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

Abstract

In recent years the standard lithography reached its limits due to the diffraction effects encountered and the necessary complexity of compatible masks and projection optics. 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 & repeat or full wafer imprinting. A variety of potential applications has been demonstrated using NIL (e.g. SAW devices, vias and contact layers with dual damascene imprinting process, Bragg structures, patterned media) [1,2]. In this work UV-NIL has been selected for the fabrication process of 3D-photonic crystals. Results with up to three layers will be demonstrated.

Colloidal Lithography for Photovoltaics: An Attractive Route for Light Management

“…Nevertheless, these techniques do not entirely mitigate the previously mentioned issues of photolithography, such as the cost, low throughput, and the requirement for highly sophisticated equipment. Hence, such disadvantages prompted research for unconventional soft-lithography fabrication techniques [ 39 ] as: nanoimprint lithography (NIL) [ 42 , 43 ], hot embossing [ 44 ], thermal injection molding [ 45 ], light-initiated polymerization (with ultraviolet, UV-NIL, and step-and-flash NIL [ 43 , 46 ]), solvent-based processing [ 47 ], and colloidal lithography (CL) [ 48 ]. These cost-effective soft techniques have brought focus to the patterning world, as they can be used in nonpolar surfaces—increasing the range of allowed materials, enable large scale patterning, and most importantly, employ industrially attractive fabrication methods due to their ease of use and low manufacturing cost [ 49 ].…”