The phase and intermetallic thickness of Cu-Zn₅ and Cu₅Zn₈ has been investigated under liquid state aging using reflow method. Both the intermetallic was formed by reacting Sn-9Zn lead free solder with copper substrate. Scanning electron microscope (SEM) was used to see the morphology of the phases and energy dispersive x-ray (EDX) was used to estimate the elemental compositions of the phases. The morphology of the Cu₅Zn₈ phase was rather flat but when the soldering temperature and tine increases, the morphology becomes scallop. Intermetallic thickness measurements show that the thickness of the Cu-Zn₅ decreases with increasing soldering time and temperature. Whereas, the thickness of the Cu₅Zn₈ intermetallic increases with soldering time and temperature.
