Under screen sensor assembly

A sensor assembly that includes a silicon substrate and a sensor integrally formed on or in its top surface. Bond pads are formed at the substrate top surface and electrically coupled to the sensor. A trench is formed into the top surface, extending toward but not reaching the substrate's bottom surface. Conductive first traces each extend from one of the bond pads and down into the trench. One or more holes are formed into the bottom surface of the substrate and extend toward but do not reach the top surface. The one or more holes terminate at the bottom of the trench in a manner exposing the conductive first traces. Conductive second traces each extend from one of the conductive first traces at the bottom of the trench, along a sidewall of the one or more holes, and along the bottom surface of the silicon substrate.