AVS 46th International Symposium
    Manufacturing Science and Technology Group Thursday Sessions
       Session MS+PS-ThM

Paper MS+PS-ThM7
PFC Abatement in Inductively Coupled Plasma Reactors using O@sub 2@, H@sub 2@ and H@sub 2@O as Additive Gases@footnote 1@

Thursday, October 28, 1999, 10:20 am, Room 611

Session: Environmentally Benign Manufacturing
Presenter: X. Xu, University of Illinois, Urbana
Authors: X. Xu, University of Illinois, Urbana
M.J. Kushner, University of Illinois, Urbana
Correspondent: Click to Email
Perfluorinated compounds (PFCs), gases which have large global warming potentials, are widely used in plasma processing for etching and chamber cleaning. Due to under-utilization of the feedstock gases or by-product generation, it is usually necessary to abate emissions of PFCs from plasma processing reactors. Plasma abatement is being developed as one remediation strategy. Previous studies have shown that plasma abatement of, for example, C@sub 2@F@sub 6@ using O@sub 2@ as an additive may be effective in remediating the C@sub 2@F@sub 6@ but may also generate PFC products such as CF@sub 4@. Alternate additive gases may, however, avoid this problem. In this study, the scaling of plasma abatement is investigated using the 2-dimensional Hybrid Plasma Equipment Model (HPEM). Both the plasma etching chamber and downstream plasma burn-box are simulated in order to have realistic entry conditions for the burn-box. O@sub 2@, H@sub 2@, and H@sub 2@O are examined as additive gases in the burn-box. All PFCs in the effluent can generally be remediated in the burn-box at high power deposition with a sufficiently large flow of additive gases. In general CF@sub 4@ generation occurs during abatement of C@sub 2@F@sub 6@ using O@sub 2@ as an additive. CF@sub 4@ is not, however, substantially produced when H@sub 2@ or H@sub 2@O are used as additives due to the consumption of free fluorine by H, OH and H@sub 2@. The end products are dominated by COF@sub x@ with O@sub 2@ and by HF with H@sub 2@. The efficiency of PFC abatement (as measured by eV/molecule abated) decreases with increasing power and decreasing additive mole fraction. @FootnoteText@ @footnote 1@This work was supported by SRC and Applied Materials.