Polymer-Based Resonator for Ultrasonic Imagine Applications

Capacitive micromachined resonator for ultrasonic imaging technology is a prime candidate for next generation ultrasonic imaging transducers. Medical and healthcare imaging and the physiotherapy societies have expressed growing interest in capacitive micromachined resonator over the years. This paper focuses on polymer based fabrication technologies for capacitive ultrasonic resonator using in imaging applications. In this paper, the design, simulation, and fabrication results of a polymer based resonator for airborne ultrasonic application are presented. Due to its outperformance in terms of processing temperature and cost, this paper will also introduces the new concept in detail about sacrificial layer release processes during the fabrication of a polymer vibratile membrane. Process variations are compared qualitatively and quantitatively whenever possible. Through these study, it was concluded that polymer resonator technology was superior in terms of process control, yield, and uniformity. Because the number of steps and consequent process time were reduced, turn-around time was improved significantly. Furthermore, a resonator array was then designed and fabricated with a target DC actuation voltage of less than 20V with a resonance frequency at 1.7 MHz. The experimental results showed the potential of this resonator for healthcare imaging and the airborne applications in physiotherapy.