Half Cell Cutting using Thermal Laser Separation

Increased Module Efficiency by Application of TLS Cell Cutting

Conventional cell cutting processes are based on a laser scribing method, with subsequent mechanical cleaving. Disadvantages of this method include the lowering of cell efficiency, the reduced mechanical stability of the cell, and the involved handling because of the combined lasing and subsequent cleaving procedure.

To overcome these drawbacks, 3D-Micromac uses the patented Thermal Laser Separation (TLS) for cutting of half-cells. Originally, TLS™ was employed in the back-end of the semiconductor industry for separating components made of semiconductor wafers, and could be successfully harnessed for use in cutting solar cells. After initially scribing a 200 µm long and 20 µm deep ablation groove to define the starting point on the edge of a wafer, the substrate is heated locally by a laser and subsequently cooled down by a mist of DI water. By skillfully superimposing both areas a stress field comprised of tensile and compressive stresses is generated in which a fissure can be introduced, independent of any possible grain boundaries or preferred breakage directions. The TLS™ method is suitable for most brittle semiconductor materials.

Compared to conventional separation technologies, TLS impresses with its clean, microcrack-free edges. No crystal damage occurs on the separation edge – damage which is otherwise common to date due to the displacement of re-solidified silicon in the ablation region. As opposed to laser cutting, no bulging and no formation of particles occur, because the substrate is merely heated and not vaporized. The mechanical stability of TLS™-processed solar cells is significantly greater than conventionally processed solar cells. The process leaves no residue. The few micro-liters of DI water required for cooling immediately evaporate.

TLS allows feed rates of up to 300 mm/s. With that TLS technology achieves up to triple the processing speed of conventional ablation and separation methods. Throughput averages at around 10,000 half-cells per hour. The process takes place “on the fly”.

microCELL™ TLS – On-the-Fly Cell Cutting System

3D-Micromac‘s microCELLTM TLS is a highly productive laser system for separation of standard silicon solar cells into half cells. The microCELLTM TLS meets cell manufacturers‘ demands by retaining the mechanical strength of the cut cells. The ablation free process guarantees an outstanding edge quality. Laser processing on-the-fly and an innovative handling concept enable maximum throughput and yield in the full-scale manufacturing of crystalline half cells.

microCELLTM TLS offers:

  • On-the-fly laser processing with unbeatable cost-benefit ratio
  • One-pass contactless dicing process
  • High throughput > 5,000 wph/> 10,000 half cells on single lane
  • Dicing speed up to 300 mm/sec
  • Low cost of ownership and CAPEX
  • Inline integration into existing production lines

Contact us now!

3D-Micromac AG

Frederick Bamberg
Product Line Manager Photovoltaics

Tel: +49 371 40043-432
E-Mail: bamberg@3d-micromac.com