Dry Etching of Cr2O3/Cr Stacked Film during Resist Ashing by Oxygen Plasma

Autor:	Junichi Tonotani, Shun-ichiro Ohmi, Hiroshi Iwai
Rok vydání:	2005
Předmět:	Materials science General Engineering Analytical chemistry General Physics and Astronomy chemistry.chemical_element Plasma Oxygen Chromium chemistry Ashing Resist Dry etching Photomask Lithography
Zdroj:	Japanese Journal of Applied Physics. 44:114
ISSN:	1347-4065 0021-4922
DOI:	10.1143/jjap.44.114
Popis:	Stacked films of chromium oxide and chromium (Cr2O3/Cr) have been commonly used as a photomask for the lithographic process of integrated circuit fabrication. It has been found, however, that the Cr2O3/Cr films were etched during the oxygen plasma ashing process, which is applied for the resist removal after the Cr2O3/Cr patterning. In order to solve this problem, we investigated the mechanisms of the Cr2O3/Cr film etching during the ashing process. As a result, it was found that the Cr2O3/Cr film is oxidized during the ashing process to generate CrO x (2≤x≤3) in which Cr has a higher valence than Cr2O3, and that the CrO x (2≤x≤3) evaporates. It was confirmed by means of a plasma shielding experiment that not only oxygen plasma but also oxygen radicals oxidize the Cr2O3/Cr. It has been found that keeping the photomask temperature below 200°C during the ashing process solves the Cr2O3/Cr etching problem.
Databáze:	OpenAIRE
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