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Jinno, Satoshi; Fujita, Natsuko; Tanuma, Hajime*
Dai-23-Kai AMS Shimpojiumu Hokokushu, p.89 - 92, 2022/12
The measurement of chlorine-36 (
Cl) in AMS, which is important for the dating of saline groundwater, is more difficult than other nuclides due to the isobaric interference by sulfur-36 (S). In general, acceleration voltages of 6 MV or higher are required to separate Cl and S. Therefore, this study aims to develop an ion funnel reaction cell and incorporate it into the low energy side of JAEA-AMS-TONO-5MV to selectively suppress S.
Koike, Fumihiro*; Funaba, Hisamichi*; Goto, Motoshi*; Kato, Daiji*; Kato, Takako*; Morita, Shigeru*; Murakami, Izumi*; Sakaue, Hiroyuki*; Sudo, Shigeru*; Suzuki, Chihiro*; et al.
AIP Conference Proceedings 1545, p.202 - 211, 2013/07
Times Cited Count：4 Percentile：83.55(Physics, Applied)Atomic ionic states and transition properties of elements with atomic numbers Z ranging from 50 to 80 are discussed as these are important to the understanding of plasmas containing such heavy elements. As such, data productions and the current status of theoretical calculations in this field are discussed. Further, recent spectroscopic measurements and respective theoretical analyses for W, Gd, and Nd are provided.
Sasaki, Akira; Sunahara, Atsushi*; Furukawa, Hiroyuki*; Nishihara, Katsunobu*; Fujioka, Shinsuke*; Nishikawa, Takeshi*; Koike, Fumihiro*; Ohashi, Hayato*; Tanuma, Hajime*
Journal of Applied Physics, 107(11), p.113303_1 - 113303_11, 2010/06
Times Cited Count：45 Percentile：82.26(Physics, Applied)Atomic processes in Sn plasmas are investigated for application to extreme-ultraviolet (EUV) light sources used in microlithography. An atomic model of Sn is developed on the basis of calculated atomic data using the Hebrew University Lawrence Livermore Atomic Code (HULLAC). Resonance and satellite lines from singly and multiply excited states of Sn ions are identified. The wavelengths of the 4
-4
+ 4
-4 transitions of Sn
to Sn
are investigated. Results of calculation are compared with those of the charge exchange spectroscopy, measurement of the emission spectrum of the laser produced plasma EUV source, and the opacity measurement of a radiatively heated Sn sample. A reasonable agreement is observed between calculated and experimental EUV emission spectra. The spectral emissivity and opacity of Sn plasmas are calculated using a full collisional radiative (CR) model as a function of electron temperature and ion density.
Sasaki, Akira; Sunahara, Atsushi*; Furukawa, Hiroyuki*; Nishihara, Katsunobu*; Nishikawa, Takeshi*; Koike, Fumihiro*; Tanuma, Hajime*
High Energy Density Physics, 5(3), p.147 - 151, 2009/09
Times Cited Count：11 Percentile：39.85(Physics, Fluids & Plasmas)We study the radiative properties of the EUV source to address conditions to achieve an output power and efficiency required for its application to the next generation microlithography. An atomic model is developed based on the atomic data calculated by Hullac code, which is validated through detailed comparisons with experimental emission and a absorption spectra. The atomic model is improved with respect to the wavelength of the strong emission lines, and the number of satellite channels taken into account. As a result, the radiation hydrodynamics model is shown to successfully reproduce the experiments. We show Sn plasma is more efficient than Xe plasma because of the atomic number dependence of the emission wavelength, and the use of CO
lasers as a pumping source has an advantage to reduce satellite contribution and to have narrower emission spectrum to obtain higher conversion efficiency.
Sasaki, Akira; Sunahara, Atsushi*; Nishihara, Katsunobu*; Nishikawa, Takeshi*; Koike, Fumihiro*; Tanuma, Hajime*
Journal of Physics; Conference Series, 163, p.012107_1 - 012107_4, 2009/06
Times Cited Count：5 Percentile：84.83(Physics, Multidisciplinary)no abstracts in English
Ohashi, Hayato*; Suda, Shintaro*; Tanuma, Hajime*; Fujioka, Shinsuke*; Nishimura, Hiroaki*; Nishihara, Katsunobu*; Kai, Takeshi; Sasaki, Akira; Sakaue, Hiroyuki*; Nakamura, Nobuyuki*; et al.
