igbt的散热设计

南京银茂微电子制造有限公司NanjingSilverMicroElectronics,Ltd.功率模块及装置的热设计南京银茂微电子制造有限公司NanjingSilverMicroElectronics,Ltd.(Source:USAirForceAvionicsIntegrityProgram)MajorCausesofElectronicsFailures55%Temperature20%Vibration6%Dust19%MoistureFigure1:JunctionLifeStatistics(Source:GECResearch)故障率（10万小时）ThepurposeofthermaldesignOverheated-ThePrimaryCauseforFailureinElectronicEquipment南京银茂微电子制造有限公司NanjingSilverMicroElectronics,Ltd.TheutilizationsofthethermalsimulationConceptDesignHardwareHandcalculations/Estimation/simpleCFDCFDTestingTimeProductdevelopmentcycleThethermaldesigner'simpactontheproductscheduleShortdevelopmenttimeMoreandmorecomplicatedproductsLowcostexpectationEtc…南京银茂微电子制造有限公司NanjingSilverMicroElectronics,Ltd.Mainpurposesofthermalanalysis1.Predictionofcomponenttemperatures;2.Designoptimizationforgoodreliability.南京银茂微电子制造有限公司NanjingSilverMicroElectronics,Ltd.ThermalDesignIncluding:Dielevel---ChipComponentlevel---PackageBoardlevel---PCBSystemlevel---ModuleEnvironmentlevel---RelatedtoVent南京银茂微电子制造有限公司NanjingSilverMicroElectronics,Ltd.ComponentslevelBoardlevelEnvironmentlevelThermalsimulationSystemlevel南京银茂微电子制造有限公司NanjingSilverMicroElectronics,Ltd.EnvironmentlevelBoardlevelSystemlevelComponentslevel南京银茂微电子制造有限公司NanjingSilverMicroElectronics,Ltd.MethodsforHeatDissipationCoolingStylesTraditionalNewNaturalConvectionandRadiationForced-airConvectionThermoelectricCoolingSingle-PhaseLiquidCoolingTwo-PhaseLiquidCooling“Synthetic”JetCoolingHeatConductionviaEmbeddedSolidsCategoriesaccordingtoheattransferdevices:•Heatpipe:generaltypeheatpipe,Loopheatpipe,Capillarypumploopheatpipe,pulsating/oscillatingheatpipe,microheatpipeetc.•Microchannelheatexchanger•Refrigerationsystem•Liquidjetcooling南京银茂微电子制造有限公司NanjingSilverMicroElectronics,Ltd.HowtoChooseaProperMethod?Thegraphshowsheatfluxdensityandvolumetricpowerdensityofallofcoolingmethodswhentemperatureincrementis40degC.南京银茂微电子制造有限公司NanjingSilverMicroElectronics,Ltd.ReferenceforChoosingCoolingMethodCoolingTechnologyCoefficientofHeatTransferW/(m2K)SurfaceHeatFluxDensity,W/cm2(TermperatureDifferenceis40degCbetweenheat-transfersurfaceandworkingmedium)Airnaturalconvection6~160.024~0.064Airforcedconvection25~1500.1~0.6Waternaturalconvection230~5800.9~2.3Oilforcedconvection60~50000.24~20Waterforcedconvection3500~1100014~44Waterboiling(evaporatingcooling)Max54000Max1351)Vaporfilmcondensation11000~260002.6~112)1)indicatesthatTermperatureDifferenceis25degCbetweenheat-transfersurfaceandworkingmedium2)representsthatTermperatureDifferenceis1-10degCbetweenheat-transfersurfaceandworkingmedium南京银茂微电子制造有限公司NanjingSilverMicroElectronics,Ltd.ApplicationsofCoolingTechniquesThermoelectriccoolerLiquidcoolingsystemRemoteheatpipeforlaptopLoopheatpipeMicrochannelcoolerMicrochannelheatexchangerusingliquidLiquidjetcoolingHeatconductionviaembeddedsolids“Synthetic”jetcooling南京银茂微电子制造有限公司NanjingSilverMicroElectronics,Ltd.ComparisonofVariousCoolingTechniquesCoolingTechniqueAdvantagesDrawbacksAuxiliaryDeviceRadiationandNaturalConvectionSimplest,reliable,Notsuitableforhighdensityinternalheatextraction,heattransfercapacityislowest.NoneForced-airConvection1.Thesupplyofcoolingairisreadilyavailable;2.Doesnothavefreezing,boilinganddrippingproblems1.Notsuitableathighaltitudeorlowairdensitylocations;2.Acousticnoiseispresent;3.Vibrationarepresent;4.Hotairejectionmaycausesecondaryproblems.FanSingle-PhaseLiquidCoolingHeattransfercapacityishigh.Itdependsonsensibleheat.Theaddedvolulmeneededtohousetheliquidcircuit.Needtheperiodicmaintenance.Heatexchanger,filter,liquidreservoirandpumpTwo-PhaseLiquidCoolingHeattransfercapacityisveryhigh.Itdependsonlatentheat.Needalargevolumetoplacethesystem.Pump,compressor,pipe,heatexchangersetc.ThermoelectricCoolingCompactsize,operatingisconvenient.Heattransfercoefficientislow.COPislessthan1.NoneHeatConductionviaEmbeddedSolidsEasytomanufacture,therelativelysmallvolumeHeattransfercoefficientisnothigh.None南京银茂微电子制造有限公司NanjingSilverMicroElectronics,Ltd.ComparisonofTwo-PhaseCoolingCoolingTechniquesDegreeofMaturityApplicationMeritsDrawbacksCostRemarkHeatpipeMatureArchitecture,Chemicalindustry,Energy,aero-space,Electronicindustry(suchasPC,laptopcomputer,Powerelectronics)Higherheattransferability,Lowertemperaturegradientbetweenthecondensersectionandevaporatorsection,Light,Non-Noise,HighReliability,Nospecialstart-upconditionHeatpipe,self,cannotdissipatetheheatfromtheelectroniccomponentsandrequiresomesimpledevices,likeheatsink,fan.CheapProcessingtechniqueissimple.RefrigerationVeryMatureArchitecture,Chemicalindustry,Energy,Electronicindustry(suchaslarge-scaleelectronicsystems,Infra-reddetectors,Masersetc.)CoolingeffectisverygoodNeedalargespacingforplacingtheentiresystem.Thereismuchnoise.VeryhighProcessingtechniqueissimple.MicrochannelCoolerNovel,non-matureEnergy,aero-space,militaryHeattransfercoefficientisveryhigh,about100MW/m3Knon-mature,reliabilityisnothigh,thistechniqueisinthestateofthereseach.Needadditionaldevicies.VeryhighManufacturingrequirementisveryhigh.LiquidSprayNovel,non-matureEnergy,aero-space,electronicindustryHeatdisspationcapacityishigher,reachinggreaterthan100W/cm2Needotherauxiliarydevices,requirementofdielectricityisveryhigh.Notbesuitableforgeneralelectronicsystem.Justforalocalhotspot.VeryhighManufacturingrequirementisveryhigh.