Patent ID: 6737306
Filing Date: 2004-05-18
Classification: G02F,H01L

Abstract:
A method of manufacturing a semiconductor device having a driving circuit and a pixel portion over an insulating surface, the method comprising:forming a semiconductor layer over the insulating surface; forming a first insulating film over the semiconductor layer; forming a gate electrode over the first insulating film; doping first impurity elements at a first concentration providing n-type into the semiconductor layer using the gate electrode as a mask to form a first n-type impurity region; etching the gate electrode to form a tapered portion of the gate electrode; doping second impurity elements at a second concentration smaller than the first concentration providing n-type into the semiconductor layer having the first n-type impurity region while passing through the tapered portion of the gate electrode to form a second n-type impurity region between the first n-type impurity region and a channel-forming region; forming a second insulating film so as to cover the gate electrode; forming a source wire of the pixel portion over the second insulating film; forming a third insulating film so as to cover the source wire of the pixel portion; and forming a source wire of the driving circuit and a gate wire of the pixel portion over the third insulating film.