Micro and Smart Systems
Course coordinators
1. G.K. Ananthasuresh , Mechanical Engineering ,IISc
[email protected]
2. K.J. Vinoy, Electrical Communications Engineering, IISc,
[email protected]
3. S. Gopalakrishnan, Aerospace Engineering, IISc ,
[email protected]
4. K.N. Bhat, Electrical Communications Engineering, IISc.
[email protected]
Prof.K.N.Bhat, IISc Bangalore
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Lecture Modules
Module 1: Introduction - Lectures 1 to 6
Module 2: Microfabrication processes –Lectures 7 to 14
Module 3: Mechanics of Solids - Lectures 15-24
Module 4: Finite element method – Lectures 25 to 30
Module 5: Electronics and packaging - Lectures 31 to 40
Prof.K.N.Bhat, IISc Bangalore
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Text / References
1) S.D. Senturia, Microsustem Design, Kluwer
Academic Publishers, 2001
2) Tai-Ran Hsu, MEMS & Microsystems Design and
Manufacture, McGraw Hill, 2002
3) V.K. Varadan, K.J. Vinoy, and S. Gopalakrishnan,
Smart Material Systems and MEMS: Design and
Development Methodologies, Wiley, 2006
Suggested hyperlinks
http://www.memsnet.org/mems,
/http://www.analog.com/en/mems-andsensors/products/index.html
http://web.mit.edu/microsystem-design/www/
Prof.K.N.Bhat, IISc Bangalore
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Suggested Additional Readings
1) G.T.A. Kovacs, Micromachined Transducers
Sourcebook, WCB McGraw-Hill, 1998
2) J.W. Gardner, Microsensors: principles and
applications, John Wiley & Sons, 1994
3) M. Madou, Principles of Microfabrication, CRC
Press, 1998
Prof.K.N.Bhat, IISc Bangalore
4
Micro and Smart Systems
Lecture -1
Glimpses of Microsystems and Miniaturization
Prof K.N.Bhat,
ECE Department , IISc Bangalore
email: [email protected]
Prof.K.N.Bhat, IISc Bangalore
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What are MEMS and Micro Sytems?
• Micro Electro Mechanical Systems (MEMS ) are
devices that have static or movable components
with some dimensions on the scale of microns
• MEMS combine microelectronics and micromechanics, and sometimes micro-optics
They are referred by different names in different
countries
MEMS : USA
MicroSystems Technology (MST): Europe
Micromachines : Japan
Smart materials and Smart Structures: India
Prof.K.N.Bhat, IISc Bangalore
6
Micro Electro Mechanical Systems (MEMS) - Microsystems
This is a Revolution similar to
VLSI in Microelectronics
Deals with
1. Miniaturization and batch processing of
Sensors , Actuators and microstructures
2. Integration of mechanical components with
electronics
Prof.K.N.Bhat, IISc Bangalore
7
Batch Processing and miniaturization
Cost Reduction
Batch Processing
Miniaturization
Reliability &
Reproducibility
•Low Power operation
• Biomedical and
aerospace Applications
Prof.K.N.Bhat, IISc Bangalore
8
Miniaturization approaches
• Conventional Micromachining
•Silicon Micromachining
Prof.K.N.Bhat, IISc Bangalore
9
Conventional Micromachining Techniques
• Each component must be made piece by piece. Low
price for large production volumes are the result of
mechanization.
• Ultrasonic machining, sandblasting, laser ablation and
spark erosion have aided in miniaturization.
• Finest details that can be machined are one to two
orders larger than what photolithography makes
possible.
Prof.K.N.Bhat, IISc Bangalore
10
Silicon Micromachining
• Suitable for batch processing similar to
fabrication of ICs.
• Production costs of whole production is
independent from number of components
fabricated.
• Miniaturization with finest details in the range
of 0.1 to 10m possible based on photo-lithography
Prof.K.N.Bhat, IISc Bangalore
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Classification of MEMS
MEMS structures and devices can be classified into
four major groups:
• Passive (nonmoving) structures (eg) microtips
• Sensors, which respond to the world, (eg) pressure
• Actuators (reciprocal of the sensors), which use
information to influence something in the world.
