High brightness EUV light source High brightness EUV light source system development for actinic mask system development for actinic mask

metrologymetrology

Sergey V. Zakharov, Peter Choi, Raul Aliaga-Rossel, Adrice Bakouboula, Otman Benali, Philippe Bove, Michele Cau, Grainne Duffy, Carlo Fanara,Wafa Kezzar,

Blair Lebert, Keith Powell, Ouassima Sarroukh, Luc Tantart, Clement Zaepffel, Vasily S. Zakharov, Edmund Wyndham *

NANO-UV sasEPPRA sas

* Edmund Wyndham is with the Pontificia Universidad Catolica de Chile

COST MP0601

WG & MC Meetings27-28 May

2010 Krakow Poland

2

Challenges to EUVL deployment

Special light source for mask inspection

ZETA-Z* RMHD codes

Non-equilibrium plasma kinetic model

plasma radiance limithighly charged Xe ion EUV emission

Combined Nd:YAG-CO2 laser pulse

Nano-UV: EUV and soft X-ray source

Multiplexed high brightness EUV sources

Summary

Challenges to EUVL deployment

Special light source for mask inspection

ZETA-Z* RMHD codes

Non-equilibrium plasma kinetic model

plasma radiance limithighly charged Xe ion EUV emission

Combined Nd:YAG-CO2 laser pulse

Nano-UV: EUV and soft X-ray source

Multiplexed high brightness EUV sources

Summary

OutlineOutline

COST MP0601

WG & MC Meetings27-28 May

2010 Krakow Poland

3

EUV (13.5nm wavelength) lithographyEUV (13.5nm wavelength) lithography chosen for nano features microchip productionchosen for nano features microchip production

HP

EUV source for HVM & actinic mask inspectionEUV source for HVM & actinic mask inspection - a key challenge facing the industry - a key challenge facing the industry

COST MP0601

WG & MC Meetings27-28 May

2010 Krakow Poland

4

Remaining Focus AreasRemaining Focus Areas

- light source for Litho and mask inspection

critical -

EUVL Symposium, Tahoe 2008

EUVL Symposium, Prague 2009

1 - Long-term source operation with 100 W at the IF and 5 megajoule per day

2 - Availability of defect-free masks, throughout a mask lifecycle, and the need to address critical mask infrastructure tool gaps, specifically in the defect inspection and defect review area

3 - …

1 - Mask yield & defect inspection/review infrastructure

2 - Long-term source operation with 115 W at the IF for 5mJ/cm2 resist sensitivity or with 200W at the IF for 10mJ/cm2 resist sensitivity

3 - …

COST MP0601

WG & MC Meetings27-28 May

2010 Krakow Poland

5

Consider a CCD array (nn) detector, pixel size Ap, being used to image the area of the mask under inspection

- magnification of imaging optics, m, hence area to detect a defect is now Ai=Ap/m2, and the total illuminated patch area on mask observed is A=Ai·n2

- relative defect response > N photon statistics

- total illumination time: t =tA·M·m2/n2·Ap

- illuminating irradiance required:

*additional time for positioning and alignment needed in each exposure

EUV Brightfield MetrologyEUV Brightfield Metrology - requirements- requirements

M

DNA

N

A

Ai

- then for defect size 10 nm, a (9m)2 pixel size, 20482 CCD array and full size (42(2633) mm2) mask inspection:

22

4

ntD

M

RtA

N

A

A

Magnification, m 40 80 160

Patch area, A (um2) 5.06E-02 1.27E-02 3.16E-03

Illuminating flux density (ph/cm2) 5.47E+15 1.37E+15 3.42E+14

Na illuminating A 1.16E+13 7.26E+11 4.54E+10

Irradiance at mask needed, 10 shots exposure (ph/s cm2) 2.74E+18 6.84E+17 1.71E+17

Mask exposure time (min) 2.16E+00 8.62E+00 3.45E+01

(reflectivity R60%)

COST MP0601

WG & MC Meetings27-28 May

2010 Krakow Poland

6

Actinic Mask Inspection Actinic Mask Inspection - - key source requirementskey source requirements based on current studiesbased on current studies

