Multilayer optics with spectralMultilayer optics with spectralpurity enhancing layers for thepurity enhancing layers for the

EUV wavelength rangeEUV wavelength range

R. van de KruijsR. van de Kruijs11, A. Yakshin, A. Yakshin11, M.M.J.W. van Herpen, M.M.J.W. van Herpen33, D.J.W. Klunder, D.J.W. Klunder33, E. Louis, E. Louis11, S. Alonso van der Westen, S. Alonso van der Westen11,,

H. EnkischH. Enkisch22, and S. Müllender, and S. Müllender22,, L. Bakker L. Bakker33, V. Banine, V. Banine44, M. Richter, M. Richter55 and F. Bijkerk and F. Bijkerk11

11FOM Rijnhuizen, PO Box 1207, 3430 BE Nieuwegein, The Netherlands, www.rijnh.nlFOM Rijnhuizen, PO Box 1207, 3430 BE Nieuwegein, The Netherlands, www.rijnh.nl22Carl Zeiss SMT AG, Oberkochen, GermanyCarl Zeiss SMT AG, Oberkochen, Germany

33Philips Research Laboratories, Eindhoven, The NetherlandsPhilips Research Laboratories, Eindhoven, The Netherlands44ASML, Veldhoven, The NetherlandsASML, Veldhoven, The Netherlands

55 PTB, Berlin, Germany PTB, Berlin, Germany

Fred Bijkerk, FOM, 4thEUVL Symp/SWS, Nov 2005 San Diego 2

FOMFOMFOMFOMOoB status: statements 4thEUV Symposium

• Vadim Banine (ASML)– OoB: ‘very uncertain thing’

• Jeroen Jonkers (Philips Extreme UV)– OoB 130-250nm: 48% of in-band,

reduces to 18% when consideringproper etendue

• Yusuke Teramoto (EUVA/USHIO)– 140-325nm: 21.7% of in-band

(Xe, FC data), reduces to 13.7%at IF (120-400nm)

• Martin Richardson (UCF)– Less threat in the VIS using Sn

• Björn Hanson (CYMER)– >130nm: <15% of in-band

0.00

0.10

0.20

0.30

0.40

0.50

0.60

13.5

+/- 2

%

160-7

15

715-8

50

850-2

200

lase

r co

ntributio

n

wavelengh band (nm)

en

erg

y (

mj

/ 2

pi

sr)

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

no

rma

lis

ed

to

to

tal

en

erg

y

21.7

2.1

0.6

0 10 20 30

140-

325nm

325-

715nm

715-

2000nm

Wa

ve

len

gth

ba

nd

Ratio to in-band [%]

13.7

0.6

0.5

0102030

120-

400nm

400-

750nm

750-

2800nm

Wa

ve

len

gth

ba

nd

Ratio to in-band [%]

Source(Flying circus)

IF(Calorimeter)

Flying Circus OoB source assessments

Fred Bijkerk, FOM, 4thEUVL Symp/SWS, Nov 2005 San Diego 3

FOMFOMFOMFOMRequired OoB levels

Vadim Banine, ASML, this WS

Fred Bijkerk, FOM, 4thEUVL Symp/SWS, Nov 2005 San Diego 4

FOMFOMFOMFOM

OoB set-up of FC• Different filters allow Ross

method for spectral bands (IR,VIS, VUV, …)

– IR transmittance filter RG850#1 &RG715#2, LiF, glass, quartz, etc

• All components broad bandspectrally calibrated

Flying Circus VUV characterization

VUV Reflectometry set-up at the PTB laboratory at BESSY II

M. Richter, U. Kroth, PTB, Berlin

M. Richter, et al, Nucl. Instr. Meth. 467-468, 605-608 (2001)

Fred Bijkerk, FOM, 4thEUVL Symp/SWS, Nov 2005 San Diego 5

FOMFOMFOMFOMEUV/VUV EUV/VUV calibrationcalibration datadata standard MLstandard ML

