Patent ID: 7807516

Claim:
A manufacturing method of a semiconductor device, the method comprising: forming an insulating film over a semiconductor layer; forming a first conductive film over the insulating film; forming a second conductive film over the first conductive film; forming a resist pattern having a first region and a second region over the second conductive film, with a photomask or a reticle having a diffraction grating pattern or a semi-transparent portion; selectively etching the first conductive film and the second conductive film to form a first gate electrode and a second gate electrode comprising a third region, a fourth region and a fifth region; injecting an impurity element into the semiconductor layer with the second gate electrode as a mask to form a source region and a drain region in the semiconductor layer; and injecting an impurity element into the semiconductor layer through the fourth region and the fifth region, with the first gate electrode as a mask to form a first impurity region and a second impurity region in a region of the semiconductor layer overlapped with the fourth region and the fifth region, wherein a width of the first impurity region is larger than that of the second impurity region, wherein a thickness of the first region is larger than that of the second region, wherein the third region is provided between the fourth region and the fifth region, wherein the first gate electrode is provided over the third region, and wherein a width of the fourth region is larger than that of the fifth region.