MICRO ELECTRO MECHANICAL SYSTEMS FOR CRACK … Meeting... · •• Prototyping Prototyping ofof MEMSMEMS crackmetercrackmeter andand earlyearly teststests 2. IMM Bologna S3T Workshop,

S3T Workshop, Porto, 6th-9th Apr. 2010IMM Bologna

MICROMICRO‐‐ELECTROELECTRO‐‐MECHANICAL SYSTEMS FOR CRACK MECHANICAL SYSTEMS FOR CRACK

MONITORING IN AGEING INFRASTRUCTURESMONITORING IN AGEING INFRASTRUCTURESMONITORING IN AGEING INFRASTRUCTURESMONITORING IN AGEING INFRASTRUCTURES

A. RoncagliaA. Roncaglia11, M. Ferri, M. Ferri11, F. Mancarella, F. Mancarella11, J. Yan, J. Yan22, A. A. Seshia, A. A. Seshia22, K. , K. SogaSoga22, J. Zalesky, J. Zalesky33

1 1 CNR, Institute of Microelectronics and Microsystems (IMM), Bologna, ItalyCNR, Institute of Microelectronics and Microsystems (IMM), Bologna, Italy22 U i it f C b id E i i D t t C b id UKU i it f C b id E i i D t t C b id UK2 2 University of Cambridge, Engineering Department, Cambridge, UKUniversity of Cambridge, Engineering Department, Cambridge, UK

3 3 Technical University in Prague, Faculty of Civil Engineering, Technical University in Prague, Faculty of Civil Engineering, Prague, Czech RepublicPrague, Czech RepublicPrague, Czech RepublicPrague, Czech Republic


OutlineOutline

•• UndergroundUnderground MM33 ProjectProject:: MicroMicro--MonitoringMonitoring andand MeasurementMeasurementUndergroundUnderground MM33 ProjectProject:: MicroMicro MonitoringMonitoring andand MeasurementMeasurementSystemSystem forfor AgeingAgeing UndergroundUnderground InfrastructuresInfrastructures

•• MicroMicro--ElectroElectro--MechanicalMechanical SystemsSystems (MEMS)(MEMS) inin crackcrack monitoringmonitoring

•• MEMSMEMS fabricationfabrication•• MEMSMEMS fabricationfabrication

•• Packaging/AssemblyPackaging/Assemblyg g yg g y

•• PrototypingPrototyping ofof MEMSMEMS crackmetercrackmeter andand earlyearly teststests

2


S3T ProjectS3T Project -- Underground M3Underground M3

ProjectProject:: UndergroundUnderground MM33 “Micro“Micro--measurementmeasurement andand monitoringmonitoring systemsystem

S3T Project S3T Project Underground M3Underground M3

ComputerComputer visionvision WirelessWireless sensorsensor networksnetworksProjectProject:: UndergroundUnderground MM33 MicroMicro--measurementmeasurement andand monitoringmonitoring systemsystemforfor ageingageing UndergroundUnderground Infrastructures”,Infrastructures”, EurocoresEurocores SS33TT FPFP66Start: Oct. 1 2006, End: Apr. 30 2010Start: Oct. 1 2006, End: Apr. 30 2010

CoordinatorCoordinator:: ProfProf.. KenichiKenichi Soga,Soga, UniversityUniversity ofof Cambridge,Cambridge, UKUK

P tP t U i itU i it ff C b idC b id (UK)(UK) CNRCNR I tit tI tit t ffPartnersPartners:: UniversityUniversity ofof CambridgeCambridge (UK),(UK), CNRCNR InstituteInstitute ofofMicroelectronicsMicroelectronics andand MicrosystemsMicrosystems (Italy),(Italy), TechnicalTechnical UniversityUniversity ininPraguePrague (Czech(Czech Republic),Republic), UniversidadUniversidad PolitecnicaPolitecnica dede CatalunyaCatalunya (Spain)(Spain)AdvancedAdvanced simulationsimulation methodsmethods MEMSMEMS sensorssensors

AimAim:: DevelopingDeveloping newnew methodsmethods forfor structuralstructural monitoringmonitoring ofof undergroundundergroundinfrastructuresinfrastructures particularlyparticularly undergroundunderground tunnelstunnelsinfrastructures,infrastructures, particularlyparticularly undergroundunderground tunnelstunnels..

