An optical sensor structure is provided. The optical sensor structure includes a sensor pixel array in a substrate, a light collimating layer on the substrate, and at least one through-substrate via. The sensor pixel array has a plurality of sensor pixels. The at least one through-substrate via extends from a first surface to an opposite second surface of the substrate. The at least one through-substrate via is in the sensor pixel array and vertically misaligned with the plurality of sensor pixels.