SMT工程師應(yīng)具備的設(shè)計(jì)技能

SMT工程師應(yīng)具備的設(shè)計(jì)技能

--如何應(yīng)用DFM

DFM：Designofmanufacturing

創(chuàng)于70年代初，在機(jī)械行業(yè)用于簡化產(chǎn)品結(jié)構(gòu)和減少加工成本。

1994年SMTA首次提出DFX概念。1995年DFX是表面貼裝國際會(huì)議的主題。

DFX：DFM；DFT/D；DFA；DFE：DFF：DFS；DFR

?DFA:DesignforAssonibly,systemlevelmechanicalKMnnbty力，6?，

?DFE：DesignforEnvironment,為H嚏保少0A佇設(shè)計(jì)

?DFF:DesignforFabricationofthePCBVf］為印剜電得收就T嘛S!位梭+

?DFS:DesignforSourcing,i.e.SupplyChain為，潼?媽的&計(jì)

?DFR：DesignforReliabiltty.UM,產(chǎn)4可?性及運(yùn)?安全號(hào)方叫

.OFx:DesignforMX*,includesallofthe?boveDFM：山處"

1.設(shè)計(jì)對(duì)SMT的質(zhì)量的影響

。60%的產(chǎn)品成本來源于早期的設(shè)計(jì)

?75%的制造成本來源于設(shè)計(jì)

o70-80%的生產(chǎn)缺陷直接與設(shè)計(jì)有關(guān)

設(shè)計(jì)不良

。造成大量焊接缺陷

。增加修理及返修工作量，浪費(fèi)工時(shí)，延誤工期

o增加工藝流程，浪費(fèi)材料

。返修可能會(huì)損壞元器件和印制板

?返修后影響產(chǎn)品的可靠性

。造成可制造性差，增加工藝難度，影響設(shè)備利用率，降低生產(chǎn)效率

。嚴(yán)重時(shí)重新設(shè)計(jì)，導(dǎo)致產(chǎn)品開發(fā)周期長

下面是幾種設(shè)計(jì)不良例子

I.IC流向不合適

2.焊盤設(shè)計(jì)不合適

采用DFX的好處

1.有利于制程的標(biāo)準(zhǔn)化

2.有利于技術(shù)轉(zhuǎn)移，簡化產(chǎn)品轉(zhuǎn)移流程

3.降低新技術(shù)引進(jìn)成本，減少測(cè)試工藝開發(fā)的龐大費(fèi)用

4.節(jié)約成本，改善供貨能力

5.迎合PCB/SMT技術(shù)日趨復(fù)雜的挑戰(zhàn)

2.工藝制造流程與設(shè)計(jì)

采用表格形式

2.1定義工藝流程

f

2.3定義工藝流程

CheckupItemmentsDFx

Proc*.Flow

P7HAssembly（13）CcjnsidefpressMpaste-inIetc19ProcessFkw/"erarcW決定

sdttef.changetoSMT巴丹

EhmtnaietheseprocessesI9Prodbi*IluwIherarchy

6NorvstanOardAnynonstandardpfoct^seS1*J?I-A...,!..i，匕1：/

_0cgs（14）required?

7WreAods/DeWesElwnmatethem.T44HandWnusoiWHC

23

N（?！保珼FMTE3科。（UGY

PTHAwembly

,,?,，」，I….L1”:一.A

jComponenlB

?Hot*?ize

pco.cteftdocticn.cg

.Componentchwancet

peoeMJrot.山壯formw*

1PC8torncnElwaMecomponents?1，田mfiHreh?H

j.etc

DFxGuideSection:1.9Proc皿NowHierarchy

V^iorewer49c:Non<i-----------------------------

―“srowawr

F

D^lh-------■——PTHAssembly

a叉f

ConsidercompatibilitywiththePCB,component,andgeneral

boarddesign:

Componenttypesavailable(solderedPTH,pressfitzSMT)

Othercomponenttypesontheboard

Componentleadlengths

Componentleadsizeandshape

Componentleadpitch

Componentleadsurfacefinish

Componenttemperatureresistance

Componentstandoffs

PCBsurfacefinish

PCBthickness

Finishedholesizeofplatedthroughholes

Etc.

