Development of CMOS Process Compatible Force Sensor and its Application to Probe Card

This thesis aims to apply a standard CMOS process to develop a Wheatstone-bridge- based piezoresistive force sensor. This CMOS-compatible piezoresistive force sensor with small area and easy fabrication consists of a thin-film receiver made by passivation, silicon oxide and a piezoresistive layer made by the polycrystalline silicon respectively. Additionally, utilize the RLS etching process offered by CIC to conduct its post-process. Combining MEMS with the electroforming process enables us to fabricate vertical spring probes featuring strength feedback function, making it possible to monitor wafer-level probe card either on-line or off-line. In traditional, the working probe naturally sustaining repeated bending actions and wear, absolutely needs a mechanism to prevent it from being damaged, caused by the change of the probe´s geometry and the increase of the contact resistance. Therefore, in this study, we develop a CMOS-based chip in connection with the electroformed probes to detect each of their counterforce, contact resistance to evaluate if their contact force and coplanarity are controlled within safe range. This breakthrough technology of installing a piezoresistive force sensor to fully monitor the working probe cards helps to save time and manpower for broken probes repair.