An under-bump metallization (UBM) structure for a substrate, such as an organic substrate, a ceramic substrate, a silicon or glass interposer, a high density interconnect, a printed circuit board, or the like, is provided. A buffer layer is formed over a contact pad on the substrate such that at least a portion of the contact pad is exposed. A conductor pad is formed within the opening and extends over at least a portion of the buffer layer. The conductor pad may have a uniform thickness and/or a non-planar surface. The substrate may be attached to another substrate and/or a die.