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In this contribution, we present the results of a systematic material variation for the development of a resist material for high resolution positive tone electron beam lithography (EBL). Several acrylic copolymer materials with different compositions, that is varying mass fractions of the comonomers and different molecular weights, were synthesized and – as resist solutions – evaluated in terms of EBL performance at acceleration voltages of 30 kV and 100 kV. The resist material exhibiting the best combination of the desired properties, named mr-PosEBR, is two times more sensitive than PMMA 495k and performs comparably to the known high resolution resist ZEP520A at 30 kV. For example, a grating pattern with 29 nm wide lines with a period of 100 nm could be lithographically generated in films of mr-PosEBR with an area dose of 100 μC/cm2. In terms of resolution, single lines of only 35 nm width could be fabricated via metal liftoff. Furthermore, the dry etch stability of mr-PosEBR in a CF4/SF6 process is similar to the one of ZEP520A. Consequently, via dry etching nano patterns in mr-PosEBR could be smoothly transferred into the underlying Si substrate with high fidelity. Moreover, mr-PosEBR was evaluated as electron beam grayscale patterning and reflow resist. It was shown that the resist exhibits a good grayscale and reflow performance very similar to PMMA 120k and ZEP520A. Via these well controllable processes the generation of a wide variety of features and applications is possible.

The high throughput and large area nanostructuring of flexible substrates by continuous roller processes has great potential for future custom applications like wire grid polarizers, antireflection films, or super-hydrophobic surfaces. For each application different material characteristics have to be considered, e.g. refractive index, hydrophobicity, or dry etch stability. Herein, we show experimental results of nanoimprint lithography resist developments focused on inkjetable and photo-curable resists suitable for high throughput production, especially roll-to-roll NIL. The inkjet deposition of the novel materials is demonstrated by the use of different state-of-the-art inkjet printheads at room temperature. A plate-to-plate process on silicon substrates was successfully implemented on a NPS300 nano patterning stepper with previously inkjet dispensed NIL resist. Furthermore, we demonstrate a throughput of 30 m min-1 in a roller NIL process on PET. Dry etching of unstructured thin films on Si wafers was performed, and it was demonstrated that the etch stability in Si is tunable to a value of 3.5:1 by a concise selection of the resist components. The surface roughness of the etched films was measured to be < 2 nm, after etching of around 100 nm of the resist films what is an essential factor for a low line edge roughness. All resists reported herein can be deposited via inkjet dispensing at room temperature, are suitable for continuous high throughput imprinting on flexible substrates, and are applicable in step-wise NIL processes with good etch resistance in dry etch processes.

One of the key elements for the successful integration of nanoimprint lithography into industrial production processes is the availability of high-performance resist materials. In this contribution we present a novel low-viscosity and fast curing UV-NIL polymer, which is applied by spin-coating and designed for wafer-scale imprinting. Systematic investigations of photocurable components and photoinitiators led to the formulation of the polymer system mr-UVCur06. Film thicknesses in the range of 50 - 500 nm with excellent quality and uniformity could be obtained by spin-coating. Its suitability for UV-NIL processes was evaluated by means of imprinting tests and plasma etching investigations. This included investigations on imprinting with hard moulds, UV curing doses, resolution, etch rates using various plasma gases and pattern transfer. The beneficial flow behaviour of mr-UVCur06 led to short UV-NIL cycle times. Patterns of several orders of magnitude with feature sizes in the range of 30 nm to several tens of micrometers could be imprinted simultaneously. An example of a pattern transfer into Si was shown, where mr-UVCur06 was used as an polymer etch mask.