材料专业外文翻译-导体和半导体材料

中文3550字作者R.Snyder,Member FrederickI.Mopsik国籍：America出处：IEEETRANSACTIONSONINSTRUMENTATIONANDEASUREMENTAPrecisionCapacitanceCellforMeasurementofThinFilmOut-of-PlaneIII:ConductingandSemiconductingMaterialspaperdescribestheconstruction,calibration,anduseofaprecisioncapacitance-basedmetrologyforthemeasurementofthethermalandhygrothermal(swelling)expansionofthinfilms.Itisdemonstratedthatwiththisversionofourcapacitancecell,materialsranginginelectricalpropertiesfrominsulatorstoconductorscanbemeasured.Theresultsofourmeasurementsonp-type<100>-orientedsinglecrystalsiliconarecomparedtotherecommendedstandardreferencevaluesfromtheliteratureandareshowntobeinexcellentagreement.IndexTerms—Capacitancecell,coefficientofthermalexpansion(CTE),guardedelectrode,highsensitivitydisplacement,innerlayerdielectrics,polymers,thinfilms.INTRODUCTIONTHEcoefficientofthermalexpansion(CTE)isakeydesignparameterinmanyapplications.Itisusedforestimatingdimensionaltolerancesandthermalstressmismatches.Thelatterisofgreatimportancetotheelectronicsindustry,wherethermalstressescanleadtodevicefailure.Foraccuratemodelingofthesesystems,reliablevaluesareneededfortheCTE.Traditionally,displacementgaugetechniquessuchasthermomechanicalanalysis(TMA)havebeenutilizedfordeterminingtheCTE.However,standardtestmethodsbasedonthesetechniquesarelimitedtodimensionsgreaterthan100mm[1-2.]Thisisproblematicformaterialswhichcanbeformedonlyasthinlayers(suchascoatingsandcertaininnerlayerdielectrics).Additionally,thereissomequestionastowhethervaluesobtainedonlargersamples(bulkmaterial)arethesameasthoseobtainedforthinfilms,evenwhentheeffectsoflateralconstraintsareincludedinthecalculations.Ithaslongbeenrecognizedthatcapacitance-basedmeasurements,inprinciple,canofferthenecessaryresolutionforthesefilms.Forapairofplane-parallelplatecapacitors,ifthesampleisusedtosetthespacingoftheplatesd whilebeingoutsideofthemeasurementpath,thenforaconstanteffectiveareaoftheplatesA,thecapacitanceina AvacuumC

vac

isgivenbythewell-known

vac

0 (1)dwhere

isthepermittivityoffreespace8.854pFm).Withthesample0 0outsideofthemeasurementpathandonlyairetweentheelectrodes,thevacuumcapacitanceisobtainedromthemeasuredcapacitanceC byC Cvac air

(2)whereair isthedielectricconstantofair.Inthreepreviouspapers,thedesignanddatareductiontechniqueswerepresentedforourthree-terminalcapacitance-basedmetrologyforthinpolymerfilmmeasurements.Thefirstpaper(I)describedtheinitialdesignbasedongold-coatedZerodur.However,severalproblemswereencountered.ItwasdiscoveredthatZerodurdisplaysferroelectricbehavior,withanapparentCurietemperatureof206℃asdeterminedbyfittingwithaCurie–Weisslaw.TherapidchangeinthedielectricconstantoftheZeroduralongwithacouplingfromthecentralcontactthroughtheguardgaptothehighelectrodecreatedanapparentnegativethermalexpansion.Thesecondproblemwiththeinitialdesignwaswiththegoldcoating.Thiscoatinghadthetendencyto―snowplow‖whenscratchesformedinthesurfacecreatingraisedareaswhichwouldresultinshortswhenmeasurementswereperformedonthinsamples.Thesecondproblemwiththegoldwasthatitunderwentmechanicalcreepunderloading.Toresolvetheseproblems,anewelectrodewasdesignedfromfusedquartzcoatedwithnichrome.Agroovefilledwithconductivesilverpaintwasaddedtothebacksideofthebottomelectrodearoundthecentralcontacttointerceptanyfieldlinesbetweenthecentralwirecontactthroughtheguardgaptothehighelectrode.Thenewdesignwasdescribedinthesecondpaper(II)alongwiththermalexpansionmeasurementson<0001>-orientedsinglecrystalsapphire(AlO2 3

