Method to plate C4 to copper stud

Abstract

A method for plating a second metal directly to a first metal without utilizing a mask. A semiconductor substrate is provided including at least one metal feature and at least one insulating layer covering the metal feature and the substrate. At least one recess is formed in the at least one insulating layer thereby exposing at least a portion of the metal feature. At least one conductive barrier layer is formed over the insulating layer and the exposed portion of the metal feature. A plating seed layer of a first metal is formed over the at least one barrier layer. A photoresist layer is deposited over the plating seed layer. Portions of the photoresist layer and of the plating seed layer outside of the at least one recess are removed. Photoresist remaining in the at least one recess is removed. A second metal is electroplated to the plating seed layer in the recess.

Dependencies are inferred from the claim text.