| abstract |
An embodiment includes an ultrasonic sensor system comprising: a backend material stack including a first metal layer between a substrate and a second metal layer with each of the first and second metal layers including a dielectric material; a ultrasonic sensor including a chamber, having a negative air pressure, that is sealed by first and second electrodes coupled to each other with first and second sidewalls; an interconnect, not included in the sensor, in the second metal layer; wherein (a) a first vertical axis intersects the substrate, the chamber, and the first and second electrodes, (b) a second vertical axis intersects the interconnect and the substrate, (c) a first horizontal axis intersects the chamber, the interconnect, and the first and second sidewalls, and (d) the first and second electrodes and the first and second sidewalls each include copper and each are included in the second metal layer. |