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High Brightness EUV Light Source System Development for Actinic Mask Metrology

Peter Choi, Sergey V. Zakharov, Raul Aliaga-Rossel, Aldrice Bakouboula, Otman Benali, Philippe Bove, Michèle Cau,

Grainne Duffy, Carlo Fanara, Wafa Kezzar, Blair Lebert, Keith Powell, Ouassima Sarroukh, Luc Tantart,

Clement Zaepffel, Vasily S. Zakharov, Alan Michette*, Edmund Wyndham**

NANO‐UV sasEPPRA sas

* Dept of Physics, King’s College, London, UK** Pontificia Universidad Catolica de Chile

COPYRIGHT 2010 NANO‐UV

2010 International

Workshop on EUV

Lithography June 21-25

Maui, HI, USA

2

OUTLINE

• Remaining focus areas for EUVL deployment

• Plasma radiation sources for mask inspection

• Multiplexed source for high power & brightness• Nano-UV: EUV and soft X-ray source unit

– source characteristics– charge energy scan in comparison with predictions

• Multiplexed high brightness EUV sources – HYDRA4 ABI– HYDRA12 AIMS– HYDRA - APMI


2010 International

Workshop on EUV


Maui, HI, USA

3

EUV (13.5nm wavelength) lithographychosen for nano features microchip production

HP

EUV source for HVM & actinic mask inspection- a key challenge facing the industry

NOWEUV for

22 nm HVM


2010 International

Workshop on EUV


Maui, HI, USA

4

Remaining Focus Areas

- light source for Litho and mask inspection critical -

EUVL Symposium, Tahoe 2008 EUVL Symposium, Prague 2009

1 - Long-term source operation with 100 W at the IF and 5 megajoule per day

2 - Availability of defect-free masks, throughout a mask lifecycle, and the need to address critical mask infrastructure tool gaps, specifically in the defect inspection and defect review area

3 - …

1 - Mask yield & defect inspection/review infrastructure

2 - Long-term source operation with 115 W at the IF for 5mJ/cm2 resist sensitivity or with 200W at the IF for 10mJ/cm2 resist sensitivity

3 - …


2010 International

Workshop on EUV


Maui, HI, USA

5

Actinic Mask Inspection - key source requirements based on current studies

‐High‐brightness, small‐etendue, high‐repetition‐rate, and clean light source is preferable

Source Workshop 2009 Baltimore


2010 International

Workshop on EUV


Maui, HI, USA

6

10-5

10-4

10-3

10-2

10-1

100

101

102

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

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

Mass Depth (rho*r), g/cm2

Multiplexing- a solution for high power & brightness

- compct physical size of SoCoMo ?

Z* Scan

tin• Small size sources, with low enough etendue

E1=AsΩ << 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 ⋅⋅Ω⋅⋅∝ τ

• 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


2010 International

Workshop on EUV


Maui, HI, USA

7

Nano-UV: Current Product Development

• Generic Source Products– high brightness unit source - CYCLOPS™ -B– high brightness multiplexed source - HYDRA™ -B– high power multiplexed source - HYDRA™ -P

• Research Metrology Products– Nano-patterning Resists Exposure Tool - GeNI™– Soft X-ray In Vitro Microscope - McXI™– EUV Mask Inspection Microscope - McEUVI™


2010 International

Workshop on EUV


Maui, HI, USA

8

DischargeVoltage

EUV diode

Spot-scan spatial profile ⇒

Nano-UV: High Brightness EUV Sourcemicro-plasma pulsed capillary discharge

GEN-II CYCLOPS™ cellsTypical Operating Conditions & Measured Performance

• use SXUV20 Mo/Si filtered diode (IRD)• 3 nm EUV band (12.4 nm -15.4 nm)• (110 nm) Al on Si3N4 (50 nm) to reject OoB• discharge in He/Ar & He/Ar/Xe admixture• electrical stored energy 0.2-0.4 J• 21 - 25 kv, 1-3 kHz operation• radiation pulse < 40 ns• irradiance measured at different distances • EUV power at beam spot - > 3 W at 1 kHz• plasma can be optimized for high power or high

irradiance• typical etendue 5.10-3 to 1.10-2 mm2.sr

0 5 10 15 20 25 30 35 40 450

100

200

300

400

500

600

Data: Data1_MaxpulseModel: Gauss Chi^2/DoF = 570.50661R^2 = 0.97744 y0 9.64813 ±4.68332xc 21.54925 ±0.11167w 8.27341 ±0.25284A 4791.85297 ±152.17737

