Patent ID: 8794499

Claim:
A method for manufacturing a substrate, comprising the steps of: forming a bump of a conductive paste containing metal fillers on a metal foil which is to be contact-bonded to a thermosetting insulating resin layer, the metal fillers having a melting temperature lower than a reflow temperature of the conductive paste and lower than a curing temperature of the insulating resin layer; heating the bump to a temperature lower than the curing temperature, at which the metal fillers are melted, to form the metal fillers bound to each other by melting, and to form a metallic bond between the bump and the metal foil, thereby integrally connecting a metal column of the bump to the metal foil; press-fitting the metal column into the insulating resin layer before being completely cured, thereby contact-bonding the metal foil to the insulating resin layer, and joining a tip of the metal column to an opposed metallic member; and subjecting the insulating resin layer to a heat treatment after the joining to reheat the metal column, thereby re-melting the metal fillers, and forming a metallic bond between the metal column and the metallic member to integrally connect the metal column to the metallic member; wherein in the step of subjecting the insulating resin layer to a heat treatment, the metallic bond between the metal column and the metallic member is formed by alloying through diffusion in a solid layer between the metal column and the metallic member.