SMTdefectsandcountermeasureSMT缺陷及防范措施2025/6/241IdentifySMTdefectsIdentifytheSMTdefectsaccordingtoIPC-A-610(Rev:D)根據IPC-A-610(Rev:D)確定缺陷．

Thisstandardisacollectionofvisualqualityacceptabilityrequirementsforelectronicassemblies.IPC-A-610是關于電子組裝外觀質量驗收條件要求的文件．2025/6/242Majorcontributortodefects

缺陷的主要分布Source:MPM’sAuser’sguidetomorePreciseSMTprinting2025/6/243Knowthecommondefect

了解常見缺陷類型Analysizethepossiblecause

分析可能的原因Countermeasureforthedefects

基于以上原因采取的對策

LearningObjectives

學習目的2025/6/244?

Chip

components

standing

on

a

terminal

end

(tombstoning).片式元件末端翹起（墓碑）Tombstoning/立碑2025/6/245Countermeasure/對策Mechanism:Surfacetensionincomponentterminalisuneveninreflow.原理:在回流過程中零件兩末端的表面張力不均衡.1.Componentterminalheatdistributedunevenly零件兩末端受熱分布不均衡.Insufficientsoaktime:Reflowprofileoptimization.

保溫區時間太短:優化回流曲線參數.2.PCBPaddesignissue(thepadsdistanceistoobig):improvePCBpaddesign.PCB焊盤設計問題(焊盤間距太大):改善PCB焊盤設計.Tombstoning/立碑2025/6/246Countermeasure/對策

3.Componentterminaloxidizationorcontamination:SolderabilitytestifnecessaryandRTVthedefectmaterial.

元件末端氧化或者受污染:根據情況做可焊性實驗并且退還缺陷物料.4.Printingmisalignment:adjustprintingmachineparameters.絲印偏位:校正絲印機的參數.5.Placementmisalignment:OptimizetheP&Pmachineparameters.

貼片偏位:優化貼片機的參數.6.Stencilaperturedesignissue:studyandimprovetheaperturedesign.

鋼網開孔的設計問題:研究并且改善開孔設計.

Tombstoning/立碑2025/6/247?Asolderconnectionacrossconductorsthatwasjoined.焊錫在導體間非正常連接.?

Solder

has

bridged

to

adjacent

non-common

conductor

orcomponent.焊錫橋連到相鄰的非導體或元件.Solderbridge/橋聯2025/6/248Countermeasure/對策

1.Screenprintingissue/絲印問題:a)PasteheightoutofUCL:Adjusttheprintertocontrolthepasteheight.錫膏高度超出控制上線:校正絲印機,控制錫膏高度.b)Pasteprintingmisalignmentorbridging:Finetuneprintingmachine./錫膏印刷偏位或者橋聯:優化絲印機.c)Icicleprinting:Finetuneprintingmachineorchangetolowerviscositypaste.絲印拉尖:優化絲印機或者使用低粘性的錫膏.d)Solderpastecollapse:changetohigherviscositypaste./錫膏塌陷:使用高粘性的錫膏.e)Nonstandardstencilapertureopening:Studyandimprovetheaperture./不標準的鋼網開孔:研究并改善開孔.Solderbridge/橋聯Icicleprinting絲印拉尖Pastecollapse錫膏塌陷Bridging橋聯Misalignment印刷偏位2025/6/249Countermeasure/對策2.Pick&Placement/貼片a)Componentplacingmisalignment:FinetunetheP&Pmachine.元件貼片偏位:優化貼片機的參數.b)Highpressureforplacement:reducepressuretopropervalue.

貼片壓力過大:減少壓力到適當的參數.3.Wavesoldering/波峰焊a)Lowconveyorramp:Raisetheconveyorrampperactualstatus.傳送帶角度過小:根據實際情況加大傳送帶角度b)Lessfluxonboard:Increasethefluxsprayvolumeonboardbeforegoingthroughwavesoldering.板上的助焊劑較少:波峰焊接之前加大助焊劑的噴射量Solderbridge/

橋聯2025/6/2410Componentdamaged(Nicks,cracks,orstressfractures)/元件損壞Nicks,cracks,orstressfractures.缺口，裂紋，壓痕2025/6/2411Countermeasure/對策1.Rawmaterialdamaged:purgethebatchmaterial./來料損壞:清除這批來料.2.DamagedduringSMTprocess(Fixtureormachinetouchit):Investigateandtakecorrectiveactionsfornonstandardoperation.

