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2015 International Symposium on Extreme Ultraviolet Lithography, Maastricht, NL
Edge placement error analysis for N7 logic patterning options
Oct-05-2015 ASML: Eelco van Setten, Eleni Psara, Friso Wittebrood, Dorothe Oorschot, Joep van Dijk, Guido Schiffelers, Jo Finders, Mircea Dusa IMEC: Vicky Philipsen, Eric Hendrickx
2015 International Symposium on Extreme Ultraviolet Lithography, Maastricht, NL
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2015 International Symposium on Extreme Ultraviolet Lithography, Maastricht, NL
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On the edge
or over the edgeโฆ
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2015 International Symposium on Extreme Ultraviolet Lithography, Maastricht, NL
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On the edge
or over the edgeโฆ
Photo: WFAA.Com Photo:nbcdfw.com
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2015 International Symposium on Extreme Ultraviolet Lithography, Maastricht, NL
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Edge Placement Error combines all CD and OVL errors
Design intent
After patterning
EP tolerance Y
EP tolerance X
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2015 International Symposium on Extreme Ultraviolet Lithography, Maastricht, NL
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Edge Placement Error combines all CD and OVL errors
EPEinter= (๐๐)๐๐๐,๐ข๐ง๐ญ๐๐ซ๐ +
๐๐๐๐๐๐ฅ๐ข๐ง๐๐ฌ
๐
๐
+๐๐๐๐๐๐๐ฎ๐ญ๐ฌ
๐
๐
EPEintra= (๐๐)๐๐๐,๐ข๐ง๐ญ๐ซ๐๐ +
๐๐๐๐๐๐ฅ๐ข๐ง๐๐ฌ
๐
๐
+๐๐๐๐๐๐๐ฎ๐ญ๐ฌ
๐
๐
EPElocal= (๐๐)๐๐๐๐ +
(๐๐)๐๐๐๐๐ฅ๐ข๐ง๐๐ฌ
+(๐๐)๐๐๐๐๐๐๐ฎ๐ญ๐ฌ
๐
EPEmax = EPEinter + EPEintra + EPElocal
die
die
die
die
die
โฆโฆ.
Uncorrelated edges
EPEglobal
EP tolerance Y
EP tolerance X
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2015 International Symposium on Extreme Ultraviolet Lithography, Maastricht, NL
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Main overlay and CD error sources
Overlay errors
CD errors
Machine overlay
Image placement
Mask registration
Pattern transfer
Litho cluster CDU
OPC residuals
Mask CDU
Pattern transfer
Global (die/wfr scale) Local (pitch scale)
E-beam/resist stochastics
Resist/etch stochastics
E-beam/resist stochastics
Resist/etch stochastics
LCDU/resist stochastics
LPE/resist stochastics
die
die
die
die
die
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Contents
Edge Placement Error
Patterning options for N7
Overlay errors
CD errors
Summary & conclusions
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2015 International Symposium on Extreme Ultraviolet Lithography, Maastricht, NL
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Design options for critical N7 Logic Metal layers
Uni-directional (1D) M1 Bi-directional (2D) M1
โข Design freedom
โข Design restrictions
โข Additional layers required
โข Litho friendly
BUTโฆ
โข Challenging for litho
BUTโฆ
Complementary litho: 1D direct print / 2D direct print
ArFi SAQP EUV cut/block
+ =
EUV EUV
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2015 International Symposium on Extreme Ultraviolet Lithography, Maastricht, NL
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Evaluation done on NXE:33x0B EUV scanner NXE:33x0B
NA 0.33
Illumination Conventional 0.9s,
6 off-axis pupil settings
Tip-to-tip (T2T)
Cut/block 1D direct print / 2D direct print
Staggered CHs (Irregular) cuts
Y. Borodovsky, Intel, 2012 Intโl
Workshop on EUVL, Maui, Hi
Goal: Compare relative performance using EPE model
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Contents
Edge Placement Error
Patterning options for N7
Overlay errors
CD errors
Summary & conclusions
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2015 International Symposium on Extreme Ultraviolet Lithography, Maastricht, NL
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MMO:
โข X = 2.0 nm
โข Y = 2.2 nm
DCO:
โข X = 1.0 nm
โข Y = 0.6 nm
NXE:3350: 2.0nm Matched Machine OVL and 1.0nm
Dedicated Chuck OVL demonstrated
On-product overlay NXE:3300B to NXT:1960Bi:
measured = 5-nm, correction towards 4โnm possible
NXE:3350B: OPO < 3.5nm expected, to be demonstrated