- High-brightness, small-etendue, high-repetition-rate, and clean light source is preferable

Source Workshop 2009 Baltimore

COST MP0601

WG & MC Meetings27-28 May

2010 Krakow Poland

7

R(cm)

Z(c

m)

-0.2 -0.1 0 0.1 0.2

0.5

1

1.5

2

2.5

3

3.5t= 4.7614E+00 ns

Anode

Cathode

cap

illa

ry

cap

illa

ry

Anode

Cathode

Frame 001 21 Feb 2005 ZSTAR - code output, cell values

EUV Light SourceEUV Light Source - in practice- in practice

• Sn, Xe, Li … high energy density plasma - narrow 2% band

@ 13.5nm source of EUV light

• LPP & DPP - methods to produce the the right conditions HED plasma

- kW (source) W (IF) is the source of the problem -

combined NdYAG +CO2

• For HVM - at least 200-500 W of in-band power @ IF

with etendue < 3mm2sr is required

DPP

Z * MHD code modeling

LPP

micro plasma

COST MP0601

WG & MC Meetings27-28 May

2010 Krakow Poland

8

ZETA ZETA Z Z* * RMHD Code RMHD Code ZZ* * BMEBME

physical model physical modelTables (Te,ρ) for solid matter & for LTE, non-LTE plasmas of ion compositions:EOS ; ionization distribution; rates; non-maxwell electrons; spectral group radiation & transport coefficients

EEMHD in real cylindrical geometry:dynamics of electrons change to 3D PIC;ionization of weekly ionized plasma(hollow cathode ionization wave)

DPPDPPsimulationsimulation

in real geometryin real geometry

LPPLPP

Data: (r,z,v,Te,I ,ρ,E, B,

Z,Uω, etc);time evolution (I,Pω ,W, Fω , etc);visualization

Spectral postprocessing: 3D ray tracing; detailed spectra

Heat flux postprocessing:element lifetime estimation;fast particle flux, 3D PIC

RMHD with energy supply:

(r,z+φ) plasma dynamics in (E,B)r,φ,z;nonstationary, nonLTE ionization; spectral multigroup radiation transport in nonLTE with special spectral groups (for EUV,laser); solid elements sublimation, condensation, expansion into plasma

- Improved- new- coming

COST MP0601

WG & MC Meetings27-28 May

2010 Krakow Poland

9

No energy balance!

Numerical

diffusion!

Adaptive grid

Detailed grid?

Adaptive grid

?

Lagrange variables

Gridcrossing

!

RMHDLAGRANGE-

EULER VARIABLES

COMPLETELY CONSERVATIVE,

IMPLICIT SCHEME

Small time step! (zero for plasma in magnetic field)

Euler variables Explicit scheme is stable conditionally

Non-conservative scheme

PHYSICALSOLUTION

ZETA ZETA Z Z* * RMHD Code RMHD Code ZZ* * BMEBME

mathematical model: algorithms & schemes mathematical model: algorithms & schemes

COST MP0601

WG & MC Meetings27-28 May

2010 Krakow Poland

10

10-5

10-4

10-3

10-2

10-1

100

101

102

10-18 10-16 10-14 10-12 10-10 10-8 10-6 10-4 10-2

R=0.04mmR=0.08mmR=0.16mmR=0.31mmR=0.625mmR=1.25mmR=2.5mmR=5mm

EU

V R

adia

nce

, MW

/mm

2 sr

Effective Depth (rho2*r), g2/cm3

tin

0

0.05

0.1

0.15

10-18 10-16 10-14 10-12 10-10 10-8 10-6 10-4 10-2

R=0.04mmR=0.08mmR=0.16mmR=0.31mmR=0.625mmR=1.25mmR=2.5mmR=5mm

Spe

ctra

l Effi

cien

cy (

Peu

v/P

rad)

Effective Depth (rho2*r), g2/cm5

tin

EUV Brightness Limit of a Source EUV Brightness Limit of a Source

. - the Conversion Efficiency of a single source decreases if the in-band EUV output increases

(at the same operation frequency)

Z* Scan

g2/cm5

g2/cm5

• The intensity upper Planckian limit of a single spherical optically thick plasma source in /=2% band around =13.5nm

• Source with pulse duration and repetition rate f yields the time-average radiance L =I·( f)

• At T22eV L 1.1(W/mm2 sr)·(ns)·f(kHz)• For =2050ns L = 2050 (W/mm2 sr)/kHz.

