Concerning the Effect of Type of Fluorocarbon Gas on the Output Characteristics of the Reactive-Ion Etching Process

Abstract

The comparative research of the parameters, steady-state composition, and the effects of heterogeneous interaction in the plasma of fluorocarbon gases CxHyFz with various z/x relations in conditions of an induction RF (13.56 MHz) discharge is carried out. The binary systems CxHyFz + Ar based on CF4 (z/x = 4), CHF3 (z/x = 3), and C4F8 (z/x = 2) are used as the subjects of research. Through the methods of diagnostics and simulation of plasma we found (a) the reasons of the differences in the physical parameters (temperature and density of electrons, energy of ion bombardment) of the plasma in the studied systems; (b) the special characteristics of the kinetics of the plasma-chemical processes determining the steady state concentrations of fluorine atoms and polymer-forming radicals; and (c) the special characteristics of the kinetics of the heterogeneous process forming the output parameters (rate, selectivity, anisotropy) of the reactive ion etching of Si and SiO2.