Maxpulse B

Pho

todi

ode

sign

al (m

V)

Distance (mm)

V=25.4kV ( 1.24nF)HIGH POWER

ModeIrradiance

3.5 W/cm2 at 50 cm from

plasma sourceDelivered

Power is 3.9 W over a 16 mm spot @ 1 kHz


2010 International

Workshop on EUV


Maui, HI, USA

9

Source Characteristics I- irradiance vs stored energy• Measurement parameters

- Average mode over 128 shots:- 1.6mm diameter capillary- working pressure P =20mtorr- He:Ar:Xe mixture- distance between diode and the

capillary=50cm- operating frequency = 1 kHz- diode quantum efficiency @ 13.5nm=1.4e/ph- diode filter transmission band = 3nm

(12.4-15.4nm)

0.18 0.20 0.22 0.24 0.26 0.28 0.30 0.320.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

Irr

adia

nce

at th

e pr

ofile

max

imum

(x

10e

17 p

h/cm

2/s)

Stored energy (J)

0

50

100

150

200

250

0 100 200 300 400 500

In-b

and

EUV

ener

gy p

er s

hot,

mJ

Stored energy, mJ

EU

V e

nerg

y pe

r sho

t, μ

J

Energy scan calculated

(in 2% band)

Energy scan experiment

(in 3nm band)


2010 International

Workshop on EUV


Maui, HI, USA

10

Source Characteristics II- etendue and power• Optimization Measurements

- filtered IRD diodes on translation stages at 3 axial positions from the radiation source

- transverse scan to obtain radiation profile and irradiance

- Gaussian envelope fit to calculate power- use 1/e2 beam spot diameter measured and

beam expansion angle to estimate etendue- 21 kV operation at 1 kHz, He-Ar admixture- at 62 cm

75cmCyclops

1

32

0 5 10 15 20 25 30 35 40 45 500.0

0.5

1.0

1.5

2.0

2.5

3.0

Data: A62cm_MaxpulseModel: Gauss Chi^2/DoF = 21388.44238R^2 = 0.95841 y0 -11.405±33.02329xc 30.71325 ±0.12772w 4.98339 ±0.25861A 15674.94487 ±809.61347

Maxpulse B

Pho

todi

ode

sign

al (V

)

Distance (mm)

FWHM 5.8mm

Diode signal at peak

400 450 500 550 600 650 700 750 800 8500

1

2

3

4

5

6

beam expansion Half angle =0.30°solid angle= 8.8e-5 sr

HWHM linear fit

Rad

ial d

ista

nce

(mm

)

Axial distance from the capillary (mm)-200 0 200 400 600

0.0

0.5

1.0

1.5

2.0

2.5

Average over 128 shotsV

break=21kV

@ 62 cm from source35mtorr (He:Ar)int(V(t)dt)= 127nVsτ=54nsNph=4.36 e17 ph/cm2/s

Phot

odio

de s

igna

l (V)

Time (ns)

Scanned signal profile HWHM obtained at 3 locations⇒ ⇒

• peak irradiance = 6.4 W/cm2

• power in spot = 2.2 W• beam FWHM = 5.8 mm• etendue < 7 E-3 mm2.sr (max)

radiation(3nm band)


2010 International

Workshop on EUV


Maui, HI, USA

11

Source Characteristics III- wavefront measurement

• EUV beam diameter d= 9.75 mm at R=1890 mm from source

• Beam divergence half angle 0.19°• Solid angle: Ω = 0.0345 msr

Derived wavefront166 nm RMS (12 λ) &

760nm PV (58 λ)

