SMTESD介紹英文課件

1、ESD Presentation OutlinePart 1: Introduction/Background Part 2: Electrostatic Problems Part 3: ResistancePart 4: IonizationPart 5: Charge Measurement/sundae_mengESD Presentation OutlinePart 1Charging MechanismsTriboelectric ChargingInduction Charging/sundae_mengCharging MechanismsTriboelectrTriboele

2、ctrification+-+-MATERIAL CONTACT/sundae_mengTriboelectrification+-+-Triboelectrification+-+-MATERIAL SEPARATION-/sundae_mengTriboelectrification+-+-Triboelectric ChargingThe amount of charge transferred depends onTypes of materials involved Area of contactNumber of contacts Rate of separationSurroun

3、ding environment/sundae_mengTriboelectric ChargingThe amouTriboelectric ChargingGlass Human Hair NylonWool Aluminum Paper Cotton Steel RubberNickel, Copper Brass, SilverPolyester Polyurethane Polyethylene Polypropylene PVCSilicon Teflon_+Triboelectric Series/sundae_mengTriboelectric ChargingGlass Hu

4、Typical Charge LevelsTypical charge (voltage) measured for different activitiesWalking on an untreated vinyl floor12 kV for 10% RH3 kV for 55% RHWorker standing up6 kV for 10% RH400 V for 55% RH/sundae_mengTypical Charge LevelsTypical cTypical Charge LevelsTypical charge (voltage) measured on common

5、 objectsWafers5 kVWafer Carriers35 kV Quartz Ware15 kVPlastic Film40 kVSmocks10 kV/sundae_mengTypical Charge LevelsTypical cInduction Charging-+-+/sundae_mengInduction Charging-+-Charge by Induction_ _ _ _+_+/sundae_mengCharge by Induction_ _ _ProblemsElectrostatic AttractionContamination “Static Cl

6、ing”ESDDevice Damage Equipment Latch Up(ESC)/sundae_mengProblemsElectrostatic AttractiProblemsElectrostatic AttractionContamination“Static Cling”/sundae_mengProblemsElectrostatic AttractiProblemsElectrostatic AttractionContamination“Static Cling”/sundae_mengProblemsElectrostatic AttractiProblemsESDD

7、evice DamageEquipment Latch Up/sundae_mengProblemsESDhttp:/www.docin.coProblemsESDDevice DamageEquipment Latch UpOften misdiagnosed as software bugs.Induced EM DisturbanceAn Extra Pulse/sundae_mengProblemsESDInduced EM DisturbaDischarge ModelsTribocharging or induction charging + metal contact = ESD

8、Human Body Model (HBM) Machine Model (MM)Charged Device Model (CDM)are used to simulate ESD events from various sources/sundae_mengDischarge ModelsTribocharging 1500 ohmsHuman Body Model100k ohmsHVPower Supply100 pFDUT/sundae_meng1500 ohmsHuman Body Model100k Machine ModelZero ohms andlow L100k ohms

9、HVPower Supply200 pFDUT/sundae_mengMachine ModelZero ohms and100kCharged Device ModelHVPower SupplyCharge Plate/sundae_mengCharged Device ModelHVCharge PCharged Device ModelHVPower SupplyCharge Plate/sundae_mengCharged Device ModelHVCharge PGrounding (first line of defense)Grounding prevents chargin

10、g.Ground everything- floors, mats, personnel, chairs, garments, machine parts./sundae_mengGrounding (first line of defenSoft GroundsUse soft grounds to control discharges.Using dissipative materials limits discharge current to a level that does not causedamage./sundae_mengSoft GroundsUse soft ground

11、s tResistance MapInsulative1031041051061071081091013 1014 10151010 1011 1012Surface Resistance (Ohms)101102DissipativeConductiveShielding/sundae_mengResistance MapInsulative10310The Need forStandardsMany common items are rendered dissipative to control discharges.ESD control programs require qualifi

12、cation of these items. Thus a need for standardized test methods.Flooring Work Surfaces ChairsGloves Garments Packaging/sundae_mengThe Need forStandardsMany comESD Association StandardsGarments WorksurfacesFlooring ChairsPlanar Materials10V100V103104105106107108109101310101011 1012Surface Resistance

13、 (ohms)/sundae_mengESD Association StandardsGarmeTEST VOLTAGEINPUTSHIELD/GROUNDVIPoint-To-Point MeasurementsFacility GroundRegulated Test Voltage/sundae_mengTEST VOLTAGEINPUTSHIELD/GROUNDINPUTITEST VOLTAGEVSHIELD/GROUNDRTG MeasurementsFacility Ground/sundae_mengINPUTRTG MeasurementsFacility Measurin

