Abstract
The conductive Cu nano ink can be printed by ink-jet printing on polyimide substrate, and then photo-sintered in the air atmosphere within 1 second. In the present work, the spin coated Cu nano ink on polyimide substrate was photo-sintered under various conditions. The microstructures of the sintered Cu films were observed by scanning electron microscopy. Neck formation and grain growth were promoted with increasing of irradiation energy. The mechanism of the photo-sintering process is studied in comparison with a firing process in nitrogen atmosphere. The obtained Cu film by photo-sintering process has low resistivity of 3μΩ·cm and good adhesion vs. polyimide. In contrast, the sintered Cu film by firing process in nitrogen atmosphere has high resistivity of 15μΩ·cm and poor adhesion. It was suggested that good adhesion between Cu film and polyimide is contributed by the bite into the substrate.
