Patterned and planarized under-bump metallization

A method of fabricating an electronic device substrate, comprising:

• forming a repassivation material layer having a substantially planar surface on a substrate from a first electrically nonconductive material above a substrate having an electrical contact pad;
• forming an aperture in the repassivation material layer that exposes an electrical contact pad on the substrate;
• and
• forming, within the aperture, a metalized pad that is surrounded by and coplanar with the repassivation material layer along an edge of the aperture, wherein the metalized pad has a solderable surface and electrically contacts the electrical contact pad;
• wherein forming the metalized pad includes forming metalized fingers that extend radially from an outer boundary of the metalized pad in an interdigitated arrangement with the repassivation material layer.