Design, Manufacturing and Test of a High-Precision MEMS Inclination Sensor for Navigation Systems in Robot-Assisted Surgery

Abstract

Robot supported minimally invasive interventions are state of the art in operating theatres. To increase the accuracy of surgical instrument positioning, high-precision motion tracking systems are required. The miniaturization of microelectromechanical systems (MEMS) facilitates the placing of orientation detection sensors close to the mounting of the surgical instrument to enhance positioning accuracy. A high resolution inclination sensor was developed using the innovative approach of laser-micro-welding. Trench sizes down to 800 nm are fabricated with more than 6-fold increase in aspect ratios (structure depth to electrode gap) compared to sensors without gap reduction. Electrical and physical tests as well as finite-element-simulations were performed. An increased sensitivity from 7.2 fF/° up to 60 fF/° was verified for the sensor with reduced electrode gap and a customized ASIC.