Fabrication of low-cost submicron patterned polymeric replica mold with high elastic modulus over a large area

Abstract

Low cost submicron patterning technique to fabricate a large area polymeric replica mold using an ultraviolet nanoimprint lithography (UV-NIL) technique is reported. A photo-curable polyurethane-acrylate (PUA) precursor was densified via UV light in order to form a solid polymeric replica mold and to maximise its stability, yet stable mechanical properties with different UV-exposure times were studied using a nanoindentation method as a function of the penetration depth during the loading–unloading cycles. The PUA replica mold demonstrated very high mechanical properties of hardness (0.15 GPa) and elastic modulus (2.7 GPa) due to the increased cross-linking density of the PUA precursor at an optimized UV-exposure time of 600 s. The PUA replica mold demonstrated potential for the fabrication of multi-scale line-and-space patterns with sizes of 350 nm or less with good uniformity and reproducibility over large areas. The replication of the polymeric mold with high durability and excellent mechanical properties can be economically valuable to physical contact nanolithography processes for the high throughput fabrication of micro- and nanodevices.