ManualSoldering

Hinimtrenwmualsolderingandsolderfountainattachbyselectingcomponents

■nddesigningtxMrdlayoutforhigheryielding,moreautomatedbatch

processes*e.9.autoSMLP^steinhole,fullorselectivewavesolder,pressfH

Examples:

?Fton-reflowableSMIcomponents

?Double-sidedsolderedPTHcomponents

?Secondarysidecomponenttooheavy

?Secondarysidecomponenttootall,8aselectnrewavesoAderbcwil

?FewSMTcomponentsplacedonsecondaryside(toofewforaiMornated

(me)

?Etc.

DFnGuideSection;1.9ProcessFlowHierarchy

coverage：Kone

2.2PCB外形

2.4PCB外形

1

ChecklistHemCommentsDFxGutdeltnesReferencesfntemaf'

BoardOutline

BoardSize(2)Checkequipmentcapabtlrty44PdneUBoardIbicKnessandSue

matnx.

8MasterPandUtilizationOptrmizecardsi/cUseVakx<>(52MasterPandOpumzqon

0)"panelexeM

10BoardOuthneShapeComptexil-0depafmilZdlion58CadDepaixH心tvon

routing

11ComerChamfom(10)AH4conun5PicwntsIKnd59CotnerChamfers

damageDesignednoltointeffuic

wKhptecemont■ensorr

2.3拼板

Reasonsforl,aneling:

-Stitdllcircuit

.Hetterspace〃〃/

(luhrirulion<"八〃

-(InlineAspectRatio

-PnHhicfiiHivolumebalancing

(doublercjlowj

H

DFMexampleMd$(erp.mei

iJ99

33%Boarduvings

bychangingtho

carddimensions

Previously

panelizedas2-up.

(WMTEaaXQGY

2.4元件

ItemmvntsDFxGuidehn,sReferences

］，>UJM?C65ormMWtiQatHjnNA

IneededPadgeometiyconsistent

rr?thcM?Kt-alpan?

MlportswMheMe?VWtoMhte^213ProceiBCornpfdiMrtyRequwement%

QIPtcxBGAi^JtDEClrayi.219Compof?efTlSuppty/Packagmg

rnwtualputstubesow<Formats

h-p」S?gw(?gbeyi).崎

f>||tW［；&wH________

tanBOMRar?c/tfianynon*pRM>uctonpaft^

pi。to”■BUMrv4，5??gt?i

twaiJ，，___________

Cof*iOwcoriwrt'fig?*』，OIo721

B<Vs—

星）F2.5元件

r-----------------------------

f

Comments______DI,ii.td.'hnGbReferuncosOntcrnal)

/Component

Plicemsnt

29lpTHon1sideonlyMoveto1sideOfHy.19ProcessFlowHierarchy

814SMTWeightLKTHISforSide2

!XiComponontWeightPartsfacingoff闔SMTmoveto

topside

3HCcmponentlieigfrt(24)Checkbottomsideheiglitfurwase812HeightLimitations

&ICT.topsidekxflyingprobe,

AOI.&Xray

I32iSMTcomponentsinMlComponentsonbacksidesuture813WaveSolderedSMTComponents

eesdder(25)forfullwave?

33llopside/BottomsidePlacementtimesbalancedRxDS811SMTUneBalance

__prance___line?

2008/06/1011:18

…w-

CorriponentHeightLimitations

<

EquipmentTopBottom

MT51mm(2")254mm(1")

WaveZbrnin(31)3.8mm(0.150")i

95nun(0375iMax

[Xray30mm(12")254n【n(V),

/AOI(MVP)25.4mm(D1521nm(6")

AO?(RTI)51mm(2")51mm(2”)

ICT762nun(03")Pf3

635IIHII(25)MJA

f「lyingProbe20nini(079)20nnn(UZ9)

Rework(AilVac)44mni(1.75")254mrn(1")

Rework(SRT)70mm(275")3UIHI11(15)

,For)Cray,thesidewithsurfacemappointsisconsideredbuttum>2*

TopSide/BottomSideBdlonce

Example:

?Double-sidedlineconfiguration:

?1MVIIFonbackside

?3MVIIF+1MPAontopside

TopBottomOpUcnuinTopUuttont

BGA/tfP100|BGA/QFPU)

PLCC/TSOP301PLCC八SOP30

1______39

^SOfC/Taot17839SCMC/Taut?

