US 12,327,732 B2
Method to improve profile control during selective etching of silicon nitride spacers
Xiangyu Guo, Newark, DE (US); James Royer, Fremont, CA (US); Venkateswara R. Pallem, Branchburg, NJ (US); and Nathan Stafford, Newark, DE (US)
Assigned to American Air Liquide, Inc., Fremont, CA (US)
Filed by AMERICAN AIR LIQUIDE, INC., Fremont, CA (US)
Filed on Oct. 25, 2023, as Appl. No. 18/383,667.
Application 18/383,667 is a continuation of application No. 17/945,631, filed on Sep. 15, 2022, granted, now 11,837,474.
Application 17/945,631 is a continuation of application No. 16/821,099, filed on Mar. 17, 2020, granted, now 11,469,110, issued on Oct. 11, 2022.
Application 16/821,099 is a continuation of application No. 16/265,782, filed on Feb. 1, 2019, granted, now 10,629,451, issued on Apr. 21, 2020.
Prior Publication US 2024/0112920 A1, Apr. 4, 2024
This patent is subject to a terminal disclaimer.
Int. Cl. H01L 21/311 (2006.01); H01L 21/3105 (2006.01); H01L 29/66 (2006.01); H10D 64/01 (2025.01)
CPC H01L 21/31116 (2013.01) [H01L 21/31058 (2013.01); H10D 64/015 (2025.01)] 20 Claims
OG exemplary drawing
 
1. A cyclic etch method, the method comprising the steps of:
i) exposing a SiN layer covering structures on a substrate in a reaction chamber to a plasma of hydrofluorocarbon (HFC) to form a polymer layer deposited on the SiN layer that modifies the surface of the SiN layer, the HFC having a formula CxHyFz where x=2-5, y>z, the HFC being a saturated or unsaturated, linear or cyclic HFC;
ii) exposing the polymer layer deposited on the SiN layer to a plasma of an inert gas, the plasma of the inert gas removing the polymer layer deposited on the SiN layer and the modified surface of the SiN layer on etch front; and
iii) repeating the steps of i) and ii) until the SiN layer covered on the etch front is removed, thereby forming vertical straight SiN spacers with the SiN layer covered on the sidewalls of the structures,
wherein the plasma of the HFC in step i) is a remote plasma.