JPS59106181A - Method of producing printed circuit board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a printed wiring board.

Conventionally, various methods have been considered for manufacturing printed wiring boards. For example, after pasting a copper foil with a thickness of about 35 microns on an insulating substrate, an etching resist film is formed on a predetermined circuit portion, and then the copper foil except for the predetermined circuit portion is removed by etching. There is a method of forming a predetermined circuit by peeling off a resist film. This method requires removing the copper foil with a thickness of approximately 35 microns excluding the designated circuit portion by etching.
During this etching, a large amount of copper is wasted, and there is an extremely high risk that side etching will occur in the copper foil in the predetermined circuit area. It requires management.

In addition, there is a conventional method in which a predetermined circuit part is directly formed on an insulating substrate using the agate method, but in this method, the insulating substrate is coated with a stannous chloride solution and a very expensive palladium chloride solution using a high-precision chemical solution. An activation treatment step in which metal palladium is deposited on the surface of the insulating substrate by sequential immersion under controlled conditions, a step of forming a metal resist film on the insulating substrate excluding predetermined circuit portions, and a further step in which predetermined circuit portions are coated with chemical copper plating. Forming a copper plating layer] If a double culm is required and further warping of the copper plating layer is required, electrolytic copper plating is further applied to the surface of the copper plating layer and the copper plating layer is grown. I had to let it happen.

As described above, the conventional method requires complicated manufacturing processes, wastes metals such as copper, uses expensive chemicals such as palladium chloride, and requires a great deal of effort to manage the chemicals. was considered difficult. The present invention eliminates the shortcomings of these conventional methods, makes it possible to manufacture highly reliable printed wiring boards through a simple process, reduces wasted power consumption for copper and other metals, and improves chemical management without using expensive chemicals. It also provides a method of manufacturing at low cost by reducing the difficulty.

Hereinafter, the present invention will be explained based on the drawings.
3, 4, and 5 are explanatory diagrams showing the method for manufacturing a printed wiring board according to the present invention.

Figure 1 shows an insulating substrate (1) such as a glass Evokin resin plate whose surface has been roughened by sandblasting etc., a thin polyester resin film, or a polyimide resin film.
-L shows a state in which a copper thin film (2) is formed by vacuum evaporation, thin film or sputtering, and the insulating substrate (1
) The roughening process applied to the surface is for increasing the adhesion with the copper thin film (2).

FIG. 2 shows that after forming an alkali-soluble metskiresist coating (3) on the surface of the copper thin film (2) except for a predetermined circuit area by a printing method, a photographic method, or a transfer method,
It shows the dried and hardened state.

FIG. 3 shows a copper plating layer (4) formed on the predetermined circuit portion in an acidic copper plating bath.

The copper plating layer (4) in this step may be formed using either electrolytic copper plating or dimension chemical copper plating.

Figure 4 shows a state in which a metal plating layer (5) made of nickel, tin-lead alloy, tin-nickel alloy, etc., which is resistant to corrosion against alkaline etching liquid in an acidic plating bath, is formed on the predetermined circuit portion. ing. In this step as well, the metal plating layer (5) may be formed using any of the electroplating methods, plating methods, or chemical plating methods. The metal plating layer (5) thus formed acts as an etching resist film in the etching solution shown in FIG. There is.

Furthermore, FIG. 5 shows that the alkaline soluble metal oxide film (3) is etched with an alkaline etching solution such as an ammonia etching solution, and the copper thin film (
2) is removed, and a printed wiring board having the predetermined circuit portion is completed.

As described above, as shown in the explanatory diagram of FIG. 1, the method for manufacturing a printed wiring board according to the present invention uses a thin copper film formed by a vacuum evaporation method or a sputtering method.
Unlike conventional methods, formation of chemical copper plating nuclei using palladium chloride, which is expensive and difficult to control, is not required.Furthermore, the alkali-dissolved metsukire cyst coating (3) used in the present invention In addition to having a masking role when forming a copper plating layer (4) on a predetermined circuit portion and a masking role when forming a metal plating layer (5) on a predetermined circuit portion in FIG. When etching the thin copper film (2) other than the designated circuit portion in the figure,
Since it can be removed easily, there is no need for a peeling process after the etching process as in the conventional method, which simplifies the process. Moreover, the time required for etching is limited because the copper thin film (2) is formed by vacuum evaporation or sputtering.
The film thickness is extremely thin, so etching can be completed instantly.

Therefore, it has the advantage that higher productivity can be obtained compared to the conventional method.

As described above, the present invention is a method that is extremely useful in practice and has many benefits, as it enables the production of high-quality printed wiring boards in a short period of time in a relatively simple process without using chemicals that are expensive and require difficult management, unlike conventional methods. It has a certain effect.

[Brief explanation of drawings]

1 to 5 are explanatory diagrams showing the method of manufacturing a printed wiring board of the present invention. 1... Insulating substrate 2... Copper thin film 3... Alkali-dissolved metal resist coating 4... Copper plating layer 5... Metal plating layer Patent applicant Toyo Shigyo Co., Ltd. 391

Claims (1)

[Claims] After forming a copper thin film on an insulating substrate by vacuum evaporation and ox sputtering, an alkali-dissolved metal resist coating is formed on the surface of the copper thin film except for the predetermined circuit area, and then an acidic copper plating bath is used to form the copper thin film. After forming a copper plating layer on a predetermined circuit portion and further forming a metal plating layer that is resistant to corrosion with an alkaline etching solution on the surface of the copper plating layer, the alkali-dissolved metal-resist coating is removed using an alkaline etching solution. A method for manufacturing a printed wiring board, comprising removing the copper thin film except for the predetermined circuit portion.