EUV Workshop / June. 12, 2008 1
Progress in EUV resist developmentT. Shimokawa, T. Kai, D. Shimizu, K. Maruyama, A. Saitou, Y. Hishiro†,
Semiconductor Materials Laboratory, JSR Corporation.†JSR Micro, INC.
2008 International Workshop on EUV LithographyJune. 12, 2008
EUV Workshop / June. 12, 2008 2
Contents
Current status and issues of EUV resist
Material development
• Molecular glass (Noria)
• High acid generation resin
Summary
EUV Workshop / June. 12, 2008 3
Resist Character Exposure result
APHS resin TPS PAG
EUV exposure result (Polymer-type)
30nmL/S 26nmL/S28nmL/S
Resolution limit: 26nmL/S, LWR@ 50nmL/S = 5.9nm
Resist A (PHS resin and TPS PAG) resolved 26 nm L/S patterns.
24mJ 24mJ 24mJLWR 7.7nm LWR 6.7nm LWR 7.1nm
(Evaluation Condition) MET at LBNL, on-Bare-Si, FT:70 nm, SB 130C-60s, PEB 130C-60s, development time 60s.
EUV Workshop / June. 12, 2008 4
Evaluation results of EUV resistPerformance Resist A
Resist requirement(ITRS 2007)Character
BasePHS Polymer
TPS PAGType CAR
Resolution (1:1 L/S) 26 nm (resolution limit) 32 nm (with Process Margin)Sensitivity 24 mJ/cm2 5-30 mJ/cm2
LWR-3σ(Low frequency) 6.7 nm @28nm LS 1.7 nmOutgas 1.0×1014 -1015 molecules/cm2 6.5×1014 molecules/cm2*
EL 7.5% @30nm LS -DOF 0.06um @30nm LS -
*:SEMATECH’s spec for microexposure tool
For 32nmhp and beyond, sensitivity, LWR and resolution are needed further improvement. Additionally, outgass must be decreased.
The acceleration of novel material development is needed.
EUV Workshop / June. 12, 2008 5
Contents
Current status and issues of EUV resist
Material development
• Molecular glass (Noria)
• High acid generation resin
Summary
EUV Workshop / June. 12, 2008 6
Material development
LWRLWR
ResolutionResolution
SensitivitySensitivity
OutgasOutgas
1.Molecular glass
2. Polymer bound PAG with anion pendant type
3.Bulky protecting group
4.Photo-destructive base
5.High acid generation resin
6.High quantum yield PAG with bulky structure
Issue Novel materialMain effect Concept•Smaller molecule Size
•Smaller grain size
• Homogeneity• Acid diffusion control
Volatile control from resin
Acid diffusion control
Higher acid amount
• Higher acid amount• Volatile control from PAG
Status of molecular glass and high acid generation resin are reported.
EUV Workshop / June. 12, 2008 7
Concept of molecular resist
Large grain size Small grain size
Dev. Dev.
Large LWR Small LWR
exposure
Image figure
LWR improvement
Large grain size Small grain size
Dev. Dev.
Poor resolution High resolution
Small Grain (low molecular?)Large grain(ca.20nm PHS)
exposureResolution improvement
Large Grain(ca.20nm PHS)Small Grain (low molecular?)
EUV Workshop / June. 12, 2008 8
It is possible to introduce various protecting group etc.
Higher thermal stability than other molecular glass
Noria1)
Noria was selected as molecular glass for our molecule resist.
