overview of euv lithography

Overview ofEUV Lithography

David Attwood

University of California, Berkeley

(http://www.coe.berkeley.edu/AST/sxr2009)

07 Overview of EUV Lithography / Spring 2009

Extreme Ultraviolet (EUV) LithographyBased on Multilayer Coated Optics

Reflectivemask

Absorberpattern

Multilayermirror

Wafer to record 30 nm features or smaller, overcm2 dimensions

4:1reductionoptics,aspheric,multilayercoated

λ = 13 nm

6.7 nmperiod

MoSi

Ch10_08_June08.ai

CU_Jan12_04.pptD. Attwood 9

EUV Lithography Will Use aStep and Scan Ring Field System

Ch10_F05_modif.ai

International Technology Roadmapfor Semiconductors†

†Semiconductor Industry Association (SIA), December 2004 update. *Possible 2-year cycle for leading edge companies.

2005* 2007* 2011*2003*

SIA_RdmpTbl_Sept2008.ai

First year of volume production 2004 2007 2010 2013 2016

Technology Generation 90 nm 65 nm 45 nm 32 nm 22 nm(half pitch, 1:1, printed in resist)

Isolated Lines (in resist) 53 nm 35 nm 25 nm 18 nm 13 nm[Physical gate, metalized] [37 nm] [25 nm] [18 nm] [13 nm] [9 nm]

Chip Frequency 2.5 GHz 4.9 GHz 9.5 GHz 19 GHz 36 GHz Transistors per chip (HV) 190 M 390 M 770 M 1.5 B 3.1 B (3 × for HP ; 5 × for ASICs)

DRAM Memory 1.1 G 2.2 G 4.3 G 8.6 G 34 G(bits per chip)

Field Size (mm × mm) 22 × 32 22 × 32 22 × 32 22 × 32 22 × 32

Wafer Size (diameter) 300 mm 300 mm 300 mm 450 mm 450 mm

2009*


The Engineering Test Stand (ETS):A Pre-manufacturing EUV Stepper

Maskstage

Projectionoptics

Waferstage

Collectionoptic

EUV Plasmasource

Condenseroptics

Courtesy of R. Stulen / Sandia

SPIE 2004 Santa Clara, CA / Intro to EUV Lithography 2Attwood/SRI_2006_Korea.ppt

Courtesy of Dr. Hans Meiling, ASML

Professor David AttwoodAST 210/EECS 213Univ. California Berkeley Ch10_powrpt.ppt

Full-field Images Printed on ETS

Using Shipley EUV-11A resist,scan time is ~15 minutes.

32.5 mm

24 mm

200 mm wafer

Courtesy of G. Kubiak, D. Tichenor, and B. Replogle, Sandia National Laboratories.

Professor David AttwoodAST 210/EECS 213Univ. California Berkeley

Diffraction Limited Aspherical Optics AreCritical to the Success of EUV Lithography

Courtesy of John Taylor, LLNL.

• λλλλeuv /50 figure

• Low flare

• Ultrasmooth finish

• 10 µm departure from a sphere

Tinsley Sample CZerodur-M

150 mm diameter

Ch10_DiffrLtdAsph.ppt

Ch10A_2004.ppt

Prof. David AttwoodAST 210/EECS 213Univ. California, Berkeley

N = 40D = 6.7 nm

(Courtesy of Sasa Bajt, LLNL)ˇ

A High Quality Mo/Si Multilayer Mirror


High Reflectivity, Thermally and Environmentally RobustMultilayers Coatings for High Throughput EUV Lithography

Courtesy of Sasa Bajt / LLNLˇ

Professor David AttwoodAST 210/EECS 213Univ. California Berkeley Ch10_powrpt.ppt

An Example of a 0.25 N.A. 6-MirrorEUV System

NA = 0.25

RFW = 2.0 mm

Dist. < 1 nm

RMS = 0.025λ(λ = 13.4)

1390.0 mm

M1

M2

M3

M4

M5

Mask

Wafer

M6

Courtesy of R. Hudyma and D. Sweeney, LLNL.


EUV Source Candidates for Clean, Collectable13-14 nm Wavelength Radiation

Laser Produced Plasma Source Electrical Discharge Plasma Source

Courtesy of Neil Fornaciariand Glenn Kubiak, Sandia.

