MEMS .

• MEMS

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Microelectromechanical systems - Materials for MEMS manufacturing

1 The fabrication of MEMS evolved from the process technology in

semiconductor device fabrication, i.e. the basic techniques are deposition

of material layers, patterning by photolithography and etching to

produce the required shapes.


Mechanical engineering - Micro electro-mechanical systems (MEMS)

1 Micron-scale mechanical components such as springs, gears, fluidic and heat transfer

devices are fabricated from a variety of substrate materials such as silicon, glass

and polymers like SU8. Examples of MEMS components are the accelerometers that are used as car airbag sensors, modern

cell phones, gyroscopes for precise positioning and microfluidic devices used

in biomedical applications.


Microphone - MEMS microphone

1 Major manufacturers producing MEMS silicon microphones are

Wolfson Microelectronics (WM7xxx), Analog Devices, Akustica (AKU200x), Infineon (SMM310 product), Knowles Electronics, Memstech (MSMx), NXP Semiconductors, Sonion MEMS, AAC Acoustic Technologies, and Omron.


Frequency multiplier - Microelectromechanical (MEMS) frequency doubler

1 The inherent square-law nonlinearity of the voltage-to-force transfer function of a cantilever resonator’s capacitive transducer can be employed for the

realization of frequency doubling effect.[http://arxiv.org/abs/1210.3491

Microelectromechanical system cantilever-based frequency doublers] Due to the low-loss attribute (or

equivalently, a high Q) offered by MEMS devices, improved circuit performance can be expected from a

micromechanical frequency doubler than semiconductor devices utilized for the same

task.[http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=arnumber=1386679isnumber=30188 1.156-GHz

self-aligned vibrating micromechanical disk resonator]


MEMS

1 'Microelectromechanical systems' ('MEMS') (also written as micro-electro-mechanical, MicroElectroMechanical or

microelectronic and microelectromechanical systems) is the technology of very small devices; it merges at the nano-scale into

nanoelectromechanical systems (NEMS) and nanotechnology. MEMS are also referred to

as Micromachinery|micromachines (in Japan), or micro systems technology – MST

(in Europe).https://store.theartofservice.com/itil-2011-foundation-complete-certification-kit-fourth-edition-study-guide-ebook-and-online-course.html

MEMS

1 Because of the large surface area to volume ratio of MEMS, surface

effects such as electrostatics and wetting dominate over volume

effects such as inertia or thermal mass.


MEMS

1 An early example of a MEMS device is the resonistor – an

electromechanical monolithic resonator.Electromechanical

monolithic resonator, [http://www.google.com/patents/abou

t?id=hpcBAAAAEBAJdq=ELECTROMECHANICAL+MONOLITHIC+RESONATOR US patent 3614677], Filed April 29,

1966; Issued October 1971https://store.theartofservice.com/itil-2011-foundation-complete-certification-kit-fourth-edition-study-guide-ebook-and-online-course.html

MEMS - Silicon

1 Silicon is the material used to create most integrated circuits used in

consumer electronics in the modern industry. The economies of scale, ready availability of cheap high-quality materials and ability to

incorporate electronic functionality make silicon attractive for a wide

variety of MEMS applications.


MEMS - Silicon

1 Silicon also has significant advantages engendered through its material properties


MEMS - Polymers

1 MEMS devices can be made from polymers by processes such as injection molding, Embossing (manufacturing)|embossing or

stereolithography and are especially well suited to microfluidic

applications such as disposable blood testing cartridges.


MEMS - Metals

1 Metals can also be used to create MEMS elements. While metals do not have some of the advantages displayed by silicon in

terms of mechanical properties, when used within their limitations, metals can exhibit very high degrees of reliability. Metals can

be deposited by electroplating, evaporation, and sputtering processes. Commonly used

metals include gold, nickel, aluminium, copper, chromium, titanium, tungsten,

platinum, and silver.https://store.theartofservice.com/itil-2011-foundation-complete-certification-kit-fourth-edition-study-guide-ebook-and-online-course.html

MEMS - Ceramics

1 titanium nitride|TiN, on the other hand, exhibits a high electrical conductivity and large elastic modulus allowing to realize

electrostatic MEMS actuation schemes with ultrathin membranes


MEMS - Deposition processes

1 One of the basic building blocks in MEMS processing is the ability to

deposit thin films of material with a thickness anywhere between a few

nanometres to about 100 micrometres. There are two types of

deposition processes, as follows.


