16 October 2017 Performance and characteristics of the NXE:3400 optical system enabling sub-10nm node lithography (Conference Presentation)
Author Affiliations +
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.
Conference Presentation
© (2017) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
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, and Hans C. Jasper "Performance and characteristics of the NXE:3400 optical system enabling sub-10nm node lithography (Conference Presentation)", Proc. SPIE 10450, International Conference on Extreme Ultraviolet Lithography 2017, 104500D (16 October 2017); doi: 10.1117/12.2280545; https://doi.org/10.1117/12.2280545


EUV lithography scanner for sub-8nm resolution
Proceedings of SPIE (March 15 2015)
On the extensibility of extreme UV lithography
Proceedings of SPIE (April 07 2011)
Comparison between ADT and PPT for 2X DRAM patterning
Proceedings of SPIE (April 07 2011)
The contact hole solutions for future logic technology nodes
Proceedings of SPIE (November 20 2007)

Back to Top