Sintering Of Hybrid Nano Sliver Paste Achieve Cone-Structured Cu Bonding in die attachment

摘要

In this paper, towards to the problem existed in sintering of nano sliver paste used in electronic packaging devices, we take corresponding measures and achieved very good results. Nano silver paste, because of its low-temperature sintering characteristics, is generally considered as a substitute for lead-free solder for high temperature applications. There still exist some serious problem in the sintered sliver paste die attachment, which limit its application in production. For example, high porosity and voids, poor wettability at interfaces, which decrease thermal and electrical conductivity and mechanical strength of the sintered join, breaks often occur at the interface between copper and sintered silver. We adopt electroless plating method growing copper cones on copper, and its surface morphology were characterized by Scanning Electron Microscope. Copper cone structure increase contact surface with sliver particle and forming mechanical interlock. For improve the wettability and reduce voids, we plus low melting point material tin to sliver paste to prepare hybrid nano sliver paste. This study aims at address these issues and concentrates on mechanical and microstructural characterizations of the attachment. Experiment shows that, Cu cone together with hybrid sliver paste had achieved an remarkable bonding interface and bring this technology much closer to practical use for high temperature and high power applications.