Mostafa Soliman, Ph.D. 1 MCT321: Introduction to Nano-Mechatronics Lecture #1: Introduction Mostafa Soliman, Ph.D.
Mostafa Soliman, Ph.D.
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MCT321: Introduction to Nano-Mechatronics
Lecture #1: Introduction
Mostafa Soliman, Ph.D.
Course Objectives
Course Contents
History of MEMS
Naming Terminology
Some MEMS Applications
Some MEMS Devices
Market Shares and Revenues
MEMS Technologies
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By the end of this course, the student should be able to:
• Identify fast growing areas in MEMS fields.
• Appreciate the advantages and challenges of building
electromechanical devices at the micro-scale.
• Recognize sensing and actuation mechanisms
applicable to MEMS.
• Understand the basic design and operation of MEMS
devices.
• Understand the major manufacturing technologies for
MEMS.
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o Introduction to MEMS
o MEMS Scaling Laws
o Microfabrication Processes
o Microfabrication Technology, Bulk micromachining
o Microfabrication Technology, Surface micromachining
o Micromachining Technology, Silicon On Insulator (SOI)
o MEMS Electromechanics, Microstructures
o MEMS Electromechanics, Damping
o Microactuators
o Capacitive actuation
o Thermal actuation
o Micro Sensors
o Applications.
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Final Exam: 40 %
Mid Term exam: 20%
Project: 25%
Attendance: 5%
Assignments: 10%
Quizzes: 10%
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MEMS is the second silicon revolution.
MEMS is fabricated by microfabrication technologies.
MEMS technology is a batch fabrication process,
same as ICs technology.
MEMS technology is mature, more than 25 years.
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Manufactured onto semiconductor material.
Used to make sensors, actuators,
accelerometers, switches, and light reflectors
Used in automobiles, aerospace technology,
biomedical applications, ink jet printers,
wireless and optical communications
Range in size from a micrometer to a
millimeter range.
Three MEMS blood pressure sensors
on a head of a pin
[Photo courtesy of Lucas
NovaSensor, Fremont, CA]
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On December 29th 1959, Dr. Richard Feynman,
from Caltech, presented a seminal talk, “There’s
Plenty of Room at the Bottom”.
In his talk, Dr. Feynman presented, motivated, and
challenged researchers with the desire and
advantages of exploring the small scale engineered
devices.
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Richard Feynman on his bongos Photo credit: Tom Harvey
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Some of Dr. Feynman comments:
Scaling of physical phenomena:
o “The effective viscosity of oil would be higher and higher in proportion as we
went down in size”.
o “Let the bearings run dry; they won’t run hot because the heat escapes
away from such a small device very, very rapidly”.
Miniaturizing the computer:
o “…the possibilities of computers are very interesting — if they could be
made to be more complicated by several orders of magnitude”.
o “For instance, the wires should be made 10 or 100 atoms in diameter, and
the circuits should be a few thousand angstroms across”.
Use of small machines:
o “…it would be interesting in surgery if you could swallow the surgeon. You
put the mechanical surgeon inside the blood vessel and it goes into the
heart and looks around”.
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Dr. Feynman’s challenges and rewards:
Dr. Feynman offered 2 prizes each of 1000 USD for the following achievements:
o Build a working electric motor no larger than a 1/64-in. (400-μm) cube.
o Print text at a scale (1/25,000).
As a result:
One year later, 1960, William McLellan, built a 250- μm, 2000-rpm electric
motor using 13 separate parts to collect his prize.
o This illustrated that technology was constantly moving toward miniaturization.
In 1985, T. Newman and R.F.W. Pease used e-beam lithography to print the first
page of “A Tale of Two Cities” within a 5.9-μm square.
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Mclellan/Feynman. Mclellan’s motor nest to pin head. Magnified model.
The first page of “A Tale of Two Cities” within
a 5.9-μm square by T. Newman and R.F.W.
Pease
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In Europe, these systems are called “Microsystems” or
“MST”.
In Japan, they are called “Micromachines”.
In the United States, and almost elsewhere, they are called
“Microelectromechanical Systems,” or “MEMS”.
“Microsystems” is more general, more inclusive, and in many
ways more descriptive.
“MEMS” acronym is catchy, unique, and is taking hold
worldwide.
But the MEMS concept has grown to encompass many other
types of small things, including thermal, magnetic, fluidic, and
optical devices and systems, with or without moving parts.
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Inertial Measurements: Accelerometers, gyroscopes, vibration sensors.
Pressure Measurements: TPMS (Tire Pressure Monitoring System) ,
disposable blood pressure sensors and various industrial applications.
Display Technology: Optical MEMS in projectors, plasma displays.
