Microtechnology: Wikis

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From Wikipedia, the free encyclopedia

Microtechnology is technology with features near one micrometre (one millionth of a metre, or 10-6 metre, or 1μm).

In the 1960s, scientists learned that by arraying large numbers of microscopic transistors on a single chip, microelectronic circuits could be built that dramatically improved performance, functionality, and reliability, all while reducing cost and increasing volume. This development led to the Information Revolution.

More recently, scientists have learned that not only electrical devices, but also mechanical devices, may be miniaturized and batch-fabricated, promising the same benefits to the mechanical world as integrated circuit technology has given to the electrical world. While electronics now provide the ‘brains’ for today’s advanced systems and products, micromechanical devices can provide the sensors and actuators — the eyes and ears, hands and feet — which interface to the outside world.

Today, micromechanical devices are the key components in a wide range of products such as automobile airbags, ink-jet printers, blood pressure monitors, and projection display systems. It seems clear that in the not-too-distant future these devices will be as pervasive as electronics.

Contents

Micro electromechanical systems

An etched silicon wafer

The term MEMS, for Micro Electro Mechanical Systems, was coined in the 1980’s to describe new, sophisticated mechanical systems on a chip, such as micro electric motors, resonators, gears, and so on. Today, the term MEMS in practice is used to refer to any microscopic device with a mechanical function, which can be fabricated in a batch process (for example, an array of microscopic gears fabricated on a microchip would be considered a MEMS device but a tiny laser-machined stent or watch component would not). In Europe, the term MST for Micro System Technology is preferred, and in Japan MEMS are simply referred to as "micromachines". The distinctions in these terms are relatively minor and are often used interchangeably.

Though MEMS processes are generally classified into a number of categories – such as surface machining, bulk machining, LIGA, and EFAB – there are indeed thousands of different MEMS processes. Some produce fairly simple geometries, while others offer more complex 3-D geometries and more versatility. A company making accelerometers for airbags would need a completely different design and process to produce an accelerometer for inertial navigation. Changing from an accelerometer to another inertial device such as a gyroscope requires an even greater change in design and process, and most likely a completely different fabrication facility and engineering team.

MEMS technology has generated a tremendous amount of excitement, due to the vast range of important applications where MEMS can offer previously unattainable performance and reliability standards. In an age where everything must be smaller, faster, and cheaper, MEMS offers a compelling solution. MEMS have already had a profound impact on certain applications such as automotive sensors and inkjet printers. The emerging MEMS industry is already a multi-billion dollar market. It is expected to grow rapidly and become one of the major industries of the 21st century. Cahners In-Stat Group has projected sales of MEMS to reach $12B by 2005. The European NEXUS group projects even larger revenues, using a more inclusive definition of MEMS.

Microtechnology is often constructed using photolithography. Lightwaves are focused through a mask onto a surface. They solidify a chemical film. The soft, unexposed parts of the film are washed away. Then acid etches away the material not protected.

Microtechnology's most famous success is the integrated circuit. It has also been used to construct micromachinery.

Items constructed at the microscopic level

The following items have been constructed on a scale of 1 micrometre using photolithography:

External links

See also

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Wikibooks

Up to date as of January 23, 2010

From Wikibooks, the open-content textbooks collection

Infobox/Microtechnology

The Opensource Handbook of Microfabrication and Microtechnology Development stage: 25% (as of {{{2}}})

The Wikibook on Microtechnology has been started with the intention to gather information in one place about the various applications, fabrication methods and systems to provide students, researchers and everyone else an open-source handbook and overview guide.

Two microgrippers.jpg

Material is continuously being added to this book -join the effort to create it! Overview Tables:
Encourage the authors -use the discussion page There is a related book on Nanotechnology.
Latest major addition: Semiconductor Electronic Properties Google Search in this book

_

Contents Detailed descriptions (Development stage: 100% (as of {{{2}}})-icons are individual web pages; Numbers are sub-sections)

Part 1: INTRODUCTION

What is microtechnology about - what can you use it for and where is it going?


