9._14301500_The Art of MEMS+IC Simulation_Semicon Taiwan 2011

8/3/2019 9._14301500_The Art of MEMS+IC Simulation_Semicon Taiwan 2011

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The Art of MEMS+IC Simulation

MEMS+ 2.0: Enabling System-level Design with

Matlab, Simulink and Cadence Virtuoso

The Art of MEMS+IC Simulation

MEMS+ 2.0: Enabling System-level Design with

Matlab, Simulink and Cadence Virtuoso

Angela Chao, PhD / Technical Manager /

www.apic.com.tw

SEMICON Taiwan, September 2011

Angela Chao, PhD / Technical Manager /

www.apic.com.tw

SEMICON Taiwan, September 2011


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MEMSaremicro ornanoscaled

devices

Typically

comprise

a

MEMS

sensingoractuationdeviceand

integratedelectronics

DisconnectbetweenMEMSandIC

designflows

leads

to

long

developmentcyclesandhighcosts

Minimaldesignreuse

Introduction

Digital micro-mirror device (DMD)

by Texas Instruments


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ICandlayoutdesignersrequireaMEMScomponentfortheirICdesign

environment

MEMSProductDesignRequires

Collaboration

ICDesignandSimulationToolsMEMSDesignandSimulationTools


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Howcananaccuratecircuitorsystemmodelbecreatedconsideringthe

complexityofstateoftheartMEMSdevices?

TheCollaborationChallenge

Analog Devices, Inc. All rights reserved


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ReducedOrderModelingyieldsasystemorcircuitmodelstarting witha

classicFEelementmodel:

ReducedOrderModeling

+Flexibleapproach,onlylimitedbywhatcanbe

modeledwithFEA

Nonparametric

Hardtoincludemechanicalnonlinearitiesandcontact

models

Timeconsuming/hardtoautomate

Requiresin

depth

FEA

knowledge


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RequestsleadingMEMSmanufacturers forparametricmodels

EverytimemyMEMSteamchangesthedevicegeometry,theynotonly

have

to

re

extract,

but

also

re

validate

the

model,

which

limits

our

ability

to

quicklycodesignwithourcircuitteam

Itsimportanttogivethecircuitteamafewgeometricparameterstovary

sotheycanoptimizethesystemcharacteristics.

Toimprove

yield

of

the

entire

system,

we

need

the

entire

model

to

be

sensitivetomanufacturingvariationsinthegeometry.

Whyparametricmodelsare

needed


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Circuitsimulatorcompatiblelumpedmodelsofnonelectricalcomponents

suchasplates,beams,electrodesetc:

+ Parametric,enablingyield,parameterandMonteCarlostudies

+ Canhandlemostformsofnonlinearities

Flexibilityand

applicability

depends

on

the

quality

of

the

available

model

writing

skills

orexistingcomponentlibraries

BehavioralModelingApproach

V

kzkz kz kzC

FEFMR


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Ourfirstanswer:CoventorWareArchitect,aschematicbasedapproachtoMEMS+IC/Systemsimulation:

CoventorWareArchitect


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Everyschematicmodelhadarichsetofparametersinordertoenableamaximumofdesignflexibility:

SchematicModel

Parameterization


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Schematiccreationwasoftenperceivedaslaboriousandnonintuitive

Scene3Dbroughtsomerelief

3DModelwithScene3D


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Userswereoftenimpressedbythesimulationspeedbuthadahardtimeto

appreciatethecomplexityofArchitectsimulations

Simulation Speed

More the 10000 time steps in only 7min on a standard laptop!


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soweadded3Dresultvisualization

Theanimationisgreatly

exaggeratedinvertical

direction


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Withcontinuingimprovementstoourcomponentlibrary,ARCHITECT could

handleanincreasingvarietyofdesigns

andArchitectwasnolongerjustaboutMEMS+ICdesign. FullMEMSdevice

designcould

be

done

in

minutes

Architect Examples

DLPMirrorsRingGyros

RFSwitchesResonators

Accelerometer


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Schematicbasedmodelcreationwasstillunnaturalformostmechanical

engineerswhopreferCADtoolsoratleastlayouteditorsfordesigninput

MostICandsystemdesignerspreferMATLABSimulink,Cadence,Mentor

Graphics,Synopsys(ratherthanSABER!)

