Semiconductor storage device and method of manufacturing the same

A method of manufacturing a semiconductor storage device, comprising:

• forming a stacked film on a substrate, the stacked film alternately including a plurality of first insulating layers and a plurality of first films;
• forming a second insulating layer on the stacked film;
• forming a plurality of openings in the stacked film and the second insulating layer;
• processing the second insulating layer such that a width of the second insulating layer sandwiched between the openings is narrower than a width of the stacked film sandwiched between the openings, in at least a portion of the second insulating layer;
• and
• forming a plurality of pillar portions in the plurality of openings, each of the pillar portions sequentially including a first insulator, a charge storage layer, a second insulator, a first semiconductor layer and a third insulator;
• wherein the first semiconductor layer is formed such that a thickness of at least of a portion of the first semiconductor layer formed in the second insulating layer is larger than a thickness of the first semiconductor layer formed in the stacked film.