A Novel Resistance Measurement Methodology for $In~Situ$ UBM/Solder Interfacial Reaction Monitoring

This article presents a methodology to investigate, in situ, the interfacial solid-state reaction of alternative metallurgical systems, such as Cu/Ni/Sn and Ni/Cu/Sn bumps. The methodology is based on continuous in situ resistance measurements as a function of time and temperature. It allows to extract solid-state interfacial kinetic reaction parameters, such as activation energy and power factor, in a much more precise and faster way than the conventionally used methods. Moreover, the continuous recording of resistance change makes comparing different metallurgical systems easier. This article shows the results obtained using this method for Cu/Ni/Sn and Ni/Cu/Sn.