(eg) pump, valve etc
• Micro-Systems that integrate both sensors and
actuators to provide some useful function
Prof.K.N.Bhat, IISc Bangalore
12
MEMS Categories and Application areas
Application
Areas
Transportation Communications Analytical &
Medical
Categories
MEMS
Infrared
Structures Imagers
Optical & RF
Signal Guides,
Field Emission
Arrays
Pressure ,
MEMS
Sensors13 Acceleration,
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& Angular
Rate
MEMS
Aerodynamic
Actuators Flow
Control13
Micro Filters,
Micro
Channels
& - Mixers
Gas sensors
Acoustic
sensors
Displays, Optical Micro-pumps
switches, & RF
& -Valves
Switches &
Prof.K.N.Bhat,
IISc Bangalore
13
Filters
Transducers
Sensors
Convert
Measured Quantities into
Electrical Signal
Pressure sensor,
Accelerometer, Gyro,
Temperature Sensor, Gas
sensor, Flow sensor
Actuators
Convert different types
of energy into
Mechanical Energy
Micropump, RF
switches and
Resonators, micro
mirror, ES comb drive
Structures AFM tip, Field Emission Arrays,
Micro-fluidic Channels
Prof.K.N.Bhat, IISc Bangalore
14
Some Examples of Micromachined
Miniaturized Mechanical component
Micropump
Pressure
sensors
RF filters
Micro
cantilevers
(DNA Sensor)
r 
k
m
Micro
Acceleration
Sensors
F  ma  kx
Nano- tip for
AFM and for
FEA
Prof.K.N.Bhat, IISc Bangalore
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Need for Miniaturization of Sensors
1.Intracranial Pressure (ICP) and blood pressure monitoring
3.Oceanography-CTD sensor
for Marine Engg (NPOL , Kochin)
2.Mapping pressure on
LCA wing
4. Air pressure and flow in the
ignition system of automobile
Prof.K.N.Bhat, IISc Bangalore
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Piezoresistive pressure sensor
Pressure P
Diaphragm
R1  R2  R3  R4  R
Piezo resistors : p-type
boron diffused/ implanted
R
Vo  Vin
R
 Vo
Sensitivity S 
Prof.K.N.Bhat, IISc Bangalore
P
17
Motorola’s Manifold-absolute Pressure
(MAP) Sensor and schematic of its package
Prof.K.N.Bhat, IISc Bangalore
18
Silicon cantilever beams for detection of DNA
An array of cantilevers treated
with different strands of DNA.
When a solution containing
different fragments of DNA is
introduced, complementary
strands of DNA will naturally
bind to specific cantilevers
creating stress which deflects the
cantilever.
Can detect damaged DNA
sequences, since a single base
mismatch will cause a slightly
different stress, indicating the
presence of a damaged fragment.
A hybrid micromachine
Prof.K.N.Bhat, IISc Bangalore
/DNA system (IBM,Zurich)
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Need for Miniaturization of structures
Microstructures
Micro geras
Field emission tips for high frequency
Vacuum Electron Devices
Micro turbine
Nanometer
size AFM Tip
Prof.K.N.Bhat, IISc Bangalore
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Need for Miniaturization of Actuators
Micropumps for l/minute pumping
(1) Drug delivery drug dosage control
(2) Lubricating bearings of gyro motor space appln.
Actuation
Mechanism
Pump Diaphragm
Pump Chamber
Outlet Valve
Inlet Valve
Inlet
Valve Threshold
Pressure p (crit)
Outlet
Stroke Volume
V
Chamber Pressure p
Chamber Volume Vo
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Prof.K.N.Bhat, IISc Bangalore
Microsystems and Miniaturization
Miniaturization is important for Applications
• Biomedical : pressure sensors (Intra Cranial Pressure,
blood pressure) ), cantilever beams (DNA analysis),
micropump ( controlled micro dose of drug Delivery)
• Aerospace and Automobile: Pressure sensors ,
accelerometers,
• Space programs: Pressure sensors , accelerometers,
gyro, micropump
• Micro fluidics channels and mixers: Chemical analysis
and synthesis and lab on Chip concept
• Defense : Explosive detection, gas sensors, pressure
sensors , accelerationProf.K.N.Bhat,
sensorsIIScand
RF MEMS
Bangalore
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