• Plasma self-absorption defines the limiting brightness of a single EUV source and required radiance

• The plasma parameters where EUV radiance is a maximum are not the same as that when the spectral efficiency is a maximum.

)/(72/2 2

)(924

2

11srmmMW

hcI

ee eVTThc

COST MP0601

WG & MC Meetings27-28 May

2010 Krakow Poland

11

ns-order CO2 laser(main pulse)

sub-ns Nd:YAG laser(pre-pulse)

Target Chamber

Beam splitter

Collector Mirror

Sn Droplet Target

EUV / 13.5nm

Combined Nd:YAG - COCombined Nd:YAG - CO22 Laser System Laser System

COST MP0601

WG & MC Meetings27-28 May

2010 Krakow Poland

12

Z

R

Nd:YAG CO2delay time t

1.064m 10.6m

100 times lower density in case of a CO2 laser with respect to a Nd:YAG laser as the main pulse gives a chance

• to increase the EUV emission efficiency by lower reabsorption of EUV radiation

• to reduce debris using a small-size, i.e. low-mass, target

Combined Nd:YAG - COCombined Nd:YAG - CO22 Laser System Laser System

- layout- layout

COST MP0601

WG & MC Meetings27-28 May

2010 Krakow Poland

13

LPP Dynamics & EUV EmissionLPP Dynamics & EUV Emission

during pre- and main laser pulseduring pre- and main laser pulse

2.5mJ YAG laser pre-pulse energy.

Main laser pulse: CO2, 50mJ, 15ns, 100 m FWHM spot size.

The delay time between laser pulses is 75ns.

COST MP0601

WG & MC Meetings27-28 May

2010 Krakow Poland

14

20um Sn droplet, Nd:YAG: 2.5 & 5mJ, 10ns, 20um spot size;CO2: 50mJ & 100mJ, 15ns with 100um spot size; all fwhm

0

0.2

0.4

0.6

0.8

1

1.2

0 50 100 150delay time (ns)

CE

(2

pi,

2%

)

5mJ PrePulse2.5mJ PrePulse100mJ, 15&37ns100mJ, 15ns, 60ns

37ns

60ns

Target: 20m diameter Sn dropletPre-pulse laser: Nd:YAG, 10ns fwhm, 20m spot size, pulse energy 2.5 & 5mJMain pulse: CO2-laser, 15, 37 and 60ns fwhm, 100m spot size

Conversion Efficiency Conversion Efficiency

vs. pre-pulse to pulse delay timevs. pre-pulse to pulse delay time

2%

CE

(i

n 2

%)

EUV brightness up to EUV brightness up to 5 W/mm5 W/mm22 sr kHz sr kHz

COST MP0601

WG & MC Meetings27-28 May

2010 Krakow Poland

15

EUV IF Power Limitation: EUV IF Power Limitation: prediction vs. observationprediction vs. observation

• Xenon plasma EUV emissionXenon plasma EUV emission

Experimental observation of limitation of the EUV power at IF from xenon DPP source

[M. Yoshioka et al. Alternative Litho. Tech. Proc. of SPIE, vol. 7271 727109-1 (2009)]

Xenon plasma parameter scan with Z*-code showing the EUV radiance limitation

xenon

COST MP0601

WG & MC Meetings27-28 May

2010 Krakow Poland

16

T Kato et al. J. Phys. B: At. Mol. Opt. Phys. 41 (2008)

10-3

10-2

10-1

100

101

102

10-7 10-6 10-5 10-4 10-3 10-2 10-1 100

R=0.04mmR=0.08mmR=0.16mmR=0.31mmR=0.625mmR=1.25mmR=2.5mmR=5mm

EU

V R

adia

nce

, MW

/mm

2 sr

Mass Depth (rho*r), g/cm2

LT

xenon

HT

Z* Scan

• XeXXII - XeXXXproduce bright 4f-4d*, 4d-4p*, 5p-4d* [White, O’Sulivan] (3dn4f1 + 3dn4p1 3dn4d1) satellites in EUV range near 13.5nm

