Investigating micro-alloyed solder joints with electrochemical etching

In this paper micro-alloyed solders were investigated with a new technique of electrochemical material removal. The samples were soldered with low silver content and micro-alloyed solders and with SAC305 and SAC405. We could investigate the surface of the intermetallic layer by etching the tin based layer from the top of the intermetallic layer. From cross-sections, we also obtained data indicating that what kind of microstructure formed after the reflow process in the solder joints. We measured the thickness of the Cu₆Sn₅ intermetallic layer in each solder joints. After the etching process, we detected that the shapes of the formed Cu₆Sn₅ intermetallic layer were different in each samples.