Ansys-Icepak高级培训教材PPT课件

1,AdvancedThermalModeling,AdvancedThermalModeling,Icepak高级建模,Fluent.inc,2,CourseOutline,1.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,3,CourseOutline,13.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,4,Introduction,Introduction,简介,5,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,6,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,7,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=Boltzmannsconstant(8.63e-5eV/K),andT=junctiontemperatureinK,8,TheCaseforThermalManagement,9,TheCaseforThermalManagement,TheEffectofPackageTemperatureonFailure(Numberoffailuresafter1000hrofoperationpermillionunits)每百万个元件工作1000hr失效的数目,10,TheCaseforThermalManagement,MajorCausesofElectronicFailure电子失效的主要原因,Source:U.S.AirforceAvionicsIntegrityProgram(Reynell,M.,1990),11,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-chiptechnologyPackagesaredissipatingmorepower功耗增加Operatingjunctiontemperatureremainsfixed工作的温度保持不变55Cforcommodityandhandhelddevices生活用品55C125Cforautomotivesystems汽车系统125CBudgetperwattofheatremovalisdecreasing每watt的预算减少,12,PackagingTrends,PackagePowerProjectionTrends(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.,13,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Itisthesimplestandcheapestcoolingmethodavailable,14,CoolingMethods,Forcedaircooling（强迫对流）isusedforrelativelylargeloadsofheat主要用于相对大的热耗Itrequiresafan,blower,etc.tomovetheairImmersioncoolingisusedtoremovelargeloadsofheatbyimmersingthecomponentsinsideinertdielectricfluidsuchasfluorocarbonorFreon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）istheabsorptionofheatbyaboilingfluidandisusedforhighpowerapplicationsAcoldplate（冷板）isablockofmetal,liquid-cooledbyforcedconvection,onwhichcircuitcardsorcomponentsaremountedTheyareusedinmilitaryandhigh-powerelectronicapplications主要是军用和高功耗电子设备,15,CoolingMethods,MicrochannelCooling（微通道冷却）isatechnologydealingwithverysmallfinsthatareplacedextremelyclosetotheheatdissipatingelementthecoolantcanbeliquidorgasThermoelctriccoolers（热电冷却）aresolidstateheatpumpsthatdonothaveanymovingpartsnoranyworkingfluidTheymoveheatfromonelocationtoanotherthroughthePeltiereffectHeatpipes（热管）aredevicesthatprovideapassivemethodoftransferringheatfromoneareatoanotherHeatisabsorbedatoneendthroughevaporationandisrejectedbycondensationattheoppositeend,16,CoolingRoadmap,NaturalConvection,ModerateForcedAir,AdvancedForcedAir,LiquidCooling,17,CoolingRoadmap,AirNaturalConvection+Radiation,ForcedAirConvection,ImmersionNaturalConvectionFluorocarbons,Immersion-BoilingFlorocarbons,WaterForcedConvection,18,ModesofHeatTransfer,Threemodelsofheattransfer:三种传热方式：Conduction传导Convection对流Radiation幅射Conductionisaprocessinwhichheatflowsbetweentwomedia(solid,liquidorgas)thatareindirectcontactwithoneanother传导是发生在两种直接接触的介质（固体，液体，气体）Inconduction,energyistransferredthrough:传导过程中，能量通过以下方式传递Movementoffreeelectron自由电子运动latticevibration点阵振动Convectionisthetransferofthermalenergybetweenasurfaceandamovingfluidhavingsometemperaturedifference对流发生在有温差的表面和运动流体间的传热,19,ModesofHeatTransfer,Convectioncanbe:对流有如下两种方式：Free(natural)convectionForcedconvectionRadiationisthetransferofheatbetweentwosurfacesthathavenodirectcontact:幅射