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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.

AA6061-T4 composites containing SiC and B4C particles were fabricated by friction stir processing (FSP) with an SKD11 tool. The microstructures and mechanical properties of the composites were investigated with various test methods. With the inclusion of ceramic particles, refined grains in the stir zone (SZ) were observed using a scanning electron microscope (SEM) and tunneling electron microscope (TEM). Because the ceramic particles facilitated grain refinement in the SZ via the pinning effect, the SZ with the particles had a much smaller grain size than the SZ without the particles. Vickers hardness test, tensile test and Charpy impact test were conducted to evaluate the mechanical properties. Mechanical properties of the SZ with the ceramic particles were improved relative to those of the SZ without the particles. Vickers hardness (from 50 to 90 HV), tensile strength (from 117 to 253 MPa) and Charpy impact absorbed energy (from 4.2 to 5.6 J) of the SZ increased with the addition of ceramic particles.