)anda14-m thickinnerlayerdielectricmaterialwasrecognizedinIIthatthedatareductionwassimpleaslongastheairfillingthegapbetweenthecapacitorplateswasdry.However,toexpandtheutilityofthecapacitancecelltohygrothermalexpansion(i.e.,swellinginahumidenvironment),thethirdpaper(III)describedthedatareductiontechniquesnecessaryforuseofthecapacitancecellunderhumidconditions.Fig.1.Schematicoftheelectrodes.Notethattheshadedareascorrespondtothenichromecoating.TheresolutionoftheinstrumentwasdeterminedinIIandIII.Fordry,isothermalconditions,thecapacitancecellcanmeasurerelativechangesinthicknessontheorderof107 ,fora0.5-mmthicksample;thiscorrespondstoaresolutionontheorderof51011m.Underdryconditionsinwhichthetemperatureischanged,thereproducibilityofarelativethicknesschange(e.g.,forCTEmeasurement)isontheorderof106

.Finally,underhumidconditions,theultimateresolutionisprimarilyafunctionoftemperature—theactualvaluesofwhicharegiveninIII.InII,adeficiencywasrecognizedinthedesign.Neithersemiconductingorconductingmaterialscouldbeusedasthematerialfortesting.Thiswasespeciallythecaseforsilicon,whichformsaSchottkybarrierwithnichromeandactsasavoltagerectifier.Additionally,becauseofthenatureoftheinterface,the1kHzmeasurementfrequencygeneratesultrasoundwhichresultsintheepoxycontactsbeingshakenloose.WementionedbrieflyinIIthatifthetopelectrodehadaguardringadded,thesamplecouldbeheldatzeropotentialandthiswouldnolongerbeaproblem.Todemonstratethis,weconstructedsuchacapacitancedesignandtestingofwhicharedescribedinthispaper.CAPACITANCECELLDESIGNElectrodeDesignBecausetheconstructionoftheelectrodeswasthoroughlydescribedinII,alessdetaileddescriptionwillbegivenwithemphasisonthechangesinthedesign.Theelectrodeswereconstructed,asbefore,inthefollowingmanner(seeFig.1).10cm2cmcylindricalblanksoffusedquartzweregroundandpolishedtoopticalflatness.Smallholesweredrilledthroughthecenterofeachblanksothat16gaugewirecouldbeinsertedintothem.Thewireswerethencementedwithaconductingepoxy(resistivityof4104cmatAsecondholeandwirewerethenaddedtoeachblankapproximately0.75cmfromtheedgeoftheblanks.Acoatingofnichromewasthenaddedsuchthatitcoveredallsurfacesexceptforasmallareaaroundthebackoftheblanks.Aguardgapwasscribedonboththetopandbottomelectrodessuchthatnomaterialwasraisedwhichcouldcauseashort.Onthebottomelectrode,theguardgapwasscribedona3cmdiameter,andonthetopelectrodeitwasscribedona6cmdiameter.Inthebottomelectrode,a1cmdiameterwellwascutintothebackoftheblankwhichextendedtowithin5mmofthefrontsurface.Thiswellwasthenfilledwithathinconductivesilverpaint.Thepaintconnectedtheouterguardring’smetallizationtotheedgeofthewell.Fig.2.Schematicoftheassembledcapacitancecell.CellAssemblyandCapacitanceMeasurementsTheholderdescribedinIIwasemployedforthemodifiedcell.Inthisversionofthecapacitancecell,bothconductorsofthesemirigidcoaxiallinewereconnectedtothetopelectrode.Thecenterconnectorandbraidwereconnectedtothecenterareaandouterguardring,respectively,byfine30gaugewirecoils.ThecoilswereterminatedwithcenterfemalecontactsfromBNCconnectors,whichcouldbeeasilyconnected/disconnectedtothe16gaugetinnedcopperwirethatwasepoxiedintotheelectrodes.AschematicoftheassembledcellisshowninFig.2.ThefemaleBNCconnectoronthebrassholder(bottomelectrode)wasconnectedtothelowterminal,andthefemaleBNCconnectoronthesemirigidcoaxiallinewasconnectedtothehighterminal.AllconnectionsfromthecapacitancecelltothebridgewereperformedusingTefloninsulatedlownoisecables.Thecapacitancemeasurementswereobtainedusingacommercialautomatedthree-terminalcapacitancebridgewhichusesanoven-stabilizedquartzcapacitorandhasacitedguaranteedrelativeresolutionofbetterthan5107

