Room-temperature interconnection of electroplated Au microbump by means of surface activated bonding method

Although various bonding methods have been developed for flip-chip assembly, most of them cannot be applied to smaller pitch interconnection for the next generation. In the present study, a new bonding method, the surface activated bonding (SAB) is introduced. The feasibility of the SAB for bump bonding was investigated by some experiments. The Au electroplated bumps were prepared for experiments. The three different types of material, Au, Cu, and Al were used as contact metals. The reliability of interconnections was tested in temperature storage. As a result, we could achieved the bonding of microbumps with high strength and good electrical connection. It was also found that in the case of bump bonding, SAB can be done under relatively high vacuum pressure condition.