An examples includes a substrate, including a conductive trace and a layer disposed on top of the conductive trace, the layer defining at least one cavity extending to the conductive trace and an electrical probe disposed in the cavity, with solder coupling the electrical probe to the conductive trace. The electrical probe can include a high yield strength wire core including a refractory metal and a thin oxidation protection layer concentrically disposed around high yield strength wire core and providing an outside surface of the electrical probe, the thin oxidation protection layer including predominantly one or more materials selected from gold, platinum, ruthenium, rhodium, palladium, osmium, iridium, chromium, and combinations thereof, wherein the solder fills the cavity and is coupled to the electrical probe inside the cavity, disposed between the electrical probe and the layer.