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Heusinger M.,Fraunhofer Institute for Applied Solid State Physics | Banasch M.,Vistec Electronic Beam GmbH | Flugel-Paul T.,Fraunhofer Institute for Applied Optics and Precision Engineering | Zeitner U.D.,Fraunhofer Institute for Applied Solid State Physics | Zeitner U.D.,Fraunhofer Institute for Applied Optics and Precision Engineering
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2016

Any violation of the periodicity of a perfect grating will result in diffuse scattering. In the particular case of a periodic violation the generated stray light shows deterministic, also periodic features that arise as distinct peaks in the stray light spectra, especially so-called Rowland ghosts. In this paper the characteristics of the spurious Rowland ghosts in binary spectrometer gratings are investigated and the potential of a randomization technique in order to suppress the Rowland ghosts is analyzed. Especially in sequential fabrication technologies, e.g. electron beam lithography, the Rowland ghosts originate in a segmentation process that is necessary in order to write large scale gratings. Hence several subareas are subsequentially exposed and stitched together leading to the final full size grating. Due to this stitching approach the subareas induce secondary periodic structures and thus generate the spurious Rowland ghosts in the order of magnitude of <10-4 compared to the useful diffraction order. A randomization of this segmentation process is investigated both theoretically in rigorous simulations and experimentally by fabricating a purposely designed optical grating. As approach for the randomization in experiment we applied a special multi-pass-exposure. Here the sample is exposed multiple times with an accordingly shifted and dose-reduced subarea in each pass. The achieved simulation results show that a randomization of the subareas effectively reduces the Rowland ghosts. Furthermore the applied randomization technique during grating fabrication was able to suppress one kind of Rowland ghosts completely. © 2016 SPIE.


Hahmann P.,Vistec Electronic Beam GmbH | Boettcher M.,Vistec Electronic Beam GmbH | Klein M.W.,Vistec Electronic Beam GmbH | Stolberg I.A.,Vistec Electronic Beam GmbH | Weidenmueller U.,Vistec Electronic Beam GmbH
Microelectronic Engineering | Year: 2010

Microelectronic technology inevitably continues to develop towards ever shrinking, smaller geometries. For the year 2016, minimum feature sizes requiring 22 nm half pitch (hp) patterning lithography are predicted. To keep abreast of this challenging development, Vistec's latest variable shaped beam (VSB) column - already described elsewhere [1] - was applied and the electron energy level increased to 100 keV for exposure of such fine pattern dimensions. Based on the electron-optical simulations that were performed, resolving power can be forecast to improve by a factor of 1.4 compared to results reported earlier. This is what 22 nm hp exposure requires as a compulsory precondition. This paper discusses four types of resist to demonstrate the increase in resolution capability. These are: positive and negative tone resists, conventional resists and chemically amplified resists. To provide a sound evaluation, several test patterns containing single lines, groups of seven lines and spaces, as well as extensive line/space areas and contact arrays were exposed. Top-down SEM images and cross-sectional views were both taken into account for a final assessment. It turned out that only the conventional resists are able to deliver the resolution capability for hp 22 nm. © 2009 Elsevier B.V. All rights reserved.


Slodowski M.,Vistec Electronic Beam GmbH | Doering H.-J.,Vistec Electronic Beam GmbH | Dorl W.,Vistec Electronic Beam GmbH | Stolberg I.A.,Vistec Electronic Beam GmbH
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2011

According to the ITRS [1] photo mask is a significant challenge for the 22nm technology node requirements and beyond. Mask making capability and cost escalation continue to be critical for future lithography progress. On the technological side mask specifications and complexity have increased more quickly than the half-pitch requirements on the wafer designated by the roadmap due to advanced optical proximity correction and double patterning demands. From the economical perspective mask costs have significantly increased each generation, in which mask writing represents a major portion. The availability of a multi-electron-beam lithography system for mask write application is considered a potential solution to overcome these challenges [2, 3]. In this paper an update of the development status of a full-package high-throughput multi electron-beam writer, called Multi Shaped Beam (MSB), will be presented. Lithography performance results, which are most relevant for mask writing applications, will be disclosed. The MSB technology is an evolutionary development of the matured single Variable Shaped Beam (VSB) technology. An arrangement of Multi Deflection Arrays (MDA) allows operation with multiple shaped beams of variable size, which can be deflected and controlled individually [4]. This evolutionary MSB approach is associated with a lower level of risk and a relatively short time to implementation compared to the known revolutionary concepts [3, 5, 6]. Lithography performance is demonstrated through exposed pattern. Further details of the substrate positioning platform performance will be disclosed. It will become apparent that the MSB operational mode enables lithography on the same and higher performance level compared to single VSB and that there are no specific additional lithography challenges existing beside those which have already been addressed [1]. © 2011 SPIE.


