Product Code: ICA11_M804

Laser-Based Manufacturing of Metallic Conducting Paths
Authors:
Christian Vedder, Fraunhofer Institute for Laser Technology (ILT); Aachen Germany
Jochen Stollenwerk, Fraunhofer Institute for Laser Technology (ILT), RWTH Aachen University; Aachen Germany
Norbert Pirch, Fraunhofer Institute for Laser Technology (ILT); Aachen Germany
Konrad Wissenbach, Fraunhofer Institute for Laser Technology (ILT); Aachen Germany
Presented at ICALEO 2011

Large-scale OLEDs, solar cells or heated windows have in common that they all are in need of conducting paths for collecting or distributing electricity on poorly or non-conducting surfaces.
But common techniques for the production of conducting paths in OLED devices are time- and energy-consuming and therefore expensive since they include high vacuum sputtering and photolithographic processes: More than 90% of the carefully applied metal coating has to be removed in an etching process leaving used etchants for recycling. Common solar cells conducting paths are made by screen-printing a silver paste onto the surface and then treating the applied structure in an energy-consuming furnace process.
The Fraunhofer ILT in cooperation with Philips Lighting developed a laser-based process to write metallic conducting paths of widths down to 35 µm onto ITO-coated glass (which also works for other flat surfaces such as plain glass, silicon wafers etc.) with speeds of up to 2.5 m/s at ambient air. The conducting paths consist of aluminium, copper, silver or a similar material and show specific resistances of about 0.047310-4 Ohmcm and sheet resistances of about 0.04 Ohms per square which is sufficient for OLED applications. A multiple coating will reduce resistances even further.