A package includes a conductive pad, with a plurality of openings penetrating through the conductive pad. A dielectric layer encircles the conductive pad. The dielectric layer has portions filling the plurality of openings. An Under-Bump Metallurgy (UBM) includes a via portion extending into the dielectric layer to contact the conductive pad. A solder region is overlying and contacting the UBM. An integrated passive device is bonded to the UBM through the solder region.