プラズマ光源関連イオンの EBIT による分光

Transcription

1 プラズマ光源関連イオンの EBIT による分光 Emission spectroscopy of multiply charged ions related to plasma light sources with an EBIT 大橋隼人, 八釼純治, 坂上裕之 *, 中村信行 レーザー新世代研究センター, 電気通信大学 * 核融合科学研究所 2012 年度原子分子データ応用フォーラムセミナー 2012 年 12 月 日核融合科学研究所, 土岐市, 岐阜県

2 Outline Experimental setup Electron beam ion trap (EBIT) EUV spectrometer Motivation & Results and discussion for Sn ions Semiconductor photo-lithography Extreme ultra-violet (EUV) lithography Gd ions Beyond EUV lithography Bi ions Water window, Live cell imaging EBIT emission spectra Comparison with other emissions and Calc. (FAC) Summary and Outlook

3 Principle of an EBIT (Electron Beam Ion Trap) Penning-like ion trap + High density electron beam Successive ionization photon Ion trap Well-type potential (DT1, 2, 3) + Space charge (e-beam) High density electron beam Superconductive magnets Emission spectroscopy Ion extraction; collision expt. 3

4 Two EBITs at UEC Tokyo Tokyo-EBIT since 1995 CoBIT since 2007

5 Tokyo-EBIT e-beam energy e-beam current Magnetic field Cryostat temp. : kev : 330 ma (max) : 4.5 T (max) : 4.2 K (LHe) Ion trap Middle of the trap

6 CoBIT (Compact, Corona, EBIT) N. Nakamura et al., Rev. Sci. Instrum., 79 (2008) LN 2 tank 10 cm High-T c SCM Ion trap e-gun e-beam energy e-beam current Magnetic field Cryostat temp. : kev : 20 ma (max) : 0.2 T (max) : 77 K (LN 2 )

7 The core of CoBIT Extractor Collector DT3 DT2 DT1 Soft iron Trap Extractor Collector Trap region e-gun e-gun High-T c SCM

8 Comparison between two EBITs Tokyo-EBIT CoBIT e-beam energy / kev e-beam current (max) / ma Magnetic field (max) / T 4.5 (typically 4.0) 0.2 (typically < 0.1) Cryostat temp. / K Coolant LHe LN 2 Height / m ~ 4 ~ 0.4

9 Fractional abundance in hot plasmas W q+ T. Pütterich, Ph.D thesis. Running Reactor CoBIT ITER Tokyo-EBIT

10 What we can do using an EBIT? Kr nm IP(15+) : 538 ev IP(16+) : 588 ev IP(17+) : 640 ev Residual gas ions Kr nm N. Nakamura et al., Rev. Sci. Instrum., (2008)

11 EUV spectrometer at the Tokyo-EBIT Trapped ions Slide stage Peltier cooled CCD camera GV Grating Rotatable stage Grating 1 Grating 2 Groove density / lines/mm Curvature radius / m Distance (r) / mm Metallic Sn/Gd/Bi in a Knudsen 1100 o C Distance (r ) / mm Incident angle (α) / degree Wavelength H. Ohashi range et al., / nm Rev. Sci. Instrum (2011) 25

12 EUV spectrometer at the Tokyo-EBIT Back-illuminated CCD Grating chamber Tokyo-EBIT Grating chamber Back-illuminated CCD

13 Sn ions

14 Semiconductor Photo-Lithography Resolution Exposure light wavelength Shorter wavelength Highly integrated The optical layout of the engineering test stand for EUV lithography.

