Patent ID: 8063484

Claim:
A semiconductor device, comprising: a semiconductor element having a rectangular two-dimensional geometry and serving as a heat source; and a heat sink section having said semiconductor element mounted thereon, wherein a direction for exhibiting a smallest one of directional components of a thermal conductivity of said heat sink section in X, Y and Z directions is parallel to an X direction, where a longer side direction of said semiconductor element is defined as the X direction, a shorter side direction thereof is defined as a Y direction, and a thickness direction is defined as a Z direction, wherein a relation among the directional components of said thermal conductivity is: Kzz>3×Kxx and Kyy>3×Kxx, wherein the thermal conductivity of said heat sink section is defined as K, and directional components of a three-dimensional thermal conductivity of said heat sink section in the X, Y and Z directions are defined as Kxx, Kyy, and Kzz, respectively.