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Journal of Micro/Nanolithography, MEMS, and MOEMS

Fully model-based methodology for simultaneous correction of extreme ultraviolet mask shadowing and proximity effects
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Paper Abstract

Extreme ultraviolet (EUV) lithography is a promising candidate for high-volume manufacturing at the 22-nm half-pitch node and beyond. EUV projection lithography systems need to rely on reflective optical elements and masks with oblique illumination for image formation. It leads to undesired effects such as pattern shift and horizontal-to-vertical critical dimension bias, which are generally reported as shadowing. Rule-based approaches proposed to compensate for shadowing include changing mask topography, introducing mask defocus, and biasing patterns differently at different slit positions. However, the electromagnetic interaction between the incident light and the mask topography with complicated geometric patterns, such as optical diffraction, not only causes shadowing but also induces proximity effects. This phenomenon cannot be easily taken into account by rule-based corrections and thus imposes a challenge on a partially model-based correction flow, the so-called combination of rule- and model-based corrections. A fully model-based correction flow, which integrates an in-house optical proximity correction algorithm with rigorous three-dimensional mask simulation, is proposed to simultaneously compensate for shadowing and proximity effects. Simulation results for practical circuit layouts indicate that the fully model-based correction flow significantly outperforms the partially model-based one in terms of correction accuracy, while the total run time is slightly increased.

Paper Details

Date Published: 1 January 2011
PDF: 13 pages
J. Micro/Nanolith. MEMS MOEMS 10(1) 013004 doi: 10.1117/1.3533222
Published in: Journal of Micro/Nanolithography, MEMS, and MOEMS Volume 10, Issue 1
Show Author Affiliations
Philip C. W. Ng, National Taiwan Univ. (Taiwan)
Kuen-Yu Tsai, National Taiwan Univ. (Taiwan)
Yen-Min Lee, National Taiwan Univ. (Taiwan)
Fu-Min Wang, National Taiwan Univ. (Taiwan)
Jia-Han Li, National Taiwan Univ. (Taiwan)
Alek C. Chen, ASML Taiwan Ltd. (Taiwan)

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