• XeXXII has ionization potential 619eV

Bright EUV Emission Bright EUV Emission from highly charged xenon ionsfrom highly charged xenon ions

Tokamak experimental data • There are two regimes in transparent plasma of xenon: Low - Temperature (LT) with XeXI and High - Temperature (HT) with XeXVII-XeXXX ions contributing into 2% bandwidth at 13.5nm.

• For small size xenon plasma, the

maximum EUV radiance in the HT can exceed the tin plasma emission

COST MP0601

WG & MC Meetings27-28 May

2010 Krakow Poland

17

0.01

0.1

1

5 10 15 20 25 30

without0.5%

1%1.5%

2%

Ion charge

Calculated ionic fractions without

and with fast electrons of 5keV

energy and various

percentage (0.5%-2%)

Plasma temperature

T = 40 eV

Electron densityNe=1017 cm-3

Rel

ativ

e io

nic

fra

ctio

nNon-Equilibrium Kinetics Non-Equilibrium Kinetics

Xe ions population vs. e- fractionXe ions population vs. e- fraction

details in poster: Vasily Zakharov“Modeling of EUV spectra from nonequilibrium xenon plasma with high energy electrons”

COST MP0601

WG & MC Meetings27-28 May

2010 Krakow Poland

18

Emission of Highly Charged Xe IonsEmission of Highly Charged Xe Ions - from e-beam triggered discharge plasma- from e-beam triggered discharge plasma

5 10 15 20 25

0

5000

10000

15000

20000

25000

30000

35000

40000

45000

50000

o.4

o.3

o.2

o.1

Wavelength (nm)

Inte

nsity

(arb

. uni

ts)

5 10 15 20 25

0

10000

20000

30000

40000

50000

60000

0.1

0.30.5

0.7

wavelength (nm)

inte

nsi

ty (re

l. units

)

EUV MeasurementCapillary discharge. VUV spectrograph data

Bright EUV emission in 2% band at 13.5 nm can be achieved from highly charged xenon ions in plasma with small percentage of fast electrons

details in the poster: Vasily Zakharov “Modeling of EUV spectra from nonequilibrium xenon plasma with high energy electrons”

COST MP0601

WG & MC Meetings27-28 May

2010 Krakow Poland

19

10-5

10-4

10-3

10-2

10-1

100

101

102

10-9 10-7 10-5 10-3 10-1

R=0.04mmR=0.08mmR=0.16mmR=0.31mmR=0.625mmR=1.25mmR=2.5mmR=5mm

EU

V R

adia

nce

, MW

/mm

2 sr

Mass Depth (rho*r), g/cm2

MultiplexingMultiplexing - a solution for high power & brightness- a solution for high power & brightness

- problem is the physical size of SoCoMo

Z* Scan

tin• Small size sources, with low enough etendue

E1=As << 1 mm2 sr can be multiplexed.

• The EUV power of multiplexed N sources is

The EUV source power meeting the etendue requirements increases as N1/2

• This allows efficient re-packing of radiators from 1 into N separate smaller volumes without losses in EUV power

fNEPEUV

• Spatial-temporal multiplexing: The average brightness of a source and output power can be increased by means of spatial-temporal multiplexing with active optics system, totallizing sequentially the EUV outputs from multiple sources in the same beam direction without extension of the etendue or collection solid angle

COST MP0601

WG & MC Meetings27-28 May

2010 Krakow Poland

20

DischargeVoltage

EUV diode

Spot-scan spatial profile

Nano-UV: Nano-UV: High Brightness EUV SourceHigh Brightness EUV Source

capillary discharge pulsed micro-plasmacapillary discharge pulsed micro-plasmaGEN-II CYCLOPS cells

