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PHYS 534 (Fall 2008)Module on Microsystems & Microfabrication

Lecture 1

Introduction to Microdevices

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and Microsystems

Srikar Vengallatore, McGill University

Outline of Lecture

•Introduction to Microsystems

-Basic definitions and examples

-How are they designed?

-How are they manufactured?

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Introduction to Microsystems

Micro: Small SystemInput Output

•System dimensions: 1 mm to 10 cm

•Structural components: 10 nm to 100 μm

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•Designed and manufactured to performuseful activity

LENGTH SCALES

10-3 m = 1 mm

10-4 m = 100 μm

10-5 m = 10 μm

10-6 m = 1 μm

10-7 m = 100 nm Molecules

Bacteria STRUCTURESFOR

MICROSYSTEMS

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10-8 m = 10 nm

10-9 m = 1 nm

10-10 m = 0.1 nm

Atoms

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1 m

1 μm

1 mm

51 nm

1 μm

Source: Kalpakjian and Schmid

Example 1.Integrated Circuit

>1 Million wires per cm2 !>1 Million wires per cm2 !

•No moving parts

•$200 Billion per year

•Revolutionary

6(I.B.M)

Revolutionary(Internet, computers,…)

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Cross-Section of an I.B.M Integrated Circuit

Copper

Silicon dioxide

7Silicon

Tungsten

1 μm

Example 2: Texas Instruments Micromirrors

11 μm

8DIGITAL LIGHT PROCESSING (DLP)

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9

TorsionalHi

Electron Micrograph of Texas Instruments DMD

Hinge

10www.dlp.com

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Samsung DLP TVsDLP Projectors

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7

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Some TerminologyMicrosystems are known by many names…..

•Microdevices•MicroelectronicsMi l t h i l S t (MEMS)•Microelectromechanical Systems (MEMS)

•Microsystems Technology (MST)•Microfluidic systems•Micro total analysis systems (micro-TAS)•Bio-MEMS/ Bio-microsystems•Optical MEMS/ Optical microsystems

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•Optical-MEMS/ Optical microsystems•RF-MEMS (for radio-frequency MEMS)•Power MEMS (micro-engines, micro fuel cells)•…

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Terminology Reflects Evolution of Technology

•In the beginning, there was the transistor…..

Invented in 1947 in

…Nothing micro yet!

Bell Labs.

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Walter BrattainJohn BardeenWilliam Shockley

Nobel Prize in Physics(1956)

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Use of a Transistor in an Electrical Circuit

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Jack Kilby, Texas Instruments

The World’s First Integrated Circuit

Aluminum Wires(Interconnects)

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•Robert Noyce

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Kilby: Nobel Prize for Physics (2000)

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Robert Noyce(co-founder of Intel)

Evolution of Integrated Circuits (1950 – 2000)

Year # of Transistors per device

1960 < 100

1970 104 (4004 8008)1970 104 (4004, 8008)

1980 105 (386 processor)

1990 106 (486 processor)

1992 2 x 106 (Pentium processor)

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1992 2 x 10 (Pentium processor)

1996 107 (Pentium II)

2000 108 (Pentium 4)

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Stage 2: From Microelectronics to Micromechanics

1970s: Realization that mechanical components can also be miniaturized

Emergence of micromachined pressure g psensors

Sealed Vacuum CavityMembrane

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Pressure Port (P)

•Estimate pressureby measuring deflection

Pressure Sensors: Principle of Operation

8 mm

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Micromachined Pressure Sensors are now Widely Used

23www.issys-mems.com

1980s: Micro Sensors and Actuators•Sensors for force, acceleration, pressure, mass,….

Micromachined Accelerometers

24~8 million accelerometers are manufactured each year

Analog Devices

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mk F ma ka δ= ⎫⇒ =⎬

Principle of Operation of Accelerometer

aa

F k mδ⇒ =⎬= ⎭

δ

Quasi-Static Accelerometer

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Applications for Micromachined Accelerometers

•Modal analysis of vibratory systems

•Navigation

•Crash Sensors: Air-bag deployment in automobiles

•Protection of hard-disks in laptop computers

•Video games

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•……..

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1980s Micro Actuators: Motion in Microsystems

Linear

ELECTROSTATIC ACTUATORS

Gap, g0

LinearSpring, k

Mass, m

g < g0V+

_

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Fixed electrode

Micro Electro + Mechanical System, or MEMS

Types of Microscale Actuators

• Electrostatic

• Thermal

• Piezoelectric

• Shape Memory Alloy

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Motion is either due to Applied Forces orDifferential Expansion and Contraction

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α1

α2

THERMAL ACTUATORS

α2 α2α1 >

Heat

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1990s: Increasing Focus on Commercialization

Important Trends

•Microsystem community focused on Utility(design, manufacture, marketing, reliability, cost, etc.)

•Range expanded from Electro + Mechanical to multipleenergy domains

•Optical•Chemical•Radio-Frequency communications

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•Biological•Fluidic•…

There is a complete world of engineering at these scales!