Ourmostvaluableasset,ourmodellibrary

wastrapped

inside

SABER

Remaining Caveats

> 15 ManYears

Saber -Mast

BehavioralModel Libraryin C++

> 15 Years


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OurNewApproach

MEMS+

FEMDamping

and

Stress

Analysis

AlgorithmLevelDesign

StructuralLevel

Design

and

PCell

Generation

SEMulator3D

ProcessEmulation


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InsertMEMSmodelinschematic3

ParameterizedMEMS

ComponentLibrary

(.lib)

CoventorMEMS+

Assembledesignin3D1

Visualizesimulationsin3D5

CoventorMEMS+

forMatlabSimulink

SFunctionInterface

Simulate4

ImportMEMSModel2

Symbol


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ParameterizedMEMS

ComponentLibrary(.lib)

CoventorMEMS+

Assembledesignin3D1

CoventorMEMS+

forCadenceVirtuoso

Visualizesimulationsin3D6

ImportMEMSModel2

PCell

Netlist

Symbol

CadenceVirtuoso


PlaceMEMS

pCell

in

layout5

Spectre/UltraSimSimulate4


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MEMS+ PDKand3Ddesignentry

3DMEMS+ modelbasedonAnalogDevicesADXL202

designdataavailabletothepublic


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Allfoundryrelevantdataisstoredintwodatabases,whichareeither

providedbyanexternalfoundryorbythetechnologygroupwithinthe

company

FoundryDataPDK


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Materialpropertiescanbedefinedasvalues,variablesoralgebraicequations

VariableAssignment


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TheProcessEditordetailsthesequenceofMEMSfabricationsteps

Itholdslayernames,thicknessesandsidewallangles

ProcessEditor


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EachlayerisassociatedtooneofthematerialsfromtheMaterialDatabase

LayerMaterialSelection


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VariablesdefinedintheMaterialDatabaseorProcessEditorcan beexposed

totheMEMSdesigner

ExposingVariables


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TheMEMSdesignerstartswithablank,3DcanvasontheInnovatortab

Innovator


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ExposedvariablesfromtheProcessEditororMaterialDatabaseare

automaticallyimportedintoInnovator

PDKVariableImport


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MEMSdevicemodelsarecreatedwithalibraryofparametriccomponent

generatorsforsuspensions,plates,combsandelectricalpads

ParametricComponentLibrary


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TheMEMSdesignerpickscomponentsfromthelibrarytoassemblethe

desiredstructure

AddingComponents


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Eachcomponentcanbeassignedtooneormultiplelayersofthe

correspondingprocessfile

LayerAssignment


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Componentparameterscanbedefinedasvalues,variablesoralgebraic

equations

ComponentParameters


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Thecomponenttreehighlightsthecomponentnamesandthehierarchical

structureofthe3Ddeviceschematic

ComponentTree


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Themechanicalconnectortreeandviewingmodehighlightswhich

componentsarelinkedtogether

MechanicalConnectorView


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Theelectricalviewingmodehighlightselectricalconnectivitywithcolorsand

transparencyinthecanvas

ElectricalConnectorView

Only electricallayers are shown

as solid


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3DInnovatordesignscanbeimportedintoMatlabSimulinksmodeleditor

usingtheMEMS+importtool

MatlabSimulinkModelImport


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TheMEMSdevicemodelinMatlabSimulinkfeaturesallparameters that

wereexposedinMEMS+Innovator

ModelParameters


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Thesymbolviewfeaturesallexposedelectrical,mechanicalandcapacitance

ports

ExposedPorts


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Exposedelectricalportsappearasvoltageinputs

Exposedmechanicalportsappearasforce/torqueinputsandposition/angle

variationoutputs

Exposedcapacitanceportsarepureoutputs

Input/OutputPorts

VoltageInputs

ReferenceFrame motionInputs

CapacitanceOutputs

PositionOutputs

ForceInputs


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TheMEMSsystemdesignercompletesthefeedbackorpostprocessing

circuitusingmodelsfromthestandardlibrary

SystemSchematic


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TheMEMSsystemdesignerconfirmsthedeviceperformancerunning

simulationsintheMatlab/Simulinkenvironment

MEMSDeviceSimulation


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AdditionalanalysisareaccessiblefromtheMEMS+menu

AdditionallySupportedAnalysis


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TheDCAnalysisisaconvenientwaytocreateoperatingpointsfortransient

andfrequencyanalysis

DCAnalysis


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TheModalAnalysiscalculatesEigenmodesandEigenfrequenciesofthe

completesystem

ModalAnalysis


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TheACAnalysisperformsfrequencysweepsofthecompletesystem

ACSmallSignalAnalysis


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MEMS+Workflow


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ParameterizedMEMS

ComponentLibrary(.lib)

