Three-axis MEMS inertial sensor for automobile applications

A three-axis microelectromechanical systems (MEMS) inertial sensor measuring two-axis acceleration and angular rate (rotation) has been developed for an electronic stability control (ESC) system for automobiles. We combined the angular rate detection part with the two-axis acceleration detection parts on a single MEMS chip to miniaturize the sensor. The two detection parts were designed to work under different environmental pressures through a two-step wafer level package (WLP) process to achieve the required sensitivity for the gyroscope with excellent vibration immunity for the accelerometers. We report on the design concept and test results of the three-axis MEMS inertial combined sensor and the manufacturing processes of the two-step WLP and through-silicon vias (TSVs).