Patent ID: 8048749

Claim:
A method for manufacturing a semiconductor device, the method comprising: forming a gate electrode over a substrate; forming a gate insulating film over the gate electrode so that a projection portion is formed over the substrate by the formation of the gate electrode and the gate insulating film; forming a semiconductor film comprising amorphous silicon over the gate electrode with the gate insulating film interposed therebetween; crystallizing the semiconductor film by irradiating a laser light; forming a resist over the semiconductor film after the crystallizing step; exposing the resist with light through the substrate; removing a portion of the resist which is exposed by the light; adding an impurity element imparting one conductivity type to the semiconductor film using, as a mask, the resist which remains after the removal of the portion, wherein the semiconductor film comprising amorphous silicon has a first portion over the gate electrode and a second portion adjacent to the first portion, and the first portion flows into the second portion in the crystallizing step, and wherein after the crystallizing step, a thickness of the first portion is smaller than that of the second portion.