Patent ID: 7564129

Claim:
A power semiconductor module comprising: a plurality of power semiconductor elements; a plurality of insulated substrates having the power semiconductor elements soldered on their top surfaces; a planar base plate having bottom surfaces of the insulated substrates soldered on its top surface; a plurality of radiation fins projecting from an area on a bottom surface side of the base plate, the area being on the opposite side to a junction area between the insulated substrates and the base plate; and a peripheral wall projecting from the bottom surface side of the base plate so as to surround the radiation fins, wherein the base plate, the radiation fins, and the peripheral wall are integrally formed to constitute a finned base plate, wherein the radiation fins are disposed along a flowing direction of a cooling medium, wherein a projecting length of the radiation fins is less than or equal to that of the peripheral wall, wherein the peripheral wall has end surfaces present in the same plane, and wherein the finned base plate is an aluminum-silicon carbide composite material having a linear expansion coefficient of 3 to 10 ppm/° C.