RF Technology: Tunable filters, RF switches, antennas, phase shifters,
passive components (capacitors, inductors).
Chemical Measurements: Micro-fluidics: Lab-On-Chip devices, DNA test
structures, micro-dispensing pumps, hazardous chemical and biological
agent detectors.
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3-axis accelerometer
3-axix gyroscope Module size
A conventional
gyroscopes
Unmanned planes
Missiles
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Ant Leg
Each mirror is about 17μm square!
DMD mirrors – complete DLP units have over 2 million mirrors – all functioning!
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Variable Optical Attenuators
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Scratch Drive Actuators (SDA)
SDAs push-pull a mirror
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How about Middle East!!!!
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Most MEMS devices and systems involve some form of
lithography-based microfabrication, borrowed from the
microelectronics industry and enhanced with specialized
techniques generally called “micromachining”. The batch
fabrication that characterizes the IC/MEMS industry
offers the potential for great cost reduction when
manufactured in high volume.
Bulk/Surface micromachining, LIGA, SOI, DRIE are the
most popular fabrication techniques for MEMS.
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Melting
point (°C)
Thermal
expansion
(10-6/°C)
Density
(g/cm3)
Young’s
modulus
(GPa)
Si 1415 2.5 2.4 130-169
SiN 1900 2.8 1.48 243
SiO2 1610 0.5 2.27 73
Al 660 25 2.70 70
Steel 1500-2000 12 7.9 210
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Custom Processes Standard Processes
• Surface or bulk micromachining.
• Any number of layers.
• Serves a certain research group.
• Expensive.
• Not commercial.
• Mainly for R&D only
• Surface or bulk micromachining.
• A specified number of layers.
• Multi-User processes, open for all
researchers and industries.
• Less expensive.
• Commercial.
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Background:
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Mechanical structures are fabricated by thin films deposited on the substrate
surface.
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Surface Micromachining:
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Surface Micromachining:
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Mechanical structures are fabricated inside the substrate itself.
Method to make
cantilevers
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Bulk Micromachining (wet etching):
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• SOI (Silicon On Insulator) is one of the most reliable MEMS microfabrication
processes.
• Combines both the simplicity in making moving devices along with device’s
performance complexity.
Carrier wafer
Structural wafer
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DRIE (SOI):
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Moving mirrors
Variable Optical Attenuator
Thermal actuator
moves the VOA
Si Mirror
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DRIE (SOI):
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• Because the small size of the manufactured
devices, MEMS processes have to be done in a
special controlled environment where the number
of dust particles or impurities can be controlled
by using special air filter unites.
• Cleanroom is a dedicated space where the level
of cleanness is variable from place to place
according to the process is being done.
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Cleanrooms:
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Laminar flow
cleanrooms
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Cleanrooms:
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MEMS market is a huge one and is growing day after day.
This market drives an even huge R&D activities in
universities/research centers.
The first MEMS devices measured such things as pressure in
engines and motion in cars.
MEMS are saving lives by inflating automobile air bags and
beating hearts.
MEMS are traveling through the human body to monitor blood
pressure.
MEMS are even getting smaller. We now have Nano electro
mechanical systems (NEMS), in lab more than in market.
The applications and growth for MEMS and NEMS are endless.
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1959 "There’s Plenty of Room at the Bottom" (R. Feynman)
1959 First silicon pressure sensor demonstrated (Kulite)
1967 Anisotropic deep silicon etching (H.A. Waggener et al.)
1968 Resonant Gate Transistor Patented (Surface Micromachining Process) (H. Nathanson, et.al.)
1970’s Bulk etched silicon wafers used as pressure sensors (Bulk Micromaching Process)
1979 HP micromachined ink-jet nozzle
1982 "Silicon as a Structural Material," K. Petersen
1982 LIGA process (KfK, Germany)
1982 Disposable blood pressure transducer (Honeywell)
1983 Integrated pressure sensor (Honeywell)
1986 The atomic force microscope is invented
1986 Silicon wafer bonding (M. Shimbo)
1988 Batch fabricated pressure sensors via wafer bonding (Nova Sensor)
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1988 Rotary electrostatic side drive motors (Fan, Tai, Muller)
1991 Polysilicon hinge (Pister, Judy, Burgett, Fearing)
1992 Grating light modulator (Solgaard, Sandejas, Bloom)
1992 Bulk micromachining (SCREAM process, Cornell)
1993 Digital mirror display (Texas Instruments)
1993 MCNC creates MUMPS foundry service
1993 First surface micromachined accelerometer in high volume
production (Analog Devices)
1994 Bosch process for Deep Reactive Ion Etching is patented
2000-present Inertial & navigation systems, Bio-MEMS, RF-MEMS,
Microphones, …etc
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