Hybrid Plasma Modeling of Low-Pressure Oxygen Plasma in Capacitively Coupled Plasma Reactors

Dual-frequency low-pressure capacitively coupled plasmas (CCP) are widely used for reactive ion etching of dielectric thin films and chemical vapor deposition in the semiconductor industry. Computationally efficient fluid plasma simulations are generally used to understand plasma behavior in CCP reactors with respect to varying operating conditions which help us understand the effect of varying plasma operating conditions on the on-wafer process results. However, in low pressure conditions, the electrons mean free path can be long and kinetic effects are important. A full multi-dimensional multi-species particle plasma simulation is prohibitively expensive in terms of computational cost and time. In this paper, we discuss a hybrid plasma model where electrons are modeled as particles and ions and neutrals are modeled as fluid. We model oxygen only plasma that consists of multiple ionic species including those that are electronegative. The effect of gas temperature and assumed ion mobility and ion neutral collision cross-sections for the various ionic species on the new model results are analyzed and these results are compared with those of a fully particle simulation under the same operating conditions.