Development of a Single-Mass Five-Axis MEMS Motion Sensor

MEMS (Micro-Electro-Mechanical Systems) are being included in an increasing number of applications in automotive systems, particularly because of their small size and cost. However, most automotive applications require more information than can be provided by a single MEMS motion sensor. We report on the development of a MEMS motion sensor that can detect acceleration along three axes and angular velocity around two or three axes using a single proof mass, enabling the integration of multiple applications into a single device. The sensor consists of four support springs patterned into the device layer of an SOI (Silicon on Insulator) wafer and a single proof mass formed by etching through the handle layer using DRIE (Deep Reactive Ion Etching). We present the fabrication and packaging process and modeling results for the sensor.