Semiconductor device and manufacturing method thereof

A semiconductor device having high reliability and excellent heat radiation and a method for manufacturing the device at low coat. A semiconductor element and a cover as a heat radiation member are bonded through a solder-containing carbon member having a structure that outside solder layers are formed on a surface of a solder-containing carbon sintered body formed by impregnating a carbon sintered body with solder. By using the sintered body for a junction between the semiconductor element and the cover, thermal stress during heat generation in the semiconductor element can be relieved while securing high heat radiation. By impregnating the sintered body with inexpensive solder, the sintered body and the outside solder layers can be tightly bonded. Through the outside solder layers, the semiconductor element and the cover can be tightly bonded. Thus, the semiconductor device having high reliability and excellent heat radiation can be realized at low cost.