3


Underground M3: distributed sensors in tunnelsUnderground M3: distributed sensors in tunnelsgg

4


Objective: MEMS wireless crackmeterObjective: MEMS wireless crackmeterjj

Wall crack

Possible design of MEMSPossible design of MEMS--based wireless crackmeterbased wireless crackmeter

Wall crackWall anchors PCB (wireless

unit/sensor interface)

Silicon chipSilicon chip

Steel bar

Uniaxial strain sensors

5


Objective: MEMS wireless crackmeterObjective: MEMS wireless crackmeter

Crack movement analysis through uniaxial strain detection on a triangular patternCrack movement analysis through uniaxial strain detection on a triangular pattern

jj

1. Expansion 2. Contraction

3. Sliding (A) 4. Sliding (B)

6


MicroMicro--ElectroElectro--MechanicalMechanical--Systems (MEMS)Systems (MEMS)y ( )y ( )

11stst AntisymmetricAntisymmetric 11stst SymmetricSymmetric

anchorsanchors

suspended beamsuspended beam

11 Antisymmetric Antisymmetric resonance mode resonance mode

11 Symmetric Symmetric resonance mode resonance mode

suspended beamsuspended beam

coupling gapcoupling gap

actuationactuationelectrodeselectrodes

7


MEMSMEMS resonatorsresonators asas strainstrain sensorssensors

db]

50

SS eso ato seso ato s asas st ast a se so sse so sAxialAxial loadload ResonanceResonance frequencyfrequency shiftshift

-60

-50

de S

pect

rum

[d

-60

-50

ude

Spec

trum

[db]

-80

-70

brat

ed A

mpl

itud

No Strain)-80

-70

Cal

ibra

ted

Ampl

itu

No Strain 72 strain

437000 438000

-90

Cal

i

Frequency [Khz]437000 438000

-90

Frequency [Khz]

MEMSMEMS

C1

-C2

SelfSelf--sustainedsustained oscillationoscillation atat resonanceresonance

8StrainStrain--dependentdependent oscillatoroscillator


ElectromechanicalElectromechanical propertiesproperties ofof resonantresonant MEMSMEMSp pp p

C RR LL CCII IIMotionalMotional currentcurrent

Vdc

C RRmm LLmm CCmmII IImm

CCftftIIftft

FeedthroughFeedthrough currentcurrent

ForFor closedclosed looploop operationoperation mustmust bebe IIftft <<<< IImm

ftft

mmeqeq αα2222mmeq eq ffrr VVdc dc εε00 SS22mmeqeq ffrr mmeqeq22mmeqeq ffrr αα22

QQ αα22

qqLLmm==

αα22CCmm==

442 2 ffrr2 2 mmeqeq

eqeqRRmm==

Q Q αα22αα ==

dd22ФФ11

eqeq eqeq

442 2 ffrr2 2 mmeqeq

eqeq rr

442 2 ffrr2 2 mmeqeqαα22Q Q αα22

9


TheThe problemproblem ofof packagingpackagingg gg g

MEMSMEMSBondingBonding wireswires

PackagePackage-50

um [d

b]

-50

[db]

SteelSteel

PackagePackage

80

-70

-60

d A

mpl

itude

Spe

ctr

80

-70

-60

ated

Am

plitu

de S

pect

rum

[

437000 438000

-90

-80

Cal

ibra

ted

Frequency [Khz]437000 438000

-90

-80

Cal

ibra

Frequency [Khz]

ElectricalElectrical connectionsconnections

MEMS resonator in air (800 Torr)MEMS resonator in air (800 Torr) MEMS resonator in vacuum (3 mTorr)MEMS resonator in vacuum (3 mTorr)VacuumVacuum packagingpackaging wouldwould bebe inin principleprinciple thethe bestbest solutionsolution

10


ObjectivesObjectives ofof MEMSMEMS activityactivity withinwithin UndergoundUndergound MM33jj yy gg

D l tD l t ff MEMSMEMS f b i tif b i ti t h lt h l ff l t ll t l tt•• DevelopmentDevelopment ofof aa MEMSMEMS fabricationfabrication technologytechnology forfor laterallateral resonatorsresonatorswithwith couplingcoupling gapsgaps scaledscaled belowbelow 11 µmµm..

