Extreme ultraviolet mask roughness: requirements, characterization, and modeling

Patrick Naulleau; Suchit Bhattaria; Rick Chao; Rene Claus; Kenneth Goldberg; Frank Goodwin; Eric Gullikson; Donggun Lee; Andy Neureuther; Jong-Ju Park

doi:10.1117/12.2070303

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28 July 2014 Extreme ultraviolet mask roughness: requirements, characterization, and modeling

Patrick Naulleau, Suchit Bhattaria, Rick Chao, Rene Claus, Kenneth Goldberg, Frank Goodwin, Eric Gullikson, Donggun Lee, Andy Neureuther, Jong-Ju Park

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Proceedings Volume 9256, Photomask and Next-Generation Lithography Mask Technology XXI; 92560J (2014) https://doi.org/10.1117/12.2070303
Event: Photomask Japan 2014, 2014, Yokohama, Japan

Abstract

It is now well established that extremely ultraviolet (EUV) mask multilayer roughness can lead to wafer-plane line-edge roughness (LER) in lithography tools. It is also evident that this same effect leads to sensor plane variability in inspection tools. This is true for both patterned mask and mask blank inspection. Here we evaluate mask roughness specifications explicitly from the actinic inspection perspective. The mask roughness requirement resulting from this analysis are consistent with previously described requirements based on lithographic LER. In addition to model-based analysis, we also consider the characterization of multilayer mask roughness and evaluate the validity of using atomic force microscopy (AFM) based measurements by direct comparison to EUV scatterometry measurements as well as aerial image measurements on a series of high quality EUV masks. The results demonstrate a significant discrepancy between AFM results and true EUV roughness as measured by actinic scattering.

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Patrick Naulleau, Suchit Bhattaria, Rick Chao, Rene Claus, Kenneth Goldberg, Frank Goodwin, Eric Gullikson, Donggun Lee, Andy Neureuther, and Jong-Ju Park "Extreme ultraviolet mask roughness: requirements, characterization, and modeling ", Proc. SPIE 9256, Photomask and Next-Generation Lithography Mask Technology XXI, 92560J (28 July 2014); https://doi.org/10.1117/12.2070303

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