第1讲-MEMS技术概述

微/纳制造工艺技术Microfabricationtechnology第一讲：MEMS技术概述乔大勇下载课件请加入微纳制造工艺技术群：436168111OutlineWhatisMEMS13HistoryofMEMS2WhyMEMS1、WhatisMEMS10-610-510-410-310-210-1100101尺寸(米)CellphoneDicedchipMEMSTVHumanAntHumanhairTransistor1、WhatisMEMS10-1010-910-810-710-6尺寸(米)AtomDNABacteriaNanotubeNanomanipulationNEMS1、WhatisMEMSGeneralDefinitionofMEMSMicro-Electro-MechanicalSystems(MEMS)istheintegrationofmechanicalelements,sensors,actuators,andelectronicsonacommonsubstratethroughtheutilizationofmicrofabricationtechnology.1、WhatisMEMSGeneralDefinitionofMEMSMicro-Electro-MechanicalSystemsBatchfabrication(e.g.,ICtechnology)EnergyConversion(Electricaltoandfromnoelectrical)UltimateGoal(Solutiontorealproblems,notjustdevices)1、WhatisMEMSGeneralDefinitionofMEMSMulti-Engineering-MixedSystems跨多学科的技术为主导的（硅工艺、LIGA等)系统知识整合1、WhatisMEMSGeneralDefinitionofMEMSManufacturing-Enhanced-MicroSystems加工技术(牺牲层、深刻蚀、键合等）牵引的系统微小型化1、WhatisMEMSMEMSMarksScale:Fromabove1umtobelow1mmManufacture:BatchFabricationTechnologyFunction:Micro-mechanics,electronics,fluidics,optics.1、WhatisMEMSGeneralMEMSChallengesThehightoolingcostsAstate-of-the-artsiliconfoundrycosts＄1BThecomplexityofMEMSdesignTypicalMEMSdevicesmanipulateenergyinseveraldomains.Thedesignermustunderstand,andfindwaystocontrolcomplexiterationsamongthesedomainsNon-standardFabricatonprocessUptonow,fabricationprocessrelatedmicrodevicescannotbebatchfabricatedbyfoundryprocess.ThedesignofmicrodevicesisnotindependenttofabricationprocessasICdid.2、WhyMEMSInScienceTosatisfyhuman'sinherentdesiretoexploretheunknownworld,scalinglawInTechnology&EngineeringBatchfabrications(lowcost)Smallsize(newapplications)Performance(improvement)2、WhyMEMSInScience-Surface/VolumeSurface~(length)2orS~L2Volume~(length)3orV~L3Surface~(volume)2/3orS~V2/3Inthelastequation,welearnthatasthevolumeofabodyisincreased,itssurfacedoesnotincreaseinthesameproportion,butonlyinproportiontothetwo-thirdspowerofthevolumeS=kV0.67orS/V=kV0.67/VorS/V=kV-0.33Thelatterexpressionrepeatsanotherwell-knownfact:smallerbodieshave,relativetotheirvolumes,largersurfaceareasthanlargerbodiesofthesameshapeSizeandheatgain(L3)andloss(L2)Smallanimalsalwaysappeartobefeedingtostaywarm2、WhyMEMSInScience-Surface/Volume水黾在水面行走2、WhyMEMSInScience-StandingStanding:–Thediameterofatallhomogeneousbodysuchasatreemustincreaseas3/2ofitsheight(L3/2).–YoungandsmalltreesappearslenderandoldandtallonesappearsquatorstuntedNatureseemstofavorsmall2、WhyMEMSInScience-JumpingJumping:–Theworkdoneinleapingupisproportionaltothemassandheight(h)ofthejumpW~Mh–Poweravailableisproportionaltothemassofthemuscle(m)whichisproportionaltothemassoftheanimalorW~mthushtendstobeconstantirrespectiveoftheanimal跳蚤，2～5毫米长，一次可以跳20厘米高，30厘米远Natureseemstofavorsmall2、WhyMEMSInScience-StrengthandWeightStrength∝L2–SmallthingstendtobestrongerWeight∝L3Natureseemstofavorsmall2、WhyMEMSInScience-ElectrostaticElectrostatics(L2)scalesbetterthanmagnetics(L4)somostElectrostaticdevicescanbeoperatedinairwithoutbreakingdownNatureseemstofavorsmall2、WhyMEMSInScience-Electrostatic在常压情况下，空气击穿场强为3×106V/m，对于静电驱动MEMS而言，其结构的间距通常在十几微米以内，则按上述标准，其击穿电压仅为几十伏，然而在实际应用中很多的驱动电压都达到了上百伏。研究表明，当间隙减小到一定程度后，其发生击穿时所对应的电场强度将随着间隙的缩小而逐步增大，如Bart和BushVishniac等人在实验中发现在2μm和12.5μm空气间隙上所对应的击穿电场分别为108V/m和3.2×107V/m。NatureseemstofavorsmallMarcMadou,FundamentalsofMicroFabrication,NewYork:CRCpress,1997,406-412.PaschenCurveinair2、WhyMEMSInScience-RotationMassmomentofinertia:I=∫r2dm∝L5(ThisisafifthorderexpressionofrAsmallmotorwillreachtopspeedinafractionofasecond,largemotorsmayrequiresecondstoreachfullspeedNatureseemstofavorsmall2、WhyMEMSInScience-RunningRunning:–Numbersofsteps(n)theanimalmusttakeperunitdistancemovedisinverselyproportionaltothelineardimension,or1/3ofitsmass:(I)n~1/L~M-1/3–Thework(II)(W)involvedperkmisthen~MM-1/3=M2/3,andtocompareallanimalswedividebythebodymassor:work(III)Wperkgperkm~M2/3M-1=M-1/3Thelatterexpressionsaysthattheworkrequiredtomove1kgofanimaloveragivendistancedecreaseswithincreasingbodymass(muchlessstepsareneeded!)2、WhyMEMSInScience-SwimmingSwimming:–Thebiggerthefishorshipthefasterittendstogo,butonlyintheratioofthesquarerootoftheincreasinglength.–V:thevelocity(v)theswimmingbodycanattain–W:thework(W)itcando,∝L3–R:theresistance(skinfiction)toovercome.∝L2lllRWV==∝232、WhyMEMS新的加工技术（能够大批量低成本复制）新的设计方法（用EDA工具设计机械结构）微小型化的（应用）需求电视屏幕不需要小型化电视机要小型化汽车不需要小型化压力计、加速度计、陀螺需要小型化炮弹不需要小型化引信需要小型化InTechnology&Engineering2、WhyMEMSMEMSIMUConventionalIMUMass:5gramsSize:18mm×18mm×10mmPower:~1mWSurvivability:100,000gCost:＄1795Mass:1587.5gramsSize:15cm×8cm×5cmPower:~35WSurvivability:35gCost:＄20,000MEMSENSE:AccelRate3D-TriaxialAccelerometerandGyroMiddleEastTechnicalUniverstiy,TurkeyInTechnology&Engineering2、WhyMEMSMEMSMobileConventionalMobile姿态识别GPS定位卷轴菜单动感游戏环境感知闪信投影放映健康监测通话、短信息InTechnology&Engineering3、HistoryofMEMS195019701980199020001960MetalSacrificialProcess(USpatent)BJTTransistorICHNAEDPAnodicbondingPressureSensor(Honeywell)KOHSiliconPressureSensor(Motorola)Siasamechanicalmaterials(Petersen)Thermo-pneumaticvalve(Redwood)SFBSFBPressureSensor(NovaSensor)TMAHDRIE!!XeF2/BrF3Bio