Patent ID: 7222421

Claim:
A circuit substrate manufacturing method comprising the steps of: preparing a substrate on which a metallic foil is formed in a releasable state on at least one surface of the substrate, a peripheral portion of said metallic foil being selectively pasted on the substrate by an adhesive layer which is selectively arranged with a ring shape on a peripheral portion of the substrate or the metallic foil; forming an insulating film in which opening portions are provided on the metallic foil; forming first wiring patterns, which are electrically connected to the metallic foil via the opening portions, on the insulating film; obtaining a circuit member, which is constructed by the metallic foil, the insulating film, and the first wiring patterns, by cutting and removing an entire peripheral portion of the substrate containing the adhesive layer and then separating the metallic foil from the substrate; and forming second wiring patterns, which are connected electrically to the first wiring patterns via the opening portions in the insulating film, on an opposite surface of the insulating film to a surface, on which the first wiring patterns are formed, by patterning the metallic foil of the circuit member.