skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Simplified calculation of nonlocal thermodynamic equilibrium excited state populations contributing to 13.5 nm emission in a tin plasma

Abstract

Extreme ultraviolet lithography schemes for the semiconductor industry are currently based on coupling radiation from a plasma source into a 2% bandwidth at 13.5 nm (91.8 eV). In this paper, we consider the case for a laser-produced plasma (LPP) and address the calculation of ionic level populations in the 4p{sup 6}4d{sup N}, 4p{sup 6}4d{sup N-1}4f{sup 1}, 4p{sup 5}4d{sup N+1}, and 4p{sup 6}4d{sup N-1}5p{sup 1} configurations in a range of tin ions (Sn{sup 6+} to Sn{sup 13+}) producing radiation in this bandwidth. The LPP is modeled using a one-dimensional hydrodynamics code, which uses a hydrogenic, average atom model, where the level populations are treated as l degenerate. Hartree-Fock calculations are used to remove the l degeneracy and an energy functional method to calculate the nl level populations involved in n=4-4 transitions as a function of distance from the target surface and time. Detailed data are presented for the tin ions that contribute to in-band emission.

Authors:
; ; ; ;  [1]
  1. School of Physics, University College Dublin, Belfield, Dublin 4 (Ireland)
Publication Date:
OSTI Identifier:
20982696
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 101; Journal Issue: 4; Other Information: DOI: 10.1063/1.2434965; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; EQUILIBRIUM; EXCITED STATES; EXTREME ULTRAVIOLET RADIATION; HARTREE-FOCK METHOD; HYDRODYNAMICS; LASER-PRODUCED PLASMA; MULTICHARGED IONS; ONE-DIMENSIONAL CALCULATIONS; PLASMA PRODUCTION; SEMICONDUCTOR MATERIALS; THERMODYNAMICS; TIN; TIN IONS

Citation Formats

White, J., Cummings, A., Dunne, P., Hayden, P., and O'Sullivan, G. Simplified calculation of nonlocal thermodynamic equilibrium excited state populations contributing to 13.5 nm emission in a tin plasma. United States: N. p., 2007. Web. doi:10.1063/1.2434965.
White, J., Cummings, A., Dunne, P., Hayden, P., & O'Sullivan, G. Simplified calculation of nonlocal thermodynamic equilibrium excited state populations contributing to 13.5 nm emission in a tin plasma. United States. doi:10.1063/1.2434965.
White, J., Cummings, A., Dunne, P., Hayden, P., and O'Sullivan, G. Thu . "Simplified calculation of nonlocal thermodynamic equilibrium excited state populations contributing to 13.5 nm emission in a tin plasma". United States. doi:10.1063/1.2434965.
@article{osti_20982696,
title = {Simplified calculation of nonlocal thermodynamic equilibrium excited state populations contributing to 13.5 nm emission in a tin plasma},
author = {White, J. and Cummings, A. and Dunne, P. and Hayden, P. and O'Sullivan, G.},
abstractNote = {Extreme ultraviolet lithography schemes for the semiconductor industry are currently based on coupling radiation from a plasma source into a 2% bandwidth at 13.5 nm (91.8 eV). In this paper, we consider the case for a laser-produced plasma (LPP) and address the calculation of ionic level populations in the 4p{sup 6}4d{sup N}, 4p{sup 6}4d{sup N-1}4f{sup 1}, 4p{sup 5}4d{sup N+1}, and 4p{sup 6}4d{sup N-1}5p{sup 1} configurations in a range of tin ions (Sn{sup 6+} to Sn{sup 13+}) producing radiation in this bandwidth. The LPP is modeled using a one-dimensional hydrodynamics code, which uses a hydrogenic, average atom model, where the level populations are treated as l degenerate. Hartree-Fock calculations are used to remove the l degeneracy and an energy functional method to calculate the nl level populations involved in n=4-4 transitions as a function of distance from the target surface and time. Detailed data are presented for the tin ions that contribute to in-band emission.},
doi = {10.1063/1.2434965},
journal = {Journal of Applied Physics},
number = 4,
volume = 101,
place = {United States},
year = {Thu Feb 15 00:00:00 EST 2007},
month = {Thu Feb 15 00:00:00 EST 2007}
}