Low Temperature Sintering-bonding with Cu NPs for Electronic Packaging Application

摘要

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. In recent years, significant progress has been achieved using Ag nanoparticles (Ag NPs) as Pb-free electronic interconnection materials. 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 Cu nanoparticles (Cu NPs) as bonding material. The results of our investigations revealed that bonding between Cu wires and Cu pads can be accomplished at the temperature lower than 200°C in air atmosphere. The Cu nanoparticles (Cu NPs) were synthesized prepared by a reduction chemical reaction. The polymer that coated on the Cu NPs can protect the CuNPs from oxidation. The sintering-bonding was formed by sintering of Cu NPs through neck growth and direct metallic bonding between Cu-Cu interfaces. The tensile-shearing test of joints showed that strength up to 10 MPa was achieved. This novel sintering-bonding technology using Cu nanopaste as interconnection material has a potential application in the electronic packaging industry.