Formation and growth of intermetallic compound layers at the interface during laser soldering using Sn-Ag Cu solder on a Cu Pad

The formation and growth of an intermetallic compound (IMC) layer at the Sn-Ag-Cu solder/Cu interface after laser soldering and during isothermal aging were investigated to elucidate the basic characteristics of the laser soldering process. The impact reliability of joints soldered using the laser process was also examined. It was found that, in the as-soldered condition, a relatively thin IMC layer is formed at the interface of the joints soldered by the laser process. The impact reliability of the joints soldered by the laser process at 20 W for 40 s was superior to that of the joints soldered by the conventional reflow process.