Kley E.-B.,Friedrich - Schiller University of Jena | Schmidt H.,Friedrich - Schiller University of Jena | Zeitner U.,Fraunhofer Institute for Applied Optics and Precision Engineering | Banasch M.,Vistec Electronic Beam GmbH | Schnabel B.,Vistec Electronic Beam GmbH
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2012

The pattern generation for nano-optics raises high demands on resolution, writing speed and flexibility: nearly arbitrary complex structures with feature sizes below 100 nm should be realized on large areas up to 9 inches in square within reasonable time. With e-beam lithography the requirements on resolution and flexibility can be fulfilled but the writing time becomes the bottle neck. Acceleration by Variable Shaped Beam (VSB) writing principle (geometrical primitives with flexible size can be exposed with a single shot) is sometimes not sufficient. Character Projection (CP) is able to speed up the writing drastically because complex pattern of a limited area can be exposed by one shot [1]. We tested CP in the Vistec SB350 OS for optical applications and found a shot count reduction up to 1/1000, especially for geometries which are hard to approximate by geometrical primitives. Additionally, the resolution and the pattern quality were influenced in a positive way. Another benefit is the possibility to spend a part of the gain in writing speed to the use of a high resolution but low sensitive resist like HSQ. The tradeoff between speed and flexibility should be compensable by a large number of characters available. © 2012 SPIE.


Slodowski M.,Vistec Electronic Beam GmbH | Doring H.-J.,Vistec Electronic Beam GmbH | Stolberg I.A.,Vistec Electronic Beam GmbH | Dorl W.,Vistec Electronic Beam GmbH
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2010

The development of next-generation lithography (NGL) such as EUV, NIL and maskless lithography (ML2) are driven by the half pitch reduction and increasing integration density of integrated circuits down to the 22nm node and beyond. For electron beam direct write (EBDW) several revolutionary pixel based concepts have been under development since several years. By contrast an evolutionary and full package high throughput multi electron-beam approach called Multi Shaped Beam (MSB), which is based on proven Variable Shaped Beam (VSB) technology, will be presented in this paper. In the recent decade VSB has already been applied in EBDW for device learning, early prototyping and low volume fabrication in production environments for both silicon and compound semiconductor applications. Above all the high resolution and the high flexibility due to the avoidance of expensive masks for critical layers made it an attractive solution for advanced technology nodes down to 32nm half pitch. The limitation in throughput of VSB has been mitigated in a major extension of VSB by the qualification of the cell projection (CP) technology concurrently used with VSB. With CP more pixels in complex shapes can be projected in one shot, enabling a remarkable shot count reduction for repetitive pattern. The most advanced step to extend the mature VSB technology for higher throughput is its parallelization in one column applying MEMS based multi deflection arrays. With this Vistec MSB technology, multiple shaped beamlets are generated simultaneously, each controllable individually in shape size and beam on time. Compared to pixel based ML2 approaches the MSB technology enables the maskless, variable and parallel projection of a large number of pixels per beamlet times the number of beamlets. Basic concepts, exposure examples and performance results of each of the described throughput enhancement steps will be presented. © 2010 SPIE.


Galler R.,EQUIcon Software GmbH | Melzer D.,EQUIcon Software GmbH | Boettcher M.,Vistec Electronic Beam GmbH | Krueger M.,EQUIcon Software GmbH | And 2 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2010

All patterning technologies, including e-beam writing, encounter growing challenges to meet the requirements of current and future semiconductor technology nodes. For e-beam writing the electron proximity effect is one of the most prominent influencing factors and its optimal correction is a key for achieving sufficient pattern fidelity. Leading correction algorithms like PROXECCO® currently use a dose modulation strategy for correcting the electron proximity effect. For obtaining minimum feature sizes of below 50 nm and for most demanding patterns like dense line geometries additional correction strategies seem to be necessary to meet the pattern fidelity requirements of the semiconductor industry. The dense line geometries are so sensitive to suboptimal correction because of the achievable contrast in that case, which is minimal. The result is a small process window and an increased line width roughness (LWR). One of the possible modifications of the correction strategy is a combination of dose correction and a variation of the pattern shape. For the scope of this paper we will investigate the potential gains (contrast enhancement) and losses (increase in data prep and writing time) resulting from the so called "geometrically induced dose correction" method available in the current version of PROXECCO® integrated in the ePLACE® software package. ePLACE means eBeam Direct Write and Mask Data Preparation Layout Console and offers the ability to process layout data as well as a state-of-the-art visualization and exposure simulation capabilities. In this paper we show that especially the simulation capability can be used to reduce experimental work significantly. The "geometrically induced dose correction" method is in fact a shape size biasing operation followed by a special dose correction to meet the intended shape edges. By theoretical considerations and by applying the ePLACE® automatic simulation & measurement feature to a huge number of measurement areas we investigate the influence of the geometrically induced dose correction on exposure contrast and CD uniformity for test and real patterns. We also discuss how the geometrically induced dose correction influences the data prep time and finally the e-beam writing time. © 2010 SPIE.


