Patent ID: 7597929

Claim:
A method of manufacturing a wiring substrate, comprising the steps of: preparing a laminated body having such a structure that a peelable metal foil in which a lower metal foil and an upper metal foil are laminated peelably and an opening portion is provided on a peripheral side is pasted onto a supporting body; forming a through hole having a diameter smaller than the opening portion by processing a portion of the supporting body on an inner side of the opening portion to obtain a reference hole having a projection portion in an inside; forming a resin layer on the peelable metal foil and the projection portion in the reference hole to cover a side surface of the opening portion, and then forming a build-up wiring constructed to contain the resin layer; removing portions of the build-up wiring and the laminated body corresponding to an area containing the opening portion to expose a peeling boundary of the peelable metal foil; peeling the upper metal foil from the lower metal foil at the peeling boundary to separate the upper metal foil and the build-up wiring from the supporting body side; and removing the upper metal foil from the build-up wiring.