SMT的內容情況說明

FLE>XTRONICSSMTdefect&countermeasure-level

I

SMT

缺陷及防范措施FLEXTRONICS·

Objective/

目的·SMTDefectsIdentification/SMT缺陷

確

定·Failureanalysismethodandprocedure/

缺陷分析的方法及流程

·SMTDefectsandCountermeasure/SMT缺陷及防范措施>Tombstoning/

立碑>Solder

Bridge/橋聯>ComponentDamaged

(Nicks,Cracks,orStressFractures)/元件損壞

>Misalignment/

偏位>ComponentLeadLifted

元件引腳翹高>SolderBall/

錫珠>Non-Wetting,Dewetting/虛焊，半潤濕>Cold

Solder/冷焊>Disturbed

Solder/焊錫紊亂>NoSolder/無錫>InsufficientSolder/

少錫>ExcessSolder/

多錫>WrongOrientation/Polarity/

反向，極性反>SolderHole/錫洞>Solder

Projections/錫尖>Others/其它FLEXTRONICSSlide

Contents2>

Know

the

common

defect了解常見缺陷類型

Analyzethepossiblecause分析可能的原因Countermeasureforthedefects基于以上原因采取的對策Objectives/目的FLEXTRONICS

3ldentify

the

SMT

defects

according

to

IPC-A-610

(Rev:D)根據

IPC-A-610(Rev:D)

確定缺陷.This

standard

is

a

collection

ofvisual

quality

acceptability

requirements

forelectronic

assemblies.IPC-A-610

是關于電子組裝外觀質量驗收條件要求的文件.ASSOCIATONCONNECTING。ELECTRONICS

INDUSTRIESFLEXTRONICS

4SMT

Defects

Identification/SMT缺陷確定Source:MPM'sA

user'sguidetomorepreciseSMT

printingFLEXTRONICS

5Major

Contributor

to

Defects/

缺陷的主要分布Incoming

Component

Failure

Analysis

缺陷分析FLEXTRONICS

6FailureAnalysis/缺陷分析WheretostartyourInvestigation-"Threesimple·Allthe

Products,allthe

time?所有的產品.任何時候?>Process

problem流程問題·Someofthe

products,someofthetime?部分產品，某些時候?>Process

or

Material

problem流程或物料問題·Someofthe

Products,allthetime?部分產品，任何時候?>Material

problem物料問題FLEXTRONICSi.e.,equipment,operator,etc.如：設備.作業(yè)員等questions”三個簡單問題7Two

Avenues

of

Investigation/

兩種調查途徑·

Historical

Research歷史記錄調查·

Tests

&Evaluations測試，評估FLEXTRONICS

8·Supplier

data供應商數據>Change

變

更Design

設計|

Material物料Process

流

程>Quality

tests?

品

質

測

試

?·Production

Records

生產記錄>Materialhandlingrecords物料記錄>New

batch

新批次>QAorInspection

reports/QA

或檢查記錄>Traceabilityreports&Validations

可追溯性報告

>SPC

data/SPC數據·

Environmental

Records環(huán)境記錄>Temp&Humidity

溫濕度>Power

電力>Maintenance

保養(yǎng)FLEXTRONICS"Historical

Research"

歷史記錄調查9Tests

&Investigations/

測試，調查·Inspection

檢

查>Visual

外觀>Chemical

化學>

Mechanical

機

械·

pe

ocess

if

possible

重復流程>Break

down

process

steps

細分流程

ed

op

l

隔離離物人料員>Functional

(parametric)功能(參變量)

>Materialsanalysis物料分析s隔nsratioateriaemIsolatIsolatedat

pr測

試etsResFLEXTRONICS

10·

Definethe

problem

precisely精確定義問題所在·ldentifytheprecisetimeoffirstoccurrence確定首次問題發(fā)生時間·Identifythosefactorswhicharecapableofcausingthe

problem確定可能導致問題的因素·

Don'twastetimeon

parameterswhichcannot

reasonably

impactthedefect不要在那些不是主導因素上浪費時間·

Investigatethosefactorssystematically系統的研究這些因素FLEXTRONICSFind

The

Root

Cause/

找到問題的根本原因11Factorsresult

inthedefects.Themany

interactionsshowthatthey

must

be

related

as

asystemandbere-evaluatedwhenchanges

occurs.FLEXTRONICS"Fish-bone"Chart/

魚骨圖Equipment設備

Methods方法Humidity濕度Temperature溫度Environment環(huán)境

Man

人Training培訓Authority認證Attitude態(tài)度Materials物料12Effective

Use

of

Background

Information/

有效利用信息·

Design

Data設計數據·

ConceptualAnalysis概念分析·

DOE's實驗設計FLEXTRONICS

13Control

to

guarantee

performanceFLEXTRONICS王

王nDF

ove

byfixingwhat'swrongDefinewhatsimportantasure

howwe'redoinglrre

what's

wrong3.donTty

FootCaucoPrapo

ced

CslulonemThe

DMAIC

Process/DMAIC

流程#a01GouE14SMT

Defects

and

CountermeasureSMT

缺

陷

及

防

范

措

施SMTDefects

and

Countermeasure/SMT缺陷及防范措施FLEXTRONICS

15

i

ents

standing

on

a

terminal

end片式元件末端翹起(墓碑)gonpnmbstop

comhitoCFLEXTRONICS

16Tombstoning/立碑Countermeasure/對策Mechanism:Surfacetension

incomponentterminal

isuneven

in

reflow.原理：在回流過程中零件兩末端的表面張力不均衡.1.Componentterminal

heatdistributedunevenly零件兩末端受熱分布不均衡.Insufficientsoaktime:Reflowprofileoptimization.保溫區(qū)時間太短：優(yōu)化回流曲線參數.2.PCB

