2011 Introduction micro and nanotechnology

Jan Eite Bullema
version 2011
Introduction Micro-
and Nano Technolgy

Build Up of the Micro- and
Nanotechnology course
Introduction
History, markets, expectations
Materials for micro and nano
Processes and technologies
Micro and nano products
Converging technologies: MNBT
Medical applications
Packaging
Wrap-up / multiple choice test
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Reference Books
Reader:
Introduction Micro- and Nano Technology, J.E. Bullema
Further reading:
An Introduction to Micro Electro Mechanical Systems Engineering,
Nadim Maluf, ISBN 0-89006-581-0, 2004
Comprehensive Microsystems, Yogesh B.Gianchandani , 2007
Fundamentals of Micro System Packaging, Rao Tummala, 2001
Micro and Nanomanufacturing, Mark Jackson, 2010
Micro Systems Technology, Wolfgang Menz, 2001
Nano-Bio- Electronic, Photonic and MEMS Packaging, C.P. Wong 2010
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Introduction
Packaging
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Definition of Micro Systems Technology
MEMS/ Micro Systems Technology is simultaneously a toolbox, a
physical product, and a methodology, all in one:
• It is a portfolio of techniques and processes to design and create
miniature systems.
• It is a physical product often specialized and unique to a final
application one can seldom buy a generic MEMS / MST product at
the neighborhood electronics store.
• “MEMS / MST is a way of making things,” reports the Microsystems
Technology Office of the United States DARPA. These “things”
merge the functions of sensing and actuation with computation and
communication to locally control physical parameters at the
microscale, yet cause effects at much grander scales.
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Definition of Nanotechnology
The U.S. National Nanotechnology Initiative gives the following defining
features of nanotechnology:
1. Nanotechnology involves research and technology development at
the 1nm-to-100nm range.
2. Nanotechnology creates and uses structures that have novel
properties because of their small size.
3. Nanotechnology builds on the ability to control or manipulate at the
atomic scale.
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The Micro and Nano meter domain
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Hair Flake EggLouse
Diode
Solder-
line
Digital
Mirror
Transistor
IC line
(157 nm))
Pore
1 mm 0,1mm 0,01mm 1mu 0,1mu
Atom
(Co on Pt)
Back Finger Nail Bacteria DNA
PCB ICTelevision
Quantum
structure
Buckey
Ball
Semen
1m 0,1m 0,01mu 1nm 0,1nm0,01m
BIOLOGICAL Scale
TECHNOLOGICAL Scale

History Micro and Nano Technology: Feynman
The origin of the concept of micro and nano technology is the speech
‘There is plenty of room at the bottom’ given by Richard Feynman for
the American Society of Physics on December 29, 1959.
Feynman argued in his lecture that one would be able to do amazing
things by decreasing the size.
• Why cannot we write the entire 24 volumes of the Encyclopedia
Brittanica on the head of a pin?
• He also presented the "weird possibility" of "swallowing the doctor"
This concept involved building a tiny, swallowable surgical robot by
developing a set of one-quarter-scale manipulator hands slaved to
the operator's hands to build one-quarter scale machine tools
analogous to those found in any machine shop.
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History Micro and Nano Technology: Taniguchi
"‘Nano-technology’ mainly consists of the processing of separation,
consolidation, and deformation of materials by one atom or one
molecule."
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History Micro and Nano Technology: Drexler
Eric Drexler, a student of Feynman, wrote in 1986, Engines of Creation:
The Coming Era of Nanotechnology. Describing self-replicating nano-
assemblers building objects one atom at a time.
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History MNT: Binning and Rohrer
Binnig and Rohrer at IBM Zurich invented the scanning tunneling
microscope (STM) the first instrument to generate real-space images of
surfaces with atomic resolution. This discovery opened up the
important new field of nanotechnology and was recognized by the 1986
Nobel Prize in Physics. Subsequently, the atomic force microscope
(AFM) was developed. STM and AFM enabled not only the imaging of
individual atoms, but also the manipulation of a single atom.
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History Micro and Nano Technology: Smalley
Richard Smalley, is one of the scientists that is credited with
discovering buckyballs. Smalley and his co-workers, produced the
buckyballs in a device by vaporizing carbon with a laser and allowing
the carbon atoms to condense.
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History Micro and Nano Technology: Geim
Andre Geim and Konstatin Novoselov discovered graphene.
Graphene is a 2D mono layer of carbon, with remarkable physical
properties. Extreme mechanical strength, optical transparent, hermetic,
excellent electrical conduction. Graphene is already produced in
industrial quantities for display applications. As graphene is electrical
conductive and transparent (98% per carbon layer)
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Market Expectations: Perspective
2010 Estimates:
World Total Business ~ 55,000 Billion USD
Electronics Market ~ 1,000 Billion USD
GDP the Netherlands ~ 650 Billion USD
Semiconductor Market ~ 350 Billion USD
PhotoVoltaic Market ~ 40 Billion USD
Turnover Philips Electronics ~ 33 Billion USD
MEMS/MST Market ~ 7 Billion USD
Turnover ASML ~ 5,4 Billion USD
Nano Materials Composites ~ 0,5 Billion USD
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Market Expectations: MEMS / MST Market
(Source PCB May 2011)
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Sales M$ MEMS family Major Market
Texas Instruments
Hewlett Packard
Robert Bosch
STM Microelectronics
Panasonic
Seiko Epson
Canon
Denso
Freescale Semicond.
Avago Technologies
856
807
637
600
376
305
293
265
240
226
Electro Optic
Electro Fluidic
Electro Mech.
Electro Mech.
Electro Fluidic
Electro Fluidic
Electro Fluidic
Electro Mech.
Electro Mech.
Various
Projection / mobile
Ink jet printer cartridge
Airbag accelerometer
Airbag / Game acceler.
Airbag Accelerometer
Various
1. Ink jet cartridges, almost $2B
2. Airbag and gaming accelerometer, $1.8B
3. Projection, over $800M

Market Expectations: MEMS / MST Market
(Source Yole August 2011)
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Sales M$ MEMS family Major Market
Texas Instruments
Hewlett Packard
Robert Bosch
STM Microelectronics
Panasonic
Seiko Epson
Canon
Denso
Freescale Semicond.
Avago Technologies
856
807
637
600
376
305
293
265
240
226
Electro Optic
Electro Fluidic
Electro Mech.
Electro Mech.
Electro Fluidic
Electro Fluidic
Electro Fluidic
Electro Mech.
Electro Mech.
Various
Projection / mobile
Airbag accelerometer
Airbag / Game acceler.
Various
1. Ink jet cartridges, almost $2B
2. Airbag and gaming accelerometer, $1.8B
3. Projection, over $800M

