Patent ID: 11935889
Assignee: TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY LTD.
Field: Semiconductors (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A method comprising:
in a first etching process, etching a semiconductor substrate to form first recesses in a first device region and second recesses in a second device region, wherein a first semiconductor strip is formed between the first recesses, and a semiconductor strip group comprising a second plurality of semiconductor strips is formed and defined by the second recesses;
forming an etching mask comprising:
a first portion covering the first semiconductor strip, wherein the first portion extends laterally beyond first opposing sidewalls of the first semiconductor strip;
a second portion covering the semiconductor strip group, wherein the second portion extends laterally beyond second opposing sidewalls of the semiconductor strip group, wherein a first sidewall of one of the first semiconductor strip and the second plurality of semiconductor strips contacts a second sidewall of the etching mask to form an interface;

in a second etching process, etching the semiconductor substrate, wherein in the second etching process, the first portion of the etching mask is recessed laterally to the first opposing sidewalls of the first semiconductor strip, and the first recesses extend downwardly; and
removing remaining portions of the etching mask, wherein at a time after the second etching process is performed and before the remaining portions of the etching mask are removed, the first sidewall is exposed.