Kentaro Tsunozaki

Fabrication of flexible UV nanoimprint mold with fluorinated polymer-coated PET film

UV curing nanoimprint lithography is one of the most promising techniques for the fabrication of micro- to nano-sized patterns on various substrates with high throughput and a low production cost. The UV nanoimprint process requires a transparent template with micro- to nano-sized surface protrusions, having a low surface energy and good flexibility. Therefore, the development of low-cost, transparent, and flexible templates is essential. In this study, a flexible polyethylene terephthalate (PET) film coated with a fluorinated polymer material was used as an imprinting mold. Micro- and nano-sized surface protrusion patterns were formed on the fluorinated polymer layer by the hot embossing process from a Si master template. Then, the replicated pattern of the fluorinated polymer, coated on the flexible PET film, was used as a template for the UV nanoimprint process without any anti-stiction coating process. In this way, the micro- to nano-sized patterns of the original master Si template were replicated on various substrates, including a flat Si substrate and curved acryl substrate, with high fidelity using UV nanoimprint lithography.

Evaluation of UV roller imprinting using replicated fluorinated film molds

In this study, a fluorinated UV-curable resin was replicated by UV imprinting and used as a film mold. The film mold was fabricated by anti-sticking process (ACP). A remarkable advantage of the application for easy mold fabrication is expected, because it uses only UV imprinting. We evaluated two types of the pattern replications, directions between the stage movement and line and space (L&S) patterns in perpendicular as well as in parallel. The results of replication tests show obvious difference between UV roller imprinting and UV roller press imprinting. In addition, Vickers hardness is measured to evaluate the thermal property of UV roller imprinting. The results indicate that temperature is effective not only to improve pattern replication, but also to accelerate UV curing.