Staircase formation in three-dimensional memory device
AssigneeYangtze Memory Technologies Co., Ltd.
InventorYu Ting Zhou
Life of this patent
Estimating the term…
Abstract
A method for forming a staircase structure of 3D memory, including: forming an alternating layer stack comprising a plurality of dielectric layer pairs disposed over a substrate; forming a first mask stack over the alternating layer stack; patterning the first mask stack to define a staircase region comprising a number of N sub-staircase regions over the alternating layer stack using a lithography process and N is greater than 1; forming a first staircase structure over the staircase region, the first staircase structure has a number of M steps at each of the staircase regions and M is greater than 1; and forming a second staircase structure on the first staircase structure, the second staircase structure has a number of 2*N*M steps at the staircase region.
Claims20
A memory device, comprising:
- an alternating layer stack, comprising a conductor layer and an insulating layer alternatingly stacked in a first direction;
- a storage structure, comprising a semiconductor channel extending through the alternating layer stack in the first direction;
- and
- a staircase structure, comprising two or more sub-staircase structures in a second direction perpendicular to the first direction, wherein each of the two or more sub-staircase structures is configured to expose portions of different conductor layers in the alternating layer stack such that each conductor layer is accessible by a fan-out connection.
A memory device, comprising:
- an alternating layer stack comprising conductor/dielectric layer pairs;
- a storage structure comprising a vertical semiconductor channel;
- a staircase structure adjacent to the storage structure and exposing a portion of the alternating layer stack, wherein:
- the staircase structure comprises N number of sub-staircase structures;
- at least one of the N number of sub-staircase structures comprises 2*M number of staircase steps;
- each of the 2*M number of staircase steps corresponds to a different conductor/dielectric pair;
- and
- N and M are greater than 1.
Dependencies are inferred from the claim text.