14、g Small Objects5 lb probes are tool large to measure many objects of interest.ThermoformedTrays ClamshellsTape and Reel CarriersPick and Place Suction Cups/sundae_mengMeasuring Small Objects5 lb prIonizationInsulators cannot be grounded.Methods of Ion Generation Ionization by Radiation Electrical (C

15、orona) Ionization/sundae_mengIonizationInsulators cannot beIonization by RadiationRadioactive Decay Alpha particlesElectromagnetic Radiation Soft X-RayUltravioletInherently balanced/sundae_mengIonization by RadiationRadioacCorona Ionization+_HIGH VOLTAGE (+)/sundae_mengCorona Ionization+HIGH VOLTAGE

16、Corona IonizationHIGH VOLTAGE (+)+/sundae_mengCorona IonizationHIGH VOLTAGE Corona IonizationTypes of Electrical IonizersAC DCPulse DC/sundae_mengCorona IonizationTypes of ElecAC and Pulse DC Ionization+_HIGH VOLTAGE (AC)/sundae_mengAC and Pulse DC Ionization+AC IonizationStep up line voltageLow cos

17、tHigh airflow required to prevent recombination No control of balance/sundae_mengAC IonizationStep up line voltPulsed DC IonizationFast transport of ions without air flowMinimum recombination Good for room ionization/sundae_mengPulsed DC IonizationFast transDC IonizationAir ions will recombine and d

18、rift in the electric field.+_HIGH VOLTAGE (+)HIGH VOLTAGE (-)/sundae_mengDC IonizationAir ions will recEfficiency and Balance_+HIGH VOLTAGE (+)HIGH VOLTAGE (-)/sundae_mengEfficiency and Balance_+HITesting IonizersSuitability for ApplicationIncoming Test Periodic Verification/sundae_mengTesting Ioniz

19、ersSuitability foHow We Test IonizersTest efficiency of ion generation.How quickly will the ionizer discharge a charged surface.Test the balance of positive and negative air ions.An imbalance will charge an uncharged surface./sundae_mengHow We Test IonizersTest efficHow We Test IonizersThe instrumen

20、t used to test ionizers is the Charged- Plate Monitor./sundae_mengHow We Test IonizersThe instruDischarge (Decay) TestsEvaluate the quantity of ions produced by the ionizer.Charge a surface and measure the time to neutralize the charge.Perform for positive and negative charges./sundae_mengDischarge

21、(Decay) TestsEvaluatFloat (Balance) TestEvaluate the balance of positive and negative ions produced by the ionizer./sundae_mengFloat (Balance) TestEvaluate tCharged-Plate Monitors (CPMs)Conventional Construction/sundae_mengCharged-Plate Monitors (CPMs)Properties of Charged, Isolated Conductors_GROUN

22、DQ = CVCharges are mobile. They are free to redistribute themselves on the surface of the objectCharge (Q) is fixed.Capacitance and voltage depend on the location of the charged (conductive) object.C/sundae_mengProperties of Charged, IsolateProperties of Charged Insulators_GROUNDQ X= CVCharges are n

23、ot mobile. They cannot redistribute themselves on the surface of the object.Charges on an insulator cannot be removed by connecting the surface of the insulator to ground.Charged insulators are more troublesome to characterize.Strictly speaking, the behavior of charged insulators cannot be character

24、ized by Q = CV.XC/sundae_mengProperties of Charged InsulatoDirect Measurement of ChargeGROUNDDischarge isolated conductive objects into a coulombmeter.Destructive test.Cant test insulators this way.C_+_Q = CV/sundae_mengDirect Measurement of ChargeGRDirect Measurement of ChargeOther objects (charged

25、 insulators) must be placed in a Faraday enclosure that is connected to a coulombmeter.+_/sundae_mengDirect Measurement of ChargeOtDirect Measurement of ChargeIt is challenging to place object into a Faraday enclosure without adding or subtracting charge.Measuring charge using these direct methods m

26、ay be impractical. (Objects may be too large to place into a Faraday enclosure or not removable.)+_/sundae_mengDirect Measurement of ChargeItMeasuring Voltages on Isolated Conductors0000GROUNDFamiliar test equipment, such as digital voltmeters and oscilloscopes, cannot be used to characterize electr

27、ostatic charges.Contacting charged conductive objects quickly discharges the object.Contacting insulators discharges the contact point and doesnt measure the un-contacted surface._/sundae_mengMeasuring Voltages on IsolatedContacting ElectrometersVery high input impedance.GROUNDMinor loading of the c

28、harged conductor.Okay for measuring isolated conductors. Doesnt work for insulatorsC_+_/sundae_mengContacting ElectrometersVery hGROUNDVoltage followerMinimal loading of the charged conductorStill cant measure an insulatorC+_Contacting Electrometers/sundae_mengGROUNDVoltage followerMinimal Propertie