•• InvestigationInvestigation ofof bondingbonding techniquestechniques suitedsuited toto fixfix thethe MEMSMEMS chipchip ononsteelsteel withwith efficientefficient strainstrain transfertransfer..

•• DevelopmentDevelopment ofof aa vacuumvacuum packagingpackaging techniquetechnique forfor MEMSMEMS strainstrainsensorssensors bondedbonded onon steelsteel..

•• RealizationRealization andand testtest ofof aa firstfirst prototypeprototype ofof MEMSMEMS--basedbased crackmetercrackmeter..

11


MEMS sensors fabrication: process flowMEMS sensors fabrication: process flowpp

Device layer: Si 15 µmDevice layer: Si 15 µm

1. SOI wafer1. SOI wafer 2. SiO2. SiO22 depositiondeposition 3. SiO3. SiO22 RIE etchingRIE etching

Device layer: Si 15 µmDevice layer: Si 15 µmSiOSiO222 µm2 µm

Handle: Si 500 µm Handle: Si 500 µm

4. Polysilicon deposition4. Polysilicon deposition 5. Oxidation5. Oxidation 6. Oxide RIE etching6. Oxide RIE etching

7. Scribeline etching7. Scribeline etching 8. Device layer etching8. Device layer etching 9. HF vapour release9. HF vapour release

10. Metal deposition10. Metal deposition

12


MEMS fabrication: gap narrowing testsMEMS fabrication: gap narrowing testsg p gg p g

13


MEMSMEMS fabricationfabrication –– combcomb--drivedrive DETFDETF sensorsensorSS ab cat oab cat o co bco b d ed e se sose so

14


MEMSMEMS fabricationfabrication –– parallelparallel plateplate DETFDETF sensorsensorSS ab cat oab cat o pa a epa a e p atep ate se sose so

15


MEMS fabrication: resonators with various geometriesMEMS fabrication: resonators with various geometriesgg

16


MEMS fabrication: openMEMS fabrication: open--loop testingloop testing

OpenOpen--looploop measurementsmeasurements onon parallelparallel--plateplate DETFDETF devicedevice::

MEMS fabrication: openMEMS fabrication: open--loop testingloop testing

Vdc=Vdc=2020V,V, --2525dBm,dBm, SignalSignal peakpeak >> 1515dB,dB, Q>Q>2000020000,, ff00==490490kHzkHz

DevicesDevices withwith highhigh QQ andand lowlow feedthroughfeedthrough withwith groundedgrounded substratesubstrate::

17

DevicesDevices withwith highhigh QQ andand lowlow feedthroughfeedthrough withwith groundedgrounded substratesubstrate::OKOK forfor closedclosed--looploop operationoperation


Assembly: silicon/steel adhesive bondingAssembly: silicon/steel adhesive bonding

Strain sensors:Strain sensors:•• CEACEA--1313--250UN250UN--120 Vishay 120 Vishay

Adhesives: Adhesives: •• MM--Bond200, twoBond200, two--component cyanoacrylatecomponent cyanoacrylate

y gy g

•• 1111--FAFA--0303--120 RS Components 120 RS Components p y yp y y

•• MM--Bond600, twoBond600, two--component epoxycomponent epoxy

Experimental setup (2)Experimental setup (2)

PCommercial strain gauge

Strain Gauge

Adhesive (M-Bond200 /M-Bond600)

