A Level Set Approach to a Unified Model for Etching, Deposition,
and Lithography, I: Two-dimensional Simulations
D. Adalsteinsson and J.A. Sethian
Journal Computational Physics, Vol. 120, No. 1, pp. 128-144, 1995.
We apply a level set formulation to the problem of surface advancement
in a two-dimensional topography simulation of deposition, etching,
and lithography processes in integrated circuit fabrication.
The level set formulation is based on solving
a Hamilton-Jacobi type equation for a propagating level set function,
using techniques borrowed from hyperbolic conservation laws. Topological
changes, corner and cusp development, and accurate determination of
geometric properties such as curvature and normal direction are
naturally obtained in this setting. The equations of motion of a unified
model, including the effects of isotropic and unidirectional deposition
and etching, visibility, surface diffusion, reflection, and material
dependent etch/deposition rates are presented and adapted to a level set
formulation. The development of this model and algorithm naturally extends
to three dimensions in a straightforward manner, and is
Part II of this paper.
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