EUV

Rearelectrode

Frontelectrode

Capillary

Hot, EUVemittingplasma

Xe(1 Torr)

Highvoltage

Ch10A_2004.ppt


Multilayer Mirror Parameters:40 bilayers, σ = 0.5 nm rms, Γ = 0.44, FWHM of curve centered at 13.5nm

0

0.005

0.01

0.015

0.02

0.025

0.03

0.035

0.04

0.045

0.05

8 9 10 11 12 13 14 15 16 17 18 19

Wa ve le ngth (nm )

Ref

lect

ivit

y, In

ten

sity

(au

)

EUV Spectrum of Capillary Discharge Plasmawith Nine Mirror Optical System

(Courtesy of Jason Dimkoff, Sandia)

Measured Xe dischargeplasma spectrum 2.2% spectral bandpass for a

9-mirror, 70% reflectivity, Mo/SiEUV multilayer mirror system

Jason Dimkoff AST 213

Typical EUV spectrum from a Xenon plasmain a capillary electrical discharge

References:Blackburn J, Carroll P, Costello J and O’Sullivan G 1983 J. Opt. Soc. Am. 73 1325Gayasov R and Joshi Y 1998 J. Phys. B 31 L705Kaufman V and Sugar J 1984 J. Opt. Soc. Am. B 1 38Kaufman V, Sugar J, and Tech J 1983 J. Opt. Soc. Am. 73 691Sugar J and Kaufman V 1982 Physica Scripta 26 419O’Sullivan G 1982 J. Phys. B 15 L765

Ch06_Xe_Sn_Spectra.ai

Professor David AttwoodAST 210/EECS 213Univ. California, Berkeley

Comparative Spectra: Xe and Sn

80 0

1

2

3

4

5

0.5

1.5

1

2.5

2

3.5

3

9 10 11 12 13

4p54d9 → 4p64d8

5p → 4d

4p64d7(4f+5p) → 4p64d8

Xe+10

Xenon

• Debris is the issue

Tin

Sn+10

Rel

ativ

e in

tens

ity

14 15 16 17 18 12 13 14 15 16 1817 19 20nmnm

Courtesy of G. O’Sullivan (Univ. College Dublin) R. Faulkner (UCD Ph.D, 1999) A. Cummings (Nahond Univ. Ireland)

Absorberpattern Buffer layer

Capping layer

Substrate:Low thermal expansion material (LTEM)(6" square × 1/4" thick)

Multilayer Coating

Typically

Mo/Si multilayer (d = 6.7 nm)with 30 nm SiO2 capping layer

Cr or TaN absorber (~70 nm)with 50 nm Ru Buffer layer

LTEM substrate(Ti-doped fused silica)ULE (Corning), orZerodur (Schott)

Ch10_ReflecMask.ai

Reflective Mask for EUV Lithography


Ch10A_2004.ppt


Amplitude Defect Phase Defect

Mask Blank Defects Can Be On the SubstrateOr Within the Stack

Ch10A_2004.ppt


EUV Scatter

•

••

•

•

•

•

•

•

•

•

86 nm equiv. defect

100 µm 2797bf.msk

SEM

AFM

Defect mapof mask blank

1µm

Defect Map Allows Correlation of Defects to Other Tools

Ch10_D_powrpt.ppt

Professor David AttwoodAST 210/EECS 213Univ. California Berkeley

At-Wavelength Mask Blank Defect Inspection

• At-wavelength response to phase and opaque defects

• Correlation with conventional inspection tools

50 µm

Dark Field

Courtesy of Moonsuk Yi (LBL) and J. Bokor (UCB/LBL).

45 nm45 nm 40 nm40 nm 35 nm35 nm

35 nm35 nm

Major support and collaborators include Sematech, Intel, AMD, IBM, Samsung and others.

Mask

Wafer

Two-bounce, 0.3 NA, METat ALS Beamline 12.0

Programmable illumination

Annular

Significant issue forEUV lithography

When will EUV resists beavailable with combinedhigh spatial resolution(20 nm), high sensitivity(10 mj/cm2), and low lineedge roughness (LER,1.2 nm)?

22 nm lines and spaces

10mJ/cm2

Courtesy of Patrick Naulleau, CXRO/LBNL.

Addressing critical EUV lithography issues for Sematechat the ALS: testing state-of-the-art EUV resists

Intel EUV MET InstallationIntel EUV MET Installation

Courtesy of Jeanette Roberts, Intel

J. Phys. D: Appl. Phys. (London) 37, 3207(2004)

Ch10_thruputModls_June08.ai

EUV Source Power Requirementsare Set by Wafer Throughput Models


Original courtesy of Jos Benschopand Vadim Banine, ASML.

