Development of Advanced Lead-Free Solder Based Interconnect Materials Containing Nanosized Y₂O₃ Particulates

This study addresses the development of lead-free nanocomposite solders. Lead-free composite solders were successfully synthesized, with varying amount of nanosized Y₂O₃ particulates incorporated into 95.8 Sn - 3.5 Ag - 0.7 Cu solder. These composite materials were fabricated using the powder metallurgy technique involving blending, compaction, sintering and extrusion. The extruded materials were then characterized in terms of their physical properties, microstructural development, thermal and mechanical properties. Results revealed that with the incorporation of increasing amount of reinforcements, the density values of the composite solders decreased while their corresponding porosity levels increased. Thermomechanical analysis of the solder nanocomposites showed that the use of reinforcements lowered the average coefficient of thermal expansion of the solder materials. Moreover, the results of mechanical property characterizations revealed that the addition of reinforcements aids in improving the overall strength of the nanocomposite solder. Particular emphasis is placed in this study to correlate the effect of increasing presence of Y₂O₃ particulates with the properties of the resultant nanocomposite materials. These advanced interconnect materials will benefit industries like the microelectronics flip chip assembly and packaging, MEMS systems and NEMS systems.