MEMS - Physical deposition

1 Physical vapor deposition (PVD) consists of a process in which a

material is removed from a target, and deposited on a surface


MEMS - Chemical deposition

1 Chemical deposition techniques include chemical vapor deposition (CVD), in

which a stream of source gas reacts on the substrate to grow the material

desired. This can be further divided into categories depending on the details of

the technique, for example, LPCVD (Low Pressure chemical vapor deposition) and

PECVD (Plasma Enhanced chemical vapor deposition).


MEMS - Chemical deposition

1 Oxide films can also be grown by the technique of thermal oxidation, in

which the (typically silicon) wafer is exposed to oxygen and/or steam, to grow a thin surface layer of silicon

dioxide.


MEMS - Lithography

1 Lithography in MEMS context is typically the transfer of a pattern into

a photosensitive material by selective exposure to a radiation

source such as light


MEMS - Lithography

1 This exposed region can then be removed or treated providing a mask

for the underlying substrate. Photolithography is typically used

with metal or other thin film deposition, wet and dry etching.


MEMS - Photolithography

1 Photolithography is the process of transferring geometric shapes on a

mask to the surface of a silicon wafer. The steps involved in the

photolithographic process are wafer cleaning; barrier layer formation;

photoresist application; soft baking; mask alignment; exposure and development; and hard-baking.



1 In the first step, the wafers are chemically cleaned to remove

particulate matter on the surface as well as any traces of organic, ionic,

and metallic impurities



1 There are two types of photoresist: positive and

negative



1 Negative resists behave in just the opposite manner


MEMS - Electron beam lithography

1 Electron beam lithography (often abbreviated as e-beam lithography) is the practice of scanning a beam of

electrons in a patterned fashion across a surface covered with a film

(called the resist), (exposing the resist) and of selectively removing

either exposed or non-exposed regions of the resist (developing)



1 The primary advantage of electron beam lithography is that it is one of the ways to beat the diffraction limit

of light and make features in the nanometer regime. This form of

maskless lithography has found wide usage in photomask-making used in

photolithography, low-volume production of semiconductor components, and research

development.https://store.theartofservice.com/itil-2011-foundation-complete-certification-kit-fourth-edition-study-guide-ebook-and-online-course.html


1 The key limitation of electron beam lithography is throughput, i.e., the very long time it takes to expose an entire silicon wafer or glass substrate. A long

exposure time leaves the user vulnerable to beam drift or instability which may

occur during the exposure. Also, the turn-around time for reworking or re-design is lengthened unnecessarily if the pattern is

not being changed the second time.


MEMS - Ion beam lithography

1 It is known that focused-ion-beam lithography has the capability of writing



1 extremely fine lines (less than 50nm line and space has been achieved) without

proximity



1 effect. However, because the writing field in ion-beam

lithography is quite small, large area patterns must be created by stitching together the small fields.


MEMS - Ion track technology

1 Ion track technology is a deep cutting tool with a resolution limit

around 8nm applicable to radiation resistant minerals, glasses and

polymers


MEMS - X-ray lithography

1 X-ray lithography, is a process used in electronic industry to selectively

remove parts of a thin film. It uses X-rays to transfer a geometric pattern

from a mask to a light-sensitive chemical photoresist, or simply

resist, on the substrate. A series of chemical treatments then engraves

the produced pattern into the material underneath the photoresist.


MEMS - Etching processes

1 In the former, the material is dissolved when immersed in a chemical solution.


MEMS - Etching processes

1 In the latter, the material is sputtered or dissolved using reactive ions or a vapor phase etchant. for a somewhat dated overview of MEMS

etching technologies.


MEMS - Wet etching

1 Wet chemical etching consists in selective removal of material by

dipping a substrate into a solution that dissolves it. The chemical nature

of this etching process provides a good selectivity, which means the

etching rate of the target material is considerably higher than the mask

material if selected carefully.


