Title:
METHODS FOR FORMING STAIRS IN THREE-DIMENSIONAL MEMORY DEVICES
Document Type and Number:
WIPO Patent Application WO/2022/151033
Kind Code:
A1
Abstract:
A method for forming a three-dimensional (3D) memory. The method includes forming a stack structure having interleaved a plurality of stack first layers (204) and a plurality of stack second layers (206), forming a stair (202-1, 202-2) in the stack structure, the stair (202-1, 202-2) having one of the stack first layers (204) on a top surface, and forming a layer of sacrificial material (208, 210) having a first portion (208-1, 210-1) over a side surface of the stair (202-1, 202-2) and a second portion (208-2, 210-2) over the top surface of the stair (202-1, 202-2). The method also includes partially removing the first portion (210-1) of the layer of sacrificial material (208, 210) using an anisotropic etching process and removing a remaining portion of the first portion (208-1) of the layer of sacrificial material (208, 210) using an isotropic etching process.
Inventors:
WANG XIANGNING (CN)
YUAN BIN (CN)
ZUO CHEN (CN)
YANG ZHU (CN)
XU ZONGKE (CN)
YUAN BIN (CN)
ZUO CHEN (CN)
YANG ZHU (CN)
XU ZONGKE (CN)
Application Number:
PCT/CN2021/071445
Publication Date:
July 21, 2022
Filing Date:
January 13, 2021
Export Citation:
Assignee:
YANGTZE MEMORY TECH CO LTD (CN)
International Classes:
H01L27/115; H01L27/1157; H01L27/11582
Foreign References:
| US20190148398A1 | 2019-05-16 | |||
| US20190363006A1 | 2019-11-28 | |||
| US20200152654A1 | 2020-05-14 | |||
| US20180330985A1 | 2018-11-15 | |||
| CN111033729A | 2020-04-17 |
Attorney, Agent or Firm:
NTD UNIVATION INTELLECTUAL PROPERTY AGENCY LTD. (CN)
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