A new sensor structure and fabrication process for a single-chip fingerprint sensor/identifier LSI

We propose a new sensor structure and the fabrication process for a single-chip fingerprint sensor/identifier LSI in which the sensor is stacked on a 0.5 /spl mu/m CMOS LSI. We investigate the influence of electrostatic discharge (ESD), mechanical stress, and water penetration on the sensor's reliability. The results reveal ESD tolerance is obtained at the value of 2.0 kV, the sensor is immune to mechanical stress under the condition of 1 MPa tapping tests, and it is protected against contamination by a passivation film. The tests confirm that the sensor has sufficient reliability for conventional identification usage.