Patent ID: 8324736

Claim:
A semiconductor device in which a first through silicon via of a first semiconductor chip having a semiconductor substrate and a second through silicon via of a second semiconductor chip having a semiconductor substrate are electrically connected to each other, the semiconductor device comprising: an interlayer insulating film formed on a first surface of the first semiconductor chip; a pad formed on the interlayer insulating film; and a bump electrode formed on the pad; wherein the first through silicon via reaches the pad from a second surface of the first semiconductor chip on a side opposite to the first surface, wherein the first through silicon via includes: a first hole which reaches the interlayer insulating film from the second surface of the first semiconductor chip on a side opposite to the first surface and whose bottom surface is formed at a position closer to the pad than to an interface between the interlayer insulating film and the semiconductor substrate; a second hole whose diameter is smaller than a diameter of the first hole and which is formed to reach the pad from the bottom surface of the first hole; an insulating film formed on bottom and side surfaces of the first hole and on the second surface of the semiconductor substrate; and a conductive film which is formed on bottom and side surfaces of the second hole, on the bottom and side surfaces of the first hole via the insulating film and on the second surface of the semiconductor substrate and is electrically connected to the pad, wherein the first through silicon via of the first semiconductor chip and the second through silicon via of the second semiconductor chip are electrically connected to each other through the bump electrode formed on an upper surface of the pad, wherein a surface of the interlayer insulating film on a side of the semiconductor substrate has a step shape reflecting a step difference between the bottom surface of the first hole and the first surface of the semiconductor substrate.