Patent ID: 7399662

Claim:
A method of manufacturing a thin film transistor device, comprising: (1) a step for forming a semiconductor film on a substrate, and patterning said semiconductor film, thus forming a first semiconductor film in a low-voltage driven thin film transistor formation region and a second semiconductor film in a high-voltage driven thin film transistor formation region; (2) a step for forming a first insulating film on said first and second semiconductor films; (3) a step for forming a first gate electrode on said first insulating film in said low-voltage driven thin film transistor formation region; (4) a step for forming a second insulating film on the entire surface of the resultant structure above said substrate; (5) a step for forming a second gate electrode on said second insulating film in said high-voltage driven thin film transistor formation region; and (6) a step for etching said first and second insulating films, thus forming a first gate insulating film below said first gate electrode and a second gate insulating film below said second gate electrode, said second gate insulating film having a width larger than that of said second gate electrode.