29、s of Charged ObjectsWe often evaluate a charged object indirectly by evaluating its electric field.Instruments that sense electric fields includeElectrostatic FieldmetersElectrostatic Voltmeters Non-contacting test method.+/sundae_mengProperties of Charged ObjectsWFieldmetersFieldmeters were origina

30、lly used to measure large objects.Measuring in a uniform electric field is desired.Point-to-point or point-to-plane measurements yield different measurement results./sundae_mengFieldmetersFieldmeters were orFieldmetersElectrostatic fieldmeters measure the field strength associated with a charge.The

31、unit of measure is the volt/meter (or some other convenient distance).Indicates the presence and approximate level of charge.Usually hand-heldBest suited for making general auditsCost-effective for measuring voltages above 3kV./sundae_mengFieldmetersElectrostatic fieldFieldmetersFieldmeters do not r

32、esolve low voltages.Fieldmeter measurements vary significantly with distance from the charged object.Fieldmeters do not resolve small surface areas. Two common types of fieldmeters areInduction FieldmetersChopper-Stabilized Fieldmeters/sundae_mengFieldmetersFieldmeters do not Simplest type of fieldm

33、eterNo system to improve drift and instabilityWont operate reliably in the presence of ionizationFieldmeters are grounded instruments and modify the data.Induction Fieldmeters/sundae_mengSimplest type of fieldmeterIndChopper-Stabilized FieldmetersDo operate in the presence of ionizationFeedback syst

34、ems to improve drift and instability performanceStill require a fixed spacing/sundae_mengChopper-Stabilized FieldmetersElectrostatic VoltmetersElectrostatic voltmeters use voltage feedback to null the electric field between the surface under test and the voltmeter probe.Also known as voltage followe

35、r or electrometerHigh degree of accuracy that is independent of the distance from the charge.Electrostatic voltmeters generally provide a better approximation of the charge level as compared to fieldmeters, and are better suited for making accurate and repeatable measurements./sundae_mengElectrostat

36、ic VoltmetersElectrElectrostatic VoltmetersThe sensor can be placed very close to the charged surface without arc-over.The sensor can resolve small surface areas. Very free of drift and environmental instability. Well suited for fixed installation in equipment. Not a grounded probePresence of high v

37、oltage on the reference surfaceWorks in ionization because they are chopper-stabilized/sundae_mengElectrostatic VoltmetersThe seAC-Feedback VoltmeterAC-feedback electrostatic voltmeters are part fieldmeter and part electrostatic voltmeter- a hybrid instrument with some characteristics of fieldmeters

38、 and some characteristics of electrostatic voltmeters.AC-feedback electrostatic voltmeters sense electric field and sense capacitance (distance) changes between the surface under test and the probe to indicate surface voltage even if the distance changes.Spacing independent accuracy of electrostatic

39、 voltmeters.Resolve small surface areas./sundae_mengAC-Feedback VoltmeterAC-feedbaAC Feedback Electrostatic Voltmeter/sundae_mengAC Feedback Electrostatic VoltAC Feedback Electrostatic VoltmeterAlso known as a spacing compensated fieldmeter, spot meterHow it is like a voltmeterHow it is like a field

40、meter Reports surface voltageLow costSpacing independent accuracyA grounded instrumentResolves small objectsArc over if used too close Good stability and drift performance/sundae_mengAC Feedback Electrostatic VoltComparisonsVoltmetersNot cost effective above 3kVExcellent spatial resolutionIntended f

41、or close spacing, measuring small objectsNot grounded Spacing independentaccuracyLow driftAC-FeedbackCost effective above 3 kVGood spatial resolutionGood at close spacings, measuring small objectsGroundedSpacing independent accuracyLow driftFieldmetersCost effective above 3 kVLow spatial resolutionI

42、ntended for wide spacing, measure large objectsGrounded/sundae_mengComparisonsVoltmetersAC-FeedbaUsing Voltmeters and Fieldmetersd4d - 5dAs electrostatic voltmeters can be operated close to a charged surface without fear of arc-over, they can resolve smaller surface areas.Extraneous fields can negat

43、e the whole notion of spatial resolution./sundae_mengUsing Voltmeters and FieldmeteUsing Voltmeters and Fieldmeters_ _ _ _ _ _+ + + + + +Insulators do not have uniform charge distribution.As charge density is non- uniform, surface potentials are non-uniform.What is measured is nebulous. Provides a f

44、igure of merit./sundae_mengUsing Voltmeters and FieldmeteAuditingHand-held meters are particularly useful for auditing.Grounding is important, especially for battery-operated instruments. Charge up objects of interest and see if they retain charge./sundae_mengAuditingHand-held meters are pDiagnostics and Continous MonitoringHand-held instruments are cumbersome for monitoring inside of process equipment, but many do have elec