The Experts below are selected from a list of 1566 Experts worldwide ranked by ideXlab platform
Jürgen Mohr - One of the best experts on this subject based on the ideXlab platform.
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Influence of secondary effects in the fabrication of submicron resist structures using Deep X-Ray Lithography
Journal of Micro Nanolithography MEMS and MOEMS, 2019Co-Authors: A. Faisal, Jürgen Mohr, Thomas Beckenbach, Pascal MeyerAbstract:Background: Deep X-Ray Lithography using synchrotron radiation is a prominent technique in the fabrication of high aspect ratio microstructures. The minimum lateral dimensions producible are limited by the primary dose distribution and secondary effects (Fresnel diffraction, secondary electrons scattering, etc.) during exposure. Aim: The influence of secondary radiation effects on the fabrication of high aspect ratio microstructures with submicrometer lateral dimension by Deep X-Ray Lithography is characterized. Approach: The microstructures under investigation are one-dimensional gratings. The influence of secondary effects on structural dimension is simulated and compared to the experimental results. The quality criteria and possible defects arising in experiments highlight the importance of the mechanical stability of the photoresist. Results: From the simulation results, the minimum period of microstructures that can be produced is about 600 nm. Experimentally, microstructures with 1.2 μm minimum period (resist width of ∼700 nm) and height of ∼10 μm could be fabricated. Conclusions: Simulation results show the feasibility for fabricating gratings with a period less than 1 μm. To achieve these values also in experiment, it is necessary to increase the mechanical stability of the high aspect lamellae. The outcome of these results allows one to reduce the expensive and lengthy product development cycle.
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Deep x ray Lithography processing for batch fabrication of thick polymer based antenna structures
Journal of Micromechanics and Microengineering, 2010Co-Authors: Atabak Rashidian, David M. Klymyshyn, Martin Boerner, Jürgen MohrAbstract:Deep X-Ray Lithography is applied for the first time to fabricate polymer-based antenna structures with different portions of ceramic contents. To produce successful and viable antenna structures, three different methods are proposed using positive and negative tone resists. In the first method the structures are lithographically fabricated avoiding an intermediate molding step using SU-8 as a photosensitive resist filled with fine ceramic powder with particles in the submicron range. In the second and third methods a polymethylmethacrylate (PMMA) mold is first fabricated by X-Ray Lithography, and then SU-8/MMA mixed with the high ceramic powder content is injected into the mold. In these methods a final step of crosslinking for SU-8 and polymerization for MMA is also required. Optimized fabrication parameters allow the production of high quality antenna structures as thick as 2.3 mm. X-Ray Lithography capabilities in fabrication of antennas and other passive microwave components with special features reinforce the idea of fabricating integrated passive microwave circuits along with active circuits using this emerging technology.
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An Ultra-Deep High-Q Microwave Cavity Resonator Fabricated Using Deep X-Ray Lithography
IEICE Transactions on Electronics, 2007Co-Authors: David M. Klymyshyn, Sven Achenbach, Martin Börner, Nina Dambrowsky, Jürgen MohrAbstract:An ultra-Deep polymer cavity structure exposed using Deep X-Ray Lithography is used as a template for metal electroforming to produce a 24-GHz cavity resonator. The metal cavity is 1.8 mm Deep and has impressive structure, including extremely vertical and smooth sidewalls, resulting in low conductor loss. The measured resonator has an unloaded quality factor of above 1800 at a resonant frequency of 23.89 GHz.
