Corrosive inorganic contamination on wafer surfaces after nickel-iron electroplating - Formation Mechanisms and Prevention

Electroplating of Nickel-Iron alloys is widely used in the production of ma gnetic heads for storage systems. Usually, the plating process is performed in acidic, salt-containing solutions. After the plating step, a complete r emoval of the plating salts is necessary to receive a clean surface. In dis advantageous cases, a precipitation of sticky particles is observed that ca nnot be removed from the plated surface without damaging the surface. Some of these substances (esp. nickel sulfates) might lead to severe local corro sion and thus might act as "time-bomb" in the later product. Non-corrosive precipitation, (i.e. nickel hydroxides) strongly hinder or even prevent the following production steps. In the present paper, the mechanisms of the origin of the different kinds o f precipitation arc described and the principle actions for their preventio n are given. An outlook is given for other possible technical applications.