Flexible polysilicon strain gauge array

A flexible polysilicon strain gauge array has been realized using a surface micromachining technique with a SiO₂ sacrificial layer. The realized sensor array is mechanically flexible, which can be attached on non-planar surfaces. To realize the flexible strain gauge module, a new packaging scheme using a polyimide circuit board and an oxide based surface-micromachining was developed. The proposed packaging scheme completes the strain sensors and the circuit board on a single process, which eliminates additional assembly and alignment problems. The measured gauge factor shows that it is more sensitive than metal strain gauges. Unlike a single-crystal silicon strain gauge, the proposed polysilicon gauge has no limitations in the direction of strain.