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Fabrication of RF MEMS variable capacitors by Deep X-Ray Lithography and electroplating
Microsystem Technologies-micro-and Nanosystems-information Storage and Processing Systems, 2006Co-Authors: Sven Achenbach, David M. Klymyshyn, Darcy T. Haluzan, Timo Mappes, Garth Wells, Jürgen MohrAbstract:Radio frequency micro electro-mechanical systems (RF MEMS) vertical cantilever variable capacitors fabricated using Deep X-Ray Lithography and electroplating are presented. Polymethylmethacrylate (PMMA) layers of 100 μm and 150 μm have been patterned and electroplated with 70 μm and 100 μm thick nickel. A 3 μm thick titanium layer was used as plating base as well as etch time-controlled sacrificial layer for the release of the cantilever beam. The parallel plate layout includes narrow gaps and cantilever beams with an aspect ratio in nickel of up to 60 for 1 mm long features. Auxiliary structures support the beams and gaps during the processing. Room temperature electroplating significantly reduces the risk of deformations compared to the standard process temperature of 52°C. The capacitors operate in the 1–5 GHz range, and demonstrate good RF performance, with quality factors on the order of 170 at 1 GHz for a 1 pF capacitance.
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Kinoform X-Ray lens creation in polymer materials by Deep X-Ray Lithography
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2004Co-Authors: V.p. Nazmov, F. J. Pantenburg, Jürgen Mohr, Leonid Shabel'nikov, E Reznikova, Anatoly Snigirev, Irina Snigireva, S Kouznetsov, M. DimichielAbstract:Abstract Conditions are determined for the formation of X-Ray refractive lenses with kinoform fern-like profile in resist layers of PMMA and SU-8 by Deep X-Ray Lithography. Based on the simulation results of the main steps of mask fabrication and pattern formation the technological process parameters have been defined. The features of microstructure formation in polymer layers more than 100 μm thick are described. The properties of the obtained microstructures have been analyzed. First tests have been performed with SU-8 lenses. The preliminary measured spot size is less a 8.2 μm.
F. J. Pantenburg - One of the best experts on this subject based on the ideXlab platform.
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Instrumentation for Microfabrication with Deep X-Ray Lithography
AIP Conference Proceedings, 2007Co-Authors: F. J. PantenburgAbstract:Deep X‐ray Lithography for microfabrication is performed at least at ten synchrotron radiation centers worldwide. The characteristic energies of these sources range from 1.4 keV up to 8 keV, covering mask making capabilities, Deep X‐ray Lithography up to ultra Deep x‐ray Lithography of several millimeters resist thickness. Limitations in Deep X‐ray Lithography arise from hard X‐rays in the SR‐spectrum leading to adhesion losses of resist lines after the developing process, as well as heat load due to very high fluxes leading to thermal expansion of mask and resist during exposure and therefore to microstructure distortion. Considering the installations at ANKA as an example, the advantages of mirrors and central beam stops for DXRL are presented. Future research work will concentrate on feature sizes much below 1 μm, while the commercialization of DXRL goes in the direction of massive automation, including parallel exposures of several samples in a very wide SR‐fan, developing and inspection.
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Kinoform X-Ray lens creation in polymer materials by Deep X-Ray Lithography
Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2004Co-Authors: V.p. Nazmov, F. J. Pantenburg, Jürgen Mohr, Leonid Shabel'nikov, E Reznikova, Anatoly Snigirev, Irina Snigireva, S Kouznetsov, M. DimichielAbstract:Abstract Conditions are determined for the formation of X-Ray refractive lenses with kinoform fern-like profile in resist layers of PMMA and SU-8 by Deep X-Ray Lithography. Based on the simulation results of the main steps of mask fabrication and pattern formation the technological process parameters have been defined. The features of microstructure formation in polymer layers more than 100 μm thick are described. The properties of the obtained microstructures have been analyzed. First tests have been performed with SU-8 lenses. The preliminary measured spot size is less a 8.2 μm.
