High intensity EUV and soft X-ray plasma sources … · 2010 International 2010 International Workshop on Extreme Ultraviolet Sources University College Dublin, Ireland, November

2010 International 2010 International Workshop on Extreme Ultraviolet Sources University College Dublin, Ireland,

November 13-15, 2010

High intensity EUV and soft XHigh intensity EUV and soft X--ray ray plasma sources plasma sources modellingmodelling

Sergey V. Zakharov+, Vasily S. Zakharov+,Peter Choi, Alex Yu. Krukovskiy, Vladimir G. Novikov, Anna D. Solomyannaya

NANO‐UV sasEPPRA sasKIAM RAS

+

also with RRC Kurchatov

Institute

2010 International Workshop on EUV SourcesUCD, Dublin

Ireland

COPYRIGHT 2010 NANO‐UV

ABSTRACT ABSTRACT The average power of EUV sources at IF required for lithography HVM is higher than presently available. At the same time, for actinic mask blanks, patterned mask and in-situ inspection tools, EUV sources of moderate power but very high brightness are required. In practice, the non-equilibrium plasma dynamics and self-absorption of radiation limits the in-band EUV radiance of the source plasma, and the etendue constraint limits the usable power of a conventional single unit EUV source. Under those conditions one of the primary goals in the development of EUVL is the modelling of plasma-based light sources created by intense lasers and high-current pulsed discharges. A new generation of the computational code Z* is currently developed under international collaboration in the frames of FP7 IAPP project FIRE for modelling of multi-physics phenomena in radiation plasma sources to contribute considerably to solving current EUVL source problems as well as extending their application to subsequent nodes (16nm and beyond) and to shorter wavelength radiation applications. The radiation plasma dynamics, the spectral effects of self-absorption in LPP and DPP and resulting conversion efficiencies are discussed. The modelling results are guiding a new generation of multiplexed sources being developed at NANO-UV, based on spatial/temporal multiplexing of individual high brightness units, to deliver the requisite brightness and power for lithography, actinic metrology and soft X- ray imaging applications.


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EUV LithographyEUV Lithographychosen for chosen for nanonano features microchip productionfeatures 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

NOWNOWEUV to EUV to

16 nm HVM16 nm HVM


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EUV Light SourceEUV Light Source• Sn, Xe, Li … high energy density plasma (Te =20-40eV) - EUV light

source in narrow 2% band around 13.5nm wavelength• LPP & DPP - methods to produce the the right conditions for HED plasma

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

-

combined NdYAG

+CO2

• For HVM - 200-500 W of in-band power @ IF with etendue < 3mm2sr • For mask inspections ABIAIMSAPMI – 10 100 1000 W/mm2·sr

at-wavelength radiance

DPP

Z * MHD code modeling

LPPmicro plasmaDPP

I = 1011 W/cm2

Te = 40eVNe =1019-1021 cm-3

j = 1 - 10 MA/cm2

Te = 20-30eVNe =1015-1017 cm-3


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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


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ZETA ZETA ZZ* * RMHD Code RMHD Code ZZ* * BMEBME complete physical modelcomplete physical model

DPPDPPsimulationsimulation

in real in real geometrygeometry

LPPLPP

Data output:r,z,v,Te,i

,ρ,E,B,Z,Uω

, etc;visualization

RMHD

(r,z+φ) with: • spectral multigroup

radiation transport in nonLTE;

• nonstationary, nonLTE

ionization; • sublimation –

condensation;• energy supply (electric power, laser)• etc

TABLESnonLTE

atomic & spectral data

(Te,ρ,U)

EMHD or 3D PIC

with:ionization of weekly

ionized plasma

Spectral postprocessing

Heat flux postprocessing


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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

EUV

Rad

ianc

e, M

W/m

m2

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


Spec

tral E

ffici

ency

(Peu

v/Pr

ad)

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)

• 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

11srmmMWhcI

ee eVTThc


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

• Low temperature Xenon plasma EUV emission

Experimental observation of limitation of the in- band 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 in- band radiance limitation from XeI-XeXI ions

xenon


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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


EUV

Rad

ianc

e, M

W/m

m2

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

(for more details see poster: Vasily S. Zakharov et al)


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R(cm)

Z(cm

)

-0.04 -0.02 0 0.02 0.040.2

0.22

0.24

0.26

0.28

0.3DENS(g/ccm)

