Semiconductor storage device

A semiconductor storage device comprising:

• a stacked body in which a plurality of first conductive layers is stacked with a first insulating layer interposed between the plurality of first conductive layers, the stacked body having a stepped region in which end portions of the plurality of first conductive layers are terminated in a stepped shape and a memory region in which a plurality of memory cells is arranged;
• a second insulating layer that covers the stepped region and spreads toward an outside of the stepped region, and reaches at least a height of an upper surface of the stacked body in the memory region;
• a structural portion having a longitudinal direction along a first direction that intersects an ascending/descending direction of the stepped region, the structural portion extending in a thickness direction of the second insulating layer, the structural portion interrupting spread of the second insulating layer outside the stepped region in a second direction along the ascending/descending direction;
• and
• a split portion having a longitudinal direction along the second direction, extending in a stacking direction of the stacked body, and splitting the stacked body in the first direction, wherein
• the split portion contains a first material, and
• the structural portion
• contains the first material in an upper portion and
• contains a second material, which has tensile stress and is different from the first material, in a lower portion.