| 摘要 |
PROBLEM TO BE SOLVED: To enhance the reliability of a circuit board comprising three or more layers by forming an insulating layer on the wiring pattern on the surface of an insulating board, forming a plating layer on the bottom of openings formed in positions corresponding to through holes, roughing the surface of the insulating layer, thereafter etching a second plating layer formed on the insulating layer to form a second wiring pattern. SOLUTION: An insulating layer 10 is formed on a first wiring pattern 6 containing through holes 2 penetrating an insulating board 1, and openings 11 are formed to connect the front side and rear side of the insulating board 1. The surface of a copper paste layer on the bottom of the openings 11 is plated to form a plating layer 12. Then, the surface of the insulating layer 10 is roughed, and the roughed surface is plated to form a second copper plate layer 13. Thereafter, a resist pattern is formed on the surface of the plating layer 13, and etching is performed. Then, the etching resist is stripped to obtain a second wiring pattern 14 both on the front side and on the rear side of the insulating board 1. |
