skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Opacity Effect on Extreme Ultraviolet Radiation from Laser-Produced Tin Plasmas

Abstract

Opacity effects on extreme ultraviolet (EUV) emission from laser-produced tin (Sn) plasma have been experimentally investigated. An absorption spectrum of a uniform Sn plasma generated by thermal x rays has been measured in the EUV range (9-19 nm wavelength) for the first time. Experimental results indicate that control of the optical depth of the laser-produced Sn plasma is essential for obtaining high conversion to 13.5 nm-wavelength EUV radiation; 1.8% of the conversion efficiency was attained with the use of 2.2 ns laser pulses.

Authors:
; ; ; ; ; ; ; ; ; ; ; ; ;  [1];  [2]; ; ; ;  [3];  [4]
  1. Institute of Laser Engineering, Osaka University, 2-6 Yamada-Oka, Suita, Osaka 565-0871 (Japan)
  2. Advanced Photon Research Center, Kansai Research Establishment, Japan Atomic Energy Research Institute, 8-1 Umemidai, Kizu, Kyoto 619-0215 (Japan)
  3. Institute for Laser Technology, 2-6 Yamada-Oka, Suita, Osaka 565-0871 (Japan)
  4. Department of Electrical and Electronic Engineering, Okayama University, 1-1 Naka 1-chome, Tsushima, Okayama 700-8350 (Japan)
Publication Date:
OSTI Identifier:
20699656
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review Letters; Journal Volume: 95; Journal Issue: 23; Other Information: DOI: 10.1103/PhysRevLett.95.235004; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; ABSORPTION SPECTRA; EXTREME ULTRAVIOLET RADIATION; ION TEMPERATURE; LASER-PRODUCED PLASMA; LASERS; OPACITY; PLASMA DIAGNOSTICS; PLASMA PRODUCTION; TIN; WAVELENGTHS; X-RAY SPECTRA

