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We present a versatile and scalable method for the preparation of microfluidic channels with incorporated nano patterns. Since our approach is highly industrial driven, all used methods and materials are available in common micro-fabrication environment and are available in large quantities, respectively. In comparison to other fabrication methods capable of realizing multi-level patterns, we combine nanoimprint lithography with standard photolithography, and thereby overcome the problems of limited pattern dimensions as well as fabrication time, pathing the way for a new class of microfluidic devices.

The continuous miniaturization of components and devices along with the increasing need of sustainability in production requires materials which can fulfill the manifold requests concerning their functionality. From an industrial point of view emphasis is on cost reduction either for the materials, the processes, or for both, along with a facilitation of processing and a general reduction of resource consumption in manufacturing. Multifunctional nanoscale materials have been widely investigated due to their tunable material properties and their ability to fulfill the increasingly growing demands in miniaturization, ease of processes, low-cost manufacturing, scalability, reliability, and finally sustainability. A material class which fulfills these requirements and is suited for integrated or waferscale optics are inorganic–organic hybrid polymers such as ORMOCER®s [ORMOCER®is registered by the Fraunhofer Gesellschaft für Angewandte Forschung e.V. and commercialized by microresist technology GmbH under license since 2003]. The combination of chemically designed multifunctional low-cost materials with tunable optical properties is very attractive for (integrated) optical and waferscale applications via a variety of different nano- and microstructuring techniques to fabricate micro- and nano-optical components, typically within less than a handful of process steps. The influence of photoinitiator and cross-linking conditions onto the optical properties of an acrylate-based inorganic–organic hybrid polymer will be discussed, and its suitability for being applied in waferscale optics is demonstrated and discussed for miniaturized multi- and single channel imaging optics.

Herein, we present the results of a systematic material development study we carried out in order to obtain a new positive tone resist for high resolution electron-beam lithography. Several acrylic copolymer materials with different mass fractions of the comonomers, different molecular weights and similar molecular weight distributions were synthesized and - as resist solutions - evaluated in terms of electron-beam lithography performance. On the one hand, within the ranges investigated, it was shown that the lithographic sensitivity is significantly influenced by the composition rather than by the molecular weight or molecular weight distribution. On the other hand, the etch resistance of the materials remains unaffected by changes of these parameters. The resist material exhibiting the best combination of the desired properties, mr-PosEBR, is 2 times more sensitive than PMMA (495kDa) and performs comparably to the known high resolution resist ZEP520A. For example, a grating pattern with 29nm wide lines with a period of 100nm could be generated in films of mr-PosEBR with an area dose of 100µC/cm2. In terms of resolution, single lines of only 35nm width could be fabricated via metal lift-off using 100kV EBL. Furthermore, the dry etch stability of mr-PosEBR in a reactive-ion etching (RIE) process (etch gases: CF4/SF6) is similar to the one of ZEP520A (etch rates, mr-PosEBR: 190nm/min, ZEP520A: 150nm/min, silicon: 440nm/min). Moreover, high resolution nanopatterns in mr-PosEBR could be smoothly transferred into the underlying Si substrate by a RIE process. Display Omitted A new resist material for high resolution electron-beam lithography is presented.The resist was developed by the systematic variation of its copolymeric composition.The new material provides high sensitivity, high resolution and high etch stability.

We present a new epoxy-based negative-tone dry film photoresist (DFR) for fabricating multilayer microfluidic devices using a lamination process combined with a standard photolithography technology. As proof-of-concept, a complex 3D-hydrodynamic focusing device was produced via a six-layer lamination process of 33 µm-thick DFR layers. The bonding strength of the new DFR was tested on silicon, glass, and titanium substrates, respectively. A maximum bonding strength of 37 MPa was obtained for the dry film photoresist laminated on glass. No leakage was found, and burst tests proved excellent robustness and sealing reliability of the microchannels.

