ESH Challenges and Opportunities in
Large Area High Tech Manufacturing:
Displays, Thin Film Photovoltaics, Solid
State Lighting, and Flexible Electronics
Greg Raupp
Chemical Engineering Program
Arizona State University
+1-480-727-8752
raupp@asu.edu
CEBSM Tele-seminar June 11, 2009
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Principal Takeaways
● ESH manufacturing challenges in the maturing flat panel
display industry and the emerging thin film photovoltaic,
solid state lighting and flexible electronics industries are
strikingly similar to those encountered in microelectronics
manufacturing
● Philosophies, approaches and techniques successfully under
development or adopted in the semiconductor industry can
be leveraged to achieve success
● Large area manufacturing industries produce products
where 30-50% of the manufacturing cost is in the materials
 substantial opportunity for green benefit for fab
processes with higher materials utilization efficiency and/or
reduction of steps
CEBSM Tele-seminar June 11, 2009
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Representative FPD Industry Thinking
(Source: www.cmo.tw)
CMO's Green Operations … plan for 2011 has been
specifically conceived to meet the following goals:
● Implementation of 9 major initiatives in greening
operations: Energy conservation, material conservation,
recyclability, low toxicity, health-oriented, systems, water
conservation, carbon emissions reduction, resource
recycling
● 90% reduction in PFC greenhouse gases and NF3 emissions
● Increase in the waste resource recycling rate to 93%
● Reduction in water and electricity use per unit area to 90%
of current levels (2008)
CEBSM Tele-seminar June 11, 2009
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Display Glass Manufacturing
Generations
Gen 10 = 2850 x 3050 mm
(2010)
(March 2006) Corning announced the commercial launch of Eagle
XG, the first LCD glass substrate free of all heavy metals, including
arsenic … is also free of antimony, barium, and halides … that can
produce potentially harmful manufacturing by-products.
CEBSM Tele-seminar June 11, 2009
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Display Technology Types
• Light Emitting Displays
• Light Transmitting Displays (light valves)
• Light Reflecting Displays
Emissive
(OLED)
CEBSM Tele-seminar June 11, 2009
Transmissive
with Backlight
(LCD)
Reflective
(EPD)
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Active Matrix Displays
SVGA
Super Video Graphics Array
Array of 800 x 600 pixels
Pixels
Gate
Line
Source Line
TFT
Capacitor
Dimensions
Pixels: tens of microns
Thin Film Transistors: several microns
Single Pixel
with 3 sub-pixels
RGB
CEBSM Tele-seminar June 11, 2009
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a-Si:H TFT Fabrication
PECVD a-SiNx:H
IMDs
PECVD n+ a-Si:H contact
PECVD a-Si:H Channel
Sputtered metallization
Sputtered ITO
Substrate
Sputtered metal gate
•
•
•
•
PECVD a-SiNx:H
gate dielectric
Patterning by conventional photolithography
3-5 masks for a-Si:H TFT arrays
6-7 masks for poly-Si TFT arrays
Color Filter Arrays (CFAs) are also fabricated through
conventional photolith processes
CEBSM Tele-seminar June 11, 2009
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Large Area a-Si:H Production
Systems
•
•
•
•
AKT PECVD Cluster Tool
a-Si / a-SiNx / n+ a-Si
GEN II 370 x 470 mm to GEN 8
2.2 x 2.5 m glass substrates
Total worldwide areal capacity
increased 250% over last 3
years to 25 MSF
CEBSM Tele-seminar June 11, 2009
•
•
•
•
Applied SunFabTM Thin Film PV
Production Line
mc-Si / a-Si PECVD
5.7 m2 glass substrates
Planned turnkey plants will
represent dramatic increase in
worldwide areal capacity
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NF3 Emissions a Growing Concern
Measured and modeled atmospheric NF3 concentrations
and trends from 1978 to 2008. Northern Hemisphere
NF3 measurements are shown as filled circles, together
with the spline curve Northern Hemisphere trend (solid
line) fitted to these measurements. The modeled
Southern Hemisphere trend and modeled global mean
trend (dotted line) are shown as dashed and dotted lines,
respectively. Southern Hemisphere measurements are
plotted as filled squares. Click to enlarge.
“This rise rate corresponds to about 620
metric tons of current NF3 emissions
globally per year, or about 16% of the
poorly-constrained global NF3
production estimate of 4,000 metric tons
per year … a significantly higher
percentage than has been estimated by
industry (FPD, PV, Microelectronics),
and thus strengthens the case for
inventorying NF3 production and for
regulating its emissions.”