pF/pFfortherangeofcapacitancesusedwiththiscell2500A1kHzUltra-PrecisionCapacitanceBridgewithOptionE).(Notethatthe―useful‖relativeresolutionissuggestedbythemanufacturertobetypicallyafactorof10ormorebetterthatthecitedrelativeresolution.)Thecapacitancebridge’swasverifiedagainstaNationalInstitutefsdy(NIST)dderdifferencebetweenthetwowaswithinthecapacitor’suncertainty.Allmeasurementswereperformedinatemperature/humiditychamberequippedwitha90℃dewpointairpurge.Thecellwasequilibratedateachtemperatureuntiltherelativefluctuationsinthevacuumcorrectedcapacitancewerenomorethan10710pF/pF.Barometricpressurewasmonitoredusingadigitalpressuresensorwithamanufacturer’sstateduncertaintyof0.1mmHg(13Pa).AsstatedpreviouslyinII,thetemperatureofthecellwascalibratedintermsofthechambertemperaturewitharesistancetemperaturedevice(RTD)mountedtothecellwiththermallyconductingpaste.TheRTDwascalibratedagainstaNISTcertifiedITS-90standardreferencethermometer.AsinII,becauseweareusingadryairpurge,wecanusetheidealgaslawcorrectiontodeterminethemolarvolumeoftheairvtocalculateCair vacvair

RT（3）pWhereT---absolutetemperature;P---pessure;R---gasconstant(R8.314507Lkpamol1K1)[12].Fromthisandthevalueofthemolarpolarizationofdryairobtainedfromtheliterature,P4.31601103mol[13],thedielectricconstantoftheairseparatingtheelectrodesis air P air v11Pairvaieair

