JPS6226889A - Manufacture of printed wiring 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 (-0 INDUSTRIAL APPLICATION FIELD) The present invention relates to the manufacture of printed wiring boards, and more particularly to a method of forming a conductor pattern on an insulating board.

(r: 4) Conventional technology In general, the conventional method of manufacturing printed wiring boards is to form a circuit on an insulating substrate laminated with copper foil by a method such as printing, and then remove the remaining circuit by etching, leaving only the effective circuit. The so-called etching method.

There is also a so-called additive method in which a circuit pattern is formed by activating an insulating substrate to promote adhesion and then printing and adhering a plating base.

All of these methods have advantages and disadvantages; the former etching method requires a large amount of copper foil to be removed and the processing of the etching solution is polluting, while the latter additive method requires larger manufacturing equipment. Furthermore, there was a problem in that the adhesive force between the conductor pattern and the substrate was weak.

In order to solve these problems, the %Koshō 59-223
A method as described in Japanese Patent No. 86 was proposed.

In other words, a laminate is created by depositing a conductive thin film such as copper on a hard insulating substrate, applying a thermoplastic resin paste on top of it, and attaching a cover resin film. Alternatively, a desired circuit pattern is drawn by irradiation with an appropriate ultraviolet radiation type light source, and the adhesiveness of the paste to the conductive thin film portion of the irradiated portion is eliminated.
The cover resin film is removed, the conductive thin film part other than the circuit pattern related to irradiation is peeled off, a thin conductive circuit pattern base is created on the substrate, and metal plating is applied to the base to a predetermined thickness. ``forming a conductive circuit pattern.''

e→ Problems to be solved by the invention When the above method is used, neither the etching method nor the additive method is used, and cleaning treatment is unnecessary, but a laser beam or a suitable ultraviolet radiation type light source is required. As a result, there was a problem in that the printed wiring board manufacturing equipment became complicated.

In view of these problems, the present invention provides a method for manufacturing printed wiring boards that does not require large-scale equipment and can be mass-produced at low cost.

2) Means for Solving the Problems In the method of manufacturing a printed wiring board according to the present invention, a circuit pattern is first formed on an insulating substrate using a thin metal film that has good adhesion to the substrate, and then a circuit pattern is formed on this pattern. A conductor is formed by coating the wire with solder.

(E) Effect: If a printed wiring board is manufactured using this method, the thickness of the metal circuit pattern can be made thick enough to be coated with solder, and the amount of metal conductors used can be reduced.

(F) Embodiments Hereinafter, embodiments of the present invention will be explained based on the drawings. First, FIG. 1 shows a circuit pattern (2) formed with a metal thin film on an insulating substrate (1). The material for this insulating substrate (1) is phenolic resin, polyimide resin, etc.
-1-Phoxy resin or a film thereof is used. Furthermore, a thin film of a metal that has good adhesion to the substrate (1), such as copper, nickel, silver, gold, palladium, etc., is applied onto this base (1tl) by printing, sputtering, or etching of an extremely thin substrate with a metal surface. Circuit pattern (
2) It is formed into a shape.

FIG. 2 is a diagram showing the state in which the insulating substrate (1) on which the pattern (2) is formed as shown in FIG. 1 is placed in a molten solder bath (3), and (4) is molten solder.

FIG. 3 is a completed diagram of the printed wiring board according to the present invention,
The insulating substrate (1) shown in FIG. 2 is taken out from the molten solder bath (3). (5) is a solder layer coated on the pattern (2), and the pattern (2) and this solder layer (5) form a conductor.

As described above, a printed wiring board can be obtained by sequentially performing the steps shown in FIG. 1, FIG. 2, and FIG. 3. A solder layer (5) is placed on this printed wiring board pattern (2).
), the solder adheres well when soldering parts, improving workability. At the same time, a sufficient conductive area can be obtained between the thickness of the pattern (2) and the thickness of the solder layer (5).

In addition, if the insulating substrate (1) is placed in the molten solder tank (3) with components placed on the pattern (2) of the insulating substrate (1), the pattern (2) will be coated with solder Jm+5+. (It is possible to simultaneously solder parts and improve work efficiency.

(G) Effects of the Invention The method for manufacturing a printed wiring board according to the present invention involves first forming a circuit pattern on an insulating substrate using a thin metal film that has good adhesion to the substrate, and then coating this pattern with solder. Since the conductor is formed using the same method, the pattern of the metal circuit formed on the insulating substrate can be made thinner. Furthermore, since the pattern is coated with solder, a sufficient conductive area can be ensured by matching the thickness of the metal pattern and the thickness of the solder coating, and at the same time, the solder adheres well when parts are mounted.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a circuit pattern formed on an insulating substrate, and FIG. 2 is a cross-sectional view of the insulating substrate shown in FIG. 1 placed in a molten solder bath. FIG. 3 is a cross-sectional view of a printed wiring board manufactured using the method. (1)...Insulating substrate, (2)...Pattern, (
3)... Molten solder tank, (4)... Molten solder, (
5)...Solder layer.

Claims (1)

[Claims] (1) A method for manufacturing a printed wiring board, which comprises forming a circuit pattern on an insulating substrate using a thin metal film that has good adhesion to the substrate, and coating the pattern with solder.