Patent ID: 8906769

Claim:
A manufacturing method of a semiconductor device, comprising the steps of: (a) providing a semiconductor substrate; (b) forming a first gate electrode via a first gate insulating film and a second gate electrode via a second gate insulating film over the semiconductor substrate; (c) forming a first insulating film over the semiconductor substrate to cover the first gate electrode and the second gate electrode; (d) forming a second insulating film of a different material from that of the first insulating film, over the first insulating film; (e) etching back the second insulating film, forming a first sidewall insulating film made of the second insulating film, over a first side surface of the first insulating film corresponding to a sidewall of the first gate electrode, and forming a second sidewall insulating film made of the second insulating film, over a second side surface of the second insulating film corresponding to a sidewall of the second gate electrode; (f) after the step (e), removing the first sidewall insulating film to leave the second sidewall insulating film; and (g) after the step (f), etching back the second sidewall insulating film and the first insulating film to thereby form a third sidewall insulating film made of the first insulating film, over the sidewall of the first gate electrode, while forming a fourth sidewall insulating film of the first insulating film over the sidewall of the second gate electrode, wherein a width of the third sidewall insulating film is smaller than that of the fourth sidewall insulating film.