Semiconductor device

1. A semiconductor device comprising:

a semiconductor element including an outer peripheral end face;

a heat sink including an inner face, an outer face and an outer peripheral end face, the semiconductor element being fixed to the inner face; and

a package covering the outer peripheral end face of the semiconductor element, the inner face of the heat sink except an area to which the semiconductor element is fixed, and the outer peripheral end face of the heat sink, wherein

the outer face of the heat sink is not covered by the package,

a recess portion is formed in an outer peripheral end face of the package,

the heat sink includes a thin area having a thin area outer face opposite the inner face of the heat sink, the thin area includes a thickness between the thin area outer face and the inner face of the heat sink that is smaller than a thickness between the outer face of the heat sink and the inner face of the heat sink of a part surrounding the thin area, the thin area is formed adjacent the outer peripheral end face of the heat sink and adjacent the outer peripheral end face of the package in which the recess area is formed, the thin area outer face is positioned on an inner side of the outer face of the heat sink in a thickness direction of the semiconductor device,

wherein the package is not formed on the thin area outer face of the thin area,

wherein a portion of the inner face of the heat sink opposite the thin area outer face contacts the package in the thin area.

2. The semiconductor device according to claim 1 , wherein in the thin area, the outer face of the heat sink is dented.

3. The semiconductor device according to claim 1 , wherein

the thin area is provided between the recess portion and the semiconductor element when the thin area is seen from a direction perpendicular to the inner face of the heat sink.

4. The semiconductor device according to claim 1 , wherein the package is not formed on a face of the thin portion opposite the first surface of the heat sink.

5. A semiconductor device comprising:

a semiconductor element;

a heat sink including a first surface and a second surface, the semiconductor element being joined to the first surface, the second surface being a surface on an opposite side of the first surface; and

a package that is in contact with the semiconductor element and the first surface of the heat sink, the package including a recess portion in an outer face, wherein

the heat sink includes a thick portion, and a thin portion having a thickness that is smaller than that of the thick portion,

the thin portion is located on a line connecting an outer face of the semiconductor element and the recess portion in a shortest distance, and

the thin portion is formed as a generally cylindrically shaped dent that extends from the second surface of the heat sink towards the first surface of the heat sink

wherein an entire surface of the heat sink which faces inside of the semiconductor device contacts the package in the thin portion.

6. The semiconductor device according to claim 5 , wherein the thin portion only extends partially through the heat sink from the second surface towards the first surface.

7. The semiconductor device according to claim 5 , wherein a part of the second surface of the heat sink is exposed from the package.

8. The semiconductor device according to claim 5 , wherein the package includes a resin.

9. The semiconductor device according to claim 5 , wherein the thin portion is surrounded by the thick portion.