Steel bar

Silicon die

Adhesive (M-Bond200 /M-Bond600)

18

Steel bar


Assembly: silicon/steel solder bondingAssembly: silicon/steel solder bonding

Silicon sampleSilicon sample Steel barSteel bar

y gy g

1. Oxide etch1. Oxide etch 1. Oxide etch1. Oxide etch

2. Cu evaporation2. Cu evaporation 2. Sn2. Sn--Pb Pb depositiondeposition

4. Foil strain gauge sticking on silicon sample4. Foil strain gauge sticking on silicon sample

depositiondeposition

33 Pressure and heating (200Pressure and heating (200 °°C)C)

19

3. 3. Pressure and heating (200 Pressure and heating (200 C)C)


Assembly: silicon/steel strain transferAssembly: silicon/steel strain transferyy

300L=40 mm t=4mm

Strain Gauge Position3/4 L

) 300

400

Strain Gauge Position1/4 L

L=41 mm t=2mm

s)

100

200

Stra

in (

s

TheoreticalN11-FA-03-120

200

300

Stra

in (

s

0

100 N11 FA 03 120 CEA-13-250UN-120 CEA-13-250UN-120

on silicon (MBond 600).CEA-13-250UN-120

on silicon (MBond 200).0 10 20 30 40

0

100 TheoreticalCEA-13-250UN-120 CEA-13-250UN-120

on silicon

0 5 10 15 20 250

Inflection (mm)

AdhesiveAdhesive bondingbonding

0 10 20 30 40

Inflection (mm)

SolderSolder bondingbondingAdhesiveAdhesive bondingbonding SolderSolder bondingbonding

StrainStrain transfertransfer aroundaround 7070 %% StrainStrain transfertransfer aboveabove 9090 %%

20


Packaging: vacuum packaging by glass softeningPackaging: vacuum packaging by glass softening

Vacuum packaging techniqueVacuum packaging technique Measured vacuum levelMeasured vacuum level

g g p g g y g gg g p g g y g g

0

PrototypePrototype

10-1

100

Torr)

10-2

10 1

ssur

e (T

10-3

10

Pre

s

0 50 100 150 20010

Time (h)

Best result with glass softening method: 300 mTorrBest result with glass softening method: 300 mTorr

Problems in reliabilitProblems in reliabilit21

Problems in reliabilityProblems in reliability


Packaging: vacuum packaging by solderingPackaging: vacuum packaging by soldering

VacuumVacuum sealingsealing withwith metalmetal soldersolder insteadinstead ofof glassglass softeningsoftening

g g p g g y gg g p g g y g

10-1

10-2(Tor

r)P

ress

ure

450 500 550 600

10-3

Time (h)

ResultsResults:: improvedimproved reliabilityreliability improvedimproved vacuumvacuum levellevel ((4040 mTorr)mTorr)22

ResultsResults:: improvedimproved reliability,reliability, improvedimproved vacuumvacuum levellevel ((4040 mTorr)mTorr)


Prototyping: crackmeter prototype with MEMS in vacuumPrototyping: crackmeter prototype with MEMS in vacuumyp g p ypyp g p yp

23


Prototyping: crackmeter prototype with MEMS in airPrototyping: crackmeter prototype with MEMS in airyp g p ypyp g p yp

MEMSMEMS sensorsensor

PiezoresistivePiezoresistive sensorsensor

24


Testing: crackmeter with MEMS in airTesting: crackmeter with MEMS in air

OpenOpen looploop measurementsmeasurements onon CrackmeterCrackmeter prototypeprototype withwith MUMPSMUMPS roundrounddiskdisk resonatorsresonators inin airair..

gg

TheThe devicedevice showsshows somesome sensitivitysensitivity toto strain,strain, butbut itsits electromechanicalelectromechanicalpropertiesproperties seemseem toto bebe unsuitableunsuitable forfor closedclosed--looploop operationoperation (too(too largelargefeedthroughfeedthrough andand lowlow peak,peak, atat leastleast withwith capacitivecapacitive sensing)sensing)

