Scanning Nd:YAG laser system for industrially applicable processing in silicon solar cell manufacturing

In order to demonstrate different laser beam processes for solar cell manufacturing a state of the art high power scanning laser system has been installed at ´Fraunhofer ISE´. The high potential of laser beam techniques is mainly based on the contactless operation, making them suitable for fragile silicon wafers, and their in-line suitability. Besides, the laser process can be accurately controlled and hence, a perfect reproducibility is obtained even at high pulse repetition rates. Combined with the feed speed of the scanned laser beam of up to 10 m/s this allows short process times as necessary for industrial throughput. Laser beam applications that are presently under investigation are first the ´laser-fired contacts´ (called LFC), a technique for implementing the rear contact of dielectric passivated solar cells, and second ´laser edge isolation´ (called LIS).