Publications without theses

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Weigert, Florian; Thier, Daniel; Theska, René
Investigations on low-friction kinematic couplings based on compliant mechanism. - In: Proceedings of the 21st International Conference of the European Society for Precision Engineering and Nanotechnology, (2021), S. 517-518

Ortlepp, Ingo; Fern, Florian; Schienbein, Ralf; Supreeti, Shraddha; Füßl, Roland; Theska, René; Sinzinger, Stefan; Manske, Eberhard
Traceable 5D-nanofabrication with nano positioning and nano measuring machines. - In: Proceedings of the 21st International Conference of the European Society for Precision Engineering and Nanotechnology, (2021), S. 333-336

Today, besides the ongoing progress in the reduction of feature sizes, the measuring and fabrication of freeform surfaces with nanometre uncertainty, e.g. for aspheric lenses or structures with high aspect ratios, are a challenging task. Usually, dealing with such objects is limited by the local tilt angle between the object surface and the tool axis. There are different approaches to perform such measurements. In this paper, an extension of the Nano Measuring Machine NMM-1 with two rotational axes is described. With the proposed setup, it is possible to orientate the tool-axis perpendicular to the sample in every position, allowing larger angles to be measured / structured and minimising the uncertainty of the process e.g. due to the tilt dependency of the tool. Various machine designs are investigated and finally a solution with one rotary and one goniometer stage is integrated, preserving the existing machine infrastructure and allowing the addressability of a full hemisphere without limiting the measuring volume. As the tool centre point maintains its position during tool rotation, the Abbe principle is still fulfilled in every angular orientation. Emphasis was put on the metrological traceability of the whole system, including linear and rotary axes as well the tool itself. This was achieved by using a reference hemisphere, compensating the trajectory errors of the rotational axes. For the developed arrangement, the measurement uncertainty was investigated and several strategies for an in-situ-calibration of the additional axes are described. Finally, nanofabrication on large slopes is demonstrated.



Schienbein, Ralf; Theska, René; Fern, Florian; Füßl, Roland; Manske, Eberhard
On the development of five-axes nanopositioning machines for measurement and fabrication purposes based on Cartesian systems. - In: Proceedings of the 21st International Conference of the European Society for Precision Engineering and Nanotechnology, (2021), S. 213-216

Hübner, Maria; Miettinen, Mikael; Vainio, Valtteri; Cierpka, Christian; Theska, René; Viitala, Raine
Behaviour of porous aerostatic bearings with various restrictor permeabilities. - In: Proceedings of the 21st International Conference of the European Society for Precision Engineering and Nanotechnology, (2021), S. 115-118

Aerostatic bearings are externally pressurized gas lubricated bearings. Aerostatic bearings are used in high speed and precision motion applications due to low friction and high accuracy. They use a restrictor to limit the flow of the gas into the bearing gap. The presence of the restrictor increases the stability of the bearing against self-excited vibrations. This study focuses on porous graphite restrictors and the effect of permeability on the behaviour of the bearing. The bearings were studied both experimentally and with a simulation model. Flat bearing pads with 37 mm diameter and different restrictor bulk permeability were manufactured and tested. Experimental measurements were conducted on a test setup allowing loading of the bearing against a ground steel plate. The load was supplied with a series of weights. The air gap was measured with a linear length gauge, measuring the displacement of the air bearing. The pressure was controlled with a regulator and the flow rate into the bearing was measured. In order to build an accurate simulation model, the permeability of the used material was calculated from the measured short circuit flow through each 4.5 mm thick sample. The flow in the porous material and in the restrictive layer follows Darcy's law, the flow in the air gap is described by the Navier-Stokes-equation. The simulation model was validated with experimental results. Measurement and simulation results include the air gap height, load and flow rate at a supply pressure of 0.4 MPa. According to previous research and preliminary results the surface restrictor layer has increased the resistance of the bearing to self-excited airhammer vibration, leading to a higher load capacity.



Wittke, Martin; Wolf, Matthias; Darnieder, Maximilian; Weigert, Florian; Theska, René
Torque-compensating adjustment drive for mechanically sensitive devices. - In: Proceedings of the 21st International Conference of the European Society for Precision Engineering and Nanotechnology, (2021), S. 113-114

Layher, Michel; Bliedtner, Jens; Theska, René
Development of a laser beam deflection system for hybrid large scale additive manufacturing. - In: Proceedings of the 21st International Conference of the European Society for Precision Engineering and Nanotechnology, (2021), S. 75-78

Pabst, Markus; Darnieder, Maximilian; Theska, René; Fröhlich, Thomas
Adjustment concept for compensating stiffness and tilt sensitivity of a novel monolithic EMFC weighing cell. - In: SMSI 2021, (2021), S. 53-54

