《COB制程》PPT课件

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1、Date:08/30/2000PreparedbyAndyGanCOBInternalTrainingWhatisCOB?CHIPONBOARDCOBFlowChart1CleanCOB2DropRedEpoxyResin3MountingChip4Bake8Encapsulate7FunctionTest6ProcessTest5WireBonding9FunctionTest10Bake11FunctionTest12ProcessTestCOBProcedure1.CleanPCBCleanspotswhichex

2、istsinPCBtoassuredroppingeasily.COBProcedure2.DropRedEpoxyResinUseinfixingchip,quantityofglueshallbeexactandwellmixed.COBProcedure3.MountingChipUsevacuumpentofixchipinPCB,noticepolarityandshiftingangle(<5degree).Theairpressureisdifferentfromeachchip.Vendorwilladj

3、ustairpressuretotheminimumatfirst,thenraiseitslowlytofittherequirement.4.BakeSolidifyepoxyresinbybake-box,fixchip.COBProcedure5.WirebondingConnectweldingdotofchipandtin-foilinPCBbyaluminumline.Effectingfactorofwirebonding:a.Wirediameterb.Angleofweldingc.Weldingdo

4、td.TensileforceofaluminumlineEffectingfactorofwirebondinga.WirediameterAluminumlinehasC.C.C,K.SandTANAKA,anddiameterinclude1.0miland1.25mil.Select1.0milifdistanceofweldingdotislittleandthicknessofPCBisbig.Select1.25milifdistancebetweenweldingdotofchipandtin-foili

5、nPCB,thisalsooughttofittheconditionthatthedistanceofweldingdotislargeandsmallthicknessinPCB.Effectingfactorofwirebondingb.Angleofweldingmustbelessthan45degreeCorrectiveactioniftheangleislargethan45degree1.Rearrangethepositionofgoldenfinger.2.Prolongfingerwhichbei

6、n“2”.Effectingfactorofwirebondingc.WeldingdotMinimumsizeofgoldenfingeris6milandminimumofdistanceis6miltoo.Notice:TheaboveweldingdotminimumsizeisaccuracyofFR4glassfibersheet.Therequirementcan’tberealizedifitisCAM3cardboard.Effectingfactorofwirebondingd.Tensileforc

7、eofaluminumline(1)PCBhasn’tbeencleanedcompleteItwillbedifficulttoweldaluminumlineifyoudon’tremovethespotfromPCB.(2)ParameterofmachinesetupnotcorrectlyNewmodel’smachineparameterissetupbytechnicalpersonnelaccordingtotheirexperience.Theyhavetoobservetheworkingcondit

8、ion,analyzetherootcauseofdefect,andconfirmtheparameter.(3)Materialfactor*Widthofgoldenfingeristoolittle,weldingshift,resultintensileforcereduce.*Surfaceofgolde