MSE 542. Flexible Electronics. Lecture 1. Tuesdays, 1:25 pm to 4:30 pm. Olin 245
.... Or What Do Electronic Devices Need To Do? • Chip/Circuit Protection.
MSE 542 Flexible Electronics Lecture 1 Tuesdays, 1:25 pm to 4:30 pm Olin 245
Example 1: Flexible Displays
• Flexibility enables new concepts in electronics
Example 2: Smart Bandage Antenna
Control Electronics and RFID Battery
Temperature Sensors
Gas Sensors Fluid Sensors Smart Biomedical Bandages
Simple processes enable low cost
What is Flexible Electronics? •
Flexible electronics “can be bent, flexed, conformed or rolled to a radius of curvature of a few centimeters without losing functionality”
• • • • • •
Thin profile Large area Conformal Flexible Wearable? Possibly manufactured roll-to-roll
Course Description • Flexible electronics holds the promise of transformative developments in: (1) flat panel lighting (low cost, low energy), (2) energy production systems (solar) and (3) infrastructure control and monitoring (sensing, energy control, hazard monitoring).
• Practical realization of flexible circuits will require
dramatic progress in new materials that are compatible with flexible media and amenable to facile and low temperature processing as well as major advances in manufacturing technologies such as roll-to-roll processing.
• This course will discuss these and other developments. • Lecturers will come from Cornell, GE, IBM, EIT, Binghamton
Technology Convergence Makes Flex Possible • Thin film transistors • Active matrix • Conducting layers • Plastic, glass and metal substrates • Barrier layers • New deposition methods
Why is This Topic so Exciting? •
Flexible electronics, if low cost enough, means that we can give electronic attributes to everyday objects
•
Imagine displays that roll up and fit in your pocket
•
Imagine solar panels are your clothes or the fabric is a sensor net
•
Imagine light sources you hang like a picture on a wall
Examples
• Flexible Displays • Flat Panel Lighting • Solar Cells • RFID Tags • Smart Bandage
Electronics go everywhere
Sony eReader Pioneer
e-Ink & Lucent
Electrolux
RFID • Imagine a carton of milk with RFID tag
• Refrigerator will tell you
when it is out of date or used up
• Will be used to track
inventory of most retail items
• Where will it end up?
Alien Technology
Organic light emitting diodes (OLEDs) Pioneer (1997)
Kodak (2004)
Sony (2004)
Motorola (2001)
Pioneer (2001 - demo)
OLEDs vs. Liquid Crystals
OLEDs for lighting
GE
Organic thin film transistors (OTFTs) All-polymer integrated circuits (Philips, 1998).
Electrolux
OPVs Solar Cells for energy production Solaronix Sustainable Technologies International
Class Expectations • There will be problem sets approximately every two weeks. • There will be a class prelim. • There is NO FINAL, but there is a term paper due during study week. – The topic will be selected in conjunction with the course instructor.
• 30% Homework • 30% Prelim • 40% Final Term Paper
Seminar Series will hold a separate seminar series • We starting mid-way through the semester speakers are leaders of the • Distinguished developing flexible electronics community coming from industry and academia
at seminars will be greatly • Attendance encouraged, but is optional
Texts • Flexible Flat Panel Displays (Wiley Series in Display Technology) (Hardcover) – – – –
by Gregory Crawford (Editor) Hardcover: 556 pages Publisher: John Wiley & Sons (June 21, 2005) ISBN: 0470870486
• Principles of Electronic Packaging – – – –
by Donald Seraphim, et al. Hardcover: 962 pages Publisher: McGraw-Hill College (March 1, 1989) ISBN: 0070563063
Silicon Run Video video shows where flexible electronics • This comes from, factors to consider is important to see what flexible • Itelectronics is evolving from and to
understand that today these are not yet competitive areas
as small, not as fast, but enabling new • Not uses and concepts to be realized
Break & Discussion • What did video show? • Showed chip processing - now we need to consider “packaging”
• Adjustments to get higher performance • Used to be considered less important, but now
package is bottleneck in many electronics if not done right
• Advances in packaging are basis of new flexible electronics!
