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Journal of Micro/Nanolithography, MEMS, and MOEMS

Extreme-ultraviolet secondary electron blur at the 22-nm half pitch node
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Paper Abstract

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.

Paper Details

Date Published: 1 July 2011
PDF: 8 pages
J. Micro/Nanolith. MEMS MOEMS 10(3) 033004 doi: 10.1117/1.3607429
Published in: Journal of Micro/Nanolithography, MEMS, and MOEMS Volume 10, Issue 3
Show Author Affiliations
Roel Gronheid, IMEC (Belgium)
Todd R. Younkin, Intel Corp. (Belgium)
Michael J. Leeson, Intel Corp. (United States)
Carlos Fonseca, Tokyo Electron America, Inc. (United States)
Joshua S. Hooge, Tokyo Electron America, Inc. (United States)
Kathleen Nafus, Tokyo Electron Kyushu Ltd. (Japan)
John J. Biafore, KLA-Tencor Texas (United States)
Mark D. Smith, KLA-Tencor Texas (United States)

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