Development stage: 50% (as of {{{2}}}) Introduction

  1. A Perspective on Microtechnology
  2. Applications of Microtechnology

Development stage: 50% (as of {{{2}}}) Overviews

  1. Internet Resources
  2. Journals
  3. Microtech Products & Companies
  4. A Micro-technology Timeline

Development stage: 50% (as of {{{2}}}) About the Book

  1. Vision
  2. How to Contribute
  3. History
  4. Authors
  5. Support and Acknowledgements

Development stage: 25% (as of {{{2}}}) Reaching Out

  1. Outreach Projects
  2. Demonstration Experiments
  3. Teaching Microtechnology

Part 2: MATERIALS

Silicon is the traditional microfabrication material for making computer chips and other electronic circuits. A wealth of other material types are being increasingly used for lab-on-a-chip systems and cheap disposable circuits.


Development stage: 25% (as of {{{2}}}) Materials

  1. Overview
  2. Applications and Uses
  3. Product Life-Cycles
  4. Environmental Considerations
  5. Wafers and Substrates Overview

Development stage: 25% (as of {{{2}}}) Semiconductors

  1. Silicon
  2. Polycrystalline Silicon
  3. IV Semiconductors
  4. III-V Semiconductors
  5. II-VI Semiconductors

Development stage: 25% (as of {{{2}}}) Insulators

  1. Silicon Dioxide
  2. Silicon Nitride
  3. PMMA
  4. PDMS
  5. SU8

Development stage: 25% (as of {{{2}}}) Conductors

  1. Noble Metals
  2. Alloys
  3. Silicides

Part 3: FABRICATION PROCESSES

Microfabrication is largely concerned with making microchips by batch processing silicon (and an increasing number of different materials) wafers into individual chips in a cleanroom facility. Cleanrooms are used because dust must be avoided. The parts of a microchip are much smaller than the average dust particle, and a single particle can wreak havoc in a sensitive process (not only making a fault at some point on the wafer, but also contaminating process equipment) The processes can roughly be divided into Additive and etching processes that wither add or remove material, and lithography that creates patterns on the surface.


Development stage: 50% (as of {{{2}}}) Additive Processes

  1. Overview
  2. Oxidation
  3. Chemical Vapor Deposition (CVD)
  4. Physical Vapor Deposition (PVD)
  5. Epitaxial Growth
  6. Electrochemical Methods
  7. Spinning
  8. Surface Functionalization

Development stage: 50% (as of {{{2}}}) Etching Processes

  1. Etchants
  2. Wet Etch Overview Table
  3. Wet Etch Compatibility Chart
  4. Capillary Effects
  5. Silicon KOH Etch
  6. Silicon Oxide Etch (HF, BHF, BOE)
  7. Silicon Nitride Etch
  8. Metal Etches
  9. Cleaning Methods
  10. Dry Etching Overview
  11. Reactive Ion Etching (RIE, DRIE, ASE)
  12. Dry Cleaning Methods (Plasma, Ozone)
  13. Laser Ablation
  14. Gas Etches

Development stage: 25% (as of {{{2}}}) Lithography

  1. Ultra Violet Lithography (UVL)
  2. Electron Beam Lithography (EBL)
  3. Resist Coatings

Development stage: 25% (as of {{{2}}}) Additional Methods

  1. Rapid Thermal Anneal (RTA)
  2. Wafer Bonding
  3. Electrical Connections
  4. Doping
  5. Packaging
  6. Ellipsometry
  7. 4 Point Measurements
  8. Atomic Force Microscopy
  9. Scanning Electron Microscopy
  10. Optical Microscopy
  11. Vacuum Equipment

Part 4: APPLICATIONS

Reading this, you are quite used to your computer which is based on microelectronics, you access the internet which would not work well without photonics. The airbag sensor in you car is a MEMS devices and shortly you will also find lab-on-a-chip devices in your everyday life.


Development stage: 25% (as of {{{2}}}) Microelectronics

  1. An Ohmic Resistor
  2. The Diode
  3. The Transistor
  4. CMOS

Development stage: 25% (as of {{{2}}}) Photonics

  1. Waveguides
  2. Photonic Band Gap Structures
  3. Electro-optical Devices

Development stage: 50% (as of {{{2}}}) Micro-electromechanical Systems (MEMS)

  1. Applications
  2. Resonators
  3. Strain Gauges
  4. Pressure Sensors
  5. AFM cantilevers
  6. Acceleration Detectors
  7. Optical Beam Control
  8. RF MEMS

Development stage: 25% (as of {{{2}}}) Microfluidics and Sensors

  1. Applications
  2. Microfluidic Pumps
  3. Microfluidic Valves
  4. Chemical Noses
  5. PCR Systems
  6. Microfluidic Cell Handling
Microtechnology Demonstration Experiments in the ScienceShow Wikibook

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