Investigation of intermetallic compounds (IMCs) in electrochemically stripped solder joints with SEM

In this work we compare the microstructures of intermetallic compounds (IMCs) in electrochemically stripped solder joints created by two different soldering methods (vapor phase soldering (VPS), and selective laser soldering with a CO2 laser). After the selective removal of the Sn phase with amperometry, the microstructure and structural composition of the IMC can be revealed in a detailed way, which is unlike any other previously published methods. The differences between the IMC microstructures of the technologically different solder joints were analyzed with optical microscopy and scanning electron microscopy (SEM). Energy dispersive spectroscopy (EDS) measurements were utilized to identify the different intermetallic phases (Ag3Sn, Cu6Sn5). Significant differences were observed in the IMC structures of solder joints prepared by different technologies.

► Microstructures of intermetallic compounds in solder joints were investigated with SEM. ► Electrochemical stripping was utilized to remove the tin phase from the solder joint. ► IMCs of vapor phase soldering and CO2 laser soldering were compared. ► Significant differences were found between the IMC microstructures.