J. Benschop et al., SPIE 3997, 34 (2000),V. Banine and R. Moors, SPIE 4343, 203 (2002).

CollectableEUV power

60 W

Updated EUVpower and waferthroughput:

5 mj/cm2 resist300 mm wafers89 fields/wafer

Collectable, in-band,“clean” (no debris,no out-of-band)

EUV Power@ reticle

3.5 W

Power@ wafer140 mW

Illum. timeper field0.26 s

Illum. timeper wafer

23 s

Raw waferthroughput80 wafers/hr

120 W250 W

10

120 wafers/hr

Ch06_IonizaEnergXenon.ai


Ionization Energies for Xenon

...

. . .

Xenon (J. Gillaspy, NIST) +11 +10 +9 +8 +7 +6 43 44 45 46 47 48 e–s 259 232 206 180 107 93 eV

Xe + 10 4f → 4d linesare strong near 13.5 nm

Ch06_Xe_Sn_Spectra.ai


Comparative Spectra: Xe and Sn

80 0

1

2

3

4

5

0.5

1.5

1

2.5

2

3.5

3

9 10 11 12 13

4p54d9 → 4p64d8

5p → 4d

4p64d7(4f+5p) → 4p64d8

Xe+10

Xenon

• Debris is the issue

Tin

Sn+10

Rel

ativ

e in

tens

ity

14 15 16 17 18 12 13 14 15 16 1817 19 20nmnm

Courtesy of G. O’Sullivan (Univ. College Dublin) R. Faulkner (UCD Ph.D, 1999) A. Cummings (Nahond Univ. Ireland)

Laser Plasma Laboratory College of Optics & Photonics: CREOL & FPCE at UCF

The UCF tinThe UCF tin--doped droplet sourcedoped droplet source

Martin RichardsonK. Takenoshita, C-S Koay, S. George, T. Schmid, S. Teerawattansook R. Bernath, C. Brown

Laser Plasma LaboratoryCollege of Optics and Photonics & CREOL, UCF

Moza Al-RabbanQatar University

Howard ScottLawrence Livermore National Laboratory

Vivek BakshiSEMATECH

Funded by SEMATECH, SRC Intel and the State of Florida


The tinThe tin--doped droplet laser plasma EUV sourcedoped droplet laser plasma EUV source

Multi-component 30 -35 um diameter target at 30 kHz -- Location precision 3 um

Modest laser intensities I ~ 1011 W/cm2

Mass-limited targets

Target contains only 1013 tin atoms

Recently demonstrated 30 kHz laser droplet irradiation with intelligent feedback beam and target control – continuous operation for 8 hours


High CE demonstrated with Droplet TargetHigh CE demonstrated with Droplet Target

CE = 2% at 13.5 nm for tin-doped droplet target source

0.0

0.5

1.0

1.5

2.0

0 5 10 15 20 25 30

Co

nv

ers

ion

Eff

icie

ncy

Laser Intensity (x1010 Wcm-2)

0.0

0.5

1.0

1.5

2.0

0 5 10 15 20 25 30

Co

nv

ers

ion

Eff

icie

ncy

Laser Intensity (x1010 Wcm-2)

0.E+00

2.E+04

4.E+04

6.E+04

12.5 13.0 13.5 14.0 14.5

-0.1

0.1

0.3

0.5

0.7

Mirro

r Refle

ctivityPh

oto

n C

ou

nts

(A.U

)

spectrum Mirror R

at 13.5nm, CE = 2% at 13.6nm, CE = 2.25%

Wavelength (nm)

0.E+00

2.E+04

4.E+04

6.E+04

12.5 13.0 13.5 14.0 14.5

-0.1

0.1

0.3

0.5

0.7

Mirro

r Refle

ctivityPh

oto

n C

ou

nts

(A.U

)

spectrum Mirror R

at 13.5nm, CE = 2% at 13.6nm, CE = 2.25%

0.E+00

2.E+04

4.E+04

6.E+04

12.5 13.0 13.5 14.0 14.5

-0.1

0.1

0.3

0.5

0.7

Mirro

r Refle

ctivityPh

oto

n C

ou

nts

(A.U

)

spectrum Mirror R

0.E+00

2.E+04

4.E+04

6.E+04

12.5 13.0 13.5 14.0 14.5

-0.1

0.1

0.3

0.5

0.7

Mirro

r Refle

ctivityPh

oto

n C

ou

nts

(A.U

)

spectrum Mirror R

0.E+00

2.E+04

4.E+04

6.E+04

12.5 13.0 13.5 14.0 14.5

-0.1

0.1

0.3

0.5

0.7

Mirro

r Refle

ctivityPh

oto

n C

ou

nts

(A.U

)

spectrum Mirror R

at 13.5nm, CE = 2% at 13.6nm, CE = 2.25%

Wavelength (nm)

0.0

1.0

2.0

3.0

4.0

5.0

6.0

1.00E+10 1.00E+11 1.00E+12

Intensity (W/cm^2)

CE

(%

in 2

%B

W in

2P

I sr)

70 mJ60 mJ

CE = 5.5 % with solid tin!

