EE 5349 Section 5 Microsystems

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EE 5349 Section 5 Microsystems

• Lectures MonWed, 230-350 pm, NH 109
• Instructor Dan Popa, Ph.D., Assistant Professor,
  EE
• Office hours MonWed 1000 am 1200 pm, NH525
• Course info http//arri.uta.edu/popa/micro
• Grading policy
• 5 Homeworks 25
• Midterm (in-class) 25
• Course project 25
• Final (in-class) 25

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Syllabus

• Part 1 Introduction to small things
• Week 1 August 24, 26, Lectures 1, 2
• Introduction to microsystems, brief history.
• Example MST classification and examples.
• Modeling of microsystems - what is different
  (scaling laws)?
• Week 2 August 31, September 2 Lectures 3, 4
• Modeling Refresher in continuum mechanics
  mechanics of beams, plates, statics, dynamics,
  electrostatics, electromagnetics, fluid dynamics,
  heat conduction, MATLAB simulation.
• Week 3 September 9, Lecture 5
• Modeling More on scaling laws.
• Homework 1 posted September 9.
• Week 4 September 14, 16, Lectures 6,7
• - Modeling More on scaling laws.
• Week 5 September 21, 23, Lectures 8,9
• Fundamental concepts in precision design
  kinematics, constraints, alignment, flextures,
  error compensation, nanometric measurement
  principles
• Homework 2 posted on September 23.

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Syllabus

• Part 2 Microfabrication
• Week 6 September 28, 30, Lectures 10,11
• Fabrication Basics of Lithography, Wet and Dry
  Etching and Deposition
• Examples Micromachined devices.
• Week 7 October 5, 7 Lectures 12,13
• Fabrication EDM and Laser Micromachining.
• Homework 3 posted on Oct. 7
• Week 8 October 12, 14 Lectures 14,15
• Fabrication LIGA and Micromolding.
• Homework 3 posted on Oct. 7
• Week 9 October 19, 21 Lectures 16,17
• Fabrication Surface Micromachining
• Homework 4 posted on Oct 21
• Midterm 1 (in class), October 21

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Syllabus

• Part 3 Modeling and Control of Microactuators
• Week 10 October 26, 28 Lectures 18, 19
• Modeling Microsystems layout basics design
  rules, tools, formats, examples.
• Modeling Microsystems modeling and simulation
  tools.
• Week 11 November 2, 4 Lectures 20, 21
• Modeling Simulation of Microactuators using
  SUGAR.
• Modeling Reduced Order MEMS Models,
  Eectrothermal microactuators.
• Homework 5 posted Nov. 4
• Week 12 November 9, 11, Lectures 22, 23
• Modeling Electrostatic Microactuators and
  MEMS Control
• Week 13 November 16, 18, Lectures 24, 25
• Modeling Piezoelectric, SMA, and Magnetic
  actuators

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Syllabus

• Part 4 Microassembly, Micropackaging
• Week 14 November 23, 25, Lectures 26, 27
• Backend Introduction to microassembly and
  microrobotics.
• Example Microfluidic and Microoptical systems.
• Week 15 November 30, December 2, Lectures 28,
  29
• Backend Introduction to microsystems packaging.
• Course project due Dec. 2 with presentation
• Week 16 December 7, 11
• Final Exam (In-class, comprehensive) Dec 7.

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Syllabus

• Grading policy on curve
• Homeworks 5. Homeworks contain both written
  and/or computer simulations using MATLAB. Submit
  code if it is part of the assignments.
• Reading Assignments After each course. The
  assigned reading material is given out in order
  to make you better understand the concepts.
  Materials from the reading assignments may be
  part of course exams.
• Examinations One midterm (in class) and one
  final (in class).
• Course project Due on Dec 2, with a report and
  an in-class presentation. This project requires
  students to focus on a microsystem from a list
  provided in class, and walk through details
  related to its manufacturing and
  characterization. Students should identify
  suitable materials, designs, models, and
  processes to manufacture the microsystem and
  report their findings in a 8-10 page research
  report.

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Textbooks

• Modeling MEMS and NEMS, by J.A. Pelesko, D. H.
  Bernstein, Publisher ChapmanHall/CRC Press,
  2003, ISBN 1-59488-306-5 (required)
• Fundamentals of Microfabrication, by Marc J.
  Madou, Second Ed., Publisher CRC Press, 2002,
  ISBN 0-8493-0826-7 (required)
• Microsystem Technology and Microrobotics, by S.
  Fatikow, U. Rembold, Publisher Springer-Verlag,
  1997, ISBN 3-540-605658-0 (recommended, on
  library reserve)
• Fundamentals of Microsystems Packaging, by Rao
  Tummala (Ed.), Publisher McGraw Hill, 2001,
  ISBN 0-07-137169-9 (recommended, on library
  reserve)
• Foundations of Ultraprecision Mechanism Design,
  by St. Smith, D.G. Chetwynd, Publisher CRC
  Press, 1992, ISBN 2-88449-001-9 (recommended, on
  library reserve)
• Fundamentals and Applications of Microfluidics,
  Second Edition (Integrated Microsystems), by
  Nam-Trung Nguyen, Steven T. Wereley, Publisher
  Artech House Publishers, 2006,  ISBN 1580539726
  (recommended, on library reserve)

