3D direkt laser fabrication of ultrasound transducers

Ultrasound transducers are widely used in non-destructive testing, medical applications, and biology. Usually, ultrasound transducers are either capacitive micromachined ultrasonic transducers or commonly used piezoceramic-based systems. Capacitive micromachined ultrasonic transducers are traditionally fabricated in multi-step subtractive processes, e.g., wafer-bonding. In this presentation, we show that additive fabrication of capacitive micromachined ultrasonic transducers with different designs using 3D direct laser writing via multi-photon absorption is feasible. 3D direct laser writing is a 3D micro-printing technology that enables design freedoms that surpass the capabilities of traditional processes. Here, we present the fabrication of transducers with a center frequency between 500 kHz and 3.5 MHz – a frequency range often employed in air ultrasound in non-destructive testing. We benchmark thus fabricated ultrasound transducers based on oscillation amplitude, center frequency, bandwidth and transient response in air as well as under water. The results show that thus fabricated transducers are competitive with traditionally fabricated transducers.