Dry Etching of PZT Thin Films for Bilayer Actuator Realization

Abstract

Reactive Ion Beam Etching (RIBE) of Pb(Zr,Ti)O3 thin film is performed for the via formation on a bilayer actuator. This actuator has been developed in the frame of health monitoring system for aircraft composite structures. The bilayer realization requires bore vias to connect the different conductive layers. It represents a 4 μ m thick PZT layer to etch. The etching conditions have been optimized to obtain high PZT etch rate and high selectivity ratio. The use of Ar/CHF3 gas mixture allows to reach a PZT etch rate of 950 Å/min, and a PZT/photoresist selectivity of the order of 7. Such a result makes possible the etching of high PZT thickness (several μ m). We have demonstrated that RIBE was an appropriate technique to perform PZT vias.