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SMV-2013-01: Reliéfní struktury na principu diftraktivní optiky
Horáček, Miroslav ; Kolařík, Vladimír ; Matějka, Milan ; Urbánek, Michal ; Krátký, Stanislav ; Chlumská, Jana ; Král, Stanislav
Výzkum a vývoj v oblasti fyzikální realizace grafických a optických struktur na principu difraktivní optiky prostředky elektronové litografie v záznamovém materiálu neseném křemíkovou nebo skleněnou deskou. Výzkum zahrnuje analýzu grafického resp. optického motivu, výzkum a aplikaci reliéfních struktur realizujících požadované grafické resp. optické vlastnosti, výzkum a modelování možností fyzikální realizace reliéfních struktur, vypracování a analýzu technologie realizace reliéfní struktury s ohledem na limity současných vědeckých přístrojů, ověření teoretických úvah expozicí vzorku reliéfní struktury.
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Structural Color of Metallic Surfaces
Kolařík, Vladimír ; Horáček, Miroslav ; Urbánek, Michal ; Matějka, Milan ; Krátký, Stanislav ; Chlumská, Jana ; Bok, Jan
Nano structuring of metallic surfaces shows surface colors unusual for a given material. This study presents an overview of possible approaches to achieve desirable color changes. The nano structured relief structures prepared by means of electron beam lithography process are presented. Optical design and simulation of optical properties, data preparation for e-beam patterning, parameters of the writing process, and technological issues are presented in detail. Finally, real examples of structures that exhibit surface color changes are presented and discussed.
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Some Other Gratings: Benchmarks for Large-Area E-Beam Nanopatterning
Meluzín, Petr ; Horáček, Miroslav ; Urbánek, Michal ; Bok, Jan ; Krátký, Stanislav ; Matějka, Milan ; Chlumská, Jana ; Kolařík, Vladimír
E-beam lithography is a flexible technology for diffraction gratings origination. Nevertheless, requirements of the high optical quality of large area diffractive structures imply various severe challenges to e-beam delineating processes. This paper summarizes the e-beam process parameters that influence the quality of large area grating structures. Next, we propose some new methods to prepare diffraction gratings that were found to be useful for testing and benchmarking purposes. Those methods include single line gratings, labyrinth structures, fractional structures, tiling patterns, quasi regular filling structures and forked line structures. Various samples were prepared with the standard and newly developed e-beam patterning processes using both e-beam writers available: one with the Gaussian beam at 100 keV and another one with the shaped beam at 15 keV. Some of the results are presented further in this paper, their variants and parameters are discussed as well as their usefulness as benchmarking e-beam patterns for large area optical structures, elements and devices.
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Exposure Time Comparison between E-beam Writer with Gaussian Beam and Variable Shaped Beam
Horáček, Miroslav ; Krátký, Stanislav ; Urbánek, Michal ; Kolařík, Vladimír ; Meluzín, Petr ; Matějka, Milan ; Chlumská, Jana
One of the main goals in e-beam lithography is to increase exposure speed to achieve higher throughput. There are basically two types of electron-beam writers, shaped beam lithography systems and Gaussian beam lithography systems. The exposure time of both e-beam writers consist in essence of beam-on time, deflection system stabilization time and stage movement time. Exposure time testing was carried out on two types of patterns. There were completely filled in areas, binary period gratings (ratio 1:1 between exposed and unexposed areas), and multileveled structures (computer generated holograms). Exposures data was prepared according to standard technology (PMMA resist, exposure dose, non-alcoholic based developer) for both systems. The result of experiment shows that variable shaped beam system has advantage in multileveled structures while the Gaussian beam system is more suitable for gratings type of pattern. It was proved that combination of both systems has its use to increase exposures throughput.
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Fázové masky vyrobené elektronovou litografií a iontovým leptáním pro přípravu vláken s braggovými mřížkami
Krátký, Stanislav ; Urbánek, Michal ; Kolařík, Vladimír ; Horáček, Miroslav ; Chlumská, Jana ; Matějka, Milan ; Šerý, Mojmír ; Mikel, Břetislav
Braggovská vláknová mřížka je založena na principu lokální změny indexu lomu ve vlákně optického vlákna. Má širokou aplikační oblast, používá se např. pro různé typy filtrů v komunikacích, může se též použít v oblasti snímačů mechanického namáhání. Pro přípravu tohoto typu mřížek lze použít různé technologie. Například, index lomu je možné modifikovat přímo při výrobě optického vlákna. Dále, mřížka může být exponována bod po bodu laserovým svazkem. Nejefektivnějším způsobem je expozice přes fázovou masku, neboť jednu masku lze použít pro výrobu stovek mřížek (i když kvalita masky se při expozicích postupně snižuje, ačkoliv je připravena v křemenném skle). Tento příspěvek se zabývá různými přístupy pro přípravu fázových masek z pohledu vlivu na kvalitu exponovaných Braggovských mřížek. Mřížková fázová maska je definována zejména dvěma parametry; periodou a hloubkou (předpokládáme střídu 1:1 mezi výstupky a prohlubněmi mřížky).
