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Proceedings Paper

Impact of mask absorber on EUV imaging performance
Author(s): Eelco van Setten; Cheuk Wah Man; Rogelio Murillo; Sjoerd Lok; Koen van Ingen Schenau; Kees Feenstra; Christian Wagner
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Paper Abstract

EUVL requires the use of reflective optics including a reflective mask. The reticle blank contains a reflecting multilayer, tuned for 13.5nm actinic light, and an absorber which defines the dark areas. The oblique incidence of light in combination with the small wavelength in comparison to the mask topography causes a number of effects which are unique to EUV, such as an H-V CD offset and an orientation dependent pattern placement error. These so-called shadowing effects can be mitigated by a smart choice of materials and thicknesses in the absorber stack. In this paper we will provide a comparison of the imaging performance of three reticles with different mask absorber stacks exposed on ASML's two alpha demo tools. We will focus on the imaging performance of 32nm L/S through pitch. Not only is the impact of the mask absorber stack on shadowing evaluated, but also on process windows and MEEF. The experimental data is compared to simulations to support the observations and to provide a more in-depth analysis of the impact of the various layers in the mask stack on CDU at wafer level. The results will be used to estimate the impact on CDU performance of the NXE:3x00 for 27 and 22nm node applications, providing guidance for mask manufacturing for HVM process development.

Paper Details

Date Published: 15 May 2010
PDF: 13 pages
Proc. SPIE 7545, 26th European Mask and Lithography Conference, 754503 (15 May 2010); doi: 10.1117/12.864251
Show Author Affiliations
Eelco van Setten, ASML Netherlands B.V. (Netherlands)
Cheuk Wah Man, ASML Netherlands B.V. (Netherlands)
Rogelio Murillo, ASML Netherlands B.V. (Netherlands)
Sjoerd Lok, ASML Netherlands B.V. (Netherlands)
Koen van Ingen Schenau, ASML Netherlands B.V. (Netherlands)
Kees Feenstra, ASML Netherlands B.V. (Netherlands)
Christian Wagner, ASML Netherlands B.V. (Netherlands)

Published in SPIE Proceedings Vol. 7545:
26th European Mask and Lithography Conference
Uwe F.W. Behringer; Wilhelm Maurer, Editor(s)

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