Some environmentally conscious processes in electronic applications

This paper describes two different processes applied to the electro and electroless deposition-of metals, with a view to introduce conditions which are environmentally sound. The first part deals with the use of an environmentally safe, ph-free conductive polymer material which has electronic conductivity close to metals and which can therefore be applied for electrochemical deposition purposes. In this paper we show the use of this material as a temporary cathode in an electrochemical cell to achieve the plating of metal conductors into microhole structures practiced in thin film non conductive substrates. The second part of the paper deals with the description of a cyanide-free electroless gold system. We will update the status of the chemical composition of the bath, its stability in different media as well as the deposition rate under various conditions. Also, description of the process parameters to achieve higher deposition rates for film thickness up to several microns will be given. The composition of this bath offers a dual advantage from the standpoint of the elimination of toxic cyanide as well as the low pH operation which makes the system compatible with polyimides and high pH sensitive resists.