Acoustic and electromechanical properties of 1–3 PZT composites for ultrasonic transducer arrays fabricated by sacrificial micro PMMA mold

Manufacturing method for 1–3 PZT composites for medical ultrasonic transducer array (UTA) using sacrificial polymethyl-methacrylate (PMMA) micro molds was investigated. The purpose of study was to compare this proposed method (briefly, micro-pressing) with conventional dicing method for UTA fabrication. The cell size was 135μm × 135μm with the 35μm gap between cells, and the cell height was 170μm. Microstructure of 1–3 PZT composites was dense and had uniform morphology. Dielectric constants at 1kHz were 2627 for the dicing method and 2221 for the micro-pressing method. Two methods produced similar values for the thickness mode electromechanical coupling coefficients (Kt): 73% for the dicing method and 68% for the micro-pressing method. Acoustic properties of fabricated ultrasonic transducer by the dicing method were similar to those of the micro-pressing method. Microstructure, electromechanical properties and acoustic properties of 1–3 PZT composites fabricated by the micro-pressing method were comparable to the properties obtained with the conventional dicing method. The micro-pressing method is a cost-effective way of manufacturing micro-ceramic rod arrays with high aspect ratio based on the batch type LIGA process.