US 11,967,533 B2
Semiconductor devices and methods of manufacturing thereof
Shu-Uei Jang, Hsinchu (TW); Shu-Yuan Ku, Zhubei (TW); and Shih-Yao Lin, New Taipei (TW)
Assigned to Taiwan Semiconductor Manufacturing Company, Ltd., Hsinchu (TW)
Filed by Taiwan Semiconductor Manufacturing Company, Ltd., Hsinchu (TW)
Filed on Jun. 23, 2021, as Appl. No. 17/355,444.
Prior Publication US 2022/0415716 A1, Dec. 29, 2022
Int. Cl. H01L 29/78 (2006.01); H01L 21/311 (2006.01); H01L 21/3213 (2006.01); H01L 21/8234 (2006.01); H01L 27/088 (2006.01); H01L 29/66 (2006.01)
CPC H01L 21/823481 (2013.01) [H01L 21/31116 (2013.01); H01L 21/32137 (2013.01); H01L 21/823431 (2013.01); H01L 27/0886 (2013.01); H01L 29/66545 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method of making a semiconductor device, comprising:
forming a first semiconductor fin and a second semiconductor fin over a substrate that both extend along a first direction;
forming a dielectric fin that extends along the first direction and is disposed between the first and second semiconductor fins;
forming a dummy gate structure that extends along a second direction perpendicular to the first direction and straddles the first and second semiconductor fins and the dielectric fin;
removing a portion of the dummy gate structure over the dielectric fin to form a trench by performing an etching process that includes a plurality of stages, wherein each of the plurality of stages includes a combination of anisotropic etching and isotropic etching such that a variation of a distance between inner sidewalls of the trench along the second direction is within a threshold, wherein the inner sidewalls of the trench face each other along the second direction; and
filling the trench with a dielectric material to form a gate isolation structure;
wherein the plurality of stages comprises:
a first stage configured to form a first portion of the trench in a valley-shaped profile;
a second stage configured to form a second portion of the trench in a curvature-based U-shaped profile; and
a third stage configured to form a third portion of the trench in an edge-based U-shaped profile.