南京银茂微电子制造有限公司NanjingSilverMicroElectronics,Ltd.SurfacetemperaturePressuredropalongthecoolingfins.Thermalsimulation南京银茂微电子制造有限公司NanjingSilverMicroElectronics,Ltd.Velocityprofileshowninaspecifiedcut-planeThermalsimulation(render)南京银茂微电子制造有限公司NanjingSilverMicroElectronics,Ltd.Thermalsimulation(render)Velocityprofileintheunit南京银茂微电子制造有限公司NanjingSilverMicroElectronics,Ltd.南京银茂微电子制造有限公司NanjingSilverMicroElectronics,Ltd.ThermaltestWindtunnel-tobuildaspecifiedairflowvelocityandambienttemperatureWindtunnelschematicdrawing南京银茂微电子制造有限公司NanjingSilverMicroElectronics,Ltd.影响热分析精度的因素1.建模因素a.PCB板建模纯FR4的导热率为0.35W/(m·℃)，纯铜的导热率为388W/(m·℃)，故铜的含量是影响导热的重要因素。铜线的分布往往比较复杂，不可能进行详细的建模。目前热分析软件的普遍做法是：将PCB板作为一种具有各向异性的均一导热率的材料来处理。b.封装模型建模目前只有的器件厂家会提供详细的封装模型，但在板级和系统级的分析中，采用详细模型会使网格数和计算时间急剧增加，所以一律采用简化模型。模型简化的过程，可能会引入较大的误差，而大多数厂家都不会提供封装模型，给热分析带来了一定的难度。南京银茂微电子制造有限公司NanjingSilverMicroElectronics,Ltd.c.新型传导建模的建模目前一些新型的传导冷却技术如热管，其建模比较困难。通常采用一根具有轴向高传导率的杆来建模，但此轴向传导率很难精确得到。热功耗是影响热分析的重要因素。热功耗很难精确获得。在设计晚期，理论上可以通过测量电流电压来计算电功耗，但实际操作起来比较困难。尤其在复杂电路中对电流进行测量。在设计早期，能够通过某些软件，如Pspise或pro/E来仿真电功耗，但电功耗是温度的函数，但目前软件对温度的考虑仍不充分。而且，不是所有的电功耗都能转化为热功耗，这涉及到器件的工作效率问；同时，热功耗也是温度的函数。2.热功耗因素南京银茂微电子制造有限公司NanjingSilverMicroElectronics,Ltd.3.导热因素对于给定的材料，导热率可同通过材料手册查到。但对于工程技术人员来讲，材料的具体成分往往很难获得，导热率很难选准确。比如塑料，其品种繁多，各品种的导热率相差很大，且手册中的数据都是在标准实验室中获得的，通常模拟的环境不能真实的反应工程实际。同时导热率又是温度的函数。4.对流因素a.空气阻尼系数空气通过管道和进出风口时，会产生一定的压降。空气阻尼系数可以通过直接测量，但它不是常数，会随速度的变化而变化，尤其是在速度较低的时候，分析人员往往将它作为常数来处理，这会带来一定的误差。南京银茂微电子制造有限公司NanjingSilverMicroElectronics,Ltd.b.风扇目前几乎所有的商品热分析软件均不能精确的模拟出由吹风引起的湍流和气流压降。5.热辐射因素辐射率（表面黑度）是影响辐射的主要参数。物体的表面氧化层、粗糙度、表面处理、划痕、灰尘、油脂等都会影响辐射率。所以，仅仅根据手册中查得的数据不可能进行精确的分析。而且，发射率本身也是温度的函数。南京银茂微电子制造有限公司NanjingSilverMicroElectronics,Ltd.IGBTModuleSiliconchipSnPb(63/37),SAC(lead-free),Pb29.5Sn5Ag2.5,Sn96.5Ag3.5CopperoraluminumAlNceramic,Si3N4,BeO,etcCu,Cu-Mo,Cu-Tungsten,AlSiC,Cu-CAluminum,Graphite,AlSiCThermalconductivegreaseTjTcThTaRjcRchRhaTj=Ta+P*(Rjc+Rch+Rha)Wirebond南京银茂微电子制造有限公司NanjingSilverMicroElectronics,Ltd.Mainfailuremechanisms:HighmismatchofCTEbetweenaluminumwiresandsiliconchipTotalinterruptionoftheelectricalconnectionfromchiptotheoutputpinsDeterioratesremovalofheatdissipatedwithinthechipIncreaseofthermalresistanceofthedevice结温频繁变化龟裂剥离铝线和硅片热膨胀系数之差产生应力Solderjointdegradation系统起停壳温Tc大幅平稳变化焊锡层应力偏移，焊锡面龟裂龟裂延伸至硅片下方，热阻增加，结温变化增加，功率循环耐量降低与功率循环寿命相同的线剥离PowercycleThermalcycleBondwireslift-off南京银茂微电子制造有限公司NanjingSilverMicroElectronics,Ltd.OnesidedLTJT:powercyclingreliabilitytwentytimeshigherthanstandardmoduleDoubled-sidedLTJT:powercyclingreliabilitytwicehigherthanstandardone-sidedBasedonsinteringofsub-microsilverflakesSilverstripesof1mmwidthand100μmthicknessDouble-sidedone-sidedLTJT(Lowtemperaturejoiningtechnique)南京银茂微电子制造