A process including forming an a backside-illuminated (BSI) image sensor in a substrate, the image sensor including a pixel array formed in or near a front surface of the substrate and one or more circuit blocks formed in the substrate near the pixel array, each circuit block including at least one support circuit. An interconnect layer is formed on the front surface of the substrate that includes a dielectric within which are embedded traces and vias, wherein the traces and vias electrically couple the pixel array to at least one of the one or more support circuits. An isolation trench is formed surrounding at least one of the one or more circuit blocks to isolate the pixel array and other circuit blocks from noise generated by the at least one support circuit within the circuit block surrounded by the isolation trench. Other embodiments are disclosed and claimed.