Patent ID: 7781894
Filing Date: 2010-08-24
Classification: H01L

Abstract:
1. A semiconductor device comprising: a semiconductor substrate of a first general conductivity type having a piercing hole piercing the substrate from a front surface thereof to a back surface thereof; a source layer formed in the front surface of the substrate; a drain electrode disposed on the front surface of the substrate to cover the piercing hole; a metal film disposed on the back surface of the substrate so as to make a direct contact with the back surface of the substrate; and a drain wiring disposed inside the piercing hole and electrically connected with the drain electrode, the drain wiring covering the metal film, wherein the drain wiring comprises a wiring layer and a barrier metal film disposed between the wiring layer and a sidewall of the piercing hole, the barrier metal film covers the metal film, the wiring layer is physically in contact with the barrier metal film, the metal film is disposed on the back surface of the substrate so that the barrier metal film is not in contact with the back surface of the substrate, and part of the metal film is disposed between the drain electrode and the drain wiring so as to be physically in contact with the drain electrode.