Three-Dimensional Plasma Etching Simulation using Advanced Ray Tracing and Level Set Techniques

We present three-dimensional simulation techniques for plasma etching processes. Models based on Langmuir-type adsorption and on ballistic particle transport at feature scale can be efficiently solved in three dimensions. Surface coverages are self-consistently calculated. The local sputter rates of ions and the fluxes of neutrals are computed using modern ray tracing algorithms. In this way angle and energy dependent sputter yields or specular reflections of ions can be incorporated in a natural manner. For the time evolution of the surface we apply a recently developed fast multilevel-set framework. Our simulation techniques are demonstrated using a SF6/O2 plasma etching process model.