在SMT流程中損壞(夾具和設備接觸):調查分析并且對不規范的操作作出矯正行動.3.Fastcoolingrateonreflowprocess:Controlthecoolingratetobelow4degreepersecond.

在回流過程中冷卻速率過快:控制冷卻速度使斜率保持在每秒4度以下.Typicalreflowprofile/回流曲線典例:PreheatstageSoakstageReflowstagePeaktemp.Cooldown<4oC/sComponentdamaged(Nicks,cracks,orstressfractures)/元件損壞2025/6/2412Misalignment偏位2025/6/2413Countermeasure/對策1.P&Pmachinefunctionunstable:FinetunetheP&Pmachine.

貼片機性能不穩定:優化貼片機性能參數.a)FinetuneX,Ydata/調整X,Y坐標b)Optimizepickandplacementparameters./校正吸料和貼片的參數.

2.Componentterminationoxidization:Solderabilitytestifnecessary.Purgethefailedmaterial/元件末端氧化:可焊性實驗,清除不合格的來料.

3.Operatortouchthecomponentpriortoreflow:Standardizetheoperatorhandling(documentcontrol)/在回流爐前目檢操作員碰到貼片元件:標準化操作員操作(文件控制)4.Airflowrateinthereflowovenissohighthatthecomponentsaremoved.回流爐內空氣流量太高以致吹偏了元件.Misalignment偏位2025/6/2414Componentleadlifted元件引腳翹高One

leadorseriesofleadsoncomponentisoutofalign-ment

and

fails

to

make

contact

with

the

land.元件一個或多個引腳變形不能與焊盤正常接觸．2025/6/2415Componentleadlifted元件引腳翹高Countermeasure/對策1.Componentleadbentbeforeplacement:Sortthedefectivepartandreturnittovendor.貼片前元件引腳變形:挑選出缺陷元件,退回供應商．2.Manualplacementtheloosepart:Inspectthepartbeforepassittoreflow.手放散料:回流前目檢．2025/6/2416Solderball錫珠Solderballsarespheresofsolderthatremainafterthesolderingprocess.Solderballsviolateminimumelectricalclearance.焊錫球是焊接后形成的呈球狀焊錫.

Solderfinesaretypicallysmallballsoftheoriginalsolderpastemetalscreensizethathavesplatteredaroundtheconnectionduringthereflowprocess.焊錫殘渣是在回流中形成的小的球狀或不規則狀焊錫球.2025/6/2417Solderball錫珠

Countermeasure/對策1.StencilAperturedonotfocustopad:improvestencilapertureopening.

鋼網開孔沒有對準焊盤中心:改善鋼網開孔.2.Printingmisalignment:Finetuneprintmachine.

絲印偏位:調整絲印機狀態.3.Excesspaste:Cpkcontrol.多錫:Cpk控制.4.DampPCB:BakethePCBbeforeloadingittoSMT.PCB焊盤受潮:SMT組裝流程之前烘烤PCB.6.Stencilpolluted:cleanthestencil.鋼網臟污:清洗鋼網.7.Profilerampupistoofast:Optimizereflowprofile.

回流曲線升溫速度過快:優化回流曲線.8.Pasteoxidized:exchangewithfreshsolderpaste.錫膏氧化:更換新錫膏.9.Chipwaveorsolderwaveheightistoohighcausedexcesssoldertotopside:adjustthewavesolderingheighttoproperlevel(wavesolder).

波峰高度設置的太高致使多余的焊錫到頂面:校正波峰焊設置到適當的高度

(波峰焊接).2025/6/2418Non-Wetting,Dewetting/虛焊，半潤濕

?

Solder

has

not

wetted

to

the

land

or

termination

where

solderisrequired.

虛焊:需要焊接的引腳焊盤不潤濕．?Solder

coverage

does

no

meet

requirements

for

the

termination

type.

?

Dewettingasaconditionresultswhenmoltensoldercoatsasurfaceandthenrecedestoleaveirregularly-shapedmoundsofsolderthatareseparatedbyareasthatarecoveredwithathinfilmofsolderandwiththebasismetalorsurfacefinishnotexposed.

