EUV & Soft-X X Radiation Plasma Sources

Transcription

1 Properties of High-Intensity EUV & Soft-X X Radiation Plasma Sources Sergey V. Zakharov +, Vasily S. Zakharov 3, Peter Choi EPPRA sas, Villebon sur Yvette, France NRC Kurchatov Institute, Moscow, Russia 3 KIAM RAS, Moscow, Russia + also with UCD, Dublin, Ireland and JIHT RAS, SRC TRINITI, Moscow, Russia

2 Sources for EUV Lithography Diffraction restricts the resolution r λ k NA λ 3.5nm 6.Xnm (hν=9ev 85eV) δλ/λ % NOW EUV for HVM beyond 6 nm The optics is made of multi-layer layer mirrors with reflection efficiency ~7% For HVM: >> W of in-band power at IF within < 3mm sr etendue For mask inspections ABI AIMS APMI : 3 > W/mm sr Sn, Xe High Energy Density plasma (T e =-4eV) radiates in EUV range LPP & DPP

3 EUV Brightness Limit for EUV Source Spherical model of tin plasma EUV source L.(W/mm sr) τ(ns) f(khz) EUV Radiance, MW/mm sr tin Z* Scan R=.4mm R=.8mm R=.6mm R=.3mm R=.65mm R=.5mm R=.5mm R=5mm Detailed spectra from tin plasma with radius R= μm and n e = 9 cm -3 RMHD scan for tin plasma optimized by radius, temperature and density [AL] The radiation selfabsorption limits the in-band EUV radiance from the plasma, and the etendue constraint limits the usable power at IF of a conventional single unit EUV source Spectral Efficiency (Peuv/Prad) Effective Depth (rho*r), g/cm3 g 5 tin Effective Depth (rho*r), g/cm5 R=.4mm R=.8mm R=.6mm R=.3mm R=.65mm R=.5mm R=.5mm R=5mm 3

4 EUV Brightness Limit at Higher Temperature The intensity upper Planckian limit of a single spherical optically thick plasma source in Δλ/λ=% band around λ=3.5nm I e LTE hc Δλ / λ 7 = ( MW / mm sr) 4 hc 9 λ λt T ( ev ) Source with pulse duration τ and repetition rate f yields the timeaverage radiance L =I (τ f) The spectral efficiency has the maximum at T ev L.(W/mm sr) τ(ns) f(khz) For instance, at τ =ns L = (W/mm sr)/khz.. e tin Tin line emission spectra 5 ev ev 5 ev ev 5 ev 3 ev Non-LTE Tin line emission spectra ev 3 ev 4 ev 5 ev 6 ev

5 Combined Nd:YAG - CO Laser System Collector Mirror Target Chamber sub-ns Nd:YAG laser (pre-pulse) Beam splitter EUV / 3.5nm ns-order CO laser (main pulse) Sn Droplet Target 5

6 LPP EUV Source under CO - laser or combined pulse Frame 4 Oct ZSTAR - code output, cell values Frame 5 Oct ZSTAR - code output, cell values Z(cm).5..5 t=.586e+ ns R(cm) Tin plasma density at EUV maximum Frame 4 Oct ZSTAR - code output, cell values DENS(g/ccm) 5.E-3 3.7E-3.7E-3.E-3.5E-3.E-3 8.E-4 6.E-4 4.5E-4 3.4E-4.5E-4.8E-4.4E-4.E-4 7.5E-5 5.5E-5 4.E-5 3.E-5.E-5.7E-5.E-5 9.E-6 6.8E-6 5.E-6 Z(cm).5..5 Time-Integrated Time-integrated EUV source image Frame 4 Oct ZSTAR - code output, cell values Qeuv(J/ccm) 3.E+4.83E+4.65E+4.48E+4.3E+4.3E+4.96E+4.78E+4.6E+4.43E+4.6E+4.9E+4 9.3E E E+3 3.9E+3.7E E+ -.3E+3-3.4E+3 critical-layer -4.78E+3-6.5E+3 instability -8.6E+3 -.E R(cm) Power, MW in-band EUV emission CO -laser. J/pulse w/o prepulse Time, ns in-band EUV emission Z(cm).5..5 t=.9548e+ ns R(cm) DENS(g/ccm).E-3 8.4E-4 7.E-4 6.E-4 5.E-4 4.3E-4 3.6E-4 3.E-4.6E-4.E-4.8E-4.5E-4.3E-4.E-4 9.E-5 7.8E-5 6.6E-5 5.5E-5 4.7E-5 3.9E-5 3.3E-5.8E-5.4E-5.E-5 Z(cm).5..5 Time-Integrated Qeuv(J/ccm).E+4.5E+4.E E+3 9.7E E+3 8.E E+3 7.5E E+3 6.9E+3 5.7E+3 5.E E+3 4.6E E+3 3.3E+3.8E+3.34E+3.86E+3.37E E+ 4.E+ -7.E R(cm) The maximum EUV brightness is up to5 W/mm sr khz Power, MW CO -laser. J/pulse with ps NdYAG prepulse Time, ns 6

