Product Code: ICAL09_M902

Depth Selective Laser Scribing of Thin Films for Roll-to-Roll Production of Silicon Solar Cells
Authors:
Jochen Löffler, Energy Research Center of The Netherlands (ECN); Petten Netherlands
Laurie Wipliez, Energy Research Center of the Netherlands; Petten Netherlands
Martijn De Keijzer, Energy Research Center of the Netherlands; Petten Netherlands
Johan Bosman, Energy Research Center of the Netherlands; Petten Netherlands
Wim Soppe, Energy Research Center of the Netherlands; Petten Netherlands
Presented at ICALEO 2009

Significant cost reductions for thin-film silicon solar cells are expected from a transition to roll-to-roll production. However, in contrast to state-of-the art batch-type fabrication of glass based products, for thin-film photovoltaic modules on foil substrates no standard processes for one essential production step the monolithic series interconnection - are presently available. Laser scribing is the preferred technology here as it allows fast, non-contact, local and precise removal of the thin films. In this contribution, we present the latest status of our process development on nanosecond pulsed lasers with three different wavelengths to achieve depth selective scribing of flexible thin-film silicon solar cells. To gain more insight into the selectivity of the process, the ablation thresholds of the different layers have been determined. Then, continuous lines were scribed by systematically varying the pulse energy and spot overlap. The required depth selective scribes could be obtained with all employed lasers (wavelengths of 355 nm, 532 nm, and 1064 nm). Currently, the electrical testing of the achieved scribes in working solar cells is in progress. First promising results have been achieved, and in a next step, fully series interconnected PV modules will be manufactured according to the presented device processing concept.