Upload
vothuan
View
216
Download
3
Embed Size (px)
Citation preview
1
Y. Leterrier - SwissLaser Net Workshop, Basel, June 25, 2008
Encapsulation of Organic Photonic Elements
Y. LeterrierLaboratoire de Technologie des Composites et Polymères (LTC)
Ecole Polytechnique Fédérale de Lausanne (EFPL)CH-1015 Lausanne, Switzerland
SwissLaser Net Workshop, Basel, June 25, 2008
Y. Leterrier - SwissLaser Net Workshop, Basel, June 25, 2008
Polymers are (too) permeablePolymers are (too) permeable
Crank & Park, ‘Diffusion in polymers’ Academic Press (1968)Chatam, Surf. Coat. Technol. (1996)Pauly, in ‘Polymer Handbook’ Wiley (1999)
10-4
10-3
10-2
10-1
100
101
102
103
104
10-7 10-5 10-3 10-1 101 103
OT
R (
100 u
m;
cm
3/m
2/d
ay/b
ar)
WVTR (100 um; g/m2/day)
PP
LDPE
HDPE
LCP
Cellulose
PA6PET
PEN
PVDC
PC
PS
ABS
EVOH(dry)
EVOH(wet)
PAN
PVC
OLEDdisplays
Solarmodules
Foodproducts
2
Y. Leterrier - SwissLaser Net Workshop, Basel, June 25, 2008
Polymersubstrate
Inorganic film(10-1000 nm)
BIF ~ 100
BIF ~ 1’000
BIF > 105
BIF ?
Barrier Improvement Factor: BIF = Ps/P
nanolaminates
Organic-inorganic hybrids
High-Barrier StrategiesHigh-Barrier Strategies
Y. Leterrier - SwissLaser Net Workshop, Basel, June 25, 2008
h
P=hc
Pc
+hs
Ps
Coatingpermeability Pc, thickness hc
Substratepermeability Ps, thickness hs
Nanosized Nanosized inorganic coatings/polymer compositesinorganic coatings/polymer composites
OTR
(cm
3 /day
/m2/
bar)
Coating thickness (nm)0.1
1
10
100
1000
0 100 200 300 400 500
PECVD
Evaporation
Sputtering
PET
AlOx
Aluminized PET
SiOx/PET films
Leterrier, Prog. Mater. Sci (2003)
3
Y. Leterrier - SwissLaser Net Workshop, Basel, June 25, 2008
Defects in vapor-deposited inorganic films on polymersDefects in vapor-deposited inorganic films on polymers
Roberts et al., J. Membrane Sci. (2002)Rochat, Leterrier, Månson, Fayet, Surf. Coat Technol. (2003, 2006)
Defectdependentpermeation
Critical coatingthickness ranges
between 8 and 15 nm
Courtesy Tetra Pak
3.10 3.15 3.20 3.25 3.30 3.35 3.40 3.45 3.50-24
-23
-22
-21
-20
-19
-18
-17
-16
-15
Temp (1/
OK) x 10
3
ln P
Ep (PET)
= 32.4±1.3 KJ/mole
Ep (SiOx_PET)
= 34.4 ± 2.1 KJ/mole
SiOx/PET
Y. Leterrier - SwissLaser Net Workshop, Basel, June 25, 2008
10 nm SiOx on PET @ 10% strain
Effect of coating defects on failure of barrierEffect of coating defects on failure of barrier
Rochat, Leterrier et al., J. Appl. Phys. (2003)Singh, Leterrier, Månson, Fayet, Surf. Coat. Technol. (2007)
1 µm
0
100
200
300
400
500
600
0
20
40
60
80
100
120
0 0.02 0.04 0.06 0.08 0.1
Cra
ck d
en
sit
y [
mm
-1]
Oxyg
en
tra
nsm
issio
n r
ate
[cm
3/m
2/d
ay/b
ar]
Strain
10 nm
50 nm
4
Y. Leterrier - SwissLaser Net Workshop, Basel, June 25, 2008
Polymersubstrate
Inorganic film(10-1000 nm)
BIF ~ 100
BIF ~ 1’000
BIF > 105
BIF ?