7 Conversion Efficiency of CO -laser on pulse duration, with & w/out pre-pulses Main pulse: CO -laser.-.8 J/pulse,,5,3,5ns fwhm, μm focal spot Pre-pulse laser (if applied): Nd:YAG 5 mj -ns pulse, 4μm spot size or Nd:YAG 6 mj - ps pulse, 4μm spot size Target: Liquid tin droplet of 4μm diameter or μm for mj (EUVA) Conditions: different focal positions; different time delay between pre- & main-pulse CE depends strongly on laser intensity and target irradiation conditions Conversion Efficiency, % mj w/out prepulse mj with 6mJ ps prepulse mj with 5mJ ns prepulse mj w/o and with ns prepulse(euva) mj with 6mJ ps prepulse 4mJ with 6mJ ps prepulse 8mJ with 6mJ ps prepulse Pulse duration, ns CE maximum of 3% can be reached at laser energy (mj) in a combined ps-ns pulse 7

8 Laser Assisted Vacuum Arc (LAVA-lamp) A C Discharge capacitance inductance voltages energies current.4 μf 9 nh 3 6 kv.8 7. J ka at 4.5 kv Laser High-current discharge between two rotating electrodes covered with a thin liquid Tin or Galinstan film is triggered by local laser ablation of electrode material. Trigger laser: wavelength 64 nm beam diameter 3 mm focal lens 3 cm energy 5 5 mj (varied by means of rotatable half-wave plate and polarizing beam splitter) Details are presented in the posters : S6 V.S. Zakharov, Larissa Jushkin, S.V. Zakharov et al S3 Isaac Tobin, Larissa Juschkin, Vasily S. Zakharov et al 8

9 Comparison of measured and Z* modelling discharge current and in-band EUV emission tin 9

10 Capillary Discharge EUV Source EXPERIMENT: discharge glow & EUV emission optical streak photograph EUV emission.35 t Photodiode signal (V) kV 3.kV.7kV.5V.8kV 9.5kV.5 Irrandiance E7 ph/cm/s Time (ns) Irradiance Linear Fit of Data_phcms Stored energy (mj) o Wavelength (nm) EUV spectrum o.4 o.3 o. pressure (mbar) Intensity (arb. units)

11 High Brightness EUV Plasma Source pulsed capillary discharge Power source Charge energy Current Pulse Capillary dimension:..5 J 5 - ka ~- ns.6 mm L = -8 mm Energy storage capacitor bank Experimental set up capillary EUV Various electrode geometries Gas:.- Torr gradient He; Xe, N, Ar, Kr,, admixtures (for narrow-band radiation source) Example of simulated geometry Capillary discharge dynamics & emission features: E-beam, plasma channelling (ε>>) Volumetric MHD compression (skin depth >>plasma diameter) Highly ionized ions (fast electrons)

12 Hollow-cathode Capillary Discharge modelling: triggering by fast electrons together with Markov M.B. et al, KIAM RAS Anode Electron beam in the HC capillary discharge capillary capillary run-away electrons electric field drops deeper into HC e-beam concentration (ɛ >>) e-beam-gas ionization Hollow cathode ionization wave In the first few nanoseconds, run-away electrons from the hollow cathode generate a tight ionized channel (< μm diameter) in the gas

13 Capillary Discharge EUV Source Z*-code modelling: resistive regime discharge current, ka Inductive regime I, ka 9kV charge. nf capacitor time, ns Nitrogen as buffer gas Discharge current, ka Resistive regime 3kV charge.9 nf capacitor Time, ns In the resistive regime of capillary discharge, the high joule dissipation in the tight conductive channel produced by hollow cathode electron beam creates an efficient mechanism of plasma heating and EUV or soft X-ray emission. Also, fast electrons increase the ionization degree of heavy ion (Xe, ) plasma increasing eo ipso EUV yield. 3

