Patent ID: 11950418
Assignee: YANGTZE MEMORY TECHNOLOGIES CO., LTD.
Field: nan (nan)
Classification: CPC H | IPC H

Claim 10:
11. A method for forming a three-dimensional (3D) memory device, comprising:
forming a plurality of stairs in a dielectric stack comprising interleaved a plurality of sacrificial layers and a plurality of dielectric layers, wherein each stair comprises one or more sacrificial layers of the plurality of sacrificial layers and one or more dielectric layers of the plurality of dielectric layers, each stair exposing one of the dielectric layers on a top surface and the one or more sacrificial layers on a side surface;
forming an insulating portion to cover the side surface of each stair to cover the one or more sacrificial layers;
forming a sacrificial film, wherein the sacrificial film comprises a first portion covering a side surface of the insulating portion, and a second portion covering the top surface of each stair and a top surface of the insulating portion and being in contact with the one of sacrificial layers; and
removing the first portion of the sacrificial film to expose the insulating portion on the side surface of each stair, wherein the second portion is retained covering the top surface of the insulating portion, and a bottom surface of the insulating portion is in contact with a top surface of adjacent lower stair.