A Si MEMS microbearing with integrated safety sensors for surgical applications

A silicon micromachined bearing was designed and fabricated consisting of a pair of self-aligning v-grooves. The two Si v-grooves were bonded together to form the three-dimensional structure through solder bumps of 75 mum dia meter that provide alignment with a crucial vertical displacement tolerance . The microbearing includes integrated diode temperature sensors that serve to monitor a safe operating range under load. Current versus temperature c urves and finite element analysis simulate the range of diode sensitivity. This three-dimensional structure, fabricated by silicon technology, demonst rates that a four to ten fold reduction in surgical cutting tool size can b e achieved by utilizing the micromachined silicon microbearing in a micro-e lectromechanical system (MEMS) device. A prototype microtool has been bench tested and compared with realistic operating conditions. Based on this com parison, the microbearing holds promise for application in microsurgical cu tting tools or as a MEMS cutting tool for surgical applications. (C) 2000 E lsevier Science Ltd. All rights reserved.