Printed circuit board

摘要

The present invention provides a printed circuit board in which electrode layers can electrically be connected by an inner-through-hole connection, the coefficient of thermal expansion of the board is equal to that of a semiconductor, high thermal conductivity can be obtained and wiring can be formed at a high density. A cover film (25) is laminated on both surfaces of a resin impregnated fabric sheet (1), holes are formed by laser beams in the direction of the thickness of the sheet (1) and cover film (25), an electrically conductive paste (23) that contains the electrically conductive particles (3) and a thermosetting resin is filled in the holes. The cover film (25) is removed, a copper foil (22) is placed on both sides of the sheet (1), and pressed and heated, and the resin component of the sheet (1) and that of the electrically conductive paste (23) are hardened. The copper foil (22) is etched to form circuit patterns (6) and (26), and further etching removes the electrically conductive particles (3) present at a surface layer portion so that an electrical insulating layer (4) is thus formed.