Measured Performance• use SXUV20 Mo/Si filtered diode (IRD)

coated (110 nm Al) on Si3N4 (50 nm) to reject OoB

• 3 nm EUV band (12.4 nm -15.4 nm)• coated (110 nm Al) on Si3N4 (50 nm) to

reject OoB• irradiance measured at 44 cm - • 0.8 W/cm2/s at 1 kHz, 19 kV• beam FWHM - 7.4 mm, (1/e2) spot = 12.5

mm• EUV power at beam spot - 0.44W at 1 kHz• typical etendue 5.10-3 to 1.10-2 mm2.sr• discharge in He/Ar/Xe admixture

COST MP0601

WG & MC Meetings27-28 May

2010 Krakow Poland

21

Source CharacteristicsSource Characteristics- wavefront measurement- wavefront measurement

• EUV beam diameter d= 9.75 mm at 1890 mm from source

• Beam divergence half angle =0.19°

• Solid angle = 0.0345 msr• Etendue E = 2 R· · RMS

= 5 ·10-5

mm2srDerived wavefront166 nm RMS (12 )

& 760nm PV (58 )

HASO X-EUV Shack Hartmann wavefront sensor - (manufactured by Imagine Optic)

1890 mm

HASOEUV source

* With support of G. Dovillaire, E. Lavergne from Imagine Optic and P. Mercere, M.Idir from SOLEIL Synchrotron

Acquired image60s exposure,

source at 1 kHz

COST MP0601

WG & MC Meetings27-28 May

2010 Krakow Poland

23

Pre-ionization in capillary discharge (ion density ni ):- axial beam of run-away electrons,

- ionization of the gas by beam and secondary electrons, - the ionization wave forces out the electric field

Ionization cross-section of argon atoms

Capillary Discharge EUV SourceCapillary Discharge EUV Source

electron beam and ionization waveelectron beam and ionization wave

3-D volumetric compression:

Initial axial pressure gradient : m(z)=R02 0(z); R(t,z) ~ 0(z)-1/2

 

;R

Ij;

R

rcI2

B

;RR

rv;R

R

2z2

r2

2

00

;3 z

R

R

Irjr

z

ln

t2

t

t

t1ln

R

R

lnt2

r)t,z,r(v 0

00RR0

RR

0

2

z0

0

In particular, for the constant current I(t) = I0 and cylindrical capillary

with radius R0

Low thermal pressure , high magnetic field diffusion 8

B p

2

0

2 R2/tc

Volumetric compression

;R

I

mc

2R

2

2

m = R020 ;

IcR

mt0

00

)ln(Erftt 20 I(t) = I0

R

R0

t

02

2

2

2

z tdR

zR

mc

I

R

r2)t,z,r(v

;RI

mc

2R

2

2

RzR

mc

I2u 2

2

MHD of Radiating PlasmaMHD of Radiating Plasmacapillary discharge dynamicscapillary discharge dynamics

Long capillary: L>>R0Radial current:

2z rv)t,z(u

R

Rrvr

COST MP0601

WG & MC Meetings27-28 May

2010 Krakow Poland

25

At EUV emission maximum

=510-7g/cm3, Те=18eV.

Without taking into account of fast electrons the plasma ionization degree is <Z>=7.3; EUV yield is 6J.

WITH 0.1% of fast electrons <Z>=8.8;

EUV yield is 30J (26 J in experiment).

Capillary Discharge EUV SourceCapillary Discharge EUV Source increasing ionization degree effectincreasing ionization degree effect

3D volumetric compressionPlasma density dynamics

COST MP0601

WG & MC Meetings27-28 May

2010 Krakow Poland

26

19kV charge, 1.2 nF capacitor >19kV charge energy scan

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

0 5 10 15 20 25 30 35 40

in-b

an

d E

UV

po

we

r, k

W

time, ns

Peuv, kW

-6

-5

-4

-3

-2

-1

0

1

2

3

4

0 5 10 15 20 25 30 35 40

dis

ch

arg

e c

urr

en

t, k

A

time, ns

I, kA

EEUV =56J/shot

P =56mW/kHz

0

50

100

150

200

250

0 100 200 300 400 500

In-b

an

d E

UV

en

erg

y p

er

sh

ot,

mJ

Stored energy, mJ

in-b

and

EU

V e

nerg

y pe

r sh

ot,

J

Gen II Gen II EUV SourceEUV Source

- - characteristics from Z* modellingcharacteristics from Z* modelling

0,20 0,22 0,24 0,26 0,28 0,300,0

0,5

1,0

1,5

2,0

2,5

peak irradiance linear fit of data

Irra

dia

nce

at

pe

ak

sig

na

l

(x 1

017

ph

/cm

2 /s)

