Effect of gas mixing ratio on etch behavior of ZrO(2) thin films in Cl(2)-based inductively coupled plasmas

Abstract

The analysis of the ZrO(2) thin film etch mechanism in the Cl(2)/Ar, Cl(2)/He, and Cl(2)/N(2) inductively coupled plasmas was carried out. It was found that an increase in additive gas fraction at fixed gas pressure and input power results in increasing ZrO(2) etch rate, which changes from 1.2 nm/min for pure Cl(2) plasma up to 3.15, 2.40, and 2.31 nm/min for 80% Ar, N(2), and He, respectively. Langmuir probe diagnostics and zero-dimensional plasma modeling indicated that both plasma parameters and active species kinetics are noticeably influenced by the initial composition of the gas mixture. From the model-based analysis of etch kinetics, it was shown that, similarly to the case of BCl(3)-based plasmas, the behavior of the ZrO(2) etch rate corresponds to the ion-flux-limited etch regime.