Nonvolatile semiconductor memory device and method of manufacturing the same

A nonvolatile semiconductor memory device, comprising:

• a semiconductor layer provided on a substrate and extending in a first direction;
• a first gate insulating film formed on the semiconductor layer;
• a plurality of floating gate electrodes formed on the first gate insulating film along the semiconductor layer;
• a second gate insulating film formed on an upper surface of the floating gate electrode;
• a plurality of control gate electrodes respectively facing the upper surfaces of the plurality of floating gate electrodes via the second gate insulating film, and extending in a second direction intersecting the first direction;
• and
• an upper insulating film formed on an upper portion of the plurality of control gate electrodes,
• a height of an upper surface of the upper insulating film being a first height at a first position in the second direction and being a second height lower than the first height at a second position different from the first position in the second direction;
• the upper insulating film comprising:
• a plurality of first insulating layers formed in the second direction, each extending in the first direction;
• and
• a second insulating layer positioned on the upper surface of the plurality of the first insulating layers and between the plurality of first insulating layers,
• the first insulating layer being positioned at the first position in the second direction and a height of the upper surface of the second insulating layer being the first height at the first position, and
• a portion between the first insulating layers being positioned at the second position in the second direction and a height of the upper surface of the second insulating layer being the second height at the second position.