Mechanisms of Pb(Zr0.53Ti0.47)O-3 thin film etching with ECR/RF reactor

Ferroelectric capacitive devices for memory and MEMS applications require p atterned ferroelectric thin films with high anisotropic etched features. In this paper, physical and chemical parameters during etching of Pb(Zr0.53Ti 0.47)O-3 (PZT) by a dual frequency ECR/RF reactor have been investigated. T he removal characteristics of blanket films and films with a patterned mask were investigated as a function of gas chemistry (Ar, halogen gases), subs trate bias RF power and working pressure (from 5 x 10(-4) Pa to 1Pa). The e tch processes were characterized in terms of etch rate, selectivity and mas k stability. High etching rate processes (up to 70 nm/min with removable ph otoresist mask) were obtained and micron scale patterns were demonstrated. The impact of the etch process on the RZT surface layer modification was ch aracterized by AFM, SEM, TEM and XPS. A strong influence of process chemist ry and RF bias power on etching selectivity and surface topography (roughne ss, involatile residues) was observed. No surface damage layer was detected by Transmission Electron Microscopy. However XPS revealed fluorine (up to 34%) and chlorine radicals (below 10%) in a 10nm thick surface layer.