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Electrostatic Deflection and Correction Systems
Badin, Viktor ; Oral, Martin (referee) ; Zlámal, Jakub (advisor)
The aim of this master's thesis is to explore and study dynamic aberration correction options in electron-beam lithography systems. For the calculations, the thesis uses the optical column of the BS600 electron-beam writer. The thesis focuses on corrections of the third order field curvature, astigmatism, and distortion aberrations of the currently used magnetic deflection system and a newly designed electrostatic deflection system. The parameters of the two deflection and correction systems were compared.
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Parasitic Aberrations of Electrostatic Deflectors
Badin, Viktor ; Radlička, Tomáš (referee) ; Sháněl, Ondřej (referee) ; Lencová, Bohumila (advisor)
Tato disertační práce se zabývá parazitickými aberacemi elektrostatických multipólových optických prvků vznikajícími v důsledku nepřesného seřízení elektrod. Přesnost výroby a seřízení mechanických částí může mít významný vliv na rozlišení elektronových mikroskopů a litografických systémů. Nepřesnosti výroby, chyby justáže a všechna další narušení symetrie generují takzvaná parazitická pole, jejichž účinky na elektronový svazek se označují jako vady seřízení. Poruchy osově souměrných čoček se obvykle řeší pomocí Sturrockova principu. Posunutí nebo naklonění celých multipólových prvků lze analyzovat v globálně posunutém nebo nakloněném souřadnicovém systému. Tato práce se zabývá vadami seřízení jednotlivých elektrod, které nelze jednoduše popsat zmíněnými přístupy, a obvykle je potřeba je řešit ve 3D. Výpočty ve 3D jsou obecně pomalejší a mají vyšší výpočetní nároky než 2D nástroje standardně používané v softwaru pro částicovou optiku. Pro výpočet parazitických polí generovaných nesprávně seřízenými elektrodami byla v této práci vyvinuta 2D perturbační metoda, kompatibilní s metodou konečných prvků, založená na lokálním posunutí souřadného systému u perturbované elektrody. Byly studovány nepřesnosti vzniklé posuvem elektrody v každé ose cylindrického souřadného systému (podélné, radiální a azimutální). Dále byly ukázány možné aplikace odvozené obecné metody, např. elipticita a příčný posun celého deflektoru. Pro každý z těchto případů jsou výsledné parazitické osové potenciály vypočítané 2D metodou a porovnány s 3D řešením. Kromě srovnání parazitických osových potenciálů byl také ukázán vliv vad seřízení na stopu elektronového svazku procházející optickou soustavou elektronového litografu. Ověření 3D výpočtem bylo v dobré shodě s 2D metodou. Navržený způsob výpočtu parazitických polí ve 2D umožňuje porozumět vlivům různých výrobních a montážních tolerancí, charakterizovat tyto vlivy, navrhnout zařízení potřebná pro korekci vzniklých aberací a optimalizovat požadavky na mechanické tolerance. Vyvinutá metoda je použitelná na jakémkoli standardním PC a je o 1--2 řády rychlejší než řešení porušeného systému ve 3D.
