Investigating the pattern transfer fidelity of Norland Optical Adhesive 81 for nanogrooves by microtransfer molding

Abstract

We demonstrated the microtransfer molding of Norland Optical Adhesive 81 (NOA81) thin films. NOA81 nanogrooves and flat thin films were transferred from a flexible polydimethylsiloxane (PDMS) working mold. In the case of nanogrooves, the mold's feature area of 15 × 15 mm2 contains a variety of pattern dimensions in a set of smaller nanogroove fields of a few mm2 each. We demonstrated that at least six microtransfers can be performed from the same PDMS working mold. Within the restriction of our atomic force microscopy measurement technique, nanogroove height varies with 82 ± 11 nm depending on the pattern dimensions of the measured fields. Respective micrographs of two of these fields, i.e., one field designated with narrower grooves (D1000L780, case 1) and the other designated with wider grooves (D1000L230, case 2) but with the same periodicity values, demonstrate faithful transfer of the patterns. The designated pattern dimensions refer to the periodicity (D) and the ridge width (L) in the original design process of the master mold (dimensional units are nm). In addition, neither NOA81 itself (flat films) nor NOA81 nanogroove thin films with a thickness of 1.6 μm deteriorate the imaging quality in optical cell microscopy.