Patent ID: 7174632

Claim:
A method for manufacturing a double-sided circuit board, comprising: providing a through hole in a laminate in which mold release films are formed on both surfaces of a circuit board electrically insulating material that is a circuit board electrically insulating sheet comprising a porous sheet in which a resin layer is laminated to at least one surface of the porous sheet and at least a portion of the resin layer is not impregnated in pores that are present inside the porous sheet, and only a central portion of the porous sheet is not impregnated with resin from the laminated resin layer and the circuit board electrically insulating material has a sufficiently small thickness for use in a circuit board; filling the through hole with a conductive paste; peeling off the mold release film from the laminate in which the through hole is filled with the conductive paste; superimposing metal foils on both surfaces of the circuit board electrically insulating material from which the mold release films have been peeled off to form a laminate; heating and pressing the laminate to allow hollow pores of the porous sheet to be filled with resin and allow the metal foils to be adhered to the porous sheet, and compressing and hardening the conductive paste filled in the through hole, thereby providing an inner via hole; and forming desired circuit patterns on the metal foil.