Stored energy (J)

Energy scan calculated

(in 2% band)

Experimental energy scan

(20% band)

COST MP0601

WG & MC Meetings27-28 May

2010 Krakow Poland

27

plasma dynamics spectral radiation transport non-equilibrium atomic kinetics with fast electrons transport of fast ions/electrons condensation, nucleation and transport nanosize particles.

• Modelling can be the key factor to scientific and technological solutions in EUVL source optimization with fast particles and debris to solve current EUVL source problems as well as extending their application to 22nm and beyond.

• The research and transfer of knowledge is focused on two major modeling applications;

EUV source optimization for lithography and nanoparticle production for nanotechnology.

• Theoretical modelling will be benchmarked by LPP and DPP experiments

Next Generation Modelling ToolsNext Generation Modelling Tools - FP7 IAPP project - FP7 IAPP project FIREFIRE

• Theoretical models and robust modeling tools are developed under international collaboration in the frames of European FP7 IAPP project FIRE

• The FIRE project aims to substantially redevelop the Z* code to include improved atomic physics models and full 3-D plasma simulation of

COST MP0601

WG & MC Meetings27-28 May

2010 Krakow Poland

28

HYDRAHYDRA™™-ABI -ABI - spatial multiplexing for blank inspection- spatial multiplexing for blank inspection

• Design Specifications

– 60 W/mm2.sr in-band 2% EUV radiant brightness at the IF

– 0.6 W at the IF– etendue 10-2 mm2.sr – source area - 31 mm2 / TBD– optimized for mask blank inspection– 4x i-SoCoMo units working at 3 kHz each– no debris / membrane filter– close packed pupil fill

• Current Status

– 4 units integration & characterization– single unit optimization– ML mirrors evaluation & modelling

COST MP0601

WG & MC Meetings27-28 May

2010 Krakow Poland

29

HYDRAHYDRA44-ABI-ABI™™ - pupil arrangements- pupil arrangements

Source 1 only Source 2 only

Source 4 only Source 3 only

Each source turned on separately and aligned to a different corner

• Radiation observed on a fluorescent screen 70 cm downstream

ALL 4 Sources

All 4 sources aligned to a point

25 mm

COST MP0601

WG & MC Meetings27-28 May

2010 Krakow Poland

30

• Design Specifications – 100 W/mm2.sr in-band 2% EUV brightness– 2.4W at the IF– etendue - 2.4 10-2 mm2.sr (50% fill pupil)– source area - 4 mm2 / variable sigma– optimized for aerial image measurements– 12x i-SoCoMo units, 5 kHz working each– no debris / membrane filter– variable pupil fill and sigma

• Current Status

– system characterization– single unit optimization– ML mirrors modelling

curved ML

plane ML

HYDRAHYDRA™™-AIMS-AIMS - spatial multiplexing with variable sigma- spatial multiplexing with variable sigma

COST MP0601

WG & MC Meetings27-28 May

2010 Krakow Poland

31

HYDRAHYDRA12-12-AIMSAIMS™™ - prototype system- prototype system

A EUV Source for Mask Metrology

COST MP0601

WG & MC Meetings27-28 May

2010 Krakow Poland

32

HYDRAHYDRA™™-APMI -APMI - unique temporal & spatial multiplexing- unique temporal & spatial multiplexing

• Design Specifications – 1200 W/mm2.sr in-band EUV radiant brightness– 2.4 W at the IF– etendue - 2. 10-3 mm2.sr – source area - 20 mm2

– optimized for patterned mask inspection– 8x i-SoCoMo units working at 3 kHz each– 24 kHz temporally multiplexed– no debris / membrane filter– Gaussian output spot

