ExCITe T406 – WP 1 - EUV Resist TechnologyQuarterly Meeting
Athens, 11/12. 5. 2005
Excite T406
Acid Diffusion in CARs
–Exposure latitude
– Impact on Line Edge Roughness
David Van Steenwinckel, Jeroen Lammers, Hans Kwinten (Philips Research Leuven)
Peter Leunissen (IMEC)
ExCITe T406 – WP 1 - EUV Resist TechnologyQuarterly Meeting
Athens, 11/12. 5. 2005
Introduction
100nm pitch
Rela
tive #
dep
rote
cted
S
ites
(a.u
.)
0
1
2
3
4
5
6
-100 -50 0 50 100
Ld = 0nm
Ld = 30nm
Ld = 60nm
200nm pitch
Position (nm) Position (nm)
Impact of acid diffusion on chemical contrast
ExCITe T406 – WP 1 - EUV Resist TechnologyQuarterly Meeting
Athens, 11/12. 5. 2005
• Diffusion has major impact on max. EL
12
14
16
18
20
22
30 40 50 60 70 80 90 100
Ld (nm)
EL
(%
)
• Scaling with pitch• Ld = 68nm on 320nm pitch
translates to 0.21 Ld /pitch
Experiment:320nm pitch
NA=0.75Dipole =
0.89/0.6NILS = 2.3
Relation EL - Ld
ExCITe T406 – WP 1 - EUV Resist TechnologyQuarterly Meeting
Athens, 11/12. 5. 2005
12
14
16
18
20
22
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
Ld/pitch
EL
(%
)
• EL scaling with NILS
Relation EL - Ld
• Scaling with pitch• Ld = 68nm on 320nm pitch
translates to 0.21 Ld /pitch
Experiment:320nm pitch
NA=0.75Dipole =
0.89/0.6NILS = 2.3
• Diffusion has major impact on max. EL
ExCITe T406 – WP 1 - EUV Resist TechnologyQuarterly Meeting
Athens, 11/12. 5. 2005
0
3
6
9
12
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
Ld/pitch
EL
(%)
/ N
ILS
160nm HP
0
3
6
9
12
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
160nm HP
120nm HP
80nm HP
Theory
Relation EL - Ld
ExCITe T406 – WP 1 - EUV Resist TechnologyQuarterly Meeting
Athens, 11/12. 5. 2005
0
3
6
9
12
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
Ld/pitch
EL
(%)
/ N
ILS
120nm HP
160nm HP
0
3
6
9
12
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
160nm HP
120nm HP
80nm HP
Theory
Relation EL - Ld
ExCITe T406 – WP 1 - EUV Resist TechnologyQuarterly Meeting
Athens, 11/12. 5. 2005
0
3
6
9
12
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
Ld/pitch
EL
(%)
/ N
ILS
80nm HP
120nm HP
160nm HP
0
3
6
9
12
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
160nm HP
120nm HP
80nm HP
Theory
Relation EL - Ld
ExCITe T406 – WP 1 - EUV Resist TechnologyQuarterly Meeting
Athens, 11/12. 5. 2005
0
3
6
9
12
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
Ld/pitch
EL
(%)
/ N
ILS ArF - 160nm HP
ArF - 120nm HP
ArF - 80nm HP
EUV - 50nm HP
Theory
Relation EL - Ld
EL / NILS 0.12
ExCITe T406 – WP 1 - EUV Resist TechnologyQuarterly Meeting
Athens, 11/12. 5. 2005
5
6
7
8
9
10
20 30 40 50 60 70 80 90 100
Ld (nm)
LE
R 3
(
nm
)
Factors affecting LER
Contrast
Shot Noise100nm 1:1 lines
ExCITe T406 – WP 1 - EUV Resist TechnologyQuarterly Meeting
Athens, 11/12. 5. 2005
5
6
7
8
9
10
20 30 40 50 60 70 80 90 100
Ld (nm)
LE
R 3
(
nm
)
Shot noise scaling:Poisson statistics
NNLER N 1~
100nm 1:1 lines
Shot Noise
N = number of acid molecules influencing deprotection statistics
Factors affecting LER
ExCITe T406 – WP 1 - EUV Resist TechnologyQuarterly Meeting
Athens, 11/12. 5. 2005
5
6
7
8
9
10
20 30 40 50 60 70 80 90 100
Ld (nm)
LE
R 3
(
nm
)N = number of acid molecules influencing deprotection statistics
100nm 1:1 lines
Shot noise scaling:Poisson statistics
NNLER N 1~ N
Photon densityExposure Dose
Volume affected by acid molecules
Shot Noise
Factors affecting LER
ExCITe T406 – WP 1 - EUV Resist TechnologyQuarterly Meeting
Athens, 11/12. 5. 2005
NNLER N 1~ 5
6
7
8
9
10
11
20 30 40 50 60 70 80 90 100
Ld (nm)
LE
Rco
rr_
do
se 3
(
nm
)
5
6
7
8
9
10
11
20 30 40 50 60 70 80 90 100
Ld (nm)
LE
Rco
rr_
do
se 3
(
nm
)
100nm 1:1 lines
N
Photon densityExposure Dose
Volume affected by acid molecules
Relation LER – Ld
Scaling LER - Ld
p
LMTFLLER ddiff
ddosecorr
