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28 August 2003 Simulation of extreme ultraviolet masks with defective multilayers
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Proceedings Volume 5130, Photomask and Next-Generation Lithography Mask Technology X; (2003)
Event: Photomask and Next Generation Lithography Mask Technology X, 2003, Yokohama, Japan
Because the capabilities for experimental studies are still limited, a predictive simulation of EUV lithography is very important for a better understanding of the technology. One of the most critical issues in EUV lithography modeling is the description of the mask, especially including multilayer defects. A new model for the characterization of defects in the multilayer of an EUV reflective mask is presented. The mask is divided into an absorber part, which defines the features on the mask, and a multilayer part, which determines the reflectivity of the mask without absorber. Since the height of the mask features is large in comparison to the illumination wavelength, the computation of the absorber part is performed by a finite-difference time-domain (FDTD) method. Because of the limited range of illumination angles with a high reflectivity and the limited diffraction efficiency of the multilayer, the computation of the reflectivity of the defective multilayer is performed by the Fresnel-method. The defect topography is taken into account by means of correcting the phase and the angle of incidence. For the complete computation of the reflected light from the EUV mask a coupling of the two methods is realized. Thus, the model can be applied to two and three dimensional defects and masks. The impact of the defects on the mask reflectivity, the near field and the aerial image is analyzed. Typical mask structures, such as 2D-lines and 3D-dots with various defects, are investigated. First comparisons with another simulation model, the MMFE method, are presented.
© (2003) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Peter Evanschitzky, Andreas Erdmann, Maxime Besacier, and Patrick Schiavone "Simulation of extreme ultraviolet masks with defective multilayers", Proc. SPIE 5130, Photomask and Next-Generation Lithography Mask Technology X, (28 August 2003);

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