Investigation of Cu6Sn5 Grain Orientations in Sn3.0Ag0.5Cu Lead-Free Solder Joints on Cu Sigle Crystal Substrates

Electron backscatter diffraction (EBSD) technology combined with Orientation Imaging Microscopy (OIM) analysis method were employed to investigate the morphologies and orientations of Cu₆Sn₅ grains formed between Sn3.0Ag5.0Cu and (001) (111) Cu single crystals under liquid-state condition. The results show that the reflow temperature was the main factor that influence the transformation of Cu₆Sn₅ grains from scallop-type to prism-type. The morphology for. the prism-type Cu₆Sn₅ grains formed on Cu single crystals arranged regularly, and their orientations had a strong dependence on the Cu substrates, the reason for which is the low misfit leading to the decreasing of surface energy.