Combined MEMS inertial sensors for IMU applications

Today MEMS inertial sensors have already entered a broad market area and have mastered the step into high volume mass production, as seen on 3-axis accelerometers. The competitive product innovation cycle however gives constant pressure on the development of multi-axis and multi-type sensor systems to finally conclude in a full inertial measurement unit (IMU). Up to now the combination of accelerometer and gyrometer on one chip was limited by the incompatibility of the different operational pressure requirements. In this paper we introduce a new technology approach enabling the allocation of different cavity pressures on wafer level. This new concept is being industrialized with the new combi sensor SD755, which contains in a first step one accelerometer and one angular rate sensor on the same silicon chip.