Actions for Ion and Neutral Species in C(2)F(6) and CHF(3) Dielectric Etch Discharges [electronic resource].

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Ion and Neutral Species in C(2)F(6) and CHF(3) Dielectric Etch Discharges [electronic resource].

Published
Washington, D.C. : United States. Dept. of Energy, 1999.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
Additional Creators
Sandia National Laboratories, United States. Department of Energy, and United States. Department of Energy. Office of Scientific and Technical Information
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Summary
Relative concentrations of reactive ions, neutral radicals, resist and substrate etch products have been measured in dielectric etch chemistries using an uncollided beam mass spectrometer / ion extractor from Hiden Analytical. Analysis techniques employed include both electron impact ionization and dissociative ionization of neutral gas, and potential bias extraction of positive ions from the reactor discharge volume. Measurements were made in C₂F₆ and CHF₃ discharges in an inductively coupled plasma (ICP-GEC) research reactor operating with power densities, pressures, gas compositions and wafer materials typical of those found in etch processing tools. Wafer substrates investigated included blanket silicon wafers and silicon wafers with varying amounts of photo-resist coverage of the surface (20%, 80% and 100%). In C₂F₆ discharges CF₃⁺ was consistently the dominant fluorocarbon ion present, in agreement with published cross sections for dissociative ionization [ 1,2.3,4.5,6]. Smaller concentrations of CF+, CF₂⁻, and C₂F₅⁺, were also observed, though the dissociative ionization production of C₂F₅⁺ was a factor of five smaller than would be expected from published cross section values. The presence of photo-resist, even in small amounts, was found to produce marked changes in the discharge composition. For example in C₂F₆ discharges, concentrations of SiFₓ etch products relative to concentrations of CₓF{sub y} species were notably diminished and larger concentrations of water vapor were observed when resist was present. In CHF₃ discharges, CF₃⁺ and CHF₂⁺ were found to be the main species present, along with smaller concentrations of CF₂⁺, CF⁺, CHF⁺, CH⁺ and F⁻.
Report Numbers
E 1.99:sand99-0172j
sand99-0172j
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Note
Published through SciTech Connect.
01/26/1999.
"sand99-0172j"
"DE00003221"
Journal Vacuum Science and Technology FT
McGrath, R.T.; Hebner, G.; Jayaraman, R.P.
Funding Information
AC04-94AL85000
View MARC record | catkey: 14451345