公开(公告)号：US09673216B1

公开(公告)日：2017-06-06

申请号：US15212682

申请日：2016-07-18

Applicant: SanDisk Technologies LLC

Inventor： Ashish Baraskar ,  Liang Pang ,  Yingda Dong ,  Ching-huang Lu

IPC: H01L27/115 ,  H01L21/311 ,  H01L27/11582 ,  H01L21/02 ,  H01L21/28 ,  H01L27/11556

CPC classification number: H01L27/11582 ,  H01L21/02063 ,  H01L21/02164 ,  H01L21/0217 ,  H01L21/02532 ,  H01L21/02636 ,  H01L21/28273 ,  H01L21/28282 ,  H01L21/31111 ,  H01L27/11556 ,  H01L27/1157

Abstract: Disclosed herein are methods of forming memory cell films in 3D memory. An opening having a sidewall may be formed through a stack of alternating layers of silicon oxide and silicon nitride. Bird's beaks may be formed in the silicon nitride at interfaces with the silicon oxide. In one aspect, bird's beaks are formed using a wet SiN etch. In one aspect, bird's beaks are formed by oxidizing SiN. A dilute hydrofluoric acid (DHF) clean may be performed within the opening after forming the bird's beaks in the silicon nitride. A memory cell film may be formed in the opening after performing the DHF clean. The memory cell film is straight, or nearly straight, from top to bottom in a memory hole. The memory cell film is not as susceptible to parasitic charge trapping as a memory cell film having a wavy contour. Therefore, neighbor WL interference may be reduced.