AVS 45th International Symposium
    Plasma Science and Technology Division Monday Sessions
       Session PS-MoP

Paper PS-MoP8
An Integrated Surface Kinetics-Plasma Equipment Model for Etching and Deposition: Effects of Bias on Wall Reactions@footnote 1@

Monday, November 2, 1998, 5:30 pm, Room Hall A

Session: Plasma Science and Technology Poster Session
Presenter: D. Zhang, University of Illinois, Urbana-Champaign
Authors: D. Zhang, University of Illinois, Urbana-Champaign
M.J. Kushner, University of Illinois, Urbana-Champaign
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In high plasma density, low pressure etching tools, heavy particle reactions which occur at the walls are equally, if not more important, than heavy particle reactions which occur in the gas phase. To self consistently address these reactions, as well as to address reactions mechanisms occuring on the wafer, a Surface Kinetics Module (SKM) has been developed for the Hybrid Plasma Equipment Model (HPEM). The SKM is a surface site balance model which is employed at every mesh-point at the border between the plasma and surfaces. During each iteration of the HPEM, the fluxes and energies of species from the plasma to selected surfaces are used as input to a set of differential equations encompassing the surface reaction mechanism. The SKM then solves for the steady state values of surface coverages, processing rate (etching or deposition), and the species/fluxes leaving the the surface to the plasma. These values are then used to update the flux-in/flux-out boundary conditions which are used in the plasma portion of the HPEM. The SKM has been employed to investigate reaction mechanisms in Inductively Coupled Plasma (ICP) etching (oxide and poly-Si) systems with an rf biased substrate. With increasing rf biasing, the sheath voltage at surfaces other than the wafer also increase, thereby increasing the rate of sputtering of passivating species. These species return to the plasma, thereby increasing their flux to the wafer. The goal of the investigation is to determine whether the variation of these wall sputtering processes with rf bias amplitude is sufficient to significantly perturb the etching rate on the wafer. @FootnoteText@ @footnote 1@Work supported by SRC and NSF.