Mechanism of SiN etching rate fluctuation in atomic layer etching

Hirata, Akiko; Fukasawa, Masanaga; Kugimiya, Katsuhisa; Nagaoka, Kojiro; Karahashi, Kazuhiro; Hamaguchi, Satoshi; Iwamoto, Hayato

doi:https://doi.org/10.1116/6.0000257

Mechanism of SiN etching rate fluctuation in atomic layer etching

Hirata, Akiko; Fukasawa, Masanaga; Kugimiya, Katsuhisa et al.

Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films, 2020, 38(6), 062601

Number of Access:563（2025-08-14 18:26 Counts）

Identifier to cite or link to this item: https://hdl.handle.net/11094/78454

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Title	Mechanism of SiN etching rate fluctuation in atomic layer etching
Creator	CreatorName Hirata, Akiko
	CreatorName Fukasawa, Masanaga
	CreatorName Kugimiya, Katsuhisa
	CreatorName Nagaoka, Kojiro
	NRID 1000060451118 1000060451118 ORCID 0000-0001-9951-6573 0000-0001-9951-6573 researchmap permalink karahashi karahashi Scopus Author ID 6602275601 6602275601 CreatorName Karahashi, Kazuhiro
	NRID 1000060301826 1000060301826 ORCID 0000-0001-6580-8797 0000-0001-6580-8797 researchmap permalink satoshi_hamaguchi satoshi_hamaguchi Scopus Author ID 55220082400 55220082400 CreatorName Hamaguchi, Satoshi
	CreatorName Iwamoto, Hayato
Description	A. Hirata et al., Journal of Vacuum Science & Technology A 38, 062601 (2020) https://doi.org/10.1116/6.0000257
Abstract	Atomic layer etching (ALE) enables atomic-precision control of the surface reaction for device fabrication. In this study, we investigate SiN ALE with process optimization of the surface adsorption and desorption steps, and we clarify the rate fluctuation mechanism. When we attempted CH3F/Ar plasma adsorption followed by the subsequent Ar desorption step, an etch stop was observed owing to the excess deposition (>6 nm) of a protective film on the surface. X-ray photoelectron spectroscopy analysis revealed that a high number of C-C bonds was detected. As the bonding energy of C-C (6.4 eV) is high, these bonds remain after the desorption step. The excess C-rich polymer deposition after ALE originates from the residual C-C bonds. To suppress the C-rich polymer deposition, we studied stable SiN ALE using a desorption step with Ar/O2 plasma (0.36 nm/cycle) and a two-step sequential desorption with Ar and O2 plasma (0.6 nm/cycle), which resulted in stable SiN ALE processes. Because the surface condition is able to fluctuate with the number of cycles, precise surface control is strongly required to achieve stable ALE. Control of the plasma-wall interaction is also important for stable SiN ALE. We intentionally changed the chamber wall conditions and found that the polymer-deposited wall caused a fluctuation of the etched amount, which resulted from CFx desorption from the deposited polymer. Thus, it is also important to control the influence of desorbed species from the chamber components for suppression of the ALE fluctuation.
Publisher	American Institute of Physics
Source Title	Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films
Volume (Issue)	38(6)
Page	062601
Date of Issued	2020-12
Language	English
Handle URL	https://hdl.handle.net/11094/78454
PISSN	07342101
eISSN	15208559
NCID	AA10635514
Relation.isIdenticalTo	DOI (Publisher Version) https://doi.org/10.1116/6.0000257
Access Rights	open access
CopyRight	This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Journal of Vacuum Science & Technology A 38, 062601 (2020) and may be found at https://doi.org/10.1116/6.0000257.
oaire:version	Version of Record
Category	学術雑誌論文 Journal Article

Resource Type	journal article
Local Type	Journal Article
DCTERMS.bibliographicCitation	Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films. 2020, 38(6), p. 062601
DC.title	Mechanism of SiN etching rate fluctuation in atomic layer etching
DC.creator	Hirata, Akiko
	Fukasawa, Masanaga
	Kugimiya, Katsuhisa
	Nagaoka, Kojiro
	Karahashi, Kazuhiro
	Hamaguchi, Satoshi
	Iwamoto, Hayato
DC.publisher	American Institute of Physics
DC.language' scheme='DCTERMS.RFC1766	English
DCTERMS.issued' scheme='DCTERMS.W3CDTF	2020-12
DC.identifier	https://doi.org/10.1116/6.0000257
DC.description	A. Hirata et al., Journal of Vacuum Science & Technology A 38, 062601 (2020) https://doi.org/10.1116/6.0000257
DCTERMS.abstract	Atomic layer etching (ALE) enables atomic-precision control of the surface reaction for device fabrication. In this study, we investigate SiN ALE with process optimization of the surface adsorption and desorption steps, and we clarify the rate fluctuation mechanism. When we attempted CH3F/Ar plasma adsorption followed by the subsequent Ar desorption step, an etch stop was observed owing to the excess deposition (>6 nm) of a protective film on the surface. X-ray photoelectron spectroscopy analysis revealed that a high number of C-C bonds was detected. As the bonding energy of C-C (6.4 eV) is high, these bonds remain after the desorption step. The excess C-rich polymer deposition after ALE originates from the residual C-C bonds. To suppress the C-rich polymer deposition, we studied stable SiN ALE using a desorption step with Ar/O2 plasma (0.36 nm/cycle) and a two-step sequential desorption with Ar and O2 plasma (0.6 nm/cycle), which resulted in stable SiN ALE processes. Because the surface condition is able to fluctuate with the number of cycles, precise surface control is strongly required to achieve stable ALE. Control of the plasma-wall interaction is also important for stable SiN ALE. We intentionally changed the chamber wall conditions and found that the polymer-deposited wall caused a fluctuation of the etched amount, which resulted from CFx desorption from the deposited polymer. Thus, it is also important to control the influence of desorbed species from the chamber components for suppression of the ALE fluctuation.
DC.rights	This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Journal of Vacuum Science & Technology A 38, 062601 (2020) and may be found at https://doi.org/10.1116/6.0000257.
DC.format	78454
citation_title	Mechanism of SiN etching rate fluctuation in atomic layer etching
citation_author	Hirata, Akiko
	Fukasawa, Masanaga
	Kugimiya, Katsuhisa
	Nagaoka, Kojiro
	Karahashi, Kazuhiro
	Hamaguchi, Satoshi
	Iwamoto, Hayato
citation_publisher	American Institute of Physics
citation_language	English
citation_date	2020-12
citation_journal_title	Journal of Vacuum Science and Technology A: Vacuum, Surfaces and Films
citation_volume	38
citation_issue	6
citation_firstpage	062601
citation_doi	https://doi.org/10.1116/6.0000257
citation_public_url	https://hdl.handle.net/11094/78454

Mechanism of SiN etching rate fluctuation in atomic layer etching

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