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1 July 2011 Extreme-ultraviolet secondary electron blur at the 22-nm half pitch node
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In this paper the Arrhenius behavior of blur upon extreme ultraviolet (EUV) exposure is investigated through variation of the post-exposure bake (PEB) temperature. In this way, thermally activated parameters that contribute to blur (such as acid/base diffusion) can be separated from nonthermally activated parameters (such as secondary electron blur). The experimental results are analyzed in detail using multiwavelength resist modeling based on the continuum approach and through fitting of the EUV data using stochastic resist models. The extracted blur kinetics display perfectly linear Arrhenius behavior, indicating that there is no sign for secondary electron blur at 22-nm half pitch. At the lowest PEB setting the total blur length is ∼4 nm, indicating that secondary electron blur should be well below that. The stochastic resist model gives a best fit to the current data set with parameters that result in a maximum probability of acid generation at 2.4 nm from the photon absorption site. Extrapolation of the model predicts that towards the 16-nm half pitch the impact on sizing dose is minimal and an acceptable exposure latitude is achievable. In order to limit the impact on linewidth roughness at these dimensions it will be required to control acid diffusion to ∼5 nm.
©(2011) Society of Photo-Optical Instrumentation Engineers (SPIE)
Roel Gronheid, Todd R. Younkin, Michael J. Leeson, Carlos Fonseca, Joshua S. Hooge, Kathleen Nafus, John J. Biafore, and Mark D. Smith "Extreme-ultraviolet secondary electron blur at the 22-nm half pitch node," Journal of Micro/Nanolithography, MEMS, and MOEMS 10(3), 033004 (1 July 2011).
Published: 1 July 2011

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