Embodiments of the present disclosure provide an apparatus comprising a substrate layer, a metal ring structure disposed on the substrate layer, the metal ring structure having an opening defined therein, and a solder mask layer coupled to (i) the metal ring structure and (ii) the substrate layer through the opening defined in the metal ring structure, the solder mask layer having a solder mask opening defined therein, wherein an edge of solder mask material defining the solder mask opening overlaps a portion of the opening defined in the metal ring structure. Other embodiments may be described and/or claimed.