Source: Weiss et al., Geophys. Res Lett. (2008)
CEBSM Tele-seminar June 11, 2009
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Emerging Technology: Flexible Displays
Reflective
Electrophoretic Displays
 Ultra-low power
 Sunlight readable
 Near-video rates
Click here to play EPD video clip
Emissive
Organic Light Emitting Displays
 Low power
 Vibrant full color
 Full motion video
Click here to play OLED video clip
Source: Flexible Display Center
at Arizona State University
CEBSM Tele-seminar June 11, 2009
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Beyond Flexible Displays
Macrotechnology  does not compete / replace Si-based devices;
instead complements in applications where Si CMOS is not well-suited
(new markets)
Macrotechnology Unique Attributes:
 Less is not Moore!  not driven by transistor downscaling (performance), instead driven by unique
integrated functionality and form factors
 Bigger is Better!  large area (as well as small)
applications
Sensors
(ASU)
Wearable
Devices
 Be Flexible!  compact, ultra-thin, rugged, lightweight,
implantable, wearable, conformable, and (potentially)
transparent
Flexible
Digital
Radiography
CEBSM Tele-seminar June 11, 2009
Inflatable
spacecraft and
extra-terrestrial
habitats
Flexible Solar
Cell
Phased-array
Antenna
Building-integrated PV and SSL
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Flexible Microelectronics and Display
Manufacturing Pathways
• Adapt existing plate-to-plate toolset infrastructure
 Free-standing flexible substrates
 Substrate fixturing / framing
 Backside thinning: chemical etch or grind-polish
 Substrate temporary bonding – debonding
 Substrate coat - release
 Layer transfer
• Adopt Roll-to-Roll manufacturing infrastructure
 Toolsets immature with significant issues –
handling, layer alignment, resolution, reliability
 Metrology strategy undefined
 Take step-wise “R2R-compatible” approach
focusing on critical issues
CEBSM Tele-seminar June 11, 2009
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Options with Existing Manufacturing Infrastructure
Bond - Debond
FDC SEC LG-D ITRI PV
Coat – Laser Release
IBM
Philips (EPLaR) PVI
Layer Transfer
Seiko-Epson (SUFTLA)
Sacrificial poly-Si
on Carrier
Substrate bonded with
Temporary Adhesive
to Carrier
TFT Fabrication
130 – 180 C
Spin-coated Polyimide
on Carrier
TFT Fabrication
300 – 380 C
TFT Fabrication
280 - 300 C
Temporary Substrate bonded
with Water-soluble Adhesive
Laser Release: Ablation
Triggered Debond:
Thermal
Solvent
Light
Mechanical
CEBSM Tele-seminar June 11, 2009
Laser Release:
Interfacial Melting
Bond to Flex then release
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Capability/Limitation Comparison
Capability/Limitation
Temp Bonding
EPLaR
SUFTLA
Flexible Substrate
High surface
quality polymer or
metal foil
Solution-castable
polymers (PI, BCB)
Any
TFT Process
Temperature Limit
Substratedependent
(180 C for HSPEN)
Polymerdependent
(280 C for PI)
Typical glassbased TFT limits
Flexible Substrate
Distortion
Can be significant
– but can be
controlled to
negligible level !
Negligible
Not applicable
Release Process
Rapid automated
dry
Laser interfacial
melting
Laser ablation
Scale-ability
?
?
?
CEBSM Tele-seminar June 11, 2009
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Temporary Bonding – Debonding:
Manufacturing Challenges
• Temporary bonding with semiconductor-grade
adhesive
 Compatible with Si-based TFTs
 Low total thickness variation (TTV)
 Defect (particle/bubble) free
 TFT and EO process flow and toolset compatible
• Automated de-bonding
 Triggered release (thermal, radiation, chemical,
mechanical)
 Residue-free
 TFT array and substrate (and carrier) damage-free
Complexity of component interactions requires system-level
substrate/barrier/adhesive/carrier/toolset solution
CEBSM Tele-seminar June 11, 2009
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Temporary Bonding Pitfalls
HS-PEN on Si
Blisters form at defect
(bubble, particles) sites
Exacerbated by
adhesive out-gassing at
temperature and in
vacuum
SS on Si
“Teacup” failure due to
CTE mismatch between
substrate and carrier
Adhesive viscoelasticity also crucial
CEBSM Tele-seminar June 11, 2009
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Effect of Bow on TFT Array Quality
SS Substrates
TFT Drive Current Array Maps
Original Materials
and Process
CEBSM Tele-seminar June 11, 2009
New Materials
and Process
3.8-in. QVGA EPD
Display Module
Low (Pilot Line)
defectivity
<0.01% point defects
0-5 line defects
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Evolutionary Approach to
Roll-to-Roll Manufacturing
CEBSM Tele-seminar June 11, 2009
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Towards Roll-to-Roll Manufacturing
