公开(公告)号：US20190273088A1

公开(公告)日：2019-09-05

申请号：US15909073

申请日：2018-03-01

Applicant: SANDISK TECHNOLOGIES LLC

Inventor： Zhixin CUI ,  Hiroshi MINAKATA ,  Keigo KITAZAWA ,  Yoshiyuki OKURA

IPC: H01L27/11556 ,  H01L27/11529 ,  H01L27/11573 ,  H01L27/11519 ,  H01L27/11565 ,  H01L29/788 ,  H01L27/11582 ,  H01L23/528

Abstract: A three-dimensional memory device includes a first-tier structure containing a first alternating stack of first insulating layers and first electrically conductive layers that has first stepped surfaces, and a first retro-stepped dielectric material portion contacting the first stepped surfaces of the first alternating stack, and a second-tier structure containing a second alternating stack of second insulating layers and second electrically conductive layers that has second stepped surfaces, and a second retro-stepped dielectric material portion contacting the second stepped surfaces of the second alternating stack. The first retro-stepped dielectric material portion has a higher etch rate than the second retro-stepped dielectric material portion. Memory stack structures vertically extend through the first alternating stack and the second alternating stack. Each of the memory stack structures includes a memory film and a vertical semiconductor channel.