A method and apparatus for testing the electrical characteristics, such as electrical continuity, is provided. A substrate, such as a wafer or an interposer, having a plurality of through vias (TVs) is provided. Along one side of the substrate, a conductive layer electrically couples two or more of the TVs. Thereafter, the electrical characteristics of the TVs may be test by, for example, a probe card in electrical contact with the TVs on the other side of the substrate. During testing, current passes through a first TV from a first side of the substrate, to the conductive layer on a second side of the substrate, to a second TV, and back to the first side of the substrate through the second TV.