IBM-Quality-and-Reliability

ASICProductsApplicationNoteQualityandReliabilityRevision3SA14-2280-03IBMNotices:Beforeusingthisinformationandtheproductitsupports,besuretoreadthegeneralinformationonthebackcoverofthisapplicationnote.Trademarks:ThefollowingaretrademarksorregisteredtrademarksofInternationalBusinessMachinesCorporationintheUnitedStates,orothercountries,orboth:IBMIBMLogoOthercompany,product,orservicenamesmaybetrademarksorservicemarksofothers.©InternationalBusinessMachinesCorporation1999.Allrightsreserved.IBMASICProductsApplicationNoteQualityandReliability12/8/99Revision3AbstractPage1AbstractSuperiorintegratedcircuitdevicereliabilityisattainedwhenitisanintegralpartofprocessdevelopment,design,andmanufacturing.ThisapplicationnotedescribesthemethodologyusedbyIBMtoachieverobustASICdesignsbeforemarketintroduction,andtoensurehighqualityandreliabilityduringvolumeproduction.IntroductionThetypicaltimedistributionofreliabilityfailuresisdescribedbythe“bathtub”curveshowninFigure1.Thecurveisdividedintothreesegments:aninfantmortalityperiod,markedbyarapidlydecreasingfailurerate;astable,usefullifeperiod,wherethefailureratecontinuestodecrease;andaperiodofincreasingfailureraterepresentingtheonsetofproductwear-out.Infantmortalityandusefullifefailuresarecausedbydefectsintroducedduringthemanufacturingprocess.Defectivecomponentsareremovedbyefficientreliabilityscreens.Wear-outfailuresareavoidedbycarefultechnologydevelopmentandproductdesign,andbyusingeffectiveprocessmonitorsduringproduction.Figure1.BathtubCurveInfantMortality(failuresremovedbyburn-in)UsefulLifeWearout(wellbeyondnormalproductlife)Field-UseHoursPage2Revision3IBMReliabilityManagementSystem12/8/99ASICProductsApplicationNoteQualityandReliabilityIBMReliabilityManagementSystemReliabilityfailsareacombinationofthreeproblemtypes:wear-outmechanisms,whichshortenusefullife;systematicdefectscausedbyprocessvariationbeyondacceptablelimits;andrandomdefectscreatedbyprocessdeficiencies.IBMmanagesallthreeproblemtypesbyemphasizingreliabilityinalldesignproce-dures.Earlydesignandqualificationactivitieseliminatewear-outfailuremechanisms(suchashotcarriersandelectromigration)andestablishtechnologyandprocesslimitsthatminimizedesignsensitivitytomanu-facturingdefects.Processcontrolandtoolingimprovements,combinedwithefficientburn-inandMaverickscreens,providecontinuousdefectreduction.AttributesoftheIBMreliabilitymanagementsystemaresum-marizedinTable1.Table1.ReliabilityManagementSystemWear-outMechanisms:Technology“WeakPoints”Strategy:EliminatefromDesign•TechnologyDesign/Change•ChipDesignGroundRules•ApplicationSpecificationsSystematicDefects:ProcessMarginalitybeyondacceptablenormStrategy:ControlTechnologyProcess•TechnologyDesign•LayoutGroundRules•ProcessMonitorsRandomDefects:ProcessDeficienciesStrategy:ContinualDefectReduction•Technology/ToolingImprovements•ScreenOutResiduals•Wafer/ChipScreens•MaverickControls•High-EfficiencyBurn-InASICProductsApplicationNoteQualityandReliability12/8/99Revision3IBMQualificationProcessPage3IBMQualificationProcessAnoverviewoftheIBMqualificationprocess,fromtechnologyinceptiontofullproduction,isshowninTable2.Reliabilitymanagementbeginswiththestartofanewtechnology,whendesignmodelsaredevelopedandusedtoevaluatenewfeatures,andreliabilityteststructuresaredefined.Acceleratedtestsareperformedtoinvestigatepotentialwear-outmechanisms,includinghotcarriers,dielectricintegrity,ionicsandtemperaturestability,mechanicalstability,stress-inducedmetalvoiding,andelectromigration.Thetechnologyqualifica-tionprocess(T0,T1)establishesadequatecontrolofwear-outmechanisms.Stressresultsareutilizedtodefinethechipandtechnologydesigngroundrules,applicationspecificationlimits,andprocesscontrolsrequiredtoavoidwear-out.Waferscreenandburn-indesignrequirementsareverified.Uponsuccessfulcompletionofthetechnologyqualificationphase,earlycomponentsamplesaresubjectedtoafullseriesoftests(T2).Theseincludefunctionalityteststoevaluateelectricalperformanceandtodefinetestmargins,functionalandenvironmentalstressestomeasureproductreliability,mechanicalteststoeval-uatethepackagefitnessforuse,andteststoevaluateproductrobustnessagainstlatch-up,softerrors,andelectrostaticdischarge(ESD).Table2.IBMQualificationProcessT0:TechnologyDefinition•CriticalDesignPoints•ReliabilityTestVehicles•DesignModelsT1:TechnologyFeasibility•RulesforWear-outAvoidance•FormalTestStructureEvaluations•CriticalParameters/GroundRuleGenerationT2:ManufacturingFeasibility•Chip/PackageDesignRobustness•ProductReliabilityModels/MeasuredLevels•Burn-InStrategyVerification•DesignSystemCertificationSQ:Manufacturability•FabricatorProcessIntegrity,Repeatability•ProductMonitorsEstablishedProduction:ProductionMonitor•RoutingStresses/TestsversusTargets•MaverickControls•Line/FieldReturnsProgramPage4Revision3IBMQualificationProcess12/8/99ASICProductsApplicationNoteQualityandReliabilityFailuresreceivecompleteelectricalandphysicalanalysis.Rootcauseinformationisfedbacktotheappro-priateprocessanddesignengineeringareaswiththegoalofeliminatingallfailuremechanisms.Withnewtechnologies,productfunct