Articles you may be interested inContinuous and scalable fabrication of flexible metamaterial films via roll-to-roll nanoimprint process for broadband plasmonic infrared filtersAs an emerging technology for the manufacture of micro-and nano-scale patterns, continuous imprinting; otherwise known as roll-to-roll or roller imprinting, is attracting interest from researchers around the world because of its inherent advantages of low cost, high throughput, large area patterning. This technology is an evolutionary advance on the more traditional nanoimprint lithography developed in the 1990s, which is considered a batch mode, or dis-continuous patterning approach. In recent years, a number of commercial applications have been discovered which require low cost, large area patterning, particularly displays, optical coatings and films, and biological applications such as anti-fouling surfaces and micro-fluidic devices. This review covers a variety of continuous imprinting approaches, highlights challenges, and surveys progress towards high speed production of micro-and nanoscale features for these applications and others using this platform technology.

We present a new approach for fabricating isolated, sealed, high-density nanofluidic channel arrays using combinatorial-mould nanoimprint lithography. This method provides a directed stamping technique for fabricating micro- to nanoscale channel arrays from the simple combination of two grating moulds of the proper geometry. In this method, a thin polymer film is cast on a silicon grating mould and subsequently embossed with a second grating mould. The film, after it is patterned on both sides, is then stamped onto a substrate and etched with oxygen plasma to remove the suspended residue layer and isolate the nanochannels. We have successfully fabricated arrays of high-density nanochannels on silicon and indium tin oxide glass (ITO glass) with well-controlled dimensions (i.e. 250 nm square, in cross-section). Placing a nanochannel array in contact with an aqueous fluorescein solution fills the channels by capillary action, and the integrity of the seal formed by the nanochannel enclosures was verified by observing a significant contrast in the photobleaching rate under fluorescence microscopy.

UV roll-to-roll nanoimprinting at high resolution is still a relatively unexplored field of study with far-reaching application potential. One enabling technology that is particularly worthy of attention is mass production of high resolution resin moulds via UV roll-to-roll nanoimprinting at such high throughput and low cost that they can be used only once and disposed of or recycled economically. Low cost, high resolution resin moulds can greatly improve the production cost profile for a number of applications in biomedicine, nanofluidics, data storage and electronics with relatively low unit values but which require one or more nanoscale lithography steps. In this report, UV roll-to-roll nanoimprinting was employed to fabricate high fidelity resin moulds with nanoscale as well as mixed micro- and nanoscale features down to 50 nm feature diameter, at up to 120 cm(2) area and at 10 m min(-1) throughput. UV roll-to-roll nanoimprinted resin moulds were subsequently segmented out, employed in a batch mode thermal nanoimprinting process, and characterized to study performance and demonstrate viability. The results show that high resolution mixed nanostructures can be faithfully replicated in PMMA on silicon substrates with minimal volumetric shrinkage. Process details and challenges specific to roll-to-roll fabrication of resin moulds are discussed at length, particularly with respect to the curvature uniformity of the imprint roller.

A new method for imprinting residual‐layer free polymer micro‐ and nano structures, particularly 3‐D structures with overhang, is demonstrated. This simple and versatile method induces self‐removal of the residual layer by controlled failure of the patterned film along the edges of the imprinted features. Pristine overhang structures down to ∼500 nm diameter are realized without exposure to plasma or chemical etchants.