|Title||In situ ellipsometry study of atomic hydrogen etching of extreme ultraviolet induced carbon layers|
|Publication Type||Journal Article|
|Year of Publication||2011|
|Authors||J.Q Chen, E. Louis, R. Harmsen, T. Tsarfati, H. Wormeester, M. van Kampen, W. van Schaik, R. van de Kruijs, F. Bijkerk|
|Journal||Applied Surface Science|
|Type of Article||Article|
|Keywords||AMORPHOUS-CARBON, Atomic hydrogen etching, contamination, ellipsometry, EUV-induced carbon contamination, EXPOSURE, films, GROWTH, MITIGATION, MULTILAYER MIRRORS, OPTICS, RADIATION, SURFACES|
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.
|Alternate Title||Appl. Surf. Sci.|
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