Journal of Physics; Conference Series, 163, p.012071_1 - 012071_4, 2009/06
Times Cited Count：7 Percentile：89.27(Physics, Multidisciplinary)Extreme ultra-violet (EUV) emission spectra of multiply charged tin ions were measured in the wavelength range of 10-22 nm following charge exchange collisions or the electron impact excitation of tin ions. In charge exchange collisions, we observed both the resonance lines and the emission lines corresponding to the transitions between the excited states. On the other hand, we observed mainly the resonance lines in the electron impact experiments. We can distinguish the resonance lines from other emission lines in the charge exchange spectrum by comparison with the emission lines in the electron impact spectrum.
Suzuki, Chihiro*; Kato, Takako*; Sato, Kuninori*; Tamura, Naoki*; Kato, Daiji*; Sudo, Shigeru*; Yamamoto, Norimasa*; Tanuma, Hajime*; Ohashi, Hayato*; Suda, Shintaro*; et al.
Journal of Physics; Conference Series, 163, p.012019_1 - 012019_4, 2009/06
Times Cited Count：11 Percentile：94.18(Physics, Multidisciplinary)We have measured EUV spectra from highly charged tin ions in low density plasmas produced in the Large Helical Device (LHD). The well known dense spectral structure around 13.5 nm is measured when the plasma is rapidly cooled and approaching radioactive collapse, while the sparse spectrum with several unidentified discrete lines from 13.8-14.6 nm is observed if the plasma is cooled more slowly. The dominant charge states in the former case are Sn
-Sn
. The latter case may be explained by considering the spectral lines from charge states higher than Sn
.
Sasaki, Akira; Sunahara, Atsushi*; Nishihara, Katsunobu*; Nishikawa, Takeshi*; Koike, Fumihiro*; Tanuma, Hajime*
Reza Kenkyu, 36(Suppl.), p.1132 - 1135, 2008/11
no abstracts in English
Nishihara, Katsunobu*; Sunahara, Atsushi*; Sasaki, Akira; Tanuma, Hajime*; Koike, Fumihiro*; Fujioka, Shinsuke*; Nishimura, Hiroaki*; Shimada, Yoshinori*
Reza Kenkyu, 36(11), p.690 - 699, 2008/11
The critical issue for realization of a laser produced plasma (LPP) extreme ultraviolet (EUV) light source is the conversion efficiency (CE) from incident laser power to EUV radiation of 13.5 nm wavelength. From an atomic physics, we show that tin is the most suitable radiation material compared with xenon and lithium. We also show the optimization of laser and target conditions to obtain high CE using a power balance model. We propose a double-pulse irradiation scheme for high CE using a carbon dioxides laser and a droplet target.
Sasaki, Akira; Sunahara, Atsushi*; Nishihara, Katsunobu*; Nishikawa, Takeshi*; Koike, Fumihiro*; Tanuma, Hajime*
Journal of Physics; Conference Series, 112, p.042062_1 - 042062_4, 2008/00
Times Cited Count：5 Percentile：84.16(Physics, Fluids & Plasmas)no abstracts in English
Izawa, Yasukazu*; Nishihara, Katsunobu*; Tanuma, Hajime*; Sasaki, Akira; Murakami, Masakatsu*; Sunahara, Atsushi*; Nishimura, Hiroaki*; Fujioka, Shinsuke*; Aota, Tatsuya*; Shimada, Yoshinori*; et al.
Journal of Physics; Conference Series, 112, p.042047_1 - 042047_4, 2008/00
Times Cited Count：8 Percentile：93.57(Physics, Fluids & Plasmas)In the development of a high power EUV source used in the EUV lithography system, we have been constructed EUV database of laser-produced tin plasma by the theoretical and experimental studies. On the basis of our understanding, the optimum conditions of lasers and plasmas were clarified, and we proposed the guidelines of laser plasma to obtain clean, efficient and high power EUV source for the practical EUV lithography system. In parallel to such studies, novel targets and high power laser system to generate the optimized EUV source plasma have been developed.
