DELL-Dye-and-Pry-Procedure

DellControlledPrintDyeandPryFailureAnalysisProcedureNumber:REL0164Revision:A00Engineers/Owners:DellReliabilityOrganization&Component/MaterialsFailureAnalysisLabDELLCONFIDENTIALTHISITEMISTHEPROPERTYOFDELLCORPORATION,AUSTIN,TEXASANDCONTAINSCONFIDENTIALANDTRADESECRETINFORMATION.THISITEMMAYNOTBETRANSFERREDFROMTHECUSTODYOFDELLCOMPUTERCORP.,ANDTHENONLYBYWAYOFLOANFORLIMITEDPURPOSES.ITMUSTNOTBEREPRODUCEDINWHOLEORINPARTSANDMUSTBERETURNEDTODELLCOMPUTERCORP.UPONREQUESTANDINALLEVENTSUPONCOMPLETIONOFTHEPURPOSEOFTHELOAN.NEITHERTHISITEMNORTHEINFORMATIONITCONTAINSMAYBEUSEDBYORDISCLOSEDTOPERSONSNOTHAVINGANEEDFORSUCHUSEORDISCLOSURECONSISTENTWITHTHEPURPOSEOFTHELOANWITHOUTTHEPRIORWRITTENCONSENTOFDELLCOMPUTERCORPORATION.–DyeandPryRev.A002of4DyeandPryProcedure1.PurposeThepurposeofthisdocumentistodescribeindetailtheDyeandPryprocedurethatisrequiredtobeusedonproductsevaluatedforDell.ModificationstothisprocedureareacceptableifsuchmodificationsaresharedwithDellandapproved.2.MinimumRequirements1.Machinist’sdye(recommendationisRedSteelDykem).2.Vacuumpumpandchamber(typicallyamechanicalpumpandbelljar).3.Stereomicroscopewithdigitalcamera4.Bakingovencapableof100C5.Abilitytosectionoutdesiredcomponentsfromboardwithoutexertingexcessivestressonthesolderjoints.6.Tooltoprythecomponentfromtheboard.7.Fluxcleaningsolvent.8.Trainedoperators.3.Procedure1.Identifycomponentstobe“DyeandPry”evaluated(consulttestplan).2.Sectionoutthedesiredcomponentleavingabout1.5to2inchesofboardaroundthepart.3.CleananyfluxresiduefromaroundtheBGAsolderbumpsusingasolvent(recommendusingaFluxRemoverspray-Isopropylalcoholaloneisnotacceptable).Removinganyfluxresiduesandotherparticles/oilsenablesthedyetomoreeasilypenetratethefractures.FailuretocompletelyremovefluxfromaroundtheBGAbumpsmaypreventinkpenetrationandgivefalseindicationsofagoodsolderjoint.4.Rinsewellwithwater(followedbyisopropylalcoholifdesired).Allowtocompletelydry.5.Immersethesectionedsampleinthedye(typicallyinasmalltray).6.Placethetrayandsectionedsampleintoavacuumchamber.Drawavacuumfor3to4minutes.Partiallyventandreapplyvacuumtothechamberafewtimestoaidindyepenetration.7.Turnoffvacuumpumpandleavethesampleinthedyeforseveralminutesundervacuum.8.Ventanyremainingvacuumandremovesample.Allowtheexcessdyetodrainoffthesample.9.Drythesampleinanovenbybakingat100°Cforupto30minutesdependingontheamountofdyeunderandaroundthedevice.Thedyemustbecompletelydried.Wetdyecansmearduringcomponentremovalresultinginfalseconclusions.Confidential05/18/2004ReliabilityFailureAnalysisProcedure–DyeandPryRev.A003of410.Followingremovalfromtheoven,allowtheparttocool.11.Thecomponentisthenmechanicallyremoved.Itcanbepriedoffwithachiselbutthismaydamagebumpsontheouteroneortworows.Theboardcanalsoberepeatedlyflexeduntilthedevice“pops”off.12.Afterthecomponentisremoved,theboardandpartaretobeexamined.Fracturedwettingpadsurfacesoneithertheboardorthecomponentwillbedyedred.13.Takephotosofdyedregionsandplotresultsinamatrixchart.Immerseindyeandplaceinvacuum.Ensuredyeiscompletelydry.Removecomponentbypryingor,removecomponentbytwisting.PhotosfromUniversalInstruments.Confidential05/18/2004ReliabilityFailureAnalysisProcedure–DyeandPryRev.A004of4Confidential05/18/2004Cracked/openpriortotestingPartiallycrackedbutstillconductivepriortotestingPWBExampleofsolderjointsaftercomponentremoval.ExampleofadyeandprymatrixmapwhichrevealsthelocationofthefracturewhencomponentisremovedfromthePCB.Asimilarmapisrequiredthatshowsthemagnitudeoftheinkpenetrationforeachsolderball(25%,50%,75%,100%).