US 11,856,776 B2
Structure of 3D NAND memory device and method of forming the same
Li Hong Xiao, Wuhan (CN); and Li Xun Gu, Wuhan (CN)
Assigned to Yangtze Memory Technologies Co., Ltd., Wuhan (CN)
Filed by Yangtze Memory Technologies Co., Ltd., Wuhan (CN)
Filed on Sep. 28, 2021, as Appl. No. 17/486,951.
Application 17/486,951 is a division of application No. 16/198,736, filed on Nov. 21, 2018, abandoned.
Application 16/198,736 is a continuation of application No. PCT/CN2018/112177, filed on Oct. 26, 2018.
Prior Publication US 2022/0013541 A1, Jan. 13, 2022
Int. Cl. H10B 43/27 (2023.01); H01L 21/28 (2006.01); H01L 21/02 (2006.01); H01L 21/311 (2006.01); H10B 43/35 (2023.01)
CPC H10B 43/27 (2023.02) [H01L 21/02532 (2013.01); H01L 21/02636 (2013.01); H01L 21/31111 (2013.01); H01L 21/31144 (2013.01); H01L 29/40117 (2019.08); H10B 43/35 (2023.02)] 10 Claims
OG exemplary drawing
 
1. A method of forming a structure of 3D NAND memory device, comprising:
forming a first stack layer on a substrate;
forming a first channel hole extending through said first stack layer;
forming a block layer on a surface of said first stack layer and on a sidewall of said first channel hole;
forming a sacrificial layer in said first channel hole;
forming a second stack layer on said first stack layer and said sacrificial layer;
performing a first etch process to form a second channel hole extending through said second stack layer and completely overlapping said first channel hole and to remove said sacrificial layer in said first channel hole, wherein a minimum diameter of said second channel hole is larger than a maximum diameter of said first channel hole;
removing said block layer exposed from said second channel hole; and
forming a function layer on a surface of said first channel hole and said second channel hole.