2/3
_1
(Ld)3
Shot noise scaling:Poisson statistics
Shot Noise
ExCITe T406 – WP 1 - EUV Resist TechnologyQuarterly Meeting
Athens, 11/12. 5. 2005
5
6
7
8
9
10
11
20 30 40 50 60 70 80 90 100
Ld (nm)
LE
Rco
rr_
do
se 3
(
nm
)
100nm 1:1 lines
Optical
Chemical
Relation LER – Ld
Contrast
Shot Noise
ExCITe T406 – WP 1 - EUV Resist TechnologyQuarterly Meeting
Athens, 11/12. 5. 2005
5
6
7
8
9
10
11
20 30 40 50 60 70 80 90 100
Ld (nm)
LE
Rco
rr_
do
se 3
(
nm
)
Scaling LER - Ld
p
LMTFLLER ddiff
ddosecorr
2/3
_1
p
LMTFLLER ddiff
ddosecorr
2/3
_1
5
6
7
8
9
10
11
20 30 40 50 60 70 80 90 100
Ld (nm)
LE
Rco
rr_
do
se 3
(
nm
)
100nm 1:1 lines
Best LER
Relation LER – Ld
Contrast
Shot Noise
ExCITe T406 – WP 1 - EUV Resist TechnologyQuarterly Meeting
Athens, 11/12. 5. 2005
Conclusions
Acid Diffusion Length LEREL
ExCITe T406 – WP 1 - EUV Resist TechnologyQuarterly Meeting
Athens, 11/12. 5. 2005
Conclusions
Acid diffusion is an important resist process parameter to tune crucial lithographic process characteristics
– EL was altered by factor of 4
– LER changed by 40%
Scaling of EL and LER with diffusion length was successfully described by two validated formulas
For a given dose, EL and LER cannot be optimized simultaneously
– e.g. Optimum diffusion length for LER reduction is one third of the pitch,
EL then drops to 40% of best achievable
ExCITe T406 – WP 1 - EUV Resist TechnologyQuarterly Meeting
Athens, 11/12. 5. 2005
Acknowledgments
P. Dirksen (Philips Research Leuven)
M. Ercken and N. Vandenbroeck (IMEC)
This work is sponsored through the Excite MEDEA+ T406 project, and the More Moore IST-1-507754-IP project.
ExCITe T406 – WP 1 - EUV Resist TechnologyQuarterly Meeting
Athens, 11/12. 5. 2005
0
3
6
9
12
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7
Ld/pitch
EL
(%)
/ N
ILS
80nm HP
120nm HP
160nm HP
Theory
EL / NILS = MTFdiffMTFdiff
Relation LER – Ld
ExCITe T406 – WP 1 - EUV Resist TechnologyQuarterly Meeting
Athens, 11/12. 5. 2005
Introduction
Resolution
Dose
Line Edge RoughnessAcid Diffusion Length
Shot Noise StatisticsNumber of PixelsR. Brainard et al. Proc. SPIE, 5374, 74 (2004)
ExCITe T406 – WP 1 - EUV Resist TechnologyQuarterly Meeting
Athens, 11/12. 5. 2005
Introduction
ResolutionChemical Contrast Exposure Latitude
Dose
Line Edge RoughnessAcid Diffusion Length
Shot Noise StatisticsNumber of PixelsR. Brainard et al. Proc. SPIE, 5374, 74 (2004)
ExCITe T406 – WP 1 - EUV Resist TechnologyQuarterly Meeting
Athens, 11/12. 5. 2005
Introduction
Resolution Chemical ContrastExposure Latitude
Dose
Line Edge RoughnessAcid Diffusion Length
Shot Noise StatisticsNumber of PixelsR. Brainard et al. Proc. SPIE, 5374, 74 (2004)
ExCITe T406 – WP 1 - EUV Resist TechnologyQuarterly Meeting
Athens, 11/12. 5. 2005
Introduction
Acid Diffusion Length LEREL
ExCITe T406 – WP 1 - EUV Resist TechnologyQuarterly Meeting
Athens, 11/12. 5. 2005
Experimental Setup
• ArF resist: GAR8105G1 (FFEM)• Experimental matrix
• Acid diffusion lengths characterized using ENZ Theory• P. Dirksen et al., Proc SPIE, 5377, p150 (2004)• D. Van Steenwinckel et al., Proc. SPIE, 5753, paper 32 (2005)
115°C110°C 120°C
110°C
115°C
120°C
SBPEB
x x x
x x x
x x x
ExCITe T406 – WP 1 - EUV Resist TechnologyQuarterly Meeting
Athens, 11/12. 5. 2005
0
20
40
60
80
PEB 110C PEB 115C(std.)
PEB 120C
SB110C
SB115C
SB120C
Acid Diffusion Length (Ld)
Ld as characterized with ENZ
methodology
Observations:
– Large increase in Ld with PEB
temperature
– Small decrease in Ld with SB
temperatureAci
d D
iffusi
on L
eng
th (
nm
)
ExCITe T406 – WP 1 - EUV Resist TechnologyQuarterly Meeting
Athens, 11/12. 5. 2005
Outline
Acid Diffusion Length LEREL
ExCITe T406 – WP 1 - EUV Resist TechnologyQuarterly Meeting
Athens, 11/12. 5. 2005
Outline
Acid Diffusion Length LEREL
