Development of CO2 Laser Produced Xe Plasma EUV Light ...euvlsymposium.lbl.gov/pdf/2005/pres/13 1-IN-11 Mizoguchi.pdf · High-power CO2 laser Xe droplet target Magnetic field ion

1 4th International EUVL Symposium 2005

Development of CODevelopment of CO2 2 Laser Produced Xe PlasmaLaser Produced Xe PlasmaEUV Light Source for MicrolithographyEUV Light Source for Microlithography

EUVAEUVA(Extreme Ultraviolet Lithography System Development Association)

Hakaru Mizoguchi*, Akira Endo, Tatsuya Ariga, Taisuke Miura, Hideo Hoshino, Yoshifumi Ueno, Masaki Nakano, Hiroshi Komori, Tamotsu Abe,

Takashi Suganuma, Georg Soumagne, Hiroshi Someya, Yuichi Takabayashi, Koichi Toyoda

4th International EUVL Symposium7 November, 2005

San Diego, CaliforniaVer. 1.0

AcknowledgementsThis work was supported by the New Energy and Industrial This work was supported by the New Energy and Industrial

Technology Development Organization (NEDO), Japan.Technology Development Organization (NEDO), Japan.


Back ground and development roadmap Back ground and development roadmap Nd:YAG laser and Xenon jet based EUV sourceNd:YAG laser and Xenon jet based EUV source

Status of highStatus of high--power Nd:YAG laser and Xenon jetpower Nd:YAG laser and Xenon jetEUV light source by COEUV light source by CO22 laser driven Xe droplets laser driven Xe droplets

HighHigh--powerpower COCO22 laserlaserXe droplet targetXe droplet targetMagnetic field ion mitigation Magnetic field ion mitigation

Latest result and summaryLatest result and summary

OutlineOutline


Issues for EUV source developmentIssues for EUV source development

EUVL Light Source RequirementsEUVL Light Source Requirements (100 wafer/hr throughput, 300mm wafer)(100 wafer/hr throughput, 300mm wafer)

■■ 115W EUV in115W EUV in--band power (intermediate focus)band power (intermediate focus)■■ ±±0.3% energy stability (30.3% energy stability (3σσ, 50 pulses moving average), 50 pulses moving average)■■ Acceptable Initial cost and CoO Acceptable Initial cost and CoO

Issues of Source DevelopmentIssues of Source Development■■ High Conversion Efficiency (CE)High Conversion Efficiency (CE)

laser optimization, e.g. laser pulse energy & laser pulse widthlaser optimization, e.g. laser pulse energy & laser pulse width■■ High Repetition Rate Laser (>10kHz)High Repetition Rate Laser (>10kHz)

achieve EUV energy stability increasing the integral pulse numbeachieve EUV energy stability increasing the integral pulse numberr■■ Driver Laser Choice for Driver Laser Choice for Initial costInitial cost

introduction of industrial CO2 laserintroduction of industrial CO2 laser■■ Mirror Lifetime Extension for CoOMirror Lifetime Extension for CoO

magnetic field ion mitigationmagnetic field ion mitigation


Item1st Mid term

2004/92nd Mid term

2006/3EUVA Final

2008/3HVM Source

(2009)

5.7W---

YAG:1.5kW10kHz0.9%

Xe-Jet

115W3s<±0.3%

CO2*: 60kW100kHz

0.7%Xe-Droplet

10Ws<±10%

CO2*:6.8kW100kHz

0.5%Xe-Droplet

EUV Power (IF)StabilityLaser

Laser freq.CE (source)

Target

50Ws <±5%

CO2*: 30kW100kHz

0.6%Xe-Droplet

with Pre-Pulse YAG Laser*Technology for 10WTechnology for 10WNd:YAG Laser, Liquid Xe jet

Technology for 115WTechnology for 115WCO2 Laser, droplet targetMagnetic field mitigation

