Microstructure and electrical property of laser-sintered Cu complex ink

We show that highly conductive Cu films are obtainable from Cu complex ink by laser sintering. The Cu inks, synthesized using Cu formate as a precursor, were spin-coated onto polyimide substrate and scanned by an ultraviolet laser at 355 nm. The blowing of N2 gas into the irradiated area prevented the film from being oxidized and a minimum resistivity of 1.70 × 10−5 Ω cm was obtained. The laser-sintered film, composed mainly of nanorods, exhibited a much tighter structure than the one achieved by the typical thermal process. Although the thermal-sintered Cu film had a better crystalline quality, the minimum resistivity values available with both methods were almost identical. This is attributed to the more compact microstructure induced by laser sintering.