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Proceedings Paper

Performance and characteristics of the NXE:3400 optical system enabling sub-10nm node lithography (Conference Presentation)
Author(s): Michael Busshardt; Olaf Conradi; Benjamin Kaminski; Peter Kürz; Jörg Tschischgale; Albert Voit; Markus Hauf; Jörg Zimmermann; Erik Loopstra; Tilmann Heil; Mark A. van de Kerkhof; Jelmer Kamminga; Roel Merry; Hans C. Jasper
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Paper Abstract

The optical train is a key sub-system of each lithography scanner. The single patterning resolution limit of a scanner is determined by the characteristics and performance of its imaging system consisting of illumination and projection optics. The most relevant performance parameters of the illumination system are the maximum achievable setting flexibility, off-axis imaging capability (sigma) and pupil fill ratio (PFR). The projection optics key drivers numerical aperture (NA), aberration level, and stray light determine resolution limit and image quality of the scanner. In EUV lithography, optimizing aerial image contrast and image overlay is of particular importance to achieve the required resolution and edge placement performance of the scanner because stochastic effects degrading the initial image as e.g. resist blur and photon shot noise are still comparably strong. In this paper, we present an overview on the new features of the NXE:3400 EUV optical system designed to improve resolution limit, contrast and overlay performance of the NXE:3400 scanner. The illumination system features a novel design based on a large number of switchable facetted mirrors which enables an unprecedented setting flexibility and reduced pupil fill ratio. Furthermore, the off-axis imaging capability of the illuminator has been extended to the full NA which in combination with the reduced PFR improves the single patterning resolution limit of the NXE:3400 by approximately 20% down to 13nm. In addition, by exploiting the increased flexibility of the 3400 illumination system, we demonstrate the ability to further correct for 3D mask effects, and excellent matching to the NXE:3350 system. The projection optics features a NA of 0.33 with significantly reduced aberration level as compared to the precedent 3350 projection optics. In particular, the non-correctable errors impacting scanner overlay, and the wavefront RMS impacting image contrast have been substantially reduced. Keeping the design concept, the improvements have been implemented such that a seamless matching to the 3350 projection optics is guaranteed. Finally, we present NXE:3400 printing results to verify the imaging performance of the NXE:3400 optical system in resist. NXE:3400B wafer prints demonstrate excellent and consistent imaging performance across several systems in line with the discussed improvements of the optical train.

Paper Details

Date Published: 16 October 2017
Proc. SPIE 10450, International Conference on Extreme Ultraviolet Lithography 2017, 104500D (16 October 2017); doi: 10.1117/12.2280545
Show Author Affiliations
Michael Busshardt, Carl Zeiss SMT GmbH (Germany)
Olaf Conradi, Carl Zeiss SMT GmbH (Germany)
Benjamin Kaminski, Carl Zeiss SMT GmbH (Germany)
Peter Kürz, Carl Zeiss SMT GmbH (Germany)
Jörg Tschischgale, Carl Zeiss SMT GmbH (Germany)
Albert Voit, Carl Zeiss SMT GmbH (Germany)
Markus Hauf, Carl Zeiss SMT GmbH (Germany)
Jörg Zimmermann, Carl Zeiss SMT GmbH (Germany)
Erik Loopstra, Carl Zeiss SMT GmbH (Germany)
Tilmann Heil, Carl Zeiss SMT GmbH (Germany)
Mark A. van de Kerkhof, ASML Netherlands B.V. (Netherlands)
Jelmer Kamminga, ASML Netherlands B.V. (Netherlands)
Roel Merry, ASML Netherlands B.V. (Netherlands)
Hans C. Jasper, ASML Netherlands B.V. (Netherlands)

Published in SPIE Proceedings Vol. 10450:
International Conference on Extreme Ultraviolet Lithography 2017
Paolo A. Gargini; Patrick P. Naulleau; Kurt G. Ronse; Toshiro Itani, Editor(s)

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