Small molecular size(ca.2nm)
More rigid structure than other molecular glass
CharacterNoria
OHHO
HO
OH HO
OH
OH
HO
HO OH
OH
OH
HOHO
OHOH
HO OH
OH HOHO OH
OH OH
OHHO HClOHC-(CH2)3-CHO+
Resorcinol Glutaraldehyde(1,5-Pentanedial)
80 oC, 48 hin Ethanol
83% Yield
1) Nishikubo et al., Angew. Chem. Int. Ed. 2006, 45, 7948-7952
EUV Workshop / June. 12, 2008 9
Noria - Physical property 1-
Physical property
PHS resinPHS resin NoriaNoria
Molecular weight (Mw) Approx.10000 Approx.2000Polydispersity >1.1 1.0Thermal stability 180℃(Tg) >300℃(weight loss)
Molecular size*(calculation) Approx.7 nm Approx.2 nm
Grain size** Approx.17 nm Approx.13 nm
Surface roughness*** Approx.14nm Approx.10nm
OHHO
HO
OH HO
OH
OH
HO
HO OH
OH
OH
HOHO
OHOH
HO OH
OH HOHO OH
OH OHOH
80
In collaboration with Prof. Nishikubo Kanawagwa Univ.
Noria showed smaller molecular size, grain size and surface roughness than that of PHS resin.
Noria has high thermal stability.
*Calculation method: MD, **Grain size was obtained from AFM image about protected PHS resin only and protected Noria only after coating, ***Surface roughness was obtained from AFM image about resist comprising of protected Noria and protected resin after half exposure.
EUV Workshop / June. 12, 2008 10
Noria - Physical property 2-
Physical property
Other molecular glassOther molecular glass Protected Protected NoriaNoria
Distribution of protecting ratio
In collaboration with Prof. Nishikubo Kanawagwa Univ.
Protected Noria showed narrower distribution of protecting ratio than that of other molecular glass.
OR1R1O
R1O
OR1 R1O
OR1
OR1
R1O
R1O OR1
OR1
OR1
R1OR1O
O1ROR1
R1O OR1
OR1 R1OR1O OR1
OR1OR1
R1 : H or protecting groupR2 : H or protecting group
0 20 40 60 80 100
20
40
60
80
100
00 20 40 60 80 100
20
40
60
80
100
0
Protecting ratio(%)* Protecting ratio(%)**Ex
iste
nce
ratio
(%)
Exis
tenc
e ra
tio(%
)
Wide Narrow
EUV Workshop / June. 12, 2008 11
28nmL/S 26nmL/S
24nmL/S
Exposure Result (Resolution)
(Evaluation Condition) MET at LBNL, on-BARC, FT:70 nm, SB 140C-90s, PEB 130C-90s, development time 60s.
Resist B showed good resolution.
EUVL
33mJ 33mJ
33mJ
Protected-Noria
TPS salt
S3
X
R1 : H or protecting group
OR1R1O
R1O
OR1 R1O
OR1
OR1
R1O
R1O OR1
OR1
OR1
R1OR1O
O1ROR1
R1O OR1
OR1 R1OR1O OR1
OR1OR1
Resist B
EUV Workshop / June. 12, 2008 12
Exposure Result (ELBOW)
(Evaluation Condition) MET at LBNL, on-BARC, FT:70 nm, SB 140C-90s, PEB 130C-90s, development time 60s.
50 nm Elbow pattern
EUVL
Protected-Noria
TPS salt
S3
X
R1 : H or protecting group
OR1R1O
R1O
OR1 R1O
OR1
OR1
R1O
R1O OR1
OR1
OR1
R1OR1O
O1ROR1
R1O OR1
OR1 R1OR1O OR1
OR1OR1
Resist B
EUV Workshop / June. 12, 2008 13
(Evaluation Condition) MET at LBNL,on-BARC, FT:70 nm, SB 140C-90s, PEB 130C-90s, development time 60s.
Exposure Result (LWR)
LWR of resist B at 28nm L/S pattern was 6.1 nm.
