Thermal property measurement of solder joints fabricated by self-propagating exothermic reaction in Al/Ni multilayer film

To realize the application of reactive joint process to electronic packaging, we analyze thermal resistance for solder joints fabricated by using Al/Ni self-propagating exothermic reaction. Laser flash method with response function analysis is used for thermal resistance measurement. The specimens with 4-8-mu m-thick Sn-3.5Ag solder joint have thermal resistances ranging from 5.0 x 10(-6) to 8.1 x 10(-6) m(2) K/W. In the specimen with 12-mu m-thick SnAg solder joint, periodical heating analysis suggests that high and low thermal resistance areas happen to coexist due to incomplete bonding. Micro thermo-reflectance (m-TR) analysis suggests that thermal effusivity of reacted NiAl layer is lower than expected. Thermal resistance of the joints will be influenced by voids, cracks, and grain boundaries in reacted NiAl layer. (C) 2015 The Japan Society of Applied Physics