Highly selective etch gas chemistry design for precise DSAL dry development process

M. Omura; T. Imamura; H. Yamamoto; I. Sakai; H. Hayashi

doi:10.1117/12.2046145

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28 March 2014 Highly selective etch gas chemistry design for precise DSAL dry development process

M. Omura, T. Imamura, H. Yamamoto, I. Sakai, H. Hayashi

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Proceedings Volume 9054, Advanced Etch Technology for Nanopatterning III; 905409 (2014) https://doi.org/10.1117/12.2046145
Event: SPIE Advanced Lithography, 2014, San Jose, California, United States

Abstract

Dry development process for directed-self assembly lithography (DSAL) hole shrink process has been studied with focus on etch selectivity of poly(methyl methacrylate) (PMMA) to polystyrene (PS) and suppression of etch stop. Highly selective etch of PMMA to PS was achieved using CO gas chemistry. However, it was found that PMMA etching stopped proceeding beyond a certain depth. Scanning Transmission Electron Microscopy (STEM) and X-ray Photoelectron Spectroscopy (XPS) analysis indicated that a deposition layer formed not only on PS but also on PMMA. H₂ addition to CO plasma proved effective in controlling the deposition layer thickness and suppressing etch stop. CO/H₂ plasma process combined with ion energy control was applied to the dry development process for hole shrink. DSAL dry development process for hole shrink process was successfully realized by designing the etch gas chemistry and controlling ion energy.

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M. Omura, T. Imamura, H. Yamamoto, I. Sakai, and H. Hayashi "Highly selective etch gas chemistry design for precise DSAL dry development process", Proc. SPIE 9054, Advanced Etch Technology for Nanopatterning III, 905409 (28 March 2014); https://doi.org/10.1117/12.2046145

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