Characterization of copper conductive ink for low temperature sintering processing on flexible polymer substrate

Printed interconnects on flexible substrates using copper nanoparticles ink is attractive because of its lower material cost, lower electrical resistivity and higher electromigration resistance as compared to gold or silver-based ink. However, Cu nanoparticles oxidize easily during the sintering process, which has an adverse effect on its quality and reliability. Thus, it requires process modifications such as sintering in an inert environment to reduce the oxidation effects. In this paper, the properties of nano-sized Cu particles ink-jet printed conductive films that were sintered in N₂ environment are investigated. The sheet resistance and microstructure of the Cu films were monitored as a function of temperature.