LPP EUV source roadmapLPP EUV source roadmap


Back ground and development roadmapBack ground and development roadmapNd:YAG laser and Xenon jet based EUV sourceNd:YAG laser and Xenon jet based EUV source

Status of highStatus of high--power Nd:YAG laser and Xenon jetpower Nd:YAG laser and Xenon jetMerit of Merit of COCO22 laser and Xe dropletslaser and Xe droplets

EUV light source by CO2 laser driven Xe droplets EUV light source by CO2 laser driven Xe droplets HighHigh--power CO2 laserpower CO2 laserXe droplet targetXe droplet targetMagnetic field ion mitigation Magnetic field ion mitigation


OutlineOutline


•• EUV Power at Source: EUV Power at Source: 13.3W13.3W (2%BW/2(2%BW/2ππsr)sr)

at I.F.:at I.F.: 5.7W5.7W (Calculated)(Calculated)•• Conversion Efficiency:Conversion Efficiency: 0.9%0.9%•• EUV Energy Stability:EUV Energy Stability: 1.3% 1.3% (1(1σσ, 50, 50--pulse ave.)pulse ave.)

•• Laser Power: Laser Power: 1500W@10kHz, 6ns1500W@10kHz, 6ns•• Target: Target: Liquid Xenon jetLiquid Xenon jet

0.0

0.5

1.0

1.5

2.0

2.5

0 20 40 60 80 100 120 140 160 180 200

Number of pulses

In-b

and

EUV

ener

gy [m

J]

EUV output with 1.5EUV output with 1.5--kW YAG laser and Xe jetkW YAG laser and Xe jet


1.51.5--kW Nd:YAG laser systemkW Nd:YAG laser system

Isolator

50W50W6.8ns6.8ns

415W415W6.3ns6.3ns

6W6W7ns7ns

Master OscillatorRep. rate: 10kHz

Pre Amp.

Main Amp.

Booster Amp.

1000W1000W

1000 W1000 W

1500W1500W500 W500 W

[Description ]・Nd:YAG MOPA※ System・Output power：1500W・Repetition rate：10ｋHz・Pulse duration：6ns(FWHM)

※ MOPA : Master Oscillator and Power

Amplifier


Xenon jet targetXenon jet target

Xenon jetXenon jet•• Jet diameter:Jet diameter: Approx. 50Approx. 50μμmm•• Jet speed:Jet speed: >35m/s>35m/s•• Jet stability:Jet stability: 9% (19% (1σσ))

@ 30mm from nozzle@ 30mm from nozzle

30m

m30

mm

Behavior afterBehavior afterlaser irradiation laser irradiation (115mJ, 2Hz)(115mJ, 2Hz)

-- Break up length Break up length 1mm/pulse1mm/pulse-- Deformation length Deformation length 3mm/pulse3mm/pulse

Xenon Xenon JetJet

LaserLaser

3 mm

1 mm



Status of highStatus of high--power Nd:YAG laser and Xenon jet power Nd:YAG laser and Xenon jet EUV light source by COEUV light source by CO22 laser driven Xe droplets laser driven Xe droplets

HighHigh--powerpower COCO22 laserlaserXe droplet targetXe droplet targetMagnetic field ion mitigationMagnetic field ion mitigation


OutlineOutline


Technical challenge for Xe jet target LPP Technical challenge for Xe jet target LPP

High power laser systemHigh power laser systemLaser beam quality degradation by thermal wave

front distortion in a Nd:YAG laser rod. Thin disk laser / Gas laserThin disk laser / Gas laser

High initial cost due to laser diode for optical pumping of Nd:YAG. COCO22 laserlaser

Xe jet target for high repetition rate irradiationXe jet target for high repetition rate irradiationContinuous Xe jet XeXe droplet targetdroplet targetShorter deformation length (1.5 mm 0.6 mm)Smaller required vacuum speed

(20,000 l/s 5,000 l/s)


Conversion Efficiency (CE) of 0.6% has been achieved (Xe Jet)

ns-order CO2 laser(main pulse)

