AVS 50th International Symposium
    Plasma Science and Technology Wednesday Sessions
       Session PS1-WeA

Paper PS1-WeA6
IRIS Investigations of Gas Phase Species in Fluorocarbon Plasmas

Wednesday, November 5, 2003, 3:40 pm, Room 314

Session: Mechanisms in Plasma-Surface Interactions
Presenter: I.T. Martin, Colorado State University
Authors: I.T. Martin, Colorado State University
E.R. Fisher, Colorado State University
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Fluorocarbon (FC) plasmas are widely used for FC film deposition and the etching of Si-based materials. Investigating a specific molecule during plasma processing of a substrate can yield information on its role in the chemistry occuring at the plasma surface interface. CF@sub 2@ is a particularly interesting species in FC plasmas because its role differs in various plasma systems. CF@sub x@ and C@sub x@F@sub y@ radicals have been cited as FC film deposition precursors, while other work has shown cases where CF@sub 2@ is not a deposition precursor.@footnote 1,2,3@ We have used our imaging of radicals interacting with surfaces (IRIS) method to measure the surface interactions of CF@sub 2@ radicals with Si substrates during plasma processing. CF@sub 2@ surface loss coefficients determined for 25-200W C@sub 3@F@sub 8@ and C@sub 4@F@sub 8@ plasmas show relatively high levels of scattering, which indicates that CF@sub 2@ radicals are produced at the surface in these systems. One advantage of the IRIS system is our ability to collect data for multiple molecules in a single plasma system. Experimental excitation spectra have verified the presence of CF in our FC systems and have been used to determine the rotational temperatures (@theta@@sub R@) of CF in the plasmas. Trends in @theta@@sub R@ are discussed as a function of plasma input power and source gas. Surface reactivity studies will determine if CF contributes to CF@sub 2@ scatter in these systems. Preliminary investigations of SiF@sub 2@(g) formation at the surface will also be presented. @FootnoteText@ @footnote 1@ R. d'Agostino, et al., in Plasma Deposition, Treatment, and Etching of Fluorocarbons, edited by R. d'Agostino (Academic Press, Inc., San Diego, 1990) p.95-143.@footnote 2@ S. Samukawa, AIP Conference Proceedings 636, 95-107 (2002).@footnote 3@ K. Sasaki, et al., Thin Solid Films 374(2), 249-255 (2000).