3D-Micromac (Chemnitz, Germany), which supplies laser micromachining and roll-to-roll laser systems for the photovoltaic, medical device, and electronics markets, has installed three of its microCELL OTF laser systems at Hanwha SolarOne's production facility in Qidong, Jiangsu, China. Following the installation, Hanwha SolarOne placed an order for a fourth laser system to support the conversion of its aluminum back surface field (Al-BSF) technology production to high-efficiency passivated emitter rear contact (PERC) solar cells.

PERC solar cells have the potential to deliver a significantly higher level of energy efficiency compared to standard solar cells. A critical step in the manufacturing process of PERC solar cells is laser contact opening (LCO), where laser ablation is used to perforate a thin passivation layer onto the rear side of the solar cell. This process reduces electrical losses in the cell, resulting in approximately 1% (absolute) higher conversion efficiency.
The microCELL OTF laser platform features on-the-fly technology—a laser process that takes place while the wafer runs in continuous motion through the machine, boosting the throughput by eliminating dead cycles for motion encountered with competing approaches. The system achieves throughput values above 4000 wafers per hour (wph) with single-lane systems and above 8000 wph with dual-lane systems. 

The systems also offers contactless wafer handling, which holds the wafer in place on an air cushion during processing to reduce or eliminate surface defects and microcracks, enabling maximum yields. Mechanical wafer handling, on the other hand, can increase the likelihood of surface defects and microcracks occurring, which can result in additional wafer damage during subsequent process steps.

"The Chinese market is a highly competitive one, with a strong focus on pricing," says Tino Petsch, CEO of 3D-Micromac. "By providing high quality and yield, as well as cost dilution through the highest throughput values in our laser systems, we succeeded in being the first choice for the technology conversion at Hanwha's Chinese solar cell manufacturing plant." 

3D-Micromac's systems and services have been implemented in various high-tech industries worldwide.