Features of the Kinetics of Bulk and Heterogeneous Processes in CHF3 + Ar and C4F8 + Ar Plasma Mixtures

Abstract

We carry out a comparative study of the kinetics of plasma-chemical processes and plasma composition in CHF₃ + Ar and C₄F₈ + Ar mixtures under the conditions of a high-frequency (13.56 MHz) induction discharge. Using diagnostic methods and plasma modeling, the general features and differences of the plasma’s electrophysical parameters in the studied systems are established together with the key bulk processes that determine the stationary concentrations of neutral particles. Тhe CHF₃ + Ar system in the range 0–75% Ar is shown to be characterized by lower values of the flux densities of the fluorine atoms and polymer of the forming radicals. Model analysis of the kinetics of the heterogeneous processes (etching, polymerization, degradation of the polymer film) confirmed the advantage of the C₄F₈ + Ar system of silicon etching anisotropy and etching selectivity compared to the SiO₂/Si system.