Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : March 07, 2022 - March 08, 2022
Metal printing technique has attracted attention as a promising manufacturing method. To date, Cu patterning with high electroconductivity has been achieved by laser-reduced thermochemical precipitation in air using glyoxylic acid Cu complexes. However, it is difficult to fabricate thick Cu patterns due to their large volume shrinkage. In this study, we investigated the patterning properties of femtosecond laser patterning using a glyoxylic acid Cu (GACu) complex/Cu nanoparticle mixed ink. The Cu nanoparticle ink film was prepared by spin-coating a Cu nanoparticle ink on a glass or polyethylene naphthalate (PEN) substrate. Next, glyoxylic acid Cu complex ink was spin-coated onto the Cu nanoparticle ink film to produce glyoxylic acid Cu complex/Cu nanoparticle mixed ink film. After that, direct writing using green femtosecond laser pulses was performed in air. The wavelength, pulse duration, and repetition rate of the laser were 515 nm, 100 fs, and 40 MHz, respectively. The laser pulses were focused onto the samples using an objective lens with a numerical aperture of 0.45. The height of Cu pattern was 5.2 μm by single-scanning of the focused laser pulses. X-ray diffraction spectra showed the peaks corresponding to Cu on the both glass and PEN substrates. The resistance of the patterns was lower than that of the glyoxylic acid Cu complex ink. These results indicate that the Cu nanoparticles mixed with the GACu complex ink improved the density of the patterns with high film thickness. Such direct writing technique is expected to be used for fabricating flexible devices.
