Patent ID: 7554191

Claim:
A semiconductor device comprising: a substrate; a semiconductor chip mounted on said substrate; and a heatsink plate covering said semiconductor chip and fixed to said substrate, said heatsink plate having a fixing surface and an opposite surface, the opposite surface facing opposite the fixing surface, wherein said heatsink plate includes at least one bored portion formed on the fixing surface configured to be fixed to said substrate via a resin provided in said bored portion, wherein said bored portion is a through hole communicating between said fixing surface to said substrate and to the opposite surface, wherein said resin in said bored portion includes i) a first portion provided in a gap between said upper surface of said substrate and said fixing surface, a diameter of said first portion being larger than a diameter of said through hole, ii) a second portion filled in said through hole, and iii) a third portion provided on said opposite surface, a diameter of said third portion being larger than the diameter of said through hole, and wherein a relationship of EB≦EA and EB≦EC is satisfied, EA, EB, and EC representing the elastic modulus, respectively, of said first portion, said second portion, and said third portion.