The refined EUV mask model

I. A. Makhotkin; M. Wu; V. Soltwisch; F. Scholze; V. Philipsen

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arXiv · 1912.09075

The refined EUV mask model

I. A. Makhotkin·M. Wu·V. Soltwisch·F. Scholze·V. Philipsen

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Abstract

A refined model of an extreme ultraviolet (EUV) mask stack consisting of the Mo/Si multilayer coated by a Ru protective layer and a TaBN/TaBO absorber layer was developed to facilitate accurate simulations of EUV mask performance for high-NA EUV photo-lithography (EUVL) imaging. The model is derived by combined analysis of the measured EUV and X-ray reflectivity of a state-of-the-art mask blank. These two sets of measurements were analyzed using a combined free-form analysis procedure that delivers high-resolution X-ray and EUV optical constant depth profiles based on self-adapted sets of sublayers as thin as 0.25nm providing a more accurate description of the reflectivity than obtained from only EUV reflectivity. 'Free-form analysis' means that the shape of the layer-interfaces in the model is determined experimentally and is not given a priori by the structure model. To reduce the numerical effort for EUV imaging simulations a low-resolution model of the multilayer and absorber stack with sublayer thicknesses larger than 2nm, that fits to only the EUV reflectance, was derived from the high-resolution model. Rigorous high-NA EUVL simulations were done to compare the performance of the new model to our previous work.

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BibTeX RIS

I. A. Makhotkin, M. Wu, V. Soltwisch, F. Scholze, V. Philipsen. 2019-12-19. The refined EUV mask model. https://arxiv.org/abs/1912.09075

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