AVS 49th International Symposium
    Plasma Science Wednesday Sessions
       Session PS+TF-WeP

Paper PS+TF-WeP14
Feature Profile Evolution during Cl@sub 2@ and HBr Plasma Etching of Silicon

Wednesday, November 6, 2002, 11:00 am, Room Exhibit Hall B2

Session: Plasma Etching & Deposition
Presenter: Y.H. Im, Rensselaer Polytechnic Institute
Authors: M.O. Bloomfield, Rensselaer Polytechnic Institute
T.S. Cale, Rensselaer Polytechnic Institute
Y.H. Im, Rensselaer Polytechnic Institute
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As demands for improved IC manufacturing continue to increase, topography simulation of the plasma etching process can help engineers develop easier and less costly process recipes. One of the barriers in achieving this goal is the lack of fundamental understanding of the behavior of energetic ions and reactive neutrals at the plasma-solid interface. We present a simulation study of feature topography evolution under Cl@sub 2@ and HBr plasma etching using a deterministic approach. In this work, we use the ballistic transport and reaction model that was presented by Cale and Raupp.@footnote 1@ Fluxes from the plasma directly to the feature surface, from diffuse re-emission of neutrals from the surface, and from both specular and non-specular reflection of ions are considered. To consider the angular and energy dependence of the etch rate, we use the work of Chang and co-workers.@footnote 2@ In order to capture the bimodal shape of ion energy distribution, we regard the bombarding ions as the sum of independent monoenergetic species. We consider the ion angular distribution of each monoenergetic species, so that the effect of ion energy distribution on the shape of feature profile can be investigated. We compare the shape of etched feature profiles, some of which exhibit microtrenching, to experimental data for Cl@sub 2@ and HBr plasma etching. Our simulations show that the difference in etched profiles can be regarded as due to the different characteristics of the specular reflection and the dependence of the etching yield on incident angle for Cl@sub 2@ and HBr plasma. Simulation results are compared with experimental data and Monte Carlo based simulation from the literature. @FootnoteText@ @footnote 1@ T.S. Cale and G. B. Raupp, A Unified line-of-sight model of deposition in rectangular trenches, J. Vac. Sci. Technol. B 8 (6), 1990 @footnote 2@ Jane P. Chang, Arpan P. Mahorowala, and Herbert H. Sawin, Plasma-surface kinetics and feature profile evolution in chlorine etching of polysilicon, J. Vac. Sci. Technol. A 16, 1998