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Proceedings Paper

Acid proliferation to improve the sensitivity of EUV resists: a pulse radiolysis study
Author(s): Kazuyuki Enomoto; Koji Arimitsu; Atsutaro Yoshizawa; Hiroki Yamamoto; Akihiro Oshima; Takahiro Kozawa; Seiichi Tagawa
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Paper Abstract

The yields of acid have been measured in the electron-beam irradiation of triphenylsulfonium triflate (TPS-Tf) and pinanediol monosulfonates, which consist of tosylate (PiTs), 4-fluorobenzenesulfonate (Pi1F), or 4-trifluoromethylbenzenesulfonate (Pi3F), as an acid amplifier blended in 4-hydroxystyrene matrixes. The acid yields efficiency decreases when PiTs is present, while its efficiency increases in the presence of Pi3F. Reactions of the electrons with TPS-Tf and pinanediol monosulfonates have been studied using pulse radiolysis in liquid tetrahydrofuran (THF) to evaluate the kinetic contributions to acid production. The THF-solvated electrons react with PiTs, Pi1F, and Pi3F to produce the corresponding radical anions; the rate constants are estimated to be 4.1, 5.1, and 9.2 × 1010 M-1 s-1, respectively. Electron transfer from PiTs•-, Pi1F•-, and Pi3F•- radical anions to TPS-Tf occurs with the rate constants of 5.7×1010, 1.2×1011, and 6.3 × 1010 M-1 s-1, respectively. The long-lived Pi3F•- efficiently undergoes the electron transfer to TPS-Tf to form the TPS-Tf•-, which subsequently decompose to generate TfOH. On the other hand, the decay channels of PiTs•- and Pi1F•-, which possess a relatively short lifetime, are presumably dependent on its reactions with solvated protons (charge recombination) rather than the electron transfer to TPS-Tf. The novel acid production pathway via the electron transfer from pinanediol monosulfonate radical anions to TPS-Tf is presented.

Paper Details

Date Published: 8 April 2011
PDF: 10 pages
Proc. SPIE 7969, Extreme Ultraviolet (EUV) Lithography II, 79692M (8 April 2011); doi: 10.1117/12.881672
Show Author Affiliations
Kazuyuki Enomoto, Osaka Univ. (Japan)
Koji Arimitsu, Tokyo Univ. of Science (Japan)
Atsutaro Yoshizawa, Tokyo Univ. of Science (Japan)
Hiroki Yamamoto, Osaka Univ. (Japan)
Akihiro Oshima, Osaka Univ. (Japan)
Takahiro Kozawa, Osaka Univ. (Japan)
Seiichi Tagawa, Osaka Univ. (Japan)

Published in SPIE Proceedings Vol. 7969:
Extreme Ultraviolet (EUV) Lithography II
Bruno M. La Fontaine; Patrick P. Naulleau, Editor(s)

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