发生在两种没有直接接触的表面Energyisemittedthroughelectromagneticwaves能量通过电磁波传递Allobjectattemperaturesabove0Kemitthermalradiation所有物体大于0K均发生热幅射Mostofthethermalradiationtakesplaceintheinfrared(红外）wavelength(0.1to100micron)几乎所有热幅射发生在红外波长范围Therateofenergytransferdependsonsurfaceconditionsandtheviewbetweentheparticipatingbodies能量传递率与表面条件及相关物体间的视角有关,20,Conduction,FouriersLawofConduction:(1Dconduction)1D传导,21,Conduction,Where,Q=heattransferT=temperatureA=cross-sectionalareak=thermalconductivityoftheslabDX=slabthicknessR=DX/(kA)=ConductionresistanceTheslabisassumedtoconductinonedirection,FouriersLawofConduction:(1Dconduction),22,Conduction,FouriersLawofConduction:(1Dconduction),23,Conduction,FouriersLawofConduction:(1Dconduction),24,Convection,Convectionmaybefreeorforced.对流可以是自然和强迫Infreeconvectiontheflowisinducedbydensitydifferencescausedbytemperaturevariationswithinthefluid.自然对流是由于温度变化引起的流体内部密度不同产生的Inforcedconvectiontheflowisgeneratedbyexternalmeanssuchasfan,blower,pump,wind,etc.强迫对流则是由于外部方式造成的气流Flowsmayalsobeclassifiedasinternalflowsandexternalflows.气流也可以分为内流和外流Aninternalflowisflowthroughconfineddomainsuchasductsorchannels.内流是发生在一定的空间内，如管道等Anexternalflowisflowoversurfaceswhichcanbefullyorpartiallyunconfined.外流是全部或部分不在空间内的气流,25,Convection,Flowsmayalsobeclassifiedas气流可以被分为：laminar,or层流或Turbulent湍流Alaminarflowisahighlyorderedflowwherefluidparticlesmovealongidentifiablepaths层流是很规则的气流，气流的流线轨迹比较一致Inturbulentflowsfluidmotionishighlyirregularandischaracterizedbyrandom,three-dimensionalmotion湍流很不规则，比较任意，三维运动Itinvolvesstrongmixingandmorevigorousheattransferflowisinherentlytime-dependentMostreallifeflowsareturbulentflows大多数流动是湍流Flowsverynearsurfaces(ofobjects)areusuallylaminarflows离开物体表面很近气流通常是层流ThisregioniswellwithintheboundarylayerItiscalledthelaminarsub-layer,26,Convection,ExternalFlow外流,InternalFlow内流,27,Convection,LaminarFlow层流,TurbulentFlow湍流,28,Convection:NewtonsLawofCooling,29,Convection:Typicalhvalues,RepresentativehandRvalues典型的h和R值,30,Convection:FactorsAffectingh,Theheattransfercoefficient,h,dependsonmanyfactors:传热系数取决于很多因素Turbulentflowshavelargerheattransfercoefficientthanlaminarflows湍流比层流h值大Ingeneral,forcedconvectionflowshavehigherheattransfercoefficientthannaturalconvectionflows强迫对流比自然对流h值大Liquidflowshavelargerheattransfercoefficientthangasflows液体比气体h值大Roughsurfaceshavelargerheattransfercoefficientthansmoothsurfaces(duetoflowturbulence)粗糙表面比光滑表面h值大Entry(undeveloped)flowshavelargerheattransfercoefficientthanfullydevelopedflows未展开气流比完全展开气流h值大Unsteadyflowstendtohavehigherheattransfercoefficientthansteadyones非稳态比稳态h值大,31,PrintedCircuitBoards,PCBs,32,PrintedCircuitBoards,Component-side(top)view,Source:Pixeldirect,33,PrintedCircuitBoards,Solder-side(bottom)view,Source:Pixeldirect,34,PrintedCircuitBoards,Aprintedcircuitboard(PCB)isgenerallyamulti-layeredboardmadeofadielectricmaterial(glass-reinforcedpolymerorFR4)andseverallayersofcopperplanesPCB是由FR4和几层铜板构成ItservestowiremountedICchipsthatwouldotherwiseneedthousandsofpoint-to-pointwireconnectionsAsingle-layerboardhascomponentsmountedononesideandcopper(conductor)patternontheother一层板的元件安装在一边，铜线（导热器）在另一边Thecopperpatternisestablishedbyphoto-etchingacopperfoilpastedoverFR4Adouble-layerboardhascopper(conductor)patternaswellascomponentsonbothsides两层板有铜，两边都有元件Amulti-layerboardismadeofseveraldouble-sidedboardswithinsulatinglayersinbetween多层板由几个两层板组成，在层与层之间有绝缘层,35,PrintedCircuitBoards,HeatandpressureisappliedtolaminatethelayersintoarigidstructurecalledthePCB加热和加压而制成一种坚硬的结构叫PCBMulti-layerPCBsgenerallyhave4-10layersofcopper多层PCBs通常有4-10层铜线Toestablishelectricalconnectionbetweenthedifferentcomponentsandthecopperlayers,vias(smallholeslinedwithmetalplates)aredrilledthroughthethicknessofthePCB为了使不同元件和铜线层建立连接，通过在PCB厚度上打孔（vias）TheviasmaycutthroughtheentirethicknessofthePCBorconnectafewlayersonlyVias可能穿透整个板或只连接几层Inamulti-layerboard,someofthecopperlayersareusedtoprovidegroundandpowersupplyvoltages,whiletheremaininglayersareusedtointerconnecttheICchips多层板中，有些铜线层会用来提供基础和电流电压，而其它的层用来提供ICchips间的连接,36,PrintedCircuitBoards,Laminatesinamulti-layerPCB,37,PrintedCircuitBoards,Theareacoverageofthecopperlayerscanvarybetween10%to90%铜线层的含量通常在10%到90%Thethicknessofonelayerofcopperisabout35micronor,asiscommonlyreportedintheindustry,itcontains1ozofcopperpersquarefoot一层铜的厚度约在35微米或每平方英尺含1oz的铜ComponentsmaybemountedonaPCBusing元件可以通过以下方式安装到PCB上Though-HoleTechnology(THT),or穿孔型Surface-MountTechnology(SMT)表面安装型InTHT,thelegs(pins)ofthecomponentspassthroughholesandaresolderedattheoppositesideofthePCBTHT方法，pins通过孔到PCB另一面焊接InSMT,thechipsaresolderedtothePCBandconnectedtotheconductorlayeronthesamesideofthePCBSMT方法，chips被焊接到PCB同一侧,38,PrintedCircuitBoards,TheconductivityofpureFR4is0.25W/mK纯FR4的导热率为0.25Theconductivityofpurecopperis388W/mK铜的导热率为388Fromthermalmodelingpointofview,aPCBbetreatedasahomogeneousmaterialwithnon-isotropic(direction-dependent)conductivity从热模型的角度来看，PCB应作为一种非正交导热率的材料ThePCBmodelmaywillcontainin-planeandnormal-to-planeconductivityvaluesPCB应有面内和法向导热值Thein-planeconductivityismuchlargerthanthenormal-to-planeconductivity面内值要比法向大得多Thein-planeconductivityincreaseswiththenumberofcopperlayersofthePCB面内导热率随着铜线层的增加而增加ThenormalconductivityaPCBisnearlyconstantatabout0.3W/mK法向导热率通常在0.3,39,PrintedCircuitBoards,Thein-planeandnormal-to-planeconductivityvaluesmaybecalculatedasfollows:面内导热率可采用下面公式计算：kin-plane=S(kiti)/(Sti)knormal=Sti/S(ti/ki)ki=fi*kcuwhere,fi=fractionalcoverageofcopperk=conductivityofalayer(W/mK)t=thicknessofalayer(m)Whenhigheraccuracyisdesired,aPCBmaybemodeledusingmultipleplates:如果还希望得到更准确的数值，PCB应采用多层板来建模AconductingthickplatefortheFR4,andseveralconductingthinplatesforthecopperlayers,40,PrintedCircuitBoards,Example例如：Numberofculayers=8Thicknessof1layerofcopper=1oz=3.5e-5mThicknessof1layerofFR4=1.453e-4mConductivityofcopper=388W/mKConductivityofFR4=0.25W/mKIn-planeconductivity:Kp=(8*388*3.5e-5)+(9*0.25*1.453e-4)/1.588e-3=68.6W/mKNormalconductivity:Kn=1.588e-3/(8*3.5e-5/388)+(9*1.453e-4/0.25)=0.303W/mK,41,PrintedCircuitBoards,42,PCBModeling,APCBmaybemodeledusingoneoftwoways:PCB可以采用如下的两种方法建模：DetailedmodelCompactmodelTheDetailedPCBModelincludes:详细PCB包括：AnFR4plateorblock,andCopperlayersmodeledasconductingthinplatesTheCompactPCBModelincludes:简化PCB模型包括：ANon-isotropicplateIn-planeconductivityismuchhigherthanthenormalconductivityThecopperlayersarenotmodeledseparately,43,PCBModeling,IcepakmenuforPCBcreation,44,PCBModeling,CompactPCBModel,DetailedPCBModel,K(in-plane)=27W/mKK(normal)=0.34W/mK,FR4(K=0.3W/mK),Copperlayers,Non-Isotropicmaterial,45,ICPackages,ICPackages,IC封装,46,ICPackages,47,ICPackages,AnICpackageisthehousingthatprotectsthechipfrom:IC封装是为了保护的空间Environmentalstresssuchashumidityandpollution环境压力如湿度，污染Mechanicalstresssuchascrackingandoverheating机械压力如破裂，过热Electricaldischargeduringhandling操作过程中的放电TheICpackagemustalsoprovide:IC封装必须提供：Interfacefortesting用于测试的接触面Electricalinterconnectiontothenextlevelofpackaging与PCB连接的电子连接面AnICpackagemustsatisfytheaboverequirementswhilemeetingotherobjectssuchascost,qualityandreliabilityIC封装还应满足其它要求如成本，质量和可靠性Itisthefirstlevelofelectronicpackaging它是电子封装的第一级ThesecondlevelbeingPackage-PCBassembly第二级是封装-PCB装配ThethirdlevelisPCBassemblytotheBackplane第三级是PCB与底板装配,48,LevelsofPackaging,System-levelAssembly,BackplaneAssembly,ICPackage,PCBAssembly,Chips,49,ICPackages,Packagesmaybeclassified(bymountingmethod)as:封装可以分为（按安装方法）：Through-holetype(THT)穿孔型Surfacemounttype(SMT)表面安装型Specialpackages特殊类型THTpackageshavepinsthatareinsertedintoholesdrilledacrossthethicknessofthePCBTHT封装的pins穿过PCB上的孔TheyareusedinpackagewhereboardspaceisnotpremiumExamplesareDIP,PGA,etc.SMTpackageshaveflatstructurewiththeleadpinssoldereddirectlyintotheconductorpatternonthesurfaceofthePCBSMT封装的pins直接焊接在PCB的表面TheyareusedinhighpindensitypackagesExamplesareQFP,QFJ,etc.,50,THTPackageExamples,ZIP(ZigzagIn-linePackage),DIP(DualIn-linePackage),51,SMTPackageExamples,QFP(QuadFlatPackage),SSOP(ShrinkSmallOutlinePackage),52,ICPackages,53,ICPackages,Specialpackagesarepackagessuchas:特殊类型封装如：Chip-on-board(COP)packageswherethechipismountedandsealedonthePCBCOP封装被安装并密封在PCB上TapeCarrierPackages(TCP)带载封装Memorymodules记忆模块Powerdissipationperchipisafunctionof:每种芯片耗散功率是下列参数的函数：Frequency,f频率Capacitance,C电容Voltage,V电压Gatecount(I/Ocount)门数Morespecifically:即：Power=F(f,C,V2,Gatecount),54,ICPackages,Logic(ASIC)chipshavemoregates(andhenceproducemorepower)thanmemorychips逻辑芯片比记忆芯片有更多的门Thus,fromcoolingperspective,logicchipsaremoredifficulttocoolthanmemorychips因此，从散热的观点来看，逻辑芯片比记忆芯片要难,55,ExamplesofICPackages,PlasticBallGridArray(PBGA)LowConductingtop(1W/m/K)顶部的导热率低(1W/m/K)PCBtypeMaterialSubstratePCB材料型底部Smalldie(1/3ofpackagesize)小尺寸dieInterconnectisatthedietop,andsoisthepowerdie顶部与热源内部相连,56,ExamplesofICPackages,TapeBallGridArray(TBGA)HighConductingTop(copper)顶部的导热率高TapeSubstrate(thinnerthanPBGA)Substrate比PBGA薄Dieis1/3ofPackageInterconnectisatthediebottom,andsoisthepower,57,ExamplesofICPackages,FinePitchBallGridArray(FPBGA)LowConductingtop(1W/m/K)顶部的导热率低(1W/m/K)PCBtypeMaterialSubstrateChipScalePackage(CSP)(dieisabout70%ofpackagesize)Interconnectisatthedietop,andsoisthepowerModelisexactlythesameasPBGA模型与PBGA相似,58,ExamplesofICPackages,FlipChipCeramicBallGridArray(Flipchip-CBGA)Exposeddie,optionalheatspreader,NowireBonds外露的die,可选的散热板，无线CeramicSubstrate(K15W/m/K)陶瓷SubstrateInterconnectatdiebottom;Interconnectjunctionsisattachedtosolderbumps,whichinturnconnectssignaltracesModelisexactlythesameasPBGA模型与PBGA相似,59,ExamplesofICPackages,PlasticQuadFlatPack(PQFP)LowConductingovermolding(1W/m/K)顶部的导热率低Dieisabout1/3ofpackage;NosubstrateInterconnectisatthedietop,andsoisthepowerConnectsperipherallytoPCBcircuitryviagoldwireleads,60,ExamplesofICPackages,ABGA(AdvancedBGA),61,PackagewithCeramicSubstrate(CBGA),ConductionPaths,62,TypesofPackageModels,DetailedModels详细的模型Detailsofthepackageareincludedinthemodel,suchassolderballs,leads,die,encapsulation,substrate,etc.UsedforPackageLevelModelingandmeasurementvalidationCompact(Semi-Detailed)Models简化的模型(半详细)ThemaincomponentsaremodeledusingThickorThinconductingplates,componentssuchasthedie,solderballs,substrate,etc.ThismodelisusedtoreducethemeshcountThereissomedropinaccuracyasaresultGoodforBoardandSub-systemLevelModeling,63,TypesofPackageModels,Network(Resistance)Models网络模型PackagemodeledusingresistancenetworkThenetworkcanbetwo-resistornetwork,Starnetwork,Shuntnetwork,etc.TheusermustsupplytheresistanceValuesforthenetworkTheresistancevaluesmaybeobtainedfrommanufacturers,experiments,ordetailedpackagemodels,64,DetailedPackageModel,Mold,SolderBalls,Die,Substrate,WireBond,CuTrace,DiePad,65,Semi-DetailedPackageModel,DetailedModel,Semi-detailedModel,66,NetworkPackageModel,Two-ResistorNetworkModel,Six-Resistor(Star)NetworkModel,3,9,3,9,2,2,Rjc=3Rjb=9,Rjc=3Rjb=9Rjs=2,67,DefinitionofPackageResistances,qjc=(TdieTcase)/QcaseTdie=dietemperatureTcase=casetemperatureQcase=heatdissipatedthroughthecaseqjb=(TdieTbot)/QboardTbot=temperatureofpackagebottomQboard=heatdissipatedfromthepackagebottomtotheboardqja=(TdieTamb)/QcaseTamb=ambienttemperatureQdie=totalheatdissipatedfromthepackage,68,FactorsAffectingChipResistances,qjadependson:与下列因素有关：DiepowerDie功耗Chipsize芯片大小Natureofconductionpaths(leadframes,etc.)传导途径Airvelocity气流速度PCBtypeandpopulationPCB类型和数量qjadecreasesas:随下列因素而降低chipsizeincreases芯片尺寸增大Airvelocityincreases气流速度增加conductionpathsimprove传导途径改善Theresistancesmeasuredforasinglepackageonaboardareusuallylowerthanthoseobtainedonapopulatedboard,andmayonlyserveasalowerbound板上单个封装测量的阻尼比很多封装在板上测量的结果要低,69,FactorsAffectingChipResistances,70,TypicalValuesofqja,Source:NECPackages,71,TypicalValuesofqja,Source:NECPackages,72,TypicalValuesofqja,Theeffectofboardconfigurationonqja,Source:Motorola,73,DetailedvsNetworkModels,Tcase73-88C,Tcase80C,DetailedModel,NetworkModel,Rjc=20Rjb=40,Airvelocity=1m/s,(Rja=44),(Rja=40),74,Exercise1:PBGAModel,Exercise1:PBGAModel,练习1：PBGA模型,75,Exercise1:PBGADetailedModel,1.CreateaCabinet生成一个cabinetUnderModel/Cabinet,createacabinetwiththefollowingspecifications:(Alldimensionsinm)XS=-0.0375XE=0.0375YS=-0.02YE=0.0075ZS=-0.0375ZE=0.0375,76,Exercise1:PBGADetailedModel,2.CreateanInletOpening生成一个入口UnderModel/Openings,createaninletopeningwiththefollowingdimensionsandvelocityspecification:Plane:X-YXS=-0.0375XE=0.0375YS=-0.02YE=0.0075ZS=-0.0375Zvelocity=0.3m/s,InletOpening,77,Exercise1:PBGADetailedModel,OutletOpening,3.CreateanOutletOpening生成一个出口UnderModel/Openings,createanoutletopeningwiththefollowingdimensions:XS=-0.0375XE=0.0375YS=-0.02YE=0.0075ZS=0.0375,78,Exercise1:PBGADetailedModel,4.PCBMaterial材料UnderModel/Materials/Solid,createaPCBmaterialwiththefollowingspecifications:name:pcb-materialSub-type:otherConductivity:1.0W/m-KToggleonOrthotropic,andassign:X=25W/m-KY=0.3W/m-KZ=25W/m-K,79,Exercise1:PBGADetailedModel,5.CreateaPlate生成一块板UnderModel/Plates,createaplateusingthefollowing