Submicron writing by laser irradiation on metal nano-particle dispersed films toward flexible electronics

The requirement for microwiring technology by a wet process has significantly increased recently toward the achievement of printable and flexible electronics. We have developed the metal microwiring with a resolution higher than 1 mu m by the laser direct writing method using Ag and Cu nano-particle-dispersed films as precursors. The method was applied to the microwiring on a flexible and transparent polymer film. The metallization is caused in a micro-region by focused laser beam, which reduces the thermal damage of the flexible polymer substrate during the metallization process. The laser direct writing method is based on the efficient and fast conversion of photon energy to thermal energy by direct excitation of the plasmon absorption of a metal nano-particle, that is, nano-heater effect of metal nano-particle. It provides Cu microwiring with a low resistivity owing to the inhibition of the surface oxidation of the Cu nano-particle.