IEEE Transactions on Ultrasonics Ferroelectrics and Frequency Control · 2006 · 17 citations · 15 references
EngineeringMaterials EngineeringMaterials ScienceMicroelectromechanical SystemsMicrofabricationUltrasoundAcoustic MaterialsFabrication MaterialsMicrofabrication MaterialsMicrofabrication ProcessesTransducer TechnologyUltrasonicsAnnular Array TransducersFabricationMicroelectromechanical Systems TransducersMicroscale FabricationSol-gel ProcessingTransducer FabricationTransducersUltrasonic Transducers
A new micromolding technique for fabricating high-frequency (>20 MHz) ultrasound transducers has been developed. The technique combines sol gel processing with an epoxy-based, photo-resist Su-8 micromold to form miniature PZT structures. An advantage of this technique as compared to more traditional lithographic galvanforming and abforming (LIGA) processing is that the intermediate step of producing a nickel-plated mold is avoided. Instead, the PZT is formed directly using a photo-resist. The resulting structures can be fabricated with aspect ratios up to 3:1 and thicknesses up to 50 micro. We have successfully fabricated 50-micro-thick linear array elements with 23-micro-wide elements separated by 15 kerfs. A 50-micro thick, 2.5-mm diameter, five-element annular array structure with 20-micro kerfs also has been fabricated. The micromolded PZT composite has a density of 5.7-5.8 micro 0.4 g/cm3 and a thickness coupling coefficient as high as 0.32.
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Two-Dimensional Arrays for Medical Ultrasound
S.W. Smith, Gregg E. Trahey, Olaf T. von Ramm · Ultrasonic Imaging · 1992 · 150 citations