Patent ID: 8169054

Claim:
A semiconductor device comprising: a semiconductor substrate having a first surface and a second surface opposite from the first surface; a first conductor disposed on the first surface of the semiconductor substrate; a second conductor disposed on the second surface of the semiconductor substrate; a via hole penetrating through the semiconductor substrate and connecting the first conductor and the second conductor; a barrier layer disposed in the via hole; and a penetrating electrode disposed on the barrier layer in the via hole so as to electrically connect the first and second conductors, wherein the barrier layer comprises a first conducting barrier layer formed on an inner sidewall of the via hole and a second conducting barrier layer formed at a bottom end of the via hole, the first conducting barrier layer comprises an upper wall portion and a lower wall portion that are disposed on the inner sidewall of the via hole, and the lower wall portion is thicker than the upper wall portion and located at the bottom end of the via hole, the bottom end of the via hole is located on the side of the first surface of the semiconductor substrate, the first and second conducting barrier layers are disposed on the second surface of the semiconductor substrate so that the first conducting barrier layer is between the second conducting barrier layer and the second surface of the semiconductor substrate, and the second conducting barrier layer is, at least partially, physically in contact with the first conductor such that the whole bottom end of the via hole is covered by the barrier layer.