Patent ID: 7374981

Claim:
A method for manufacturing a thin film transistor, said method comprising: forming a semiconductor film over an insulating substrate; forming a first insulating film over the semiconductor film; forming a first conductive film over the first insulating film; heat-treating the semiconductor film, the first insulating film, and the first conductive film; patterning the semiconductor film, the first insulating film, and the first conductive film into island shapes by a photomask after heat-treating the semiconductor film, the first insulating film, and the first conductive film to form an island-shaped semiconductor film, an island-shaped gate insulating film, and a first island-shaped conductive film after the heat-treating step; forming a second insulating film over the first island-shaped conductive film; etching the second insulating film anisotropically to form a side wall covering side faces of the island-shaped semiconductor film and the island-shaped gate insulating film in a self-aligned manner; forming a second conductive film over the island-shaped gate insulating film after forming the side wall; and patterning the first island-shaped conductive film and the second conductive film to form a gate electrode.