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

Target Chamber

Beam splitter

Collector Mirror

Xe Droplet Target

EUV / 13.5nm

New LPP Light Source Concept New LPP Light Source Concept

Magnetic Field Ion Mitigation

B


0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.0E+00 1.0E+10 2.0E+10 3.0E+10 4.0E+10 5.0E+10 6.0E+10 7.0E+10

CO2 laser Power Intensity [W/cm2]

CE o

f CO

2 La

ser

LPP

with

Xe

Jet

15ns 25ns 45ns

Pre+15ns Pre+25ns Pre+45ns

Target

Max. CE = 0.6%

Pre-pulse laser increases CE significantly:

Conversion Efficiency of preConversion Efficiency of pre--pulsed CO2 laser Plasmapulsed CO2 laser Plasma


7kW (15ns, 70mJ,100kHz)

System operation：1Q/2006

Multiline CO2Short pulse osc.

RF-CO2 pre-amp

RF-CO2pre-amp

COCO22 laser based 10Wlaser based 10W--EUV systemEUV system

Xenon Droplets

RF-CO2 main amp

>10W@I/F

Magnetic field mitigation

Short pulse osc. has been developed.

Multiline seeder is under development

Industrial RF-CO2 lasers have been installed.

Amplification characteristics (g0, Es) have been investigated.

Pedestal has been controlled.

Pre-pulse

Nd:YAG

industrial NdYAG laser has been installed.

Short pulse operation has been optimized.

High speed Xe droplet is under development.

High speed water droplet has been optimized.

Effectiveness of magnetic field mitigation has been confirmed for pre-pulsed CO2.


1010--W EUV subsystem specificationsW EUV subsystem specifications

Item Detail Target specificationTarget Material Xe droplet

Diameter 20micronVelocity 100m/s

Frequency 2MHzCE 13.5nm, 2% BW, 2pi sr 0.5%

Driver laser Type Pre-pulsed CO2Amplification Multiline MOPA

Pulse duration 15nsPulse energy :PE 70mJ

Repetition rate: RR 100kHzOutput power 7kW

Collector mirror Solid angle: SA 5 srReflectivity :R 60%

Lifetime >5 BillionTransmittance Xe gas: T1 90%

Mitigation / Spectralpurity filter: T2 65%

EUV power at IF RExCExRRx(SA/2pi)xRxT1xT2 10 W






OutlineOutline


Main-AmplifierRF CO2 Laser

Fast Axial Gas Flow RF-Excited Type

Pre-AmplifierRF CO2 Laser

Fast Axial Gas Flow RF-Excited Type

Oscillator100W/15ns

Pulse CO2 Laser Wave Guide Type

Isolator

Gas Circulating PumpGas Cell

7 kW

~ 1 kW

0.1 kW

RF CORF CO22 driver laser system for 10W at IFdriver laser system for 10W at IF


RF-CO2 laser based 10-W LPP system

Pre-Amplifier (I)

Pre-Amplifier (II)

Main Amplifier

Beam Delivery

Target Chamber


Single Line

2-Lines3-Lines

6-Lines

Rooth et. al., J. Appl. Phys., 58, pp. 1120, (1985).

About twice of output energy was extracted by using 6-line amplification.

MultiMulti--line amplified COline amplified CO22 laser conceptlaser concept


Short pulse COShort pulse CO22 laser oscillator laser oscillator

Short pulse CO2 laser oscillator has been developed.Multiline seeder is under development

Stage 1: Oscillator laser 1Single line, Pedestal FreeOutput Power :0.6WRepetition Rate :10Hz,Pulse duration ：25ns

Multiline Oscillation Pulse InjectionStage 2: Oscillator laser 2 Subsystem performance proven.

Single line, Pedestal FreeOutput Power :>120WRepetition Rate :100kHz,Pulse duration ：15~18ns

Stage 3: Oscillator laser 3 Subsystem is under development.Multi- line, Pedestal FreeOutput Power :>100WRepetition Rate :100kHz,Pulse duration ：15~18ns


CO2 Laser amplifier characteristics measurement

Pre amp Pre amp/Main amp

Amplification characteristics have been investigated.

