Abstract
Regarding effects of Electroless Nickel/Immersion Gold (EN/IG) on BGA solder joints, pull strength of solder balls on the substrates plated by several kinds of EN/IG were evaluated using hot bump pull test. Furthermore, each surface structure of EN and IG plating was observed by SEM/EDX and the interfaces of BGA joints were analyzed by EPMA. It was found that the process of EN producing low-phosphorous content deposit and IG plating that hardly deteriorated nickel surface was better for BGA solder joints. It seemed that BGA solder joint was destructed at the interface between Ni-P and Ni-Sn intermetalic layer.
