Wafer level fabrication of high performance MEMS using bonded and thinned bulk piezoelectric substrates

Abstract

We report a batch-mode fabrication technology for integration of bulk piezoelectric materials into MEMS devices, and test results of high-performance out-of-plane piezoelectric actuators fabricated with this technology. Low-temperature (200°C), reliable AuIn and Parylene bonding of PZT wafers/dies on Si wafers is achieved, and lapping is used to obtain ≪10µm PZT films. Conservation of the piezoelectric properties is confirmed with a hysteresis measurement. Additionally, square and circular shaped PZT diaphragms with 4mm×4mm, 2mm×2mm, and 1mm×1mm sizes operating in the d31-mode are fabricated with a 2-mask fabrication process. Greater than 12µm peak-to-peak deflection is obtained by actuation of a 1mm2 diaphragm at resonance (110.9kHz) with a power consumption of ≪7mW.