NXE:3350B
Source P ~ 60-
80W
MMO
Jan Mulkens et al, SPIE 2015
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2015 International Symposium on Extreme Ultraviolet Lithography, Maastricht, NL
-0.5
0
0.5
1
1.5
-100 -50 0 50 100
Cut-X Annular
Cut-Y Annular
Cut-X Conv
Cut-Y Conv
Pla
cem
en
t Er
ror
[nm
]
Focus[nm]
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Image placement errors through focus can be minimized
by mask and pupil optimization
For more details see โExperimental verification of phase induced M3D effects in EUV imagingโ โ Friso Wittebrood
M3D simulation 21/22nm HP cuts
Annular Conventional
Cut-X
Cut-Y
-0.5
0
0.5
1
1.5
-100 -50 0 50 100
Trench Dip90Y
Trench FlexPupil
Gap Dip90Y
Gap FlexPupil
Pla
cem
en
t Er
ror
[nm
] Focus[nm]
Dip90Y FlexPupil
M3D simulation T2T @ 16nm HP
Gap Trench
Pattern placement aware SMO, โEUV Reticle Enhancement Techniques for k1 0.4 and belowโ SPIE 2015 โ Stephen Hsu et al
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2015 International Symposium on Extreme Ultraviolet Lithography, Maastricht, NL
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Local Placement Error on mask gives systematic
overlay error at pitch scale
Pitch scale
Mask local placement error:
Deviation from designed position at pitch scale
Method:
โข Measure center of gravity for 9x9 cuts within array (CD SEM) โข Average over ~64 fields ~ 8x noise reduction
โข Calculate distance in X/Y between cuts
โข Calculate delta w.r.t. design distance (pitch)
โข Calculate 3ฯ over rel. X/Y placement error
ฮ=0.5 ฮ=-1.1
ฮ=-0.5 ฮ=0.8
ฮ=0.7 ฮ=-0.1 ฮ=0.1
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2015 International Symposium on Extreme Ultraviolet Lithography, Maastricht, NL
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Systematic Local Placement Error (mask) ~
1.0nm for both CHs/ cuts and T2T
0.0
0.5
1.0
1.5
2.0
22p44 staggeredCHs
21/22nm HP cuts
X
Y
LPE
[nm
3ฯ
; 1
x]
Mask LPE for CHs and cuts
0
0.5
1
1.5
2
12 20
22p44 T2T
LPE
[nm
3ฯ
; 1
x]
Design gap [nm; 1x]
Mask LPE of T2T gap
Derived from wafer measurements
Pitch scale
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Contents
Edge Placement Error
Patterning options for N7
Overlay errors
CD errors
Summary & conclusions
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2015 International Symposium on Extreme Ultraviolet Lithography, Maastricht, NL
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NXE:3350: 0.6nm FWCDU demonstrated for horizontal
16nm HP L/S and 20nm iso trenches
16nm dense L/S 20nm iso trenches
CDU CD FW CDU IF CDU
H line 16.1nm 0.6nm 0.5nm
CDU CD FW CDU IF CDU
H trench 21.0nm 0.6nm 0.4nm
Reticle and shadowing error corrected
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2015 International Symposium on Extreme Ultraviolet Lithography, Maastricht, NL
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Good CD control for both cut and T2T features Cut-X CDU is 1.0nm 3ฯ
CD (X/Y) FW CDU
(X/Y)
IF CDU
(X/Y)
21.9nm
71.3nm
1.0nm
2.0nm
0.8nm
1.6nm
CDU 21/22nm HP cuts
NXE:3350B
X-cut Y-cut
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2015 International Symposium on Extreme Ultraviolet Lithography, Maastricht, NL
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Good CD control for both cut and T2T features Cut-X CDU is 1.0nm 3ฯ
CD FW CDU IF CDU
30.9nm 2.9nm 2.2nm
CDU T2T @ 16nm HP
NXE:3300B NXE:3350B
0
0.5
1
1.5
2
2.5
3
0
20
40
60
80
100
120
22p44CHS
Feat -1 Feat -2 Feat -3 Feat -4
Mean X Mean YFW CDU X FW CDU YIF CDU X IF CDU Y
CD
[n
m]
CD
U [
nm
3ฯ
]
CDU 21/22nm HP cuts
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2015 International Symposium on Extreme Ultraviolet Lithography, Maastricht, NL
0
2
4
6
8
10
22p44CHS
Feat -1 Feat -2 Feat -3 Feat -4
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Cuts show better LCDU performance than line ends
0
2
4
6
8
10
12 14 16 18 20 25 30
Meas
Sim
LGU
[n
m 3ฯ
]
Design gap [nm; 1x]
LCDU 21/22nm HP cuts LGU for T2T โ 16nm HP
LCD
U [
nm
3ฯ
]
Pitch scale
Estimated SEM contribution ~ 3nm 3ฯ
LCDU Diameter
Estimated SEM contribution ~ 1nm 3ฯ
