US 12,010,841 B2
Method of making a three-dimensional memory device using composite hard masks for formation of deep via openings
Monica Titus, Santa Clara, CA (US); Senaka Kanakamedala, San Jose, CA (US); Rahul Sharangpani, Fremont, CA (US); Raghuveer S. Makala, Campbell, CA (US); and Yao-Sheng Lee, Tampa, FL (US)
Assigned to SANDISK TECHNOLOGIES LLC, Addison, TX (US)
Filed by SANDISK TECHNOLOGIES LLC, Addison, TX (US)
Filed on Dec. 29, 2020, as Appl. No. 17/136,471.
Prior Publication US 2022/0208785 A1, Jun. 30, 2022
Int. Cl. H10B 43/27 (2023.01); H10B 41/10 (2023.01); H10B 41/27 (2023.01); H10B 43/10 (2023.01)
CPC H10B 43/27 (2023.02) [H10B 41/10 (2023.02); H10B 41/27 (2023.02); H10B 43/10 (2023.02)] 22 Claims
OG exemplary drawing
 
1. A method of forming a semiconductor structure, comprising:
forming an alternating stack of first material layers and second material layers over a substrate;
forming a hard mask layer over the alternating stack;
applying and patterning a photoresist layer over the hard mask layer, wherein openings are formed in the photoresist layer;
forming cavities in the hard mask layer by performing a first anisotropic etch process that transfers a pattern of the openings in the photoresist layer through the hard mask layer;
forming via openings through an upper portion of the alternating stack by performing a second anisotropic etch process that transfers a pattern of the cavities in the hard mask layer;
forming a cladding liner on sidewalls of the cavities in the hard mask layer; and
vertically extending the via openings through all layers within the alternating stack by performing a third anisotropic etch process that employs a combination of the cladding liner and the hard mask layer as an etch mask;
wherein the cladding liner is deposited by a selective deposition process that grows a material of the cladding liner from physically exposed surfaces of the hard mask layer without growth of the material of the cladding liner from physically exposed surfaces of the alternating stack.