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Monte-Carlo simulation of proximity effect in e-beam lithography
Urbánek, Michal ; Kolařík, Vladimír ; Krátký, Stanislav ; Matějka, Milan ; Horáček, Miroslav ; Chlumská, Jana
E–beam lithography is the most used pattern generation technique for academic and research prototyping. During this patterning by e–beam into resist layer, several effects occur which change the resolution of intended patterns. Proximity effect is the dominant one which causes that patterning areas adjacent to the beam incidence point are exposed due to electron scattering effects in solid state. This contribution deals with Monte Carlo simulation of proximity effect for various accelerating beam voltage (15 kV, 50 kV, 100 kV), typically used in e–beam writers. Proximity effect simulation were carried out in free software Casino and commercial software MCS Control Center, where each of electron trajectory can be simulated (modeled). The radial density of absorbed energy is calculated for PMMA resist with various settings of resist thickness and substrate material. At the end, coefficients of proximity effect function were calculated for beam energy of 15 keV, 50 keV and 100 keV which is desirable for proximity effect correction.
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Comparison of ultimate resolution achieved by e-beam writers with shaped beam and with Gaussian beam
Krátký, Stanislav ; Kolařík, Vladimír ; Matějka, Milan ; Urbánek, Michal ; Horáček, Miroslav ; Chlumská, Jana
This contribution deals with the comparison of two different e–beam writer systems. E–beam writer with rectangular shaped beam BS600 is the first system. This system works with electron energy of 15 keV. Vistec EBPG5000+ HR is the second system. That system uses the Gaussian beam for pattern generation and it can work with two different electrons energies of values 50 keV and 100 keV. The ultimate resolution of both systems is the main aspect of comparison. The achievable resolution was tested on patterns consisted of single lines, single dots (rectangles for e–beam writer with shaped beam) and small areas of periodic gratings. Silicon wafer was used as a substrate for resist deposition. Testing was carried out with two resists, PMMA as a standard resist for electron beam lithography, and HSQ resist as a material for ultimate resolution achievement. Process of pattern generation (exposition) is affected by the same undesirable effect (backscattering and forward scattering of electrons, proximity effect etc.). However, these effects contribute to final pattern (resolution) by various dispositions. These variations caused the different results for similar conditions (the same resist, dose, chemical developer etc.). Created patterns were measured and evaluated by using of atomic force microscope and scanning electron microscope.
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Lift-Off technique using different e-beam writers
Chlumská, Jana ; Kolařík, Vladimír ; Krátký, Stanislav ; Matějka, Milan ; Urbánek, Michal ; Horáček, Miroslav
This paper deals with lift–off technique performed by the way of electron beam lithography. Lift–off is a technique mainly used for preparation of metallic patterns and unlike etching it is an additive technique using a sacrificial material – e.g. e–beam resist PMMA. In this paper we discussed technique of preparation of lift–off mask on two different e–beam writing systems. The first system was BS600 – e–beam writer with rectangular variable shaped beam working with 15keV. The second system was Vistec EBPG5000+ HR – e–beam writer with Gaussian shape beam working with 50 keV and 100 keV. The PMMA resist single layer and bi–layer was used for the lift–off mask preparation. As a material for creation of metallic pattern, magnetron sputtered chromium was used. Atomic force microscope, scanning electron microscope and contact profilometer were used to measure and evaluate the results of this process.
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Microstructuring of metallic layers for sensor applications
Kolařík, Vladimír ; Krátký, Stanislav ; Urbánek, Michal ; Matějka, Milan ; Chlumská, Jana ; Horáček, Miroslav
This contribution deals with a patterning of thin metallic layers using the masking technique by electron beam lithography. It is mainly concentrated on procedures to prepare finger structure in thin Gold layer on electrically isolated Silicon wafer. Both positive and negative tone resists are used for patterning. The thin layer is structured by the wet etching or by the lift-off technique. The prepared structures are intended to be used as a conductivity sensor for a variety of sensor applications. Patterning of the thin layer is performed by the e-beam writer with shaped rectangular beam BS600 by direct writing (without the glass photo mask). Besides the main technology process based on the direct-write e-beam lithography, other auxiliary issues are also discussed such as stitching and overlay precision of the process, throughput of this approach, issues of the thin layer adhesion on the substrate, inter-operation control and measurement techniques.
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