Gd plasma source modeling at 6.7 nm for future lithography

Journal Article · Mon Dec 05 00:00:00 EST 2011 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.3666042· OSTI ID:22027829

Bowen, Li; Dunne, Padraig; O'Sullivan, Gerry ^[1]; Higashiguchi, Takeshi; Yugami, Noboru ^[2]; Otsuka, Takamitsu ^[2]; Jiang, Weihua ^[3]; Endo, Akira ^[4]

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1. School of Physics, University College Dublin, Belfield, Dublin 4 (Ireland)
2. Department of Advanced Interdisciplinary Sciences, Center for Optical Research and Education (CORE), and Optical Technology Innovation Center (OpTIC), Utsunomiya University, Yoto 7-1-2, Utsunomiya, Tochigi 321-8585 (Japan)
3. Department of Electrical Engineering, Nagaoka University of Technology, Kami-tomiokamachi 1603-1, Nagaoka, Niigata 940-2188 (Japan)
4. Research Institute of Science and Engineering, Waseda University, 3-4-1, Okubo, Shinjuku-ku, Tokyo 169-0072 (Japan)

Plasmas containing gadolinium have been proposed as sources for next generation lithography at 6.x nm. To determine the optimum plasma conditions, atomic structure calculations have been performed for Gd{sup 11+} to Gd{sup 27+} ions which showed that n = 4 - n = 4 resonance transitions overlap in the 6.5-7.0 nm region. Plasma modeling calculations, assuming collisional-radiative equilibrium, predict that the optimum temperature for an optically thin plasma is close to 110 eV and that maximum intensity occurs at 6.76 nm under these conditions. The close agreement between simulated and experimental spectra from laser and discharge produced plasmas indicates the validity of our approach.

• OSTI ID: 22027829
• Journal Information: Applied Physics Letters, Vol. 99, Issue 23; Other Information: (c) 2011 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
COMPUTERIZED SIMULATION
ELECTRIC DISCHARGES
ELECTRON COLLISIONS
ELECTRON TEMPERATURE
EV RANGE
GADOLINIUM
GADOLINIUM IONS
ION TEMPERATURE
LASER RADIATION
LASER-PRODUCED PLASMA
MULTICHARGED IONS
OPTICALLY THIN PLASMA
PLASMA PRODUCTION
PLASMA SIMULATION