Interfacial reaction of reballed BGAs under isothermal aging conditions

Reballing involves removing the original solder balls and attaching new solder balls on the pads of ball grid array components. In this study, 676 I/O BGAs with Sn3.0Ag0.5Cu (SAC305) balls were reballed with eutectic tin-lead solder. The original metallization of the pads on the BGAs was Cu/Ni with immersion Au. Two solder ball removal methods were applied: the low-temperature wave solder method and the solder wick method. The preform solder ball re-attachment method was used to attach new solder balls. The components were investigated after the solder ball removal and solder ball re-attachment procedures. In comparison with non-reballed BGAs, the components using low-temperature wave solder method had phase change in the interfacial IMC layer, while the components using solder wick method had no phase change. Isothermal aging was used to investigate IMC growth and IMC composition change. There was no phase change in non-reballed and reballed BGAs after isothermal aging.