Diode laser-assisted pyrolysis of organometallic films for the fabrication of metallic conductors on polyimide

We have developed a simple, compact, and inexpensive diode laser-assisted direct writing system for the fabrication of copper and gold interconnects on polyimide for repair and customization applications in the packaging industry. Gold-containing precursor films were prepared from a commercial organometallic solution. A thermochemical analysis of the precursor was conducted in order to understand its decomposition process. The diode laser-assisted pyrolysis of the precursor films produced conductive gold lines on polyimide with widths ranging from 12 to 60 μm, a thickness of 0.1 μm, and a minimum resistivity of 30 μΩ·cm. The deposits were annealed in air at 300°C in order to induce the activation of the electroless plating of copper. Cu/Au conductors, 2-μm thick, with an overall resistivity of 8 μΩ·cm were obtained after a 45 min immersion in the plating bath. Preliminary results concerning the diode laser-assisted pyrolysis of copper-containing organometallic films are also presented