AVS 50th International Symposium
    Plasma Science and Technology Thursday Sessions
       Session PS2-ThM

Paper PS2-ThM6
Three-dimensional Feature Profile Evolution during Etching of Porous Dielectric Materials

Thursday, November 6, 2003, 10:00 am, Room 315

Session: Low k Dielectric Etch
Presenter: Y.H. Im, Rensselaer Polytechnic Institute
Authors: Y.H. Im, Rensselaer Polytechnic Institute
M.O. Bloomfield, Rensselaer Polytechnic Institute
T.S. Cale, Rensselaer Polytechnic Institute
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Porous materials are being widely investigated for use as low dielectric constant materials for state-of-the-art integrated circuit (IC) interconnects. The patterning of these materials is one of the current challenges to be overcome for application to next generation ICs. Although conventional etching technologies can be used for this purpose, one of the barriers in adapting them to these materials is the lack of the fundamental understanding of how the complicated etching mechanisms interact with the inherently 3D structure of porous materials. It is desirable to employ 3D computer simulations to answer questions that cannot be addressed by 2D simulators. We present a fully 3D simulation study of feature topography evolution under various etching processes. As a part of this effort, we have used the parallel levelset environment for nanoscale topography evolution (PLENTE) to track the evolution of systems in 3D. PLENTE is used with the ballistic transport and reaction based process simulator EVOLVE, which in turn uses a 3D Monte Carlo view factor code, to predict the fluxes and coverages of chemical species on the evolving substrate. We compare the shape of etched feature profiles to experimental data for porous dielectric materials. Etch rate and feature profile evolution were examined as functions of process conditions and porous material properties such as porosity and average pore size. This simulation technique is designed to help process engineers understand new phenomena observed in etching of porous dielectric materials and smooth the adaptation of conventional etching recipes to porous substrates.