1 January 2006 Estimating resist parameters in optical lithography using the extended Nijboer-Zernike theory
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This study presents an experimental method to determine the resist parameters at the origin of a general blurring of a projected aerial image. The resist model includes the effects of diffusion in the horizontal plane and image blur that originates from a stochastic variation of the focus parameter. We restrict ourselves to the important case of linear models, where the effects of resist processing and focus noise are described by a convolution operation. These types of models are also known as diffused aerial image models. The used mathematical framework is the so-called extended Nijboer-Zernike (ENZ) theory, which allows us to obtain analytical results. The experimental procedure to extract the model parameters is demonstrated for several 193-nm resists under various conditions of postexposure baking temperatures and baking times. The advantage of our approach is a clear separation between the optical parameters, such as feature size, projection lens aberrations, and the illuminator setting on one hand, and process parameters introducing blur on the other.
Peter Dirksen, Joseph J. M. Braat, Augustus J.E.M. Janssen, "Estimating resist parameters in optical lithography using the extended Nijboer-Zernike theory," Journal of Micro/Nanolithography, MEMS, and MOEMS 5(1), 013005 (1 January 2006). https://doi.org/10.1117/1.2168449

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