Patent ID: 7813135

Claim:
A semiconductor device, comprising: a circuit board including an insulating substrate, a first metal plate fixed on a first side of the insulating substrate, and a second metal plate fixed on a second side of the insulating substrate; a semiconductor element mounted on the first metal plate; a stress reducing member brazed to the second metal plate by a first brazing filler metal, the stress reducing member being plate-shaped and having a plurality of round-shaped corners in planar view, wherein the stress reducing member has a substantially same plan shape and size as the second metal plate; and a heat cooling element brazed to the stress reducing member by a second brazing filler metal, wherein each of the round-shaped corners of the stress reducing member and each corresponding corner of the second metal plate and the heat cooling element form a step-structure together in the direction of the thickness of the circuit board, respectively with the result that a stress reducing space is formed by the second metal plate, the heat cooling element and the round-shaped corner.