Patent ID: 7667307

Claim:
A semiconductor device comprising: a semiconductor chip mounted over a die pad portion of a lead frame and sealed in a resin package; and an outer lead portion of the lead frame exposed from the resin package, wherein the lead frame has a gate lead, a source lead, a drain lead and the die pad portion integrated with the drain lead, wherein the semiconductor chip has, over a main surface thereof, a gate pad coupled to a gate electrode of a power MOSFET, and a source pad coupled to a source of the power MOSFET and having a greater area than the gate pad, wherein a backside of the semiconductor chip forming a drain of the power MOSFET is bonded onto the die pad portion with an Ag paste, wherein the source lead and the source pad are coupled via an Al ribbon, and wherein the elastic modulus (Pa) of the Ag paste satisfies the following relation: Pa<2.6×(adhesion thickness of Ag paste)/(displacement permitting ultrasonic bonding of Al ribbon)×(shear strength of Ag paste).