Self-limiting processes in thermal atomic layer etching of nickel by hexafluoroacetylacetone

Basher, Abdulrahman H.; Hamada, Ikutaro; Hamaguchi, Satoshi

doi:10.35848/1347-4065/aba9a7

Cited by 9 publications

(8 citation statements)

References 33 publications

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“…[46] This temperature is also significantly lower than those used for other dry etching processes, e.g., etching of ZrO 2 and Al 2 O 3 , which are typically in excess of 250 °C. [47] Based on etching reactions of hfacH with NiO proposed by Basher [48] and ZnO proposed by Kung and Teplyakov, [49] a reaction scheme for hfacH etching of aZnMIm is proposed in Scheme 2 and expressed in Figure 3a. In the etching of metal oxides, adsorption of hfacH with a proton transfer to oxygen in the metal oxide is followed by desorption of a metal hfac complex and water.…”

Section: Etching Of Aznmim Films By Hfachmentioning

confidence: 99%

Zinc‐Imidazolate Films as an All‐Dry Resist Technology

Corkery,

Waltz,

Eckhert

et al. 2023

Adv Funct Materials

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Motivated by the drawbacks of solution phase processing, an all‐dry resist formation process is presented that utilizes amorphous zinc‐imidazolate (aZnMIm) films deposited by atomic/molecular layer deposition (ALD/MLD), patterned with electron beam lithography (EBL), and developed by novel low temperature (120 °C) gas phase etching using 1,1,1,5,5,5‐hexafluoroacetylacetone (hfacH) to achieve well‐resolved 22 nm lines with a pitch of 30 nm. The effects of electron beam irradiation on the chemical structure and hfacH etch resistance of aZnMIm films are investigated, and it is found that electron irradiation degrades the 2‐methylimidazolate ligands and transforms aZnMIm into a more dense material that is resistant to etching by hfacH and has a C:N:Zn ratio effectively identical to that of unmodified aZnMIm. These findings showcase the potential for aZnMIm films to function in a dry resist technology. Sensitivity, contrast, and critical dimensions of the patterns are determined to be 37 mC cm−2, 0.87, and 29 nm, respectively, for aZnMIm deposited on silicon substrates and patterned at 30 keV. This work introduces a new direction for solvent‐free resist processing, offering the prospect of scalable, high‐resolution patterning techniques for advanced semiconductor fabrication processes.

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Section: Etching Of Aznmim Films By Hfachmentioning

confidence: 99%

Zinc‐Imidazolate Films as an All‐Dry Resist Technology

Corkery,

Waltz,

Eckhert

et al. 2023

Adv Funct Materials

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“…For ALE of metal and metal oxides, various isotropic ALE has been proposed and studied. Metal oxides can be etched with ligand exchange reactions [22,[158][159][160] or the formation of metal complexes with gaseous organic molecules [161][162][163][164][165][166][167][168]. If plasmas are used in at least one of the half-cycles of such isotropic ALE process, the process may be called (radical-driven) PE-ALE [169,170].…”

Section: Ale Of Metals Metal Oxides and Metal Nitridesmentioning

confidence: 99%

Foundations of atomic-level plasma processing in nanoelectronics

Arts

Hamaguchi²,

Ito³

et al. 2022

Plasma Sources Sci. Technol.

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This article discusses key elementary surface-reaction processes in state-of-the-art plasma etching and deposition relevant to the nanoelectronic device fabrication and presents a concise guide to the forefront of research on plasma-enhanced atomic layer etching (PE-ALE) and plasma-enhanced atomic layer deposition (PE-ALD). As the critical dimensions of semiconductor devices approach the atomic scale, atomic-level precision is required in plasma processing. The development of advanced plasma processes with such accuracy necessitates an in-depth understanding of the surface reaction mechanisms. With this in mind, we first review the basics of reactive ion etching (RIE) and high-aspect aspect-ratio (HAR) etching and we elaborate on the methods of PE-ALE and PE-ALD as surface-controlled processing, as opposed to the conventional flux-controlled processing such as RIE and chemical vapor deposition (CVD). Second, we discuss the surface reaction mechanisms of PE-ALE and PE-ALD and the roles played by incident ions and radicals for in their reactions. More specifically, we discuss the role of transport of ions and radicals, including their surface reaction probabilities and ion-energy-dependent threshold effects in processing over HAR features such as deep holes and trenches.

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“…9,35,[65][66][67] Thermal ALE, which uses thermal chemical reactions, rather than ion irradiation, in the desorption step, can avoid surface damage induced by ion impact. 12,[68][69][70][71][72][73][74] On the other hand, thermal ALE processes typically lead to isotropic etch, i.e. etching that proceeds in the surface normal direction.…”

Section: Introductionmentioning

confidence: 99%

Five-step plasma-enhanced atomic layer etching of silicon nitride with a stable etched amount per cycle

Hirata

Fukasawa

Tercero

et al. 2022

Jpn. J. Appl. Phys.

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Atomic layer etching is an advanced plasma etching technique that enables the atomic-precision control. In this study, the effects of surface conditions on the stability of the etched amount per cycle (EPC) in silicon nitride (SiN) plasma-enhanced atomic layer etching (PE-ALE) were examined. A single cycle of SiN PE-ALE consisted of two steps: hydrofluorocarbon (HFC) absorption step and argon-ion (Ar+) desorption step. After a few cycles, an etch-stop of SiN occurred due to the HFC deposition. An oxygen-plasma ashing step was introduced after desorption step, which made three-step SiN PE-ALE. The etch-stop was avoided but the EPC was low due to the surface oxidation of SiN. By combining this three-step SiN PE-ALE with subsequent two-step SiO2 PE-ALE, which consists of fluorocarbon adsorption step and Ar+ desorption step, SiN PE-ALE was achieved with a stable and large EPC. This five-step SiN PE-ALE allows the precise control of SiN etched depth.

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Self-limiting processes in thermal atomic layer etching of nickel by hexafluoroacetylacetone

Cited by 9 publications

References 33 publications

Zinc‐Imidazolate Films as an All‐Dry Resist Technology

Zinc‐Imidazolate Films as an All‐Dry Resist Technology

Foundations of atomic-level plasma processing in nanoelectronics

Five-step plasma-enhanced atomic layer etching of silicon nitride with a stable etched amount per cycle

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