Barrier Improvement Factor: BIF = Ps/P
nanolaminates
Organic-inorganic hybrids
High-Barrier StrategiesHigh-Barrier Strategies
Y. Leterrier - SwissLaser Net Workshop, Basel, June 25, 2008
Why Why nanolaminate nanolaminate structures?structures?
BIF > 105
Nanolaminates decouple defect structure
WVTR (20°C) ~ 2·10-6 g/m2/day(Vitex Systems, CA)
Trophsa & Harvey, J. Phys. Chem. B (1997)
5
Y. Leterrier - SwissLaser Net Workshop, Basel, June 25, 2008
Trophsa & Harvey, J. Phys. Chem. B (1997)Schaepkens et al., J. Vac. Sci. Technol (2004)
Modeling of gas transportModeling of gas transport
Barrier improvement obtained when adding a second inorganic layer
Y. Leterrier - SwissLaser Net Workshop, Basel, June 25, 2008
-8.6 × 10-6‘5’[SiNx/SiOx]nGE (graded UHB)
~ 1 × 10-5
3.6 × 10-6
~ 1 × 10-6
W V T R(g.m-2.day)
1.04(SiN/lacquer)2Applied Materials
1.0‘12’ + topcoat[SiNx/SiOx]nPhilips (NONON)
0.810[acrylate/Al2O3]nVitex (Barix)
Crack OnsetStrain (%)
Number of layersEncapsulationStructure
Producer
Nanolaminate Nanolaminate encapsulationencapsulation
6
Y. Leterrier - SwissLaser Net Workshop, Basel, June 25, 2008
Polymersubstrate
Inorganic film(10-1000 nm)
BIF ~ 100
BIF ~ 1’000
BIF > 105
BIF ?
Barrier Improvement Factor: BIF = Ps/P
nanolaminates
Organic-inorganic hybrids
High-Barrier StrategiesHigh-Barrier Strategies
Y. Leterrier - SwissLaser Net Workshop, Basel, June 25, 2008
Why organic-inorganic hybrids?Why organic-inorganic hybrids?
Pluddemann, Silane Coupling Agents, Plenum Press (1990) Zinck et al., J. Mater. Sci. (1999).Haas et al., Surf. Coat. Technol. (1999)Bouchet et al., Surf. Coat Technol. (2005)
Substrate
Coating
Flaw
Highlycrosslinked
region
Chemisorbedlayers
Physisorbedlayers
Organo-silanes reduce the severity of superficial defects (‘Griffith flaws’)
R—Si—(OR’)3
7
Y. Leterrier - SwissLaser Net Workshop, Basel, June 25, 2008
NH2 Si(OC2H5)3
Gamma-aminopropyltriethoxysilane(γ-APS, Silquest A-1100TM)
1 - 20 %wt γ-APS/ethanolpH=11.4 and pH=8 (acetic acid)
oligomerization: 12 h at 60°C10 - 500 nm thick silane films
Spin coating on SiOx/PET films1000 rpm, 20 s
Magni et al, J. Phys. D (2001)Bouchet, Leterrier et al., Surf. Coat. Technol. (2005, 2007)
SiOx 12 nm PECVD from O2 dilutedHMDSO on 12 µm thick PET web
OTR ~ 2.1 cm3/m2/day/barCOS ~ 3.5%
Processing of Processing of organosilane-silica organosilane-silica hybridshybrids
Y. Leterrier - SwissLaser Net Workshop, Basel, June 25, 2008
Amino-silane treatmentreduces the size and
population of macro-defects
SiOx/PET RIE 12 min.Average defect radius 720 nm
γ-APS/SiOx/PET RIE 12 min.Average defect radius 330 nm
Singh, Leterrier et al., Surf. Coat. Technol. (2007)
Defect analysis in Defect analysis in organosilane-silica organosilane-silica hybridshybrids
8
Y. Leterrier - SwissLaser Net Workshop, Basel, June 25, 2008
Crack onset strain > 6%
Rochat et al. Thin Solid Films (2003)
Crack onset strain 3.5%
Mechanical integrity of Mechanical integrity of organosilane-silica organosilane-silica hybridshybrids
γ-APS/SiOx/PET
5 µm12%
5 µm20%
5 µm10%
0% 5 µm
10 nm SiOx/PET reference
0% 5 µm
Y. Leterrier - SwissLaser Net Workshop, Basel, June 25, 2008
Supertough Supertough high barrier high barrier encapsulationencapsulation
Supertough high barrier encapsulation
BIF > 105
nanolaminates Organic-inorganic hybrids
COS ~ 5%
Stress state?Microcracking?
