Patent ID: 8772950

Claim:
An apparatus, comprising: a substrate core with a die attach region for attaching an integrated circuit die to the substrate core on a die side surface, and regions outside of the die attach region including corners of the substrate core, the die attach region including all portions of the substrate core laterally covered by the integrated circuit die in a plan view and including conductive lands for attaching conductive terminals of the integrated circuit die; at least one dielectric layer overlying the substrate core; and at least one guard ring formed adjacent a corner of the substrate core and in the region outside of the die attach region in a plan view, the at least one guard ring comprising: a first trace overlying the dielectric layer having rectangular portions extending in two directions from the corner of the substrate core and in parallel to external edges of the substrate core; a second trace underlying the dielectric layer and formed in correspondence to the first trace; and at least one via extending through the dielectric layer and coupling the first trace and the second trace; wherein the first trace, the at least one via, and the second trace form a one via stack.