5.5E+003.3E+002.0E+001.2E+007.4E-014.5E-012.7E-011.7E-011.0E-016.1E-023.7E-022.2E-021.4E-028.2E-035.0E-033.0E-031.8E-031.1E-036.7E-044.1E-042.5E-041.5E-049.1E-055.5E-05

t= -1.8000E+01 ns

laser

Frame 001 12 Oct 2010 ZSTAR - code output, cell values

R(cm)

Z(cm

)

-0.04 -0.02 0 0.02 0.040.2

0.22

0.24

0.26

0.28

0.3DENS(g/ccm)

5.5E+003.3E+002.0E+001.2E+007.4E-014.5E-012.7E-011.7E-011.0E-016.1E-023.7E-022.2E-021.4E-028.2E-035.0E-033.0E-031.8E-031.1E-036.7E-044.1E-042.5E-041.5E-049.1E-055.5E-05

t= 1.9246E+01 ns


LPP Dynamics LPP Dynamics under COunder CO22 -- laser pulselaser pulse

40m tin dropletplasma mass

density

CO2

-laser pulse:Pulse energy 200mJPulse duration 15ns FWHMFocal spot size 200 m

0

2

4

6

8

10

12

14

-20 -10 0 10 20 30 40 50 60

Pow

er, M

W

Time, ns

irradiationabsorption

Loses: reflections and large focal size at initial moment


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1.7E-06

1.7E-06

1.7E-06

1.7E-06

5.4E-0

6

5.4E-06

5.4E-06

1.7E-05

1.7E-05

5.4E-055.4

E-05

5.4E-05

1.7E-04

R(cm)

Z(cm

)

-0.04 -0.02 0 0.02 0.040.2

0.22

0.24

0.26

0.28

0.3Ne(Av)

1.7E-035.4E-041.7E-045.4E-051.7E-055.4E-061.7E-06

t= 1.9246E+01 ns


0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

-20 -10 0 10 20 30 40 50 60

Pow

er, M

W

Time, ns

EUV emission

R(cm)

Z(cm

)

-0.04 -0.02 0 0.02 0.040.2

0.22

0.24

0.26

0.28

0.3Qeuv(J/ccm)

4.0E+043.8E+043.7E+043.5E+043.3E+043.1E+043.0E+042.8E+042.6E+042.4E+042.3E+042.1E+041.9E+041.7E+041.6E+041.4E+041.2E+041.0E+048.7E+037.0E+035.2E+033.5E+031.7E+03

-1.0E+00

Time-integrated


EUV EmissionEUV Emission under COunder CO22 -- laser pulselaser pulse

R(cm)

Z(cm

)

-0.04 -0.02 0 0.02 0.040.2

0.22

0.24

0.26

0.28

0.3Te(eV)

8.4E+018.1E+017.7E+017.4E+017.0E+016.7E+016.3E+016.0E+015.6E+015.3E+014.9E+014.6E+014.2E+013.9E+013.5E+013.2E+012.8E+012.5E+012.1E+011.8E+011.4E+011.1E+017.0E+003.5E+00

t= 1.9246E+01 ns


plasma electron

temperatureTe

plasma electron density

Ne

in 2% @ 13.5nm

EUV source cross-section


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Main pulse: CO2 -laser 0.2 J/pulse, 15, 30 and 50ns fwhm, 200m focal spot sizePre-pulse laser

(if applied): Nd:YAG 5 mJ/pulse, 10ns fwhm, 40m spot size

Conversion Efficiency of COConversion Efficiency of CO22 --laser laser on pulse duration, with & w/out preon pulse duration, with & w/out pre--pulsepulse

Calculated EUV Calculated EUV brightness is up to brightness is up to 24 W/mm24 W/mm22 srsr kHzkHz

Target:40m diameter tin droplet(20 m for 100mJ laser)

0

0.5

1

1.5

2

2.5

3

0 10 20 30 40 50 60

Con

vers

ion

Effic

ienc

y, %

Pulse duration, ns

200mJ w/out pre-pulse200mJ with 5mJ pre-pulse

100mJ with pre-pulse (EUVA)

Z* Scan


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Capillary Discharge EUV SourceCapillary Discharge EUV Source resistive regimeresistive regime

-5

-4

-3

-2

-1

0

1

2

0 20 40 60 80 100

Dis

char

ge c

urre

nt, k

A

Time, ns

In a 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 consequently.

Also, fast electrons increase the ionization degree of heavy ion (Xe,…) plasma increasing eo ipso EUV yield.