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Numerical simulation of thermal distortions in Deep and ultra Deep X-Ray Lithography
Microsystem Technologies, 2003Co-Authors: Sven Achenbach, F. J. Pantenburg, Jürgen MohrAbstract:One major process step in Deep X-Ray Lithography is the exposure of the resist with synchrotron radiation. High energy photons are absorbed in mask, resist and substrate. About 95% of this energy is deposited as thermal heat [Schweizer (1997)]. This may lead to a temperature rise in the system and result in thermal distortions during the patterning process. A sample layout is used to determine the distortions during irradiation. Typical radiation parameters of the ELSA storage ring at Bonn University (2.7 GeV, 35 mA) and material properties are applied to simulate the heat effects. Mask membranes made of titanium or beryllium are modeled to irradiate PMMA layers of 200 and 2500 μm thickness. Copper is used as substrate material. Mask support and the bottom of the substrate are cooled to 21 °C as the system is scanned through the synchrotron beam. In the case of 200 μm PMMA and titanium mask membranes, mask temperatures increase to 40.1 °C, whereas only 22.3 °C are reached if beryllium masks are simulated. Maximum distortions are 0.74 μm for Ti-masks and 0.03 μm for Be-masks. With increasing resist thickness, the incident synchrotron radiation power as well as the temperature rise are reduced. In the case of 2500 μm thick PMMA, temperatures of 21.45 °C are simulated.
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Deep X-Ray Lithography for the fabrication of microstructures at ELSA
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2001Co-Authors: F. J. Pantenburg, J MohrAbstract:Abstract Two beamlines at the Electron Stretcher Accelerator (ELSA) of Bonn University are dedicated for the production of microstructures by Deep X-Ray Lithography with synchrotron radiation. They are equipped with state-of-the-art X-Ray scanners, maintained and used by Forschungszentrum Karlsruhe. Polymer microstructure heights between 30 and 3000 μm are manufactured regularly for research and industrial projects. This requires different characteristic energies. Therefore, ELSA operates routinely at 1.6, 2.3 and 2.7 GeV, for high-resolution X-Ray mask fabrication, Deep and ultra-Deep X-Ray Lithography, respectively. The experimental setup, as well as the structure quality of Deep and ultra Deep X-Ray lithographic microstructures are described.
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Deep X-Ray Lithography beamline at ELETTRA
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 2001Co-Authors: F. Pérennès, F. De Bona, F. J. PantenburgAbstract:Abstract A Deep X-Ray Lithography (DXRL) beamline was just commissioned at ELETTRA in Trieste, the Italian third generation synchrotron light source whose features make it well adapted to the DXRL process. A general description of the beamline is given with an emphasis on the reduction of the effect of secondary emission using a high energy filter based on an horizontal beam-stop. Finally the first fabricated microstructures are presented.
Jost Goettert - One of the best experts on this subject based on the ideXlab platform.
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SU-8-based Deep X-Ray Lithography/LIGA
Proceedings of SPIE, 2003Co-Authors: Linke Jian, Martin Bednarzik, Bernd Loechel, Georg Aigeldinger, Varshni Singh, Gisela Ahrens, Yohannes M. Desta, Jost Goettert, Gabi GruetznerAbstract:Poly-methylmethacrylate (PMMA), a positive resist, is the most commonly used resist for Deep X-Ray Lithography (DXRL)/LIGA technology. Although PMMA offers superior quality with respect to accuracy and sidewall roughness but it is also extremely insensitive. In this paper, we present our research results on SU-8 as negative resist for Deep X-Ray Lithography. The results show that SU-8 is over two order of magnitude more sensitive to X-Ray radiation than PMMA and the accuracy of the SU-8 microstructures fabricated by Deep X-Ray Lithography is superior to UV-Lithography and comparable to PMMA structures. The good pattern quality together with the high sensitivity offers rapid prototyping and direct LIGA capability. Moreover, the combinational use of UV and X-Ray Lithography as well as the use of positive and negative resists made it possible to fabricate complex multi-level 3D microstructures. The new process can be used to fabricate complex multi-level 3D structures for MEMS, MOEMS, Bio-MEMS or other micro-devices.
