Stochastic exposure kinetics of EUV photoresists: a simulation study

Chris A. Mack; James W. Thackeray; John J. Biafore; Mark D. Smith

doi:10.1117/12.881066

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7 April 2011 Stochastic exposure kinetics of EUV photoresists: a simulation study

Chris A. Mack, James W. Thackeray, John J. Biafore, Mark D. Smith

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Proceedings Volume 7969, Extreme Ultraviolet (EUV) Lithography II; 796919 (2011) https://doi.org/10.1117/12.881066
Event: SPIE Advanced Lithography, 2011, San Jose, California, United States

Abstract

BACKGROUND: The stochastic nature of extreme ultraviolet (EUV) resist exposure leads to variations in the resulting acid concentration, which leads to line-edge roughness (LER) of the resulting features. METHODS: Using a stochastic resist simulator, we predicted the mean and standard deviation of the acid concentration for an open-frame exposure and fit the results to analytical expressions. RESULTS: The EUV resist exposure mechanism of the PROLTIH Stochastic Resist Simulator is first order, and an analytical expression for the exposure rate constant C allows prediction of the mean acid concentration of an open-frame exposure to about 1% accuracy over a wide range of parameter values. A second analytical expression for the standard deviation of the acid concentration also matched the output of PROLITH to within about 1%. CONCLUSIONS: Predicting the stochastic uncertainty in acid concentration for EUV resists allows optimization of resist processing and formulations, and may form the basis of a comprehensive LER model.

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Chris A. Mack, James W. Thackeray, John J. Biafore, and Mark D. Smith "Stochastic exposure kinetics of EUV photoresists: a simulation study", Proc. SPIE 7969, Extreme Ultraviolet (EUV) Lithography II, 796919 (7 April 2011); https://doi.org/10.1117/12.881066

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