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Core Technology Center

July 12, 2011

NGL Workshop 2011 Katsuhiko Murakami

Katsuhiko Murakami

Lens Engineering Development Department,Production Technology Headquarters

Development of EUV lithographytool technology at Nikon

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July 12, 2011 2NGL Workshop 2011 Katsuhiko Murakami

Outline

Lithography roadmap

Performance of EUV1

Evaluation of flare Ultimate resolution

Contamination control

Developments toward HVM EUV exposure tools Optical design of projection optics

On-body wavefront control

Summary

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Outline

Lithography roadmap

Performance of EUV1





Summary

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K1 factor of ArF immersion and EUV

DRAM hp 32 28 25 22 20 18 16 14 13 11 10 9 8

ArFI

193

nm

1.30 0.21 0.19 0.170 0.152 0.135 0.120 0.107 0.095 0.085

1.35 0.22 0.20 0.175 0.157 0.140 0.125 0.111 0.099 0.088

1.40 0.23 0.21 0.183 0.163 0.145 0.130 0.115 0.103 0.092 0.082

1.44 0.24 0.21 0.188 0.168 0.150 0.133 0.119 0.106 0.094 0.084

EUVL

13.5

nm

0.25 0.59 0.52 0.47 0.42 0.37 0.33 0.29 0.26 0.23 0.21 0.19 0.17 0.150.32 0.75 0.67 0.60 0.53 0.48 0.42 0.38 0.34 0.30 0.27 0.24 0.21 0.19

0.35 0.82 0.73 0.65 0.58 0.52 0.46 0.41 0.37 0.33 0.29 0.26 0.23 0.21

0.40 0.94 0.84 0.75 0.67 0.59 0.53 0.47 0.42 0.37 0.33 0.30 0.26 0.24

0.45 0.94 0.84 0.75 0.67 0.60 0.53 0.47 0.42 0.38 0.33 0.30 0.27

0.50 0.94 0.83 0.74 0.66 0.59 0.52 0.47 0.42 0.37 0.33 0.29

NA

22nm hp 16nm hp 16nm hp 11nm hp11nm hp 8nm hp

32nm hp 22nm hp

ArF immersion will cover 22nm-hp node with double patterning.

EUV with NA0.32 - 0.35 can cover 16nm-hp node. Single generation?

EUV with NA>0.4 can cover 11nm-hp node. Multiple generation

Our target

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Outline

Lithography roadmap

Performance of EUV1





Summary

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22 mm26 mm

WFE: 0.4 nm RMS (average)

Min. 0.3nm RMS ~ Max. 0.5nm RMS

EUV1 PO: WFE and Flare Performance

8% / 8.3%6%EUV1 PO#215% / 16%10%EUV1 PO#1

Kirk flareestimate/measure)

Flare

2 m Kirk pattern in bright field

Optics performance of EUV1

PO#2 has improved WFE and flare than PO#1. NA=0.25

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MSFR(pmRMS) HSFR(pmRMS)

PO#1 100~140 70~130

PO#2 70~130 70~120

2010 51 50

Further improvement of MSFR, HSFRLower flare, Higher reflectivity

Improvement of mirror polishing technology

Nikons optics fabrication technology satisfies EUV HVM requirements.

0%

5%

10%

K

irkFlare

Kirk flare (2um sq/static)

EUV1PO#2

Expectationfor EUV1

best mirror

HVM POExpectation forcurrent bestmirror

8.3%

3.4%2.6%

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Courtesy of Intel

Tar g et 2 8 n m 2 6 n m 2 4 n m 2 3 n m 2 2 n m 2 1 n m

Tar g et 2 0 n m 1 9 n m 1 8 n m 1 7 n m 1 6 n m

Modu lat i on dow n t o 1 6nm HP i s ev i den t , how ever , u l t im a te reso lu t i on i sexpected l y l im i t ed by resi st pe r f o rm ance .

Modu lat i on dow n t o 1 6nm HP i s ev i den t , how ever , u l t im a te reso lu t i on i s

expected l y l im i t ed by resi st pe r f o rm ance .

Target 25nm 24nm 23nm 22nm 21nm 20nm 19nm

Dipole

Dipole

Reference

Conv0.3

Conv0.3

Ultimate resolution with phase shift mask

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Contamination study using a synchrotron facility

Branch chamber

Exposure chamber

Folding mirror

Gate valve with Zr filter

Neutral density filter

Neutral density filter

Rotational photo diode

Sample stage

Load rock chamber

Transfer rod Gas inlet

Synchrotron radiation

0.8

0.85

0.9

0.95

1

0 200 400 600Cumulative dose [J/mm

2]

Relativereflectanc

0.88

0.9

0.92

0.94

0.96

0.98

1

0 2 4 6 8 10Cumulative dose [J/mm

2]