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Direct fabrication of Deep X-Ray Lithography masks by micromechanical milling
Precision Engineering, 1998Co-Authors: Craig R. Friedrich, Jost Goettert, P. Coane, Niranjan GopinathinAbstract:Micromechanical milling has been shown to be a rapid and direct method for fabricating masks for Deep X-Ray Lithography with lateral absorber features down to 10 micrometers. Conventional X-Ray mask fabrication requires complex processes and equipment, and a faster and simpler method using micromechanical milling was investigated for larger microstructures for mesoscale applications. Micromilled X-Ray masks consisting of a layered architecture of gold and titanium films on graphite yielded exposures in PMMA with accuracy and repeatability suitable for prototype purposes. A method for compensating milling tool radial runout was adapted, and the average accuracy of mask absorber features was 0.65 micrometers, with an average standard deviation of 0.55 micrometers. The milling process leaves some absorber burrs, and the absorber wall is tapered, which introduces an additional process bias. Mask fabrication by micromilling is fast and, therefore, less costly than conventional mask fabrication processes.
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ICMENS - Fabrication of ultra thick, ultra high aspect ratio microcomponents by Deep and ultra Deep X-Ray Lithography
Proceedings International Conference on MEMS NANO and Smart Systems, 1Co-Authors: L. Jian, Martin Bednarzik, Bernd Loechel, Yohannes M. Desta, H.-u. Scheunemann, Jost GoettertAbstract:Two advanced processes have been developed for fabricating ultra thick and ultra high aspect ratio (HAR) microstructures. One is the SU-8 based Deep X-Ray Lithography (SU-8 based DXRL) process which uses the normal Deep X-Ray beam to expose the negative SU-8 resist. Another one is wave length shifter(WLS) based Ultra Deep X-Ray Lithography (WLS-UDXRL) process which uses special ultra Deep X-Ray beam from wave length shifter to expose the positive PMMA resist. For SU-8 based DXRL process, the typical exposure time of a layer of SU-8 is about 1% of that of PMMA. Even for a few millimeters thick resists the exposure time are just a few minutes. In WLS-UDXRL process, the X-Ray beam is strengthened by a wave length shifter(WLS) so the required exposure time for ultra thick PMMA is reduced greatly. In the paper, the characteristic of the these two processes are discussed and the examples of the ultra thick and ultra HAR microstructures fabricated by these processes are presented (ultra thick up to 3600 /spl mu/m and HAR up to 360).
Anja Voigt - One of the best experts on this subject based on the ideXlab platform.
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Development and characterization of ultra high aspect ratio microstructures made by ultra Deep X-Ray Lithography
Journal of Materials Processing Technology, 2015Co-Authors: Vladimir Nazmov, Joachim Schulz, Juergen Mohr, Elena Reznikova, Anja VoigtAbstract:Abstract A technique of casting of thick pre-polymer layers was developed based on the proposed model of diluent evaporation. For the first time, microstructures with 7 mm height and up to 18 microns wide (an aspect ratio of up to 389) were manufactured by means of ultra Deep X-Ray Lithography in a cured pre-polymer that can be functionalized. The microstructures were characterized. The difference in the size of patterned microstructures and their initial size on the X-Ray mask decreases to 400 nm with the lessening lateral dimension of the microstructures from 1500 to 18 μm. The sidewall roughness also decreases to 20 nm.
Benedetta Marmiroli - One of the best experts on this subject based on the ideXlab platform.
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Top-down patterning of Zeolitic Imidazolate Framework composite thin films by Deep X-Ray Lithography
Chemical communications (Cambridge England), 2012Co-Authors: Constantinos Dimitrakakis, Benedetta Marmiroli, Heinz Amenitsch, Luca Malfatti, Anita J. Hill, Plinio Innocenzi, Gianluca Grenci, Lisa Vaccari, Bradley P. Ladewig, Matthew R. HillAbstract:For the first time a top-down process was used to control the spatial location of Metal–Organic Frameworks on a surface. Deep X-Ray Lithography was utilised to micropattern a Zeolitic Imidazolate Framework layer on a sol–gel surface, with exposure hardening the sol–gel by inducing crosslinking while leaving the frameworks intact.
