Electromigration Behavior of Sn58Bi and Sn58Bi Epoxy Solder Joint

Abstract

As demanding for high performance and miniaturization of electronic devices, interconnection materials required higher reliability in mechanical, thermal and electrical. The importance of electromigration issue has increased because of these trends. We evaluated the electromigration behavior of Sn58Bi solder and Sn58Bi epoxy solder under high temperature and constant current flow. The electromigration test-kit was a designed and fabricated flip chip-type module and the diameter of the solder bump was 250 μm. A current was passed through the two solder joints, producing a current density of 3.0 × 103 A/cm2 at 100 °C. The microstructure of solder joint after electromigration test were investigated with field-emission scanning electron microscopy during electromigration, a Bi-rich layer was observed at the anode side of the solder joint and the formation of Kirkendall voids was observed at the cathode side of the solder joints. Different inorganic materials affect electromigration in the eutectic Sn58Bi solder joints.