Patent ID: 8420546

Claim:
A method of producing a semiconductor device, comprising: forming a semiconductor layer over an insulating substrate; forming a gate insulating film over said semiconductor layer; forming a first layer gate electrode over said gate insulating film; forming a second layer gate electrode over said first layer gate electrode with said first layer gate electrode thinner than said second layer gate electrode; forming a resist film comprising a positive type resist and a photo-absorbent over said second layer gate electrode wherein a photo-absorbency of the resist film with respect to a light is increased by adding the photo-absorbent to the positive type resist; patterning said resist film into a first resist pattern by irradiating a light to said resist film to form a taper angle of 45 to 65° formed between a surface of said insulating substrate and a side wall of said resist pattern; forming a first shaped gate electrode by subjecting said first layer gate electrode and said second layer gate electrode to a first dry etching using said first resist pattern as a mask; retreating said first resist pattern by said first dry etching to form a second resist pattern; forming a first impurity area by injecting a single-conductive impurity element into said semiconductor layer using said first shaped gate electrode as a mask; forming a second shaped gate electrode in which said first layer gate electrode is longer than said second layer gate electrode in dimension of the channel direction by subjecting said first shaped gate electrode to a second dry etching using said second resist pattern as a mask; and forming a second impurity area positioned under said first layer gate electrode by injecting said impurity element into said semiconductor layer using said second shaped gate electrode as a mask.