Other Ideas? • environmental sensors • make inanimate devices active - e.g. furniture, rooms, etc.
• tag everything - passports • biomedical implants - connect the nervous system to the external world
What skills do we need? •
Flexible electronics can be thought of as combination of microelectronics (albeit on larger scale) with electronic packaging
•
Need understanding of materials and electronics
• •
It is a new and developing area
•
Most of all we need imagination!
As such we will look at this from perspective of both these areas
What makes flexible different from current microelectronics?
• Thin form enables flexibility, BUT places additional demands on mechanical performance
• Normal protective packaging is too big, so new methods of protection are needed
• Speed is not essential • New methods of manufacture may enable
cost reduction, but compromise robustness
Course Instructors Prof. C. K. Ober, Cornell lead
• Dr. Poliks, EI lead • Prof. Baker • Prof. Giannelis • Prof. Malliaras • Prof. Thompson • Prof. Sammakia, BU • Dr. Obrzut, NIST
Dr. Calmidi, EI Dr. Chan, EI Dr. Egitto, EI Dr. Fillion, GE Dr. Korman, GE Dr. Magnuson, EI Dr. Matienzo, EI Dr. Wilcox, IBM
EI Corporate Profile " Over 40 Years experience in development and fabrication of leading edge technology " Incorporated as Endicott Interconnect in November 2002 " A tradition of technical invention " Facility - 1.3M sq feet manufacturing and lab space " Employment Fabrication Engineering Research & Development " Prototyping through volume production in three shift operation
Class Outline Jan. 24
Course overview: What is Flexible Electronics? (Ober)
Jan. 31
Design: Connectors and interconnects (Chan, EI; Wilcox, IBM)
Feb. 7
Technology Focus: Displays and lighting (OLEDs) (Malliaras)
Feb. 14
Performance: Electrical performance and characteristics (Obrzut, NIST)
Class Outline Feb. 21
Design: Single and multichip packages (Fillion, GE)
Feb. 28
Processing: Lithography and pattering (Ober)
March 7
Processing: Laser processing and via formation (Egitto, EI)
March 14
Design: Substrates and barriers (Poliks, EI; Giannelis)
March 28
The Flexics Story - History of a Startup (Thompson; Wickboldt, USDC)
Class Outline April 4
Technology Focus: Solar energy conversion (Korman, GE)
April 11
Processing: Metal deposition (Baker; Magnuson, EI)
April 18
Performance: Physical Analysis (Matienzo, EI)
April 25
Design: Future technologies (Chan and Lin, EI)
May 2
Design: Thermal management and reliability; Course Wrap-up (Calmidi, EI; Sammakia, BU; Ober)
What Is Packaging? Or What Do Electronic Devices Need To Do?
• Chip/Circuit Protection – Environmental, thermal, mechanical • Communication – Maximize I/O • Power • Heat removal - Forced or natural convection - Wiring structure and power interconnects
Packaging vs. Microelectronics • Rivals microelectronics in terms of industry size and complexity
• Critical bottleneck in device speed • Sets size and capability of electronic device • Determines cost of device
The Package
Each level needs to meet goals of package!
Levels of Packaging • 1st Level – chip on substrate • 2nd Level – card • 3rd Level – card on board – packaging getting as sophisticated as microcircuit – how will we categorize package for flex?
Packaging Technologies
New Technologies Needed for Flex • Materials selection • Circuits on substrate • Processing conditions and limits
Conductors
Fewer conductors to choose from
Insulators
Largely organics
2nd-Level Packages (How would they function for flex?)