14 Z(cm) Capillary Discharge EUV Source dynamics & EUV emission 3D volumetric compression Frame Oct ZSTAR - code output, cel t= 3.34E+ ns.4 Anode Ne(Av) capillary capillary Cathode.5 R(cm).E-7 8.E-8 6.7E-8 5.5E-8 4.5E-8 3.7E-8 3.E-8.5E-8.E-8.6E-8.4E-8.E-8 9.E-9 7.4E-9 6.E-9 5.E-9 4.E-9 3.3E-9.7E-9.E-9.8E-9.5E-9.E-9.E-9 Power, MW The traced along the axis, EUV intensity at 3.5nm wavelength 5.3 W/eV mm sr per khz N e =-3 7 cm -3, T e =5-4eV. EUV emission in 3.5nm 496mJ stored energy Time, ns Calculated inband EUV emission.885 W/kHz Frame 3 Oct ZSTAR - code output, cel Z(cm).4 Anode Qeuv(J/ccm) Time-integrated capillary capillary Cathode.5 R(cm).E+ 9.7E- 9.4E- 9.E- 8.8E- 8.5E- 8.E- 7.9E- 7.6E- 7.3E- 7.E- 6.7E- 6.3E- 6.E- 5.7E- 5.4E- 5.E- 4.8E- 4.5E- 4.E- 3.9E- 3.6E- 3.3E- 3.E- EUV source cross-section 4

15 Capillary Discharge EUV Source Z*-code modelling: source optimization In-band EUV energy per shot, uj μJ/shot 496mJ stored energy Pressure, a.u. EUV source scan by stored electrical energy In-band EUV energy per shot, uj Optimization by gas mixture pressure Energy scan calculated (in % band) Resistive regime Stored energy, mj 5

16 EUV Emission of Highly Charged Xe Ions - from plasma with fast electrons Xe XI Xe XXIII 3%@6keV Xe XXIII 5%@6keV Xe XXIII 3%@keV Xe XXIII 5%@keV T e =3eV..8.6 Xe 33 ev Xe 8eV + % 3keV Xe 8eV + % 3keV Xe 8eV + % 3keV Xe 8eV + % 3keV % T e =8eV To produce the maximum EUV light power the double condition is required: + fast electrons have the energy of few kev to produce the highly charged ions + plasma has the temperature sufficient for the excitation of required transitions 6

17 EUV Emission of Highly Charged Xe Ions - from e-beam triggered discharge plasma r). EUV Measurement Capillary discharge. VUV spectrograph data in Wavelength (nm) o. o. o o.4 pressure (mbar) Intensity (arb. units) Bright EUV emission in % band at 3.5 nm can be achieved from highly charged xenon ions in plasma with small percentage of fast electrons 7

18 Focusing Effect Observation 3 ωe n = f( ω ) ω 75cm Source δn = -n <<; δn ~..5 (in solid matter) and δn =.. (in plasma) for EUV range How it is possible in geometrical optics? Know - How EUV band(zr filter)axuv signal(mv) radial distance (mm) Scanned signal profile Data: 3 mm Model: Lorentz Chi^/DoF = 366. R^ =.99 y -8.4 ±7.95 xc -.5 ±. w.93 ±.8 A 67.4 ±34.59 EUV band (Zr filter) radiation beam profile at 3mm from collimator exit radial distance (mm) 4 3 HWHM angle = tan - (.8/4) =.6 degree solid angle = 6.36 e-5 steradian measured half width Linear fit of Data axial distance from end of collimator (mm) 8

19 Wave-guiding Refractive Structure rk θ δn α d dl Δθ r n ( ) N r d dl θ δn sin( α ) r r = n ( ) = refractions are required light trajectory equation Refractive Structure: e-beam exited Kielwasser-waves, k r D - Focussing : Trajectories Trajectories zk θ ( z) dr/dz θ.5 + k δn r ( n ) dz kr.5 δ k zk z tg(angle) tg(angle) analytical numerical 9

20 Multiplexer 4 : - spatial multiplexing Z= Cross Over 5 mm 4 sources operating individually with common power control Z= 7 mm Z= 5 mm All 4 sources aligned to a point without use of any solid optical collector

21 Multiplexer 4 : Optical Schematic static combination of source beams to one Etendue of a single source is E S α π 4 IN FAR-FIELD the etendue of 4 equivalent sources is π E 4FF 4S (α+β) 6 E 4 IN NEAR-FIELD the declination due to β can be corrected and the etendue of 4 equivalent sources is π E 4NF 4S 4 α 4 E α α β S+S (source image) α α α α Source S EUV α+β Facet mirror α Source S

