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1、CSPDevicesReplacingProcedureCSPReplacing更换CSP•1)CSPdeviceisnotreworkable.OnceCSPonboardisprovedtofail,thatunitmustbereplacedbyanewunit.•CSP封装器件不可以重新植球.焊到板上后一旦发现器件失效,必须用新料更换.•2)FailedCSPRemoval:TodesolderthefailedCSPunit,itcouldbedoneineitherBGAreworkstationorbymanuallytouseahotairgun.•将失效的CSP器件
2、从板子上焊下来,可以在BGA重工台上操作,或用热风枪操作.CSPReplacing更换CSP•3)IfthereplacedunitisforFA,metaltweezersarenotallowedtodirectlypickofftheunit.Themetaltweezerstipsmustwrappedbyhightemperaturetape,toavoidtheunittobephysicallydamaged.HightemperatureplastictweezersorbambootweezersarerecommendedtobeusedforCSPpickup.
3、•如果要焊下来的器件是要做失效分析的,千万不能用金属镊子直接夹取CSP,这样会容易造成CSP损件,导致无法做失效分析.推荐使用耐高温塑料镊子或竹子镊子.或在金属镊子的尖上缠上高温胶带.CSPReplacing更换CSP•4)AfterthefailedCSPisremoved,usesolderirontocleanthePCBpads.Abitsolderpasteremainsonpadshelpgetbettersolderability.Solder-wickisnotrecommendedtouse.Solder-wickwillabsorballthesolder,nog
4、oodforsolderability.•失效的CSP焊掉后,用电烙铁将焊盘清理拓平.注意焊盘间不允许有连锡.少许残留焊锡有利于焊接.不建议用吸锡丝.吸锡丝会把焊锡吸干净,不利于焊接.CSPReplacing更换CSP•5)Useabrushtoapplyabitoffluxpasteonthecleanedpads.Noneedtoprintsolderpaste.•用毛笔或刷子蘸一点松香膏,在PCB焊盘上抹上薄薄的一层松香膏,不用太多.不需要印焊锡膏在焊盘上面.•6)Usenon-metaltweezerstopickonefreshCSPandmountitontoPCB,ma
5、kesuretheunitisincorrectorientationandwellaligned.•用非金属镊子取一粒新的CSP,放到PCB位置上,注意要对好位置和器件的正确方向.CSPReplacing更换CSP•7)ThenextstepistosoldertheCSPunit.ThiscanbedoneeitheronBGAreworkstationormanuallybyhotairgun.NormallycustomersdefinewhichwaytosolderCSP.SomecustomersspecifytouseonlyBGAreworkstationtosol
6、derCSP,andsomecustomersallowusinghotairgun.Bothmethodscangetgoodsolderqualityifsolderingincorrectway.•下一步是焊接CSP,可以在可以在BGA重工台上操作,或用热风枪操作.一般来说板子的客户会规定用哪一种方法来焊.有些客户规定只能用BGA重工台,有些客户也允许用热风枪.无论用哪种方法,只要操作得当,都能得到良好的焊接效果.CSPReplacing更换CSP•8)Usehotairguntosolder:Settheairtemperaturetobearound425degreeC(f
7、orleadfreedevices)or400degreeC(foreutecticdevices).Atbeginningtheairflowmustbeadjustedto0(otherwisetheCSPunitwillbeblownaway,setto0thereisstillhotaircomesout).ApproachthenozzledowntoCSPfromrighttop,blowhotairatheightofabout5mmabov