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2015 International Symposium on Extreme Ultraviolet Lithography, Maastricht, NL
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Local CDU can be minimized by maximizing contrast
LCDU CH data LGU T2T data
0
5
10
15
20
8 18 28 38
p32 - DY90
p40 - Q45
p44 - Q45
LGU
[n
m 3ฯ
] 1/ILS [nm]
NXE:3300 CAR data
High contrast Low contrast
๐ฟ๐บ๐ ๐๐ ~ 0.35
๐ผ๐ฟ๐+ 1.5
0.0
1.0
2.0
3.0
4.0
5.0
0.10 0.20 0.30 0.40 0.50 0.60
20
22
24
30
35
High contrast Low contrast
๐ฟ๐ถ๐ท๐ ๐๐ ~6.6
๐๐ผ๐ฟ๐+ 1.1
NXE:3300 CAR data HP (nm)
1/NILS [-]
LCD
U [
nm
3ฯ
]
Data courtesy: Sander Wuister, ASML
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2015 International Symposium on Extreme Ultraviolet Lithography, Maastricht, NL
0
5
10
15
20
5 15 25 35
p32 - DY90
p40 - Q45
p44 - Q45
CH - All data
LCD
U /
LG
U [
nm
3ฯ
]
1/ILS [nm]
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Local CDU can be minimized by maximizing contrast
LCDU CH and LGU T2T data
NXE:3300 CAR data
High contrast Low contrast
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2015 International Symposium on Extreme Ultraviolet Lithography, Maastricht, NL
2.0
2.2
2.4
2.6
2.8
3.0
3.2
3.4
12 13 14 15 16 17 18 19 20 21 22
0.33NA 38% PFR
0.33NA 20% PFR
NXE:33x0
NXE:3400
L/S HP [nm]
NIL
S [-
]
Horizontal L/S
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Contrast optimization by OPC, pupil and absorber
optimization
BF shift & Bossung tilt
Pa
rtly
fa
din
g
Laurens de Winter et al. EMLC 2015
Contrast optimization:
โข Pupil optimization: โข Pupil fill ratio NXE:33x0 = 38%
โข Pupil fill ratio NXE:3400 = 20%
โข OPC / SMO, eg. SRAFs
โข Mask stack optimization Resolution enhancement
Stephen Hsu et al. SPIE 2015
No AF
With AF
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Contents
Edge Placement Error
Patterning options for N7
Overlay errors
CD errors
Summary & conclusions
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2015 International Symposium on Extreme Ultraviolet Lithography, Maastricht, NL
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Main EPE contributors are Local CDU and on product OVL
โข Process / etch optimization expected to reduce Local CDU up to
30-50% for CHs/cuts and 10-30% for line ends
Main contributors to EPE budget (after litho)
Cut (X/Y) T2T
OPO (TBC) [nm 3ฯ] ~3.5 ~3.5
LPE [nm 6ฯ] ~2.0 / 2.4 ~2.4
CDU/2 [nm 3ฯ] ~0.5 / 1.0 ~1.45
LCDU/2 [nm 6ฯ] ~4 ~8
EPEglobal= (๐๐)๐๐๐๐ +
๐๐๐๐๐๐ฅ๐ข๐ง๐๐ฌ
๐
๐
+๐๐๐๐๐๐๐ฎ๐ญ๐ฌ
๐
๐
EPElocal= (๐๐)๐๐๐๐ +
(๐๐)๐๐๐๐๐ฅ๐ข๐ง๐๐ฌ
+(๐๐)๐๐๐๐๐๐๐ฎ๐ญ๐ฌ
๐
die
die
die
die
die
Cut (X/Y) T2T
OPO (TBC) [nm 3ฯ] ~3.5 ~3.5
LPE [nm 6ฯ] ~2.0 / 2.4 ~2.4
CDU/2 [nm 3ฯ] ~0.5 / 1.0 ~1.45
LCDU/2 [nm 6ฯ] ~4 ~8
LCDU/2 [nm 6ฯ] AEI ~2-3 ~5.5-7
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Conclusions
EPE model:
โข Includes overlay and CD errors at global and local scale
โข Allows balancing of overlay and (L)CDU requirements
EPE model used to compare relative performance difference for cutmask and tip-to-tip:
โข Local CDU and on-product OVL dominate the EPE budget
โข Local gap uniformity more difficult to control than local CDU of contacts and cuts driven by contrast (ILS)
OPC/ SMO, pupil and mask stack optimization are powerful knobs to improve:
โข Contrast LCDU reduction
โข Placement errors through focus OPO reduction
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2015 International Symposium on Extreme Ultraviolet Lithography, Maastricht, NL
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The authors would like to thank:
โข NXE Applications team
โข Thijs Hollink
โข Vidya Vaenkatesan
โข Cheuk-Wah Man
โข John McNamara
โข Frank Horsten
โข Rik Hoefnagels
โข Marieke Meeuwissen
โข Kees Ricken
โข Others
โข Sander Wuister
โข Leon Levasier
โข Marcel Beckers
โข Martien de Rooij
โข Martin Verhoeven
โข Pieter Woltgens
โข Jan Mulkens
โข Gian Lorusso
โข Lieve Van Look
โข Dan Corliss
โข NXE simulation team
โข Gijsbert Rispens
โข Paul Colsters
โข Laurens de Winter
โข Kateryna Lyakhova
โข Cemil Kaya
โข Gerardo Bottiglieri
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2015 International Symposium on Extreme Ultraviolet Lithography, Maastricht, NL
Thank you for your
attention !