Characterisation of an epoxy filler for piezocomposite material compatible with microfabrication processes

High frequency ultrasound transducer arrays that can operate at frequencies above 30 MHz are needed for high resolution medical imaging. A key issue in the development of these miniature imaging arrays is the need for photolithographic patterning of array electrodes. To achieve this directly on a 1-3 piezocomposite requires not only planar, parallel and smooth surfaces, but also an epoxy composite filler that is resistant to chemicals, heat and vacuum. This paper reports the full characterisation of an epoxy filler suitable for fine-scale piezocomposite fabrication as well as photolithographic processes.