An Advanced Selective Metallisation Process for PTH Manufacture

The Geislingen research laboratories of Dr Ing. Max Schlötter have developed Slotoposit, a new and advanced process for the manufacture of high quality PTH circuits, using conventional subtractive techniques. The aim of the research was to remove the hazardous formaldehyde present in most electroless copper systems, to improve hole wall adhesion and process the boards in one plating operation rather than the two (panel and pattern) employed in the traditional system. The following paper describes how a stable electroless nickel has been developed to achieve these ends and to increase productivity significantly by reducing the process steps and times.