Materials modification of the lead-free solders incorporated with micro/nano-sized particles: A review

Abstract

As to promote the performance of the solder joints applied to electronics industry, the researchers take advantage of micro/nano-sized particles or another element coated on nanoparticles to be incorporated into the solder paste or flux and investigate their microstructure and properties. Based on refinement strengthening and dispersion strengthening theory, it was reported that introducing nanoparticles into the solder could significantly refine the matrix of the solder, improve the wetting ability and strengthen the mechanical performance of the solder joints. In this review, the influence and mechanism of varying sizes and contents of the metallic particles, intermetallic compound particles, metal oxide particles and carbon nanoparticles on the structure and performance of the solder is comprehensively summed up. Subsequently, the influence of nanoparticles on the melting temperature, wettability, microstructure, mechanical evolution, creep behaviors, electromigration properties and reliability of the solder has been summarized. Furthermore, the effect of micro-sized particles addition to solder alloy in 3D packaging also has been sketched out. Finally, the shortcomings of nanoparticle reinforced lead-free solder are put forward in order to provide a theoretical basis for the future development of particle-reinforced solder with excellent properties.

Keywords

• Solder joints
• Electronics industry
• Micro/nano-sized particles
• Properties
• Reliability
• Reinforced