Certain embodiments herein relate to methods and apparatus for processing a partially fabricated semiconductor substrate in a remote plasma environment. The methods may be performed in the context of wafer level packaging (WLP) processes. The methods may include exposing the substrate to a reducing plasma to remove photoresist scum and/or oxidation from an underlying seed layer. In some cases, photoresist scum is removed through a series of plasma treatments involving exposure to an oxygen-containing plasma followed by exposure to a reducing plasma. In some embodiments, an oxygen-containing plasma is further used to strip photoresist from a substrate surface after electroplating. This plasma strip may be followed by a plasma treatment involving exposure to a reducing plasma. The plasma treatments herein may involve exposure to a remote plasma within a plasma treatment module of a multi-tool electroplating apparatus.