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Proceedings Paper

Analysis and characterization of contamination in EUV reticles
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Paper Abstract

A host of complementary imaging techniques (Scanning Electron Microscopy), surface analytical technique (Auger Electron Spectroscopy, AES), chemical analytical and speciation techniques (Grazing Incidence Reflectance Fourier-Transform Infrared Spectroscopy, GIR-FTIR; and Raman spectroscopy) have been assessed for their sensitivity and effectiveness in analyzing contamination on three EUV reticles that were contaminated to varying degrees. The first reticle was contaminated as a result of its exposure experience on the SEMATECH EUV Micro Exposure Tool (MET) at Lawrence Berkeley National Laboratories, where it was exposed to up to 80 hours of EUV radiation. The second reticle was a full-field reticle, specifically designed to monitor molecular contamination, and exposed to greater than 1600J/cm2 of EUV radiation on the ASML Alpha Demo Tool (ADT) in Albany Nanotech in New York. The third reticle was intentionally contaminated with hydrocarbons in the Microscope for Mask Imaging and Contamination Studies (MIMICS) tool at the College of Nanoscale Sciences of State University of New York at Albany. The EUV reflectivities of some of these reticles were measured on the Advanced Light Source EUV Reflectomer at Lawrence Berkeley National Laboratories and PTB Bessy in Berlin, respectively. Analysis and characterization of thin film contaminants on the two EUV reticles exposed to varying degrees of EUV radiation in both MET and ADT confirm that the two most common contamination types are carbonization and surface oxidation, mostly on the exposed areas of the reticle, and with the MET being significantly more susceptible to carbon contamination than the ADT. While AES in both surface scanning and sputter mode is sensitive and efficient in analyzing thin contaminant films (of a few nanometers), GIRFTIR is sensitive to thick films (of order of a 100 nm or more on non-infra-red reflecting substrates), Raman spectroscopy is not compatible with analyzing such contaminants because of laser-induced evaporation of the contaminant film. SEM and EUV reflectometry are effective in quantifying the impact of contamination on imaging performance and reflectivity, respectively.

Paper Details

Date Published: 22 March 2010
PDF: 13 pages
Proc. SPIE 7636, Extreme Ultraviolet (EUV) Lithography, 76361Y (22 March 2010); doi: 10.1117/12.847269
Show Author Affiliations
Uzodinma Okoroanyanwu, GLOBALFOUNDRIES Inc. (United States)
Kornelia Dittmar, GLOBALFOUNDRIES Inc. (Germany)
Torsten Fahr, GLOBALFOUNDRIES Inc. (Germany)
Tom Wallow, GLOBALFOUNDRIES Inc. (United States)
Bruno La Fontaine, GLOBALFOUNDRIES Inc. (United States)
Obert Wood, GLOBALFOUNDRIES Inc. (United States)
Christian Holfeld, GLOBALFOUNDRIES Inc. (Germany)
Karsten Bubke, GLOBALFOUNDRIES Inc. (Germany)
Jan-Hendrik Peters, Advanced Mask Technology Ctr. GmbH Co. KG (Germany)

Published in SPIE Proceedings Vol. 7636:
Extreme Ultraviolet (EUV) Lithography
Bruno M. La Fontaine, Editor(s)

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