1 July 2007 Rigorous electromagnetic field mask modeling and related lithographic effects in the low k1 and ultrahigh numerical aperture regime
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J. of Micro/Nanolithography, MEMS, and MOEMS, 6(3), 031002 (2007). doi:10.1117/1.2778447
Abstract
As smaller feature sizes and hyper-numerical apertures (>1.0) are approached, rigorous electromagnetic field (EMF) simulation of light diffraction from the mask predicts a more pronounced impact of the mask topography, the optical properties of the mask materials, and the polarization of the incident light on the resulting intensity and the phase of the diffracted light, and on the imaging performance of a lithographic process. This work applies rigorous EMF simulation for the exploration of several aspects of the imaging performance of different binary and 6% attenuated mask stacks at the limits of dry, water immersion, and high index or oil immersion lithography. Several consequences with respect to typical lithographic performance parameters are discussed. The described mask diffraction phenomena have a strong impact on the sensitivity of printed linewidths and process windows with respect to the illumination intensity in the preferred state (IPS) of polarization. Advanced diffraction phenomena are also shown to be important for the lithographic performance of assist features. A new metric, the so-called assist bending efficiency (ABEF), is proposed to quantify the related effects. Modifications of the phase of the diffracted light may result in placement errors and process-window deformations.
Andreas Erdmann, Peter Evanschitzky, "Rigorous electromagnetic field mask modeling and related lithographic effects in the low k1 and ultrahigh numerical aperture regime," Journal of Micro/Nanolithography, MEMS, and MOEMS 6(3), 031002 (1 July 2007). http://dx.doi.org/10.1117/1.2778447
JOURNAL ARTICLE
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KEYWORDS
Photomasks

Diffraction

Polarization

Refractive index

Lithography

Electromagnetism

Binary data

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