有限公司NanjingSilverMicroElectronics,Ltd.WirebondsforelectricalconnectionsandheatextractionfromthemodulelowersurfaceDouble-sidedcoolingconceptusingpolyimideflexforelectricalconnectionsandheatremovalfromtheuppersurfaceusingaminiatureheatpipeDouble-sidedcoolingofIPEMs(IntegratedPowerElectronicModules)BumpArrayContactModulesSingle-sidedtemperatureprofilesdouble-sidedtemperatureprofilesA15%decreaseinthemaximumtemperaturerise,and28%oftheheatremovedfromtheupperside.Changethesquarearraytohexagonalclose-packedgeometry,toobtainlargercopperviasrunningthroughtheflexFilltheairgapwiththermally–conductivefillermaterialtoimprovethermalresistanceandhelptorelievethermally-inducedmechanicalstressesHeatpipeattachedwithsolderinsteadofclampedgreasedjointstoreducecontactresistanceattheevaporatorandcondenserends.optimization南京银茂微电子制造有限公司NanjingSilverMicroElectronics,Ltd.•Typicallythetopsideofthemoduleisdevotedtoelectricalinterconnectionswhilethebottomsideisdedicatedtoheatmanagement.•heatviapowerterminalsupsidealsoshouldbetakenintoaccount.Andbusbartemperaturealsoislimitedbyreliability,typicalis105degC.Powerterminalsconnectiontothechipsorsubstratemetallizationbysolderjoints(a)orwirebonds(b).abOfferinggoodthermalbehaviorandcanbeadaptedtocarryveryhighcurrentsSuitableformediumpowerapplicationsandshouldbeshortenough南京银茂微电子制造有限公司NanjingSilverMicroElectronics,Ltd.RthSCreducedbyincreasingcontactsurfaceCircularconnectionholeprovidesbettercontactsurfacetothebusbarIHMAIHMBTmaxdroppedfrom110to94degC;.Confirmedbyexperiments.南京银茂微电子制造有限公司NanjingSilverMicroElectronics,Ltd.SFMIGBT(SolderableFrontMetal焊前金属）IR公司推出，1200VAUIRG7CH80K6B-M，适用于电动汽车(EV)、混合动力汽车（HEV)和中功率驱动器中的高电流、高电压汽车逆变器模块。最新一代场截止沟槽技术，大幅降低了传导和开关损耗。焊前金属可实现双面冷却，提高了散热性能，无焊线封装，从而达到了更高的可靠性。DirectFET南京银茂微电子制造有限公司NanjingSilverMicroElectronics,Ltd.•Solid/transienttemperaturefield、thermalimpedancecurve;•Electrical-thermalcoupling;•Thermal-structurecoupling,i.e.,thermalstress、fatiguecalculation;•optimalmaterialscombination,etc.LineartimeProvideamuchbetterpresentationofequilibriumdataThermalresistanceThermalimpedanceLogtimePresentamoredetailedpresentationoftheshortduration,transient,non-equilibriumthermaldata.南京银茂微电子制造有限公司NanjingSilverMicroElectronics,Ltd.TheweaknessofgreaseMigrationDry(volatility)DegradationbyPump-outMessyPowerondurationpercycle:18minutesPoweroffdurationpercycle:10minutesRecordthetemperaturedifferenceatlastsecondofpoweron.Thetemperatureofhtskandheaterrangefrom25c-90cControlboardGreaseagingtest南京银茂微电子制造有限公司NanjingSilverMicroElectronics,Ltd.SimultaneouslymeasurementofthermalresistanceandthermalgreasethicknessInfineontest南京银茂微电子制造有限公司NanjingSilverMicroElectronics,Ltd.•Thankyou!