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Title: Critical parameters influencing the EUV-induced damage of Ru-capped multilayer mirrors

Abstract

Ongoing endurance testing of Ru-capped multilayer mirrors (MLMs) at the NIST synchrotron facility has revealed that the damage resulting from EUV irradiation does not always depend on the exposure conditions in an intuitive way. Previous exposures of Ru-capped MLMs to EUV radiation in the presence of water vapor demonstrated that the mirror damage rate actually decreases with increasing water pressure. We will present results of recent exposures showing that the reduction in damage for partial pressures of water up to 5 x 10{sup -6} Torr is not the result of a spatially uniform decrease in damage across the Gaussian intensity distribution of the incident EUV beam. Instead we observe a drop in the damage rate in the center of the exposure spot where the intensity is greatest, while the reflectivity loss in the wings of the intensity distribution appears to be independent of water partial pressure. (See Fig. 1.) We will discuss how the overall damage rate and spatial profile can be influenced by admixtures of carbon-containing species (e.g., CO, CO{sub 2}, C{sub 6}H{sub 6}) at partial pressures one-to-two orders of magnitude lower than the water vapor partial pressure. An investigation is underway to find the cause of the non-Gaussianmore » damage profile. Preliminary results and hypotheses will be discussed. In addition to high-resolution reflectometry of the EUV-exposure sites, the results of surface analysis such as XPS will be presented. We will also discuss how the bandwidth and time structure of incident EUV radiation may affect the rate of reflectivity degradation. Although the observations presented here are based on exposures of Ru-capped MLMs, unless novel capping layers are similarly characterized, direct application of accelerated testing results could significantly overestimate mirror lifetime in the production environment.« less

Authors:
; ; ; ; ; ; ;
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
902623
Report Number(s):
UCRL-CONF-229030
Journal ID: ISSN 0277-786X; TRN: US0702955
DOE Contract Number:  
W-7405-ENG-48
Resource Type:
Conference
Resource Relation:
Journal Volume: 6517; Conference: Presented at: SPIE Advanced Lithography, San Jose, CA, United States, Feb 25 - Mar 02, 2007
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 71 CLASSICAL AND QUANTUMM MECHANICS, GENERAL PHYSICS; DISTRIBUTION; IRRADIATION; LIFETIME; MIRRORS; PARTIAL PRESSURE; PRODUCTION; RADIATIONS; REFLECTIVITY; SYNCHROTRONS; TESTING; WATER; WATER VAPOR; X-RAY PHOTOELECTRON SPECTROSCOPY

Citation Formats

Hill, S B, Ermanoski, I, Tarrio, C, Lucatorto, T B, Madey, T E, Bajt, S, Fang, M, and Chandhok, M. Critical parameters influencing the EUV-induced damage of Ru-capped multilayer mirrors. United States: N. p., 2007. Web. doi:10.1117/12.712286.
Hill, S B, Ermanoski, I, Tarrio, C, Lucatorto, T B, Madey, T E, Bajt, S, Fang, M, & Chandhok, M. Critical parameters influencing the EUV-induced damage of Ru-capped multilayer mirrors. United States. doi:10.1117/12.712286.
Hill, S B, Ermanoski, I, Tarrio, C, Lucatorto, T B, Madey, T E, Bajt, S, Fang, M, and Chandhok, M. Mon . "Critical parameters influencing the EUV-induced damage of Ru-capped multilayer mirrors". United States. doi:10.1117/12.712286. https://www.osti.gov/servlets/purl/902623.
@article{osti_902623,
title = {Critical parameters influencing the EUV-induced damage of Ru-capped multilayer mirrors},
author = {Hill, S B and Ermanoski, I and Tarrio, C and Lucatorto, T B and Madey, T E and Bajt, S and Fang, M and Chandhok, M},
abstractNote = {Ongoing endurance testing of Ru-capped multilayer mirrors (MLMs) at the NIST synchrotron facility has revealed that the damage resulting from EUV irradiation does not always depend on the exposure conditions in an intuitive way. Previous exposures of Ru-capped MLMs to EUV radiation in the presence of water vapor demonstrated that the mirror damage rate actually decreases with increasing water pressure. We will present results of recent exposures showing that the reduction in damage for partial pressures of water up to 5 x 10{sup -6} Torr is not the result of a spatially uniform decrease in damage across the Gaussian intensity distribution of the incident EUV beam. Instead we observe a drop in the damage rate in the center of the exposure spot where the intensity is greatest, while the reflectivity loss in the wings of the intensity distribution appears to be independent of water partial pressure. (See Fig. 1.) We will discuss how the overall damage rate and spatial profile can be influenced by admixtures of carbon-containing species (e.g., CO, CO{sub 2}, C{sub 6}H{sub 6}) at partial pressures one-to-two orders of magnitude lower than the water vapor partial pressure. An investigation is underway to find the cause of the non-Gaussian damage profile. Preliminary results and hypotheses will be discussed. In addition to high-resolution reflectometry of the EUV-exposure sites, the results of surface analysis such as XPS will be presented. We will also discuss how the bandwidth and time structure of incident EUV radiation may affect the rate of reflectivity degradation. Although the observations presented here are based on exposures of Ru-capped MLMs, unless novel capping layers are similarly characterized, direct application of accelerated testing results could significantly overestimate mirror lifetime in the production environment.},
doi = {10.1117/12.712286},
journal = {},
number = ,
volume = 6517,
place = {United States},
year = {Mon Mar 12 00:00:00 EDT 2007},
month = {Mon Mar 12 00:00:00 EDT 2007}
}

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