CoventorMEMS+

Assembledesignin3D1

forCadenceVirtuoso

Visualizesimulations

in

3D6

ImportMEMSModel2

PCell

Netlist

Symbol

CadenceVirtuoso


PlaceMEMSpCellinlayout5

Spectre/UltraSim

Simulate4

DLPMirror


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TexasInstrumentsdigitallightprocessing[DLP]projectionsystemisbuild

aroundadigitalmicromirrordevice(DMD)ontopofaSRAMcell

DesignExample

DLPmirrorwith

memorycell1

DLPmirrorinMEMS+2

Memorycellschematic3

Schematicofthe

combineddeviceand

memorycellmodel

4

Hierarchicalsymbol

of

a

DLP

mirror

with

memorycell

5

l i i


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ThepositionandorientationoftheDLPmirrorispartoftheexposed

variables

CompleteDeviceDesign


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P t i C ll Vi


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TheMEMS+importtoolautomaticallycreatesaparametric layout and

schematicview

ParametricCellViews

Vi t C ll P t


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Thecreatedcellviewsfeaturesallparametersthatwereexposed inMEMS+

VirtuosoCellParameters

MEMS Device Schematic


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TheMEMSdesigneraddssourcestotheexposedelectricalpinsandconfirms

thedeviceperformancerunningDC,ACandtransientsimulations

MEMSDeviceSchematic

MEMS Device Simulation


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SimulationresultscanbeloadedbackintoMEMS+andanimatedin the3D

canvas

MEMSDeviceSimulation

SRAM Memory Cell Design


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TheICdesigner,meanwhile,createsaschematicoftheSRAMmemorycell

underneatheachmirror

SRAMMemoryCellDesign

Bit Line ~Bit Line

Word Line

Bit Line ~Bit Line

Data ~DataData ~Data

Word Line

Cadence Virtuoso schematic of thememory cell

Complete Pixel Cell


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TheCMOSSRAMcellcaninturnbeconnectedtothemirrortoassemblethe

completepixelcell

CompletePixelCell

DLPmirrorwith

memorycell1

DLPmirrorinMEMS+2

Memorycellschematic3

Schematicof

the

combineddeviceand

memorycellmodel

4

Hierarchicalsymbol

ofaDLPmirrorwith

memorycell

5

Mirror Array Schematic


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Thepixelcellisreplicatedtoformanarrayandconnectedtothedriving

electronics

MirrorArraySchematic

Hierarchical symbol of a DLP

mirror with memory cell

Cadence Virtuoso schematic of memory cell

Mirror Array Simulation


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ThecompletemirrorarraycannowbesimulatedwiththeVirtuoso

simulators:Spectre,UltraSimorAPS

MirrorArraySimulation

150s in less then 30min real time!

Visualization in MEMS+ Scene3D

Integration


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MEMS+takesfulladvantageoftheCadenceVirtuosocustomICdesign

environment

Integration

MonteCarlo

andYield

Analysis

Parasitic

Capacitance

Extraction

Combined

DRCSignoff

MEMSIC

Simulation

ParametricMEMS+ Design


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MEMS+

Design Examples

MEMS+MEMS+

Design ExamplesDesign Examples

LamMode Resonator


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Lam ModeResonator

MEMS+ modelbuildwithone4th order

rectangularplate

and

four

beams

LamMode Filter


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BandpassfiltercanbebuildbycombiningmultipleLam resonators:

Lam ModeFilter

Microphone


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Microphonewithperforatedbackplateusingcircularandarcshapedflexible

plateswithpressureloadsandelectrodes

Microphone

(Perforationarenotshownintheimage) ResultsofaModalAnalysiswith

Matlab/Simulink

PZEActuatedMirror


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Mirrorwithcircularpzemembraneactuation:

VerticalMirrordisplacement[um]asa

function

of

voltage

QuadrilateralPlates withPiezo Layer

Rigid Cylinder(Mirror)

DiskGyro


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DiskGyroscopebuildwithpieandarcshapedflexibleplatemodelswithside

andtopelectrodes

y

VerticalBeam

PiePlatesArcPlateswithSide

andTopElectrodes

MEMS+modeshapescomparedtoatraditionalparabolicbrickmesh

1.22MHz 7.53MHz7.53MHz1.23MHz

RingResonator


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MEMS+ringresonatormadewithstraightbeams,arcplatesandside

electrodes

g

Accelerometer

with FeedbackLoop


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MEMS+generatedaccelerometermodelwithSDforcefeedbackloopin

CadenceSpectre:

p

ThetransientsimulationwithSpectre

completed

in

less

then

10

seconds

!

AccelerationInput

PlateDisplacement

ControlSignal

MEMS+

DesignExamples


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MEMS+ buildsonCoventorsparametricmodellibrarywhichhasbeen

provenonrealworlddesigns

Display Devices

RFSwitches

Resonators

Gyros (Angular Rate Sensors)Accelerometers

TheEnd


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9._14301500_The Art of MEMS+IC Simulation_Semicon Taiwan 2011