Characterization of reactive nano scale multilayer foils for microsystem applications

A new joining process that is based on reactive nano scale multilayer foils can form a metallic bond between different wafers or chips and is therefore of interest for different micro system applications. The bonding process is based on a self propagating exothermic reaction within the foil and allows bonding the components at room temperature supported by additional solder films. In this paper, nano scale multilayer films of aluminum (Al) and titanium (Ti) were magnetron sputter deposited on different substrates like glass or silicon wafers. The reaction of the Al/Ti multilayer system was initiated by thermal or laser activation and investigated with the help of a thermography camera. The aim of this study was to characterize the microstructure and the quality of the single layers by high resolution electron microscopy methods and ToF-SIMS analysis.