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Microfabrication of mesoporous silica encapsulated enzymes using Deep X-Ray Lithography
Journal of Materials Chemistry, 2012Co-Authors: Cara M. Doherty, Yuan Gao, Benedetta Marmiroli, Heinz Amenitsch, Fabio Lisi, Luca Malfatti, Kenji Okada, Masahide Takahashi, Anita J. Hill, Plinio InnocenziAbstract:A bottom-up enzyme encapsulation technique on mesoporous silica together with top-down Deep X-Ray Lithography provides a novel fabrication method for producing bioactive mesoporous patterned substrates for potential use as a biosensing platform. This precise, spatially controllable functionalisation technique is promising for micro-fluidic or lab-on-a-chip type devices.
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Deep X‐ray Lithography for Direct Patterning of PECVD Films
Plasma Processes and Polymers, 2010Co-Authors: Stefano Costacurta, Benedetta Marmiroli, Heinz Amenitsch, Luca Malfatti, Gianluca Grenci, Alessandro Patelli, Paolo Falcaro, Massimo Piccinini, Plinio InnocenziAbstract:An advanced lithographic technique which is based on direct writing of thin films by hard X-Rays has been developed. Silica hybrid organic–inorganic films have been deposited by radio frequency plasma-enhanced chemical vapour deposition and have been patterned using Deep X-Ray Lithography with synchrotron light. The exposure to high energy photons removed the organic groups in the films and induced densification of the silica network. The films, after lithographic writing, can be easily chemically etched to obtain well-defined patterns of high quality. By tuning the exposure dose it is possible modulating the structure and the properties of the final material. The overall Lithography process can be achieved in two steps, writing by X-Rays and chemical etching, therefore employing the hybrid film directly as resist without employing any other intermediate step. The films and the patterned structures have been characterized by ellipsometric spectroscopy, scanning electron microscopy, atomic force microscopy, contact angle measurements, Fourier transform infrared spectroscopy, infrared imaging and Rutherford backscattering.
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Patterning block copolymer thin films by Deep X-Ray Lithography
Soft Matter, 2010Co-Authors: Plinio Innocenzi, Benedetta Marmiroli, Stefano Costacurta, Paolo Falcaro, Tongjit Kidchob, Fernando Cacho-nerin, Heinz AmenitschAbstract:Developing fast, cheap and reliable micro and nanofabrication technologies for block copolymer thin films is a key issue for exploiting the wide potential applications of this class of materials. We have used a synchrotron source of high energy photons (hard X-Rays) for developing a lithographic tool that allows direct writing of block-copolymer thin films. We have exposed films prepared by a tri-block copolymer, Pluronic F127, to increasing doses of radiation to evaluate the effect of high energy X-Rays on the samples. The as-deposited films show a crystalline structure due to the crystallization of polyethylene oxide chains in Pluronic F127; the exposure to low doses causes a phase change from crystalline to amorphous, as is shown by infrared spectroscopy. Another effect of the exposure to X-Rays of the block copolymer films is the surface roughness reduction which has been observed by atomic force microscopy, At higher doses the X-Rays erase the film from the substrate allowing the formation of patterned polymeric structures. Deep X-Ray Lithography has proved to be a very effective tool to pattern block copolymer films by a direct, top-down method.
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Low cost transparent SU-8 membrane mask for Deep X-Ray Lithography
Microsystem Technologies-micro-and Nanosystems-information Storage and Processing Systems, 2005Co-Authors: Stefano Cabrini, F. Pérennès, Benedetta Marmiroli, Alessandro Olivo, Alessandro Carpentiero, R. Kumar, P. Candeloro, E. Di FabrizioAbstract:Deep X-Ray Lithography masks require good transparency and mechanical resistance to the intense synchrotron X-Ray beam, large active areas (cm)2 and compatibility with the standard fabrication processes (optical Lithography and gold electroforming). Moreover higher resolution can be achieved with low roughness flat membrane. Furthermore multiple aligned exposures require an optically transparent material. Diamond like Carbon membranes fulfill those requirements but have a prohibitive cost. Our approach consists in using an SU-8 epoxy resin layer as membrane material. In this communication the different steps of the fabrication process will be presented, as well as the results obtained using the mask for particular applications.
