IR laser-assisted micro/nano-imprinting

We report on the development of a new imprint method capable of transferring patterns down to nano-sized features from a silicon mold assisted by an infrared pulse laser during imprinting. We demonstrate that successful pattern transfer can be achieved easily on photoresist films of SU-8 5 from a silicon mold with a feature size of either 5 νm or 266 nm using a 1064 nm Nd:YAG laser. It is found that the IR pulse laser energy is absorbed predominantly by the silicon mold, and the pattern transfer is completed through heat transfer to the polymer. We also find that large area imprinting over 4 mm² and pattern transfer with concave features can be achieved by taking advantage of flexible Si mold fabrication. This method integrates strengths from hot embossing and laser-assisted direct imprinting. The rapid imprint speed and variety of three-dimensional structures available in silicon technology render this technique a strong candidate for many real-world applications.