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OPTICAL MICROSYSTEMS FOR DISPLAYS

Silicon Light Machines

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OPTICAL MICROSYSTEMS FOR COMMUNICATIONS

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OPTICAL CROSS-CONNECTS

33Lucent

OPTICAL MICROSYSTEMS FOR SENSING

POLYCHROMATOR

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10 μm

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1990s: Microfluidics and Bio-Microsystems

Texas Instruments

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D. Therriault, Ecole Polytechnique

Microfluidic Networks

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1990s: Micro Needles for Painless Drug Delivery

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Georgia Institute of Technology

IMPLANTABLE CHIPS FOR PROGRAMMED DRUG DELIVERY

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39Microchips

EMERGING APPLICATIONS: PORTABLE POWER GENERATION

Direct MethanolFuel cell

40Toshiba

•12 W @ 11 V for 5 hours with one cartridge•No recharge times

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Micro Gas Turbine Engine

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MIT

Micro Solid-Oxide Fuel Cells

Anode (NiO-YSZ)

Cathode (LSM)

Électrolyte (YSZ)

42McGill University/Ecole Polytechnique

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Refining our Terminology

In this course, we will use MICROSYSTEMS as a synonym for

•Microdevices•Microelectronics•Microelectromechanical Systems (MEMS)•Microsystems Technology (MST)•Microfluidic systems•Micro total analysis systems (micro-TAS)•Bio-MEMS/ Bio-microsystemsO ti l MEMS/ O ti l i t

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•Optical-MEMS/ Optical microsystems•RF-MEMS (for radio-frequency MEMS)•Power MEMS (micro-engines, micro fuel cells)•…

Microsystems are useful….

•Computation•Information storage & display•Optical telecommunications •Sensing (force, mass, acceleration, chemistry, biology,….)•Actuator technology •Portable power generation•Energy storage•Microscale chemical synthesis and analysis

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•Medical diagnostics•Therapeutics (drug delivery)•…..

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Estimated Global Market for Microsystems

Device Applications Market

Integrated Information & >$250 BillionCircuits Communications

Ink-Jet PrintersNozzles

Accelerometers AutomobilesPressureSensors

~$10 billion

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Sensors

DNA Microarrays Genome sequencing

Drug delivery, fuel cells, microneedles, etc. (in advanced stages of commercialization)

Outline of Lecture

•Introduction to Microsystems

-Basic definitions and examples

-How are they designed?

-How are they manufactured?

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How are they Designed?

•Formulate a plan to satisfy a need or solve a problem*.

If this plan results in the creation of something having a physical reality, then the product must be:

-Functional

-Safe

-Reliable

-Competitive

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-Usable

-Manufacturable

-Marketable

*JE Shigley, CR Mischke & RG Budynas, Mechanical Engineering Design

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Ashby’s Approach to Design

Market need

C tEvaluationCreativity

Concept

Embodiment

D t il

of competitiony

& experience

Behavioralmodels

Manufacturingconsiderations

In house Management

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Product Specification

DetailIn-house expertise

Managementdecisions

Modeling and Analysis of Microsystems

•Microsystems operate in multiple energy domains(mechanical, fluidic, electrostatic, thermal, magnetic,…)

•Frequently, coupling between different domains(electromechanical; thermoelastic; magnetomechanical,..)

•Critical question: validity of continuum physics

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Approach to Structural Design

•What kind of STRUCTURES (Machine elements) to use?Beams, plates, rods, or membranes?Solid section or shaped cross-section?pMonolithic or composite?Electrostatic or electrothermal actuation?

•What kind of MATERIALS to use?Ceramics, metals, or polymers?Fiber-reinforced composites or layered composites?

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…

Structural Design is Constrained by Manufacturing Limitations

How are they manufactured?

•Starting MaterialFlat Plate (substrate; wafer)

•Add material

•Pattern transfer

•Remove Material

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Pattern transfer(Photolithography)

•Package microdevice!

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Patterning

Starting Material: Substrate (wafer)

Overview of Microdevice Manufacture

PhotolithographyE-beam lithography

Processes

g

Additive Processes

SubtractiveProcesses

EvaporationSputteringCVDElectrodeposition

g p yIon beam lithographySoft lithography

Wet etchingDry etchingPlasma etching

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Package Microdevice

ElectrodepositionWafer bondingDRIE

Polishing

Catalog of Manufacturing Processes

Patterning Techniques: Photolithography, Microstamping,Electron/ion beam lithography,Soft lithography,…

Additive processes: Thin-film deposition, wafer bonding,oxidation, epitaxy, …..

Subtractive processes: Wet etching, dry etching, ion milling,

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p g, y g, g,deep reactive ion etching,…

We will study these processes in GREAT DETAIL!

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Where are they Made (Fabricated) ?

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•Need Clean Room Fabrication Facilities (Fabs)Micromachining = Microfabrication = Microdevice Manufacture

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NanoTools Microfabrication Facility at McGill University

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•Basement of the Rutherford Physics Building

58Images courtesy of Sandia National Laboratories

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Fundamentally Different Approach to Manufacturing

•Parallel manufacture of hundreds of devices

•Simultaneous manufacture & assembly of components

•Layer-by-layer manufacture

596x106 moving parts106 mirrors

Objective of this Module: Manufacturing of Microsystems

•This is an area of very active research

•Focus on: Fundamental principles + Established methods•Focus on: Fundamental principles + Established methods

•Science lags behind technology(We will use it even if we don’t understand why it works!)

•Learn ideas, but also some crucial details

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•Learn by assimilation: Case Studies

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Market Need

System concept StructuralEmbodimentDesign

R i t

MECH 553: Design and Manufacture of Microdevices

Device concept

StructuralEmbodiment

DetailsAdditive Processes Subtractive

RequirementsProcessConstraints

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Details

Pattern formation(Photolithography)

Processes(Thin film deposition)

processes (Etching)

Processes

Microdevice