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1 Moisture-SensitivityClassificationofFlan ge-MountedPackagesatTexasInstrumentsAppl icationReportLiteratureNumber:SLZA002 September20072 SLZA002 September2007 SubmitDocumentationFeedback1 IntroductionApplicationReportSLZA002 (MSL)offlange-mountedpackagesisperformed usingtheJointIndustryStandardIPC/J-STD-0 20 Cguidelinesforsurfacemounttechnology(SMT ) ,QFPorTSOP;flange-mountedandSMTpackagesw ithexposeddiepaddle(seeFigure1), PackageExposed Die Paddle PackageDie paddle/Die size ratioBond Line ThicknessSmaller Die PaddleLarge Die PaddleThick Bond Line ThicknessThin Bond Line ThicknessDie Paddle FinishIncrease in Die Paddle ,leadframefinish,materialselection,andas semblyprocessvariations(bondlinethicknes s,curingprofile,filletheight,etc). ,delaminationatthisinterfaceareacouldbea majorreliabilityproblem, , , ,thesilicondie,andthemoldcompound, ( 65to150 C) (wirestitchlocationisalsoafactor). hard connectedtothediepaddle, (MSL)offlange- : (beforesubmittingtheunitstotheactualtest ).

2 +5/-0 FinalAcousticMicroscopy(CSAM). :Levelofdelaminationisestimatedbasedonth eamountof red colorseenonthescanningacousticmicroscopy (SAM). ,toevaluatetheimpactofdelaminationondevi cereliability, ,historicalgenericdataanalysis, , ( 65 C/150 C,or 55 C/125 C,or 40 C/125 C). C/85% ,takeasampleoffivestressedunitsthatpasse dfunctionaltest,doaSAManalysisonthemtome asurethedelaminationarea, (intermetallicdegradation,corrosion,etc) , ,TIallowsthistypeofdelamination, , , ,eliminatetop-sidediedelamination, (BSB),studstitchbond(SSB),andreversestan d-offstitchbond(RSSB), ,alloftheseoptionsarecompatiblewithtoday ,tolowerthestressonthestitch,areselectiv eplatingonthediepad,addingagroundringtoi mprovemoldlockingaroundthestitch,addingm echanicalmoldlockingfeaturesonthediepads uchasgroovesordimples,bondingthestitchto araisedfeaturesuchasatiebar,orusingasimp lerapproachandincreasingtheMSLlevel(2 3,etc). (moldcompound/dieattach/leadframefinish) ,TO252,SOT223packages,duetoitsunbalanced construction,areverysensitivetomoisturei ngression, (TIcodeKTT), , , , ,theTIdeviceshavezeroorpartialdelaminati onwhereasalltheothersupplierdeviceshave1 00% , , , open.

3 Noneoftheanalyzeddevicesweresubmittedfor reliabilitytestingduetoinsufficientsampl esize,butfromthiscompetitiveanalysis, ,duetopackageconstruction,costpressures, andreflowtemperaturerequirements, , ,alongwiththeappropriateMSLrating, September2007 TexasInstruments13 SubmitDocumentationFeedbackIMPORTANTNOTI CET exasInstrumentsIncorporatedanditssubsidi aries(TI)reservetherighttomakecorrection s,modifications,enhancements,improvement s, , , ,eitherexpressorimplied,isgrantedunderan yTIpatentright,copyright,maskworkright,o rotherTIintellectualpropertyrightrelatin gtoanycombination,machine, , ,conditions,limitations, (suchaslifesupport)whereafailureoftheTIp roductwouldreasonablybeexpectedtocausese verepersonalinjuryordeath, ,andacknowledgeandagreethattheyaresolely responsibleforalllegal,regulatoryandsafe ty-relatedrequirementsconcerningtheirpro ductsandanyuseofTIproductsinsuchsafety-c riticalapplications, , "enhancedplastic." 'srisk, ,iftheyuseanynon-designatedproductsinaut omotiveapplications, :TexasInstruments,PostOfficeBox655303,Da llas,Texas75265 Copyright 2007,TexasInstrumentsIncorporat