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Course Tools

• Math linear/matrix algebra, trigonometry,
  differential equations (ODE and PDE).
• Physics thermodynamics, mechanics of plates,
  electrostatics.
• Programming MATLAB.
• UC Berkeley SUGAR 2.0 for MATLAB, available for
  download
• http//www-bsac.eecs.berkeley.edu/cadtools/sugar/s
  ugar

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Honor Code

• Missed deadlines for take-home exams and
  homeworks Maximum grade drops 10 per late day.
  Speak to me about missed deadlines for full
  credit in extenuating circumstances.
• Academic Dishonesty will not be tolerated. All
  homeworks and exams are individual assignments.
  Your take-home exams and homeworks will be
  carefully scrutinized to ensure a fair grade for
  everyone.
• Attendance and Drop Policy Attendance is not
  mandatory. However, if you skip classes, you will
  find the homework and exams more difficult.
  Assignments are going to be posted here, however,
  due to the pace of the lectures, copying someone
  else's notes may be an unreliable way of making
  up an absence. You are responsible for all
  material covered in class regardless of absences.

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Lecture 1 Intro to Microsystems

• Course Outline
• Microsystems vs. MEMS.
• Brief history.
• Basic concepts what this course covers.

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What is a microsystem?

• A system with dimensions generally between 1µm
  and 1mm at the functional device level, and 1mm
  to 1cm at the system level.
• System scaling Expressed in terms of part size,
  tolerance or positioning accuracy. Definition
  taking into account the types of instruments
  needed for visualization.
• Nano Part sizes below 500nm, positioning
  accuracy below 250nm, SEM/TEM.
• Micro Part sizes between 0.5 µm and 500 µm,
  accuracy between 0.25 µm and 2.5 µm, optical
  microscope.
• Meso Part sizes between 500 µm and 5 cm,
  accuracy between 2.5 µm and 25 µm, regular
  optics.
• Macro Part sizes greater than 5 cm, accuracy
  greater than 25 µm, regular optics.
• Special cases where not all 3 dimensions are in
  the same size scale, for example optical fibers
  or thin substrates.

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Microsystems examples

• Examples in nature abound
• living cells
• capillary blood vessels
• small insects (e.g. fruit fly)
• Examples of older man-made systems
• Watches
• Microdrills at your dentist office
• Thin films for your sunglasses
• Examples of recent man-made microsystems
• Microfluidic microTAS (Lab-on-Chip).
• Microoptic micromirror array (DMD).
• Micromechanic microaccelerometers (air-bags).
• Microsensors gas and pressure transducers.

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Why small is different

• Micromachines are governed by the same physical
  equations as macromachines, but solutions of
  these equations have different dominant effects.
• These effects sometimes work in favor of a
  microsystem (for instance devices are lighter,
  faster, consume less power). Sometimes they work
  against MST (less force, harnessing less power,
  etc).
• Quantifying these effects is done though
  so-called scaling laws, where the variable of
  interest (e.g. mass, power, temperature, force)
  is expressed in terms of the device scale
• OutputKrn, n scaling factor, r device length
  scale, K- constant.
• Most important scaling law is a result of the
  ratio between surface and volume. At small
  scales, surface effects become dominant.
• V4/3?r3, A?r2, V/AO(r), therefore VltltA if
  rltlt1.
• Example of surface effects electrostatic
  attraction of plates
• Example of volumetric effects gravitational
  force.
• In this course we will look at solutions
  governing the evolution of microsystems and
  derive appropriate approximations for their
  length scales. We study the scaling of
  mechanical, electrical, thermal, optical and
  fluidic physical laws.

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Microsystems VS. MEMS

• MEMS/MOEMS Microelectromechanical,
  Microoptoelectromechanical systems
• Term coined in the 1980s in the US using
  fabrication technology similar to the IC
  semiconductor industry.
• MST Microsystems Technology
• Terms used mostly in Europe to denote
  miniaturized devices and associated technology.
• Micromachines
• Term used mostly in Japan to denote miniaturized
  machines and systems, including those used to
  manufacture.
• MEMS is a subset of MST, as it includes
• Non-Silicon materials
• Non-IC fabrication methods
• Precision engineering concepts
• In this course we focus on MST rather than just
  MEMS.