MEMS and Sensors in Mobile Phones
(Source Yole August 2011
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Market Expectations: Medical MNT Devices
The total market for Medical Devices is estimated as follows:
Drugs and drug delivery 80 B USD
Blood Analyis 22 B USD
Heart Pacemakers & other implants 16 B USD
Endoscopes and MIS tools 5 B USD
Hearing Aids 4 B USD
DNA & Lab on a Chip 1,2 B USD
Micro and Nano Technology based Products accounts for an estimated
7 B USD, components account for 326 M USD.
www.tft-ltd.co.uk
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Market Expectations: Dutch MNT Companies
Company Product / Service
Aquamarijn Micro sieves
ASMI Various equipment
ASML Wafer stepper
Bronkhorst High Tech Flowsensors
C2V / Thermo fisher micro Gas chromatography
Cavendish Kinetics Non volatile memory
Cytocentrics Patch Clamping
Chemtrix Process intensification
EPCOS RF Switches
Fei Company Electron microscopy
Fluxxion Micro sieves
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Friesland Foods Application of micro fluidics in foods
Holst Institute System in Package development
IMS Micro Assembly Equipment
Levitor ALD Equipment
Lionix Development of technologies
Mapper Lithographic Equipment
Medspray Aerosol dispensing
Medtronic Maastricht Medical equipment , pacemakers
Microflown Acoustic pressure measurement
Mikronit Lab-on-a-chip
Miplazza Open innovation research facility
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Nanomi Functional Emulsions
NT MDT Scientific Equipment for Nanotechnology
NTS Ter Strake Equipment for Large Area Printing
NXP Oscillators, BAW filters
Oce Ink jet printing
Phoenix Software
Philips Electronics Various applications
Pie Medical Ultrasonic imaging
Sensata Pressure sensors
Sentron Solid State pH sensor
SolayTech ALD Equipment
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Solmates Pulsed Laser Deposition
Tempress Production Equipment, ovens
TNO Development of technology
Wetsus Sustainable water technology
XiO Photonics Optical switching
Xensor Integration Hall sensors
MinacNed is a Dutch interest group that brings companies together in this
field. Regular meetings are organized for interested parties. A yearly
conference Micro Nano Conference is organized, mostly in November of a
year.
http://www.minacned.nl/home.html
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Introduction
Packaging
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MEMS: Materials and Material Properties
Silicon
Silicon Oxide and Nitride
Thin metal films
Polymers
Other materials and substrates
Silicon Carbide, Gallium Arsenide, Shape Memory Alloys
Important properties and physical effects
Piezoresistivity, Piezoelectricity, Thermoelectricity, Hall Effect
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Silicon as a Mechanical Material
Kurt Petersen 1982
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Mechanical Properties of Crystalline Silicon
Silicon is hard and brittle.
Yield strength of 7 G Pa
(equivalent to 700 kg on 1 square millimetre)
Young modulus is dependent on the crystal orientation.
Average 160 GPa (for a (100) wafer E110 = 169 GPa E100 = 130
GPa)
Mechanical properties are influenced by dopants
(e.g. introduction of internal stress)
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Properties of Silicon
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Silicon is a Semiconductor
A semiconductor is a material with an electrical conductivity that is
intermediate between that of an insulator and a conductor.
A semiconductor behaves as an insulator at very low temperature, and
has an appreciable electrical conductivity at room temperature although
much lower conductivity than a conductor.
Bandgap
Diamont (C) 5,9 eV
Gallium Arsenide (GaAs) 1,42 eV
Silicon (Si) 1,14 eV
Germanium (Ge) 0,7 eV
Tin (Sn) 0,01 eV
Grafeen (C) 0 eV (halfmetal)
A bandgap below 3 eV is associated with a semiconductor
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Impurity Doping
Impurity doping. Introducing into a semiconductor material impurities of
foreign atoms (dopants) in relative dilute concentrations
Relative dilute is 10 13 - 10 20 foreign atoms / cm3
The impurities alter the electrical properties of the semiconductor. At
room temperature the carrier concentration is nearly equal to the
dopant concentration.
If the dopant is n-type (Arsenic, Phosphorus) there is an excess of
electrons. For p-type there is an excess of holes (dopant Boron)
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Electron Speeds in Various Semiconductors
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Resistivity of Doped Silicon
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Availability of Silicon
Three forms of Silicon are relevant for MEMS
- Crystalline
- Poly Crystalline / poly silicon
- Amorphous
Crystalline silicon is available in circulair wafers
100 mm (4''), 150 mm (6''), 200 mm (8'') and 300 mm (12")
450 mm is expected in the near future
100 mm wafer has a thickness of 525 micron
150 mm wafer has a thickness of 650 micron
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Miller Indices
Orientations in planes are often described in so-called Miller indices
[100] x,y,z vector orientation
<100> 6 directions +x,-x,+y,-y,+z,-y
(111) a plane  on the [111] vector
{111} describes all 8 equivalent (111) planes
Planes and there orientations
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Anisotropic Properties of Silicon
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(a) face view (100); (b) edge view (110); (c) vertex view (111).
Three crystallographic planes and their Miller indexes
Four of the eight equivalent (111) planes in the {111} family.

Anisotropic Properties of Silicon
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Silicon Wafers
Material manufacturers cut thin circular
wafers from silicon boules along specific
crystal planes. The cut plane - the top
surface of the wafer - is known as the
orientation cut, and is encoded on the
wafer itself in the form of a primary and
a secondary flat located on the side of
the wafer.
Commercially available wafers are predominantly of {100} orientation,
which is the preferred orientation cut for CMOS technology. In addition
to the cut impurity doping (p or n) and electrical resistivity
(in Ohm m) are specified by the supplier
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KOH Etch of Silicon
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The etch rate of silicon
with KOH depends on:
- the concentration
of the KOH solution
- the temperature
- the Si crystal orientation

