Fabrication of 3D-photonic crystals via UV-nanoimprint lithography

Optical lithography will reach its limits due to the diffraction effects encountered and the necessity for using complex resolution enhancement techniques like optical proximity correction, phase shift masks, and off-axis illumination [L. W. Liebmann et al., in Advanced Semiconductor Lithography (2001), Vol. 45]. The restrictions on wavelength, in combination with high process and equipment costs, make low-cost, simple imprinting techniques competitive with next-generation lithography methods. There are several nanoimprint lithography (NIL) techniques which can be categorized depending on the process parameters and the imprinting method—either step and repeat or full wafer single-step imprinting. A variety of potential applications has been demonstrated using NIL (e.g., surface acoustic wave devices, vias and contact layers with dual damascene imprinting process, Bragg structures, patterned media) [M. D. Stewart et al., Proc. SPIE 5751, 210 (2005); P. Dorsey et al., in Discrete Track Recording (DTR) Media Fabricated using Nanoimprint Lithography, NNT 1–3 December (2004)]. In this work UV-NIL has been selected for the fabrication process of 3D-photonic crystals.