Experimentally validated computations of simultaneous ion and fast neutral energy and angular distributions in a capacitively coupled plasma reactor

Abstract

Accurate predictions of the ion energy and angular distribution functions (IEADFs) and fast neutral energy and angular distribution functions (FNEADFs), are essential for a range of critical applications in the plasma processing of thin film etching and deposition. Computationally efficient methods that can be applied to industrial reactor systems that are also validated across a range of operating conditions are essential for prediction of IEADFs and FNEADFs. In this work, we present a hybrid model where a capacitively coupled plasma (CCP) solution was computed using a fluid model and the IEADF/FNEADF was generated using a particle transport model with a multi-species Monte Carlo Collision model. We first compare the computed IEADFs across a range of pressures with experimental measurements for a CCP reactor. We predict FNEADFs that are typically difficult to measure experimentally but are believed to have a significant effect on etch/deposition process phenomena. Across a large pressure range, we observe significant fast neutral bombardment of the electrode surface with at least half the energy of the most energetic ions as well as an angular spread that is larger than that of the ions.