半潤濕:熔化的焊錫浸潤表面后收縮,留下一焊錫薄層覆蓋部分區域,焊錫形狀不規則.2025/6/2419Non-Wetting,Dewetting/虛焊，半潤濕1.Poorsolderabilityofcomponentorpad./元件或焊盤可焊性太低Rootcause:a)OlddatecomponentorPCB./陳舊元件或PCB板b)ContaminationoroxidationoncomponentorPCB.元件或焊盤污染或氧化Action:Purgethematerialforfurtherdisposition.

/清除來料2.Thepasteoutofitslifetime:/錫膏超出有效期Scrapthelotpasteandreplaceitwithfreshone報廢有問題的錫膏更換新錫膏2025/6/2420Coldsolder/冷焊

?Incompletereflowofsolderpaste.焊錫回流不完全2025/6/2421Coldsolder/冷焊

Countermeasure/對策1.Peaktemperatureistooloworreflowtime(dwelltime)

isnotenough:Re-setuptheprofiletofulfillthepastespecorcustomerprovidedspec.requirement.回流峰值溫度太低或者回流時間不夠:重設溫度曲線圖.Typicalreflowprofile:/典型的回流曲線PreheatstageSoakstageReflowstagePeaktemp.Cooldown<4oC/s2025/6/2422Time時間Temp.溫度230°C250°Ctc1–smallSMDtc1–mediumSMDtc3–largeSMD20°C20°CTooHot!TooCold!Peak:230–250°CColdsolder/冷焊2025/6/2423Coldsolder/冷焊

Countermeasure/對策2.Thecomponentinsomelocationcoveredwithreflowpallet(Peaktemperatureistooloworreflowtime(dwelltime)

isnotenough):EnlargethepalletopenwindowforthedefectlocationstoreducetheΔT.某些元件位置被回流托盤遮擋造成該點峰值溫度太低或回流時間不足:

對缺陷位置放大托盤的開口從而減少溫差（ΔT）.

2025/6/2424Solderhole/錫洞

?Blowholes,pinholes,voids吹孔,針孔,空洞2025/6/2425Solderhole/錫洞

Countermeasure/對策1.Insufficientpreheat:Reflowprofileoptimize.預熱時間不足:優化回流曲線設置.2.Rampupistoofast:Re-setupthereflowprofiletomakeitoptimize.

升溫速率太快:重設回流曲線圖使之最優化.3.Excessfluxinsolderpaste:properlytoincreasepreheattimeandtemperature.

錫膏助焊劑含量過多:適當增加預熱時間和溫度值.4.DampPCB:BakethePCBbeforeloading

ittoSMT.

PCB受潮:SMT組裝前烘烤PCB板.5.Componentfeetoxidation:BakeitbeforeSMTorrequirevacuumpackingonincomingmaterial.元件腳氧化:烘烤或者來料真空包裝.6.Attachedfluxresidueoncomponentfoot:Sortoutthedefectpart.

元件腳有助焊劑殘渣:挑選出缺陷來料.

2025/6/2426DisturbedSolder/焊錫紊亂?Disturbed

solderjointcharacterizedbystresslinesfrommovementintheconnection.在冷卻時受外力影響,呈現紊亂痕跡的焊錫2025/6/2427DisturbedSolder/焊錫紊亂Countermeasure1.Optimizereflowsoldering

profileespeciallyforcoolingzone.優化冷卻區回流曲線2.ConveyorshakinginPCAcoolingdownphase:Repairthe

conveyorperactualstatus.冷卻階段傳送帶震動:根據實際情況調校傳送帶．2025/6/2428SolderProjections/錫尖Solderprojectionviolatesassemblymaximumheightrequirementsorleadprotrusionrequirements.焊錫毛刺違反組裝的最大高度要求或引腳凸出要求.Solderprojectionviolatesminimumelectricalclearance.焊錫毛刺違反最小電氣間隙.2025/6/2429SolderProjections/錫尖Countermeasure1.Lessfluxonboard:Increasethefluxsprayrateonboardbeforegothroughwavesoldering(wavesolder).助焊劑不足:增加助焊劑的噴射量