Single Chip Packages
Chip Package • Die attach • Wire bonding & Plating • Encapsulation - molding compound
• Package types • Quad flat pack • PLCC • PGA • BGA • C4
Multichip Modules • Combine several chips in one package
• Reduces signal delay time • Heat dissipation • Stress relief • Substrate is high signal density layer
Types MCM-L MCM-C TCM
Tape Automated Bonding (TAB) • Attach chip to plastic
carrier with metallization
• Looks like 35 mm film • Speeds up production • Usually polyimide & copper
• Flex circuits use similar technology
PCB or PWB
• Composite - often epoxy/glass • Parallel process • Screen printing • Lamination • Multilayer crossed by vias inductance and • Capacitance, resistance • Pick and place • Solder & reflow • Thermal issues
Common Themes
(Flex will have to achieve this)
• Maximize I/O • Minimize thermal issues • Heat dissipation • Thermal stress • Environmental protection and encapsulation • Lowest cost needed to get results • Drive to continuously reduce size and power
Microelectronics Advanced Interconnections Semiconductors versus Package Smallest features: “parallel paths” for how long?
Meso
Micro
PWB
Interconnect Gap
PWB w/ buildup layers & Laser vias HyperBGA® Interconnect technology Z-interconnect technology
IC scaling
$
Nano Source: adapted after Shipley
1990’s
2000’s
Reduced Interconnect Gap
2010’s
Time
SOP
Laser via / thin film / z-interconnect based interconnect technology needed to reduce the IC to PWB interconnect gap HyperBGA is a registered trademark of Endicott Interconnect Technologies, Inc.
Endicott © 2005 Endicott Interconnect Technologies, Inc.
Interconnect
Integrated Systems Technology Evolution Embedded Actives Optical Interconnect
Function -- Density
Flexible Substrates Embedded Passives Electrical Interconnect HyperBGA Integrated Optical, Passives
Organic z-interconnect
Enhanced Thermal and Power Management Integrated Flex, Optical, Passives & Actives
Integrated RF
5
10
20005
2005-10
© 2005 Endicott Interconnect Technologies, Inc.
20
40
2010-15
2015-20
Data Rate Gb s-1 Time
Endicott Interconnect
Flexible Electronics: Enabling Materials
• Flexible substrates • Barrier layers conducting layers and mechanical • Inorganic properties conducting layers and mechanical • Organic properties
• Optical coatings • Thin film transistors • Electro-optic materials
Enabling Processes
• Patterning Methods • Printed organic electronics • Rollable materials • All plastic systems
Flexibility • Flexibility creates potential problems as the multilayer film is flexed
• Different E • Different CTE
Stress Cracking
Modulus mismatch leads to stress cracking
Mechanical Properties of Layer Components Material
Young’s modulus, E (GPa)
Coefficient of Thermal Expansion, CTE (ppm/K)
Hardcoat
6.0 ± 0.5
61 ± 1
Base polymer
2.9
~65
Gas Barrier
150
10
ITO
119 ± 5
7.6
Organic Substrates
Flexible plastics are not as thermally stable as glass or metal
New Semiconductors
Polymers can be used a semiconductors and even doped to be conductors
TFT’s
• TFT’s on flexible substrates can be produced from polymeric or inorganic semiconductors using printing methods
Barrier Layers
• Barrier layers are needed to protect the
various components from the environment
New Patterning Methods
• New processing is enabled by new materials
Future Prospects
• Future applications not even imagined do not appear here
The U.S. Early Adopter for Flexible Displays
The Air Force has announced a complementary program using OLED on SS Source: John Pellegrino (ARL) and Darrel Hopper (AFRL)
Flexible Display Center @ ASU Limited Quantities INDUSTRY
Flexible Display Center of Excellence
of Display Demos
UNIVERSITIES
United States Army GOVERNMENT LABS/RDECs Technology into Center
Technology subsets from the Center (i.e. backplanes)
Roll-to-Roll Manufacturing R&D Motivation and Purpose A proposed means to lower the cost of producing flexible displays in a high-volume manufacturing environment by taking advantage of a unique attribute of flexible substrates relative to the traditional thick glass substrate used in LC displays. Such a manufacturing paradigm, compared to the traditional batch process (cluster tools and cassette transport), generally does not enable any enhanced product performance characteristics.
What is Roll-to-Roll (R2R)? Plastics
Steel
D L
T
“Web”
• Substrate is a Flexible format • L>>W>>T • Can be stored in coils (D