• Current Status

– optics design & modelling– single unit optimization– mechanical design

COST MP0601

WG & MC Meetings27-28 May

2010 Krakow Poland

33

• Knowledge of the behaviour of multicharged ion non-equilibrium plasma with ionization phenomena, radiation and fast particles transfer is critical for EUV source development

• Self-absorption defines the limiting brightness of a single EUV source, required for the HVM and AIM tools with high efficiency at given the limiting etendue of the optics

• Extra EUV in-band emission may be achieved from highly charged Xe ions in plasma

with fast electrons

• The required irradiance can be achieved by spatial multiplexing, using multiple small sources

• NANO-UV presents a high brightness EUV light source unit, incorporating the i-SoCoMo technology, together with early experiences of operating sources in a multiplexed configuration, which can satisfy the source power and brightness requirements for an at-line tools for actinic mask inspection and in future for HVM .

SummarySummary

COST MP0601

WG & MC Meetings27-28 May

2010 Krakow Poland

34

• R&D team & collaborators

– R&D team of EPPRA and Nano-UV– Pontificia Universidad Catolica de Chile– RRC Kurchatov Institute, Moscow,

Russia– Keldysh Institute of Applied

Mathematics RAS, Moscow, Russia

– University College Dublin– King’s College London– EUVA, Manda Hiratsuka, Japan

• Sponsors - EU & French Government– ANR- EUVIL– FP7 IAPP– OSEO-ANVAR

• RAKIA

• COST

AcknowledgementAcknowledgement

COST MP0601

WG & MC Meetings27-28 May

2010 Krakow Poland

35

20 20 m Sn-droplet,m Sn-droplet,2.5mJ Nd:YAG pre-pulse, 10ns fwhm2.5mJ Nd:YAG pre-pulse, 10ns fwhm50mJ CO50mJ CO22 main-pulse, 15ns fwhm main-pulse, 15ns fwhm

75ns delay time between both laser pulses75ns delay time between both laser pulses

in-band EUV, 2.5mJ pre-pulse, 50mJ main, 75ns delay

0.00

0.02

0.04

0.06

0.08

0 20 40 60 80 100 120

time (ns)

EU

V (M

W, 2

%, 4

pi)

laser pulse; 2.5mJ pre-pulse, 50mJ main, 75ns delay

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

0 20 40 60 80 100 120

time (ns)

lase

r po

wer

(MW

)

absorption

laser pulse

EUV emission Laser pulse shapes

Combined Nd:YAG-CO2 laser pulses laser absorption & EUV emission

COST MP0601

WG & MC Meetings27-28 May

2010 Krakow Poland

36

• heating of the electrodes by joule dissipation at electrode-plasma transition;

thermal instability:

• surface heating & plasma cooling by means of plasma thermal

conduction; • surface heating and damage by plasma radiation;

• optical elements damage by fast ions & atoms emitted from the plasma (ambipolar and E-field acceleration, shocks, Maxwell tails etc).

Tθ

σ~σ(T) 0 σj

tT

c2

v

tdγ0 eTT

v0

2

cθσj

γ

Plasma-electrode interaction mechanismsPlasma-electrode interaction mechanisms

COST MP0601

WG & MC Meetings27-28 May

2010 Krakow Poland

37

(zoomed)(zoomed)

Heat loading on electrodes Heat loading on electrodes and insulatorand insulator Z*BME modellingZ*BME modelling

R(cm)

Z(c

m)

0.05 0.1 0.15 0.2 0.25 0.3

1

2

3

4

5dTel(C)

200.00191.74183.48175.22166.96158.70150.43142.17133.91125.65117.39109.13100.87

92.6184.3576.0967.8359.5751.3043.0434.7826.5218.2610.00

t= 0.804s

Anode

Cathode

Insulator

Ca

pill

ary

Frame 001 14 Oct 2006 ZSTAR - code output, cell values

Capillary discharge:

Charge energy 0.4J/pulse Operation frequency 3kHz

Low energy unit provides:

• Low heat loading on electrodes and insulators

• Long lifetime

• Low debris production

141 M_shots