© 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)
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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
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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)
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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
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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