BGA返修和工作原理介紹

BGA返修和工作原理介紹第1頁/共26頁BGARepair:abetterunderstandingcanreducefears,reducecosts,andguaranteeprocesscontrol第2頁/共26頁Densityandperformancerequirements

DrivingICpackingtowardthesizeofthebaredieTrendsinFlipChipuseTheGlobalTrendtoAreaArrayPackages第3頁/共26頁BGA,CSP,FlipChip:StructuralDesigns第4頁/共26頁BGAProduction-

CollapsibleandNon-collapsibleAreaArrayPackagesIngeneral,eutecticsolderballs(Sn63Pb37)arealwaysusedforareaarraypackagesexceptinthecasewheretheweightofthecomponentisgreaterthanthesurfacetensionofthemoltenballsduringreflow.ACBGA(ceramicBGA)isatypicalexampleofacomponentthatcouldnotbe“carried“bythesurfacetensionofthesolderballsduringthereflowprocess.Inthiscase,ahighmeltball,forexamplePb90Sn10,isusedbecauseitwillremainsolidduringthenormalreflowprocess.BallComparisonPhotosComparisonofInstalledPBGAtoaCBGATheabovefiguresdetailthedifferentwettingzones,andwettinganglesbetweenaPBGAandCBGAandtheirrespectivejoints.第5頁/共26頁TheSolderingProcess-TheIntermetallicBondandits

RelationtoReflowTemperatureTheheartofthesolderjointSource:R.J.Kleinwassink,Solderingintheelectronics

Asolderjointhastwokeypurposesinthejoiningoftwomaterials:

1.Anelectricalconnection 2.AlastingmechanicalconnectionThelastingmechanicalconnectioncanonlybeachievedwhentin-lead(solder)isintroducedtoformalastingintermetallicbondbetweentheleadandlandandbothareheatedtoapprox.30°Cabovethemeltingpointofsolder.Scanningelectronmicrograph(SEM)offracturedintermetalliclayersofasolderjoint.Cu3Sn(e-phase)andCu6Sn5(n-phase)makeuptheintermetalliclayers.第6頁/共26頁TypicalReflowProfilesInfrared-soldering.Temperature/time-profile(lead-temperature).

Full-line:typicalprocess/dotted-line:processlimitsTemperature-timecurvesobtainedinahot-aircirculationoven.Source:R.J.Klein-WassinkReflowsolderprofileCECC00802:CECCStandardMethodfortheSpecificationofSurfaceMountingComponents(SMDs)ofAssessedQuality.第7頁/共26頁A.BGAsolderball(Sn63PB37)placedonpadbeforereflowprocessbegins.Stand-offheightis,forexample,1.0mm(ballshapeundercomponentisperfectlyspherical,surfaceissmoothanddull).

B.Reflowprocessbeginsuntilmeltingpointofsolderballisreached(183°C),gravityactsoncomponentandcausesaninitialorsingledrop:Stand-offheightis0.8mm(ballshapeisverticallyelongated,surfaceisroughandmatt).C.Peaktemperatureisreachedinthereflowprocessallowingforcompleteandproperwettingofentirepad.Asecondordoubledropoccurs:stand-offheightis

0.5mm(ballshapeishorizontallypressedorsomewhatelliptical,surfaceissmoothandshiny).BGAProduction-

TypicalPhysicalEffectsduringaReflowProcessThetypicalphysicaleffectsduringthereflowprocessofaPBGAaregraphicallyshowninthefiguresbelowwithregardstothestand-offheightandwettingangle.1mmAConditionA

BeforeReflowBeginsB0.8mmConditionB

AtSolderMeltPoint0.5mmCConditionC

AtProperPeakTemperature第8頁/共26頁DoubleDropEffectbyBGA/CSP/FlipChip(Sn63Pb37Balls)1stDrop

2ndDropGraphicdepictsanon-soldermaskdefined(NSMD)padNote:LifecycletestresultsshowthatNSMDpadonbothboardandpackagegivesuperiorperformancetowhensoldermaskdefined(SMD)padsareused.