Poly Silicon
Usually deposited as layer or thin film (5 micron) on a surface.
It is used as:
- micromechanical structure (e.g in accelerometer of Analog Devices)
- electrical interconnect
- thermocouples
- p-n junction
Mature technology to create planar micro mechanical structures
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Poly Silicon an Amorphous Silicon
The mechanical properties vary with deposition conditions, but in
general they are the same as for single-crystal silicon
Normally both suffer from intrinsic stress (hundreds of M Pa) which
requires annealing at elevated temperatures (> 900 °C)
Beams of poly silicon or amorphous silicon that have not been
subjected to a careful stress annealing step can curl up under the effect
of intrinsic stress
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Material Properties of Crystaline Silicon
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Interesting Properties of Silicon
Silicon conducts heat circa 100 times better than glass.
Silicon does not function as a Laser (as GaAs for instance does), but
can interact with light and function as a detector.
Silicon is transparent above wavelengths of 1,1 micron.
Silicon reflects light below circa 400 nm (Bleu) at 60 %
Above 500 degrees °C Silicon becomes soft,
plastic deformation sets in.
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Interesting Properties of Silicon
Silicon is resistant to most chemicals (e.g freon or brake fluids)
Interaction with gasses, chemicals, biological fluids, and enzymes
remains subject of studies
In medicine and biology there are on-going studies to evaluate silicon
for chronic medical implants. Preliminary medical evidence indicates
that silicon is benign in the body and does not release toxic substances
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Reflectivity of Silicon
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Selected Properties of Silicon
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Properties of Silicon Oxide
SiO2 Softens above 700 degrees Celsius.
Important that it is electrically insulating, unlike germanium oxide which
oxide is also soluble in water. Gallium Arsenide which oxide can not be
grown appreciably.
Various forms of SiO2 and SiOx, silicate glass are used in
micromachining due to their excellent electrical and thermal insulation
properties.
Also often used as sacrificial layer in surface micromachining
processes, because they can be preferentially etched with hydrofluoric
acid (HF) which is selective to Silicon
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Etching of SiO2 in KOH
KOH etching of silicon dioxide is observable. The etch rates are
considerably slower (1-2 orders of magnitude) than that of silicon but
should be considered when deep etching is being done.
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Silicon On Insulator (SOI)
SOI wafer, where the top single crystalline silicon layer (device layer)
on an oxide film(buried oxide) is fabricated on a silicon wafer (handle
wafer), is widely used in microsystems as well as in semiconductor
devices.
In microsystems, the most attractive feature is that the single crystalline
silicon can be used as structural materials. In surface micromachined
devices.
Relatively thick SOI wafers, whose device layer thickness is more than
a few microns, are widely used in accelerometers, vibrating
gyroscopes, and micromirrors.
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Properties of Silicon Nitride
Si3N4, SiyNx is also widely used as an insulation thin film, it has also
excellent properties as a barrier against mobile ion diffusion. In
particular sodium and potassium ions as found in biological
environments
Its Young modulus is higher than that of silicon and can be controlled
by the specifics of the deposition process
Silicon nitride is an effective masking material in many alkaline etching
solution
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Etching of Silicon Nitride in KOH
KOH etching of silicon nitride was not observed in the study.
Therefore, the silicon nitride etch rate is under 1 nanometer per hour if
it etches at all. If silicon nitride is being used as a mask for silicon
etching, potential etching of the silicon nitride need not be taken into
consideration.
J. Electrochem. Soc. Vol 137, 11, Nov 1990, 3612-3632.
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Thin Metal Films
Metal  .cm) Typical Areas of Application
Ag 1.58 Electrochemistry
Al 2.7 Electrical Inteconections
Optical reflection visible & infrared
Au 2.4 High Temp. Electrical Interconnect
Optical reflection infrared
Electrochemistry
Cr 12.9 Intermdiate Adhesion Layer
Cu 1.7 Low Resisitivity Interconnects
ITO 300 - 3000 Transparent Conductive Layer
W 5.5 High Temperature Interconnects
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Thin Metal Films
Pd 10.8 Electrochemistry
Solder Wetting layer
Permalloy - Magnetic Transducing
Pt 10,6 Electrochemistry
Electrodes for Bio-potential
SiCr 2000 Thin Laser Trimmed Resistor
SnO2 5000 Chemo-resistance Gas Sensors
TaN 300 - 500 Negative TCR
TiNi 80 Shape Memory Alloy
TiW 75 - 200 Intermediate Adhesion Layer
Near Zero TCR
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Thin Metal Films
Ir 5.1 Electrochemistry
Micro Electrodes Bio-potential
Ni 6.8 Magnetic Transducing
NiCr 200 - 500 Laser-trimmed resistor
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Polymers (SU8)
In silicon micromaching polymers are often deposited in thin layers
from a few nanometers to hundreds of microns
Special photoresists (e.g. SU-8) can be brought up to 1000 micron
thick.
Hardening under UV light produces rigid structures.
Spin on organic polymers are general limited in their application
due to shrinkage due to solvent evaporation
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SU8
SU-8 is a negative-tone photoresist chemically amplified resist
system with excellent sensitivity and high aspect ratios. The
primary applications are micro fabricated mechanical structures
(MEMS) and other microsystems.
Examples are sensors, microfluidic components, electronic coils, inkjet
print head nozzles, MR and GMR heads, multichip modules, actuators,
LCD spacers and moulds for plastic, stamps for hot embossing
and electroplating
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PolyDiMethylSiloxane (PDMS)
Polydimethylsiloxane is one of the most widely used polymers in
MEMS, especially in microfluidic and bioMEMS. It belongs to a class of
polymers called silicones, which are synthetic polymers containing a
Si–O backbone.
Silicones are different from most other polymers in that the backbone
chain of atoms is silicon rather than carbon. Silicones are very
compliant and have been used as the deformable membrane in valves,
as well as being a common die-attach material in packaging.
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Glass, Quartz
Glass and silicon fit together well.
Close match of CTE and suitable for anodic bonding
Quartz has as an extra advantage that it shows piezo electrical
behaviour
Machining can be done by:
- HF etching,
- ultrasonic machining or
- powder blasting
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Silicon Carbide and Diamond
Both materials offer extraordinary hardness and resistance to harsh
environments. Micro machining of both materials is still in its infancy
Both materials demonstrate piezoresistive properties
Silicon carbide is sometimes used as a coating material for harsh
environments
Bandgap of SiC is 3,03 eV
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III-V Semiconductors
Very well suitable for manufacture of lasers and other optical devices
Use in RF devices and high speed electronics. GaN is becoming more
important in LED applications and power electronic applications.
• GaAs
• InP
• AlGaAs
• GaN
• InGaN
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Smart Memory Alloys
Invented in 1951 AuCd alloy
The material remembers its original form after being strained and
deformed. Alloys:
• TiNi
• Cu Al Ni
• FeNi
• Fe Pt
Practical limitation lies in the transition temperature.
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Shape Memory Alloys
A shape memory alloy (SMA) (also known as memory metal or smart
wire) is a metal that remembers its geometry. After it is deformed, it
regains its original geometry by itself during heating (one-way effect)
or, at higher ambient temperatures, simply during unloading
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Important Physical Effects
Piezoresistivity
Piezo electricity
Thermoelectricity
Hall-Effect
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Strain Gauge
A strain gauge is a device used
to measure deformation (strain)
of an object. The most common
type of strain gage consists of a
flexible backing which supports a
metallic foil pattern etched onto
the backing.
As the object is deformed, the
foil pattern is deformed, causing
its electrical resistance to
change. This resistance change,
usually measured using a
Wheatstone bridge circuit
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Piezo electricity
Certain classes of crystals exhibit the peculiar property of producing
an electrical field when subjected to an external force
They are attractive to MEMS because they can be used as well as
sensors as well as actuators and they can be deposited as thin film
on silicon
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Piezo electric coefficients
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Piezo electric effect
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Thermo electricity
The Seebeck effect is the conversion of heat differences directly into
electricity.
The Peltier effect is the reverse of the Seebeck effect; a creation of a
heat difference from an electric voltage
Thomson effect, describes the heating or cooling of a current-carrying
conductor with a temperature gradient. Any current-carrying conductor,
with a temperature difference between two points, will either absorb or
emit heat, depending on the material.
Seebeck is most used, in thermocouples to measure temperature
differences
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Seebeck coefficients relative to Pt
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Hall Effect
(www.sensedu.com)
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Some Sensing methods
Piezo resistive
Capacitive
Electromagnetic
Thermoelectric
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Capacitive sensing
Capacitive sensing relies on an external physical
parameter changing spacing or dielectric constant
Advantage of capacitate measurement are
(1) that it requires little energy
(2) it is relative temperature insensitive
(3) it gives the possibility to closed loop feedback
Disadvantages are
(1) Capacitive sensing requires large electronics
Measurements can be done down to pF level
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Piezo Electric actuation
Piezo Electric actuation can provide relative large forces
Thick Piezo electric films are used up to a few Newton's with a few
hundred Volts applied
Thin films ( < 5 micron) only a few milli Newton's
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Actuators
A complete paradigm change is necessary when thinking of actuating at a
micro scale. A four stroke engine is not scalable
Electrostatic Actuation
Piezo Electric Actuation
Thermal Actuation
Magnetic Actuation
Shape Memory alloys
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Thermal Actuation
Thermal actuation consumes more power than electrostatic or piezo electric
actuation. But it can provide, despite its gross inefficiencies, actuation to
hundreds of milli Newton's or higher
- Traditional bimetal
- Thermo pneumatic
- Suspended beam heating
Notice: First two methods are ambient temperature dependent
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Introduction
Packaging
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MEMS Processes
Basic Process Tools:
Epitaxy, Oxidation, Sputter deposition, Evaporation,
Chemical Vapor Deposition
Spin-on methods, Lithography, Etching
Advanced Process Tools:
Anodic bonding, silicon fusion bonding, grinding polishing and
Electrochemical polishing, Sol-gel deposition methods
Bosch Process: DRIE
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MEMS Processes
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Epitaxy
General method to grow a crystaline layer of silicon on a
silicon wafer, with use of dopants specific properties can be
given {AsH3, PH3 (n-type), B2H6 (p-type)}
- layer thickness 1- 20 micron
- same crystaline orientation as wafer
- much used in CMOS (efficient p-n junctions)
- Temperature (> 800 °C) with SiH4, SiH2Cl2, SiCl4
- grow speeds 0,2 - 1,5 micron per minute
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Epitaxy: Silicon on Safire
So called hetero epitaxy, were two different materials are grown.
In this case Silicon on Safire (Al2O3)
Process is called SOS
Due to crystalline structure the layers of silicon on safire have to
stay thin (due to increasing defects the electrical properties of
silicon degrade)
SOS is used when optical or electrical properties require this
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Oxidation
Silicon dioxide is obtained by oxidizing silicon with dry oxygen or
steam at 850 - 1100 °C
Very well known process. Oxidation introduces compression
stress in the material because SiO2 needs more volume than
Silicon
The compression stress can be several hundreds MPa
Stress in a layer can lead to warping and curling
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Sputtering
In sputtering a target material is bombarded with inert ions (e.g. Argon
or Helium) Some material of the target is released and deposited on a
wafer
Three basic forms
- DC glow discharge
- Planar RF
- Cylindrical Magnetron or S-gun
Large range of materials: Al, Ti, Cr, Pt, Pa, Si, glass, Piezomaterial.
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Sputtering
Schematic illustration of a sputtering apparatus.
In the sputtering process, positively charged
argon ions strike the target biased negatively
and remove target atoms. These sputtered
atoms condense on the substrate to form a thin
film.
Sputtering parameters such as substrate
temperature, sputter gas pressure, target-to-
substrate distance, and target power play an
important role in the structure and composition
of deposited films.
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Sputtering
Depending on target size a good step covering can be obtained.
The film has a fine granular structure
Depending on the sputtering pressure the stress in the layer goes from
tensile (low pressures 0,1 - 1.0 Pa) to compressive (1 - 10 Pa) Good
pressure control is necessary for controlling stress
Advantage of sputtering is the relative low temperature (150 C)
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Evaporation
Local heating of target material with subsequent condensation on a
substrate. Nearly any material is suitable: Al, Si, Ti, Mo, glass, Al2O3,
etc
Inclusive refractory materials: W, Au, Cr, Pd, Pt as long as the vapor
pressure is higher than the background pressure
Important is that the carrier (mostly W) does not evaporate
Stress in the layer can become very large (depending on the
temperature) in W up to 500 MPa
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Thermal Evaporation
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Chemical Vapour Deposition
Chemical Vapour Deposition is mostly a process at elevated
temperatures (> 300 °C)
Materials that can be deposited are:
- silicon,
- poly silicon
- amorf silicon
- SiO2
- Si3N4
- Cu and low r material
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Common CVD Deposition Chemistries