-6-5-4-3-2-1 0 1 2 3 4

0 5 10 15 20 25 30 35 40

disc

harg

e cu

rren

t, kA

time, ns

I, kA

Inductive regime Resistive regime

19kV charge 1.2 nF capacitor

23kV charge 1.9 nF capacitor


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At EUV emission maximum:

Ne =2-3 1016cm-3, Te =25-40eV.

R(cm)

Z(cm

)

0 0.5

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

2.2

2.4 Ne(Av)

1.0E-078.2E-086.7E-085.5E-084.5E-083.7E-083.0E-082.5E-082.0E-081.6E-081.4E-081.1E-089.0E-097.4E-096.1E-095.0E-094.1E-093.3E-092.7E-092.2E-091.8E-091.5E-091.2E-091.0E-09

t= 3.3114E+01 ns

Cathode

Anode

capi

llary

capi

llary

Frame 001 12 Oct 2010 ZSTAR - code output, cel

Capillary Discharge EUV SourceCapillary Discharge EUV Source dynamics & EUV emissiondynamics & EUV emission

3D volumetric compression Calculated EUV brightness is up to Calculated EUV brightness is up to

10 W/mm10 W/mm22 srsr kHzkHz

0

0.01

0.02

0.03

0.04

0.05

0 20 40 60 80 100

Pow

er, M

W

Time, ns

EUV emissionin 2% @ 13.5nm

496mJ stored energy

R(cm)

Z(cm

)

0 0.5

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

2.2

2.4 Qeuv(J/ccm)

1.0E+009.7E-019.4E-019.1E-018.8E-018.5E-018.2E-017.9E-017.6E-017.3E-017.0E-016.7E-016.3E-016.0E-015.7E-015.4E-015.1E-014.8E-014.5E-014.2E-013.9E-013.6E-013.3E-013.0E-01

Time-integrated

Cathode

Anode

capi

llary

capi

llary

Frame 001 13 Oct 2010 ZSTAR - code output, cel

EUV source cross-section


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Gen II Gen II EUV SourceEUV Source -- characteristics & optimization from Zcharacteristics & optimization from Z** modellingmodelling

0

200

400

600

800

1000

200 250 300 350 400 450 500 550 600

In-b

and

EUV

ener

gy p

er s

hot,

uJ

Stored energy, mJ

Energy scan calculated

(in 2% band)

Optimization by gas mixture pressure

EUV source scan by stored electrical energy

0

200

400

600

800

1000

0 5 10 15 20 25 30

In-b

and

EUV

ener

gy p

er s

hot,

uJ

Pressure, a.u.

885J/shot

496mJ stored energy


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10-5

10-4

10-3

10-2

10-1

100

101

102

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


EUV

Rad

ianc

e, M

W/m

m2

sr

Mass Depth (rho*r), g/cm2

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

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


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MPP source for soft xMPP source for soft x--ray microscopyray microscopyZ*-code modelling

Time integrated image of soft x-ray (400 -

600eV) sourceNitrogen plasma

at emission maximum

0.48J/pulse chargeFast electrons induced

discharge in 3-D volumetric

compression regime

Discharge current and soft x-ray pulse

<Z>

5Te = 45 -

55eVNe

2·1017cm-3

Nitrogen: He-like and H-like

R(cm)

Z(cm

)

-0.2 0 0.2

0.5

1

1.5

2

Ne(Av)

3.6E-073.4E-073.3E-073.1E-073.0E-072.8E-072.7E-072.5E-072.3E-072.2E-072.0E-071.9E-071.7E-071.6E-071.4E-071.3E-071.1E-079.4E-087.8E-086.3E-084.7E-083.1E-081.6E-08

t= 1.9037E+01 ns

anode

cathode

capi

llary

capi

llary

Frame 001 13 Aug 2010 ZSTAR - code output, cell values

R(cm)

Z(cm

)

-0.2 0 0.2

0.5

1

1.5

2Qww(J/ccm)

0.550.520.480.450.420.380.350.320.280.250.220.180.150.120.080.05

time integrated

anode

cathode

capi

llary

capi

llary

Frame 001 13 Aug 2010 ZSTAR - code output, cell values

0.48J/pulse charge


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• 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

High intensity EUV and soft X-ray plasma sources … · 2010 International 2010 International Workshop on Extreme Ultraviolet Sources University College Dublin, Ireland, November

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