1

DiscrutuI13201O.，

Dscratt1422410?

一-

〔

Placementgate:62secondsPlacenianlgje57seconds

(mov6102disCestubutK>m)

=9%higherthanoptimum

orAIrroMxdit>/1011:23

2.5元件貼裝

2008/06/1012:13

FPanelEdgeKeepouij-SifigleniRMieAast-.nblypans

2inm(0.080")

onleading/

tidihngends

Indudesrequirementsforallassembly&testequipment.AppliestoSMI&

pasteinhofecomponents,onbothsidesofthePCB.

COMWMN7ORIENTATION

BREAKAWAYEDGE

Hr”ka“?y

nffjc、

J5mm

picfrifril

oiicnlAfhm

ComponentSpacing

―—

"SMIbMi"&SOP

Id

0.050-

o.o3(r

2008/06/1012:16

1■■■■■■■i

2.6

,

二lljCc—muwttOF*G.*■?■fWe—e?)

UMorPGM?camrxjP1>t8S4S4iicswW?m<SOMW

^GmvcrwrWwpaMficompwi

CMPBCBGAAFrwpartsnorba?BC8G<

blowrw^

CM01ySenderCan?*>yiodvfort*qp^cec*aeix

JamjoegQH39aM

AUtoPIMErcx^hpatstoJUtcmAV?8.2Comf?rw<Mf,■>>ctAutomned?

MacNnesKie>tthat47PIHtxa>4n

FTHdesignrU?i

aAmarese^odfarMhibeta512PCbPjifNixntMnng

26Hoieanuviu

1ChecklistItem

CommontsDFKGuitklirtesRuf^rcm.e%(Internal)；

]Hole?&Vias

43TooimgHofcs(9)2forIC1andforFUJISMT54SinglelinageKequtemenU

equipment56hitagcPunvQahuKequtrementsl

44ViamPad(17)Present?Whatsize*4a?75Acceptdblea；dVm

LocohuiB

45ThermalRdiots(19)Arethosepccser*lofsoMeredP1H6133Ibeii向REB

parts?

45Pre?sFitHoleSueCorrecttoierance/nominalsize?NA

47PTHHole/LandSizeCorreclfcxwaveorpastetn「1MSddmeoComponents

hole?864StshKUwWawSokWij

火aeFixtureAnchoringHol。forselecttwwave6tunng

L_"tatei________________present?

ToolingHoles

FMB1

?2holesperImageforICT

?3-1Bmm(0.125*)diameter

preferred

?LocMedasfarjp^rtaspoatbte.

4Mh8Cfl^QOTMl

?Hon-symmetitoprevent

incorrectb(?rdpiacementon

fixture

?2holesperAssemblyPanelforSMT

?4.0mm(0.157")diameterpreferred,3.18mni(0.125*)??<<<plc%l

?Centreslocateddt5mm(0.197*)fromedgeufAP

G'""Section:5.6M”ltiInnigrP4inellzationRe(|nif<n>.nt.

ToolingHoles

Minimum5hnrn(02000)

coni[>ononlkoopoutfromhoM

edge,bothofPCB

Nonplatedhole,skntolerance

of?0076imn/0.000mm

(?0.003”/。000”)

L"<GviJt?Station;54MngloImugcRcquHrmrnt5(NoF\inrhi?iUon)

甲o(hù)ccultkfHHrt("vcicdmchzk?__…，,……

ViaInPad

Dcf>cndhigOHUIUMJUIH，

volumu乂?37ne<tvuklvr

iMini|r^creiiludonthu

backside<>tthesdnu?y

dtlectsciceilingtoradjacunt

tinepilchdevices.

