Micro IMU Utilizing Folded Cube Approach

One of the main challenges of developing a chip-level IMU is combining multiple high-performance sensors on a single die capable of detecting motion along independent directions with minimal cross-axis sensitivity. To address this challenge, a folded-chip approach is being explored utilizing a 3D SOI backbone suitable for high-aspect ratio sensor fabrication. Assembly is done on the wafer level and the panels are silicon-to-silicon welded, forming a compact rigid 6-axis system of sensors. Accelerometers and gyroscopes are fabricated in parallel with the folded structure on the same substrate, and are electrically and mechanically interfaced through flexible integrated thin-film polyimide hinges and interlocking silicon latches. Due to the advantages of high aspect ratio SOI based sensor fabrication, high-performance single axis sensors with low cross-axis sensitivity can be employed. The investigated folded-chip approach can be used to create an entire IMU including with integrated inertial sensors, clock, IC, and power source.