This work presents a new type of high-resolution dry-film resist laminates for the fabrication of extremely thick epoxy based polymer structures. Via a lamination process a resist thickness of up to d=360@mm can be applied by one single process step. Afterwards, the dry-film resist is patterned by standard UV-lithography. An epoxy based resist mixture which contains epoxy resins, reactive diluents, additives, and a photo acid generator is deposited onto a PET supporting film by doctor blading for fabrication of the resist film. The films can be cut defect-free into favoured sheet sizes. Currently, dry-film resists with a layer thickness of up to 400@mm can be produced reproducible. With the tested d=360@mm thick dry-film resist an aspect ratio of 15:1 (height:width) has been achieved. By lamination and UV-patterning of two layers resist a master for 700@mm thick electroplated Nickel structures was fabricated. Thereby, steep side walls with an angle deviation of @a

There are two basic types of nanoimprint lithography: hot embossing using thermoplastic or thermosetting polymers and UV-based nanoimprint lithography (UV-NIL) using UV-curable polymer systems. Since the interest in UV-NIL has been constantly increasing within the last years, the need of suitable low-viscosity resists has increased, too. The availability of such materials is one key element of the UV-NIL technology. In this contribution a novel, spin-coatable polymer system for UV-NIL is presented. Suitable polymer components were evaluated using photoDSC analysis. Their ratio was adjusted in such a way that the overall dynamic viscosity of the mixture remained low which was beneficial for the flow behaviour. Film thicknesses in the range of 150-500nm could be obtained by spin-coating. The new polymer system was characterised in UV-NIL processes and in plasma etching investigations. Imprinted micrometer as well as nanometer scale patterns with feature sizes in the range of 30nm to several microns are shown.

LIGA is the basic idea of promising developments for the manufacturing of microelectromechanical system parts containing high aspect ratio microstructures. Aim of the work is a brief discussion of the starting-points for inline process inspection within a direct LIGA technology using deep X-ray lithography for the production of micromechanical gear wheels with critical dimensions of ∼35 μm width at ∼1 mm height as well as to show methodic and technical measuring possibilities. Firstly, results of the determination of residual solvent content distribution within ultra-thick SU-8 films are shown obtained from refracted near field optical measurements. Furthermore, the capability of X-ray computer tomographic imaging is discussed and measurements for the determination of the three-dimensional shape of high aspect ratio microstructures are practically demonstrated with microscopic and interferometric optical methods. Finally, first results demonstrate the potential of the optical coherence tomography for several further important measurement tasks, among others, e.g. for the imaging of the distribution of mechanical stress at the resist–substrate interface. The results show that much information which is essential in the LIGA process can be achieved with recently available measurement methods. However, further development of non-destructive measurement techniques would be desirable for an effective inline process control of mass production of micromechanical parts.

The use of working stamps for nanoimprint lithography is highly interesting for a number of reasons like an increased lifetime and often a better manufacturability of the master stamp. We present results on the use of Ormostamp as a material for working stamps in UV-NIL. Imprinting properties and anti-sticking treatments have been investigated. So far a minimum feature size of 50nm can be achieved.

Transparent stamps are an integral and crucial part of the UV-imprinting. Time consuming fabrication of quartz stamps increases the price of the technology. In the presented work a thermally stable transparent imprint stamp made of a novel hybrid polymer system is demonstrated. As a low-cost and highly efficient alternative the hybrid polymer stamp contributes to the acceptance and application of the nanoimprint technology. By using the UV-patternable inorganic-organic hybrid polymer quartz stamps might become superfluous in the UV-imprint process entirely, because transparent working stamps can be manufactured also with use of opaque silicon master stamps.

Graphical abstractDisplay Omitted R2R-NIL is presented with high throughput roller speeds of 30mmin-1 and good pattern fidelity.The viscosity of the novel materials is below 20mPas, enabling inkjet dispensing at room temperature.Throughput variation from 1mmin-1 to 20mmin-1 decreased double bond conversion less than 5%. We report two newly developed photo-curable resists specifically engineered for inkjet dispensing facilitating nanoimprint lithography (NIL) in a high-throughput environment. The viscosity of the novel NIL resists was adjusted especially to enable inkjet dispensing at room temperature. The novel resists can be applied either in NIL batch processes or in high throughput processes like roll-to-roll NIL (R2R-NIL). Batch-wise imprints were performed on various substrates as Si or plastics demonstrating the distinctive application versatility of the novel materials. The very fast curing speed of these materials is discussed in detail with the aid of FT-IR and photo-DSC measurements. The experiments demonstrate a high degree of double bond conversion of about 80% after curing and a fast curing in a few seconds even at a low radiation intensity of 0.2mWcm-2. The novel materials show excellent adhesion on different substrates and high optical transparency. The high throughput capability of the novel materials is demonstrated by R2R-NIL processes performed at a web speed of up to 30mmin-1.

