Patent ID: 7387921

Claim:
A method of manufacturing a semiconductor device, comprising: forming a gate electrode on a main surface of a semiconductor substrate via a gate insulating film; laminating sequentially a first insulating film with oxidation resistance and a silicon film on the main surface of the semiconductor substrate on which the gate electrode is formed; eliminating selectively the silicon film except for a side face of the gate electrode, and oxidizing the silicon film to transform it into a first silicon oxide film; eliminating the first insulating film on the main surface of the semiconductor substrate by using the first silicon oxide film as a mask, and then forming a first impurity layer on the main surface of the semiconductor substrate; laminating a sidewall insulating film thicker than the first silicon oxide film on the side face of the gate electrode on which the first silicon oxide film is formed; and forming a second impurity layer which has the same conduction type as that of the first impurity layer and has impurity concentration higher than that of the first impurity layer close to the first impurity layer by using the sidewall insulating film as a mask.