Silver Sintering at Low Temperatures Without Using Pressure: An Approach for Joining Large Area Copper-to-Copper Interconnects

Abstract:
Low-temperature nanosilver sintering has been widely discussed as a promising method to replace traditional lead solders. Superior results were reported when external pressure was used. When trying to eliminate the use of pressure, a new kind of nanosilver paste is necessary, and the temperature and time parameters are then more central in sintering. In this paper, the performance of a new type of nanosilver paste for pressureless sintering was examined. The temperature and time dependence of the thermal decomposition of the organic component was studied as well as the impact on the atmosphere of their gaseous products. The effect of different lengths of holding time on microhardness was evaluated. Shear tests were performed on bare copper, silver, and gold metallized surfaces of three dimensions and were joined at different temperatures. Finally, resistivity was measured on self-standing specimens sintered at different temperatures.