3-D Microfabrication for In-Plane Optical MEMS Inertial Sensors

The demands of next generation missile systems call for both a smaller overall weights and form factor and better performance for assured position, navigation, and timing. Commercially available MEMS based IMUs offer attractive SWaP-C specifications but suffer from a lack of precision and accumulate too much error over time. Interferometer-based optical pickoffs are a promising solution to the noise limits of current sensors and may lead to high-performance MEMS accelerometers. EngeniusMicro, LLC has previously demonstrated promising fabrication technology to realize optical pickoff for MEMS accelerometers. In this proposal we propose to develop fabrication processes to meet critical dimension requirements and tolerances necessary and to realize a high-yield, high-throughput manufacturing process for optical pickoff accelerometers. We aim to address key challenges in making self-aligned optical components; precise placement and orientation of reflectors, and precise control over reflector geometry. Our new design features a fabrication process created to optimize the reflector and self-alignment structures with minimal manual alignment and handling. We will capture the dynamics and repeatability of the fabrication with a DOE study to understand process control requirements. After defining the systematic and stochastic effects driving fabrication, we will implement a design-based approach to create a released MEMS accelerometer with a self-aligned optical pickoff.