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Proceedings Paper

Dependence of contamination rates on key parameters in EUV optics
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Paper Abstract

Optics contamination remains one of the challenges in extreme ultraviolet (EUV) lithography. Dependence of contamination rates on key EUV parameters was investigated. EUV tools have optics at different illumination angles. It was observed that at shallower angles, the carbon contamination rate and surface roughness was higher on the optics surface. This is a concern in EUV optics as higher roughness would increase the scattering of the EUV radiation. Secondary ion time of flight mass spectrometer (TOF-SIMS) data indicated that the carbon contamination film might be a polymer. Three chemical species were used to investigate the dependence of polymerization and reactivity on the contamination rate. Acrylic acid was found to have a measurable contamination rate above background compared to propionic acid and methyl methacrylate. Secondary electron dissociation is one of the mechanisms considered to be a cause for the growth of the carbon contamination film. Multiple experiments with two substrates having different secondary electron yields were performed. The substrate with the higher secondary electron yield was found to give a higher contamination rate.

Paper Details

Date Published: 8 April 2011
PDF: 8 pages
Proc. SPIE 7969, Extreme Ultraviolet (EUV) Lithography II, 796923 (8 April 2011); doi: 10.1117/12.879491
Show Author Affiliations
Yashdeep Khopkar, Univ. at Albany (United States)
Petros Thomas, Univ. at Albany (United States)
Leonid Yankulin, Univ. at Albany (United States)
Rashi Garg, Univ. at Albany (United States)
Chimaobi Mbanaso, Univ. at Albany (United States)
Alin Antohe, Univ. at Albany (United States)
Mihir Upadhyaya, Univ. at Albany (United States)
Vimal Kumar Kamineni, Univ. at Albany (United States)
Yu-Jen Fan, Univ. at Albany (United States)
Gregory Denbeaux, Univ. at Albany (United States)
Vibhu Jindal, SEMATECH (United States)
Andrea Wüest, SEMATECH (United States)
Eric Gullikson, Lawrence Berkeley National Lab. (United States)

Published in SPIE Proceedings Vol. 7969:
Extreme Ultraviolet (EUV) Lithography II
Bruno M. La Fontaine; Patrick P. Naulleau, Editor(s)

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