Testing Flash Memories

TestingFlashMemories1TestingFlashTestingFlashMemoriesMemoriesByYiGongByYiGong20042004AllRightReservedAllRightReservedTestingFlashMemories2CopyRightInformationCopyRightInformationThispresentationiswrittenbyThispresentationiswrittenbyMr.GongMr.GongYiYiYoumaycopy,distributeandspreaditbykeepingauthor’snameandcopyrightinformation.2004AllRightReservedAuthorcontact:[e-mail]3CONTENTSCONTENTSffIntroducetoFlashMemoryIntroducetoFlashMemoryffFaultsinMemoriesFaultsinMemoriesffFlashMemoryFunctionalTestFlashMemoryFunctionalTestffFlashMemoryParametricTestFlashMemoryParametricTestffFlashMemoryReliabilityTestFlashMemoryReliabilityTestTestingFlashMemories4IntroducetoFlashMemoryIntroducetoFlashMemoryTestingFlashMemories5IntroducetoFlashMemoryIntroducetoFlashMemoryWhatisFlashMemory?WhatisFlashMemory?ffFlashMemoryisanEEPROMFlashMemoryisanEEPROMffElectricalProgrammableandErasableElectricalProgrammableandErasableffFlashMemoryisanNVMFlashMemoryisanNVMffNonNon--VolatileMemoryVolatileMemoryffFlashCellscanbeerasedsimultaneouslyFlashCellscanbeerasedsimultaneouslyffParallelErasableParallelErasableTestingFlashMemories6IntroducetoFlashMemoryIntroducetoFlashMemoryFlashMemoryisPopularFlashMemoryisPopular2000MemoryMarket78%12%10%DRAMNVMSRAM2000NVMMarket55%16%7%20%FlashMemoryROMEPROMOtherTestingFlashMemories7IntroducetoFlashMemoryIntroducetoFlashMemoryffFlashMemoryApplicationsFlashMemoryApplicationsffWirelessApplicationsWirelessApplicationsffPersonalDigitalEquipmentsPersonalDigitalEquipmentsffDigitalSetTopBoxesDigitalSetTopBoxesffAutomotiveApplicationsAutomotiveApplicationsffTelecomandNetworkingEquipmentsTelecomandNetworkingEquipmentsTestingFlashMemories8ffFlashMemoryMarketShare(2001)FlashMemoryMarketShare(2001)IntroducetoFlashMemoryIntroducetoFlashMemoryTestingFlashMemories9GateGateFloatingGateFloatingGateDrainDrainSourceSourceffProgram:HotElectronEjectionProgram:HotElectronEjectionffErase:FowlerErase:Fowler--NordheimNordheimTunnelingTunnelingIntroducetoFlashMemoryIntroducetoFlashMemoryFlashMemoryCellFlashMemoryCellTestingFlashMemories10IntroducetoFlashMemoryIntroducetoFlashMemoryFloatingGateFloatingGateffTheTheVtVtofaFGMOStransistorisgivenby:ofaFGMOStransistorisgivenby:ffVtVt=K=K--Q/CoxQ/CoxffK:constant,dependsontransistorpropertiesK:constant,dependsontransistorpropertiesffQ:chargeinFGQ:chargeinFGffCox:gateoxidecapacitanceCox:gateoxidecapacitanceA:NoChargeA:NoChargeB:ChargedB:ChargedTestingFlashMemories11FaultsinMemoriesFaultsinMemoriesTestingFlashMemories12FaultsinMemoriesFaultsinMemoriesFaultManifestationFaultManifestationffPermanentFaults(hardfaults)PermanentFaults(hardfaults)ffDesignfaultsDesignfaultsffBrokencomponentsBrokencomponentsffMaskfaultsMaskfaultsffNonNon--PermanentFaultsPermanentFaultsffTransientfaults(causedbyenvironment)Transientfaults(causedbyenvironment)ffcosmicray,alphaparticles,temperature,pressure,humiditycosmicray,alphaparticles,temperature,pressure,humidityffIntermittentfaults(notcausedbyenvironment)Intermittentfaults(notcausedbyenvironment)ffLooseconnection,agingcomponents,noiseLooseconnection,agingcomponents,noiseTestingFlashMemories13FaultsinMemoriesFaultsinMemoriesFailureMechanismsFailureMechanismsffElectricalStress(inElectricalStress(in--circuit)Failurecircuit)FailureffCausedbypoordesign,ESDCausedbypoordesign,ESDffIntrinsicFailureMechanismsIntrinsicFailureMechanismsffCrystaldefects,processdefectsCrystaldefects,processdefectsffExtrinsicFailureMechanismsExtrinsicFailureMechanismsffMetaldeposition,bondingMetaldeposition,bondingTestingFlashMemories14FaultsinMemoriesFaultsinMemoriesMemoryFaultClassificationMemoryFaultClassificationffFunctionalFaultsFunctionalFaultsffStuckatfaultsStuckatfaultsffCouplingfaultsCouplingfaultsffPatternsensitivefaultsPatternsensitivefaultsffParametricFaultsParametricFaultsffLeakagefaultsLeakagefaultsffInsufficientinput/outputlevelInsufficientinput/outputlevelffAbnormalpowerconsumptionAbnormalpowerconsumptionTestingFlashMemories15FlashMemoryFlashMemoryFunctionalTestFunctionalTestTestingFlashMemories16FlashMemoryFunctionalTestFlashMemoryFunctionalTestReducedFlashMemoryFunctionalModelReducedFlashMemoryFunctionalModelAddressLatchColumnDecoderCellArrayRowDecoderWriteDriverDataRegisterSenseAmplifiersRE/WE/CE/OERE/WE/CE/OEAddressAddressDatain/outDatain/outBlue:AddressBlue:AddressRed:DataRed:DataBlack:ControlSignalBlack:ControlSignalTestingFlashMemories17FlashMemoryFunctionalTestFlashMemoryFunctionalTestFunctionalTestAlgorithmsforFlashMemoryFunctionalTestAlgorithmsforFlashMemoryffZeroZero--OneOneffCheckerboardCheckerboardffGALPATGALPATffWalking1/0Walking1/0ffSlidingDiagonalSlidingDiagonalTestingFlashMemories18ZeroZero--OneAlgorithmOneAlgorithmffAlsoknownasMemoryScan(MSCAN)AlsoknownasMemoryScan(MSCAN)ffStep1:Write0inallcellsStep1:Write0inallcellsffStep2:ReadallcellsStep2:ReadallcellsffStep3:Write1inallcellsStep3:Write1inallcellsffStep4:ReadallcellsStep4:ReadallcellsStep1234W0R0W1R1AllCellsFlashMemoryFunctionalTestFlashMemoryFunctionalTestTestingFlashMemories19Fla