Growth of Cu-Sn intermetallic compounds during isothermal aging processing in electroplated Cu/Sn/Cu system

摘要

Microstructure evolutions of as-reflowed and aged electroplated Cu/Sn/Cu sandwich structure with 20 or 40μm Sn layer have been investigated. Cu3Sn was observed at lower side of Cu/Sn/Cu structure with 40μm Sn layer after isothermal aging treatment for 24 hours, as for that structure with 20μm Sn layer, Cu3Sn appeared after aging for 48 hours. Regardless of Sn volume, the thickness of the blanket Cu6Sn5 and total intermetallic compounds (Cu6Sn5+Cu3Sn) increased linearly with the increasing aging time. After long-time aging processing, the layers of blanket Cu6Sn5 and Cu3Sn in the the Cu/Sn/Cu structure with 20μm Sn layer are both thicker. Volume of Sn layer has significant effect on the growth of Cu-Sn IMCs in the electroplated Cu/Sn/Cu system.