Heterogeneous integration towards an ultra-compact and thin optical displacement microsensor

This paper focuses on heterogeneous integration technology and its application in optical displacement microsensor. The integration is based on the Au-Au surface-activated bonding at a relatively low bonding temperature of 150degC. Applying this technique, an ultra-compact and thin optical displacement microsensor with three-dimensional structure (2.8 mm times 2.8 mm times 1 mm thick) was fabricated. The feasibility of displacement measurement based on grating interferometer was demonstrated using the prototype microsensor.