25


Testing: crackmeter with MEMS in vacuumTesting: crackmeter with MEMS in vacuum

CrackmeterCrackmeter prototypeprototype assembledassembled withwith vacuumvacuum packagingpackaging ofof aa parallelparallel--plateplate DETFDETF devicedevice

gg

plateplate DETFDETF devicedevice

MEMS sensor

Piezoresistive sensorPiezoresistive sensor

26


Testing: crackmeter strain sensitivityTesting: crackmeter strain sensitivity

MeasurementsMeasurements onon UCAMUCAM--CNRCNR parallelparallel--plateplate resonatorresonator withinwithin thethecrackmetercrackmeter withwith appliedapplied strainstrain

g yg y

crackmetercrackmeter withwith appliedapplied strainstrain..

438,5

Hz]

db]

438,0

Strain releasequen

cy [k

H

-60

-50

e S

pect

rum

[d

437,0

437,5Strain release

nanc

e fre

q

Strain loading

-80

-70

ated

Am

plitu

de

Nostrain 16ustrain 41ustrain 72ustrain92ustrain

0 20 40 60 80 100 120436,5R

eson

Strain [s]

436000 437000 438000 439000

-90

Cal

ibra

Frequency [khz]

92ustrain 107ustrain 118ustrain

StrainStrain sensitivitysensitivity ofof roughlyroughly 1010 Hz/Hz/µStrain,µStrain, stablestable resultsresults withwith constantconstantappliedapplied strainstrain reversiblereversible operationoperation StrainStrain appliedapplied inin thethe rangerange 00--100100 µStrainµStrain

Strain [s]

27

appliedapplied strain,strain, reversiblereversible operationoperation.. StrainStrain appliedapplied inin thethe rangerange 00--100100 µStrainµStrain..


ConclusionsConclusions

•• AA technologytechnology forfor thethe fabricationfabrication ofof laterallateral SOISOI MEMSMEMS resonatorsresonators withwith goodgoodfeedthroughfeedthrough immunityimmunity andand QQ upup toto 5050,,000000 inin vacuumvacuum hashas beenbeen developeddeveloped..

•• StrainStrain transfertransfer fromfrom steelsteel toto siliconsilicon hashas beenbeen evaluatedevaluated toto bebe aroundaround 7070 %% withwithadhesiveadhesive bondingbonding andand aboveabove 9090 %% withwith soldersolder bondingbonding..

•• AA crackmetercrackmeter prototypeprototype hashas beenbeen assembledassembled usingusing aa vacuumvacuum--packagedpackaged parallelparallel--plateplateMEMSMEMS resonatorresonator andand testedtested withwith aa measurementmeasurement setupsetup..

•• OpenOpen--looploop testingtesting ofof thethe crackmetercrackmeter waswas successful,successful, withwith resonatorresonator QQ aroundaround 90009000forfor VacVac == 00..0505 VV andand peakpeak heightheight aroundaround 2020 dBdB.. StrainStrain sensitivitysensitivity aroundaround 1010Hz/µStrainHz/µStrain andand measurementmeasurement repeatabilityrepeatability werewere alsoalso demonstrateddemonstrated usingusing thisthisprototypeprototype..

Future developmentsFuture developments

•• ImplementationImplementation ofof closedclosed--looploop oscillationoscillation forfor thethe crackmetercrackmeter withwith vacuumvacuum packagedpackagedMEMSMEMS..

pp

•• OnOn--fieldfield testingtesting ofof thethe crackmetercrackmeter inin PraguePrague UndergroundUnderground..

•• ImplementationImplementation andand testingtesting ofof multimulti--directionaldirectional strainstrain sensingsensing modulemodule onon aa newnewcrackmetercrackmeter prototypeprototype..

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Documents

MICRO ELECTRO MECHANICAL SYSTEMS FOR CRACK … Meeting... · •• Prototyping Prototyping ofof MEMSMEMS crackmetercrackmeter andand earlyearly teststests 2. IMM Bologna S3T Workshop,