| abstract |
Fine wirings are made by a method having the steps of painting a board with metal dispersion colloid including metal nanoparticles of 0.5nm-200nm diameters, drying the metal dispersion colloid into a metal-suspension film, irradiating the metal-suspension film with a laser beam of 300nm-550nm wavelengths, depicting arbitrary patterns on the film with the laser beam, aggregating metal nanoparticles into larger conductive grains, washing the laser-irradiated film, eliminating unirradiated metal nanoparticles, and forming metallic wiring patterns built by the conductive grains on the board. The present invention enables an inexpensive apparatus to form fine arbitrary wiring patterns on boards without expensive photomasks, resists, exposure apparatus and etching apparatus. The method can make wirings also on plastic boards or low-melting-point glass boards which have poor resistance against heat and chemicals. |