EUV Lithography Optics for sub 9 nm...
Transcript of EUV Lithography Optics for sub 9 nm...
EUV Lithography Optics for sub 9 nm Resolution
October 29th, 2014 · Washington, D.C., USA
Sascha Migura, Bernhard Kneer, Jens Timo Neumann, Winfried Kaiser (ZEISS), Jan van Schoot (ASML)International Symposium on Extreme Ultraviolet Lithography
2Carl Zeiss SMT GmbH, Sascha Migura EUV Lithography Optics for sub 9 nm Resolution October 29th, 2014
MET(Micro Exposure Tools)
ADT(-Demo Tool)
Starlith 3100™
Starlith 3300™
2003 2006 2009 2012
HVM series productionHVM series productionsmall seriessmall seriesprototypesprototypes
EUV program at ZEISS.
High-NA
3Carl Zeiss SMT GmbH, Sascha Migura EUV Lithography Optics for sub 9 nm Resolution October 29th, 2014
This talk is about resolution.
NAResolution = k1
λ∙
NA 0.33 … 0.4 … 0.5 … 0.6
Resolution @ k1=0.3single exposure / nm 12.3 … 10.1 … 8.1 … 6.8
What happens when increasing the NA of an EUV tool? What are the optical solutions?
EUV 13.5nmHigh‐NA
4Carl Zeiss SMT GmbH, Sascha Migura EUV Lithography Optics for sub 9 nm Resolution October 29th, 2014
Agenda.
1
2
3
The Solution: Anamorphic Lithography.
The Dilemma of High‐NA EUVL.
The Optical Systems.
5Carl Zeiss SMT GmbH, Sascha Migura EUV Lithography Optics for sub 9 nm Resolution October 29th, 2014
intermediate focus
collector
Reticle (mask)
wafer
plasma
illuminator
field facet mirror
pupil facet mirror
projectionoptics
source
diffractionorders
0th 1st-1st
Mask = grating
Finer resolution leads to larger
diffraction angles.
0th 1st-1st
Overall optical column.
6Carl Zeiss SMT GmbH, Sascha Migura EUV Lithography Optics for sub 9 nm Resolution October 29th, 2014
intermediate focus
collector
Reticle (mask)
wafer
plasma
illuminator
field facet mirror
pupil facet mirror
projectionoptics
source
Overall optical column.
Projectionoptics catchesand combines
thesediffraction
orders on tothe wafer
7Carl Zeiss SMT GmbH, Sascha Migura EUV Lithography Optics for sub 9 nm Resolution October 29th, 2014
Fields and light cones at reticle and wafer are connected via MAG.
@ wafer@ reticle
Projection withMAG 4x
104 mm
132
mm x
y
26 mm
33 m
m
y
z
NA
NA @ reticle = NA
MAG
CRAO 6°NA 0.33
slit
8Carl Zeiss SMT GmbH, Sascha Migura EUV Lithography Optics for sub 9 nm Resolution October 29th, 2014
Increasing NA, light cones @ reticle start to overlap.
@ reticle
104 mm
132
mm
26 mm
33 m
m
y
z
@ wafer
Projection withMAG 4x
CRAO 6°NA 0.45
x
y
9Carl Zeiss SMT GmbH, Sascha Migura EUV Lithography Optics for sub 9 nm Resolution October 29th, 2014
To separate light cones again, CRAO must be increased.
@ reticle
104 mm
132
mm
26 mm
33 m
m
y
z
@ wafer
Projection withMAG 4x
CRAO 9°NA 0.45
x
y
10Carl Zeiss SMT GmbH, Sascha Migura EUV Lithography Optics for sub 9 nm Resolution October 29th, 2014
reticleStrong shadowing
Weak shadowing
Absorber thickness 55nm.
Absorber shadowing @reticle is angular dependent.
11Carl Zeiss SMT GmbH, Sascha Migura EUV Lithography Optics for sub 9 nm Resolution October 29th, 2014
reticleNA 0.33CRAO 6°15nm L&S
Standard ML
NA 0.45CRAO 9°11nm L&S
Standard ML
ML on
lyML &absorber
0th order imbalance: telecentricity
error
0th/1st order imbalance:contrast loss
Absorber shadowing for a CRAO of 9° leads to imbalanced pupils, and hence to telecentricity errors and loss of image contrast.
