Multilength Scale Patterning of Functional Layers by Roll-to-Roll Ultraviolet-Light-Assisted Nanoimprint Lithography

Abstract

Top-down fabrication of nanostructures with high throughput is still a challenge. We demonstrate the fast (>10 m/min) and continuous fabrication of multilength scale structures by roll-to-roll UV-nanoimprint lithography on a 250 mm wide web. The large-area nanopatterning is enabled by a multicomponent UV-curable resist system (JRcure) with viscous, mechanical, and surface properties that are tunable over a wide range to either allow for usage as polymer stamp material or as imprint resist. The adjustable elasticity and surface chemistry of the resist system enable multistep self-replication of structured resist layers. Decisive for defect-free UV-nanoimprinting in roll-to-roll is the minimization of the surface energies of stamp and resist, and the stepwise reduction of the stiffness from one layer to the next is essential for optimizing the reproduction fidelity especially for nanoscale features. Accordingly, we demonstrate the continuous replication of 3D nanostructures and the high-throughput fabrication of multilength scale resist structures resulting in flexible polyethylenetherephtalate film rolls with superhydrophobic properties. Moreover, a water-soluble UV-imprint resist (JRlift) is introduced that enables residue-free nanoimprinting in roll-to-roll. Thereby we could demonstrate high-throughput fabrication of metallic patterns with only 200 nm line width.

High‐Aspect‐Ratio Nanostructured Surfaces as Biological Metamaterials

“…Track-etched membrane/nanopore templates Nanoelectrodes, [145] spiky microstraws, [93] nanopillar arrays, [146] nanostraws [89,90] ≈0.1 [88] ≤100 [88] Templates are highly affordable Large patternable areas No cleanroom required Limited or no control over location of individual pores Nanoimprint lithography b) Nanowires, [147] nanopillars, [146,148] nanostructures [149] ≤0.04 [151] to 25 ≤150 [151] (very large area roll-to-roll patterning reported) [149] Parallel/quick patterning process Good resolution Excellent for reproducing existing designs Very large area patterning possible Requires expensive master stamp/shim Care required to optimize resist and surface treatments to ensure good demolding Nanosphere/colloidal lithography Nanowires, [27,152,153] nanoelectrodes, [134] nanopillars [154] ≈0.1-2 [155,156] 1 × 10 3 (areas of up to 1 m 2 reported) [156] Affordable method Achievable with relatively simple equipment Very large area patterning possible…”

“…[66] The process can be readily upscaled using roll-to-roll manufacturing techniques, allowing replication on unprecedented (kilometer) scale. [149] Hot embossing is conceptually similar to nanoimprint lithography and involves pressing a polymer film into a prepatterned design (referred to as a die). This process transfers the pattern into the film.…”

Superhydrophobic Properties of Nanotextured Polypropylene Foils Fabricated by Roll-to-Roll Extrusion Coating

“…It was originally demonstrated by Ahn et al, 16,17 and more recently by Leitgeb et al with even faster roller speed in excess of 10 m/min on a 25 cm wide web. 18 This R2R method is feasible for nanostructuring but is limited with regard to surface chemistry, as the relief must be formed in a UV- width of 6 in (∼150 mm). A R2R method for production of large area superhydrophobic surfaces should preferably have much higher productivity and allow structuring of common inexpensive and intrinsically hydrophobic polymers such as polyethylene, 21 cyclic olefin copolymer, 22 or polypropylene (PP) 23 to gain practical relevance.…”

Continuous manufacturing of reentrant structures via roll‐to‐roll process

“…The objective of this article was to fabricate reentrant structures on a polymer sheet using the R2R hot embossing (R2R‐HE) process. This process differs from the R2R UV‐assisted nanoimprint lithography and R2R extrusion coating processes, which have been effectively used for creating surface structures but have not been used to create reentrant structures.…”