aie (4)MEASUREMENTSCellCalibrationTouse(1)tocalculatethethicknessofthesample,theeffectiveareamustbeknown.Todeterminethisvalueasafunctionoftemperature,asinII,wecalibratedtheareaandareaexpansionthroughtheuseofZerodurspacerswiththicknessesofapproximately2.0mm.AsinII,theactualdimensionsoftheZerodurspacersweremeasuredinaballtoplaneconfigurationwithaspeciallydesignedcaliperequippedwithalinearvoltagedisplacementtransducer(LVDT)thathadaresolutionof1104mm.ThecellwasassembledwiththeZerodurspacersusingthesamplepreparationdescribedinII.Measurementswereperformedat0℃,25℃,50℃,75℃,100℃,125C,and150℃.Thecellwascycledthroughthisrangeoftemperaturethreetimes,andthevaluesforC werevacdeterminedforeachrunafteraveragingallthepropertiesoverapproximately1husing10sincrements(atotalof360datapoints)afterequilibriumwasachieved.TheareaAwascalculatedusingtheroomtemperaturethicknessmeasurementsandthevalueforC .Allsubsequentdeterminationsof A,athigherandlowertemperatures,werevaccorrectedfortheslightexpansionandcontractionoftheZerodurasafunctionoftemperature0.05106K1).TheresultsoftheeffectiveradiusoftheelectrodeZerodurasafunctionoftemperatureareplottedinFig.3.Fig.3.EffectiveradiusofthebottomelectrodeasafunctionoftemperatureobtainedbymeasurementsusingZerodurandcorrectingforitsslightexpansion.Fig.4.Relativeexpansionofthe<100>-orientedsinglecrystalsiliconasafunctionoftemperature.Thelineisaplotofthedatafromp-TypeDoped<100>SingleCrystalSiliconTodemonstratetheabilityofthecelltomeasuresiliconandtoprovideaccuratevaluesforthermalexpansion,a0.6-mmthickwaferofsingle-sidepolished,backsidestressrelieved,p-type,<100>-orientedsinglecrystalsiliconwitharesistivityof15 cmwasn(by)oe.hescm2.ewerethencleanedwithultrapuredistilledwaterandethanol.ThecellwasassembledinthesamefashionaswasdescribedinIIandwasplacedinavacuumovenatambienttemperaturesforapproximately1htoeffectivelywringthesample.3.Measurementswereperformedat50℃,75℃,100℃,125℃,andaminimumoftwotimeseach.(Note:Nopointwastakenat0℃duetoproblemswiththecompressorintheenvironmentalchamber.)ThewaferthicknesswasdeterminedusingtheeffectiveradiusversustemperaturedatashowninFig.3.TheresultsofthisanalysisareshowninFig.4alongwiththerecommendedexpansiondataonsiliconobtainedshouldbenotedthatthestandardreferencedatawasdefinedrelativetowhereaswehavemeasured,forconvenience,relativeto25℃.Therefore,thestandardreference,relativeexpansiondatawasshiftedinFig.4byanamountSequaltoST5KwhereT istheCTEattemperatureTtakenfromItisapparentthatthetwosetsofdataagreewithintheexperimentaluncertainty.(Theerrorbarissmalleronthe25℃datapointthanonthehighertemperaturesduetothefactthatmorerepeatrunswereperformed,whichreducedtheuncertaintyforthatdatapoint.)Thisdemonstratesseveralkeyconclusionsregardingthecapacitancecell.First,thelimitationsofthepreviousdesignhavebeeneliminated;siliconandconductingsamplescanbemeasured.Second,theresultsshowthatthecapacitancecellproducesdatathatagreewithliteraturedata.Finally,wehavefurtherdemonstratedtheadvantageofourtechniqueformeasurementofthinsamplesovercommerciallyavailableTMAs.Thevalidityofthisstatementcanbeshownbyconsideringtheresultsofaroundrobinstudy.ThisstudywasperformedamongresearchersatNIST,IBMEndicott,DEC,MicroelectronicsandComputerTechnologyCorporation,NavalSurfaceWarfareDivision,CALCEElectronicProductsandSystemsCenterattheUniversityofMaryland,CornellUniversity,UniversityofTexasatAustin,PurdueUniversity,andtheSemiconductorResearchCorporation(SRC)onthemeasurementoftheCTEofsinglecrystal<100>siliconusingvariouscommercial1.1765-mmthicksampleof<100>singlecrystalsiliconwasusedbyallparticipants.AllreportedvaluesfortheCTEofsiliconwerebelowtheliteraturevaluesforthecorrespondingtemperaturerangesby15%to40%.Oursamplewasapproximatelyhalfasthickastheirsample,yetourvaluesarewithintheexperimentalerror.(Itshouldberecalledthatourtotalprecisionisindependentofactualthicknessandthemainerrorisduetoelectrode/sampleinterfacialeffects.Therefore,hadweusedthethickersample,aswasusedintheroundrobinstudy,theerrorinourresultswouldhavebeenreduced.)Inclosing,itshouldbementionedthatsincewasthe―worstcase‖scenarioforthenewcapacitancecell,itwasdeemedunnecessarytoperformmeasurementsonsinglecrystalsofametallicsamplewhichhaveamuchhigherCTE.However,asinglemeasurementwastakenonthesiliconbyconnectingthebraidsfromthehighandlowterminalstogethershortingthetwoguardringsasifitweredonebyametallicsample.Themeasuredcapacitancewasunchanged;thisthereforedemonstratedthatconductingmaterialscanbemeasured.CONCLUSIONSWehavepresentedthedesignsandimplementationofourcapacitancecellforthemeasurementofconductingandsemiconductingmaterials(aswellasdielectrics).Thethermalexpansiondata,obtainedwiththenewversionofourcapacitancecell,onp-typedopedsinglecrystalsiliconhavedemonstratedboththeabilityofthecelltomeasuresiliconandconductingsamplesandtheabilityofthecelltoprovideaccurateCTEdataonthesetypesofmaterials.Asaresult,itisapparentthatthismetrologycanalsobeappliedtothinpolymerfilmsdepositedonsiliconsubstrates.Furthermore,thiscellcanalsobeusedtostudythehygrothermalexpansion(swellingduetothepresenceofmoisture)byutilizingthedatareductiontechniquesdescribedinIII.Accordingly,thistechniqueshouldbeespeciallyusefultothemicroelectronicspackagingindustryforthecharacterizationofinnerlayerdielectricsaswellascompositestructures.ACKNOWLEDGMENTTheauthorswouldliketothankDr.J.R.EhrsteinintheSemiconductorElectronicsDivisionatNISTforprovidingthesiliconsample.一种精密电容测量薄膜平面扩张的第三部分：导体和半导体材料摘要本文介绍了设计、校准，并且使用精密电容基础计量学来测量薄膜的热、湿热（肿胀）型<100单晶硅结果与参考文献比较，得到了良好证明。电容、热膨胀系数介质、聚合物、薄膜简介热膨胀系数（CET）是许多应用的一个关键设计参数。它是用来估算尺寸和热应力的错位。热应力是十分重要的，它会导致电子行业中的设备故障。系统的精确建模，可靠性的测定都需要热膨胀系数（CET）的核定。传统上的位移测量方法如热应力分析（TMA）可以用来确定热膨胀系数0m的基础上。这些材料局限于只能作为薄层得形成（如涂料和内层介电层）。此外，在更大的样本（散装材料）甚至当薄膜横向约束的影响下所获得的结果是否与理论值一致。人们很早就认识到，在原则上，用过电容测量可以为薄膜提供必要的参数。d，然后两极板相互A，其真空电容量为C

0A

(1)vac d 是真空介电常数8.854pFm），只用来测量的外极板，两极板间只0 0有空气，空电容量C表达式为C vac

Cair

(2)式中

air

是空气介电常数在前三篇论文，描述设计和数据还原技术的发展现状，并提出了三端口电容(I)的初步设计。然而遇介电形成的表面划伤的地区会导致测量误差。第二个关于涂金的问题是它经历载荷下的力学蠕变。极之间的环行线接触到任何领域。第二篇论文介绍了新的设计，单晶蓝宝石（氧化二铝14m为当电容极板间填充的空气是干燥时，数据分析是简单的。然而，电容还需测量薄膜的湿热膨胀（例如，在一个潮湿的环境中的膨胀），论文Ⅲ中描述了电容在高温高湿条件下数据分析的必要技术。1电极原理图。注意阴影部分对应的镍铬合金涂层在论文Ⅱ、Ⅲ中已经确定仪器的分辨率。干燥、等温条件下，电容对于一个10751011m条件下改变温度，相对厚度变化（例如热膨胀系数）大约为106。最后，在潮湿的条件下，最终解决温度的影响——这个将在论文Ⅲ中得到