© imec 2005

From From ArFArF Immersion to Immersion to EUV LithographyEUV Lithography

Luc Van den hoveVice President IMEC

© imec 2005

Outline

Introduction

193nm immersion lithography

EUV lithography

Global collaboration

Conclusions

© imec 2005 Source: 2003 ITRS - Exec. Summary

ITRS Technology Trends – MPU Gate Length

1

10

100

1000

1995 2000 2005 2010 2015 2020Year

Gat

e Le

ngth

(nm

)

2-year Node Cycle

3-year Node Cycle

Lithography is enabling…

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Rayleigh equation

NAkresolution λ.1=

Lord Rayleigh

Wave length scaling

193nm

157nm

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157nm Challenges

Catadioptric lens design

Fluorinated resist materials Mask technology

Modified SiO2

Pellicle: none / soft / hard Purging N2 fill

• transmission• radiation hardness• reticle heating

Surface contaminationModified SiO2

Pellicle: none / soft / hard Purging N2 fill

• transmission• radiation hardness• reticle heating

Surface contamination

Surface contamination

CaF2 lens material

© imec 2005

Outline

Introduction

193nm immersion lithography

EUV lithography

Global collaboration

Conclusions

193nm immersion lithographyStatus, Challenges, Outlook

© imec 2005

Rayleigh equation

NAkresolution λ.1=

Lord Rayleigh

NA scaling

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rrff00 sinsinsin θηθηθη ===NA

Immersion LithographyImprovements in resolution

Snell’s law :

nglass

ηr

ηglass

η0

ηf

ηr

liquid

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rrff00 sinsinsin θηθηθη ===NA

Immersion LithographyImprovements in resolution

Snell’s law :

nglass

ηr

ηglass

η0

ηf

ηr

liquiddry

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Immersion Litho

Extremely shortintroduction time

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Immersion demonstration in record time

20022003

2004

March 2002: Key note presentation @ SPIE Santa ClaraBurn Lin (TSMC): First suggestion to consider immersion lithography

Wafer

Last Lens Element

Mirror Mirror

VacuumFilterPump

Tank CoverFluid

InletFluid Outlet

FluidReplenishingHole

Drain

Fluid

ThermalControl

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Immersion demonstration in record time

20022003

2004

March 2002: Key note presentation @ SPIE Santa ClaraBurn Lin (TSMC): First suggestion to consider immersion lithography

October / November 2003:ASML and IMEC demonstrate feasibility on 0.75NA immersion prototype scanner

First immersion scanning image on Oct 7, 2003

0

200

400

600

800

1000

1200

180 270 160 270 200 320 160 270 160 270

0.92-0.72 +Att PSM

0.89-0.65 +Att PSM

0.89-0.65 +BIN

0.89-0.65 +BIN

0.89-0.45 +BIN

DRYW ET

DO

F @

8%

EL

> 50% DOF gain demonstration

© imec 2005

Immersion demonstration in record time

20022003

2004

March 2002: Key note presentation @ SPIE Santa ClaraBurn Lin (TSMC): First suggestion to consider immersion lithography

October / November 2003:ASML and IMEC demonstrate feasibility on 0.75NA immersion prototype scanner

January 2004: Sematech Lithography Forum Los AngelesWorld momentum shifts entirely from 157nm to immersion lithography

© imec 2005

Immersion demonstration in record time

20022003

2004

March 2002: Key note presentation @ SPIE Santa ClaraBurn Lin (TSMC): First suggestion to consider immersion lithography

October / November 2003:ASML and IMEC demonstrate feasibility on 0.75NA immersion prototype scanner

January 2004: Sematech Lithography Forum Los AngelesWorld momentum shifts entirely from 157nm to immersion lithography

193nm immersion

157nm

© imec 2005

Immersion demonstration in record time

20022003

2004

March 2002: Key note presentation @ SPIE Santa ClaraBurn Lin (TSMC): First suggestion to consider immersion lithography

October / November 2003:ASML and IMEC demonstrate feasibility on 0.75NA immersion prototype scanner

January 2004: Sematech Lithography Forum Los AngelesWorld momentum shifts entirely from 157nm to immersion lithography

End 2004:multiple 2nd generation 0.85 NA immersion scanners have been shipped (TSMC, IMEC)

