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Stuttgart, Germany

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.


Heidler N.,Fraunhofer Institute for Applied Optics and Precision Engineering | Heidler N.,Friedrich - Schiller University of Jena | Schenk C.,Fraunhofer Institute for Applied Optics and Precision Engineering | Harnisch G.,Fraunhofer Institute for Applied Optics and Precision Engineering | And 5 more authors.
Precision Engineering | Year: 2012

Using linear gas bearing guides in a high vacuum environment, the common method to keep the vacuum quality is to exhaust the gas emitted by the bearing pads before leaking into the vacuum chamber. Thereby the exhaust tubes between the guide and the exhaust pumps should interfere with the guide as little as possible while maintaining a flexible connection and a highly effective exhaustion rate. A novel exhaust system that implements these requirements is described within this paper. The major achievement was the realization of two exhaust tubes slidable into one another combined with the known method of non-contact clearance seals, thus enabling an highly efficient and yet disturbance free exhaustion. This setup was developed and characterized at static and dynamic conditions. An analytical model for dimensioning the non-contact seal was worked out and experimentally verified. The number of seal stages and the clearance height were identified as the major impact factors on the leakage rate of the setup. It is concluded that the investigated approach is very suitable for vacuum compatible gas bearing guides since a vacuum level in the order of 10 -4 Pa was maintained during the experiments. © 2011 Elsevier Inc. All Rights Reserved. All rights reserved.


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.


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.

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