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Summary to the lecture of Mr. Thomas Ebert during the annual meeting of the German electroplating society 2007 in Garmisch-Partenkirchen

High Performance Contacts for Printed Circuit Board and Semiconductor Production
In most cases, metals are electrolytically deposited from aqueous electrolytes. The coating of metal surfaces in a cyanide molten salt bath containing platinum in an inert gas atmosphere is far less known. With high temperature electrolysis or abbreviated HTE, platinum is deposited at high temperatures (approx. 550°C) under exclusion of oxygen. In this way even refractory metals such as titanium or niobium, which have a high affinity for oxygen and therefore tend to be passive, can be plated with high adhesive strength. From the water-free process, ductile, very pure and extremely corrosion-resistant platinum layers up to layer thicknesses > 50 µm can be deposited crack-free without embrittlement since no hydrogen being formed will be incorporated into the layer. During acid copper plating of printed circuit board and semiconductor structures, the demands on the contacts used for transferring mostly pulsed currents are extremely high. Safe current transfer must be guaranteed over a long period of time despite the superimposed stressing by mechanical and electrochemical loads. As regards mechanical loading, the outstanding ductility and adhesive strength of molten salt platinum have performed extremely well. The necessary resistance of the substrate to chemical attack is achieved using titanium or niobium. Since these metals passivate, however, electrocatalytic function and permanent contact property must be safeguarded by the platinum coating. Here the unique lack of pores and freedom from cracks of HTE platinum make a decisive contribution. In addition, the enormous electrochemical corrosion resistance is achieved by the extraordinary purity of more than 99 % platinum in the layer. Especially as contact materials, the refractory metals coated by means of the HTE process can show their special qualities to advantage. In the corrosive production processes of printed circuit board and semiconductor plating, they have proved their exceptional position meeting the highest standards of quality. During the lecture, both application examples were described in detail and illustrated by pictures. For further information please contact Mr. Thomas Ebert.

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