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DPP Source Development Status

panel discussion:

“Reliable High Power EUV Source Technology for HVM: LPP or DPP ? ”

EUVL Workshop, June 10-12, 2008, Maui

J.Kleinschmidt

2008 International Workshop on EUV Lithography, June 10-12, 2008, Maui, HI 2

LPP DPP

Starting point


LPP DPP

We will come back to these argumentswith updated values after the presentation of our DPP development status


We started with 2 approaches• high electrical input pulse energies (> 6J ) at

moderate repetition rates (10 kHz - 20 kHz) based on RDE source Laser Assisted Tin Droplet evaporation (LAD)

• high repetition rates ( > 40 kHz ) at electrical input pulse energies ≤

6J based on RDE source

with Laser Assisted Tin Surface evaporation (LAS)

Status DPP development


Status DPP development laser assisted

Tin droplet evaporation Tin surface evaporation

Tin droplets / diameter : 85 μm , frequency:105 kHz direction of the droplet stream : horizontal

Distance to nozzle: 60 mm

Distance to nozzle: 270 mm

•••

•

dropletbeam

LAD arrangement :droplet on demand andcontinuous droplet injection have been tested


Tin surface evaporationtotal emission

∅

1.3 mm


0

50

100

150

200

250

0 5 10 15 20

input pulse energy / J

EUV

pul

se e

nerg

y / m

J/2

π

Tin droplet evaporationtotal emission∅

1.3 mm

♦♦♦

laser assistedTin droplet evaporation Tin surface evaporation

main results /Tin droplet evaporation :

EUV pulse energy ~ 100 mJ /2π

out of ∅

1 … 1.3 mmoperating modes

- single shot - burst regime

100 pulses , 5 kHz500 W / 2π


Summary

•

Demonstrated intrinsic conversion efficiency ~ 2% for both cases

•

No benefits of LAD concerning the collectable ( ∅

1.3 mm ) EUV pulse energies ( mJ/2π ) for input pulse energy range < 10 J

•

Mass limited Tin injection with LAD is possible but needs droplet diameters < 40 μm for a source with ~ 1000 W/2π inband power and ~ 10 kHz repetition rate, very difficult to realize

•

The LAD arrangement is more complex comparatively because of the Tin droplet generation and injection




Conclusion:Because of the relatively higher complexity, and possibly worse reliability of LAD , we favored LAS

Question:Is the RDE technology with laser assisted Tin surface ( LAS ) evaporation scalable to HVM power level ?




Power scaling of RDE-DPP with LAS

• Higher EUV powers up to HVM ranges can be achieved by

– Increased electrical pulse energy (E)– Increased pulse frequency (f)– Improved conversion efficiency (CE)

• Design of proof-of-principleexperiments using the same basic principle and slightly modified alpha source hardware

Tin bath

capacitor bank

laserVacuum

Tin Film

coolingE

CE

f

1.3 mm ∅


10

Constant CE and collection efficiency

Coll.eff.=70%

34 mJ

1 mm1 mm

82 mJ

Coll.eff.=68%

0 2 4 6 80

1

2

3

4

0

20

40

60

80

100

intri

nsic

CE

[%]

input energy [J]

colle

ctio

n ef

ficie

ncy

[%]

0 2 4 6 80

20

40

60

80

100

outp

ut e

nerg

y [m

J/2π

]

input energy [J]

Power scaling: pulse energy


2008 Workshop on EUV Lithography, June 10-12, 2008, Maui,HI

11

Averaged over 128 measurements

Δt=10 μs (f=100 kHz)

Δt=200 μs (f = 5 kHz)

Coll. eff. = 67%1 mmColl. eff. = 67%

f = 1/Δt time

ΔT fixed Δt variable

Double pulse experiment to mimic high frequency f

Coll. eff. = 65%

0 20 40 60 80 100 1200

1000

2000

3000

4000

outp

ut p

ower

[W/2

π]

frequency [kHz]

0 20 40 60 80 100 1200

20

40

60

80

100

outp

ut e

nerg

y [m

J/2π

]

frequency [kHz]

Power record:3800 W / 2π

Power scaling: frequency Constant CE and collection efficiency




Latest result using liquid tin electrodes 300 pulses at 40 kHz

No accumulation of plasma remnants

Double pulses good mimic for high frequency operation

0 50 100 150 200 250 3000

10

20

300 2 4 6

EU

V [m

J/2π

]

pulse number

time [ms]


13

Status of heat removal capability

• Tin Handling Box (for electrode cooling) for 100kW input power– Improved cooling needed → active tin pumping

– Component release for high reliability

• Debris Mitigation System for 100kW input power– Building on 4 years of Sn DMT experience

