US 11,901,217 B2
Method and apparatus for making shallow trench structure
Tzujen Lin, Anhui (CN); Chihchiang Yang, Anhui (CN); Chengwei Lin, Anhui (CN); and Yucheng Lin, Anhui (CN)
Assigned to NEXCHIP SEMICONDUCTOR CORPORATION, Hefei (CN)
Filed by NEXCHIP SEMICONDUCTOR CORPORATION, Anhui (CN)
Filed on Apr. 30, 2021, as Appl. No. 17/246,588.
Claims priority of application No. 202011012959.9 (CN), filed on Sep. 24, 2020.
Prior Publication US 2022/0093450 A1, Mar. 24, 2022
Int. Cl. H01L 21/762 (2006.01); H01L 21/3213 (2006.01); H01L 21/311 (2006.01)
CPC H01L 21/76224 (2013.01) [H01L 21/31111 (2013.01); H01L 21/31116 (2013.01); H01L 21/32137 (2013.01)] 12 Claims
OG exemplary drawing
 
1. A method for making a shallow trench structure, which at least comprises the following:
preparing a substrate;
forming a first material layer on one side of the substrate;
forming a second material layer on the first material layer;
forming a shallow trench, wherein the shallow trench penetrates the second material layer and the first material layer and extends into the substrate;
performing a first lateral etching on the second material layer from the shallow trench to both sides by using wet etching;
performing a second lateral etching on the first material layer from the shallow trench to both sides by using dry etching.