6 inch full field wafer size nanoimprint lithography for photonic crystals patterning

The HB-LED market grew rapidly in the last years and will see grater than 50% growth this year. The current applications are dominated by portable device backlighting, e.g. cell phones, PDAs, GPS, laptop etc. In order to open the general lighting market doors the luminous efficiency needs to be improved significantly. Photonic crystal (PhC) structures in LEDs have been demonstrated to enhance light extraction efficiency on the wafer level by researchers. However, there is still a great challenge to fabricate PhC structures on LED wafers cost-effectively. Nanoimprint lithography (NIL) is one promising technology for manufacturing of electronic devices of low nm scale. However, the current NIL techniques with rigid stamps rely strongly on the substrate flatness and the production atmosphere. UV-NIL with flexible stamps, e.g. PDMS stamps, allows the large-area imprint in a single step and is less-sensitive to the production atmosphere. Unfortunately, the resolution is normally limited due to stamp distortion caused by imprint pressure. The NIL technique developed by Philips Research and SUSS MicroTec, substrate conformal imprint lithography (SCIL), bridges the gap between UV-NIL with rigid stamp for best resolution and soft stamp for large-area patterning.