Kinetic simulations of low temperature plasmas used for plasma processing

Low-temperature kinetic plasma simulations using particle-in-cell (PIC) and Monte Carlo methods (DSMC/MCC) for the chemistry can provide many advantages over the more popular fluid simulations, including detailed information about the ion energy and angular distribution functions that are critical for plasma processing. In this presentation, two different types of simulations illustrating the power of kinetic modeling are demonstrated. The first is a macroscopic-scale simulation of an inductively coupled plasma (ICP). We demonstrate how implicit methods can make these challenging simulations feasible, and show that our numerical model captures salient physical effects (inductive coupling, sheath formation, plasma generation, etc.) of the ICP discharge. Efforts to hasten the convergence of these simulations to steady-state and to improve their predictive capabilities are also summarized. Secondly, we outline ongoing work to develop microscopic feature-scale simulations of a through-silicon-via etch process, obtaining potential boundary conditions and incident particle fluxes within the feature from larger-scale kinetic sheath computations. For both simulation types, ion energy-angle distributions at the wafer surface, electron kinetics, and the detailed physics of the sheath and presheath can be computed by our numerical model.