CE = 3% achievable with droplet source--- for 30 kHz, 140 mJ laser

120 W / 2π

FOM FC2 teamF. Bijkerk S.A. vd Westen C. Bruineman

yrotarobaL amsalP resaL FCU ta ECPF & LOERC :scinotohP & scitpO fo egelloC

murtceps noissime ATU eht etalupinam won nac eW murtceps noissime ATU eht etalupinam won nac eWal

ized

Pho

ton

Cou

nt(A

.U.)

f::g:h

x 1.1 01 21:ix 6.8 01 11x 8.3 01 11x 4.1 01 11 /W mc 2

1x5.0 0 31

1x0.1 0 31

08 09 01 0 11 0 21 0 031 41 0 51 0 61 0Wa ev le ( htgn Å)

1x5.0 0 31

1x0.1 0 31

1x5.1 0 31

1x0.2 0 31

08 09 01 0 11 0 21 0 31 0 41 0 051 061 71 0 81 0 91 0 002Wa ev le ( htgn Å)

1x5.0 0 31

1x0.1 0 31

1x5.1 0 31

1x0.2 0 31

1x5.2 0 31

1x0.3 0 31

08 09 01 0 11 0 21 0 31 0 41 0 051 061 71 0 81 0 91 0 002

nS 9+

-bN Like t inAg ces( 1- )

aW velength ( Å)

nS 9+

0

21 .5 31 .0 13.5 14.0 14.5 51 .0 51 .5

Waveleng ht n( )m

Nor

mal

ized

Pho

ton

Co

a

b

c

d

.0 01x5 31

.1 01x0 31

.1 01x5 31

.2 01x0 31

.2 01x5 31

.3 01x0 31

08 09 001 011 021 031 041 51

nS 11+

-Y -Like t inAg (sec 1- )

Wa lev tgne h

.0 5x 01 31

.1 0x 01 31

.1 5x 01 31

.2 0x 01 31

.2 5x 01 31

.3 0x 01 31

08 09 01 0 011 21 0 31 0 041 51 0 61 0 071 81 0 91 0 002

Z L-r ki e t in( Ag s ce 1- )

Wave el ng ht Å( )

nS 1+ 0 nS 1+ 0

1x0.2 0 31

1x5.2 0 31

1x0.3 0 31

nS 9+

-bN Like t inAg ces( 1- )

nS 9+

0

02

04

06

08

001

021

041

061

1.0 0.1 01 01 00

02

04

06

08

001

021

041

061

1.0 0.1 01 01 0ytisnetnI resaL 01 x( 11 mc.W 2- )

Te, m

ax (e

V)0 01 001

eT pm re ruta e ( eV )

9.0

8.0

7.0

6.0

5.0

4.0

3.0

2.0

1.0

nS 1+

nS 2+

nS 3+

nS 4+

nS 5+

nS 6+

nS 7+

nS

nS 1+ 0

nS 8+nS 21+

nS 31+

nS 41+

nS 51+

Frac

tiona

l pop

ulat

ion

1 01 001eT pm re ruta e ( eV )

9.0

8.0

7.0

6.0

5.0

4.0

3.0

2.0

1.0

nS 1+

nS 2+

nS 3+

nS 4+

nS 5+

nS 6+

nS 7+

9+

nS

1+0

nS 1+ 1nS 8+

nS 21+nS 31+

nS 41+

nS 51+

Frac

tiona

l pop

ulat

ion

0

02

04

06

08

001

021

041

061

081

1.0 0.1 01 01 00

02

04

06

08

001

021

041

061

081

1.0 0.1 01 01 0ytisnetnI resaL 01 x( 11 mc.W 2- )

Te, m

ax (e

V)


0.1

9.0

8.0

7.0

6.0

5.0

4.0

3.0

2.0

1.0

nS 1+

nS 2+

nS 3+

nS 4+

nS 5+

nS 6+

nS 7+

nS

nS 1+ 0

nS 8+nS 21+

nS 31+

nS 41+

nS 51+

Frac

tiona

l pop

ulat

ion


0.1

9.0

8.0

7.0

6.0

5.0

4.0

3.0

2.0

1.0

nS 1+

nS 2+

nS 3+

nS 4+

nS 5+

nS 6+

nS 7+

9+

nS

1+0

nS 1+ 1nS 8+

nS 21+nS 31+

nS 41+

nS 51+

Frac

tiona

l pop

ulat

ion


Hydrodynamic Modeling: Effects of Laser WavelengthConversion efficiency Conversion efficiency -- Tin with other laser wavelengthsTin with other laser wavelengths

