Patent ID: 7350297

Claim:
A manufacturing method of a wiring substrate, comprising: printing a first plating foundation layer on a front face of a sheet-shaped insulating substrate; forming a through hole connecting between the front face and rear face of the sheet-shaped insulating substrate by inserting a punch into the sheet-shaped insulating substrate having the first plating foundation layer to generate a cut in the sheet-shaped insulating layer while leaving a piece of the sheet-shaped insulating layer having the plating foundation layer and separated from the sheet-shaped insulating substrate along the cut while a part of the sheet-shaped insulating layer is continued from the sheet-shaped insulating substrate in a portion where the punch is inserted; printing a second plating foundation layer on the rear face of the sheet-shaped insulating substrate; and performing electroless plating to the plating foundation layers to form first and second wiring layers respectively composed of a metal plating layer on the first and second plating foundation layers, and to form the metal plating layer connecting between the first and second wiring layers in the through hole using the plating foundation layer on both obverse and reverse of the piece.