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Chemical Vapour Deposition
There two important forms of CVD:
- Low pressure Chemical Vapour Deposition (LPCVD)
- Plasma Enhanced Chemical Vapour Deposition (PECVD)
LPCVD temperatures > 800 °C
PECVD temperatures ~ 300 °C
Many layer properties can be controlled with deposition parameters
(pressure, temperature, gas flow, dopants, power and plasma
excitation)
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Example PE- CVD Equipment
The Plasma Enhanced Chemical Vapor
Deposition (PECVD) machine is used to
deposit thin dielectric films. It combines up
to four gases at pressures between
0.1 and 1 Torr and uses an RF source
of up to 200 Watts to ionize the resultant
gas mixture, causing film deposition on
a heated substrate.
Films deposited with the system include:
SiO2, SiOxNy, and Si3N4.
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Polysilicon with CVD
Polysilicon deposition on a wafer can be done from tens of nm to
several microns thickness on a silicon wafer
Easy to apply by pyrolysis of Silane (SiH4) with LPCVD at 550 - 750
°C. PECVD is also possible.
Depending on process conditions amorphous or crystalline silicon is
obtained.
Good step covering
Stress can be reduced by annealing > 900 °C
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Silicon dioxide with CVD
Silane and oxygen in a CVD reactor result in on SiO2 layer
Boron and or phosphorus can be build in to obtain specific properties.
E.g. Low Temperature Oxide (LTO) which can be used to obtain an
excellent step coverage of the SiO2 layer by heating to 1000 °C
Silicon oxide also can be obtained by pyrolysis of [Si(OC2H5)4]
TEOS (tetra ethoxy silane) in LPCVD at 650 - 700 °C
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Silicon Nitride with CVD
Silicon nitride is good for passivation and an excellent barrier for water
and sodium ions. For MEMS it is an excellent mask for etching with
KOH
Stoichiometric Si3N4 is obtained by atmospheric CVD of SiH4 and NH3
or SiCl2H2 and NH3 at 700 - 900 °C
H2 is absorbed in the layer which lead too large tensile stresses
(e.g. 1000 MPa)
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Spin on methods
With spin on methods layers of dielectric insulators and organic
materials can be applied
A table spins with typical 500 - 5000 rpm
Thicknesses are 0,5 - 20 micron
For SU-8 epoxy it can be 1 up to 1000 micron
Glasses also can be applied
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Lithography
Lithography has three essential steps:
- application of photoresist with a photosensitive emulsion layer
- optical exposure to print an image of the mask into the resist
- immersion in an aqueous development solution to dissolve exposed
resist and render visible the latent image
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Lithography
There are three main forms of lithography
- Contact
- Proximity
- Projection
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Lithography
Resolution:
- contact 1 - 2 micron
- proximity 5 micron (Fresnel limitation)
- projection (better than 1 micron)
Depth of Focus is sometimes limiting for thicker structures
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Comparison Wet and Dry Etching

