Semiconductor device and method of manufacturing the same

A semiconductor device, comprising:

• a Zn alloy layer having a plurality of irregularities and at least one of the plurality of irregularities having an overhang structure, which has been obtained by selectively plating a surface of a metal member with Zn at a plating thickness of 1 μm or greater and then conducting alloying treatment of the Zn and an underlying metal;
• a semiconductor element fixed to the surface of the metal member except a portion where the Zn alloy layer has been formed;
• and
• a sealing resin covering therewith the Zn alloy layer, the semiconductor element, and the metal member,
• wherein the overhang structure comprises a projection portion at an upper part of the at least one of the plurality of irregularities and a recess portion at a lower port of the at least one of the plurality of irregularities.