MEMS - Isotropic etching

1 Etching progresses at the same speed in all directions. Long and

narrow holes in a mask will produce v-shaped grooves in the silicon. The

surface of these grooves can be atomically smooth if the etch is

carried out correctly, with dimensions and angles being extremely

accurate.


MEMS - Anisotropic etching

1 Some single crystal materials, such as silicon, will have different etching

rates depending on the crystallographic orientation of the

substrate


MEMS - HF etching

1 Hydrofluoric acid is commonly used as an aqueous etchant for silicon

dioxide (, also known as BOX for SOI), usually in 49% concentrated form,

5:1, 10:1 or 20:1 BOE (buffered oxide etchant) or BHF (Buffered HF). They were first used in medieval times for

glass etching. It was used in IC fabrication for patterning the gate oxide until the process step was

replaced by RIE.https://store.theartofservice.com/itil-2011-foundation-complete-certification-kit-fourth-edition-study-guide-ebook-and-online-course.html

MEMS - HF etching

1 Hydrofluoric acid is considered one of the more dangerous acids in the cleanroom. It penetrates the skin

upon contact and it diffuses straight to the bone. Therefore the damage is

not felt until it is too late.


MEMS - Electrochemical etching

1 Electrochemical etching (ECE) for dopant-selective removal of silicon is a common method to automate and

to selectively control etching


MEMS - Xenon difluoride etching

1 Xenon difluoride () is a dry vapor phase isotropic etch for silicon

originally applied for MEMS in 1995 at University of California, Los

Angeles


MEMS - Reactive ion etching (RIE)

1 In reactive ion etching (RIE), the substrate is placed inside a reactor, and several gases are introduced



1 Deep RIE (DRIE) is a special subclass of RIE

that is growing in popularity



1 The creates a polymer on the surface of the substrate, and the second gas composition ( and )

etches the substrate


MEMS - Die preparation

1 After preparing a large number of MEMS devices on a wafer (electronics)|silicon wafer, individual die (integrated circuit)|dies have to be separated, which is called die preparation

in semiconductor technology. For some applications, the separation is preceded by wafer backgrinding in order to reduce the wafer thickness. Wafer dicing may then be performed either by sawing using a cooling

liquid or a dry laser process called wafer_dicing#Stealth_dicing|stealth dicing.


MEMS - Bulk micromachining

1 Bulk micromachining is the oldest paradigm of silicon

based MEMS


MEMS - Surface micromachining

1 Analog Devices have pioneered the industrialization of surface

micromachining and have realized the co-integration of MEMS and

integrated circuits.


MEMS - High aspect ratio (HAR) silicon micromachining

1 Bonding a second wafer by glass frit bonding, anodic bonding or alloy

bonding is used to protect the MEMS structures


MEMS - Applications

1 In one viewpoint MEMS application is categorized by

type of use.


MEMS - Applications

1 In another view point MEMS applications are categorized by the

field of application (commercial applications include):


MEMS - Applications

1 *Inkjet printers, which use piezoelectrics or thermal bubble ejection to deposit ink on

paper.


MEMS - Applications

1 *Accelerometers in modern cars for a large number of purposes including

airbag deployment in collisions.


MEMS - Applications

1 [ http://www.eetimes.com/showArticle.j

html?articleID=200900669 There's more to MEMS than meets the

iPhone], EE Times, (2007-07-09) and a number of Digital Cameras (various

Canon Digital IXUS models)


MEMS - Applications

1 *MEMS gyroscopes used in modern cars and other applications to detect

yaw, pitch, and roll|yaw; e.g., to deploy a roll over bar or trigger

dynamic stability control


MEMS - Applications

1 *Silicon pressure sensors e.g., car tire pressure sensors, and disposable blood

pressure sensors


MEMS - Applications

1 *Display device|Displays e.g., the Digital micromirror device|DMD chip in a projector based on Digital Light Processing|DLP technology, which has a surface with several hundred

thousand micromirrors or single micro-scanning-mirrors also called

microscanners


MEMS - Applications

1 *Optical switching technology, which is used for switching technology and alignment for data communications


MEMS - Applications

1 *Bio-MEMS applications in medical and health related technologies from Lab-On-Chip to

MicroTotalAnalysis (biosensor, chemosensor), or embedded in medical devices e.g. stents.