© imec 2005

Immersion LithographyA few challenges

Lens dimensions

Process interactions

Defectivity

Polarization effects-1 +1-1 +1

© imec 2005

Immersion LithographyA few challenges

Lens dimensions

Process interactions

Defectivity

Polarization effects-1 +1-1 +1

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Process Interactions

Interaction of resist/top coat with water

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Process interactionsSome topcoats reveal an intrafield CD fingerprint similar to the soak simulations

Soak simulation CD fingerprint

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Process interactions

CD soak fingerprint using new developer soluble topcoats is significant reduced compared to TSP3A (but still visible)

TSP3A TILC019 TCX007

New developer soluble topcoats

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Immersion LithographyA few challenges

Lens dimensions

Process interactions

Defectivity

Polarization effects-1 +1-1 +1

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Immersion defectivity

A spherical air bubble casts a shadow

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“Bubble Defects”

Simulated (2-beam imaging) aerial image of 500nm bubble defect on 100nm L/S pattern

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Bubble improvement (/1250i)

Non-optimized conditions After optimization

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Immersion specific defects

Resist leaching(resist conposition, use of top coat, …)

Hydrophobicity(material contact angle,material response to water droplets, …)

Water quality(particles, bacteria, TOC, …)

Resist/process contributions

α = 70° α = 105°

Bubbles(related to shower head design,wafer chuck design, …)

Defects(related to water residues, related to chuck/head design, …)

Scanner contributions

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Immersion LithographyA few challenges

Lens dimensions

Process interactions

Defectivity

Polarization effects-1 +1-1 +1

© imec 2005

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

-11-1

08-1

01-94-874

-80-736

-66-59-52 -46

-39-322

-25-184

-11 -46

2 9.2

16 2329 3643 50

657 64

471 78

285 9298105112

Inte

nsi

ty

Polarization at high NA

Angle of incidencein resist

20°

Medium NA (0.6) in resist (n=1.7)

Medium NA (0.6) in resist (n=1.7)

-1 +1

Image contrast 70% Image contrast 92%

NA=0.6

-1 +1

X-polarized (TM) Y-polarized (TE)

© imec 2005

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1-8

1-7

6-7

2-6

8-6

4-6

0-5

6-5

2-4

8-4

4-4

0-3

6-3

2-2

8-2

4-2

0-1

6-1

2-8

.1 -4 04.

038.

0512

.116

.120

.124

.228

.232

.236

.240

.344

.348

.352

.356

.460

.464

.468

.472

.576

.580

.5

Polarization at high NA

Angle of incidencein resist

30°

-1 +1

Image contrast 49% Image contrast 92%

-1 +1

NA=0.85X-polarized (TM) Y-polarized (TE)

High NA (0.85) in resist (n=1.7)

High NA (0.85) in resist (n=1.7)

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X-polarized (TM)

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8-5

2-4

9-4

7-4

4-4

2-3

9-3

6-3

4-3

1-2

9-2

6-2

3-2

1-1

8-1

6-1

3-1

0-7

.8-5

.2-2

.6 02.

65.

27.

810

.4 1315

.618

.220

.823

.4 2628

.631

.233

.836

.4 3941

.644

.246

.849

.4 52

Polarization at high NA

Angle of incidencein resist

50°

Very High NA (1.3 immersion) in resist (n=1.7)

Very High NA (1.3 immersion) in resist (n=1.7)

-1 +1

Image contrast -8% Image contrast 59%

-1 +1

Y-polarized (TE)NA=1.3

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Contrast enhancement with polarization

BE+6.6% BE+3.3% BE BE-3.3% BE-6.6%

Un-polarized

BE+15.4% BE+10.3% BE+5.1% BE BE-5.1% BE-10.2% BE-15.4%

Polarized

SRAM, half pitch 55 nm, pitch 110 nm, 6% att PSM, dipole Y

Designadjustments

0.93 NAdry

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Immersion LithographyA few challenges

Lens dimensions

Process interactions

Defectivity

Polarization effects-1 +1-1 +1

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Hyper NA: lens cost

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Hyper NA: lens cost

G-line lens1975

193nm lens2003

>1000 mm

>300 mm

© imec 2005

0

2

4

6

8

10

12

0.63 0.75 0.85 0.93 0.93 i 1.1 i 1.2 i 1.3 i

Lens

com

plex

ityExpected according geometrical scaling dioptric

1.43 i1n air n water

Air Water

NA

Cost innovations in Optics for hyper NA

Released or expected dioptricNew catadioptric design

© imec 2005

Outline

Introduction

193nm immersion lithography

EUV lithography

Global collaboration

Conclusions

193nm immersion lithographyStatus, Challenges, Outlook