US 12,261,080 B2
Method of making a three-dimensional memory device using composite hard masks for formation of deep via openings
Roshan Jayakhar Tirukkonda, Milpitas, CA (US); Monica Titus, Santa Clara, CA (US); Senaka Kanakamedala, San Jose, CA (US); Raghuveer S. Makala, Campbell, CA (US); Rahul Sharangpani, Fremont, CA (US); and Adarsh Rajashekhar, Santa Clara, CA (US)
Assigned to Sandisk Technologies, Inc., Milpitas, CA (US)
Filed by SANDISK TECHNOLOGIES LLC, Addison, TX (US)
Filed on Mar. 31, 2022, as Appl. No. 17/657,521.
Application 17/657,521 is a continuation in part of application No. 17/590,278, filed on Feb. 1, 2022.
Application 17/590,278 is a continuation in part of application No. 17/508,036, filed on Oct. 22, 2021.
Application 17/508,036 is a continuation in part of application No. 17/494,114, filed on Oct. 5, 2021.
Application 17/494,114 is a continuation in part of application No. 17/355,955, filed on Jun. 23, 2021, granted, now 11,972,954.
Application 17/355,955 is a continuation in part of application No. 17/136,471, filed on Dec. 29, 2020, granted, now 12,010,841.
Prior Publication US 2022/0223470 A1, Jul. 14, 2022
Int. Cl. H01L 21/768 (2006.01); H01L 21/306 (2006.01)
CPC H01L 21/76831 (2013.01) [H01L 21/30608 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method of forming a structure, comprising:
forming an alternating stack of first material layers and second material layers over a substrate;
forming a mask layer over the alternating stack;
forming a cavity in the mask layer;
forming a first cladding liner on a sidewall of the cavity in the mask layer; and
forming a via opening in the alternating stack by performing an anisotropic etch process that transfers a pattern of the cavity in the mask layer through the alternating stack using a combination of the first cladding liner and the mask layer as an etch mask;
wherein:
the mask layer comprises a first patterning film having a concave upper surface; and
the first cladding liner comprises a cylindrical cladding film that is formed by conformally depositing a cladding material layer on physically exposed surfaces of the cavity and over a top surface of the first patterning film and removing horizontally-extending portions of the cladding material layer by anisotropically etching the cladding material layer.