• (Some) Critical Issues
o R2R incompatible processes (e.g., spin-on processes)
o Layer registration in photolithography
o Low defectivity handling including in-and-out-of vacuum
• Example Approaches
 Mist coating
 Imprint lithography with dry etch
 All printing process (fully additive, no vacuum)
CEBSM Tele-seminar June 11, 2009
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Large Area Mist Coater
High (> 90%) materials utilization efficiency
High uniformity (< 3% non-uniformity across panel)
Versatile: up to 4 materials; 0.5 to 15 mm films
High uptime and throughput
FDC Gen II System
Scaled by EVG to Gen 3.5 for Plastic Logic
CEBSM Tele-seminar June 11, 2009
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HP Self-Aligned Imprint Lithography (SAIL)
Circumvents Alignment-Distortion Issue
Imprint
Lithography:
Mask
removed
Stack
Top TFT
metal
etched
andthinned
down
n+
contact
toone
theone
etched to create
Exposed
Imprinted
Bottom
Then
undercut
metal
area
mask
etched
etch
tolowered
remove
down
to
from
Full
stack
with
imprinted
Imprint
mask
level
bottom
channel
metal
expose
level
under
tothinnest
expose
gate
contacts
parts
channel
of mask
polymer
mask
Photomask-free
Process
4 levels in 0.5 μm steps 
Multiple mask levels
Imprinted as single 3D structure
SAIL TFT
Etching Process
Imprint polymer
S&D metal Cr
Si contact
n+ uC
Si contact
a-Si:H
channel
a-Si
semiconductor
SiNx dielectric
Gate metal Al
Polymer
substrate
Plastic substrate
O. Kwon, et al., IMID 2007, Daegu, ROK
Compliments of Carl Taussig
HP SAIL-fabricated AM-EPD
on FDC thin film stack on HS-PEN
CEBSM Tele-seminar June 11, 2009
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Fully Additive Processing:
Inkjet Printing
Litrex 142
GEN II
Printer
Advantages
 Low Temperature
 Non-vacuum
 Fewer process steps
 High materials utilization
CEBSM Tele-seminar June 11, 2009
Challenges
 Alignment ( ±15 mm )
 Resolution (min. linewidth
30 mm)
 Manufacturability (yield,
throughput)
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Materials Requirements for Fully
Additive Printing Fabrication
• High performance functional materials
 Semiconductors
 Dielectrics
 Conductors
• In form of solutions, dispersions, melts
• Low temperature cureable
• Adherent
• Accurate linewidth and feature control
A. Arias, et al., Flexible
Displays and Microelectronics
Conference 2007, Phoenix, AZ
CEBSM Tele-seminar June 11, 2009
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Small Molecule OLED Vapor Deposition
Full Color RBG with Shadow-masking
Source: A. Chang, et al.,
Information Display 22(6),
20-22 (2006).
Source: S. Krishnamurthy, OLEDs Asia (2006).
Poor materials utilization efficiency
Low throughput
High COO
CEBSM Tele-seminar June 11, 2009
Sequential deposition
RGBW adds 4th step
No pixelation for white SSL but more
complicated stack
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Alternative OLED Approaches to
Enhance Materials Utilization
Other Approaches:
White smOLED with CF
Vapor jetting
Solution processing of polymer
OLEDs – several printing
approaches for pixelation
Source: S. Krishnamurthy, OLEDs Asia (2006).
High materials utilization efficiency
On demand vaporization: rapid response
and high throughput
CEBSM Tele-seminar June 11, 2009
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Conclusions
● ESH manufacturing challenges in the maturing flat panel
display industry and the emerging thin film photovoltaic,
solid state lighting and flexible electronics industries are
strikingly similar to those encountered in microelectronics
manufacturing
● Philosophies, approaches and techniques successfully under
development or adopted in the semiconductor industry can
be leveraged to achieve success
● Large area manufacturing industries produce products
where 30-50% of the manufacturing cost is in the materials
 substantial opportunity for green benefit for fab
processes with higher materials utilization efficiency and/or
reduction of steps
● Emergence of flexible electronics technology and migration
to R2R manufacturing provides unparalleled opportunity to
design green / sustainable solutions
CEBSM Tele-seminar June 11, 2009
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Acknowledgements
• ASU gratefully acknowledges the substantial financial
support of the U.S. Army through Cooperative Agreement
W911NF-04-2-0005
• We also gratefully acknowledge the FDC’s Members for their
technical and financial contributions to the Center
CEBSM Tele-seminar June 11, 2009
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FDC Team
CEBSM Tele-seminar June 11, 2009
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Thank You !
CEBSM Tele-seminar June 11, 2009
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