Search results

The microstructure of the Sn‐3.5wt%Ag/Cu and Sn‐9.0wt%Zn/Cu interfaces after soldering at 250°C was evaluated. The cross‐sections were investigated using a scanning electron microscope and energy dispersive X‐ray to determine the interface layer structure and composition. Even though the cooling rate from soldering temperature to room temperature is rapid, this study indicates that the intermetallic compound is formed at the interface between the solder and the copper substrate for both the Sn‐3.5wt%Ag and the Sn‐9.0wt%Zn lead‐free solders.