Experimental setup

0.0

0.2

0.4

0.6

0.8

1.0

1.2

0 50 100 150 200Time [μs]

Nor

mal

ized

Inte

nsity

[arb

. Uni

ts]

10μs

Amplified pulse train (100kHz)1. Small signal gain (g0) measurement.2. Amplification characteristics measurement.

(Saturation intensity Es)


- 1 0 1 2 3 4- 10

0

10

20

30

40

50

Pea

k P

ower

(kW

)

T im e(μs)

0 t o r r 3 t o r r

Saturable Absorber

Pedestal controlPedestal control

0.0

0.2

0.4

0.6

0.8

1.0

1.2

0 0.05 0.1 0.15 0.2 0.25 0.3Time [0s]

Inte

nsity

[arb

. Uni

ts]

With P-CellWithout P-Cell

Pockels Cell

0

0.2

0.4

0.6

0.8

1

1.2

0.00 0.05 0.10 0.15Time [μs]

Inte

nsity

[Arb

. Uni

ts]

Inout

Amplification with and without a pedestalwith pedestal without pedestal

Pedestal control by pockels cell and saturable absorber

No pedestal observed


Amplifier Exit（without pumping）

Amplifier Exit（withCW pumping）

Beam Profile without and with RF pumpingBeam Profile without and with RF pumping

No beam quality degradation observed






OutlineOutline


5μs

200μm

Moving

Stationary

Irradiateddroplet

DropletsVelocity :20m/sFrequency:100kHzInterval :202μm

Irradiation Interval

〈600μm 〉

15μs

Required speedRequired speed•• Droplet distance : > 600Droplet distance : > 600μμmm•• Driver laser frequency : 100kHzDriver laser frequency : 100kHz

Requirement of droplet speedRequirement of droplet speed: > 60m/s: > 60m/s

Required pressureRequired pressure (Bernoulli):(Bernoulli):

・・ Xe Pressure : > 5.4MPaXe Pressure : > 5.4MPa

V : velocity⊿P:Pressure

ρ :DensityρPΔ

=2v

Xe droplet technologyXe droplet technology


0

50

100

150

200

250

0 10 20 30 40 50 60 70 80

Pressure (MPa)

Velo

city

(m/s

)

Xe pressurization system has been installed.Xe pressurization system has been installed.Optimization for stable droplet generation is in operation.Optimization for stable droplet generation is in operation.

Xe Pressure : 70 MPa (max.)Xe Pressure : 70 MPa (max.)Demonstrated droplet speed: >100m/sDemonstrated droplet speed: >100m/s

High speed Xe droplet developmentHigh speed Xe droplet development

Xe@170Kρ:2905kg/m3


High repetition rate droplet target operationHigh repetition rate droplet target operation

Fluid: WaterNozzle Dia.:20μmFreq.:1.85MHzλ/d:2.54

Droplet Dia.:33μmSpacing:49.5μmVelocity:94m/s

1. 1. Required droplet frequencyRequired droplet frequencyDroplet Droplet

DiameterDiameter：：DDNozzle Nozzle

Diameter :dDiameter :dTarget Target

VelocityVelocity：：VVFrequencyFrequency：：

ｆｆ

20mm20mm 10mm10mm 100m/s100m/s 2MHz2MHz

Continuous-Jet Method λ/d:5.0 λ=V/f

32

23

fVdD =

MHz frequency droplet generation is required MHz frequency droplet generation is required for high speed (for high speed (100 m/s) 100 m/s) target supply.target supply.