– Water cooled → temperatures remain under control

PumpWater Chiller

Heat Transfer

Circulation

Lamp Head

Bath

520 K

700 K

600 K

650 K

550 K

max. 590°C cooling water

Releasing integrated source and SoCoMo at Beta power levels starts 2008




Philips/Xtreme IF power roadmap supporting timely introduction of Beta and HVM

Q4/07 Q4/08 Q4/09 Q4/10 Q4/11 Q4/12 Q4/13

10

100

10

100

EU

V in

band

pow

er a

t IF

(W)

Time

Alpha based

Beta product

500500

HVM product



• Last year’s results:

• New debris mitigation system shows 10Gshot lifetime proven by accelerated lifetime tests on samples

• More resistent collector materials realize additional 6x lifetime increase

0

0,5

1

1,5

2

2,5

3

3,5

4

4,5

5

0 20 40 60 80 100 120Operating hours

EUV

pow

er @

IF (a

lpha

col

lect

or)

/ W

Constant EUV power at intermediate focus !

continuous operation

1 Gshot

=> 60Gshot or half-year lifetime already

+ =

0 5 10 15 20 25 300

20

40

60

80

100

exposed sample reference sample

Ref

lect

ivity

/ %

angle / °


Collector lifetime


Summary

•

Demonstrated intrinsic conversion efficiencies in the range of ~ 2 % up to 6 J input pulse energy

•

cooling capability of important components sufficientfor ~ 100 kW electrical input power ( current status )

•

DPP sources with laser assisted Tin surface evaporation are scalable to HVM power level,

•

4 sr grazing incidence collector feasible

•

proven lifetime of optical samples > 10 Gshot10 Gshot (DPP) corresponds to ~ 200 Gshot (LPP)



• Integrated metrology tools provide for reliable operation with constant source characteristics

• Performance results and improvements benefit from partnering with key component suppliers and feedback received from customers

Status DPP development / integration aspects

XTREME: installed EUV Xe DPP sources in the field• 6 DPP sources in use for wafer exposures• 10 DPP sources operated for EUV research• XTS13-150 IF has been successfully

integrated at customer side

XTS13-75IFXTS13-35 XTS13-150IF


Philips: installed EUV Sn DPP sources in the field

• All sources and SoCoMos running 100% duty cycle• On-site service engineers presence leads to short feedback loops

and continuous improvements on all spec points

• ASML – Veldhoven / Netherlands• IMEC – Leuven / Belgium• CNSE – Albany / USA• 5 operational sources in development

in Aachen / Germany

Albany/Leuve n

Aachen

Status DPP development / integration aspects


LPP DPP

Transmission from plasma to IF

see:remarks onnext page

updated table DPP LPPclaimed

LPPrealistic

coll solid angle / 2π X reflectivity(50%)

0.32 ( 4 sr ) 0.36 ( 5 sr ) 0.36 ( 5 sr )

transmission of Debris tool 0.7 1 ~ 0.5

aperture transmission(Etendue limitation)

0.5 1 ~ 0.7

gas transmission 0.9 0.9 0.9

total transmission 0.1 0.32 ~ 0.11

LPP coll. eff. / DPP coll.eff.

~ 3 ~ 1


solid angle of collector optics•

collector proposals with solid angles up to 4 sr exist for DPP sources

transmission / Debrismitigation scheme•

not clear why LPP (using Sn target) requires no mechanical foil trap

•

our experience with LPP show : this is only possible with Xe•

if a mech. foil trap is needed , it is associated with a significant drop in transmission [ double path (0.7)² ~ 0.5 ]

source size / Etendue limitation•

for optical thickness > 1 and a given plasma temperature the emitted EUV power per 2π

scales with ~ [emitting surface area x duration of emission x repetition rate]

•

there is no fundamental difference between LPP and DPP

LPP DPP

Transmission from plasma to IF


Summary / physical background• Tin plasma densities for CO2 - LPP ( ncrit = 1019 cm-3)

nearly same as for DPP ( 1 … 5 1018 cm-3 )• about same plasma temperature of ~ 35… 40 eV⇒

for optical thickness > 1 and a given plasma temperature the emitted EUV power in 2π

scales with ~ [emitting surface area x duration of emission x repetition rate]

⇒ same EUV power in 2π at same repetition rate will result in same plasma size

• Demonstrated conversion efficiencies for both technologies in the range 2 – 3 %No principal advantage based on physical background for LPP generation of EUV light

LPP DPP


Summary / integration aspects

• DPP sources at the time technically superior ( integrated sources in field , long term operation )

• LPP sources still at the stage of laboratory sources ( no integrated system in the field, short term operation )

• LPP is missing experience in the system engineering and has no long-term advantages over DPP

LPP DPP

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