Attemputoavoidinsufficientsolder

rnntsbyincreasingpastescreenedcan

resultinsolderballsorbridging.

0/MJEGMAOCy

2.7PCBExternalLaye.

、In.klr.lIb-mkoiiHiiontbDFxGuithdinesRefurenevs(Interndl)

49Globa*Fidticials(8)2lidvcialsiiM(wrnum,3peMied5?1Smgkjhna?juRequirements

Checkfortracer&stlkscreenin*.),-MultiIni<;ef*andiza!i<xi1<匕中川5生川、

keepout310Globjfiducials

90iRMs(PGPDots)(11)MiHti-uppanel?livenFHAX!HM\56MultiknagePan群"at2nRcqmi9nients

5IIknuytjRqectM.wkb

51LandPatterns0402s.RpacksJoepitchp^d<)(1iijiuryCttjalKX)

vrtdth,lowMtiMKiHIpttits,etc

52Lcx^iFiducialsPieseotonAntspitch?6911ocdhducldhs

53tracesUnderZorofloutingattracesunderpad(og65SM1P.r/*i,A^

StandoffComponentsPp.H.ks,dr,(,I.!(1:.)6/U|Njckt>/Cpjr.k8

54SoKarEMB(23)Forwavesolder.com)cctoi3uridBGdSdcctiiVWuwSohici

fltusd80tCs,

55SurfeiceM叩Powrt^1CMXruyJns(xjcliooHhSiiifiK.oMnpP(MUSkxX-Ruy

GlobalFiducials

Globalfiducialsareusedbythescreeningandplacementmachines(o

opticallyalignAssemblyPanelforpastescreeningandcomponont

placement.

Mm4Ornm(01570dg

soklerrnmikojjenkig.free

ofwIXscreen&traces

MtnIOnim(0040')

duinictcfcopperpatl

NotoLocalFlducIftlH(Compon<rntFiducials)ar。addrottnedInthoComponent

LibraryCnrationsectionottheGuidelino*Document

UM〃C，MXOGV

CANWEHSI

0H05<Illi,0(H)MHIP

?>

1J郎

1651.3、

Slnwi-IH.iHMippnSlKKtUMHMMI

Iondvhiime?1RIO!i

Ic?iiib)lunc|UUppm

LandPatternDesign:

I±1fI

」]II

1^71fT~~]

III]

FPackageTypeG,

4G*iscriticalforgood0402x40.013"

assemblyyield—--—

0603x40.020"

2QWy2lDIMJEOMMUGYfOI

?Landstoofarapartcausedopens(0.030”vs.0.020”)

?Trackrunningunderpartliftscomponentoffthelands

Impact:Defectrateof1990ppm

porcomponent.Onaboardwith

300ofthesecomponents,45%

oftheboardsneededtobe

repairedforRpackdefects.

ufMnoffrotOGr

LandPatternDesign:GullwingParis

n

Mrl

U，L

Z1=L1nom+0.050"

Z2=L2,MJ0.050"

Of*GuQt.9GullwingLeadedComponents

cowyrcurrwtly.y點(diǎn)出a.willba.ddcdinfuture

LandPatternDMiQn；GcAw

■一fi

NoteIt*cnticMftuHOmti

PC8ftHMtthvwWhlvO-

cofnpenwfflIheCAO-，

dimwmlcrhalchannelUIMI1

LocalFiducial

￡

?ni瞅i

Mont

Prwfurred

■Ml

mm

Pcefrrrml

In“/ac。cori^tiahiaddtt?iyn*a

rttr?iyuuffinepit<hpuftscao

&haruloc.dhdiicl.ih.

DFMrrCHMDLOGY

?，；"”)“，"〃■”」U/n/ii"〃1/jgmu/y/.w向，〃“p咪

foMtuF

]p!V

?曲

"Mks，”r

SIA51IIILwaaiosd

F

口S

s

s=O

o=

p=L

.

s=D

o=E

p=R

T

H

H-

HE

&V

—E

二QS

3P

TA

ET

NR

F

SOLDER

THIEVES

心，7,

2.8SolderMaskGuidelines

――.I

CommuntiIDFxR"Bnc”

BcQ—incptfch.CUMRVK”.

