Advanced surface micromachining process for inertial sensors

Abstract

An advanced micromachining process has been developed to further enhance the performance and to reduce the size of mass-produced inertial MEMS. In this new platform technology two independent silicon layers instead of one can be used to form more complex 3D-like masses, springs, and free-standing electrodes. The first accelerometer generations for automotive and CE applications are already in series production and demonstrate the capabilities of the new technology, for example by exhibiting an unparalleled offset stability. The new technology can also be used to build advanced multi-axis gyroscopes with improved performance. As an example, first prototypes of gyroscopes show an increase of roll and pitch sensitivity of approximately 40% compared to standard designs with the same sensor core size. Moreover, the seismic mass of the gyroscopes can be more flexibly adjusted to improve, e.g., the capability of electrostatic quadrature cancellation.