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Recent Trends in Charged Particle Optics and Surface Physics Instrumentation. Proceedings of the 16th International Seminar
Mika, Filip ; Pokorná, Zuzana
The origins of the seminar “Recent Trends in Charged Particle Optics and Surface Physics Instrumentation” date back into the eighties, when as a part of the isolated “Eastern Bloc”, we were short of English-language books, papers and conferences. In 1990, at the second Seminar, there were as many as 30 participants from 5 countries. The third Seminar in 1992 was moved to hotel Skalský dvur in the Bohemian-Moravian Highlands where it has been held as a biannual meeting ever since.\nThe Seminar takes place in a secluded lakeside hotel surrounded by beautiful nature and calm forests, so all participants have a great possibility to see each other every day and to discuss their topics of interest in more detail. This is a great advantage compared to the huge bustling conferences with their many parallel sections, which are a lively celebration of science but\nsometimes it is difficult to meet there the person with whom you want to discuss a particular scientific topic in more detail.\nFrom the very beginning, the Seminar has been conceived as a meeting devoted more to asking questions not answered yet, than to reporting results. This spirit is usually less present in the introductory presentations and posters but is dominant in the following discussions.\n
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Electrostatic Deflection and Correction Systems
Badin, Viktor ; Oral, Martin (referee) ; Zlámal, Jakub (advisor)
The aim of this master's thesis is to explore and study dynamic aberration correction options in electron-beam lithography systems. For the calculations, the thesis uses the optical column of the BS600 electron-beam writer. The thesis focuses on corrections of the third order field curvature, astigmatism, and distortion aberrations of the currently used magnetic deflection system and a newly designed electrostatic deflection system. The parameters of the two deflection and correction systems were compared.
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9th International Conference on Charged Particle Optics. Book of Abstracts
Mika, Filip ; Pokorná, Zuzana
The series of conferences on charged-particle optics was launched in 1980 by Hermann Wollnik together with the late Karl Brown and myself in an attempt to bring together the three main CPO communities, accelerator optics, spectrometer optics and electron optics. All three groups were pleased and somewhat surprised to discover how much they had in common, and it was decided to continue to meet at regular intervals. The fact that so many contributions have been submitted to this ninth meeting shows that the formula is as attractive as ever and the organisers have succeeded in producing a balanced programme with much original material in each of the domains of interest. Brno is well known for major contributions to software for CPO and for low-voltage scanning electron microscopy. There have been exciting developments in all the areas covered by the conference. In electron optics, the successful implementation of aberration correctors for electron microscopes has dominated the literature for the last few years but other aspects of the subject have not been neglected; a session is devoted to ion optics. The optics of accelerators and mass and energy spectrometers is likewise providing many surprises. These proceedings provide a unique snapshot of the world of charged-particle optics in 2014.
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Computations in Charged Particle Optics
Oral, Martin ; Radlička, Tomáš
The design of modern electron microscopes could not be possible without appropriate software tools. With the sub-nanometer resolution in SEM, and the sub-ångström resolution in TEM, one can see that the simulations involved in designing the instruments need to be tremendously accurate. A simulation starts with the computation of the electric and magnetic fields generated by various optical elements. That is followed by determinig the paraxial properties, aberrations and accurate particle trajectories (ray tracing). The distributions of the fields are mostly detemined with the Finite Element Method (FEM), the Boundary Element Method (BEM) or the Finite Difference Method (FDM). As the field data are at the input of all the subsequent calculations, they need to be very accurate, especially in the region close to the optical axis. Current expertise includes a set of rules that need to be applied in generating a FEM or BEM mesh. Advanced field interpolation techniques are necessary for accurate aberration analysis and particle tracing with high-order integration methods. Specialized software has been developped for the use in charged particle optics which aids the user in getting meaningful and accurate results. For instance, the EOD (Electron Optical Design) is a comprehensive package for particle optical sumulations. Field data produced by SIMION and Comsol need a specialized post-processing before their use in accurate ray tracing. Presented will be different methods of computing the optical aberrations, intensity distribution and probe size (resolution) on basic as well as more advanced examples (electron and ion optical columns, deflection systems, ToF spectrometers etc.) that were solved in the EOD and using custom programs.
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Současné trendy v elektronové optice a přístrojové technice pro povrchovou fyziku
Mika, Filip
Proceedings of seminar on Recent Trends in Charged Particle Optics and Surface Physics Instrumentation. The seminar was held in Skalsky Dvur hotel on July 14 – 18, 2008. The seminar is periodically prepared by ISI AS CR v.v.i., Department of Electron Optics and it is a traditional opportunity for scientific discussion of topics regarding creation and formation of charged particles beams and its usage.
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