Etching characteristics of Pb(Zr,Ti)O-3, Pt, SiO2 and Si3N4 in an inductively coupled HBr/Ar plasma

Abstract

An investigation of the etching characteristics of Pb(Zr, Ti)O-3 (PZT), Pt, SiO2 and Si3N4 in an inductively coupled HBr/Ar plasma as functions of gas mixing ratio at a constant gas pressure (4mTorr), total 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 at 60-70% Ar, while the highest PZT/Si3N4, PZT/SiO2 and PZT/Platinum (Pt) etch selectivities correspond to 40%, 60% and 100% Ar, respectively. Plasma diagnostics by a double Langmuir probe and a global (zero-dimensional) plasma model provided data on plasma parameters, densities and fluxes of plasma active species. It was proposed that, in HBr-rich plasmas, the PZT etching process appears in the transitional etch regime of the ion-assisted chemical reaction and the non-monotonic behavior of the PZT etching rate results from the concurrence of both chemical and physical etch pathways.