Modifications to a high-precision direct laser writing setup to improve its laser microfabrication. - In: Laser-Based Micro- and Nanoprocessing XVI, (2022), 119890U, S. 119890U-1-119890U-7
Two-photon-absorption (2PA) techniques enables the possibility to create extremely fine structures in photosensitive materials. For direct laser writing as micro- or nanofabrication a laser system can be combined with highly precise positioning systems. These are mostly limited by a few hundreds micrometer positioning range with applications based on piezoelectric stages or even just relatively few tens micrometer positioning range with applications based on galvanometer scanners. Although these techniques are precise, but stitching methods are required for larger fabrication areas. Therefore, a setup consisting of a femtosecond laser for 2PA and a nanopositioning and nanomeasuring machine (NMM-1) was developed for high precision laser writing on lager surfaces. Further developments of the system should enable a significant improvement in high-precision and stitching free direct laser writing. In order to combine the the femtosecond laser and the NMM-1 into a functional unit, to write complex structures with highest accuracy and homogeneity, further improvements like a beam expansion for a better use of the numerical aperture of the objective and a new femtosecond laser with a integrated power measurement are realized. This showed improvements in line width for nano strucuring. Advantages and disadvantages as well as further developments of the NMM-1 system will be discussed related to current developments in the laser beam and nanopositioning system optimization.
https://doi.org/10.1117/12.2609417
Nanoscale surface morphology modulation of graphene - i-SiC heterostructures. - In: Materials today, ISSN 2214-7853, Bd. 53 (2022), 2, S. 289-292
A multitude gratings design consists of gratings with different pitches ranging from the micrometre down to sub 40 nm scale combined with sub 10 nm step heights modulating the surface morphology for length scale measurements is proposed. The surface morphology modulation was performed using electron beam lithography incorporating a standard semiconductor processing technology. The critical dimension, edge roughness, step heights and line morphology in dependence on the grating pitch is studied.
https://doi.org/10.1016/j.matpr.2021.06.427
Messunsicherheitsbetrachtung für die Kalibrierung von keramischen Wärmestromsensoren. - In: Messunsicherheit praxisgerecht bestimmen - Prüfprozesse in der industriellen Praxis 2021, (2021), S. 23-34
Der Beitrag zeigt die Bedeutung neuer thermischer Messverfahren für den Fahrzeugentwicklungsprozess im Bereich des Thermomanagements von Elektrofahrzeugen. Die Messung der Wärmestromdichte mit geeigneten Sensoren kann einen wichtigen Beitrag in der zukünftigen thermischen Abstimmung liefern. Hierfür werden neue keramische Wärmestromsensoren entwickelt, deren Grundprinzip erläutert wird. Für diese Wärmestromsensoren wird zudem eine geeignete Kalibriereinrichtung konstruiert. Das Funktionsprinzip dieser Kalibriereinrichtung sowie die messtechnischen Herausforderungen werden ebenfalls betrachtet. Abschließend werden sowohl wichtige Einflussfaktoren als auch grundlegende Messunsicherheitsbeiträge für den Wärmestromsensor und die Kalibriereinrichtung vorgestellt.
https://doi.org/10.51202/9783181023907-23
Frequenzkamm-gekoppelte Metrologielaser für den Einsatz in Nanopositionier- und Nanomessmaschinen. - In: Messunsicherheit praxisgerecht bestimmen - Prüfprozesse in der industriellen Praxis 2021, (2021), S. 209-222
https://doi.org/10.51202/9783181023907-209
Steifigkeitskalibrierung von Cantilevern : rückführbares Messen der Kraft-Weg-Kennline. - In: Messunsicherheit praxisgerecht bestimmen - Prüfprozesse in der industriellen Praxis 2021, (2021), S. 189-196
https://doi.org/10.51202/9783181023907-189
Nach der Neudefinition des Kilogramms: Darstellung kleiner Kräfte. - In: Messunsicherheit praxisgerecht bestimmen - Prüfprozesse in der industriellen Praxis 2021, (2021), S. 147-157
https://doi.org/10.51202/9783181023907-147
Unsicherheitsbetrachtungen zur Charakterisierung von Mikrokugeln auf Basis von AFM-Oberflächenscans. - In: Messunsicherheit praxisgerecht bestimmen - Prüfprozesse in der industriellen Praxis 2021, (2021), S. 121-132
https://doi.org/10.51202/9783181023907-121
Implementation options of control systems for a cantilever calibration device. - In: Proceedings of 2021 IV International Conference on Control in Technical Systems (CTS), (2021), S. 3-6
The article describes global approaches to control of the cantilever calibration device. The idea of the device consists in electromagnetic compensation of the influence of cantilever forces. The development of regulators is based on the simulation of mechanical processes when the cantilever is applied to the load cell with the principle of electromagnetic compensation; the identification of the processes is performed. In addition, in the course of the study, a comparison was made of PID controllers implemented on various actuator systems: an analog circuit, a current source, a dSPACE real-time system, a microcontroller. The purpose of developing and comparing regulators was to improve characteristics of the system: regulation time, overshoot, noise amplitude.
https://doi.org/10.1109/CTS53513.2021.9562880
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.
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