Mostafa Soliman, Ph.D. April 28th 2014mct.asu.edu.eg/uploads/1/4/0/8/14081679/mep382_l13... · 11...

1 Mostafa Soliman, Ph.D.

Mostafa Soliman, Ph.D.

April 28th 2014

History of MEMS

Naming Terminology

MEMS Applications

MEMS Devices

Market Shares and Revenues

MEMS Technologies


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]


On December 29th 1959, Dr. Richard Feynman,

from Caltech, presented a seminal talk, “There’s

Plenty of Room at the Bottom”.

In the 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


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.”


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.


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


In Europe, these systems are called “Microsystems” or

“MST”.

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.


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


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!


Variable Optical Attenuators


Scratch Drive Actuators (SDA)

SDAs push-pull a mirror


How about Middle East!!!!


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.


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


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:


Mechanical structures are fabricated by thin films deposited on the substrate

surface.

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Surface Micromachining:


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Surface Micromachining:


Mechanical structures are fabricated inside the substrate itself.

Method to make

cantilevers

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Bulk Micromachining (wet etching):


• 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):


Moving mirrors

Variable Optical Attenuator

Thermal actuator

moves the VOA

Si Mirror

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DRIE (SOI):


• 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:


Laminar flow

cleanrooms

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Cleanrooms:


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.

Mostafa Soliman, Ph.D. 37

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)


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


Mostafa Soliman, Ph.D. April 28th 2014mct.asu.edu.eg/uploads/1/4/0/8/14081679/mep382_l13... · 11...

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