a substrate having a core with vias disposed therein . a reference layer is formed on the core , with voids in the reference layer that are formed around the vias in the core . traces on a routing layer overlie the reference layer . also included is a contact layer with contacts disposed in a contact pattern . the core is logically divided into sections , and the vias within a given one of the sections are aligned in rows substantially along a first direction . at least a portion of the vias are not aligned with the contact pattern . the voids in the reference layer within the given one of the sections are also aligned in rows substantially along the first direction and aligned with the vias . further , the traces within the given one of each of the sections are also aligned substantially along the first direction between the rows of voids , and not substantially overlying the rows of voids .