Patent ID: 8853020

Claim:
A method of manufacturing a semiconductor device comprising: forming a gate electrode on a semiconductor substrate of a first conductive type; forming a first insulating film on the semiconductor substrate including the gate electrode; etching the first insulating film to form first sidewall spacers on both sides of the gate electrode; doping second conductive type impurities with a low concentration on the surface of the semiconductor substrate using the first sidewall spacers as a mask; forming a second insulating film on the semiconductor substrate including the first sidewall spacers; etching the second insulating film to form second sidewall spacers on the first sidewall spacers; and doping second conductive type impurities with a high concentration on the surface of the semiconductor substrate using the second sidewall spacers as a mask, wherein each of the first sidewall spacers has a footing portion including a slope, an angle between a tangent line at a point of the slope and the surface of the semiconductor substrate becomes gradually small when the point becomes closer to the surface of the semiconductor substrate, and wherein the first sidewall spacers are formed by terminating the etching of the first insulating film at the same time when detecting the exposure of the surface of the semiconductor substrate by monitoring a wavelength of plasma when etching the first insulating film, or after over-etching for a certain time.