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Why making small things is a lot harder than
making conventional things
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Brief History of Microsystems (USA)

• Invention of the transistor at Bell Telephone
  Laboratories in 1947 sparked a fast-growing
  microelectronic technology. Jack Kilby of Texas
  Instruments built the first integrated circuit
  (IC) in 1958 using germanium (Ge) devices. It
  consisted of one transistor, three resistors, and
  one capacitor. The IC was implemented on a sliver
  of Ge that was glued on a glass slide. Later that
  same year Robert Noyce of Fairchild Semiconductor
  announced the development of a planar
  double-diffused Si IC. The complete transition
  from the original Ge transistors with grown and
  alloyed junctions to silicon (Si) planar
  double-diffused devices took about 10 years. The
  success of Si as an electronic material was due
  partly to its wide availability from silicon
  dioxide (SiO2) (sand), resulting in potentially
  lower material costs relative to other
  semiconductors. Since 1970, the complexity of ICs
  has doubled every two to three years. The minimum
  dimension of manufactured devices and ICs has
  decreased from 20 microns to the sub micron
  levels of today. Current ultra-large-scale-integra
  tion (ULSI) technology enables the fabrication of
  more than 10 million transistors and capacitors
  on a typical chip.
• Richard Feynman delivers his famous lecture
  There is Plenty of Room at The Bottom, in which
  he notes that in 40 years from now. Feynman
  considered a number of interesting ramifications
  of a general ability to manipulate matter on an
  atomic scale. He was particularly interested in
  the possibilities of denser computer circuitry,
  and microscopes which could see things much
  smaller than is possible with scanning electron
  microscopes. These ideas were later realized by
  the use of the scanning tunneling microscope
  (1982) and the atomic force microscope (1986).
  Feynman also suggested that it should be
  possible, in principle, to do chemical synthesis
  by mechanical manipulation, and he presented the
  "weird possibility" of 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.
• K. Eric Drexler reuses Feynmans ideas in the
  context of Molecular Manufacturing in 1981. He
  introduced the concept of a billion tiny
  factories and added the idea that they could make
  more copies of themselves, via computer control
  instead of control by a human operator, in his
  1986 book Engines of Creation The Coming Era of
  Nanotechnology. Carbon nanotubes were invented
  prior to Sumio Iijimas Nature paper that brought
  them in focus in 1991, and mass-produced in 1996
  by Richard Smalley at Rice University.

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Brief History of Microsystems (USA)

• Attention was first focused on microsensor (i.e.,
  microfabricated sensor) development. The first
  microsensor, which has also been the most
  successful, was the Si pressure sensor. In 1954
  it was discovered that the piezoresistive effect
  in Ge and Si had the potential to produce Ge and
  Si strain gauges with a gauge factor (i.e.,
  instrument sensitivity) 10 to 20 times greater
  than those based on metal films. As a result, Si
  strain gauges began to be developed commercially
  in 1958. The first high-volume pressure sensor
  was marketed by National Semiconductor in 1974.
• Around 1982, the term micromachining came into
  use to designate the fabrication of
  micromechanical parts (such as pressure-sensor
  diaphragms or accelerometer suspension beams) for
  Si microsensors. The micromechanical parts were
  fabricated by selectively etching areas of the Si
  substrate away in order to leave behind the
  desired geometries. Isotropic etching of Si was
  developed in the early 1960s for transistor
  fabrication. Anisotropic etching of Si then came
  about in 1967. Various etch-stop techniques were
  subsequently developed to provide further process
  flexibility. The first micromachined
  accelerometer is developed at Stanford by
  Roylance et. al.
• Among these is the sacrificial layer technique,
  first demonstrated in 1965 by Nathanson and
  Wickstrom, in which a layer of material is
  deposited between structural layers for
  mechanical separation and isolation. This layer
  is removed during the release etch to free the
  structural layers and to allow mechanical devices
  to move relative to the substrate. A layer is
  releasable when a sacrificial layer separates it
  from the substrate. The application of the
  sacrificial layer technique to micromachining in
  1985 gave rise to surface micromachining, in
  which the Si substrate is primarily used as a
  mechanical support upon which the micromechanical
  elements are fabricated.
• Prior to 1987, these micromechanical structures
  were limited in motion. During 1987-1988, a
  turning point was reached in micromachining when,
  for the first time, techniques for integrated
  fabrication of mechanisms (i.e. rigid bodies
  connected by joints for transmitting,
  controlling, or constraining relative movement)
  on Si were demonstrated. During a series of three
  separate workshops on microdynamics held in 1987,
  the term MEMS was coined.

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Microsystems by market volume

• Largest Current Markets Inkjet, Pressure
  sensors, DLP, Inertial Sensors

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Top 30 Manufacturers (2003)
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Anatomy of a Microsystem
Sensors
Actuators

Applications Automotive Optics Telecom Biomedical
Technology (Design) System Tech. (Fab) Micro
Tech. (Si, non-Si) Materials Tech. (Package)
Process Tech.
µSystem
Processors
Optical Electrical Mechanical Thermal Fluid Magnet
ic Electromagnetic
Interface toEnvironment
D/A
µactuator
µSystem
A/D
µsensor
Control
µprocessor
InformationEnergySubstancesmove across a
microsystem
µelectronics
Signals, Power
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What this course covers

• Micro System Technology Concepts
• Design, simulation, control (device and system
  level)
• Interconnects, packaging
• Assembly precision concepts
• Micro Fabrication Concepts
• Si and Non-Si machining
• Materials and Effects
• Thermal, Electrostatic, Piezo, SMA, Fluidics,
  etc.
• MST Examples

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Readings

• http//www.its.caltech.edu/feynman/plenty.html
• http//www-crim.sssup.it/download/papers/2000/eure
  l2000.pdf
• Chapter 1 from Pelesko Text