Slodowski M.,Vistec Electronic Beam GmbH | Doering H.-J.,Vistec Electronic Beam GmbH | Dorl W.,Vistec Electronic Beam GmbH | Stolberg I.A.,Vistec Electronic Beam GmbH
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2010

In this paper a full package high throughput multi electron-beam approach, called Multi Shaped Beam (MSB), for applications in mask making as well as direct write will be presented including complex proof-of-lithography results. The basic concept enables a significant exposure shot count reduction for advanced patterns compared to standard Variable Shaped Beam (VSB) systems and allows full pattern flexibility by concurrently using MSB, VSB and Cell Projection (CP). Proof of lithography results will be presented, which have been performed using a fully operational electron-beam lithography system including data path and substrate scanning by x/y-stage movement. © 2010 Copyright SPIE - The International Society for Optical Engineering.


Zeitner U.D.,Friedrich - Schiller University of Jena | Zeitner U.D.,Fraunhofer Institute for Applied Optics and Precision Engineering | Harzendorf T.,Fraunhofer Institute for Applied Optics and Precision Engineering | Fuchs F.,Fraunhofer Institute for Applied Optics and Precision Engineering | And 3 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2014

The fabrication of complex nano-optical structures for plasmonics, photonic-crystals, or meta-materials on application relevant areas by electron-beam lithography requires a highly parallel writing strategy. In case of periodic pattern as they are found in most of the mentioned optical elements this can be achieved by a so called character projection writing principle where complex exposure pattern are coded in a stencil mask and exposed with a single shot. Resulting shotcount and writing time reductions compared to standard Variable-Shaped-Beam exposures can be in the order of 100..10000. The limitation in flexibility by using hard-coded exposure shapes can be overcome by implementing the character projection principle with a highly precise motorized aperture stage capable of carrying several 1000 different apertures. Examples of nano-optical elements fabricated with the new character projection principle are presented. © 2014 SPIE.


Goodyear A.,Oxford Instruments | Boettcher M.,Vistec Electronic Beam GmbH | Stolberg I.,Vistec Electronic Beam GmbH | Cooke M.,Oxford Instruments
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2015

Electron beam writing remains one of the reference pattern generation techniques, and plasma etching continues to underpin pattern transfer. We report a systematic study of the plasma etch resistance of several e-beam resists, both negative and positive as well as classical and Chemically Amplified Resists: HSQ[1,2] (Dow Corning), PMMA[3] (Allresist GmbH), AR-P6200 (Allresist GmbH), ZEP520 (Zeon Corporation), CAN028 (TOK), CAP164 (TOK), and an additional pCAR (non-disclosed provider). Their behaviour under plasma exposure to various nano-scale plasma etch chemistries was examined (SF6/C4F8 ICP silicon etch, CHF3/Ar RIE SiO2 etch, Cl2/O2 RIE and ICP chrome etch, and HBr ICP silicon etch). Samples of each resist type were etched simultaneously to provide a direct comparison of their etch resistance. Resist thicknesses (and hence resist erosion rates) were measured by spectroscopic ellipsometer in order to provide the highest accuracy for the resist comparison. Etch selectivities (substrate:mask etch rate ratio) are given, with recommendations for the optimum resist choice for each type of etch chemistry. Silicon etch profiles are also presented, along with the exposure and etch conditions to obtain the most vertical nano-scale pattern transfer. We identify one resist that gave an unusually high selectivity for chlorinated and brominated etches which could enable pattern transfer below 10nm without an additional hard mask. In this case the resist itself acts as a hard mask. We also highlight the differing effects of fluorine and bromine-based Silicon etch chemistries on resist profile evolution and hence etch fidelity. © 2015 SPIE.


Patent
VISTEC Electronic BEAM GMBH | Date: 2016-06-17

In a particle beam apparatus and a method for operating a particle beam apparatus, the particle beam apparatus has a column having a particle-beam optical system for generating a particle beam, to thereby expose a desired pattern in a vacuum sample chamber in an exposure operation. In a cleaning operation, a regulable gas stream having photodissociatable gas is fed to the column and/or the vacuum sample chamber via a gas-feed system. The photodissociation of the supplied gas is brought about in the cleaning operation with the aid of a plurality of light sources distributed spatially in the column and/or in the vacuum sample chamber. In the cleaning operation, individual light sources are able to be switched on and off selectively with respect to time via a control unit connected to the light sources, in order to clean individual elements in the column and/or in the vacuum sample chamber in targeted fashion.

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