A MICROMACHINED POLY(VINYLIDENE FLUORIDE-TRIFLUOROETHYLENE) TRANSDUCER FOR PULSE-ECHO ULTRASOUND APPLICATIONS

A process for manufacturing epoxy-backed integrated poly(vinylidene fl uoride-trifluoroethylene) [P(VDF-TrFE)] transducers using standard mic rofabrication techniques is reported. The P(VDF-TrFE) is spin-cast ove r a silicon membrane, which is backfilled with epoxy to yield a wide-b and, half-wavelength (lambda/2)-resonant device suitable for pulse-ech o use. The main advantages of the fabrication process are the ability to build several devices at a time on a single wafer and the potential for integrating electronics on the same substrate with the transducer . Twelve 31-MHz 2-mm diameter transducers were fabricated on a 2-in di ameter silicon wafer, A pulse length of about 100 ns was achieved with a sample device, which exhibited a dynamic range of 40 dB and an inse rtion loss of 48 dB, The axial resolution of the transducer in healthy vascular tissue was estimated to be 79 mu m.