Patent ID: 8089004

Claim:
A semiconductor device comprising: an interposer; and a semiconductor chip mounted on the interposer, wherein, in a plan view, the interposer includes a first region overlapping the semiconductor chip, and a second region excluding the first region, and the interposer includes at least one wiring therein, the wiring being formed astride the first region and the second region, wherein a cross-sectional area of the wiring in the first region of the interposer is smaller than a cross-sectional area of the wiring in the second region of the interposer, wherein the semiconductor chip is mounted on the interposer via a mounting material, an upper surface of the semiconductor chip comprising a circuit and a pad, and wherein the wiring in the second region of the interposer and the pad on the semiconductor chip are electrically connected via a wire, wherein a characteristic impedance of the wiring in the first region is substantially equal to a characteristic impedance of the wiring in the second region.