AL/NI multilayer used as a local heat source for mounting microelectronic components

This paper describes a novel local heating technique for microelectronic mounting. Aluminum/nickel (Al/Ni) multilayer foils show self-propagating exothermic reactions, driven by a reduction in atomic bond energy which can provide rapid bursts of heat and can act as a local heat source to melt solder layers and join materials. In this work, we demonstrate the validity of the Al/Ni reactive foils as a heat source in microelectronic mounting by joining a tiny sheet coppers to a printed circuit board. The Al/Ni multilayer was made by cooled rolling. Thermal analysis of the exothermic reactions in Al/Ni multilayer films was made to make sure that the bonding process is feasible theoretically. The interface of the bonding and the reaction product of the reactive Al/Ni foils was characterized by using Scanning Electron Microscope (SEM) and Energy Dispersive X-ray Detector (EDX).