22 Multiplexer 4 : - 4-beams flatness optimization Overlapping of 4 suitably appertured Gaussian beam at a given flatness of % or.% Frame 9 Aug Z-ray - code output, cell values An efficiency with flatness of.% is of % y(sig) a=.8e+ s=.394e x(sig) f.998 Frame 9 Aug Z-ray - code output, cell values % y(sig) a=.8e+ s=.394e+.% x(sig) f

23 Gadolinium Plasma Emitting at 6.x nm Ion populations N e = 9 cm -3 N e =5x cm -3 Relative portion ev 6 ev 7 ev 8 ev 9 ev ev ev ev 3 ev 4 ev 5 ev ev 6 ev 7 ev 8 ev 9 ev ev ev ev 3 ev 4 ev 5 ev e-5 e-5 e-6 e-6 e Ion charge e Ion charge Ion distribution spreads and average charge drops as density increases for LPP very high temperature may be necessary 3

24 Gadolinium Emission low temperature regime.8 Intensity, a.u.7 Line emission spectra Te=6 ev Ne=9 cm-3 Ne=9 cm-3, 5x cm Gd+ - Gd8+ are taken into account Ne=5x cm-3.6 Almost million transitions in total Intensity, a.u.4 More intensive emission is from 4f-4d transitions (4d94f m 4d4fm-)

25 Intensity, MW/eV x cm x sr Efficiency in Non-equilibrium Gd Plasma low temperature regime Spectral modeling Optimized optical throughput Detailed calculations with absorption 4 micron spherical Gd target N e = 9 cm -3, T e =5 ev 6.68 nm of.6% bandwidth 6.3% 6.68 nm of % bandwidth 7.5% N e = 9 cm -3, T e =6 ev 6.68 nm of.6% bandwidth 5.3% 6.68 nm of % bandwidth 8.5% N e =5x cm -3, T e =6 ev 6.68 nm of.6% bandwidth 5.9% 6.68 nm of % bandwidth 6.8% Wavelength, nm 5

26 ZETA Z * RMHD Code Z * BME Z + multi-physics model TABLES nonlte atomic & spectral data (Te,ρ,U) Spectral postprocessing RMHD ( D, 3D ) with: spectral multigroup radiation transport in nonlte; nonstationary, nonlte ionization; sublimation condensation; energy supply (electric power, laser) etc Discharge plasma simulation in real geometry Laser plasma Data output: r,z,v,t e,i,ρ,e,b,z,u ω, etc; visualization EMHD or 3D PIC with: ionization of weekly ionized plasma, discharge triggering Heat flux postprocessing 6

27 Z * Black-box Modeling Engine Black-box Modelling Engine (Z*BME) is integrated into a specific computation environment to provide a turn-key simulation instrument, which does not require knowledge of numerical computation. It has been adapted to simulate DPP and LPP radiation sources in a realistic geometry. Z*BME has been installed: in EUVA, Japan in University College Dublin, Ireland in Czech Technology University, Prague A number of joint simulations of EUV radiation sources with Z* -code of Cymer, Bochum University, Xtreme Tech, FOM, EUVA, UCD, Bruker has been performed in frameworks of collaborations and FACADIX, MoreMoore, Medea+, FIRE projects 7

28 Next Generation Modelling Tools knowledge transfer in FP7 IAPP project FIRE - European FP7 Industry-Academia Partnerships and Pathways project The FIRE project aims to substantially redevelop the Z* code to Z + to include improved atomic physics models and full 3-D plasma simulation of plasma dynamics spectral radiation transport non-equilibrium atomic kinetics with fast electrons transport of fast ions/electrons condensation, nucleation and transport nanosize particles. Modelling is essential in parametric scans in radiation source optimization, in fast particles and debris generation to solve current EUVL source problems as well as extending their application. 8

29 Acknowledgements EPPRA SAS, Villebon/Yvette, France Raul Aliaga-Rossel Keldysh Institute of Applied Mathematics RAS, Moscow, Russia Vladimir G. Novikov, Andrey V. Berezin, Mikhail B. Markov, Alex Yu. Krukovskiy Joint Institute of High Temperatures RAS, Moscow, Russia SRC TRINITI, Moscow, Russia University College Dublin - School of Physics, Dublin, Ireland Czech Technical University in Prague EUVA, Manda Hiratsuka, Japan RWTH Experimental Physics, Aachen, Germany TRINITY College Dublin EUV LITHO, Inc Valentin P. Smirnov Vladimir M. Borisov Gerry O Sullivan, Padraig Dune, Emma Sokel, John White Miroslava Vrbova, Pavel Vrbov Georg Soumagne Larissa Juschkin Isaac Tobin, James Lunney Vivek Bakshi Sponsors - EU & French Government ANR- EUVIL FP7 IAPP 9