欢迎来到天天文库
浏览记录
ID:33837273
大小:200.20 KB
页数:16页
时间:2019-02-28
《Wire Bonding.pdf》由会员上传分享,免费在线阅读,更多相关内容在学术论文-天天文库。
1、ChapterA:WireBonding2Level2.Conclusionsandguideline2.1WirebondingtechniquesTherearetwobasicwirebondingtechniquesthatareusedinthermocompression(T/C),thermosonic(T/S)orultrasonic(U/S)bondingprocess:ballbondingandwedgebonding.Approximately93%ofallsemiconductorpackagesaremanufacturedusing
2、ballbondingmethod,whilewedgebondingisusedtoproduceabout5%ofallassembledpackages.2.1.1BallbondingInthistechnique,wireispassedthroughahollowcapillary,andanelectronic-flame-offsystem(EFO)isusedtomeltasmallportionofthewireextendingbeneaththecapillary.Thesurfacetensionofthemoltenmetalfroma
3、sphericalshape,orball,asthewirematerialsolidifies.Theballispressedtothebondingpadonthediewithsufficientforcetocauseplasticdeformationandatomicinterdiffusionofthewireandtheunderlyingmetallization,whichensuretheintimatecontactbetweenthetwometalsurfacesandformthefirstbond(ballbond).Theca
4、pillaryisthenraisedandrepositionedoverthesecondbondsiteonthesubstrate,apreciselyshapedwireconnectioncalledawireloopisthuscreatedasthewiregoes.Deformingthewireagainstthebondingpadmakesthesecondbond(wedgebondorstitchbond),havingacrescentorfishtailshapemadebytheimprintofthecapillary’sout
5、ergeometry.Thenthewireclampisclosed,andthecapillaryascendsonceagain,breakingthewirejustabovethewedge,anexactwirelengthisleftforEFOtoformanewballtobeginbondingthenextwire.Ballbondingisgenerallyusedinthermocompression(T/C)oroothermosonicbonding(T/S)process.Thistechniquerequiresahightemp
6、eratureragingfrom100Cto500Cdependingonbondingprocess.Heatisgeneratedduringthemanufacturingprocesseitherbyaheatedcapillaryfeedingthewireorbyaheatedpedestalonwhichtheassemblyisplacedorbybothdependingonthebondingpurposeandmaterials.Relativelysmallgoldwire(<75mm)ismostlyusedinthistechniqu
7、ebecauseofitseasydeformationunderpressureatelevatedtemperature,itsresistancetooxideformation,anditsballformabilityduringaflame-offorelectronicdischargecuttingprocess.Ballbondingisgenerallyusedinapplicationwherethepadpitchisgreaterthan100mm.However,theapplicationofthepitcheswith50mmhas
8、beenr
此文档下载收益归作者所有