<title>Lithographic definition of channel and void structures in multilayer PZT microactuators</title>

Abstract

ABSTRACT We are investigating techniques to fabricate advanced microactuators cost efficiently and in particular to combine siliconmicrostructures with multilayer PZT microelements. Aiming at an increased freedom in design of multilayer PZT elements,various process steps to build channel and void structures in the actuator body are investigated. In a multilayer actuator,channels and voids can be used for transportation of fluids or to change transducer properties. A PZT green ceramic body isbuilt with internal sacrificial structures defmed using photolithography and patterned polymer foil and these structures areremoved during binder burnout. In difference to conventional green tape lamination the technique used in the presentedexperiments, wet building, tends to planarize consecutive layers cast. This is particularly advantageous for high aspect ratiosacrificial structures.Results show that possible channel dimensions range from 10 im up to above 200 jtm. The lower channel dimensionlimitation is determined by the surface roughness of a cast green layer and the grain growth during sintering. No sagging ofthe channels is observed at the investigated channel dimensions. The mechanical and chemical stability of the sacrificialmaterial during exposure to solvent and moderate heat is found to be important. The large scale manufacturing aspect of theinvestigated technique is also discussed.Keywords: Piezoceramic, Multilayer, Microactuator, Channel, Sacrificial structure