Nonvolatile semiconductor memory device and method for manufacturing same

A method for manufacturing a nonvolatile semiconductor memory device, comprising:

• forming a semiconductor layer on a foundation layer;
• forming a second insulating layer inside the semiconductor layer;
• etching an upper surface of the semiconductor layer until the second insulating layer protrudes from the upper surface of the semiconductor layer;
• forming a stacked body on the second insulating layer and on the semiconductor layer, the stacked body including a plurality of electrode layers stacked alternately with a plurality of first insulating layers, at least one of the plurality of electrode layers including a first portion and a second portion, a first length between the first portion and the foundation layer being longer than a second length between the second portion and the foundation layer, difference between the first length and the second length increasing toward the foundation layer;
• forming a hole piercing the second portion, the hole piercing the stacked body in a direction of the stacking of the plurality of electrode layers and the plurality of first insulating layers, and the hole including a region where maximum length of the hole cut perpendicularly to the direction decreases toward the foundation layer;
• and
• forming a memory film and a semiconductor member on an inner wall of the hole, the memory film being interposed between the semiconductor member and the inner wall.