Monte Carlo simulation of fast neutrals produced and transported in a dual-frequency capacitively coupled Ar/CF ₄ plasma sheath

Abstract We developed a single/dual-frequency (DF) sheath model for arbitrary gas mixture plasmas by modifying the previous model for noble gas plasmas and by adopting ion collision cross-sections generated using DNT+DM in order to simulate fluxes and energy-angular distribution functions (EADFs) of fast neutrals produced in the sheath and transported to the wafer surface. In the 46th International Symposium on Dry Process (DPS2025), an application of the new sheath model to an Ar/H 2 capacitively coupled plasma (CCP) was demonstrated after proving its validity by comparing with data measured in Ar rf and DF CCPs. In this paper, we apply the same model to a DF CCP in a mixture of Ar and CF 4 gases and present the EADFs of various fast neutrals produced due to ion-neutral reactions in the sheath. Through the simulation, it is found that the EADFs of fast fragment neutrals are apparently characterized by two distributions which originate from ion dissociation and gas molecule dissociation. Furthermore, ion dissociation mechanisms in the sheath are investigated and discussed in detail.