Low temperature bonding process using mixed Cu-Ag nanoparticles for electronic packaging

The lead and its compounds can bring harm to natural resources and human health. It is necessary to develop new bonding method using Pb-free material as an alternative to Pb-bear solder for microelectronic packaging. During the past few years, much attention has been paid to low temperature bonding technology using Ag nanoparticles (Ag NPs). However, packaged joints with Ag NPs are accompanied with some disadvantages such as high cost, high ionic migration. In this study to overcome the mentioned problems, we investigate a new low temperature sintering-bonding technique utilizing mixed Cu-Ag nanoparticles (Cu-Ag NPs) as bonding materials. The Cu nanoparticles (Cu NPs) and Ag nanoparticles (Ag NPs) were prepared by chemical reduction method respectively. The Cu-Ag NPs were prepared by mixing Cu NPs and Ag NPs. Our experiment showed that strong joints were obtained using Cu-Ag nanopaste at 200°C in air atmosphere. This novel sintering-bonding technology using Cu-Ag NPs as interconnection material has a potential application in the electronic packaging industry. Copyright © 2011 MS&T'11®.