Patent ID: 7813133

Claim:
A semiconductor device, comprising: a board; a semiconductor element mounted on one of main surfaces of the board; a plurality of passive elements provided in the vicinity of the semiconductor element; and a heat radiation plate mounted above the board and connected to a rear surface of the semiconductor element via a heat conductive material; wherein a concave shaped space part is formed at a side of the heat radiation plate facing the semiconductor element; a space part forming surface is formed at an upper surface of the concave shaped space part and includes a first surface and a second surface, the first surface is arranged in the center of the space part forming surface, and the second surface is an external side area of the first surface in the space part forming surface, and the second surface is external to a boundary of the semiconductor element; a surface roughness of the first surface of the space part forming surface of the concave shaped space part is smaller than a surface roughness of the second surface of the space part forming surface of the concave shaped space part, the first surface coming in contact with the heat conductive material, and a difference between the surface roughness of the first surface and the surface and the second surface is equal to or greater than 0.5 μm.