Reaction dynamics of CWAr+ laser induced copper direct writing from liquid electrolyte on polyimide substrates

Conductive copper patterns were deposited on polyimide (PI) surfaces using a focused, scanned CW Ar+ laser beam at 488-nm wavelength. The deposition process was initiated by a photothermal reaction of a tartarate-complex solution of Cu2+ ions in an alkaline and reducing medium. Deposits were characterised by Field Emission Scanning Electron Microscope (FESEM), Energy Dispersive X-ray Spectrometry (EDS) and resistance measurements. The mass of the deposited copper (m(Cu)) and also the rate of the deposition (dm(Cu)/dt) were calculated from the resistance measurements, The dependence of the copper deposition rate on the scanning speed of the laser beam, number of scans, laser power and the temperature of the solution were examined, It was found that more chemical reactions were running parallel during the direct writing process yielding metallic copper and copper(II)-oxide on the PI surface. (C) 2000 Elsevier Science B.V. All rights reserved.