Laser induced writing of conductive copper lines for electronic devices

The direct writing of conductive copper lines on alumina substrates by means of a Nd/YAG-laser was investigated as an alternative to established thick-film and thin-film hybrid technology. Copper powder in the low micrometer range was sprayed as an aqueous dispersion on the surface of alumina substrates normally used for thick-film hybrids. With proper setting of the laser parameters, conductor lines with good adhesion and a relatively smooth surface were achieved. After removal of the excessive copper powder, the remaining copper particles acted as seeds for a subsequent electroless copper plating thus providing an electrical conductivity sufficient for electronic devices.