A proof of principle for electrochemical screen printing (ESP) as a patterning process for thin metal stacks that can be employed, eg, in interdigitated back contact (IBC) or silicon heterojunction (SHJ) solar cells, is demonstrated. By using the ESP process, a 125 × 125-mm 2 interdigitated back contact grid was successfully patterned into a 100-nm physical vapor deposited (PVD) aluminum layer. Optimizations of the ESP process were performed to improve the patterning resolution. Rectangular trenches with a mean width of 36 ± 5 μm could be demonstrated on a 100-nm-thick aluminum layer. Up to now, ESP can be applied to PVD aluminum, copper, or stacks of both materials. Finally, metal stacks of aluminum and copper were structured, which allow a more homogeneous current distribution for the ESP process and additionally for the subsequent copper electroplating because of the second metal layer underneath the layer to be structured. The successful transfer from wafer substrate to polymer foils increases the application options of ESP technology enormously, where the topography of the surface to be structured affects the printing results.
KEYWORDSAl/Cu stack, electrochemical etching, flexible circuit board, interdigitated back contact (IBC) solar cell, plating, screen printing, silicon, water-based printing pasteThis is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.