In situ ellipsometry study of atomic hydrogen etching of extreme ultraviolet induced carbon layers

TitleIn situ ellipsometry study of atomic hydrogen etching of extreme ultraviolet induced carbon layers
Publication TypeJournal Article
Year of Publication2011
AuthorsJ.Q Chen, E. Louis, R. Harmsen, T. Tsarfati, H. Wormeester, M. van Kampen, W. van Schaik, R. van de Kruijs, F. Bijkerk
JournalApplied Surface Science
Volume258
Issue1
Pagination7-12
Date PublishedOct
Type of ArticleArticle
ISBN Number0169-4332
KeywordsAMORPHOUS-CARBON, Atomic hydrogen etching, contamination, ellipsometry, EUV-induced carbon contamination, EXPOSURE, films, GROWTH, MITIGATION, MULTILAYER MIRRORS, OPTICS, RADIATION, SURFACES
Abstract

Atomic hydrogen based etching is generally considered an efficient method for the removal of carbon films resulting from photo-induced hydrocarbon dissociation, as occurs in extreme ultraviolet (EUV) photolithography environments. The etch rate of atomic hydrogen for three different kinds of carbon films was determined, namely for EUV-induced carbon, hot filament evaporated carbon and e-beam evaporated carbon. The etching process was monitored in situ by spectroscopic ellipsometry. The etch rate was found to depend on the type of carbon (polymer or graphite-like), on the layer thickness, and on the temperature. The EUV-induced carbon shows the highest etch rate, with a value of similar to 0.2 nm/min at a sample temperature of 60 degrees C. The more graphite-like carbon layers showed an etch rate that was about 10 times lower at this temperature. An activation energy of 0.45 eV was found for etching of the EUV-induced carbon layer. (C) 2011 Elsevier B. V. All rights reserved.

DOI10.1016/j.apsusc.2011.07.121
Division

nSI

PID

3a4ef3043fe5dbb0457ee1a16db4ac23

Alternate TitleAppl. Surf. Sci.

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