An improved approach of synthesizing of Cu-Ag core-shell nanoparticles

With the development of high frequency and high power SIC devices, the requirement of high temperature connection materials between chip and substrate is becoming higher and higher. In recent years, the effects of the size of nanometer materials to achieve “low temperature bonding” research more and more. But the commonly used copper and silver are both disadvantages, easy oxidation of copper and silver high costs and electricity migration issues. So scholars began to study Cu-Ag core-shell nanoparticles, which has the advantages of copper and silver. But at present, the preparations of Cu-Ag core-shell nanoparticles are immature, there are some problems such as low yield, the uneven coating, process complex problems. In this study, a new method is applied in the fabrication of Cu-Ag core-shell nanoparticles. By adding L-histidine and ammonia water as a new complexing agent, the silver plating rate was controlled better than add ammonia alone. The as-prepared Cu-Ag nanoparticles show good coating quality, with core-shell structure and oxidation resistance. The new formulation provided in this study can be used to further rapidly prepare Cu-Ag coreshell nanoparticles for chip interconnection.