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Proceedings Paper

Vectorial effects in subwavelength mask imaging
Author(s): Wen-Hao Cheng; Jeff Farnsworth; Theodore M. Bloomstein; Andrew Grenville
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Paper Abstract

Ultra high numerical aperture (NA) enables extension of ArF lithography for the 45 technology node and beyond. The resulting changes in design rules drives feature sizes on the mask into the sub-wavelength regime. As 2-beam imaging techniques (off-axis illumination and alternating phase shift mask) are required for strong resolution enhancement in low-k1 lithography, traditional scalar and paraxial approximations used for optical image modeling are no longer valid in the ultra high NA regime. Vector and thick-mask based models are required to account for topographic effects and large angles of incident light at the reticle plane in ultra-high NA systems. Although vector-based imaging theory is well understood, experimental validation is required to ensure the appropriate topographical and optical parameters are being used. To address these issues, finite-difference time-domain rigorous electromagnetic simulation are compared to experimental measurements of the polarization dependent diffraction efficiencies on advanced optical reticles. Based on these results, the impact of mask induced polarization to vectorial imaging latitude is assessed. The impact of polarization purity, mask absorber profile, and Fresnel effects through the pellicle on process window and OPC are also discussed.

Paper Details

Date Published: 4 November 2005
PDF: 11 pages
Proc. SPIE 5992, 25th Annual BACUS Symposium on Photomask Technology, 599218 (4 November 2005); doi: 10.1117/12.632372
Show Author Affiliations
Wen-Hao Cheng, Intel Corp. (United States)
Jeff Farnsworth, Intel Corp. (United States)
Theodore M. Bloomstein, MIT Lincoln Lab. (United States)
Andrew Grenville, Intel Corp. (United States)
SEMATECH (United States)

Published in SPIE Proceedings Vol. 5992:
25th Annual BACUS Symposium on Photomask Technology
J. Tracy Weed; Patrick M. Martin, Editor(s)

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