Nishihara, Katsunobu*; Sunahara, Atsushi*; Sasaki, Akira; Nunami, Masanori*; Tanuma, Hajime*; Fujioka, Shinsuke*; Shimada, Yoshinori*; Fujima, Kazumi*; Furukawa, Hiroyuki*; Kato, Takako*; et al.
Physics of Plasmas, 15(5), p.056708_1 - 056708_11, 2008/00
Times Cited Count：122 Percentile：97.46(Physics, Fluids & Plasmas)Sunahara, Atsushi*; Sasaki, Akira; Tanuma, Hajime*; Nishihara, Katsunobu*; Nishikawa, Takeshi*; Koike, Fumihiro*; Fujioka, Shinsuke*; Aota, Tatsuya*; Yamaura, Michiteru*; Shimada, Yoshinori*; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 83(11), p.920 - 926, 2007/11
We study the EUV emission from laser produced Sn plasmas using the 1D and 2D radiation hydrodynamics simulation, for the development of EUV source for the next generation semiconductor lithography. The opacity and emissivity of the plasma used in the simulation are calculated by a detailed atomic model, with the accurate wavelength of emission lines obtained from the detailed spectroscopic measurements. Calculation is shown to reproduce the experimental spectrum and conversion efficiency reasonably, including the effect of photo pumping which modifies the EUV emission spectrum in the case with a long scale length of the plasmas.
Tanuma, Hajime*; Sasaki, Akira
Purazuma, Kaku Yugo Gakkai-Shi, 83(8), p.679 - 683, 2007/08
no abstracts in English
Sasaki, Akira; Sunahara, Atsushi*; Nishihara, Katsunobu*; Nishikawa, Takeshi*; Fujima, Kazumi*; Kagawa, Takashi*; Koike, Fumihiro*; Tanuma, Hajime*
High Energy Density Physics, 3(1-2), p.250 - 255, 2007/05
Times Cited Count：17 Percentile：49.63(Physics, Fluids & Plasmas)no abstracts in English
Sasaki, Akira; Nishihara, Katsunobu*; Sunahara, Atsushi*; Nishikawa, Takeshi*; Koike, Fumihiro*; Kagawa, Takashi*; Tanuma, Hajime*
Proceedings of SPIE's International Symposium on Microlithography, Vol.6151, p.61513W_1 - 61513W_8, 2006/03
The atomic processes in the Xe and Sn plasmas are investigated. The wavelength of atomic transitions is shown to have a critical effect in reproducing experiments. The wavelengths of resonance lines in our model are improved through detailed comparison with charge specific spectroscopic measurement. Distribution of satellite lines in the presence of the effect of the configuration interaction (CI) is investigated. The spectral profile of Xe and Sn emission, with determines fraction of usable EUV power, is discussed with respect to its dependence on the plasma temperature, density as well as the optical depth.
Fujima, Kazumi*; Nishihara, Katsunobu*; Kawamura, Toru*; Furukawa, Hiroyuki*; Kagawa, Takashi*; Koike, Fumihiro*; More, R.*; Murakami, Masakatsu*; Nishikawa, Takeshi*; Sasaki, Akira; et al.
Emerging Lithographic Technologies VIII, Proceedings of SPIE Vol.5374, p.405 - 412, 2004/00
no abstracts in English
Sasaki, Akira; Nishihara, Katsunobu*; Sunahara, Atsushi*; Maehara, Hiroaki*; Nishikawa, Takeshi*; Koike, Fumihiro*; Kagawa, Takashi*; Tanuma, Hajime*
no journal, ,
no abstracts in English
Sasaki, Akira; Nishihara, Katsunobu*; Maehara, Hiroaki*; Sunahara, Atsushi*; Nishikawa, Takeshi*; Koike, Fumihiro*; Kagawa, Takashi*; Tanuma, Hajime*
no journal, ,
no abstracts in English
Sasaki, Akira; Nishihara, Katsunobu*; Maehara, Hiroaki*; Sunahara, Atsushi*; Nishikawa, Takeshi*; Koike, Fumihiro*; Kagawa, Takashi*; Tanuma, Hajime*
no journal, ,
no abstracts in English
