A Simple Imprint Method for Multi‐Tiered Polymer Nanopatterning on Large Flexible Substrates Employing a Flexible Mold and Hemispherical PDMS Elastomer

This work reports a facile method to fabricate multi‐tiered polymer nanopatterns on SU‐8 by the combination of imprint‐ and photo‐lithography. First, SU‐8 is imprint patterned using a polymeric flexible mold with an anti‐adhesion coating that is deposited on a transparent and flexible substrate, at room temperature under low pressure. Next, the resulting SU‐8 nanopatterns are exposed to UV light through a chromium mask by a photolithographic process. Removal of the unexposed SU‐8 leaves behind multi‐tiered structures. The use of a hemispherical poly(dimethylsiloxane) pad facilitates the evacuation of trapped air during the imprinting process. Line/space patterns of 500 nm with the smallest line width of 200 nm were homogeneously imprint‐patterned on SU‐8 on a large flexible substrate, and three‐tiered structures, ranging in thickness from 300 nm to 2 µm, were successfully formed.