Citation Formats

Fujioka, Shinsuke, Nishimura, Hiroaki, Nishihara, Katsunobu, Okuno, Tomoharu, Ueda, Nobuyoshi, Ando, Tsuyoshi, Tao, Yezheng, Shigemori, Keisuke, Nakai, Mitsuo, Nagai, Keiji, Norimatsu, Takayoshi, Miyanaga, Noriaki, Izawa, Yasukazu, Mima, Kunioki, Sasaki, Akira, Sunahara, Atsushi, Shimada, Yoshinori, Hashimoto, Kazuhisa, Yamaura, Michiteru, and Nishikawa, Takeshi. Opacity Effect on Extreme Ultraviolet Radiation from Laser-Produced Tin Plasmas. United States: N. p., 2005. Web. doi:10.1103/PhysRevLett.95.235004.
Fujioka, Shinsuke, Nishimura, Hiroaki, Nishihara, Katsunobu, Okuno, Tomoharu, Ueda, Nobuyoshi, Ando, Tsuyoshi, Tao, Yezheng, Shigemori, Keisuke, Nakai, Mitsuo, Nagai, Keiji, Norimatsu, Takayoshi, Miyanaga, Noriaki, Izawa, Yasukazu, Mima, Kunioki, Sasaki, Akira, Sunahara, Atsushi, Shimada, Yoshinori, Hashimoto, Kazuhisa, Yamaura, Michiteru, & Nishikawa, Takeshi. Opacity Effect on Extreme Ultraviolet Radiation from Laser-Produced Tin Plasmas. United States. doi:10.1103/PhysRevLett.95.235004.
Fujioka, Shinsuke, Nishimura, Hiroaki, Nishihara, Katsunobu, Okuno, Tomoharu, Ueda, Nobuyoshi, Ando, Tsuyoshi, Tao, Yezheng, Shigemori, Keisuke, Nakai, Mitsuo, Nagai, Keiji, Norimatsu, Takayoshi, Miyanaga, Noriaki, Izawa, Yasukazu, Mima, Kunioki, Sasaki, Akira, Sunahara, Atsushi, Shimada, Yoshinori, Hashimoto, Kazuhisa, Yamaura, Michiteru, and Nishikawa, Takeshi. Fri . "Opacity Effect on Extreme Ultraviolet Radiation from Laser-Produced Tin Plasmas". United States. doi:10.1103/PhysRevLett.95.235004.
@article{osti_20699656,
title = {Opacity Effect on Extreme Ultraviolet Radiation from Laser-Produced Tin Plasmas},
author = {Fujioka, Shinsuke and Nishimura, Hiroaki and Nishihara, Katsunobu and Okuno, Tomoharu and Ueda, Nobuyoshi and Ando, Tsuyoshi and Tao, Yezheng and Shigemori, Keisuke and Nakai, Mitsuo and Nagai, Keiji and Norimatsu, Takayoshi and Miyanaga, Noriaki and Izawa, Yasukazu and Mima, Kunioki and Sasaki, Akira and Sunahara, Atsushi and Shimada, Yoshinori and Hashimoto, Kazuhisa and Yamaura, Michiteru and Nishikawa, Takeshi},
abstractNote = {Opacity effects on extreme ultraviolet (EUV) emission from laser-produced tin (Sn) plasma have been experimentally investigated. An absorption spectrum of a uniform Sn plasma generated by thermal x rays has been measured in the EUV range (9-19 nm wavelength) for the first time. Experimental results indicate that control of the optical depth of the laser-produced Sn plasma is essential for obtaining high conversion to 13.5 nm-wavelength EUV radiation; 1.8% of the conversion efficiency was attained with the use of 2.2 ns laser pulses.},
doi = {10.1103/PhysRevLett.95.235004},
journal = {Physical Review Letters},
number = 23,
volume = 95,
place = {United States},
year = {Fri Dec 02 00:00:00 EST 2005},
month = {Fri Dec 02 00:00:00 EST 2005}
}
  • The direct comparison of the emission characteristics of an extreme ultraviolet (EUV) light between the CO{sub 2} and the Nd:YAG laser-produced plasmas (LPP) with a solid tin target is reported. In the case of the Nd:YAG LPP, the conversion efficiency (C.E.) peaked at a laser intensity of about 5x10{sup 10} W/cm{sup 2} and decreased at higher laser intensity. In the case of the CO{sub 2} LPP, the C.E. monotonically increased up to 2x10{sup 10} W/cm{sup 2}, where the C.E. is comparable to the maximum C.E. of the Nd:YAG LPP. The spectral efficiency of the Nd:YAG LPP within the 2% bandwidthmore » around 13.5 nm decreased with laser intensity. The corresponding spectral efficiency of the CO{sub 2} LPP was almost constant. This observation indicates the potential of the CO{sub 2} laser-produced LPP as the EUV light source for the EUV lithographic systems.« less
  • Out-of-band (OOB) radiation (at wavelengths longer than 130 nm) from an extreme ultraviolet (EUV) light source reduces the precision of lithography. The energy of the OOB radiation from laser-produced Sn plasmas were measured by using an absolutely calibrated transmission grating spectrometer equipped with a charge-coupled device. The dependence of the OOB radiant energy on the mass and size of the tin fuel was clarified. The dominant source of the OOB radiation is peripheral heating around the laser spot via electron thermal conduction and radiation from the high-temperature EUV emission region.
  • Conversion efficiencies (CEs) from incident laser energy to 13.5 nm light within a 2% bandwidth were measured with changing laser pulse durations for laser-produced tin plasmas. Experimental results indicate that the optimum pulse duration is determined by two parameters: one is the optical depth of tin plasma for 13.5 nm light and the other is laser absorption rate in 13.5 nm emission-dominant region. The maximum CE of 2.2% is obtained with pulse duration of 2.3 ns.
  • Properties of ion debris emitted from laser-produced mass-limited tin plasmas have been experimentally investigated for an application to extreme ultraviolet (EUV) lithography. Simple scaling laws to design the mass-limited target, which is a key technique to minimize contamination of the first EUV collection mirror, is discussed. The measured energy spectrum of the tin ions is consistent with a prediction by the isothermal expansion model. The average charge state of the tin ions is evaluated to be +5 at 180 mm away from the plasma, and higher-energy ions have higher charge state. It was found that not only EUV emission butmore » also ion energy spectra are sensitively affected by the target mass limitation.« less
  • Influence of initial density of tin (Sn) targets has been quantitatively investigated for efficient extreme ultraviolet light emission from laser-produced plasmas. With a decrease in the initial density, conversion efficiency (CE) from incident laser energy to output 13.5 nm light energy in a 2% bandwidth increases; 2.2% of the peak CE was attained with use of 7% low-density SnO{sub 2} targets (0.49 g/cm{sup 3}) irradiated with a Nd:YAG laser, of which wavelength, pulse duration, and intensity are, respectively, 1.064 {mu}m, 10 ns, and 5x10{sup 10} W/cm{sup 2}. The peak CE is 1.7 times higher than that obtained with the usemore » of solid density Sn targets. Experimental results may be attributed to the influence of the initial density and/or microstructure of the targets on expansion dynamics of the plasmas.« less