1、外文原文：http:/ 中文 2800 字 DevelopmentofMEMSVerticalPlanarCoilInductorsThroughPlasticDeformationMagnetic Assembly (PDMA) JinghongChen*,JunZou*,ChangLiu*andSung-Mo(Steve)Kang* AgereSystems,Holmdel,NJ07733DepartmentofElectricalandComputerEngineering, UniversityofIllinoisatUrbana-Champaign,Urban
2、a,IL61801JackBaskinSchoolofEngineering,UniversityofCalifornia,SantaCruz ABSTRACT Thispaperpresentstheresultsofthedevelopmentofaverticalplanarcoilinductor.Theplanarcoilinductorisfirstfabricatedonsiliconsubstrateandthenassembledtotheverticalpositionbyusinganovel3-Dimensionalbathscaleself-assembl
3、yprocess(PlasticDeformationMagneticAssembly(PDMA).Inductorsofdifferentdimensionsarefabricatedandtested.TheS-parametersoftheinductorsbeforeandafterPDMAaremeasuredandcompared,demonstratingsuperiorperformanceduetoreducedsubstrateeffectsandalsoincreasedsubstratespacesavingsfortheverticalplanarcoilinduct
4、ors. Key wordsMEMS,planarcoilinductor,qualityfactor,PDMA,resonancefrequency. 1 INTRODUCTION Withthedevelopmentofintegratedwirelesscommunicationsystems,on-chipinductorswithsatisfactoryperformance(enoughqualityfactorandselfresonantfrequency)arerequired.However,theconventionalplanarcoilindu
5、ctorsuffersfromsubstratelossesandparasiticssinceitisdirectlyfabricatedontoconductivesubstrateoveraverythindielectriclayer1. Inrecentyears,muchefforthasbeenmadetoimprovetheperformanceofplanarcoilinductors.Metalmaterialswithhigherconductivityorthickermetallayersareutilizedtodecreasetheresistanceofthec
6、oil.Meanwhile,differentmethodsareproposedtoreducethesubstratelossandparasitics,includingremovingthesubstrateunderneaththeinductor2,applyingathickpolymidelayertoseparatetheinductorfartherawayfromthesubstrate3,etc.Morerecently,planarcoilinductorslevitatedabovethesubstratearerealizedusingasacrificialme
7、tallicmode(SMM)process4.3-Dimensional solenoidon-chipinductors developed by using3-Dlaser lithographyorsurfacemicromachiningtechnologyhavealsobeendemonstrated5,6.Thispaperreportsverticalplanarcoilinductorsdevelopedbyusinganovel3-Dself-assemblyprocess-PlasticDeformationMagneticAssembly(PDMA).Experime
8、ntalresultsshowthattheverticalplanarcoilinductorsufferslesssubstratelossandparasiticsthantheconventionalhorizontalcounterparts,andthuscanachieveahigherquality(Q)factorandself-resonantfrequency.Anothermajoradvantageoftheverticalinductorsisthattheyhavealmostzerofootprintsandthusoccupymuchsmallersubstr
9、atespace. 2 PLASTICDEFORMATIONMAGNETIC ASSEMBLY(PDMA) Fig.1AschematicillustrationofaPlasticDeformationMagneticAssemblyprocess(PDMA) PDMAisthekeytechnologytorealizetheverticalplanarcoilinductors.Adetaileddiscussionofthisassemblyprocesswillbepresentedinotherpublications.Abriefintroduction
10、ofPDMAisgivenbelowbyusinga cantileverbeamasanexample.Notethattheregionnearthefixedendisintentionallymademoreflexible.First,a cantileverbeamwitha pieceof magneticmaterial attached to itstop surfaceis releasedfromthesubstrate by etchingawaythe sacrificiallayerunderneath(Fig.1(a).Next,a magneticfieldHe
11、xtisapplied,themagneticmaterialpieceismagnetizedandthecantileverbeamwillberotatedoffthesubstratebythemagnetictorquegeneratedinthemagneticmaterialpiece(Fig.1(b).Ifthestructureisdesignedproperly,thisbendingwillcreateaplasticdeformationintheflexibleregion.Thecantileverbeamwillthenbeabletoremainatacerta
12、inrestangle()abovethesubstrateevenafterHextisremoved(Figure1(c).Byusingductilemetal(e.g.gold)intheflexibleregion,agoodelectrical connection betweentheassembled structureandthesubstratecanbeeasilyachieved,whichissuitableforRFapplications.Aftertheverticalassembly,thestructurescanbefurtherstrengtheneda
13、ndthemagneticmaterialcanberemovedifnecessary.Ifthemagneticfieldisappliedglobally,then allthestructuresononesubstratecanbeassembledinparallel. 3 DESIGNAND FABRICATION Thecorestructureoftheverticalplanarcoilinductorisidenticaltotheconventionalhorizontalone,whichconsistsoftwometallayersando
14、nedielectriclayerbetween.Asageneralrule,highconductivitymetaland lowlossdielectricmaterialshouldbeused.Inadditiontothisrequirement,thestructureoftheinductorshouldfacilitatetheimplementationofPDMA. Theverticalplanarcoilinductorutilizesone-portcoplanarwaveguide(CPW)configurationwith3testpads(Ground-Si
15、gnal-Ground)withapitchof150m.Thethreetestpadsalsoserveastheanchoroftheverticalinductorsonthesubstrate. 3.1 MaterialConsideration Goldisusedasthematerialforthebottomconductor(thecoil).Goldisaductilematerialwithhighconductivity.ItisanidealplasticdeformationmaterialfortheimplementationofPDMA.Copp
16、erisselectedasthematerialofthetopconductor(thebridge).Copperisalsoahighconductivitymetalanditsprocessingiscompatiblewiththegoldbottomconductorduringthefabrication.SiliconoxideandnitridearegooddielectricmaterialsavailableinsiliconICprocess.However,theyarenotsuitableforverticalplanarcoilinductorsduetohighinternalstressandpooradhesiononmetal
