Patent ID: 7745271

Claim:
A method of manufacturing a semiconductor device, the method comprising: forming a conductive film over a first semiconductor and a second semiconductor with an insulating film therebetween; forming a first resist pattern on the conductive film over the first semiconductor; forming a second resist pattern on the conductive film over the second semiconductor by using a photomask having a diffraction grating pattern or a reticle having a diffraction grating pattern, wherein a thickness of an edge portion of the second resist pattern is smaller than a thickness of a middle portion of the second resist pattern; forming a first gate electrode over the first semiconductor by dry etching using the first resist pattern; and forming a second gate electrode by dry etching using the second resist pattern over the second semiconductor, wherein a thickness of an edge portion of the second gate electrode is smaller than a thickness of a middle portion of the second gate electrode; introducing an impurity element into the first semiconductor with the first gate electrode as a mask to form a first impurity region in the first semiconductor, wherein the first impurity region is not overlapped with the first gate electrode; and introducing the impurity element into the second semiconductor with the second gate electrode as a mask to form a second impurity region and a third impurity region in the second semiconductor, wherein the second impurity region is not overlapped with the second gate electrode and the third impurity region is overlapped with the edge portion of the second gate electrode.