Patent ID: 7873086

Claim:
A semiconductor device comprising: a semiconductor element ( 03 ) having an asymmetric temperature distribution including a higher temperature side and a lower temperature side during operation, and; a lead frame ( 01 ) comprising: a mounting part ( 04 ) for mounting the semiconductor element; a first lead connected to the mounting part; a second lead adjacent to the first lead; a third lead adjacent to the first lead; wherein the first lead is between the second lead and the third lead, said first, second and third leads being held in their positions by resin; the second lead has an inner lead ( 05 a 1 ) longer than an inner lead ( 05 a 2 ) of the third lead, and the semiconductor element is mounted on the lead frame with its higher temperature side closer than the lower temperature side to the third lead for improved dissipation of heat originating from the higher temperature side of the semiconductor element.