Mirror calibration Measured data follow IMD simulation in 50-300 nm bandSmall differences with prior data (Bakshi et al, Stuik et al)

Fred Bijkerk, FOM, 4thEUVL Symp/SWS, Nov 2005 San Diego 6

FOMFOMFOMFOMPreambule OoB radiation

• Significant amount of radiation outside EUV band– Plasma emits from collection of (cooler) ionization stages– Strong dependence on source type, driver system, collector module

spectral respons, operating conditions, phase maintenance cycle, …– Standard ML shows broad band VUV reflectivity

• Spectral VUV fraction leads to parasitic resist exposure– 100-200 nm range critical, feedback from resist suppliers reqd

• Amount of suppression needed unknown– Depends on source type, operating conditions, resist type, …

Spectral purity enhancing optical device reqd compatible w optical path & adjustable OoB/EUV attenuation

Fred Bijkerk, FOM, 4thEUVL Symp/SWS, Nov 2005 San Diego 7

FOMFOMFOMFOM

"For this purpose, a new multilayer design was developed that includesspectral purity enhancement (SPE)".

Principle of Spectral Purity Enhanced ML

Spectral purity enhancing layer Option: normal cap layer

Multilayer mirror

Use anti-reflection & absorption properties of SPE layer to suppressunwanted wavelengths

Maarten van Herpen, Dion Klunder, Philips Research

Fred Bijkerk, FOM, 4thEUVL Symp/SWS, Nov 2005 San Diego 8

FOMFOMFOMFOMTheoretical performance SPE-ML

VUV characteristicsdetermined by– Design of stack

• Tradeoff EUV-VUV– Materials properties– Deposition technology

Fred Bijkerk, FOM, 4thEUVL Symp/SWS, Nov 2005 San Diego 9

FOMFOMFOMFOM

Spectral purity enhanced ML:VUV attenuation

VUV suppression of SPE-ML ~ 80%

Characterization of out of band VUV reflectivity First experimental samples VUV reflectometry beamline PTB

Fred Bijkerk, FOM, 4thEUVL Symp/SWS, Nov 2005 San Diego 10

FOMFOMFOMFOM

Spectral purity enhanced ML:EUV reflectivity

Reflectivity loss of SPE-ML at EUV limited to 4.5%

Characterization of in-band EUV reflectivity First experimental samples EUV reflectometry data, PTB

Fred Bijkerk, FOM, 4thEUVL Symp/SWS, Nov 2005 San Diego 11

FOMFOMFOMFOMSummary

• Current sources show ample OoB emission• 1st assessment by Flying Circus: ‘the OoB problem exists’• Refinement by assessing OoB @ IF, include collector characteristics, source operating

conditions, ...

• Resist, thermal & contamination aspects urge substantial OoBsuppression

• New ML-based design of SPE system offers solution• Factor 5 suppression of OoB in critical 100-200nm range (single optic)• Factor 100 suppression when integrated over 100-200 nm range using four elements• Acceptable (4.5 abs%) loss of EUV reflectivity/element• ML-technology based

– Produced using existing, e-beam based, deposition technology– No change of optical path– Flexible attenuation

• Further development on-going• Verification of optical constants in the VUV• Combination of protective and OoB suppressing features to be explored• Heat load & cooling reqts• VIS-IR suppression to be verified

Fred Bijkerk, FOM, 4thEUVL Symp/SWS, Nov 2005 San Diego 12

FOMFOMFOMFOM

1. S. Alonso et al, Technology Transfer report,SEMATECH (2004)www.sematech.org/docubase/abstracts/4490atr.htm

2. R. vd Kruijs et al, Proc ICTF13, Stockholm (2005)3. E. Louis, et al, Proc SPIE 3997 Santa Clara (2000)

406-4114. www.scientec.nl5. M. Richter, et al, Nucl. Instr. Meth. 467-468, 605-608

(2001)

Funding from

AcknowledgementsAcknowledgements