Fertigung laminarer optischer Gitter am HZB

Laminare optische Gitter stellen höchste Anforderungen an die mikrosystemtechnische Fertigung der Mikro und Nano strukturen in Hinsicht auf Präzision und Homogenität. Im Rahmen des EU Projektes Aufbau eines Technologiezent rums für hocheffiziente optische Präzisionsgitter am Helmholtz Zentrum Berlin HZB EFRE Vertrag Nr. 20072013 2 43 [1,2] wurden die für die Herstellung von laminaren und geblazten Gittern notwendigen Anlagen in Betrieb ge nommen. Gleichzeitig wurde mit der Prozessentwicklung begonnen. In diesem Artikel werden die neuesten Prozessergebnisse von durch Laserinterferenzlithographie LIL in Photoresist erzeugter Gitterstrukturen und deren nur wenige Nanometer tiefe Übertragung in Siliziumsubstrate mittels Ionenstrahl ätzen vorgestellt. english version Laminar optical gratings impose highest demands on microsystem technological manufacturing with regard to precision and uniformity. Within the project Installation of a technology centre for highly efficient precision gratings at Helm holtz Zentrum Berlin HZB EFRE Vertrag Nr. 20072013 2 43 [1,2] the necessary systems for the manufacturing of laminar and blazed gratings were taken into operation and process development has started. In this article we present the results of grating structures manufactured with laser interference lithography and subse quent ion beam etchin

Scatterometry reference standards to improve tool matching and traceability in lithographical nanomanufacturing

High quality scatterometry standard samples have been developed to improve the tool matching between different scatterometry methods and tools as well as with high resolution microscopic methods such as scanning electron microscopy or atomic force microscopy and to support traceable and absolute scatterometric critical dimension metrology in lithographic nanomanufacturing. First samples based on one dimensional Si or on Si 3 N 4 grating targets have been manufactured and characterized for this purpose. The etched gratings have periods down to 50 nm and contain areas of reduced density to enable AFM measurements for comparison. Each sample contains additionally at least one large area scatterometry target suitable for grazing incidence small angle X ray scattering. We present the current design and the characterization of structure details and the grating quality based on AFM, optical, EUV and X Ray scatterometry as well as spectroscopic ellipsometry measurements. The final traceable calibration of these standards is currently performed by applying and combining different scatterometric as well as imaging calibration methods. We present first calibration results and discuss the final design and the aimed specifications of the standard samples to face the tough requirements for future technology nodes in lithography

Gratings for synchrotron and FEL beamlines a project for the manufacture of ultra precise gratings at Helmholtz Zentrum Berlin

Blazed gratings are of dedicated interest for the monochromatization of synchrotron radiation when a high photon flux is required, such as, for example, in resonant inelastic X ray scattering experiments or when the use of laminar gratings is excluded due to too high flux densities and expected damage, for example at free electron laser beamlines. Their availability became a bottleneck since the decommissioning of the grating manufacture facility at Carl Zeiss in Oberkochen. To resolve this situation a new technological laboratory was established at the Helmholtz Zentrum Berlin, including instrumentation from Carl Zeiss. Besides the upgraded ZEISS equipment, an advanced grating production line has been developed, including a new ultra precise ruling machine, ion etching technology as well as laser interference lithography. While the old ZEISS ruling machine GTM 6 allows ruling for a grating length up to 170 mm, the new GTM 24 will have the capacity for 600 mm 24 inch gratings with groove densities between 50 lines mm 1 and 1200 lines mm 1. A new ion etching machine with a scanning radiofrequency excited ion beam HF source allows gratings to be etched into substrates of up to 500 mm length. For a final at wavelength characterization, a new reflectometer at a new Optics beamline at the BESSY II storage ring is under operation. This paper reports on the status of the grating fabrication, the measured quality of fabricated items by ex situ and in situ metrology, and future development goal

Computational strategies to combat COVID-19: useful tools to accelerate SARS-CoV-2 and coronavirus research

SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) is a novel virus of the family Coronaviridae. The virus causes the infectious disease COVID-19. The biology of coronaviruses has been studied for many years. However, bioinformatics tools designed explicitly for SARS-CoV-2 have only recently been developed as a rapid reaction to the need for fast detection, understanding and treatment of COVID-19. To control the ongoing COVID-19 pandemic, it is of utmost importance to get insight into the evolution and pathogenesis of the virus. In this review, we cover bioinformatics workflows and tools for the routine detection of SARS-CoV-2 infection, the reliable analysis of sequencing data, the tracking of the COVID-19 pandemic and evaluation of containment measures, the study of coronavirus evolution, the discovery of potential drug targets and development of therapeutic strategies. For each tool, we briefly describe its use case and how it advances research specifically for SARS-CoV-2. All tools are free to use and available online, either through web applications or public code repositories.Peer Reviewe

X ray absorption spectroscopy using a self seeded soft X ray free electron laser

X ray free electron lasers XFELs enable unprecedented new ways to study the electronic structure and dynamics of transition metal systems. L edge absorption spectroscopy is a powerful technique for such studies and the feasibility of this method at XFELs for solutions and solids has been demonstrated. However, the required x ray bandwidth is an order of magnitude narrower than that of self amplified spontaneous emission SASE , and additional monochromatization is needed. Here we compare L edge x ray absorption spectroscopy XAS of a prototypical transition metal system based on monochromatizing the SASE radiation of the linac coherent light source LCLS with a new technique based on self seeding of LCLS. We demonstrate how L edge XAS can be performed using the self seeding scheme without the need of an additional beam line monochromator. We show how the spectral shape and pulse energy depend on the undulator setup and how this affects the x ray spectroscopy measurement

Prozessoptimierung zur Herstellung von zweidimensionalen photonischen Kristallen mittels Nanoimprint Lithografie

For the fabrication of two dimensional photonic crystals, usually the electron beam lithography is used. Because of the long processing time and high costs, the electron beam lithography is not suitable for mass production. An alternative method is the nanoimprint lithography. In this process, a structured stamp is moulded in a thermoplastic resist under the use of force and temperature. The produced structure can be transferred into the substrate below. A difficulty of this process is the simultaneous patterning of micro and nanostructures. This results from the hole diameters of the photonic crystals 80nm and the waveguides 50 m . In this paper, a process optimization is presented which allows the production of these multiscale structures. At the end, the characteristics of the photonic crystals could be measured and the results are compared with a simulation. It could be shown that high quality photonic crystals can be produced using this metho

Fabrication of high aspect ratio nanostructures on 3D surfaces

A combination of different materials and processes was used to create high aspect ratio nanostructures on 3D surfaces. The high aspect ratio structures were formed on thermoplastic foils using UV Nanoimprintlithography UV NIL with a poly dimethylsiloxane PDMS stamp which was fabricated by soft lithography. An epoxy mixture with a higher glass transition temperature than the thermoplastic foil was used as a resist for UV NIL. The hydrophobicity of structured substrates was characterized by the surface contact angle. Substrates with an additional chemical treatment were also produced and characterized. Results of contact angle measurement showed that superhydrophobic surface properties can be obtained with structured and chemically treated samples. The foils were further used as a substrate in a thermoforming process to transfer the structures into a microchannel. Using this process, 3D structured foils can be fabricated with high accuracy. The foils were used as a master structure for a replica molding process which allowed the fabrication of 3D structured polymer parts. With the presented method, microchannels with superhydrophobic surface properties can be fabricate