集成电路ESD防护课件1

集成电路I/O设计授课教师：赵毅强、陈霏2014年秋4~19周，周四下午15:55~17:3026楼B109课程提纲集成电路封装PackagingCMOS电路的ESD保护ESD介绍集成电路的ESD保护ESD保护在高速及RF电路的应用I/OBuffer设计2ESD介绍

ElectrostaticDischarge3摩擦生电When2SurfacesinContactthenSeparateSomeAtomElectronsMoveCausingImbalanceElectroStaticCharge静电起源4OneSurfaceHasPositiveCharge&OneSurfaceHasNegativeChargeElectroStaticCharge静电起源5静电的极性6AirandhumanskinarecapableofcarryingthemostpositivechargeSiliconrubber,teflonandsiliconarecapableofcarryingthemostnegativecharge静电的储存7Insulators,duetotheirveryhighresistance,arecapableofstoringahugeamountofelectrostaticchargeConductors,duetotheirverylowresistance,arenotabletostoreanycharge陶瓷双列直插式外壳带点人体的静电场85,000Volts4,000V3,000V2,000V

ChargesSeekBalanceDischargeisRapidCreatingHeat静电的放电9ElectrostaticDischargeorESDLightning

Zapfromadoor10

Walkingacrossacarpet: 1,500-35,000volts

Walkingoveruntreatedvinylfloor: 250-12,000volts

Vinylenvelopeusedforwork instructions:600-7,000volts

Workeratabench: 700-6,000volts

Unwindingregulartape:

9,000-15,000volts11ESD的大小ButTofeelaDischargeitmustbeabout3,000volts12ESD的人体感知湿度对ESD的改善13ESDThatAPersonCan’tFeelCanEasilyDamageIC

100voltsorlesscandamagecomponents!14IC的ESD损害15SEMICONDUCTORDEVICESENSITIVITIES16DeviceTypeMOSFETVMOSNMOSGaAsFETEPROMCMOSGaAsFETJFET SAWOp-AMPSchottkyDiodesFilmResistorsBipolarResistorsECLSCRSChottkyTTLThresholdSusceptivity(Volts)10-10030-180060-10060-2000100+200-300025-50140-7000150-500190-2500300-2500300-3000300-7000500+500-1000500-2500ExampleofESDDamageOpticalphotoofalargeIntegratedCircuitwhichhasexperiencedESDdamagetothepinnotedbythearrow.17ExampleofESDDamageHighermagnificationphotoofpinnotedbythearrowinthepriorslideThistakenat400timesmagnificationona4"X5"photo.Thedamageisnotedasthe"fuzz"attheendofthearrow.18ExampleofESDDamageOverlyingglassivationhasbeenremovedandthesurfacedecoratedtoshowtheESDdamageat5,000timesmagnificationinthisscanningelectronmicrograph.19RankingofSemiconductorFailureCauses

EOS/ESDisthe#1CauseofSemiconductorFailureSource:SemiconductorReliabilityNews,March1993EOS/ESD59%Electricaltesting3%Oxide/passivationfailure3%Conductorfailure3%Diefracture4%Leadshort/open7%Wirebonds15%Others6%EOS:ElectricalOverstressedESD:ElectrostaticDischarge20EOS和ESD的关系EOSisusuallydividedintothreecategories1.EOSspecific:Inthiscategoryarelativelysmallvoltage(i.e.16V)isappliedtothedeviceforalongperiodoftime(i.e.1-10ms).Inthiscategorythedeliveredpowerislow.2.ESD:Inthiscategoryahighvoltage(i.e.1-15kV)isappliedtothedeviceinashortperiod(i.e.1-100ns).Thedeliveredpowerinthiscategoryislowaswell.3.Lightning:Thiscategoryinvolvesextremehighvoltageandpower.21ESD失效的模式22DAMAGEMODESCatastrophicFailureDevicenolongeroperatesAremostlycaughtin-houseRepresents10%ofESDfailuresIntermittent/WalkingWoundedDeviceisoperational,buterraticandwillcauseadditionalservicecallsMostexpensivestaticproblemRepresents90%ofESDfailuresESD损害的代价23ComponentLevelBoardLevelSystemLevelFieldServiceLevel$5$500$50$5000CostofESDdamageincreasesbyten(10)foldateveryprocesslevelESD的模型24HumanBodyModel(HBM)25Theprotectionlevel2–4kVChargedDeviceModel(CDM)26Theprotectionlevel500~1200VfortheTQFPpackageis750VfortheuBGApackageis1200VElectronicComponentESDSensitivity(ESDS)

