Patent ID: 7705417

Claim:
A semiconductor device, comprising: a semiconductor substrate; an isolation region including a liner film formed so as to contact a lower surface and a lower side surface of an inner wall of a trench formed in the semiconductor substrate, a first insulating film formed so that at least a part of a side surface and a lower surface of the first insulating film contact the liner film within the trench, and a second insulating film formed so as to contact an upper side of the first insulating film and formed so as to contact an upper side surface of the inner wall of the trench, the second insulating film having a higher etching resistance than that of the first insulating film; and a plurality of semiconductor elements disposed on the semiconductor substrate so as to be isolated from one another by the isolation region, wherein the first insulating film has the lower surface and a lower side surface which contact the liner film, and has an upper surface and an upper side surface which contact the second insulating film.