An integrated MEMS tactile tri-axial micro-force probe sensor for Minimally Invasive Surgery

In this paper, we describes an integrated MEMS tactile tri-axial micro-force probe sensor based on piezoresistive for Minimally Invasive Surgery (MIS) as it´s micro-structure, three-dimensional measurement and high resolution up to be micronewton (μN) scale. The sensor is 4 × 4 × 20.9 mm³. The sensing element of the sensor is fabricated on Silicon on Insulator (SOI) wafer by surface and bulk micromachining technology. It uses four cantilever beams supporting the suspended mass. Twelve relief pieoresisters formed by iron implant and Inductive Couple Plasmas (ICP) etching technology are placed on the beams to detect the applied force. The pyrex glass bonded on the bottom of the SOI wafer by anodic bonding technology is the overload protection element. The tactile element is the quartz fiber probe which is no-pollution, low cost, small size and easy to process. It is glued on suspended mass of the sensing element by epoxy resin. After fabrication, the sensor is packaged and tested by precision test bench and analytical balance. The experimental results illustrate that the sensor has excellent characteristics especially with resolution better than 3μN.