HumanBodyModel(HBM)ESDClass1: Damageyoucan’tfeel:ESDClass2: Damageyoumightfeel:ESDClass3: Damageyoucanprobably detectassparkwithyour ownbody:200to1,999Volts2,000to3,999Volts4,000to15,999VoltsESDClass0: Damageyoucan’tfeel:0to199Volts27CDM

vs.HBMHBM: Deliverthelowestpoweroverthelongesttime. Producesthelargestheatdamagetothepart. CDM: Itisveryfastanddeliversthehighestpowertothepart. DamageoccurstypicallyatthecoreoftheICandhardtodetect(verysmall). ICmanufacturerscalculatethatabout90%ofthefailuresfromthefieldaredue toCDMESDevents.28TinyConductivePathsCanEasilyBeDamagedSmallercomponentsmeangreatersensitivitytoESD.Damagetothesecomponentscannotbedetectedbythenakedeye.

IntegratedCircuit29ESD失效的原因Highcurrentdensities:causeshighpowerdissipationinsemiconductordevices.Thelatticetemperatureincreases->thermaldamage.Sihasanegativeresistancerelationshipwithtemperature->evenhigherpowerdissipationinasmallvolume->highertemperatureandthermalrunawayHighelectricfieldintensity:referstothevoltagedevelopedacrossthedielectricandjunctionsCMOSgateoxideisthethinnestdielectric,itisthemostvulnerabledielectrictoESDdamageThisdamageisintheformofoxidebreakdownInsoftbreakdown(WalkingWounded),theperformanceisOK,buttheleakageisincreased

Afterhardbreakdown(Catastrophic),acurrentpathiscreatedfromthegatetothechannelandthetransistorisdestroyed30OxideRupture(Breakdown)Insub-micronCMOS,duetoverythinoxidedielectrics,gateoxidebreakdownisthemostcommonESDfailure31栅极氧化层击穿趋势32JunctionFilamentationandSpiking33Whensiliconmelts,itsresistancedropsbyafactorof30ormoreMetallizationandPolysiliconBurn-outMetalwires(金属连线),

PolyResistor(电阻)mustbemadewideenoughtohandleanESDcurrentpulse34TheBasicsOfESDControlGroundConductorsShieldESDS

Whenstore

ortransport

outsideEPANeutralize

insulators

withionizers35PersonalGroundingWristStrapsandCoilCordsWristStrapsgroundpersonnelatworkstationsHeelGroundersGroundmobilepersonnelinareaswherethereareESDfloorsSmocksSmocksleevesshouldbeincontactwiththeskin,clothingunderneathshouldnotshow36PersonalGroundingAllPersonalGroundingEquipmentShouldbeTestedorMonitoredDailyWristStrapandFootwearTestingStationsESDgroundmonitoring

ConstantImpedanceOHMMetricsandMonroeElectronicsTestandMeasurementProductsCMSeriesESDWorkstationMonitors37WristStrapsGroundConductorsIncludingPeopleFootGrounders38EquipmentGroundingWorkStationsandTablesMusthavestaticdissipativesurfacesconnectedtothebuildinggroundsource.Musthavewriststrapgroundconnections(2recommended),preferablybananajackreceptacles,connectedinparalleltothebldggroundsourceShouldbecleaneddailywithanantistaticcleaner39GroundAllConductorsinESDProtectedAreaDissipativeWorkSurfaces

GroundESDworksurfacevia groundcordtocommonpointgroundtoequipmentgroundConductiveFloorMats

GroundESDfloormatsviagroundcordtoequipmentground40EquipmentGroundingShelvingandCabinetsMustprovideagroundedsurfaceunlessthepartsremainfullyenclosedwithinshielding-typepackagingStorageBinsAllpartsbinsandcontainersmustbestaticdissipativeorantistaticWheneverpractical,sensitivepartsshouldremainintheoriginalcontaineruntilassembled41ShieldESDSensitiveItemsOutsideProtectedAreaFaradayCageClosedMetallizedShieldingBagChargesKeptonOutsideofPackage:Coveredconductivetotebox42ESDSComponentHandlingandStorageTomoveESDSpartsorassembliesinsideanESDcontrolarea,useoneofthefollowing;StaticdissipativecontainersStaticshieldingcontainersConductivecontainersorboardcarriersGroundmovableracksSurfaceMountDevicesSMDBoxes43IonizationManytimes,equipmentorobjects(insulators)areunabletobegroundedinwhichcaseairionizersshouldbeused.WhatisIonization?AirIonizersuseaprocesscalled"neutralization"toremovestaticchargefrominsulatorsthatcannotbegrounded.IonizersproducepositivelyandnegativelychargedionsandfloodsESDareawithIons.Ionsarechargedparticlesthatarepresentintheair,andasoppositesattract,chargeswillbeneutralizedovertime.44Types