Patent ID: 11894237
Assignee: TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY LTD.
Field: Semiconductors (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A method comprising:
forming a first mask layer over a target layer;
forming a second mask layer over the first mask layer, wherein the second mask layer is patterned with an opening therein to reveal a first portion of the first mask layer, and wherein a second portion of the first mask layer is covered by the second mask layer;
depositing a third mask layer comprising:
a first part over the second mask layer; and
a second part extending into the opening to contact the first mask layer;

etching the third mask layer and the first mask layer, wherein after the etching, the first mask layer comprises:
a remaining portion of the first portion, wherein portions of the first mask layer on opposite sides of the remaining portion are removed; and

transferring patterns of the first mask layer into the target layer.