System for processing PERC cells

Chemnitz, Germany - 3D-Micromac AG has developed a novel, highly productive laser system for opening the rear sides of PERC cells. The system is modular, combinable with different laser-source technologies, and achieves a typical efficiency increase up to one percentage point.

3D-Micromac AG's new structuring system opens rear-side-passivated cells (PERC, passivated emitter rear contact). PERC cells are photovoltaic cells made of crystalline silicon having special, optimized rear-side passivation. A PERC cell's rear side is completely coated with a nonconductive, dielectric SiOx/SiN or AIOx/Sin layer. The task is to open this layer with the aid of point or line patterns using lasers without damaging the underlying silicon in order to later apply a metal layer for contacting.

With this system, elaborate handling and individual positioning procedures of the cells are eliminated. The cells are now transported under the laser source on a conveyor belt, which renders alignment stops superfluous. The integrated optics automatically compensates for the cells' relative motion and scribes exactly the desired pattern into the cell's sensitive rear side.

The system is being initially offered as a stand-alone variant; however it can also be completely integrated into existing production automation.

In addition to manufacturing PERC cells, the structuring platform from 3D-Micromac is also suitable for processing of selective-emitter, MWT, and EWT cells.