Patent ID: 7611947

Claim:
A method of manufacturing a semiconductor device in which a trench-type transistor, a high breakdown voltage transistor, and an ordinary breakdown voltage transistor are provided on a semiconductor substrate, comprising the steps of: forming element isolation layers on a surface of a semiconductor substrate for isolating a trench-type transistor, a high breakdown voltage transistor, and an ordinary breakdown voltage transistor; forming a trench in a trench-type transistor region; forming a gate insulating film and a gate material layer on the semiconductor substrate and in the trench; forming a first photoresist layer on the semiconductor substrate so as to expose extension region formation portions of the trench-type transistor region and the high breakdown voltage transistor region; forming extension regions of the trench-type transistor and the high breakdown voltage transistor by performing ion implantation in the trench-type transistor region and the high breakdown voltage transistor region; forming a second photoresist layer on the semiconductor substrate so as to cover the trench-type transistor region and the high breakdown voltage transistor region and expose the ordinary breakdown voltage transistor region; and forming extension regions of the ordinary breakdown voltage transistor by implanting ions in the ordinary breakdown voltage transistor region.