Patent ID: 11955372
Assignee: KIOXIA CORPORATION
Field: Semiconductors (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A semiconductor storage device, comprising:
a semiconductor substrate;
a plurality of circuit regions formed in the semiconductor substrate; and
an element isolation region formed between one of the plurality of circuit regions and another of the plurality of circuit regions, wherein
the element isolation region has a trench shape that includes a sub-trench formed in a bottom corner portion of the element isolation region,
the element isolation region includes a first insulating film and a second insulating film, the first insulating film covering at least an inner wall of the sub-trench,
the sub-trench having a cross-section,
a radius of curvature of the cross-section of the sub-trench at a tip end point of a recessed portion of the sub-trench is half or less of a width of an opening of the trench in a short-side direction of the trench.