2.Lowconveyorramp:Raisetheconveyorrampperactualstatus(wavesolder).傳送帶角度過小:根據實際情況校正傳送帶角度3.Excesspreheattemperatureandtime(fluxdryoff):Optimizewavesolderingprofile.(Wavesolder)預熱過度（助焊劑過度揮發）:優化波峰曲線(波峰焊)4.Causedbyrework:Standardizeoperatorhandlingandenhancevisualinspection.返修中產生:規范員工操作加強目檢.2025/6/2430NoSolder/無錫

Nosolder

to

the

land

or

termination

where

solderisrequired.焊點無錫2025/6/2431NoSolder/無錫

Countermeasure/對策1.Missingprinting/漏印Rootcause:a)Stencilaperturewasjammed./鋼網堵孔b)Highviscosityofsolderpaste./錫膏粘性過高Action:a)Cleanstencil;/清洗鋼網b)Replacetherecycledpastewithfreshone./更換新錫膏c)Printingmachineparameteradjustment./校正絲印機參數2.Poorsolderabilityofcomponentorpad./元件或焊盤可焊性太低Rootcause:a)OlddatecomponentorPCB./陳舊元件或PCB板b)ContaminationoncomponentorPCB./元件或焊盤受污染Action:Purgethematerialforfurtherdisposition.

/清除來料3.Insufficientfluxvolume:increasefluxsprayrate(wavesolder).

助焊劑量不足:增加助焊劑噴射量(波峰焊接)4.Preheatexcess:lowerpreheattemperatureproperly(wavesolder).預熱過度:適當降低預熱溫度(波峰焊)5.Chipwaveorsolderwaveheightislow:properheight(wavesolder).波峰高度過低:調整到適當高度(波峰焊)2025/6/2432InsufficientSolder/少錫Insufficientsolder焊錫不足2025/6/2433InsufficientSolder/少錫

Countermeasure/對策1.Stencilaperturecloggingcauseincompletesolderprinting):Automaticormanualcleanthestencil.鋼網孔堵塞導致錫膏不完全印刷:自動或者手工清洗鋼網2.Noenoughsolderpastevolume(PasteheightunderLCL):VisualinspectionandCpkcontrol.錫膏量不足(錫膏高度在LCL以下):目檢和Cpk控制3.Solderpasteprintmisalignment:Finetuneprintingmachine錫膏印刷偏位:校正絲印機使之最優

4.PoorsolderabilityofcomponentorPCBpad:元件或PCB焊盤可焊性差a)Optimizereflowprofile.優化回流曲線b)Exchangethepoorsolderabilitycomponent.更換掉低可焊性元件5.Excessglueorgluemisalignment:Finetunescreenprint(wavesolder).點膠過多或點膠偏位:優化絲印參數6.Lessflux:Increasethefluxsprayonboardbeforeitpasswavesoldering(wavesolder).助焊劑不足:增加助焊劑的噴射量

2025/6/2434?Solderfilletextendsontothetopofthecomponentbody.焊錫接觸元件體．ExcessSolder/多錫2025/6/2435ExcessSolder/多錫

Countermeasure/對策1.Excesssolderpaste:錫膏量過多a).SolderpasteheightoutofUCL:Adjustprintingmachinetocontrolthepasteheight.錫膏高度超出UCL:校正絲印機控制錫膏高度b).Nonstandardofstencilapertureopening:standardizethestencilapertureopeningfordifferenttypecomponents.鋼網開孔不標準:為不同類型的元件設置相應鋼網的開孔標準2.Wavesoldering/波峰焊接a)Lowconveyerramp,longwavesolderingtime:Adjustconveyorrampangleto5~7degreeandsolderingtimeto3~5second.

傳送帶角度過小,波峰焊接時間變長:校正傳送帶角度到5~7度,焊接時間3~5秒b)Highpreheattemperaturetodryofftheflux:Accordingtofluxspectocontrolthepreheattemperature,normallythePCBsurfacepreheattemperatureshouldbeunder100oC.高預熱溫度造成助焊劑過度揮發:按照助焊劑的規格控制預熱溫度,通常,PCB表面溫度一般低于100oC2025/6/2436WrongOrientation/Polarity反向,極性反

Correctpolarity/正確的極性Wrongpolarity/極性反Thismarki