Growth kinetics of the intermetallic phase in diffusion-soldered (Cu-5 at.%Ni)/Sn/(Cu-5 at.%Ni) interconnections

Abstract A stereological analysis was carried out in order to obtain the kinetics parameters of the (Cu 1− x Ni x ) 6 Sn 5 growth in the diffusion soldered (Cu–5 at.%Ni)/Sn/(Cu–5 at.%Ni) interconnections where previously anomalous fast growth of this phase was described. The n -parameter in the equation x  =  kt n was found to be 0.27–0.15 in the temperature range 240–260 °C, respectively. This is far away from the volume control process ( n  = 1 if total surface of forming phase is the reference). The TEM/EDX microanalysis made across the (Cu 1− x Ni x ) 6 Sn 5 /Sn – solder showed sudden change of Sn and Cu content typical for the grain boundary diffusion as the rate controlling mechanism.