1. Overview of MEMS and Microsystems- uNIT1

2. WHAT IS MEMS? MEMS = Micro Electro Mechanical System
Any engineering system that performs electrical and mechanical functions
with components in micrometers is a MEMS. (1 μm = 1/10 of human hair)
Available MEMS products include:
● Micro sensors (acoustic wave, biomedical, chemical, inertia, optical,pressure, radiation, thermal, etc.)
● Micro actuators (valves, pumps and microfluidics; electrical and optical relays and switches; grippers, tweezers and tongs; linear and rotary motors, etc.)
● Read/write heads in computer storage systems, Inkjet printer heads.
● Micro device components (e.g., palm-top aircrafts, minirobots and toys, micro surgical and mobile telecom equipment, etc.)

3. HOW SMALL ARE MEMS DEVICES?
They can be of the size of a rice grain, or smaller!
Two examples:
- Inertia sensors for air bag deployment systems in automobiles
- Microcars

4. Inertia Sensor for Automobile “Air Bag” Deployment System
Courtesy of Analog Devices, Inc)

5. Micro Cars
Rice grain
(Courtesy of Denso Research Laboratories, Denso Corporation, Aichi)

6. There has been increasing strong market demand for: “Intelligent,”
MINIATURIAZATION – The Principal Driving Force
for the 21st Century Industrial Technology
There has been increasing strong market demand for:
“Intelligent,”
“Robust,”
“Multi-functional,” and
“Low-cost” industrial products.
Miniaturization is the only viable solution to satisfy such market demand

7. Miniaturization is ideal for precision movements and for rapid actuation.
Miniaturized systems encounter less thermal distortion and mechanical vibration due to low mass.
Miniaturized devices are particularly suited for biomedical and aerospace applications due to their minute sizes and weight.
Small systems have higher dimensional stability at high temperature due to low thermal expansion.
Smaller size of the systems means less space requirements. This allows the packaging of more functional components in a single device.
Less material requirements mean low cost of production and transportation.
Ready mass production in batches

8. Micro pressure sensors
MEMS as a Microsensor
Power
Supply
Micro
Input
Signal
Sensing
Transduction
Unit
Output
Signal
Element
Micro pressure sensors

9. MEMS as a Microactuator- motor
Power
Supply
Output
Micro
Actuating Transduction
Element Unit
Action
Rotor
Torque
Transmission
Gear
Stators
Micro motor produced by a LIGA Process

10. Components of Microsystems Microsystem Power Supply Signal
Transduction &
Processing Unit
Sensor
Actuator
Microsystem

11. Unique Features of MEMS and Microsystems
• Components are in micrometers with complex geometry
using silicon, si-compounds
and
polymers:
A micro gear-train by
Sandia National Laboratories
25 µm

12. SignalConditioner& Processor
Microsystems -
Micromechatronics systems
Intelligent
Package on a single “Chip”
Sensing /actuating
Mems
INPUT:
Desired Measurements or
functions
SignalConditioner& Processor
Transduction unit
OUTPUT:
Measurements
or Actions
Controller
Actuator
Signal
Processor
Comparator Measurements

13. Micro Sensors Vs MicroActuators
Acoustic wave sensors
Biomedical and biosensors
Chemical sensors
Optical sensors
Pressure sensors
Stress sensors
Thermal sensors
Micro Actuators:
Grippers, tweezers and tongs
Motors - linear and rotary
Relays and switches
Valves and pumps
Optical equipment (switches, lenses, mirrors, shutters, phase modulators, filters, waveguide splitters, latching & fiber alignment mechanisms)

14. Microsystems Microsystems =
sensors + actuators+ signal transduction
Microfluidics, e.g. Capillary Electrophoresis (CE)
Microaccelerometers (inertia sensors)

