B添加延性Al/Ni多層膜によるクラックレス接合技術

抄録

Al/Ni multilayer film is attractive because the film is able to show self-propagating exothermic reaction by applying very small energy. We are using the film as a heat source for soldering Si wafers. However, many cracks are introduced into reacted NiAl layer after reactive bonding because the exothermic reaction of Al/Ni multilayer film with atomic content ratio of 1:1 for Al and Ni involves volume shrinkage by 12% based on crystal structure change. Cracks in bonded section cause mechanical degradation and thermal resistance elevation, so that these should be reduced as much as possible. To reduce the number of cracks in bonded section, it is considered that reacted NiAl layer is made more ductile. In this work, we focus on investigating the ductility of reacted NiAl originating from B-doped Al/Ni multilayer film by means of cantilever bending test. The effect of B-doping is discussed on the basis of cross-sectional SEM observation result after exothermic reaction.