12Carl Zeiss SMT GmbH, Sascha Migura EUV Lithography Optics for sub 9 nm Resolution October 29th, 2014
0
10
20
30
40
50
60
70
80
90
100
NA 0.33, CRAO 6° 15nm
Horizontal L&S
NA 0.45, CRAO 9° 11nm
Horizontal L&S
NA 0.33, CRAO 6° 15nm
Vertical L&S
NA 0.45, CRAO 9° 11nm
Vertical L&S
Con
trast
[%]
inacceptablecontrast loss
less pronounced –diffraction orders not in
folding direction
NXE:3300
High-NA
Due to shadowing, a system with MAG 4x and 9° CRAO does not resolve even 11 nm hp using a standard multilayer @ reticle.
NA 0.33, CRAO 6°
15nmHorizontal L&S
NA 0.45, CRAO 9°
11nmHorizontal L&S
NA 0.45, CRAO 9°
11nmVertical L&S
NA 0.33, CRAO 6°
15nmVertical L&S
imaging simulations
13Carl Zeiss SMT GmbH, Sascha Migura EUV Lithography Optics for sub 9 nm Resolution October 29th, 2014
The only way to decrease angular spread @reticle is to increase MAG.
@ reticle
y
z
@ wafer
Projection withMAG 4x
CRAO 6°
14Carl Zeiss SMT GmbH, Sascha Migura EUV Lithography Optics for sub 9 nm Resolution October 29th, 2014
Changing MAG is changing field sizes: Same mask leads to 13 mm slit…
@ wafer@ reticle
Projection withMAG 8x
104 mm
132
mm
y
z
CRAO 6°
x
y
13 mm
16.5
mm
15Carl Zeiss SMT GmbH, Sascha Migura EUV Lithography Optics for sub 9 nm Resolution October 29th, 2014
@ wafer@ reticle
Projection withMAG 8x
208 mm
264
mm
x
y
y
z
26 mm
33 m
m
…or keeping 26 mm slit requires a large mask.
CRAO 6°
16Carl Zeiss SMT GmbH, Sascha Migura EUV Lithography Optics for sub 9 nm Resolution October 29th, 2014
The Dilemma of High-NA EUVL.
MAG 4x, CRAO 9°, FF
@ wafer@ reticle
1.)
MAG 8x, CRAO 6°, QF2.)
MAG 8x, CRAO 6°, FF3.)
imaging
small field
large mask
17Carl Zeiss SMT GmbH, Sascha Migura EUV Lithography Optics for sub 9 nm Resolution October 29th, 2014
1 The Dilemma of High‐NA EUVL:High‐NA EUVL requires a new optical solution.
2
3
The Solution: Anamorphic Lithography.
The Optical Systems.
Agenda.
18Carl Zeiss SMT GmbH, Sascha Migura EUV Lithography Optics for sub 9 nm Resolution October 29th, 2014
Reduce angles by increasing MAG only in the direction that matters...
@ wafer@ reticle
104 mm
132
mm
y
z
CRAO 6°
x
y
19Carl Zeiss SMT GmbH, Sascha Migura EUV Lithography Optics for sub 9 nm Resolution October 29th, 2014
…which enables a High-NA EUVL optical system with 26mm slit.
@ wafer@ reticle
Projection with
104 mm
132
mm
y
z
26 mm
16.5
mm
QFCRAO 6°NA >0.5
MAG 4x in xMAG 8x in y
x
y
20Carl Zeiss SMT GmbH, Sascha Migura EUV Lithography Optics for sub 9 nm Resolution October 29th, 2014
For anamorphic Half Field, the illumination optics must provide entrance pupils with anamorphic settings.
isomorphicMAG 4x, FF
anamorphicMAG 4x/8x, HF
Example: c-quad illumination setting
x
y
@ reticle
21Carl Zeiss SMT GmbH, Sascha Migura EUV Lithography Optics for sub 9 nm Resolution October 29th, 2014
An anamorphic lens transforms entrance pupils with anamorphic settings into circular settings @ wafer.
