Patent ID: 8399313

Claim:
A method for manufacturing a semiconductor device comprising the steps of: forming a first conductive layer made from aluminum as its main component over a substrate; forming a second conductive layer made from a material different from that used for forming the first conductive layer over the first conductive layer; forming a first gate electrode and a second gate electrode by patterning the first conductive layer and the second conductive layer; forming a gate insulating film over the first gate electrode and the second gate electrode; forming a semiconductor film over the gate insulating film; crystallizing the semiconductor film by heating the semiconductor film after introducing a catalytic element into the semiconductor film; forming a first island-shaped semiconductor region and a second island-shaped semiconductor region by patterning the semiconductor film; and heating the first island-shaped semiconductor region and the second island-shaped semiconductor region, thereby gettering the catalytic element and a metal element mixed into the semiconductor film in the step of forming the semiconductor film.