Surface Morphology Diagram for Cylinder-Forming Block Copolymer Thin Films Xiaohua Zhang
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Transcript of Surface Morphology Diagram for Cylinder-Forming Block Copolymer Thin Films Xiaohua Zhang
Surface Morphology Diagram Surface Morphology Diagram for Cylinder-Forming Block for Cylinder-Forming Block
Copolymer Thin FilmsCopolymer Thin Films
Xiaohua Zhang
Center for Soft Condensed Matter Physics and Interdisciplinary ResearchCenter for Soft Condensed Matter Physics and Interdisciplinary Research
Soochow UniversitySoochow University
Phase diagram for a block copolymer with various structures
Current Solutions
• Needs - 3D nanostructure Manufacturing - 3D characterization of nanostructure - Control of 3D nanostructure• Current Problems - 2D structures - Physical Template
200 nm 200 nm
Y. Gong et al Macromolecules 2006 39, 3369
T. Russell et al Adv. Mater. 2004 16, 226
Background
A B
Orientation of Cylinders
T. Russell et al Langmuir, 2008, 24, 3545
Challenges•Contain defects in many self assembled nanostructures. • Lack sufficient long-range order for certain nanotechnology applications.
O2 RIE
CF4 RIE
J. Cheng, Nature Materials, 3, 823-828(2004)
O2 RIE
CF4 RIE
35 nm period
Hitachi Global Storage Technologies
Self-assembling Materials for Bottom-up Nanofabrication ProcessesSelf-assembling Materials for Bottom-up Nanofabrication Processes
Assembly of Block Copolymer FilmsAssembly of Block Copolymer FilmsOur goal:• Develop critical measurement solutions that enable nanomanufacturing with guided block copolymer assembly for next generation magnetic data storage, nanoscale electronics, and high efficiency membranes for energy. Method:•Combine unique modeling platforms with precision thermal processing techniques to enable the development of small angle x-ray and neutron scattering to measure structural uniformity, including orientation distributions, and pattern placement in self-assembled polymer films within templated surfaces.
•Controlling Orientation using Cold Zone Annealing (CZA), sample preparation procedure and unique
thermal processing technique
•Metrology of Orientation in Nanostructured Films
•Metrology of Orientation in Nanostructured Films
•3D Nanostructure for Cylinder-Forming Block Copolymer Thin Films
SELECTIVE REMOVAL OF ONE OF THE
BLOCKS
RIE ETCH
SELECTIVE REMOVAL OF ONE OF THE
BLOCKS
RIE ETCH
128 136 144 152 160 168 176 184
60
80
100
120
140
160
180
2
3
4
5
6
7
hf / L
0
Parallel
Mixed
Perpendicular
hf /
nm
T / oCSpin Coating
Flow Coating without Residual Solvent
3D Nanostructure3D Nanostructure
Flow Coating
200nm
C. M Stafford et al. Rev. Sci. Instr. 11(2006) 023908-1
Materials:Poly (styrene-block-methyl methacrylate) Mn: PS(35500)-PMMA(12200) Mw/Mn: 1.04
Surface Morphology Diagram of PS-PMMA Block Copolymer Films on Surface Morphology Diagram of PS-PMMA Block Copolymer Films on Oxide Silicon SubstrateOxide Silicon Substrate
200nm
Film thickness: 120 nmAnnealing: 155˚C for 15 h Prebaking: 93 ˚C for 15 h
Spin-coated in air Flow-coated in air
Spin-coated in toluene vapor Spin-coated in toluene vapor & prebaked prior to annealing
Sample Preparation Procedure DependenceSample Preparation Procedure Dependence
128 136 144 152 160 16860
80
100
120
140
160
180
200
2.4
3.2
4.0
4.8
5.6
6.4
7.2
8.0
hf / L
0
hf /
nm
T / oC
Surface Morphology DiagramSurface Morphology Diagram
AFM phase images of flow coated PS-b-PMMA block copolymers after annealing at 147 ˚C for 15 h.
s
PMMA
PS
Increasing Film Thickness
58nm 71nm
104nm 130nm 168nm
86nm
200nm
ik
okq
θ θ
Incidentneutrons
Detector
Sample
2 q
ik
ok
ok
ik
θ θ
2
qx
qz
io
i
kkq
k
2
2θ
3D Characterization of Nanostructure by Neutron Reflectivity (NR)3D Characterization of Nanostructure by Neutron Reflectivity (NR)
NCNR in NIST
dPS-b-PMMA, 80 nm, 147 dPS-b-PMMA, 80 nm, 147 ooC for 15 hC for 15 h
200nm
0 200 400 600 8000.000000
0.000001
0.000002
0.000003
0.000004
0.000005
0.000006
0.000007
Z(Å)
SL
D
Air Si
We convert from beam-coordinates (qx,qy,qz) to sample-coordinates (Qx,Qy,Qz) using a rotation matrix
Orientation Distribution Measurement of 3D Nanostructure by RSANS Orientation Distribution Measurement of 3D Nanostructure by RSANS
cossin
sincos
zxz
yy
zxx
qqQ
qqQ
Qy
Qx
Qz
Samples show a mix of parallel and perpendicular cylinder scattering
Hexagonal pattern from laying-down cylinders
Scattering peak from standing-up cylinders
Low-q scattering from size disorder
Weak ring from random component
Annealing:147ºC for 15h
Content of perpendicular cylinders:80%
Film thickness:136nm
200nm
Annealing:165ºC for 15h
Content of perpendicular cylinders:59%
Film thickness:141nm
Data was fit by extending the model of Ruland and Smarsly.Ruland, W.; Smarsly, B. J. Appl. Cryst. 2005, 38, 78-86.
