A laminate includes a plurality of buildup layers disposed on a core and a plurality of unit cells defined in the buildup layers. Each unit cell includes: at least one test via that passes through at least two of the buildup layers and that is electrically connected to testing locations on a probe accessible location of the laminate; and two or more dummy vias disposed in the unit cell. The dummy vias are arranged in the unit cell at one of a plurality of distances from the test via.