EVALUATION OF THE FABRICATION OF PRESSURE SENSORS USING BULK MICROMACHINING BEFORE IC PROCESSING

Polysilicon piezoresistive pressure sensors were fabricated in a standard IC fab, using micromachined, direct bonded silicon wafers. A standard IC process was used, and no compatibility problems were observed. Pressure sensors with excellent characteristics were obtained. Temperature coefficients of resistivity and offset (TCR and TCO) of respectively 0.084 +/- 0.004% K-1 and 0.006+/-0.001% K-1 were measured. The technology used gives the possibility to optimize sensitivity, overpressure protection and pressure range, even at the same time.