EFFECTS OF METALLIC NANOPARTICLE DOPED FLUX ON INTERFACIAL INTERMETALLIC COMPOUNDS BETWEEN LEAD FREE SOLDER BALL AND Cu SUBSTRATE

摘要

This work investigates the effects of metallic nanoparticle doped flux on the morphology and growth of interfacial IMC layers. Four different metallic nanoparticles (Ni, Co, Mo and Ti) were investigated by incorporating them in a water soluble commercial flux on a copper substrate. It was observed that Ni and Co doping was found to transform the IMC from a typical scallop type to a planer type along with lowering the IMC thickness. These effects were suggested due to the in-situ alloying of these elements. Mo and Ti nanoparticles doped flux did not exhibit any alloying effect during reflow. Scalloped type morphology of IMC layer was retained in both these cases. This paper thus suggests a novel method of in-situ targeted alloying at the solder/substrate interface through the use of Ni and Co nano-doped flux for controlling the morphology and growth of IMC layers.