Patent ID: 7804142

Claim:
A semiconductor device comprising: a pixel portion; and an external input terminal portion, wherein the pixel portion comprises: a semiconductor layer over an insulating surface; a gate insulating film on the semiconductor layer; and a gate electrode on the gate insulating film, wherein the semiconductor layer comprises a channel formation region, at least one LDD region in contact with the channel formation region, and a source region or a drain region in contact with the LDD region, wherein the gate electrode has a taper shape, wherein the gate electrode comprises a laminate of a fourth electrode, a fifth electrode and a sixth electrode, and at least one of the fourth electrode, the fifth electrode and the sixth electrode comprises copper, and wherein the external input terminal portion has a first portion and a second portion over the gate insulating film, the first portion including a conductive film comprising the fourth electrode, the fifth electrode and the sixth electrode, and the second portion including an interlayer insulating film, and wherein the first portion and the second portion are arranged alternately over the gate insulating film.