Active soft solder deposition by magnetron-sputter-ion-plating (MSIP)-PVD-process

Abstract

In different technical areas micro electro mechanical systems (M.E.M.S.), e.g. micro pumps, micro sensors, actuators and micro dosage systems are in use today. The components of these M.E.M.S. consist of various materials, which have to be joined. To join materials like ceramics, plastics or metals to a hybrid M.E.M.S., established joining technologies have to be adjusted. For the assembling and mounting of temperature sensible micro components, a low temperature joining process, e.g. transient liquid phase (TLP) bonding or an active soft soldering process can be performed. In this article the deposition of a low melting active soft solder by magnetron-sputter (MS)-PVD deposition with an active substrate cooling will be presented. The substrate temperatures were set and controlled by an additional cooling unit, which was integrated into the sputtering facility. In the performed experiments a substrate temperature range from −40 to +20 °C was investigated. The effects of these different substrate temperatures to the microstructure and the soldering suitability of the solder system were investigated by scanning electron microscopy (SEM), nanoindentation and soldering tests. The chemical composition of the deposited solder systems was examined by glow discharge optical spectroscopy (GDOS)-analysis. As a suitable substrate temperature range for deposition −10 to −20 °C was detected. Solder systems deposited in this temperature range showed good solder abilities.