In the new process developed by Fraunhofer ISE, a fine mesh screen receives fine laser structures that enable metallization paste to be precisely printed onto the solar cells using the flatbed screen printing process, as seen in this picture. (Photo Credit: Fraunhofer ISE /Andreas Lorenz) 
Technology

Fraunhofer ISE Unveils Laser System For Fine Mesh Screens

German institute introduces laser system, opening alternatives to Asia-exclusive laser structuring of fine mesh screens for solar cell metallization

Anu Bhambhani

  • Fraunhofer ISE-led Laser2Screen project has developed laser technology for ultrafine mesh screens 

  • It is a fully digital laser process that replaces UV exposure and chemical etching agents, which will make solar more sustainable 

  • It can help save silver during the metallization process and also increase the cell’s performance by reducing optical shadowing 

The Fraunhofer Institute for Solar Energy Systems ISE says it has developed a laser system that can precisely structure ultrafine wire mesh screens as thin as 5 µm, and metal stencils with openings as small as 2 µm. Fine mesh screens are essential for solar cell metallization; hence, this laser structuring of fine mesh screens becomes an important tool, something that currently takes place exclusively in Asia.  

“With this newly developed laser system, we at Fraunhofer ISE are, for the first time, able to structure high-precision fine mesh screens for resource-efficient solar cell metallization at the highest level of quality. In terms of structure sizes, we can even create structures down to the submicrometer range with this system,” said Group Leader for Printing Technologies at Fraunhofer ISE, Dr. Andreas Lorenz. 

Developed as part of the Laser2Screen project with its industry partner Pulsar Photonics GmbH, Fraunhofer ISE says the laser system is based on ultrashort pulse laser technology and precise 3D scanning technology. 

In the new system developed, the conventional manufacturing method of UV exposure of a photoreactive barrier layer is replaced by a fully digital laser process. This allows for flexible adaptation to workpiece variations and integrated optical measurement of the generated structures.  

Fraunhofer ISE says this sustainable laser technology eliminates the need for chemical etching agents or photoresists. 

The fine laser-structured openings in the contact save silver during metallization. These also increase the cell’s performance by reducing optical shadowing. 

“This will enable innovative applications in the future that are far beyond current printing technology capabilities,” added Lorenz. 

Even beyond solar cells, this system can also be useful for applications in optoelectronics, semiconductor manufacturing, and packaging technology.