@ wafer@ reticleExample: c-quad illumination setting
x
y
MAG 4x in xMAG 8x in y
22Carl Zeiss SMT GmbH, Sascha Migura EUV Lithography Optics for sub 9 nm Resolution October 29th, 2014
The anamorphic High-NA design enables sub 9 nm resolution imaging using a standard multilayer @ reticle.
NXE:3300
isomorphic
anamorphic
0
10
20
30
40
50
60
70
80
90
100
NA 0.33, CRAO 6°isomorphic 4x
15nmHorizontal L&S
NA 0.45, CRAO 9°isomorphic 4x
11nmHorizontal L&S
NA >0.5, CRAO 6°anamorphic 4x/8x
8.1nmHorizontal L&S
NA >0.5, CRAO 6°anamorphic 4x/8x
8.1nmVertical L&S
Contrast [%
]
contrastrestored
NA 0.33, CRAO 6°isomorphic 4x
15nmHorizontal L&S
NA 0.45, CRAO 9°isomorphic 4x
11nmHorizontal L&S
NA >0.5, CRAO 6°anamorphic 4x/8x
8.1nmHorizontal L&S
NA >0.5, CRAO 6°anamorphic 4x/8x
8.1nmVertical L&S
imaging simulations
23Carl Zeiss SMT GmbH, Sascha Migura EUV Lithography Optics for sub 9 nm Resolution October 29th, 2014
The Solution: Anamorphic Lithography.Anamorphic Half Field is enabling High‐NA EUVL.
1
2
3
The Dilemma of High‐NA EUVL:High‐NA EUVL requires a new optical solution.
The Optical Systems.
Agenda.
24Carl Zeiss SMT GmbH, Sascha Migura EUV Lithography Optics for sub 9 nm Resolution October 29th, 2014
Reticle levelWe have designs for such anamorphic High-NA optics available.
Really big optical system with very large mirrors and extreme aspheres at increased accuracy requirements
Challenge to optics technology and manufacturing
NA 0.25 NA 0.33 NA >0.5
Reticle level
Design examples
Wafer level
Reticle level
25Carl Zeiss SMT GmbH, Sascha Migura EUV Lithography Optics for sub 9 nm Resolution October 29th, 2014
NXE:3300unobscured pupil
High-NAobscured pupil
waferM5
M6
M5
M6
wafer
By narrowing the angles in the optical system, we see potential to improve the optical column transmission by a factor ~2 wrt NXE:3300.
Example: Central obscuration reduces angles on M5.
Generic Lines & Spaces through pitchsimulation
26Carl Zeiss SMT GmbH, Sascha Migura EUV Lithography Optics for sub 9 nm Resolution October 29th, 2014
The Optical Systems:Technical solutions for optical systems look feasible.
1
2
3
The Solution: Anamorphic Lithography.Anamorphic Half Field is enabling High‐NA EUVL.
The Dilemma of High‐NA EUVL:High‐NA EUVL requires a new optical solution.
Agenda.
27Carl Zeiss SMT GmbH, Sascha Migura EUV Lithography Optics for sub 9 nm Resolution October 29th, 2014
Conclusions.
Anamorphic Lithography with Half Field is making High-NA EUVLeconomically feasible with NA >0.5 and utilizing existing 6‘‘ maskinfrastructure.
The considered optical concept has potential to increase thetransmission of the optical column by a factor of ~2 wrt NXE:3300.
28Carl Zeiss SMT GmbH, Sascha Migura EUV Lithography Optics for sub 9 nm Resolution October 29th, 2014
Acknowledgements.
EUVL Teams at ASML & ZEISS and at our partners
Federal Ministry of Education and Research (Germany)for funding of the projects 13N9112 and 13N10567 within theframework of the MEDEA+ / CATRENE programs and the BMBF project 13N12256
29Carl Zeiss SMT GmbH, Sascha Migura EUV Lithography Optics for sub 9 nm Resolution October 29th, 2014