Patent ID: 7582928

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 side 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, 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; a second insulating film formed on the second gate electrode film and the inner side surface of the recess, the second insulating film contacting to the whole inner side surface of the recess; and a third gate electrode film formed on the second insulating film and embedded inside of the inner side surface in the recess.