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Example Lithography Equipment
The Canon Parallel Light Mask Aligner
is a machine used in the process of
lithography. The shown machine allows
for the use of 4-5 inch photomasks
and can handle 2-5 inch wafers.
Both the mask and wafer can be brought
into sharp focus, facilitating the proper
alignment of mask and wafer for
maximum exposure accuracy.
.The maximum print diameter is 5 inches, which is a relatively large exposure area.
As such, the number of devices per wafer and throughput is increased. This Canon
Aligner is also equipped with an auto feeder, allowing hands-off loading and
unloading of the wafer
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Double Sided Lithography
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Thick resist
With multiple spin on process a thick resist layer can be obtained.
Due to height differences (topological height variations) some
processes become very difficult.
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Etching
Etching processes in MEMS are derived from traditional etch processes
for semiconductor processes.
‘Underpinning is in science, much remains an art’
The objective is to selectively remove material using imaged
photoresist as a masking template.

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Etchants of Silicon

102
Isotropic and Anisotropic Etching

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Anisotropic Etching

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Anisotropic Etching: Suspended beam

105
Etchants of Thin Metal Films and Insulators

Deep Reactive Ion Etching (Bosch Process)

109
Isotropic wet Etching
Common wet etchant is HNA also known as poly etch
H = Hydrofluoric Acid (HF)
N = Nitric Acid (HNO3)
A = Acetic Acid (CH3COOH)
Nitric acid oxidizes silicon which is removed by HF
Etch depth and surface condition are mostly difficult to control (Etch
rate up to 20 micron)

Anisotropic wet etching
Anisotropic wet etchants include the hydroxides of alkali metals (KOH,
NaOH, CsOH, etc), simple and quaternary ammonium hydroxides
(NH4OH, (CH3)4NOH)
Potassium hydroxide is the most common
KOH etches the {111} planes 100 times faster than the {100} planes.
This feature is routinely used to make V shaped grooves that are
precisely delineated by the {111} crystallographic planes

Anodic bonding
Bonding of silicon and sodium containing glass (Pyrex 7740 and 7070
or Schott 8330 and 8329) It is fundamental to manufacture of a wide
variety of sensors, including pressure sensors, because it provides a
rigid support in the form of a glass substrate rather than the fragile
silicon
bonding at 200 - 500 °C in vacuum, air or inert
application of a voltage 500 - 1500 V across the two substrates

Anodic bonding

Silicon fusion bonding
Silicon fusion bonding, also known as direct wafer bonding is a process
capable of securely joining two silicon substrates
The bonding mechanism is not well understood but it is widely believed
that it occurs at a molecular level.
Formation of OH groups on the surface and cleanliness are important.
A temperature anneal at 800 - 1000 °C promotes and strengthen the
bond reaction

LIGA (LIthography, Galvanie, Abformung)

SU-8 Process

SU-8 Epoxy
SU-8 Epoxy Structures
Examples of SU-8 epoxy structures that are available as foundry
processes. Structure heights from 1 micron to 1 millimeter are possible
and side-wall angle can also be controlled for various geometries.

Process Flow

Introduction
Packaging
118Jan Eite Bullema

MEMS Products
Pressure Sensor
Accelerometer
Mass Flow Sensors
Digital Micro mirror Device
Angular Rate Sensors
Fluid Nozzles, inkjet print nozzles, micro filtration
Micro machined valves

Relative Merits different sensing principles

Pressure sensor

Fabrication steps for a piezoresistive gauge
Pressure sensor

Pressure sensor

Pressure sensor
Fabrication process of a SOI high-temperature pressure sensor.

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Pressure sensor

Pressure sensor
The machined silicon-structure is protected in an elektronics package

Nano Probe
Beams of the Silicon part
are 20 – 30 m thick, the
function of the nano probe
requires thin beams
For assembly thin beams
are challenging

Flow Sensor
Gas flow cools the upstream heater and heats the downstream heater.
Temperature-sensitive resistors are used to measure the temperature of each
heater and consequently infer the flow rate. The etched pit underneath the
heater provides exceptional thermal isolation to the silicon support frame.

Accelerometer
Acceleration
(1) Front and side airbag crash sensing (2) Electrically controlled car
suspension. (3) Safety belt pretensioning . (3) Vehicle and traction control
systems. (4) Inertial measurement, (5) object positioning, and navigation
(6) Human activity for pacemaker control
Vibration
(1) Engine management (2) Condition-based maintenance of engines
and machinery (3) Security device (4) Shock and impact monitoring
(5) Monitoring of seismic activity
Angles of inclination
(1) Inclinometers and tilt sensing (2) Vehicle stability and roll (3) Computer
peripherals (e.g., joystick,head mounted displays … ) (4) Handwriting recognition
(e.g., SmartQuill from British Telecom) (5) Bridges, ramps, and construction

Acclerometer: Principle

Differences in G measurements
Airbag 50 G Bandwidth 1 k Hz
Motor sensor: 1 G resolution 100 micro G Bandwidth > 10 kHz
Hart sensor: 2 G Bandwidth 50 Hz
ultra low power consumption
Military sensor: 1000 G
Drop test: 10 000 G

Accelerometer
Illustration of a piezoresistive accelerometer from Endevco Corporation fabricated
using anisotropic etching in {110} wafers. The middle core contains the inertial
mass suspended from a hinge. Two piezoresistive sense elements measure the
deflection of the mass. The axis of sensitivity is in the plane of the middle core.

