bluech 发表于 2007-7-1 08:36:23

Package-related Failure Mechanisms and Attributes

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admin 发表于 2007-7-1 09:40:58

Package-relatedFailureMechanismsandAttributes

----------BallLifting
Balllifting,isthedetachmentofaballbondfromthebondpadofasemiconductordevice.
Seeseparatearticleonballlifting.
BondShorting
BondShortingisthepresenceofanunintendedelectricalconnectionbetweentwobonds.Theelectricalconnectionmaybeintheformofbondstouchingeachother,orstrayconductivematerialsbridgingonebondtoanother.Bondplacementproblemsinvolvingadjacentwedgebondswithlongtailsinadiewithtightly-packedbondpadsarethemostcommonformoftouchingbonds.
Designrulesforbondpadsizeandspacing,bondsize,bondposition,andbonddeformationcaneasilypreventtouchingbonds.Dieattachmaterialthataccidentallyfallsordripsonthediesurface,orreachitinwhateverway,canbridgeonebondtoanother.Straywiresthatsomehowgetintohermeticpackagescanalsobridgeonebondtoanother.Eutecticflakesorballsfromhighlyoxidizedeutecticdieattachmaterialcangetlooseinsidethepackageandlikewiseactasbridgesbetweenbonds.Aluminumsqueeze-outsaroundthewedgebondscanalsogetlooseandshortbonds.
BrandFailureAttributes
Poormarkabilityistheconditionwhereinthepackageisdifficultorimpossibletomarkorbrandcorrectlyand/orthemarkorbrandonthepackageexhibitsinsufficientpermanence.Inkmarkabilityproblemsareoftenduetotheinabilityoftheinktoadheretothesurfaceofthepackage.Lasermarkabilityproblemsareoftenduetoimproperbrandingequipmentset-up,butmaysometimesbeduetotexturalproblemsonthesurfaceofthepackageaswell.
Pooradhesionofinkmarksorbrandsonthepackageisusuallycausedbythepresenceofathinfilmorlayerofforeignmaterialonthepackagesurface.Forinstance,packageswithexcessiveamountsofmoldreleaseagentontheirsurfacesarelikelytoexhibitpoormarkability.Itmayalsobeduetotheuseofanincorrect,incompatible,orexpiredink.
Poorlasermarkabilityisusuallycausedbywronglaserbrandingsettings.Packageswithtexturalproblemsordefectsmaylikewiseexhibitpoorcontrastafterlasermarking.Forexample,reworkedpackagesthathaveundergonesandblastinggenerallyexhibitillegiblemarks.
Contamination,External
Externalcontaminationisthepresenceofaforeignmaterial,whetherattachedorunattached,anywhereontheexternalportionsofthepackageandleads.Thecriteriaforrejectingexternalcontaminationdependsonitslocation,extent,andcomposition.Somecontaminantsarerejectedbecauseitresultsincosmeticfailure,whileothersarerejectedbecauseofthereliabilityriskinvolved,mainlywithregardtoleadcsolderabilityissues,aswellaselectricalleakabetweenpins

tmbob 发表于 2007-9-1 21:50:18

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hmconline 发表于 2008-12-5 21:04:26

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Asia_wX96s 发表于 2021-5-10 16:32:20

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