Source:ReliabilityofBGAPackagesinanAutomotiveEnvironment,RogerR?rgren,Per-ErikTegehallandPerCarlsson,IVF-TheSwedishInstituteofProductionEngineeringResearch,www.ivf.se第9頁/共26頁BGADoubleDropEffectDocumentedbyPhilipsCFTSource:BGAJointFormation,JanKolsters,PhilipsCFT,Eindhoven,Netherlands,May2000VideoclipofBGAjointformationrevealingthedoubledropeffect.ThevideowasgeneratedusingtheERSASCOPEInspectionSystem.Clickheretobeginvideo第10頁/共26頁Across-sectionofaPBGA225afteraproperreflowprocessrevealsthecompletewettingtothepadandtheproperwettingangleofthefluxresidue.

Cross-sectionofproperDoubleDropPBGACross-sectionofPBGA225afterSoldering第11頁/共26頁BGASelf-AlignmentEffectTheself-alignmenteffectasthesolderballsgointoreflow第12頁/共26頁BGASelf-AlignmentEffectDocumentedbyPhilipsCFTSource:BGAJointFormation,JanKolsters,PhilipsCFT,Eindhoven,Netherlands,May2000VideoclipofBGAjointformationrevealingtheself-alignmenteffect.ThevideowasgeneratedusingtheERSASCOPEInspectionSystem.Clickheretobeginvideo第13頁/共26頁BGARepair:HotAirSystems第14頁/共26頁BGARepair:HotAirvs.IRHeatdistributionacrosssurfaceofBGA-

convectionanddarkIR第15頁/共26頁TypicalBGAProblems:X-rayInspectionDeformedballs,i.e.non-spherical

Missingball,solderbridging,

Non-uniformsolderquantity

VoidsMisregistration第16頁/共26頁CBGAsolderedtoPCBX-rayimageofCBGAaftersolderingERSASCOPEimageofCBGA.CrackingzoneisvisibleX-rayimageofPBGA225:

AandBshowmistakesbutareunclearofsourceA.ERSASCOPErevealsfluxresiduebridgewithconductiveparticlesB.ERSASCOPEshowsincompletesoldermeltofpaste.BATypicalBGAProblems:VisualInspectionandX-raycombined第17頁/共26頁DarkIRvs.lightIRforPCB-reflowapplicationsWavelengthrangesofsomeradiationsourcesandtheirpositioninthespectrumofelectromagneticwaves.ThetopandbottomERSAdarkIRradiatorsaremediumwavelength(2-8μm),whichhasbeenproventohavetheoptimalabsorption/reflectionradiobetweenlightanddarkcolors.Thecomponentbody,substrate,andleadsaresafelyandevenlyheated,therebyreducinganyriskofdamageduringthereflowprocess.第18頁/共26頁ERSADarkIRBGARepair:UniformHeatDistributionHeatdistributionacrosssurfaceofBGA169第19頁/共26頁BGARepair:ProductionlikeresultswithIR500ASource:FraunhoferInstitutISIT,Itzehoe,Germany第20頁/共26頁ReworkEquipmentPurchaseDecisionFlowChart1.Quality-ResultsO.K.?2.Repeatability-User-Friendly?3.Flexibility-Chips,Plastic,BGA,PTH,...?

-InitialInvestment?

-CycleTime?

-Nozzles,etc.?

-SpareParts,e.g.heaters?4.ReturnonInvest-OperationalCosts

?第21頁/共26頁第22頁/共26頁P(yáng)L500A:OpticalBGA/SMDPlacementSystemMotorizedZ-axis,

Zoom,andFocus

SplitOptics

AutoZoom

Pre-sets

AutoVac

Pick-n-Place

TwoCameraInputs/AutoSwitch

Standaloneorfullyintegrated第23頁/共26頁μBGA,CSP,FlipChipPrecisionPlacementandReflow第24頁/共26頁ERSAIR500AInternationalUsersListABBADIAGFA

AIRSYSNavigation

ArabBritischDynamicsCo.

ASGLuftfahrttechnik

BertelsmannBlaupunktBORAQBoschBritishAerospaceCellstarCOMPAQ

ComtechData-FaxDIALOGSemiconductorDigitrondaAmazonia

EFACECEFOREOyEIA-ElectronicaAvionicos

ELABOGmbHEricssonComponents

EricssonRadioSystems

FASTLinkFischerElektronmechanik

FraunhoferInstitutGallyasS.A.

GLOBALNET

GrundigHCL

HeidelbergerDruckmaschinen

I.S.T.-Instituto

IBM

Insti