Relativereflectanc

8W/cm21W/cm2

0.1W/cm2

8W/cm2

1W/cm2

0.1W/cm2

0.01W/cm2

0.002W/cm2

0.8

0.85

0.9

0.95

1

0 200 400 600Cumulative dose [J/mm

2]

Relativereflectanc

0.88

0.9

0.92

0.94

0.96

0.98

1

0 2 4 6 8 10Cumulative dose [J/mm

2]

Relativereflectanc

8W/cm21W/cm2

0.1W/cm2

8W/cm2

1W/cm2

0.1W/cm2

0.01W/cm2

0.002W/cm2

Contamination growth with perfluorohexane (C6F14)

BL 18 at SAGA LS SR facility

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1E-5

1E-4

1E-3

1E-2

1E-1

1 10 100 1000 10000 mW/cm2

nm/s

C6F14 (5e-5 Pa)

FC3283 (5e-5 Pa)

C10H22 (5e-5 Pa) (2e-2 Pa)

Cleaning

Contamination

Carbon contamination modeling

Cleaning

Contaminant

ln E EUV intensity [mW/cm2]

Dominantcontamination

Dominantcleaning

Carbon contamination growth rateand cleaning rate with O2 + EUV

Growth/

Cleaningrate[nm/s]

EUV intensity [mW/cm2]

Contamination modeling

ln

V

Grow

th/Cleaningra

te[nm/s]

Modeling

Details were presented by M. Shiraishi in the previous session as A simple modeling of carbon contamination

on EUV exposure tools based on contamination experiments with synchrotron source.

Contamination/cleaning modeling was established using data obtained

from experiments in SAGA LS.

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Suppression of carbon contamination

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

NumberofpulsesirradiatedtoIU[billionpulses]

EUVpow

er[arb.unit

(log)]

Modeled

Actual

Source maintenanceReplace partialIU mirror

Replace partialIU mirror

Cleaning partialIU mirror

Replace / cleaningpartial IU mirror

Source maintenanceClaning partialIU mirror

Modeling, Actual Optimization ofO2 cleaning

Sourcemaintenance

Sourcemaintenance

EUV intensity on reticle

After the optimization of O2 in-situ cleaning,

rapid degradation of EUV intensity was not observed.

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Suppression of carbon contamination

Transmittance of illumination optics

After the optimization of O2

in-situ cleaning, transmittance of illumination

optics was improved, and didnt show further degradation.

7 8 9 10 11 12 13 14 15 16


IUtran

smittance[arb

.unit]

Modeled

Actual

MirrorCleaning

Oxygenop

timization

NumberofpulsesirradiatedintoIU[billionpulses]

IUtrans

mittance[arb.unit]

7 8 9 10 11 12 13 14 15 16


IUtran

smittance[arb

.unit]

Modeled

Actual

MirrorCleaning

Oxygenop

timization

NumberofpulsesirradiatedintoIU[billionpulses]

IUtrans

mittance[arb.unit]

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Outline

Lithography roadmap

Performance of EUV1





Summary

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Imaging simulation

Simulation conditions: Aerial image simulation; Dipole (R=0.2), delta CD +/-10% of CD, Mask CD error +/-3% of CD, Mask contrast 1:100, Flare 5%, TIS

10%, EL+/-2%

16nm hp, Conv.16nm hp, Conv.

11 nm hp, Conv.11 nm hp, Conv. 14nm hp, Conv.14nm hp, Conv.

Conventional illumination

Difficult to achieve sufficient process

window with conventional illumination

below 16nm hp.

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Imaging simulation

Simulation conditions: Aerial image simulation; Dipole (R=0.2), delta CD +/-10% of CD, Mask CD error +/-3% of CD, Mask contrast 1:100, Flare 5%, TIS

10%, EL+/-2%

16nm hp, Dipole16nm hp, Dipole

11 nm hp, Dipole11 nm hp, Dipole 14nm hp, Dipole14nm hp, Dipole

D

Dipole=0.2

Dipole illumination

16nm hp can be achieved with NA>0.3

and off-axis illumination.

NA>=0.4 with OAI will be necessary for11nm hp.

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NA>0.4 Optics Design Update

3 types of projection optics design are under investigation

0.30 0.40 0.50

6 mirror

NA

8 mirror

6 mirror

with C.O.

NA0.4X

NA0.4X

NA0.35EUV1

NA0.4X

PO trans. 5.9%Wave front 3mC.O. Radius 35.4%

PO trans. 1.6%

Wave front 2.9m

340W for 100wph

PO trans. 4.6%Wave front 11m

120W for 100wphPO trans. 4%Wave front 33m

Wave front

Design with central obscuration (CO) has advantage to increase NA.

However, impact on imaging should be considered.