This paper describes the experimental investigation of a new adjustment concept for planar monolithic high precision electromagnetic force compensated weighing cells. The concept allows to adjust the stiffness and the tilt sensitivity of the compliant mechanisms to an optimum. A new prototype mechanism is set up and adjusted according to the developed mechanical model. For evaluation of the concept, the system was tested on a high precision tilt table and under high vacuum conditions.



https://doi.org/10.5162/SMSI2021/A3.1
Manske, Eberhard; Theska, René; Fröhlich, Thomas; Ortlepp, Ingo
Foreword to the special issue on "Tip- and laser-based 3D nanofabrication in extended macroscopic working areas". - In: Nanomanufacturing and metrology, ISSN 2520-8128, Bd. 4 (2021), 3, S. 131

https://doi.org/10.1007/s41871-021-00113-7
Supreeti, Shraddha; Schienbein, Ralf; Feßer, Patrick; Fern, Florian; Hoffmann, Martin; Sinzinger, Stefan
Development and implementation of a rotating nanoimprint lithography tool for orthogonal imprinting on edges of curved surfaces. - In: Nanomanufacturing and metrology, ISSN 2520-8128, Bd. 4 (2021), 3, S. 175-180

Uniform molding and demolding of structures on highly curved surfaces through conformal contact is a crucial yet often-overlooked aspect of nanoimprint lithography (NIL). This study describes the development of a NIL tool and its integration into a nanopositioning and nanomeasuring machine to achieve high-precision orthogonal molding and demolding for soft ultraviolet-assisted NIL (soft UV-NIL). The process was implemented primarily on the edges of highly curved plano-convex substrates to demonstrate structure uniformity on the edges. High-resolution nanostructures of sub-200-nm lateral dimension and microstructures in the range of tens of microns were imprinted. However, the nanostructures on the edges of the large, curved substrates were difficult to characterize precisely. Therefore, microstructures were used to measure the structure fidelity and were characterized using profilometry, white light interferometry, and confocal laser scanning microscopy. Regardless of the restricted imaging capabilities at high inclinations for high-resolution nanostructures, the scanning electron microscope (SEM) imaging of the structures on top of the lens substrate and at an inclination of 45˚ was performed. The micro and nanostructures were successfully imprinted on the edges of the plano-convex lens at angles of 45˚, 60˚,and 90˚ from the center of rotation of the rotating NIL tool. The method enables precise imprinting at high inclinations, thereby presenting a different approach to soft UV-NIL on curved surfaces.



https://doi.org/10.1007/s41871-021-00114-6
Ortlepp, Ingo; Fröhlich, Thomas; Füßl, Roland; Reger, Johann; Schäffel, Christoph; Sinzinger, Stefan; Strehle, Steffen; Theska, René; Zentner, Lena; Zöllner, Jens-Peter; Rangelow, Ivo W.; Reinhardt, Carsten; Hausotte, Tino; Cao, Xinrui; Dannberg, Oliver; Fern, Florian; Fischer, David; Gorges, Stephan; Hofmann, Martin; Kirchner, Johannes; Meister, Andreas; Sasiuk, Taras; Schienbein, Ralf; Supreeti, Shraddha; Mohr-Weidenfeller, Laura; Weise, Christoph; Reuter, Christoph; Stauffenberg, Jaqueline; Manske, Eberhard
Tip- and laser-based 3D nanofabrication in extended macroscopic working areas. - In: Nanomanufacturing and metrology, ISSN 2520-8128, Bd. 4 (2021), 3, S. 132-148

The field of optical lithography is subject to intense research and has gained enormous improvement. However, the effort necessary for creating structures at the size of 20 nm and below is considerable using conventional technologies. This effort and the resulting financial requirements can only be tackled by few global companies and thus a paradigm change for the semiconductor industry is conceivable: custom design and solutions for specific applications will dominate future development (Fritze in: Panning EM, Liddle JA (eds) Novel patterning technologies. International society for optics and photonics. SPIE, Bellingham, 2021. https://doi.org/10.1117/12.2593229). For this reason, new aspects arise for future lithography, which is why enormous effort has been directed to the development of alternative fabrication technologies. Yet, the technologies emerging from this process, which are promising for coping with the current resolution and accuracy challenges, are only demonstrated as a proof-of-concept on a lab scale of several square micrometers. Such scale is not adequate for the requirements of modern lithography; therefore, there is the need for new and alternative cross-scale solutions to further advance the possibilities of unconventional nanotechnologies. Similar challenges arise because of the technical progress in various other fields, realizing new and unique functionalities based on nanoscale effects, e.g., in nanophotonics, quantum computing, energy harvesting, and life sciences. Experimental platforms for basic research in the field of scale-spanning nanomeasuring and nanofabrication are necessary for these tasks, which are available at the Technische Universität Ilmenau in the form of nanopositioning and nanomeasuring (NPM) machines. With this equipment, the limits of technical structurability are explored for high-performance tip-based and laser-based processes for enabling real 3D nanofabrication with the highest precision in an adequate working range of several thousand cubic millimeters.



https://doi.org/10.1007/s41871-021-00110-w