Control over pattern fidelity and surface wettability of imprinted templates for flexible color filter manufacturing

This paper presents a universal approach for fabricating flexible color filter template with the high-fidelity patterns using R2R NIL in combination with microcontact printing which provides a solution for selective surface hydrophobization. The pattern transfer fidelity being critical in color filter manufacturing, as a function of imprinting parameters such as a roller pressure and web speed, is thoroughly investigated. We also discuss influence of various imprint resins, the thermal exposure and oxygen RIE on vertical dimensions measured using white-light scanning interferometer. Through the evaluation of all measurements of pattern height, the optimal R2R NIL process parameters are determined. By increasing the roll pressure and reducing the web speed, the pattern fidelity of a polymeric template is improved, reaching 93% of the original pattern height. The patterned surface is modified to achieve hydrophilicity and then locally printed with hydrophobic SAM. Channels become hydrophobic with WCA of 105 degrees on the top and the uncoated regions at the bottom remain hydrophilic with WCA of 21 degrees, exhibiting selective wetting. A high wettability contrast facilitates uniform ink filling into the channels and prevents ink diffusion during inkjet printing. (C) 2011 Elsevier B.V. All rights reserved.