15. Microelectronics Comparison of Microelectronics and Microsystems
Microsystems (silicon based)
Primarily 2-dimensional structures
Complex 3-dimensional structure
Stationary structures
May involve moving components
Transmit electricity for specific electrical functions
Perform a great variety of specific biological, chemical,
electromechanical and optical functions
IC die is protected from contacting media
Delicate components are interfaced with working media
Use single crystal silicon dies, silicon compounds, ceramics and plastic materials
Use single crystal silicon dies and few other materials, e.g. GaAs, quartz, polymers, ceramics and metals
Fewer components to be assembled
Many more components to be assembled
Mature IC design methodologies
Lack of engineering design methodology and standards
Complex patterns with high density of electrical circuitry over substrates
Simpler patterns over substrates with simpler electrical circuitry
Large number of electrical feed-through and leads
Fewer electrical feed-through and leads
Industrial standards available
No industrial standard to follow in design, material selections, fabrication processes and packaging
Mass production
Batch production, or on customer-need basis
Fabrication techniques are proven and well
documented
Many microfabrication techniques are used for
production, but with no standard procedures
Manufacturing techniques are proven and well documented
Distinct manufacturing techniques
Packaging technology is relatively well established
Packaging technology is at the infant stage
Primarily involves electrical and chemical engineering
Involves all disciplines of science and engineering

16. Physics & Biochemistry
The Multi-disciplinary Nature of Microsystems
Natural Science:
Physics & Biochemistry
Engineering
Electrochemical
Quantum physics
Solid-state physics
Scaling laws
Material
Science
Processes
Mechanical Engineering
• Machine components design
• Precision machine design
• Mechanisms & linkages
• Thermomechanicas:
(solid & fluid mechanics, heat transfer, fracture mechanics)
• Intelligent control
• Micro process equipment design and manufacturing
• Packaging and assembly design
Materials Engineering
• Materials for substrates
& package
• Materials for signal mapping and transduction
• Materials for fabrication processes
Electrical Engineering
• Electric systems for
dynamics and
• Electric circuit design
•Integration of MEMS
and CMOS
• Power supply
electrohydro-
signal transduction
Chemical Engineering
• Micro fabrication processes
• Thin film technology
Industrial Engineering
• Production control
• Process design
• Micro assembly

17. MEMS in Automotive Industry
(6)(1)
(4)
(3)
(2)
(10)
(5)
(9)
(8)
(1) Manifold or Temperature manifold
absolute pressure sensor
(2) Exhaust gas differential pressure sensor
(3) Fuel rail pressure sensor
(4) Barometric absolute pressure sensor
(5) Combustion sensor
(6) Gasoline direct injection pressure sensor
(7) Fuel tank evaporative fuel pressure sensor
(8) Engine oil sensor
(9) Transmission sensor
(10) Tire pressure sensor

18. Silicon Capacitive Manifold Absolute Pressure Sensor

19. Application of MEMS and Microsystemsin
Aerospace Industry
Cockpit instrumentation.
Wind tunnel instrumentation
Microsattellites
• Sensors and actuators for safety –
e.g. seat ejection
• Sensors for fuel efficiency and safety
Command and control systems with MEMtronics Inertial guidance systems with microgyroscopes, accelerometers and fiber optic gyroscope. Attitude determination and control systems with micro sun and Earth sensors.
Power systems with MEMtronic switches for active solar cell array reconfiguration, and electric generators
Propulsion systems with micro pressure sensors, chemical sensors for leak detection, arrays of single-shot thrustors, continuous microthrusters and pulsed microthrousters
Thermal control systems with micro heat pipes, radiators and thermal switches
Communications and radar systems with very high bandwidth, low-resistance radio-frequency switches, micromirrors and optics for laser communications, and micro variable capacitors, inductors and oscillators.

20. Application of MEMS and Microsystemsin
Biomedical Industry
Disposable blood pressure transducers:
Lifetime 24 to 72 hours; annual production 20 million units/year, unit price $10
Catheter tip pressure sensors
Sphygmomanomet ers
Respirato rs
Lung capacity meters
Barometric correction instrumentation
Medical process monitoring
Kidney dialysis equipment
Micro bio-analytic systems: bio-chips, capillary electrophoresis, etc.

21. Application of MEMS and Microsystemsin
Consumer Products
Scuba diving watches and computers
Bicycle computers
Sensors for fitness gears
Washers with water level controls
Sport shoes with automatic cushioning control
Digital tire pressure gages
Vacuum cleaning with automatic adjustment of brush beaters
Smart toys

22. Telecommunication Industry
Application of MEMS and Microsystems
in the
Telecommunication Industry
• Optical switching and fiber optic couplings
• RF relays and switches
• Tunable resonators
Microlenses:
Microswitches:

23. Micro Optical Switches
2- Dimensional
3- Dimensional