Laser systems for solar cell manufacturing

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Rofin recently showcased five examples from its comprehensive range of technologies for solar cell manufacture, covering thin film and crystalline silicon (c-Si) technologies as well as volume production and research. Rofin offers the world‘s broadest range of laser sources for edge deletion applications. The company states that its 800W DQ x80 system has been established as the top-selling laser for edge deletion of thin film cells. Furthermore, the new PowerLine L 400 covers the lower end of the spectrum. Using an optimised resonator design, which significantly increases output power, this laser source replaces the PowerLine L 300. Optimised square fibres are available for both lasers. Compared to round fibres, square fibres provide highest efficiency, machining a larger area per pulse and enabling consistent overlap of individual pulses.

Wafer marking in solar cell manufacturing is the key to traceability and improved manufacturing processes. DataMatrix codes may be used on solar active areas, but they are prone to deteriorate in the multitude of coating and etching processes. Using the new ECCI code, Rofin present a potential solution. Unlike ECC DataMatrix codes, this code is highly resistant to the changes in contrast often found on heterogeneous surfaces such as polycrystalline solar cells. As long as something is visible decoding works - even in case of contrast inversions within the marking. Additionally, ECCI code redundancy is adjustable. Marks which might be subject to heavy wear and tear can use a highly redundant coding.