Patent ID: 7382015

Claim:
A nonvolatile semiconductor memory device comprising: a semiconductor substrate having a first upper surface; an element isolation portion protruding from the first upper surface, the element isolation portion including an upper end portion having a highest portion and a recess, the recess having a bottom portion and an inner surface; a first gate electrode film including a second upper surface, the first gate electrode film formed above the first upper surface via a first insulating film, a height of the second upper surface from the first upper surface being lower than a height of the highest portion and being higher than a height of the bottom portion from the first upper surface; a second gate electrode film including a third upper surface and an upper side surface, the second gate electrode film formed on the first gate electrode film and separated from an adjacent gate electrode film by the element isolation portion, a height of the third upper surface from the first upper surface being higher than a height of the highest portion from the first upper surface, the upper side surface being continuous with the inner side surface; a second insulating film formed directly and continuously on the second gate electrode film and the inner side surface; and a third gate electrode film formed on the second insulating film and embedded inside of the inner side surface in the recess.