and / or a thin film state, the current density in the second step should be reduced. As a result, a uniform electrodeposition film could be obtained.

[0008]

[Comparative Example] A printed wiring board was obtained in the same manner as in Example except that the current density was kept constant without lowering the current density in the second step.

The performance of the printed wiring boards of Examples and Comparative Examples is as shown in Table 1.

The present invention is constructed as described above.
In the method for manufacturing a printed wiring board having the structure described in the claims, there is an effect that a uniform electrodeposition film can be obtained without abnormal deposition of the electrodeposition film.

Claims (1)

[Claims] 1. A constant current method resist electrodeposition on a printed wiring board, the current density in the state of a fine film and or thin film,
A method for manufacturing a printed wiring board, which is variable.