Bulk micro machined PZR sensor
Proof mass typical 100 micro grams
PZR (Boron doped Silicon) 0,6 micro thick 3,4 micron broad
Signal in Wheatstone bridge typical 1 G / 25 mV over 10 V
Measurement until 6000 G
Shock proof 10000 G
Bandwidth 28 k Hz

Accelerometer
Capacitive bulk-micromachined accelerometer. The inertial mass in the middle
wafer forms the movable electrode of a variable differential capacitive circuit.
Adapted from the accelerometer product catalog

Accelerometer
Process steps to fabricate the middle wafer containing the hinge and the
inertial mass of a capacitive bulk-micromachined accelerometer

Bulk Micro Machined Capacitive Sensor
Capicitance translated to + - 2,5 V
Measurement 1.5 to 50 G
Shock proof 20000 G
Bandwidth 400 Hz

Accelerometer
Basic structure of the ADXL family of surface- micromachined accelerometers.
A comb-like structure suspended from springs forms the inertial mass.
Displacements of the mass are measured capacitively with respect to two
sets of stationary finger-like electrodes.

Surface Micro Machined Capacitive Sensor
Proof mass typical 0.3 to 1 micro grams
Total capacitance 100 f F (f = femto = 10-15)
Measurement 100 aF (a = atto = 10-18)
100 aF equals circa 625 electrons
no parasitic currents are allowed all signal processing on the sensor
Measurement typical airbag 1 - 50 G
Price current below 3 USD per product (Bosch and Analog Devices)

Accelerometer
Photograph of a deep-reactive-ion-etched (DRIE) accelerometer using
60-mm-thick comb structures.

DRIE Capacitive Sensor
Total capicitance 3 pF (p = pico = 10-12)
Thermal Noise: 10 G /  Hz
Compared to surface micro machined sensor
Thermal Noise: 500 G /  Hz

Accelerometers
Commercial accelerometers only cost a few Euros

Angular-rate sensor
A conventional mechanical gyroscope and the three rotational degrees of
freedom it can measure.

Angular-rate sensor
The Coriolis acceleration on an object moving with a velocity vector v on the
surface of Earth from either pole towards the equator. The Coriolis acceleration
deflects the object in a counterclockwise manner in the northern hemisphere
and a clockwise direction in the southern hemisphere. The vector  represents
the rotation of the planet.

Angular-rate sensor
Tuning fork structure for angular-rate sensing. The Coriolis effect transfers
energy from a primary, flexural mode to a secondary, torsional mode.

Angular-rate sensor
The corresponding standing wave pattern

Angular-rate sensor
Angular-rate sensor. The basic structure consists of a ring shell suspended
from an anchor by support flexures. A total of 32 electrodes (only a few are
shown) distributed around the entire perimeter of the ring excite a primary mode
of resonance using electrostatic actuation. A second set of distributed
electrodes capacitively sense the vibration modes. The angular shift of the
standing wave pattern is a measure of the angular velocity.

Angular-rate sensor
VSG angular-rate sensor from British Aerospace Systems and Equipment, and
corresponding fabrication process. The device uses a vibratory ring shell design,
similar to the Delco sensor. Eight current loops in a magnetic field, B, provide the
excitation and sense functions. For simplicity, only one of the current loops is
shown.

Angular-rate sensor
Angular-rate sensor from Daimler Benz. The structure is a strict implementation
of a tuning fork in silicon. A piezoelectric actuator excites the fork into resonance.
The Coriolis force results in torsional shear stress in the stem which is measured
by a piezoresistive sense element.

Angular-rate sensor
The main fabrication steps for the Daimler Benz micromachined angular-rate
sensor.

Carbon monoxide sensor
Carbon monoxide sensor, its equivalent circuit model, and the final packaged
part. The surface resistance of tin-oxide changes in response to carbon
monoxide. A polysilicon heater maintains the sensor at a temperature between
100 and 450º C in order to reduce the adverse effects of humidity.

DMD™
Single DMD™ pixel in its resting and actuated states. The basic structure
consists of a bottom aluminum layer containing electrodes, a middle aluminum
layer containing a yoke suspended by two torsional hinges, and a top reflective
aluminum mirror. An applied electrostatic voltage on a bias-electrode deflects
the yoke and the mirror towards that electrode. A pixel is 17 m on a side.

DMD™
Optical beam-steering using the switching of micromirrors. Off-axis illumination
reflects into the pupil of the projection lens only when the micromirror is tilted in
its +10º-state, giving the pixel a bright appearance. In the other two states, the
pixel appears dark

DMD™

Grating Light Valve
Operating principle of a single pixel in the grating light valve. Electrostatic pull-
down of alternate ribbons changes the optical properties of the surface from
reflective to diffractive.

Passive structures
Nozzles are the most simple passive structure
Patents for IBM In the 1970s for silicon nozzles for ink jet application
Patents for Ford in the 1980s for motor fuel injection applications
Nowadays these patents are expired. Many new research in the field of
medical inhalers, atomizers, fluid spray systems

Passive structure

Passive structures

Inkjet
Cross-sectional illustration of a thermal inkjet head and the ink firing sequence.

Various actuation methods

Micro Valves

Development of Microfluidic Interconnection
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Areas of Expertise 172

Introduction
Packaging
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Wireless EEG Measurement
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Introduction
Packaging
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Medical Applications of Micro and Nano
Technology
Jan Eite Bullema
‘It would be interesting in surgery
if you could swallow the surgeon’
Richard P. Feynman
177

Pacemaker
The pacemaker is one of the oldest examples of a MST product

Pacemaker Historic Developments (1950)

Pacemaker Historic Developments (2000s)

Pacemaker ( Integration of Functions)
Integration of Functions
In the pacemaker by:
- MEMS Accelerometer
- Digital control
- Remote diagnostics
- use of MEMS switches

jan_eite.bullema@tno.nl
Medical Applications of Micro and
Nano Technology
Pacemaker Decreasing Dimensions
MEDTRONIC, is using micro electronics
and chip manufacturing to shrink pacemakers
– implanted devices that regulate the hearts
rhythm. Whereas current pacemakers are
the size of a silver dollar. Medtronics new
device would be smaller than a tic-tac.
At that size the pacemaker could be inserted
through a catheter rather than invasive surgery
http://www.technologyreview.com/biomedicine/32436

Implantable wireless pressure sensor
CardioMEMs’ device measures blood pressure in people who have an
abdominal aortic aneurysm. Doctors can treat the bulging artery with a
stent graft, stents can fail, aneurysm patients require lifetime monitoring