9
Y. Leterrier - SwissLaser Net Workshop, Basel, June 25, 2008
Origin of stress in polymer coatingsOrigin of stress in polymer coatings
!(t) = 2 G(t)"c
"t0
t
# dt + 2 G($s+
Tc
Tf
#"c
"T)dT
Cureshrinkage
stress
Thermal stress(small for UV-
curable polymers)
Lange, Månson et al., Polymer (1995, 1997); Payne (1998)
… Lack of dimensional stability
… Void formation?
… Buckling and cracking
Y. Leterrier - SwissLaser Net Workshop, Basel, June 25, 2008
Towards low stress encapsulationTowards low stress encapsulation
Tailored processtemperature cycles
‘Low profile’ additives Radiation curing… Hyperbranched polymers
A low-stress material combines:
reduced shrinkage⇒ radiation curing
retarded modulus build-up⇒ hyperbranched polymers
10
Y. Leterrier - SwissLaser Net Workshop, Basel, June 25, 2008
Tg: 68°C Tg: 126°C
Tg: 28°C
Photoinitiators:1-Hydroxy-cyclohexyl-phenyl-ketone1:1 blend of 1-Hydroxy-cyclohexyl-phenyl-ketone and benzophenone
HBP + 5 vol% SiO2
100 nm
HBP + 20 vol% SiO2
100 nm
Low Stress UV Curable Low Stress UV Curable Hyperbranched Hyperbranched Polymer Polymer NanocompositesNanocomposites
Y. Leterrier - SwissLaser Net Workshop, Basel, June 25, 2008
Microbattery, layer thickness 500 µm
3
0.5
0.5
Fabricationtime(h)
372511250SU-8
7334.53.3500Polyester HBP
54542.47.7850Polyether HBP
FOMResidualstress(MPa)
Aspectratio, AR
Layerthickness, L
(µm)
Resist
SU8Polyether HBP
FOM = (L x AR) / (Stress x Fab_Time)
Jin Y.-H., J. Micromech. Microeng., 17, 1147-1153 (2007).Schmidt et al., J. Micromech. Microeng. 18, 045022 (2008).
Low Stress UV Curable Low Stress UV Curable Hyperbranched Hyperbranched Polymer Polymer NanocompositesNanocomposites
11
Y. Leterrier - SwissLaser Net Workshop, Basel, June 25, 2008
Polymersubstrate
Inorganic film(10-1000 nm)
BIF ~ 100COS ~ 2%
BIF > 105
COS ~ 1%
Barrier Improvement Factor: BIF = Ps/P
nanolaminates
Organic-inorganic hybrids
High-Barrier StrategiesHigh-Barrier Strategies
BIF ~ 1000COS ~ 2%
BIF ~ 1000COS ~ 5%
Y. Leterrier - SwissLaser Net Workshop, Basel, June 25, 2008
AcknowledgementsAcknowledgements
• F. Demarco, G. Rochat, B. Singh, J. Bouchet, J.-A. Månson, LTC-EPFL• Dr. J. Andersons, Inst. Polymer Mechanics, Riga (LV)• Dr. Y.-H. Jin, Pr. YH Cho, KAIST (KR)• Dr. P. Bouten, Philips Research Laboratories (NL)• Dr. N. Rutherford, Vitex Systems (USA)• Dr. D. James, Dr. S. Lundmark, Perstorp SC (S)• Dr. P. Fayet, Tetra Pak Suisse SA, Plasma Technology (CH)• Centre Interfacultaire de Microscopie Electronique (CIME-EPFL)• Centre de Micro-Nano-Technologies (CMI-EPFL)• Swiss Commission for Technology and Innovation (CTI) and the Top Nano 21 Swiss
initiative (TNS 5940.2)• Swiss National Science Foundation (SNF 200020-111706)• Swiss Federal Office for Education and Science (OFES - IST-2001-34215)• FLEXIDIS (EU-IST 2004-4354)
THANK YOU!