0

0.2

0.40.6

0.8

1

1.2

0 20 40 60 80 100

hp (nm)

Con

trast

Obscuration No Obscuration

Conventional illumination

0

0.2

0.4

0.6

0.8

1

1.2

0 20 40 60 80 100

hp (nm)

Contrast

Obscurat ion No Obscurat ionDipole illumination

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NA>0.4 optics design update

6 mirror system: Relatively large WFE

6 mirror system w/co: Low WFE, high transmittance, impact of central obscuration

8 mirror system: Low WFE, low transmittance, need high-power EUV source

0

0.5

1

1.5

2

WFE Flare Photon loss

Relativepreformance

6-mirror system (NA0.25; EUV1)

6-mirror system (NA0.35)

6-mirror system (NA0.4X)

6-mirror system (NA0.4X, w/co)

8-mirror system (NA0.4X)

Photon loss = 1/transmittance

Nikon investigation of the optimal high-NA PO design continues.

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EUV wavefront metrology system (EWMS)

using New Subaru synchrotron source at University of Hyogo

PDI

1.79 nm RMS

DTI

1.32 nm RMS

8.21 nm

-4.83 nm

PDI

1.79 nm RMS

PDI

1.79 nm RMS

DTI

1.32 nm RMS

DTI

1.32 nm RMS

8.21 nm

-4.83 nm

8.21 nm

-4.83 nm

Difference: 1.08 nm RMS (Z5 - Z36)

0.37 nm RMS (Z7 - Z36)

Digital Talbot interferometer (DTI) and point diffraction interferometer (PDI) using

high-brightness EUV source were developed in collaboration with Canon.

They showed good accuracy in the measurement of 6-mirror projection optics.

Supported by NEDO

Illuminator

Beam line

Vacuum chambers

Vacuum pumps

Optics Loader

Actinic wavefront metrology using SR

Actinic wavefront metrology was established.

However, it required synchrotron source.

P i i l f lti i h t

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(2) Multi pinhole# of pinhole : 1000 (3) Multi pinhole group# of pinhole : 106(1)Single pinhole# of pinhole : 1

MISTI

grating pitch

interval ofpinhole groups

Periodical arrangement of pinhole groups makesfringe intensity 106 times brighter than that in a

single pinhole interferometer.

Each interferogram issuperimposed when

DG = M x DRDG

DR

Grating

CCD

Pinhole

Testoptics

Principle of multi-incoherent sourceTalbot interferometer (MISTI)

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Multi-incoherent source Talbot interferometer (MISTI)

Interferogram

Measured wavefront

Repeatability: 0.02nmRMS

Accuracy: 0.25nmRMS

Experimental setup of MISTI using2-mirror projection optics (HiNA-3)

Improved DTI method was developed so that low-brightness EUV source can beapplied in collaboration with Canon and Univ. of Electro-Communications .

Its good accuracy was demonstrated using 2-mirror projection optics.

This method can be applied to on-body wavefront metrology of EUV exposure tools.

Demonstration of MISTI

Actinic wavefront metrology using low-brightness source was established.

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Application of MISTI to EUV1

Repeatability of wavefront metrology

1st measurement 2nd measurement

MISTI was applied to EUV1

as on-body wavefront metrology.

Repeatability was 0.035nmRMS

Wavefront controllability

Measuredwavefront change

Predictedwavefront change

Wavefront was intentionally changed using

active mirror control system of PO.

Measured wavefront change: 0.378nmRMSPredicted wavefront change: 0.369nmRMS

Difference: 0.041nmRMS

Excellent controllability of wavefront

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Application of MISTI to EUV1

PO was adjusted based on the measuredwavefront with MISTI.

After the adjustment, the measured wavefront

was in good agreement with predicted

wavefront.

C1

C2

C3RCLC

R2

R3L3

R1

L2

L1

On-body wavefront fine adjustment Field

Measured point

L1 L2 L3 LC C1 C2 C3 RC R1 R2 R3

Before adjustment

After adjustmentPredicted

Wavefronterror[Arb.unit]

Position in the exposure field

In good agreement

On-body fine tuning of PO wavefront is now available.

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Summary

Lithography roadmap

Target of EUVL is 16-11nm hp node with NA>0.4.

Performance of EUV1

Flare impact on imaging was confirmed.

Modulation of 16nmL/S was observed using PSM.

Carbon contamination has been successfully suppressed.

Progress towards HVM EUV exposure tools

Significant progress in Optical design of PO with NA >0.4, with

verification continuing.

New actinic wavefront metrology scheme MISTI was developed and

capabilities confirmed.

Successful on-body wavefront control using MISTI has been verified.

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Acknowledgments

EUVA

NEDO

METI

Selete

Intel

SAGA Light Source

Canon

University of Hyogo

University of Electro-Communications

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O 22 Murakami

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