Evaluation of ESD hardness for fingerprint sensor LSIs

We evaluated the electrostatic discharge (ESD) hardness for some kinds of capacitive fingerprint sensor LSIs. In contact discharge tests, our sensor with the GND wall structure and another sensor with a GND demonstrated of ESD failure voltage above plusmn8 kV. On the other hand, in air discharge tests, ESD tolerance of our GND wall structure was over plusmn 20 kV, whereas that of the other GND structure was below plusmn 12 kV. It is evident from our findings that ESD immunity in the sensor LSIs obviously depends on the GND structure and our sensor LSI with the GND wall has the highest ESD tolerance.