A substrate for use in fabrication of an integrated circuit has a layer with a plurality of conductive interconnects. The substrate includes a semiconductor body, a dielectric layer disposed over the semiconductor body, a plurality of conductive lines of a conductive material disposed in first trenches in the dielectric layer to provide the conductive interconnects, and a closed conductive loop structure of the conductive material disposed in second trenches in the dielectric layer. The closed conductive loop is not electrically connected to any of the conductive lines.