DEK Solar Introduces ECN Delegates to Latest Advances in Print-on-Print Technology

DEK Solar Senior Process Development Specialist, Tom Falcon, recently presented the company’s latest advances in print-on-print (PoP) technology to assembled delegates at a metallization workshop organised by the Energy research Centre of the Netherlands (ECN). During the workshop, Falcon outlined the findings of a major research project conducted by the company along with associated opportunities for solar cell metallization.

DEK’s Senior Process Development Specialist presented the PoP paper to around 200 industry professionals, customers and academics. The two-day event in Germany was designed to showcase research and development from universities, institutes and industry in the field of metallization for crystalline silicon solar cells. Commenting on the significance of his presentation, Falcon explains: "Print-on-Print itself is not a new idea; but the implementation of this technique in a high volume manufacturing environment requires much more than an accurate printing machine. It requires an optimised process with each print operation finely tuned for maximum performance, both individually and in combination. What’s more, this must be repeatable over many thousands of wafers. Our new research outlines the development of a successful PoP process to show how we can deliver a measurable and consistent improvement over a single print for dramatically improved productivity.”

The DEK Solar paper describes the development of a PoP process for high aspect ratio frontside conductors, with in-depth results spanning the testing of various screen types, aperture widths, emulsion thickness, paste types and process parameters to empirically determine optimisation. Conclusions reached include the fact that paste choice is critical to maximise performance and that quality screens are essential for alignment. Finer meshes and moderate emulsion are identified as delivering optimal prints while screen life is proven to stand at around 7.5K wafers. Ultimately, DEK Solar evidenced that around a 40 percent increase in conductor aspect ratio is possible and sustainable in high volumes over a single print.

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