Etching Characteristics and Mechanisms of Pb(Zr,Ti)O3, Pt, and SiO2 in an Inductively Coupled HBr/Cl2 Plasma

Abstract

An investigation of the etching characteristics of Pb(Zr,Ti)O3 (PZT), Pt, and SiO2 in an inductively coupled HBr/Cl2 plasma as functions of gas mixing ratio at constant total gas pressure (6 mTorr), gas flow rate (40 sccm), input power (700 W), and bias power (300 W) was carried out. It was found that the PZT etching rate exhibits a maximum of 23.8 nm/min at 60% Cl2, while the highest PZT/SiO2 and PZT/Pt etching selectivities correspond to 20 and 40–60% Cl2, respectively. Plasma diagnostics by a double Langmuir probe and a global (zero-dimensional) plasma model provided the data on plasma parameters, densities and fluxes of plasma active species. It was considered that the PZT etching process appears in the neutral-flux-limited or transitional regime of an ion-assisted chemical reaction, and the nonmonotonic behavior of the PZT etch rate may result from the change in reaction probability.