Study on interfacial reaction behavior of Sn[sbnd]Ag based lead-free solder with (111) single crystal copper substrate

Abstract

The morphology and crystal orientation of intermetallic compounds formed by the reaction between SAC305 solder/(111) and SABI333 solder/(111) single crystal copper substrate were investigated. The morphology of Cu6Sn5 at the interface of SAC305 solder/(111) single crystal copper substrate changes from scallop to prismatic with the increase of reflow time. The Cu6Sn5 grains grow parallel to the horizontal direction of the Cu substrate and grow along the vertical direction, and there is an Angle of 60° between different Cu6Sn5 crystals. The calculated b ~ t0.23 relation satisfies the growth kinetics of prismatic Cu6Sn5. In addition, the morphology of Cu6(Sn, In)5 at the interface of SABI333 solder/(111) single crystal copper substrate is between scallop-type and prismatic-type. Cu6(Sn, In)5 grains grow at a certain angle with a single crystal copper substrate due to the addition of In element. Furthermore, it is considered that the deflection mechanism of Cu6(Sn, In)5 grains is controlled by the length and strength of inter-atomic bonds within the grains after the In atom substitution reaction.