15 Developments of the exposure light wavelength What is next?

16 Reflectivity Extreme Ultra-Violet (EUV) Lithography Exposure light Wavelength E / ev l / m Light Source Optical Mirror Decided! Microwave Infrared Present Near future nm 13.5nm 380nm Ultra-Violet 780nm Visible Wavelength / nm X-ray Reflectivity of Mo/Si multi-layer mirror (MLM) for EUV lithography g-ray l = 13.5 nm ( 91.9 ev ) 3Li, 50 Sn and 54 Xe plasmas

17 Electron beam energy / nm EUV emission spectra of Sn ions Unresolved transition array (UTA) of 4d-4f and 4p-4d transitions near 13.5 nm IPs to produce each charge state / ev 10+ : : : : : : : : : : : : : : Wavelength / nm J. Yatsurugi et al., Phys. Scr., T (2011)

18 Intensity / arb. units Intensity / arb. units Complementary spectroscopy of Sn ions CXS : Sn 15+ -He EBIT : q max = 14 E e ~ 312 ev I e = 2.2 ma Charge exchange collision (CXS) Resonance line Transition between excited states Wavelength / nm CXS : Sn 18+ -He EBIT : electron impact Resonance line EBIT : q max = 17 E e ~ 473 ev I e = 3.3 ma EBIT Charge exchange Complementary Expt Wavelength / nm H. Ohashi et al., J. Phys. Conf. Ser., (2009)

19 Gd ions

20 Extreme Ultra-Violet (EUV) Lithography Exposure light Wavelength E / ev l / m Light Source Optical Mirror Microwave Infrared 1 Present Near future Future nm 13.5nm 6.x nm 10-9 Ultra-Violet X-ray 780nm Visible 380nm Calculated normal incidence reflectance and band width 1, g-ray l = 6.x nm 64Gd and 65 Tb plasmas R. Soufli et al., Appl. Opt., (2008). M. Fernandez-Perea et al., J. Opt. Soc. Am. A, (2007).

21 Next-Generation EUV Lithography at 6.x nm S.S.Churilov et al., Phys.Scr (2009) Atomic data for each charge state is needed to understand and optimize the plasma!! Atomic data accumulation!!

22 Electron beam energy dependence Expt. Calc. with FAC, I e = 5 ma, B = 1.5 T Calc. 4-4 band, S.S.Churilov et al.

23 Intensity / arb. units Identification of observed lines with FAC Gd XXXVI 4s-4p (FAC) E e = 1.51 kev (Expt.) Gd XXXV 4s 2-4s4p E e = 1.44 kev Gd XXXIV 4p-4d E e = 1.35 kev Wavelength / nm

24 Identification of observed lines with FAC Ion Sequence Lower level Upper level Expt.wavelength / nm Calc. / nm Conf. State Conf. State This work Previous FAC Gd 35+ Cu-like 4s 4s 1/2 4p 4p 3/ Gd 34+ Zn-like 4s 2 (4s 2 ) 0 4s4p (4s4p) (15) (15) (3) (20) (10) (2) 6 Gd 33+ Ga-like 4s 2 4p 4p 1/2 4s 2 4d 4d 3/ (20) Under identification for other observed emission lines. 1 J. Reader and G. Luther, Phys. Scr., (1981) 2 G. A. Doschek et al., J. Opt. Soc. Am. B, (1988) 3 J. F. Seely et al., Phys. Rev. A, (1989) 4 C. M. Brown et al., At. Data Nucl. Data Tables, (1994) 5 N. Acquista and J. Reader, J. Opt. Soc. Am. B, (1984) 6 J. Reader and G. Luther, Phys. Rev. Lett., (1980) 7 K. B. Fournier et al., Phys. Rev. A, (1994)

25 Bi ions

26 Water window & X-ray microscopy for live cell imaging In vivo!! Light Source: Synchrotrons or Free Electron Laser (FEL) Too big and not easy to use Table-top (laboratory-scale) broadband emission source

27 LPP spectra of Bi ions Cowan code T. Higashiguchi et al., Appl. Phys. Lett., (2012)

28 Summary EUV emission spectroscopy of 50 Sn, 64 Gd and 83 Bi ions with an EBIT. UTA of 4d-4f and 4p-4d transitions contribute to main emissions for EUV light sources. FAC Calc. for line identification discrepancy between Expt. and Calc. Comparison with other emission spectra in different Expt. Outlook Identification of observed emission lines Lower energy Expt. using CoBIT ( Lower charge states) Charge exchange spectroscopy ( Including transitions between excited states) Terbium( 65 Tb) for BEUVL, Zirconium ( 40 Zr) for water window

29 Thank you for your attention!!