Selective functionalization of SiO2 and SiNx surfaces is challenging after atmospheric exposure or after exposure to an etching plasma chemistry as both surfaces tend to have similar functional groups. Here, we show that a SiNx surface can be selectively functionalized over SiO2 with benzaldehyde after the first atomic layer etching (ALE) cycle. Similar to our previous work on pristine plasma-deposited SiO2 and SiNx surfaces [R. J. Gasvoda, Z. Zhang, E. A. Hudson, and S. Agarwal, J. Vac. Sci Technol. A 39, 040401 (2021)], this selective functionalization can be used to increase the overall SiO2 to SiNx etch selectivity during ALE. The surface reactions, composition, and film thickness during ALE were monitored using in situ surface infrared spectroscopy and in situ four-wavelength ellipsometry. Our ALE process consisted of alternating cycles of CFx deposition from a C4F6/Ar plasma and an Ar activation plasma with an average ion energy of ∼210 eV. The first ALE cycle removed the surface SiOxNy layer on the SiNx surface and created reactive sites for selective benzaldehyde attachment.
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September 2021
Letter|
July 26 2021
Selective functionalization of partially etched SiNx to enhance SiO2 to SiNx etch selectivity
Ryan J. Gasvoda
;
Ryan J. Gasvoda
a)
1
Department of Chemical and Biological Engineering, Colorado School of Mines
, Golden, Colorado 80401
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Xue Wang;
Xue Wang
1
Department of Chemical and Biological Engineering, Colorado School of Mines
, Golden, Colorado 80401
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Prabhat Kumar;
Prabhat Kumar
2
Lam Research Corporation
, 4650 Cushing Parkway, Fremont, California 94538
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Eric A. Hudson;
Eric A. Hudson
b)
2
Lam Research Corporation
, 4650 Cushing Parkway, Fremont, California 94538
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Sumit Agarwal
Sumit Agarwal
c)
1
Department of Chemical and Biological Engineering, Colorado School of Mines
, Golden, Colorado 80401
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a)
Present address: Lam Research Corporation, 11155 SW Leveton Dr, Tualatin, OR 97062.
b)
Electronic mail: eric.hudson@lamresearch.com
c)
Author to whom correspondence should be addressed: sagarwal@mines.edu
Note: This paper is a part of the Special Topic Collection Celebrating the Early Career Professionals Contributing to the Advancement of Thin Films, Surfaces, Interfaces, and Plasmas.
J. Vac. Sci. Technol. A 39, 050401 (2021)
Article history
Received:
May 02 2021
Accepted:
July 02 2021
Citation
Ryan J. Gasvoda, Xue Wang, Prabhat Kumar, Eric A. Hudson, Sumit Agarwal; Selective functionalization of partially etched SiNx to enhance SiO2 to SiNx etch selectivity. J. Vac. Sci. Technol. A 1 September 2021; 39 (5): 050401. https://doi.org/10.1116/6.0001110
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