[ http://ves.sagepub.com/content/46/8/605 Microelectromechanical Systems and

Nanotechnology. A Platform for the Next Stent Technological Era ,Louizos-Alexandros Louizos,

Panagiotis G. Athanasopoulos, Kevin Varty,VASC ENDOVASCULAR SURG November 2012 vol. 46

no. 8 605-609, doi: 10.1177/1538574412462637]


MEMS - Applications

1 *Interferometric modulator display (IMOD) applications in consumer electronics (primarily displays for mobile devices), used to create interferometric modulation −

reflective display technology as found in mirasol displays


MEMS - Applications

1 *electrostatic fluid accelerator|Fluid acceleration such as for micro-cooling


MEMS - Applications

1 *Micro-scale Energy harvesting including piezoelectric, electrostatic

and electromagentic micro harvesters.


MEMS - Applications

1 *Micromachined Ultrasound Transducer including Piezoelectric

Micromachined Ultrasonic Transducers and Capacitive Micromachined Ultrasonic

Transducers.


MEMS - Applications

1 Companies with strong MEMS programs come in many sizes. The larger firms specialize in

manufacturing high volume inexpensive components or packaged solutions for end markets such as automobiles, biomedical,

and electronics. The successful small firms provide value in innovative solutions and absorb the expense of custom fabrication with high sales margins. In addition, both large and small companies work in RD to

explore MEMS technology.


MEMS - Industry structure

1 The global market for micro-electromechanical systems, which includes products such as

automobile airbag systems, display systems and inkjet cartridges totaled $40 billion in 2006

according to Global MEMS/Microsystems Markets and Opportunities, a research report from SEMI and Yole Developpement and is forecasted to

reach $72 billion by 2011.[http://www.azonano.com/news.asp?

newsID=4479 Worldwide MEMS Systems Market Forecasted to Reach $72 Billion by 2011]


MEMS - Industry structure

1 While MEMS manufacturing continues to be dominated by used

semiconductor equipment, there is a migration to 200mm lines and select

new tools, including etch and bonding for certain MEMS

applications.


Wavelength selective switching - Microelectromechanical Mirrors (MEMS)

1 The incoming light is broken into a spectrum by a diffraction grating

(shown at RHS of Figure) and each wavelength channel then focuses on

a separate MEMS mirror



1 This technology has the advantage of a single steering surface, not

necessarily requiring polarization diversity optics. It works well in the

presence of a continuous signal, allowing the mirror tracking circuits to dither the mirror and maximise

coupling.



1 MEMS based WSS typically produce good extinction ratios, but poor open loop performance for setting a given

attenuation level


Wavelength selective switching - MEMS Arrays

1 In this case, the angle of the MEMs mirrors is changed to

deflect the beam


MEMS magnetometer - Introduction

1 Magnetic field sensors|Magnetic field sensing can be categorized into four general typesLenz, J., Edelstein, A.S.,

Magnetic sensors and their applications


MEMS magnetometer - Introduction

1 Integration of MEMS sensor and microelectronics can further reduce the size of the entire magnetic field

sensing system.


MEMS magnetometer - Lorentz-force-based MEMS sensor

1 This type sensor relies on the mechanical motion of the MEMS

structure due to the Lorentz force acting on the current-carrying

conductor in the magnetic field


MEMS magnetometer - Voltage sensing

1 Beroulle et al.Beroulle, V.; Bertrand, Y.; Latorre, L.; Nouet,

P



1 Herrera-May et al.Herrera-May, A.L.; García-Ramírez, P.J.; Aguilera-Cortés, L.A.; Martínez-Castillo, J.; Sauceda-Carvajal, A.; García-González, L.;

Figueras-Costa, E



1 Kádár et al.Kádár, Z.; Bossche, A.; Sarro, P.M.;

Mollinger, J.R



1 Emmerich et al.Emmerich, H.; Schöfthaler, M. Magnetic field

measurements with a novel surface micromachined magnetic-field sensor. IEEE Tans. Electron Dev.