FI^MDPMB—Pr?*wNSMDpad*

BGAatenbngorpk^ging*?

/06/1013:16

I-

Spacingviolationbetweenlandandvia.

Notenoughclearanceforasoldermask

web.

Impactriskofsoldermigratingdown

thevia.causinginsufficientsolder

joints.

Potentialsolutions:

?Moveviafurtherfromland

?Reducesoldermaskopeningtopaitiallycover

via(ifnotusedastestpoint)

i?-———______,■■—

2008/06/1013:18

I“頌■岫八

iwrrafNMC.?space.<?AHMI

-MTrriteHe.?rvucmprolikm.SMH

joor??f(J9M"GMJIOGV

2008/06/1013:17

2.9Silkscreen

ICheckNvtlivm(KfllhH.?|L>IH><l<>：；1I...(mb(Hall

|s冊(cè)serve。

159|2sroSlwdoffSHkscioenunderpart(eg@5SMTP-；

|Componentsdiscretes)

^SlkscreenQearanceAroundpads,Ikkidals.Mas.etc412

「

OnentatKnMaricsPofantyOfPin1maikspresent62Ccxu|x4H,irtOti01itau*.viMailes

andfegitte?VisttieonceSwalsoMK!IMWc5np\42nttyposm

populated?，liaptui6ConuLftHoiy(Sieatton

HeferonceDeitgnMmRefDesigiiatompr巴sent70nde，II.*J.i1.KU.H-I()

pad?RefDesignatooilegitsfa

chipfarms?

BGASiBttcreenOuffineOutlinecxit$K)eo^GAp*nnwIer

匈billB3AzeGASilkscrcen

SilkscreenClearance

Example;

SilkscreeninsideBGAland

pattern,tooclosetolands.

Impact:silkscreenmay

encroachontolands,causing

poorsolderjoints.

SilkscreenClearance

Example：

Spacingviolationbetween

fiducialandsilkscreen

knpact：thisfiducialcan'tbe

used

SUk^craen&trace

kevpout.minimum

4.0mm(0.15T*)diametsr

2008/06/1013:20

OrientationMarkings

?

PiQdOtt

Rptfcks

PolaniymarkI-]口

11atcathode口口Rn1

indjcdtor

口CZ3(fortMt&

□CZ]口debug)

TantalumCapacitors

一|Clrclonl?o

□I___Iaccvptablc

—

Pin1

indicator

QFPs

0

OOM

Ptcc?

Ptn1

IndicatorE

Ptn1II

OBDOODOindicator

F

童________2.10PCBAttribute

ChecklistUniCommentsDfxGuidoHrw博Rcfcronee*(Irdsmal

PCBAttributes

64BoardThickness/Thick?wavesdderKsu<rs?4Panel/BoaidThcknenandSize

Strfimss(4)EqupnentcapebthtyIhm/large

nvrnbefu(thtoughliotevasneed

supportatSMT?Repairissues?

Non-standardPCBBonedR&/<xC?Micarta?NA

features(5)

66SurfaceFmsh(6)Compatiblewithcompcxienltypes?49SurfaceFtmih

CompatitMcwithotherSntshes

___present(姆;Gotd

4andDes

67SwckupSymmefiy“nwne：ryofstackup?

_,i~-?——g22CoppeiOstnbutton

CopperSynirneu/_CopperbalancB(xieachlay

jayikn4H-SddcfMask

Sok?TypeT^RecommernJLPIni^tead

30rmoregroundpUnes?impacts

adderboleHIand

2008/06/1013:21

Troughsolderingdirection川也/）向

COMPOSEDIOIUEMATIONVSi<、nowDIKEIIION

WAVE&RtH.OWSt>ihlKi.SG

Oirrctiwtt

ofPCH

flow

""J

ortcntuHun