EUVL
28nmL/S
50nmL/S 40nmL/S
32nmL/S
LWR=5.6nm LWR=6.4nm
LWR=6.3nm LWR=6.1nm
33mJ 33mJ
33mJ 33mJ
Protected-Noria
TPS salt
S3
X
R1 : H or protecting group
OR1R1O
R1O
OR1 R1O
OR1
OR1
R1O
R1O OR1
OR1
OR1
R1OR1O
O1ROR1
R1O OR1
OR1 R1OR1O OR1
OR1OR1
Resist B
EUV Workshop / June. 12, 2008 14
Litho performance of molecular resist applied Noria
Performance Resist A Resist B
Resist requirement(ITRS 2007)Character
BasePHS Polymer
TPS PAG
Noria(molecular glass)
TPS PAGType CAR CAR
Resolution(1:1 L/S)
26 nm(resolution limit)
28 nm(resolution limit)
<26 nm(pattern collapse)
32 nm (with Process Margin)
Sensitivity 24 mJ/cm2 33.0 mJ/cm2 5-30 mJ/cm2
LWR-3σ(Low frequency)
6.7 nm @28nm LS
6.1 nm @28nm LS 1.7 nm
Noria showed comparable litho performance to PHS resin.
EUV Workshop / June. 12, 2008 15
Molecular glass - Future Action -
Molecular glassMolecular glass
1. Formulation optimization of Noria2. Molecular glass with PAG
Current system Current system New system New system
PAGPAG
Each components exists separately
Molecular glassMolecular glass
PAGPAG
PAG is integrated into Molecular glass
Optimization of formulation is ongoing.Molecular glass with PAG is under development.
EUV Workshop / June. 12, 2008 16
Contents
Current status and issues of EUV resist
Material development
• Molecular glass (Noria)
• High acid generation resin
Summary
EUV Workshop / June. 12, 2008 17
e- + AG A + G-
High acid generation resin -Acid generation mechanism-
2.
3.
AG: Acid Generator、A: Decomposed fragment of AG, G-: Counter Anion of AG
HS unit is good unit for proton supply
Amount of secondary electron is increased by high absorption unit
To improve sensitivity
Increasing reaction rate of secondary electron with AG
1.
OHOH
+ e
OH OH
+ G HG+
EUV
XX is high absorption unit
X・+ x
*
OHHigh acid generation resin
Development status of high acid generation resin is reported.
EUV Workshop / June. 12, 2008 18
Absorption of EUV1) Proc. SPIE. 3997, P.588, 2000.2) Atomic Data and Nuclear Data
tables. 54(2), P.181, 1993.
Atomic NumberPhot
oabs
orpt
ion
cros
s se
ctio
ns μ
(cm
2 /mol
)
CH
F
To increase absorption, N, O and F are available candidates
SHig
h Ab
sorp
tion
N
Si
Element Advantage Disadvantage
N 1.None 1.Act as quencher
O 1.Less reactivity with electron 1.Etching resistance
F1.High absorption
1.High reactivity with electron2. Outgassing (HF?)3.Etching resistance
Development status of F rich resin is reported.
O and F was selected as available candidates
EUV Workshop / June. 12, 2008 19
Resin into which F is incorporated
OH
HS
Funit
PHS Resin=100(Ref)
HS/monomer with F=75/25
FT:100nm
Measured at Osaka university
Sample
Resin
PAGTPS-Tf
Composition Amount of generated PHS(Ref)=100 Ref
HS/monomer with F=75/25 20%UPHS/monomer with F=50/50 25%UP
Under 100nm FT, amount of generated acid increased with increasing ratio of fluorinated monomer. Litho performance is being evaluated.
Additionally, O rich resin is being prepared.
HS/monomer with F=50/50
EUV Workshop / June. 12, 2008 20
Contents
Current status and issues of EUV resist
Material development
• Molecular glass (Noria)
• High acid generation resin
Summary
EUV Workshop / June. 12, 2008 21
SummaryCurrent status and issues of EUV resist
•For 32nmhp and beyond, sensitivity, LWR and resolution are needed further improvement. •Additionally, outgass must be decreased.•The acceleration of novel material development is needed.
Material development to improve resolution and LWRMolecular glass Noria
•Noria showed smaller molecular size, grain size and surface roughness than that of PHS resin.
•Noria showed high thermal stability.•Protected Noria showed narrower distribution of protecting ratio than that of other molecular glass.•Noria showed comparable litho performance to PHS resin.
Material development to improve sensitivity High acid generation resin
• Under 100nm FT, amount of generated acid increased with increasing ratio of fluorinated monomer.
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