Laser for More Capacity

Structuring without residue
On the other hand, during the manufacture of thin-film modules, lasers have already become established – “because it does not work any other way now,” says Alejandro Becker from laser specialists InnoLas. This is because the individual layers must be structured with very fine lines between the coating processes. This “patterning” normally takes place with nanosecond lasers in the case of thin-film silicon modules, confirms Stute. However, they are too slow to process the more efficient copper indium gallium (di)selenide (CIGS) modules. Therefore, picosecond lasers are used for this – with interesting results. This is because their light is not absorbed. Instead it causes a local and high-grade ionisation, explains Bernhard Klimt from Lumera Laser. A layer of several hundred atom layers, about ten to 100 nanometres thick, is consequently transformed into plasma, a gas, in an extremely short space of time. As a result, the laser does not leave behind any gratings or welding residue. “The structures are cleaner, much more precise,” emphasises Klimt. And the ultra-short pulse laser has another advantage: “With this laser, you can process any materials. You no longer have to look for a laser with the right wave length for each material.”

When you take a look at the global market, it is noticeable that the innovative German SMEs have an outstanding position here: In the field of laser technology, they dominate with a market share of 80 percent. However, competitors from the USA are also well positioned. They have subsidiaries in Germany which are strong in research.