chapter_1 mems

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Overview of MEMS and Microsystems

1. MEMS & Microsystems:

What is MEMS?

Abbreviation of MicroElectro Mechanical System.

Contain components of sizes in 1 micrometer (m) to 1 millimeter (mm).

se the litho!raphic an" other microfabrication technolo!ies to create

miniat#rize" sensors$ act#ators$ an" str#ct#res.

%n fabrication processes$ the a""ition$ s#btraction$ mo"ification$ an"

patternin! of materials are typically "one #sin! technies ori!inally

"evelope" for the inte!rate" circ#it (%C$) in"#stry.

Two principal components of MEMS:

A sensin! or act#atin! element an" a si!nal trans"#ction #nit.

MEMS as a microsensor'

Eample' a press#re sensor

* %np#t si!nal' press#re

* Microsensin! element' a silicon "iaphra!m

* +rans"#ction #nit' piezoresistors (for resistance chan!e)$ pl#s a,heatstone bri"!e circ#it

* -#tp#t si!nal' volta!e chan!e

an aneroid pressure sensor:

The basic operating principle is to couple the pressure to-be measured to one

surface of a membrane and to measure its deflection (knowing the pressure-to-

deflection transfer function). (ovacs$ /000)

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MEMS as a microact#ator'

Eample' a micro!ripper

Microsystems:

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A microsystem is an en!ineerin! system that contains MEMS components

that are "esi!ne" to perform specific en!ineerin! f#nctions.

components (Ma"o#$ 1223)' micro sensors$ act#ators$ an" a processin!

#nit.

Eample' an airba! "eployment system

An intellient microsystem:

%ncorporate si!nal processin!an" close"*loop fee"bac4 controlsystemsinto

a microsystem.

!. MEMS & Microsystem "rod#cts:

/.1 Micro!ears

LIGA toothed wheel (Ruprechtet al.$ 1223)

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p.s. 5%6A' come from the 6erman terms 5itho!raphy (5itho!raphie)$ electroformin!

(6alvanoform#n!)$ an" mol"in! (Abform#n!).

/./ Micro mier

7olymer micro mier (7rotron Mi4rotechni4)

/. %n4*8et 7rintin! 9ea"

7rinciples of %n4*8et 7rintin!'

: ;rops are shot o#t from !enerator G.

: ;rops receive a char!e in char!in! #nit C.

: +he electic fiel"E"eflects the motion of the "rop.

: +he "rop lan"s at the position on the paper.


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A thermal*b#bble*act#ate" "roplet !enerator (Allen et al.$ 12>?)'

An improve" "roplet !enerator (+sen! et al.$ 122>)'

Comparison of printing results:

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HP 51626A Printhead Microinjector (Tseng, !!")

/.= Micro*lens

micro*lens (9ec4ele et al.$ 122>)

/.? Micromirrors ()

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(a)

(b)


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silicon to b#il" an entire circ#it) Das pro"#ce" at CA.

* %n 12?>$ the first %C Das pro"#ce" by ac4 ilby at +eas

%nstr#ments.

* +o"ay$ #ltra lar!e scale inte!ration (5S%) can contain 10 million

transistors an" capacitors on a chip.

. Microsystems and Microelectronics

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'. The M#ltidisciplinary (at#re of Microsystem )esin and Man#fact#rin

3 nat#ral science areas are involve"'

%. Electrochemistry ()' e. electroplatin! (F in the

5%6A process)F f#el cell ().

%%. Electrohy"ro"ynamics%%%. Molec#lar biolo!y ()

%G. 7lasma physics ()

G. Scalin! laDs

G%. H#ant#m physics ()

G%%. Molec#lar physics ()' molec#lar "ynamics (

)

p.s.' 1. H#ant#m physics' for eample$ st#"y the movement of electrons in

semicon"#ctor materials.

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/. Electrohy"ro"ynamics involves the "rivin! of an ionize" fl#i" by the

application of electric fiel"s.

? en!ineerin! areas'

%. Mechanical en!ineerin!

%%. Electrical en!ineerin!

%%%. Chemical en!ineerin!

%G. Material en!ineerin!

G. %n"#strial en!ineerin!

*. Microsystems and Miniat#ri+ation

enefits of miniat#rization'

%. +en" to move faster.

%%. Enco#nter feD problems in thermal "istortion an" vibration.

%%%. Ma4e them more s#itable for applications in me"icine an"

s#r!ery an" in microelectronic assemblies.

%G. ;esirable in satellites an" spacecraft en!ineerin!.

G. S#itable for telecomm#nication systems.

Eamples'

* Comp#ters' a"vance" in ?0 years from the vac##m*t#be technolo!y to

the %C technolo!y.smaller size$ b#t better performance.

* io*chips' shorter timefor "isease or vir#s "etection (pl#s m#ch less

samplesreire").

,eference:

1. 9alli"ay$ ;.$ esnic4$ .$ an" ,al4er. .$ $ Electrostatic

comb"rive*act#ate" micromirrors for laser*beam scannin! an" positionin!$

o#rnal of Microelectromechanical Systems$ Gol. 3$ %ss#e 1$ pp. /3 :3.

=. ovacs$ 6eor!e +. A.$ Micromachine" +rans"#cers So#rceboo4$ Ma6raD*9ill

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Companies$ %nc.$ /000.

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