0.00 0.03 0.06 0.09 0.12 0.1510-6
10-5
10-4
10-3
10-2
10-1
100
q(Å-1)
Re
fle
cti
vit
y
Flow-Coated Film
300 600 9000.0
0.1
0.2
0.3
Vo
lum
e F
racti
on
Air Si
Z(Å)
16% Residual Solvent
10-6
10-5
10-4
10-3
10-2
10-1
100
0.00 0.03 0.06 0.09 0.12
Spin-coated Film
Re
fle
cti
vit
yq(Å-1)
0 300 600 9000.0
0.1
0.2
0.3
Z(Å)
Vo
lum
e F
ract
ion
Air Si12% Residual Solvent
PS-b-PMMA in deuterated toluene
NR Measurements on Residual Solvent in PS-b-PMMA Films NR Measurements on Residual Solvent in PS-b-PMMA Films
Self-assembly Driving Force of 3D NanostructureSelf-assembly Driving Force of 3D Nanostructure
0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.141E-6
1E-4
0.01
1
100
51 kg/mol
818 kg/mol
97 kg/mol
24 kg/mol
Re
fle
cti
vit
y
q(Å-1)
0.006 0.008 0.010 0.012
0.1
1
10
100
1000
Re
fle
cti
vit
y
q(Å-1)
0 200 400 600 800-2
-1
0
1
2
(v
ol%
)
Mn(kgmol-1)
0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.161E-6
1E-4
0.01
1
100
147 nm
208 nm
91 nm
41 nm
Re
fle
cti
vit
y
q(Å-1)
0.006 0.008 0.010 0.012 0.014 0.016
0.01
1
100
Re
fle
cti
vit
y
q(Å-1)
0 400 800 1200 1600 20001.30
1.35
1.40
1.45
1.50
1.55
1.60
147 nm
Z(Å)
SL
D1
0-6,(
Å-2)
41 nm
91 nm
0 50 100 150 200 250-2
-1
0
1
2
(v
ol%
)
d (nm)
208 nm
PS Film Thickness and Molecular Weight Dependence PS Film Thickness and Molecular Weight Dependence
1E-6
1E-4
0.01
1
100
0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14
0.004 0.006 0.008 0.010 0.012 0.0141E-3
0.01
0.1
1
10
100
1000
Re
fle
cti
vit
y
q(Å-1)
As Cast
One-step Two-step
Re
fle
cti
vit
y
q(Å-1)
NR data (symbols) of as-cast, one-step (93 oC for 15 h) and two-step (93 oC for 15 h followed by 155 oC for another 15 h) annealed PMMA films with as-cast film thickness of 121 nm at fixed molecular weight (20 kg/mol).
60 90 120 150 180 2100.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
(v
ol%
)
d (nm)
0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14 0.161E-6
1E-4
0.01
1
100
169 nm
201 nm
121 nm
69 nm
Re
fle
cti
vit
y
q(Å-1)
0.006 0.008 0.010 0.012 0.014 0.016
0.01
1
100
Re
fle
cti
vit
y
q(Å-1)
NR scans (symbols) measured from the PMMA films of different thickness at fixed molecular weight (20 kg/mol).
PMMA FilmsPMMA Films
0 200 400 600 800 1000 1200
1.04
1.06
1.08
1.10
1.12
1.14
1.16
1.18 As Cast
Z(Å)
SL
D1
0-6,(
Å-2)
One-step
0.0
0.3
0.6
0.9
1.2
1.5
1.8
(v
ol%
)
Thermal HistoryOne-stepAs Cast Two-step
Two-step
FTIR Characterization of Residual Solvent in BCP FilmsFTIR Characterization of Residual Solvent in BCP Films
Samples Residual solvent concentration (weight)
PMMA as cast film from 3% d-Toluene solution 1.2 ± 0.2 %
PMMA baked and dried in vacuum oven (repeat) < 0.2%
PS as cast from 3% d-Toluene solution (repeat) < 0.4%
PS baked and dried in vacuum oven < 0.4%
The estimation of residual d-toluene concentration is based on its characteristic peak located around 2274 cm -1. Calibration is made with the area ratio of the strong bands corresponding to d-toluene (2274 cm -1) and PMMA (1730 cm-1) in the FTIR spectra of 3% polymer solution.
220022202240226022802300232023402360
0.0000
0.0002
0.0004
0.0006
0.0008
0.0010
0.0012
0.0014
0.0016
0.0018
Toluene-d8 Peak
Annealed PS
As-cast PS
Annealed PMMA
As-cast PMMA
Wavenumbers(cm-1)
Ab
sorb
ance
PS (51kg/mol) PMMA (20kg/mol) Film thickness : 160 nm.
Macromolecules 2010, 43, 1117–1123.ACS Nano, 2008, 2, 2331-2341.
• Film preparation procedure, and other processing effects, cannot be ignored in nanomanufacturing applications.
• Fundamentally demonstrate the interplay between interplay between intrinsic BCP structure and processing conditionsintrinsic BCP structure and processing conditions.
• R-SANS and NR can deduce orientational distribution orientational distribution in BCP cylinder thin films.
SummarySummary