Patent ID: 8436419

Claim:
A semiconductor device comprising: a low voltage circuit section; a high voltage circuit section; a high-breakdown-voltage transistor configured to perform power conversion between the low voltage circuit section and the high voltage circuit section, the high-breakdown-voltage transistor including a semiconductor layer of a predetermined conductivity type, the semiconductor layer having front and back sides opposite to each other, the semiconductor layer including an element portion electrically isolated by a trench; and a power supply wiring formed on the front side of the semiconductor layer and configured to apply a voltage to the high voltage circuit section, wherein the element portion has a wiring member on the front side of the semiconductor layer and a lead frame on the back side of the semiconductor layer, the element portion being configured as a vertical transistor that causes an electric current to flow in a thickness direction of the semiconductor layer between the wiring member and the lead frame, wherein the lead frame has a projection projecting from an edge of the back side of the semiconductor layer, and wherein the projection of the lead frame is electrically coupled to the power supply wiring through a bonding wire.