Recent Advances in the Synthesis of Lead-free Solder Nanoparticle

Particles in the nano-meter size range present extraordinary properties, such as, large surface area per unit volume, large surface energy, low melting point, supermagnetism, self-purification and quantum size effects. These properties have attracted the attention of scientific and technological communities al over the world. In the area of electronics production, one major disadvantage of conventional lead-free solders is their relatively high melting temperatures. Higher melting temperatures result in higher reflow temperatures which in turn result in stress build-up and other defects occurring during reflow. The possibility to lower the melting temperature of solder alloys and to improve the mechanical properties of solder joints by decreasing the particle size to the nanometer range, has therefore, offered a potential solution to these problems. Nanoparticles of different solder alloys have, therefore, been manufactured using both top-down and bottom-up techniques. This paper presents the latest developments in the area of lead-free solder nanoparticle's manufacturing. Both the manufacturing and characterization of solder nanoparticles are covered. This paper does not include, however, applications of such nanoparticles. Both work performed in our group and in other research groups, from all over the world, is included, and the results discussed.