Patent ID: 7015107

Claim:
A method of manufacturing a semiconductor device comprising the steps of: (a) forming a gate insulating film on a major surface of a semiconductor substrate and a gate electrode on said semiconductor substrate through said gate insulating film; (b) forming a dummy sidewall to cover side surfaces of said gate electrode and said gate insulating film and a predetermined area of said major surface which extends laterally from said side surfaces; (c) forming an impurity region by introducing an impurity into said major surface using said dummy sidewall and said gate electrode as masks; (d) forming a protective oxide film on said gate electrode and on said major surface using said dummy sidewall as a mask, said step (d) being performed either prior to or after said step (c); (e) reducing a thickness of said dummy sidewall, said step (e) being performed after said step (d); and (f) extending said impurity region under part of said gate insulating film using a dummy sidewall left after said step (e) and said gate electrode as masks.