Pulse and pulse reverse plating of copper from acid sulphate solutions

Abstract

This paper describes how copper plating is influenced by modulated current. By unipolar pulse plating smooth, compact and fine grained structures can be obtained, but the macro throwing power is worse than by direct current plating. The best throwing power is obtained by pulse reverse plating. In additive containing solutions, excellent throwing power has been obtained at the following parameters: T c/T a=20, i a/i c=1–3·5 and Q a/Q c<0·2. Without additives the surface becomes less smooth. Finally, superimposed pulse reverse plating has the possibility to combine the advantages of uni- and bipolar pulse plating in an additive free process.