US 11,894,237 B2
Ultra narrow trench patterning with dry plasma etching
Chao-Hsuan Chen, Hsinchu (TW); and Yuan-Sheng Huang, Taichung (TW)
Assigned to TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY, LTD., Hsinchu (TW)
Filed by Taiwan Semiconductor Manufacturing Co., Ltd., Hsinchu (TW)
Filed on May 27, 2022, as Appl. No. 17/826,528.
Application 17/826,528 is a continuation of application No. 17/073,847, filed on Oct. 19, 2020, granted, now 11,348,800.
Application 17/073,847 is a continuation of application No. 16/354,364, filed on Mar. 15, 2019, granted, now 10,811,270, issued on Oct. 20, 2020.
Prior Publication US 2022/0285165 A1, Sep. 8, 2022
Int. Cl. H01L 21/308 (2006.01); H01L 21/8234 (2006.01); H01L 21/3213 (2006.01)
CPC H01L 21/3088 (2013.01) [H01L 21/3086 (2013.01); H01L 21/32139 (2013.01); H01L 21/823431 (2013.01); H01L 21/823437 (2013.01)] 20 Claims
OG exemplary drawing
 
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.