2. High frequency water droplet generation experiment2. High frequency water droplet generation experiment

5MPaAir

Water Tank

Filter

CCDCCDLED

Controller

Amp.Φ20μm Nozzle




HighHigh--powerpower COCO22 laserlaserXe droplet targetXe droplet targetMagnetic field ion mitigation Magnetic field ion mitigation

Latest result andLatest result and summarysummary

OutlineOutline


Fast ion mitigation by magnetic fieldFast ion mitigation by magnetic field

Electromagnet

Nozzle

50mm

VacuumChamber

Mirror

Laser

B

EUV

Xe Jet Nozzle

Ion

Principle: Experimental Set-Up:

0 T 0.6 T

Visible plasma emission:

• Efficient Ion mitigation by magnetic field has been verified


0

200

400

600

800

1000

1200

1400

1600

1800

0 200 400 600 800 1000Delay Time (ns)

Pea

k E

nerg

y (e

V)

0.0E+00

5.0E-09

1.0E-08

1.5E-08

2.0E-08

2.5E-08

3.0E-08

EU

V E

nerg

y (a

rb. u

nit)

Result:The peak Ion kinetic energy decreases with delay time for the CO2 EUV system. For the 10W EUV system a collector mirror lifetime of more than 5 Bpls is therefore expected.

Xe ion energy Xe ion energy dependencedependence on on delay timedelay time

Peak Kinetic Ion Energy EUV Energy

Ion Energy measurement:Time of Flight Method (TOF)

Laser EnergyPre-Pulse (Nd:YAG Laser ): 5mJMain-Pulse(CO2 Laser): 65mJ






OutlineOutline


0

0.2

0.4

0.6

0.8

1

1.2

0 0.2 0.4 0.6 0.8 1 1.2De lay Time (μs)

EUV

(a.u

.)

Drople tJET

Droplet :φ40μmJet :φ30μm

EUV from Xe droplet with preEUV from Xe droplet with pre--pulsed COpulsed CO22 laserlaser

between pre-pulse and CO2 laser

Pre-pulse: 5mJ Nd:YAGMain Pulse: 60mJ CO2

(Pulse width 25 ns)

Optimum delay: 200nsMax Conversion Efficiency: 0.4%

(under optimization)


Preliminary result of 10W EUV SystemPreliminary result of 10W EUV System

CO2LaserType

Stage LaserLine

Pulse Energy[mJ]

PulseWidth[ns]

RepetitionRate [Hz]

LaserPower[W]

CE

[%]

EUV Energyat Source[μJ/pulse]

EUV Powerat IF [W]

TEA - Single 200 100 1800 360 0.4 778 0.4Stage 1: Pre-Test Single 60 25 10 0.6 0.4 240 0.0007 Stage 2 Single 40 15 100000 4000 0.5 200 5.6 Stage 3 Final Multi 70 15 100000 7000 0.5 360 >10

RF

Pre-Test Result with RF CO2 laser Result: Pre-test of EUV LPP system demonstrates feasibility of final 10W target.

0

50

100

150200

250

300

350

0 20 40 60 80 100

Puse Shots Number

EUV

Ene

rgy

[mic

ro J

oul

e]


SummarySummary

1. New RF-CO2 laser based 10-W LPP system is under construction. We are testing sub unit level performances.

Stable 100kHz, 120W oscillator operation has been demonstrated. Multi-line oscillator is also under development. High power amplifier system is under integration. Amplification with low repetition rate experiment shows feasibility of 7 kW laser system. High speed Xenon droplet target has been demonstrated. Preliminary test proved 1.8MHz droplet operation (speed 100 m/s).Current conversion efficiency of droplet target is 0.4%; CE under optimization.Expected lifetime of the collector mirror is > 5 billion pulses with magnetic mitigation.

2. Pre-test of 10W EUV system demonstrates promising feasibility of the final target of 10W(@I/F).

3. Full system demonstration is scheduled for 1Q/2006.

Documents

Development of CO2 Laser Produced Xe Plasma EUV Light ...euvlsymposium.lbl.gov/pdf/2005/pres/13 1-IN-11 Mizoguchi.pdf · High-power CO2 laser Xe droplet target Magnetic field ion