Abstract: The present invention provides a fingerprint sensing mechanism using a two-dimensional thermoelectric sensor array to capture the thermal image related to the ridges and valleys on the finger, wherein its fabricating method is totally compatible with integrated circuits processing. Using the body temperature of a human being as the stimulation source for biometrics, a temperature difference is produced from a ridge of a fingerprint contacting the thermoelectric sensor and the temperature gradient is converted into an electrical signal. A plurality of thermoelectric sensors arranged in a two-dimensional array forms a fingerprint sensor so as to obtain the electrical signal output of the ridge profile of the fingerprint.

Abstract: The present invention provides a fabrication method of a pressure type fingerprint sensor, which uses the commercial integrated circuit process to form the sensor and the processing circuit together on the same chip. The present invention comprises a plurality of capacitive pressure sensors arranged in a 2-D array and applies the charge sharing principle to each capacitive pressure sensor for signal reading. The main structure of each pressure sensor is a pair of plate electrodes with an air gap between them to form a plate sensor capacitor, wherein the plate electrodes comprise a floating electrode and a fixed electrode. When the finger ridge contacts the floating electrode, the pressure from the finger changes the spacing of the air gap so as to change the capacitance of the plate sensor capacitor. The 2-D sensor array can read the 2-D pressure distribution pressed by the finger ridge to construct the fingerprint pattern.