HASO™ X‐EUV Shack Hartmann wavefront sensor ‐ (manufactured by Imagine Optic)

1890 mm

HASO™EUV source

* With support of G. Dovillaire, E. Lavergne from Imagine Optic and P. Mercere, M.Idir from SOLEIL Synchrotron

Acquired image60s exposure,

source at 1 kHz

(peak to valley)

(root-mean-square deviation)


2010 International

Workshop on EUV


Maui, HI, USA

12

20 21 22 23 24 250.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

02-03-2010 03-03-2010

Pho

todi

ode

sign

al (V

)

Discharge voltage (kV)

EUV Source Product GEN II emission characteristic stability test

The emission-voltage discharge characteristic enables one to correct the radiation output level and to control the dose stability


2010 International

Workshop on EUV


Maui, HI, USA

13

HYDRA™-ABI - spatial multiplexing for blank inspection

• Design Specifications– 60 W/mm2.sr in‐band 2% EUV radiant brightness at the IF

– 0.6 W at the IF– etendue 10‐2 mm2.sr– source area ‐ 31 mm2 / TBD– optimized for mask blank inspection– 4x i‐SoCoMo™ units working at 3 kHz each

– no debris / membrane filter– close packed pupil fill

• Current Status– 4 units integration & characterization– single unit optimization– ML mirrors evaluation & modelling


2010 International

Workshop on EUV


Maui, HI, USA

14

HYDRA4-ABI™

- pupil arrangements

Source 1 only Source 2 only

Source 4 only Source 3 only

Each source turned on separately and aligned to a different corner

• Radiation observed on a fluorescent screen 70 cm downstream

ALL 4 Sources

All 4 sources aligned to a pointwithout use of any solid optical collector

25 mm


2010 International

Workshop on EUV


Maui, HI, USA

15

• Design Specifications – 100 W/mm2.sr in‐band 2% EUV brightness– 2.4W at the IF– etendue ‐ 2.4 10‐2 mm2.sr (50% fill pupil)– source area ‐ 4 mm2 / variable σ– optimized for aerial image measurements– 12x i‐SoCoMo™ units, 5 kHz working each– no debris / membrane filter– variable pupil fill and σ

• Current Status– system characterization– single unit optimization– ML mirrors modelling

curved ML

plane ML

HYDRA™-AIMS- spatial multiplexing with variable σ


2010 International

Workshop on EUV


Maui, HI, USA

16

HYDRA12-AIMS™

- prototype system

A EUV Source for Mask Metrology

• 2 Cells operation simultaneously @ 20KV ; 1 KHz Operation• Alignment on SUXV 5 Photodiode • Intentionally off axis Cell 1

Photodiode

Pulse discharge

By intentionally off axis the beam light of cell 1 No impact on the Beam Light of Cell2

Multiplexing sources Choice is proven as agile approach to reduce cost

The Cross Talk Test


2010 International

Workshop on EUV


Maui, HI, USA

18

HYDRA™-APMI - unique temporal & spatial multiplexing

• Design Specifications – 1200 W/mm2.sr in‐band EUV radiant brightness– 2.4 W at the IF– etendue ‐ 2. 10‐3 mm2.sr– source area ‐ 20 mm2

– optimized for patterned mask inspection– 8x i‐SoCoMo™ units working at 3 kHz each– 24 kHz temporally multiplexed– no debris / membrane filter– Gaussian output spot

• Current Status– optics design & modelling– single unit optimization– mechanical design


2010 International

Workshop on EUV


Maui, HI, USA

19

HYDRA™- metrology sources - ROADMAP


2010 International

Workshop on EUV


Maui, HI, USA

20

• Collaborators – 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–

• Sponsors– EU & French Government– ANR- EUVIL– OSEO-ANVAR

• RAKIA

• EUV LITHO, Inc.

Acknowledgements


2010 International

Workshop on EUV


Maui, HI, USA

21

A New Technical Capability Arising

HYDRA™

– Ultra high brightness– modular construction– small foot print– low cost of ownership– adaptable to user needs

high brightness euv light source system development for ... · high brightness euv light source...

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