Patent ID: 7410847

Claim:
A method for manufacturing a semiconductor device comprising the steps of: forming a gate electrode over a substrate; forming a gate insulating film over the gate electrode and forming a semiconductor film over the gate insulating film without exposing to the atmosphere; forming an insulating film over the semiconductor film; forming a first mask over the insulating film; introducing a first impurity element into the semiconductor film by using the first mask; forming a second mask so as to overlap with a first part of the first mask, and in contact with a part of the insulating film and the first part of the first mask to expose a second part of the first mask; introducing a second impurity element into the semiconductor film by using the second mask to form an LDD region and a source or drain region; and forming an interlayer insulating film over the first mask and the second mask, and in contact with the second part of the first mask, the second mask, and the insulating film, wherein the LDD region is in contact with one end of a channel formation region, and one of the source and drain region is in contact with the other end of the channel formation region.