Monolithical Serial Interconnects of Large CIS Solar Cells with Picosecond Laser Pulses

The production of CIS thin film solar cells is still employing some mechanical steps of structuring, where thin layers have to be selectively separated in three patterns (P1 to P3) for the monolithic serial interconnection. We report on the high speed structuring of these patterns by picosecond laser ablation at 1064 nm. We demonstrate on 100x100 mm2 samples, that the molybdenum back electrode can be structured with a process speed of up to 15 m/s. The ZnO front electrode film can be line separated with up to 15 m/s, the CIS absorber layer is structured with up to 4 m/s. Furthermore we extended our laser processes to 300 x 300 mm2 pilot line samples which were displaying efficiencies of 13.4%.