Nano Technology
Implantable wireless pressure sensor
184

Nano Technolo
Stents
185

Hearing Aid
Trend is that products become
smaller
and
smarter
This is enabled by developments
In micro electronics and in micro
systems technology

Type Typical cost
Euro per unit
Behind the ear 200 - 300
In the ear 500 - 700
In the canal 700 - 1000
Completely
in the canal 1400 - 2000
Cochlear Implants 35000 - 50000
Hearing Aids & Cochlear implants

Hearing Aids
Source: Phonak

Cochlear Implants
1985 1991 1997 1999 2000 2004

Nano Technology
Flexible Solar Retinal Implants
Age related Macular
Degeneration (AMD)
Affects about 1,5 Million
people per year in the US
and is the most prevalent
cause for blindness in the US

Nano Technology
Flexible Solar Retinal Implants

Retinal Implant
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Nano Technology
Eye pressure measurement
in glaucoma patients
In the eye pressure sensor
- a pressure sensor
- a low-power microprocessor
- a solar cell
- a wireless radio
- memory
- and a thin film battery.
http://techknowbits.com

Endoscope
Source: PENTAX FG-32UA

Smart pill
This smart-pill (M2A capsule) contains
a number of the functions that a
microsystem can have:
- The pill can observe with a camera
- The pill has a processor to process
signals to information
-The pill has coil to transmit information
- The pill has a battery for energy
supply purposes

Properties of the smart pill
The capsule is 11mm x 26mm (<4 grams)
Field of view is 140 degrees.
Detection of objects at a minimum size
less than 0.1 mm
In a normal (8 hr) procedure the
generates approximately 57,000 images,
at a rate of two frames / second.

Capsule Endoscopy Image
Eosinophilic Enteritis
visualizing folds
of the cecum
Cecum Nematodes
Pinworm in
healthy volunteer
Note thickened...
Kaposi’s Sarcoma
cutaneous Kaposi’s
Normal ColonHemorrhagic
60 year old woman Normal vessels

Billicheck improves comfort
Not a heel puncture but an optical measurement
The analysis is done with a plastic grating
The grating is made with LIGA technology

Optical Diagnosis with MST components
Source: Micro Parts
Color Check of Teeth Bili Check for Jaundice

Drug Delivery Pill: iPill by Philips
Philips has developed
a drug delivery pill
(2.6 x 1.1 Ø cm)
30% is drug container
It measures pH and
temperature and can
deliver drugs on site
IMAPS iPill for controlled drug delivery – Frits Dijksman, November 20-th 3-rd, 2008

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Length small intestines 4-6 m
Drift velocity (due to peristalsis) in small
intestines 1 m/h
Residence time in small intestines 4-5
hrs
Length large intestines 1-1.5 m
Throughput time1-5 days
202

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• Crohn’s Disease and Ulcerative
Colitis
• Chronic autoimmune disease of
• unknown etiology
• Prevalence: ~1.4M in U.S., similar in
Europe
• High patient burden and cost to
society
• Significant unmet needs in diagnosis,
treatments, and disease management
204

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• Dimensions length 26 mm, diameter 11 mm
• Weight 3.2 gr (specific mass 1450 kg/m3)
• Medication content 300 micro liter
• Minimum dispensed volume 1 micro liter
• Once per 20 seconds the status on temperature, pH, medication
content, battery will be transmitted to the outside of the body
• Reach RF link 0.3 m in the body
205

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Drug Delivery Pill
Diagnostic Therapeutic
Non-invasive Non Invasive
Miniaturized Miniaturized
Patient Comfort Intelligent Device
Ease of Use Individual Therapy
High Data Content Disease Management
Faster Health Monitoring
Cheaper Compliance Monitoring
206

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Bullema207
Permanent medication dosing
The artificial pancreas gives the diabetic patient a continuous
and correct dosing of insulin

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Insulin Dispenser
Debiotech’s Insulin Nanopump
Each pump actuation injects only 200
nanoliters of drug,and reproducibility is
better than 2%, bringing it very close
to physiological delivery of insulin.

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Aerosol dispenser
By the micro holes an aerosol can be dispensed with
droplets of a very well defined droplet diameter
(droplets of circa 1 micron diameter)

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Aerosol dispenser
210

Catheters for key-hole surgery
A surgical doctor inspects a pressure sensor before he
Starts measuring the pressure in the heart of the patient

Catheters for brain measurements
Length: 340 mm
Diameter: 0,6 mm
Electrodes: 31 + 1
Array length: ca. 6 mm

Neuroprobes for brain probing
2mm shank length: 112 electrodes
8 mm shank length: 512 electrodes

Full 3D array for brain probing

Microfluidics: Market
World Market Microfluidics (MST News Feb 2008)
2004 2009 (prognosis)
Volume 630 M USD 1500 M USD
Microfluidic Chips 65% 67%
Pressure Sensors 23% 13%
Drug Delivery 1% 13%
IR Sensors 5% 3%
Micro Spectrometers 3% 2%
Other 2% 3%

Lab-on-a-chip (micro array)
By capillary action the sample is pulled to the reactive spots
Small sample volume + large number of analysis simultaneously

Microfluidics: Overview
One important manner in which microfluidics differs from micro
electronics. Is that the fundamental physics changes more rapidly as
the size scale is decreased
Micro fluidics quickly reach length scales were fundamental fluid
physics change dramatically.
E.g.
Reynolds (Re) = inertial / viscous = . U0 .L0 / 
Péclet (Pe) = convection / diffusion = U0 . L0 / D
Capillary (Ca) = viscous / interfacial =  . U0 / 

Micro fluidics: Reynolds (viscous / interfacial)
Reynolds (Re) = inertial / viscous = . U0 .L0 / 
Flow in micro channels has typically Re 10 -6 to 10
{ water (1 mPa.s, diameter (L0) 1 – 100 mm, flow (U0) 1m/s to 1cm/s }
Flow in micro channels is always laminair as
viscous forces >> inertial forces
Spermatozoa ~ 1×10 −2
Blood flow in brain ~ 1×102
Blood flow in aorta ~ 1×103
Onset of turbulent flow ~ 2.3×103
Person swimming ~ 4×106
Aircraft ~ 1×107
Blue whale ~ 3×108
A large ship (RMS Queen Elizabeth 2) ~ 5×109

Microchannels in Plastics
Micro channels are used more and more in ‘Lab on a Chip’ products
The example is a capillary with a width of 100 micron

Lab-on-a-Disk
The Gyros device uses a passive valve principle. Some parts of the
micro-channels have hydrophobic properties. These will act as a closed
valve, fluid can not pass due to the hydrophobic surface. As the device
is rotated, centrifugal forces will overcome the hydrophobic forces and
pass the hydrophobic valve region.
Gyros: Lab-on-a-Disk

