On-chip integrated PS3 (Packaging-Stress Suppressed Suspension) for thermal-stress fress package of pressure sensors

A compact suspension-structure is on-chip integrated surrounding to a piezoresistive pressure sensing diaphragm for elimination of packaging-stress induced instability. The novel technology is named by us as PS³ (Packaging-Stress Suppressed Suspension). Using one single-side polished wafer and micromachining process only from the front-side, the cantilever-like PS³ structure is formed compactly around a piezoresistive pressure sensor to provide a packaging-process/substrate friendly method for low-cost but high-performance sensors. The tested results show that the sensor with PS³ structure has the same linear output sensitivity of 0.046mV/kPa as the sensor without PS³ structure has. But, the temperature-drift of the sensor with PS³ is only 0.016%/°C-FS that is about 15 times better than that of sensor without PS³. Obviously, the PS³ technique effectively eliminates the packaging-stress.