Computational Optimization of Plasma Chemistry by Reducing Chemical Species and Reactions in Plasma Models

Simulations of plasma processing chambers are used to quantify the effect of source design and process parameters on the species densities, fluxes and energies. A plasma chemistry mechanism involving a large number of species and reactions results in prohibitively high computational cost. In this study, we develop a systematic methodology for eliminating unimportant species and less impactful reactions from computations in plasma simulations. Our plasma model employs Poisson equation for electric field, continuity equations for species densities and energy equation for electrons. The fluxes and energies of the species to the surface derived from the plasma model determine surface processes. We quantify the impact of each reaction and species on the overall species densities at the end of a simulation using a well-defined cost function. Among the species and reactions, we eliminate those that have negligible qualitative impact on the surface chemistry. We then map the plasma source design and process parameter range for which such elimination is possible. This optimized plasma chemistry enables plasma simulations with complex chemistry to be more practical for deposition and etching processes.