1. A method of making a plurality of bump structures on a substrate, comprising: immersing a substrate in a first plating bath, wherein the substrate is coupled to a cathode; and plating a first metal layer in openings of a plurality of bump structures, wherein the openings are lined with an under bump metallurgy (UBM) layer, the first metal layer is part of the plurality of bump structures, and a first anode in the first plating bath is patterned to deposit the first metal layer in the openings of the plurality of bump structures.