Patent ID: 8541695

Claim:
A wiring board, comprising: a substrate having a first surface and a second surface on an opposite side of the first surface, the substrate having a first penetrating hole penetrating through the substrate between the first surface and the second surface, a first through-hole conductor formed on an inner wall of the first penetrating hole, a filler filled inside the first through-hole conductor and forming a second penetrating hole, and a second through-hole conductor formed in the second penetrating hole; a first conductive circuit formed on the first surface of the substrate and comprising a metal foil layer laminated on the first surface of the substrate; a second conductive circuit formed on the second surface of the substrate and comprising a metal foil layer laminated on the second surface of the substrate; a first conductive portion formed on one end of the second penetrating hole; and a second conductive portion formed on an opposite end of the second penetrating hole, wherein the first through-hole conductor is connecting the first conductive circuit and the second conductive circuit, the second through-hole conductor comprises a conductive material filled in the second penetrating hole and is connecting the first conductive portion and the second conductive portion, the first and second conductive portions integrally include the conductive material of the second penetrating hole, the first conductive circuit has a protruding portion protruding from a periphery portion of the first penetrating hole toward the second penetrating hole, and the first conductive circuit has a thickness which is greater than a thickness of the protruding portion of the first conductive circuit and a thickness of the first conductive portion.