Icepak高级培训教材

AdvancedThermalModelingIcepak高级建模Fluent.incCourseOutline1.Introduction简介2.PrintedCircuitBoards(PCB板)3.ICPackages(IC封装)4.HeatSinks散热器5.InterfaceResistance接触热阻6.Fans,ImpellersandBlowers风扇，叶轮，离心风机7.AltitudeEffects高度的影响8.FlowResistances气流阻尼9.Radiation幅射10.HeatPipes热管11.JouleHeating电阻发热12.ThermoelectricCoolers热电冷却CourseOutline13.ColdPlates冷板14.Transformers变压器15.FlowBaffles气流挡板16.WallEffects壁的效果17.ExternalCoolers/Heaters外部冷却器/加热器Exercises:练习：1.PBGAModelPBGA模型2.SelectingaHeatSink选择散热器3.ModelingTEC热电冷却器模型4.SelectingaBaffle选择挡板5.ModelingExternalCoolers外部冷却器建模Introduction简介TheCaseforThermalManagement•Theheatgeneratedinanelectroniccircuitisinverselyproportionaltotheefficiencyofthecircuit电子线路板产生的热与它的效率成反比•Thepowerthatisnotconvertedtoperformusefulelectromagneticworkislostintheformofheattothesurroundings没有转换成电磁功率的热耗散到了周围的环境•Thepowerwastedasheatincludes:热耗包括–Jouleheating(I2R)loss电阻损失–Powersupply电能提供•Thereliabilityofasemiconductordeviceisdirectlyaffectedbyitsoperatingtemperature工作环境的温度直接影响到半导体设备的可靠性TheCaseforThermalManagement•Virtuallyallelectronicfailuremechanismsareenhancedbytheincreaseinpackagetemperature:实际上，所有电子失效的机理都是由于封装温度升高引起的–StressesduetoTCE(=TotalCompositeError总综合误差）mismatch不匹配–Corrosion腐蚀–Electro-migration电子移动–Oxidebreakdown氧化物崩溃–Currentleakage(whichdoubleswithevery10cinactivedevices)电流泄漏–Degradationinelectricalperformance(duetochangeindeviceparameters)电性能下降TheCaseforThermalManagement•Therateoffailureofelectronicpackagesisdirectlyproportionaltoheatandincreasesexponentiallywiththemaximumtemperatureofthepackage电子封装失效的比例直接与热成正比，而且与封装的最高温度成指数增长•Therateoffailurecanbeexpressedas:失效的比例可描述为：F=Ae-E/KTwhere,F=failurerate,失效率A=constant常数E=activationenergyinelectronvolts(eV)激活的电能K=Boltzmann’sconstant(8.63e-5eV/K),andT=junctiontemperatureinKTheCaseforThermalManagement102002039030730401310502280603860IncreaseinFailureRatewithTemperature(fromabasetemperatureof50C)050010001500200025001020304050TemperatureRise,CIncreaseinFailure,%TheCaseforThermalManagementComponentTemperature=25CTemperature=75CThickfilmresistor515Chipcapacitor1025Powertransistor50300Diode19LogicICs-SSI1251125LogicICs-MSI2502250LogicICs-LSI5004500Source:C.A.Harper,HandbookofThickFilmHybridMicroelectronicsTheEffectofPackageTemperatureonFailure(Numberoffailuresafter1000hrofoperationpermillionunits)每百万个元件工作1000hr失效的数目TheCaseforThermalManagementTemperatureVibrationHumidityDustMajorCausesofElectronicFailure电子失效的主要原因Source:U.S.AirforceAvionicsIntegrityProgram(Reynell,M.,1990)ICPackageTrends•Packagesaregettingthinner封装变薄•Numberofleadsisgettinglargerleads数目增多•Packagefootprintdecreasingtoapproachchipsize为满足chip的尺寸，封装的footprint降低•Packagepinpitchisdecreasing封装的pinpitch减少•Clockspeedisincreasing时钟速度提高•ICchipsareperformingmorecomplextasksICchips功能更复杂–Movingtowardssystem-on-chiptechnology•Packagesaredissipatingmorepower功耗增加•Operatingjunctiontemperatureremainsfixed工作的温度保持不变–55Cforcommodityandhandhelddevices生活用品55C–125Cforautomotivesystems汽车系统125C•Budgetperwattofheatremovalisdecreasing每watt的预算减少PackagingTrendsMarketApplicationYear1998-2000Year2001-2003Year2004-2006Commodity111Hand-Held222Cost/Performance182228HighPerformance100120140HarshEnvironment333Source:SandiaNationalLaboratoriesPackagePowerProjectionTrends(Watts)封装功耗的发展趋势Commodity:Lowcost($300)consumerproductsHand-Held:Batterypowered($1000)productssuchascellular,etc.Cost/Performance:Maximumperformancewithcostlimit($300)(Notebooks,etc.)HighPerformance:Performanceistheprimarydriver(Servers,Avionics,etc.)HarshEnvironment:Automotive,Military,etc.CoolingMethods•Typesofcoolingmethods:散热方法种类：–Naturalconvectionaircooling自然对流–Forcedaircooling强迫对流–Immersionliquidcooling浸润冷却–Boiling蒸发冷却–Heatpipes热管–Coldplates冷板–Thermoelectriccoolers热电冷却–Microchannelcooling微通道冷却–Microjet微喷射冷却•Naturalconvectionaircoolingisusedforlowpowerapplications自然对流散热主要用于低功耗–ItisthesimplestandcheapestcoolingmethodavailableCoolingMethods•Forcedaircooling（强迫对流）isusedforrelativelylargeloadsofheat主要用于相对大的热耗–Itrequiresafan,blower,etc.tomovetheair•ImmersioncoolingisusedtoremovelargeloadsofheatbyimmersingthecomponentsinsideinertdielectricfluidsuchasfluorocarbonorFreon浸润主要用于大热耗，通过将元件浸润到惰性非导热流体中，如碳氟化合物或氟利昂–Typicalapplicationsincludemainframecomputers,supercomputers,high-powertransmitters,etc.•Boilingheattransfer（蒸发换热）istheabsorptionofheatbyaboilingfluidandisusedforhighpowerapplications•Acoldplate（冷板）isablockofmetal,liquid-cooledbyforcedconvection,onwhichcircuitcardsorcomponentsaremounted–Theyareusedinmilitaryandhigh-powerelectronicapplications主要是军用和高功耗电子设备CoolingMethods•MicrochannelCooling（微通道冷却）isatechnologydealingwithverysmallfinsthatareplacedextremelyclosetotheheatdissipatingelement–thecoolantcanbeliquidorgas•Thermoelctriccoolers（热电冷却）aresolidstateheatpumpsthatdonothaveanymovingpartsnoranyworkingfluid–TheymoveheatfromonelocationtoanotherthroughthePeltiereffect•Heatpipes（热管）aredevicesthatprovideapassivemethodoftransferringheatfromoneareatoanother–HeatisabsorbedatoneendthroughevaporationandisrejectedbycondensationattheoppositeendCoolingRoadmap0.651CoolingTechnologyRoad