Legionella detection

Smart Diagnostics for Healthcare
Sample
Biopsy
Filtering /
Concentrating
Lysis /
Extract DNA
Seperating
DNA / Rest
PCR
Washing /
Filtering
DNA
detection
Sample preparation and analysis on a 1’ x 3’ (25 x 75 mm) lab-on-a-chip
Washing
1 2 3 4
4 65 7

Genome Size
FERN 160,000,000,000
LUNGFISH 139,000,000,000
SALAMANDER 81,300,000,000
NEWT 20,600,000,000
ONION 18,000,000,000
GORILLA 3,523,200,000
MOUSE 3,454,200,000
HUMAN 3,400,000,000 31,000
Drosophila 137,000,000 13,500
C. Elegans 96,000,000 19,000
Yeast 12,000,000 6,315
E. Coli 5,000,000 5,361
smallest Genome ??????
genes

Cells
Humans
60 trillion (1012) cells
320 cell types

The original Watson and Crick’s paper

The central dogma of molecular biology
DNA RNA proteintranscription translation

PCR = Polymerase Chain Reaction

Silicon PCR chamber

Capillary Electrophoresis

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Introduction
Packaging
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Packaging of MEMS
Packaging of MEMS converts a machined structure into a useful
assembly that can safely and reliable interact with its environment
Definition of MEMS packaging is broad because each application is
unique in its packaging requirements
Function =
Protect the micro machined structure to a broadening range of
environments. It must also provide interconnections toelectrical signals,
electrical interconnect, access to environment and interaction with
environment

Packaging Hierarchy
(level of packaging)

Package Functions
- Power distribution
- Signal distribution
- Heat dissipation
- Protection
- Manufacturability /
Processing of
Components

Typical MEMS packaging process flow

Saw and Dice wafer
In a FAB thousands of micro structures are made simultaneously.
Dicing separates the structures into individual components
Most common is a diamond saw with 75 - 250 micron thick
blades, The wafer is held by a blue colored sticky tape and
the wafer is cooled continuously
Potential damaging of the structure during the process
Sometimes the last sacrificial etching is done after dicing

Process Flow Wire Bonding

Characteristics Flip Chip Bonding
Flip Chip implies bonding the die face down. Electrical contacts are
made by means of plated bumps between bond pads on the die and
metal pads on the package substrate. The attachment is intimate with
small spaces (50 - 200 micron) between the die and the package. The
pads can be all over the surface of the die (area arrays) resulting in an
increase in density of (I/Os)
Inductance of a solder bump
is less than 0.05 nH compared
to 1 nH for a 125 micron long
and 25 micro thick wire bond

Thermal Condsiderations
More complex chips make more demands on efficient heat removal
from the chips.
Silicon chips limited to approximately 100ºC for normal operation
which limits power densities on chip to a maximum of 10watts/cm2
in current IC packages.
Imposes a limit average on power dissipation per individual circuit
on chip of approximately 1µW/circuit for a 10 million transistor chip
of area 1cm × 1 cm.

Thermomechanical Considerations
Important to reduce power dissipation/circuit and improve package
thermal design in order to produce larger, more complex ICs in the
future.
Differential thermal expansion of package parts gives rise to
mechanical stresses and reliability risks.
E.g. Coffin Manson behaviour
# cycles before failure = Function ( thickness / T *  CTE)

Package Sealing and Encapsulation
Intended to protect the chip and package metallisation from corroding
environments and from mechanical damage due to handling.
Moisture is one of the major sources of corrosion.
Plastic materials, such as silicones and epoxies, developed with low water
diffusion properties are used extensively for IC encapsulation.
For high reliability devices hermetic sealing used based on welding or brazing
of ceramic/metal packages. More expensive and time-consuming than plastic
encapsulation

Protective coating and media isolation
Coatings are often used in flow sensors and pressure sensors.
- in cars salt water sprays, acid rain polutants can attack the sensor
- home applyances oftengive alkaline environments
An often used coating is parylene ( p-xylylene) which can
be deposited at room temperature and gives a conformal
coating resistant to: exhaust gasses, fuel, salt spray,
water, alcohol, organic solvents.
Strong acids and bases dissolve parylene

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Thermal Shock
Thermal
Humidity
Corrosive
Dust
Vibration
Power Cycling
Voltage Margining
Frequency Margining
Relative Causes for Failure in Electronics

Characteristics of Ceramic Packaging
Ceramics are hard and brittle materials made by shaping a nonmetalic
mineral, then firing at high temperatures for densification. Most
ceramics are electrical insulators and good thermal conductors

Process Flow Ceramic Package

Ceramic Packaging of DMD
The DMD package is a ceramic package.
A DMD sells for several hundred dollars.
An accelerometer packaged in ceramic would cost 35 USD, a plastic
packaged accelerometer only 2-4USD

Capping

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Thin Film Capping

Metal Package
Metal packages are attractive for MEMS because they can be
prototyped in small series and are hermetic. Disadvantage is the
high costs relative to plastic

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Plastic Packaging

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Ceramic Package

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Optical Package

Molded plastic packaging
Post molded: plastic is molded after the die is attached to a lead
frame (process subject die and interconnect to harsh molding
conditions)
A major disadvantage of plastic
packages is hat they are not
hermetic
Yet in traditional electronics plastic
packages are prefered:
low cost few pennies per pin
high reliability: one failure
per billion hours operating time

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Plastic Cap for MEMS
Feasibility of polymers for wafer scale packaging of RF MEMS
P.J. Bolt, J.E. Bullema, R. Korbee, 4M, Cardiff 2008

3D - Packaging
3D Technology according to Suss

3D - Packaging
(e.g. MEMS Scale Package)
J.E. Bullema, M.H.M. Meuwissen, E.P. Veninga, " Design Study for Stacked MEMS",
Proceedings Eurosime 2003, Key note Paper, 30 March - 2 April 2003, p279..283,

3D - Packaging
Typical System in Package in 2010 [Wolf,2007]

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Tire Pressure Sensor
(FHG – IZM)

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TX on micro processor
(FHG – IZM)

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RF sensor with TSV
(Omron)

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RF sensor with TSV
(Omron)

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Future MEMS Packaging with TSV

Introduction
Packaging
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Wrap - Up
Some Collective Multiple Choise
A typical proof mass of an accelerometer is in the range of:
A 10 micro gram to 100 micro gram
B 100 micro gram to 1 milligram
C 1 micro gram to 100 micro gram
D 0,1 micro gram to 100 micro gram

2011 Introduction micro and nanotechnology

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2011 Introduction micro and nanotechnology