Patent ID: 8735966

Claim:
A nonvolatile semiconductor memory device comprising: a semiconductor substrate; first and second memory cells disposed on the semiconductor substrate in a first direction; and an element isolation insulating film disposed between the first and second memory cells in the first direction, wherein the first and second memory cells have: first and second tunnel insulating films, respectively, formed on the semiconductor substrate; first and second insulating films which are formed on the first and second tunnel insulating films, respectively; a block insulating film formed on the first and second insulating films; and a first gate electrode formed on the block insulating film, and a part of the element isolation insulating film and a part of the block insulating film exist between a side surface of the first insulating film and a side surface of the second insulating film, an uppermost surface of the block insulating film on the element isolation insulating film is higher than a lowermost surface of the block insulating film on the first and second insulating films, and the side surfaces of the first and second insulating films and the side surfaces of the first and second tunnel insulating films form one continuous plane.