Laser Scribing

Production of precision insulation channels on thin-film solar cells

In principle the process of laser scribing is based on the laser-induced removal. The laser creates micrometer precision insulation channels for optimum utilization of the substrate-surface, while not damaging the material under the silicon film. This makes lasers the most accurate tool on the market for scribing thin-film solar cells. This accuracy and precision produces high efficiency solar moduls.

Various thin-film technologies use starting substances: Transparent conductive oxides (TCO) as front electrodes, cadmium telluride (CdTe) as well as amorphous silicon (aSi) and microcrystalline silicon (aSi / μSi) as semiconducting films, and metals, e.g. molybdenum (Mo) as rear contact.

For application of the electrode and the semiconducting coatings, the films between the successive coating processes are separated into insulating strips by the process steps P1, P2 and P3. In the illustration, a conductive path between the front electrode of one cell and principal buildup of a thin rear electrode of another cell is created between adjacent strips, film solar cell, or cells, resulting in the connection of both cells in series.

LPKF Allegro laser systems are exceptionally suitable for laser scribing of ultra-thin-films: Different laser sources with varying wave lengths are used to selectively remove the utilized layers of thin-film solar cells while preventing damage to each underlying layer.