The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 23, 2021
Filed:
Jan. 07, 2020
Yangtze Memory Technologies Co., Ltd., Hubei, CN;
Yu Ting Zhou, Hubei, CN;
Li Hong Xiao, Hubei, CN;
Jian Xu, Hubei, CN;
Sizhe Li, Hubei, CN;
Zhao Hui Tang, Hubei, CN;
Zhaosong Li, Hubei, CN;
Yangtze Memory Technologies Co., Ltd., Hubei, CN;
Abstract
Disclosed is a method for forming a staircase structure of 3D memory devices, comprising (i) forming a stack of layers on a substrate; (ii) removing a portion of the stack to form a lower region and a upper region; (iii) forming a mask to cover the lower region and the upper region of the stack; (iv) forming a first opening in the mask to expose a first portion of the stack in the lower region and a second opening in the mask to expose a second portion of the stack in the upper region; (v) forming a photoresist layer to cover the stack and the mask; (vi) using a same set of trim-etch processes to pattern the photoresist layer to form a set of staircases in the first opening and the second opening; (vii) removing the photoresist layer and the mask; and repeating (iii), (iv), (v), (vi) and (vii) sequentially.