2000, 47, 972-977. fabricated the variable capacitor array on a single silicon substrate with comb-figure

structure. The reported sensitivity is 820 Vrms/T with a resolution 200 nT

at the pressure level of 1mbar.https://store.theartofservice.com/itil-2011-foundation-complete-certification-kit-fourth-edition-study-guide-ebook-and-online-course.html

MEMS magnetometer - Frequency shift sensing

1 Another type of Lorentz force based MEMS magnetic field sensor utilize the shift of mechanical resonance

due to the Lorentz force applying to certain mechanical structures.



1 Sunier et al.Sunier, R.; Vancura, T.; Li, Y.; Kay-Uwe, K.; Baltes, H.; Brand, O



1 Bahreyni et al.Bahreyni, B.;

Shafai, C


MEMS magnetometer - Optical sensing

1 The optical sensing is to directly measure the mechanical

displacement of the MEMS structure to find the external magnetic field.



1 Zanetti et al.Zanetti, L.J.; Potemra, T.A.; Oursler, D.A.; Lohr, D.A.; Anderson, B.J.; Givens, R.B.;

Wickenden, D.K.; Osiander, R.; Kistenmacher, T.J.; Jenkins, R.E



1 Keplinger et al.Keplinger, F.; Kvasnica, S.; Hauser, H.;

Grössinger, R


MEMS magnetometer -

1 When the temperature increases, the Young’s modulus of the material used

to fabricate the moving structure decreases


IBM Monochrome Display Adapter - Clone boardshttp://www.vgamuseum.info/index.php/component/content/arti

cle/59-vlasks-articles/index.php?optioncom_custompropertiesviewshowtaskshowcp_madecp_buscp_memsizecp_yearcp_memorycp_familycp_cardtypemdacp_ownercp_directxcp_openglcp_pipelinescp_manufacturercp_processcp_text_search

1 Other boards offered MDA compatibility, although with

differences on how attributes are displayed or the font used.


IBM Monochrome Display Adapter - Clone boardshttp://www.vgamuseum.info/index.php/component/content/arti

cle/59-vlasks-articles/index.php?optioncom_custompropertiesviewshowtaskshowcp_madecp_buscp_memsizecp_yearcp_memorycp_familycp_cardtypemdacp_ownercp_directxcp_openglcp_pipelinescp_manufacturercp_processcp_text_search

1 *United Microelectronics

Corporation UM6845


Hercules Graphics Card - Clone boards[http://www.vgamuseum.info/index.php/component/content/art

icle/59-vlasks-articles/index.php?optioncom_custompropertiesviewshowtaskshowcp_madecp_buscp_memsizecp_yearcp_memorycp_familycp_cardtypeherculescp_ownercp_directxcp_openglcp_pipelinescp_manufacturercp_processcp_text_sear

ch VGA Legacy]

1 Other boards offered Hercules

compatibility.


Hercules Graphics Card - Clone boards[http://www.vgamuseum.info/index.php/component/content/art

icle/59-vlasks-articles/index.php?optioncom_custompropertiesviewshowtaskshowcp_madecp_buscp_memsizecp_yearcp_memorycp_familycp_cardtypeherculescp_ownercp_directxcp_openglcp_pipelinescp_manufacturercp_processcp_text_sear

ch VGA Legacy]

1 *ATi Small Wonder Graphics Solution, 18700, Graphics

Solution Plus


Barometric - Mems Barometers

1 Microelectromechanical systems (or Mems) barometers are extremely small devices between 1 to 100 micrometres in size (i.e. 0.001 to

0.1mm). They are created via lithography or etching. Typical

applications include miniaturized weather stations, electronic barometers and altimeters.


COMSOL Multiphysics - MEMS Module

1 For coupled physical processes in microelectromechanical systems and piezoelectric devices. Incorporates specific multiphysics couplings for

applications such as thin-film damping, piezoelectricity, and fluid-structure interaction. A specialized user interface for electromechanics interactions is included that allows

for MEMS cantilever beam simulations.


List of Freescale products - MEMS Sensors

1 * MMA Series (Multi-G/ Multi-Axis

Accelerometers)


Jaypee Institute of Information Technology - MEMS Design Centre

1 The Centre has undertaken in-house development of Quartz Micro-balance

for Bio-sensors, MEMS Inductor Design for RF wireless application, Microcantilever for communication filter and lead free piezo ceramics

through master level projects.


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