Condition: Tin-doped droplet, 35 µm dia, 10ns pulse, I = 1.0 x 1011 W/cm2

0.35µm: Te - Higher laser intensities required

1.0E+16

1.0E+18

1.0E+20

1.0E+22

1.0E+24

0 50 100 150 200

0

20

40

60Ne

Te

R(≅m)

0nsλ = 0.35 µm

Te

ne

Tcrit

1016

1018

1020

1022

1024

20

0

40

60

ne

(cm

-3) T

e (eV)

1.0E+16

1.0E+18

1.0E+20

1.0E+22

1.0E+24

0 100 200

0

20

40

60Ne

Te0nsλ = 1.0 µm

1016

1018

1020

1022

1024

20

0

40

60

ne

(cm

-3)

Te (eV

)

Tcrit

ne

Te

1.0E+16

1.0E+18

1.0E+20

1.0E+22

1.0E+24

0 100 200 300

0

20

40

60Ne

Te0nsλ = 10 µm

1016

1018

1020

1022

1024

ne

(cm

-3)

20

0

40

60T

e (eV)Tcrit

ne

Te

10µm: -Emission comes from lower ne region

March 2, 2005 5751-26 Emerging Lithographic Technologies IX, Microlithography 2005, San Jose, California

EUV Source System Development Update: Advancing Along the Path

to HVM

I.V. Fomenkov, D.W. Myers, B.A. Hansson, D.C. Brandt, A. Ershov, B. Klene

7March 2, 2005 5751-26 Emerging Lithographic Technologies IX, Microlithography 2005, San Jose, California

Development of a Laser Produce Plasma EUV Source has Significant Challenges

Laser

Cost/CoOExtraction Efficiency

Rep-ratePulse Width

Beam QualityPointing Stability

Beam Transport System

Coating LifetimePointing Stability

Drive laser multiplexing

Source Material/DeliveryCE

Droplet stabilityMaterial purityServiceability

Laser Window Protection

Lifetime

CollectorLifetime/Cost

ManufacturabilityDebris Mitigation

MLM Average ReflectivityMLM Stability

Other

Compliance RequirementsAlignmentMetrology

System complexity

11March 2, 2005 5751-26 Emerging Lithographic Technologies IX, Microlithography 2005, San Jose, California

Liquid Metal Droplet Generator Developed

Heated Reservoir

Droplet Generator

Vacuum Vessel

Lens

Plasma

Camera

h Continuous stimulated droplet generation of liquid metals (Li and Sn) at temperatures up to 250°C

h Droplets diameter ≤100 µmh Droplet rates up to 48 kHzh Working distance of 50mm

100 µm Sn droplets at 36 kHz, captured using strobe lighting

Ref: Poster #5751-108, Algots, Cymer

Philips’s EUV Source:

Update and Issues

J. Pankert, EUV Source Workshop San Jose 2005

Philips Extreme UV

Schematics of the source

+

laser

tin supply

excess tinremoval

cooling channel

Philips Extreme UV

Summary of the properties• Electrodes

– Rotating: scalability to very high powers– Regenerative electrodes:

• Liquid tin surface• Erosion problem fundamentally solved

• General properties– CE 2%– Pinch size < 1mm– 5 kHz demonstrated– 120 W continuous operation– 260 W short term (limited by vacuum vessel)

EUV Sources for Lithography (SPIE, November 2005)Vivek Bakshi, Editor

This comprehensive volume, edited by a senior technical staff member at SEMATECH, is the authoritative reference book on EUV source technology. The volume contains 38 chapters contributed by leading researchers and suppliers in the EUV source field. Topics range from a state-of-the-art overview and in-depth explanation of EUV source requirements, to fundamental atomic data and theoretical models of EUV sources based on discharge-produced plasmas (DPPs) and laser-produced plasmas (LPPs), to a description of prominent DPP and LPP designs and other technologies for producing EUV radiation. Addi-tional topics include EUV source metrology and components (collectors, electrodes), debris mitigation, and mechanisms of compo-nent erosion in EUV sources. The volume is intended to meet the needs of both practitioners of the technology and readers seeking an introduc-tion to the subject.

Prices: $127 / $150 (SPIE Member/List)(Available November 2005)

overview of euv lithography

Documents