We report on our development strategy of photo-curable resists for nanoimprint lithography (NIL) based on modularity. Starting with a basic formulation, we address two topics: the integration of fluorinated additives and the enhancement of the dry etching stability. We prove both concepts by the introduction of two different resists derived from the same basic formulation. The viscosity of the novel resist materials was optimized for inkjet dispensing at room temperature (RT). The novel resist materials can be applied either in NIL batch processes or in high-throughput roller processes. Batch-wise imprints were performed on various substrates such as Si or plastics, demonstrating the distinctive application versatility of the novel materials. Dry etching of spincoated thin films on Si wafers was performed, demonstrating an etch stability versus Si of 3.5:1 by using the resist formulation with improved etching stability. Roll-to-roll NIL at high throughput on large areas was performed with web speeds of up to 30 mmin−1 with different stamp materials. We conclude that all resists reported herein can be deposited via inkjet dispensing at RT, 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.

Advanced mask aligner lithography (AMALITH) is a holistic approach to improve shadow printing (contact and proximity lithography) in mask aligners. AMALITH is based on two tools, the MO Exposure Optics®, a new illumination system allow shaping the angular spectrum of the illumination light, and LAB, a software tool for full 3D simulation of the shadow printing process. MO Exposure Optics® is provided by SUSS MicroTec AG ( http://www.suss.com ), as an upgrade for all current and older mask aligner models. MO Exposure Optics® decouples the illumination from lamp misplacement (self-calibrated light source), improves the light uniformity, provides telecentric illumination and enables customized illumination in mask aligners. LAB is a software tool provided by GenISys GmbH ( http://www.genisys-gmbh.com ), and allows simulating the complete chain from illumination, mask pattern, photoresist and resist processing. The combination of both tools allows optimizing mask aligner lithography beyond today's limits.

Graphical abstractDisplay Omitted Highlights? We present a new thermal NIL resist for high-aspect-ratio patterns via a bilayer approach. ? The resist properties are tailored by free radical polymerization of specific comonomers. ? The resist shows excellent flowability and demoulding characteristics. ? A high oxygen RIE resistance demonstrates the suitability of the resist as a masking layer. We report a newly developed thermal nanoimprint (T-NIL) resist specifically engineered for the implementation in a bilayer system rendering the fabrication of high-aspect-ratio patterns. The synthesis of the T-NIL resist was accomplished by applying a free radical copolymerization of adequate comonomers. Due to the modular architecture of the terpolymer, the rather different material properties are directly adjusted by varying the amount of the comonomers and also by tuning the polymerization conditions like temperature and the amount of initiator. Following this synthetic strategy, the Si content for a sufficient oxygen plasma resistance as well as an excellent flowability behavior for a significant reduction of the overall processing cycle time could be easily achieved. Moreover, the already good mould release properties of the pure T-NIL resist can be further improved by the addition of a small amount of a fluorinated additive leading to a very low defect rate of the imprinted structures.

We present a new organic photosensitive material for volume holographic recording. Advanced material composition and sample preparation eliminates the need for a protective layer and allows layer fabrication with variable thickness and a free surface. Optimized chemical formulation results in a high energetic sensitivity, high angular selectivity and high inducible refractive index contrast. We investigate the photoresponse and nonsinusoidal refractive index profiles. We demonstrate highly resolved optical structuring with up to 8000 lines per mm. Imaging of the holographic phase gratings is accomplished by optical microscopy.

Microlens arrays fabricated by a direct ink-jet printing of UV-curable hybrid polymer are reported. A periodic pattern of polymer drops was ink-jet printed on the surface-treated glass substrate and cured in the UV-light. Using this simple technique, we demonstrated periodic arrays of almost semi-spherical microlenses of 50 μm diameter size and a focal distance of 48μm. The optical characteristics of solitary μ-lenses and arrays comprising up to 64x64 microlenses are measured both in the near- and far-field zones. Large numerical aperture and short focal distance make the ink-jet printing of microlenses very attractive for applications in optical interconnects, large 2D VCSEL arrays and pixelated imagine sensors utilizing CCD or SPAD arrays, offering thus an efficient, simple and a cheap alternative to the conventionally used photolithography technique.