Paddesign

issue(the

padsdistance

istoo

big):

DFM(DesignforManufacturability)to

improve

PCBpaddesign.PCB焊盤設計問題(焊盤間距太大):DFM以改善PCB焊

盤設計.Tombstoning/立

碑FLEXTRONICS17Tombstoning/

立

碑Countermeasure/對策3.Component

terminal

oxidization

or

contamination:Solderability

test

if

necessary

andRTVthedefect

material.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:Optimizethe

P&Pmachineparameters.貼片偏位：優(yōu)化貼片機的參數.6.Stencilaperturedesign

issue:studyand

improvetheaperturedesign.鋼網開孔的設計問題：研究并且改善開孔設計.FLEXTRONICS

18Solder

Bridge/

橋聯·A

solder

connection

across

conductors

that

was

joined.·

Solderhas

bridgedtoadjacent

non-commonconductoror

component.焊錫橋連到相鄰的非導體或元件.FLEXTRONICS

19焊錫在導體間非正常連接.Countermeasure/

對策1.Screenprintingissue/

絲印問題：a)Paste

height

out

of

UCL:Adjust

the

printer

to

control

the

paste

height.錫膏高度超出控制上線：校正絲印機，控制錫膏高度.b)Paste

printing

misalignmentor

bridging:Fine

tune

printing

machine./錫膏印刷偏位或者橋聯：優(yōu)化絲印機.c)Icicle

printing:Fine

tune

printing

machine

or

change

to

lowerviscosity

paste.絲印拉尖：優(yōu)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.Solder

Bridge/

橋聯Pastecollapse錫膏塌陷FLEXTRONICSIcicle

printing

絲印拉尖Misalignment印刷偏位Bridging橋聯20Countermeasure/對策2.Pick

&Placement/貼片a)Componentplacingmisalignment:Finetunethe

P&Pmachine

.元件貼片偏位：優(yōu)化貼片機的參數.b)Highpressureforplacement:reducepressureto

propervalue

.貼片壓力過大：減少壓力到適當的參數.3.Wavesoldering/波峰焊a)Lowconveyorramp:Raisetheconveyorramp

peractualstatus.傳送帶角度過?。焊鶕嶋H情況加大傳送帶角度w

d

n

board:Increase

the

flux

spray

volume

on

board

before

going

through板上的助焊劑較少：波峰焊接之前加大助焊劑的噴射量goinxerflulsosseeLSolder

Bridge/

橋聯FLEXTRONICS21Component

Damaged(Nicks,Cracks,orStressFractures)/元件損壞Nicks,cracks,or缺

口

，

裂

紋

，

壓stress痕fractures.FLEXTRONICS22Countermeasurel對策1.Rawmaterialdamagedpurgethebatchmaterial/來料損壞：清除這批來料

rd

n

agn

n.(Fixture

or

machine

touch

it):Investigate

and

take

corectiveoperatioprocessdTdarSMsrinuoeonsamaa2在SMT

流程中損壞(夫具和設備接觸):調查分析并且對不規(guī)范的操作作出矯正行動3.Fast

cooling

rate

on

rerlow

process:Control

the

SMA

cooling

rate

to

below

4degree

per

second.在回流過程中冷卻速率過快：控制SMA

的冷卻速度使斜率保持在每秒4度以下Typicalreflowprofile/回流曲線典例：Component

Damaged(Nicks,Cracks,orStress

Fractures)/

元件損壞Reflowtime(s)FLEXTRONICS23FLEXTRONICS

24Misalignment/

偏

位Countermeasure/對策1.P&P

machine

function

unstable:Fine

tune

the

P&P

machine.貼片機性能不穩(wěn)定：優(yōu)化貼片機性能參數.a)FinetuneX,Ydata/

調整X,Y坐標b)Optimize

pick

and

placement

parameters./

校正吸料和貼片的參數.2.Component

termination

oxidization:Solderability

testif

necessary.Purge

the

failedmaterial/

元件末端氧化：可焊性實驗，清除不合格的來料.3.Operator

touch

the

component

prior

to

reflow:Standardize

the

operator

handling(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)Misalignment/

偏

位FLEXTRONICS25Component

Lead

Lifted

元件引腳翹高One

lead

orseries

of

leads

on

component

is

out

ofalignment

andfailstomakecontactwiththe

land.元件一個或多個引腳變形不能與焊盤正常接觸.dj

sintnotoirednoLeaursoJ-ase

pofhtmhnoogttiointformatTohuecbhWhenexaminingthe

toes

of

the

leaditcanbeobservedthatthese

have

liftedfromthecircuit

board.FLEXTRONICS26Component

Lead

Lifted/

元件引腳翹高Countermeasure/對策1.Component

lead

bent

before

placement:Sort

the

defective

part

and

return

it

to貼片前元件引腳變形：挑選出缺陷元件，退回供應商.2.Manual

placement

the

loose

part:Inspect

the

part

before

pass

it

to

reflow.手放散料：回流前目檢.FLEXTRONICS27vendor.Solder

Ball/

錫

珠·Solder

balls

are

spheres

ofsolderthat

remain

aftertheelectricalclearance.焊錫球是焊接后形成的呈球狀焊錫.·Solderfines

are

typically

small

balls

ofthe

original

solder焊錫殘渣是在回流中形成的小的球狀或不規(guī)則狀焊錫球.ld

z

l

lattered

around

thespssceeroavphwatohftreehesitngeneirurscnaioetctmnetensoacpsoldering

process.Solder

balls

violate

minimumFLEXTRONICS28Solder

beadingSolderbeadsbeneaththe

component

M.BleiseFLEXTRONICS

29Mid-Chip

Solder

ballingSolderballsunderthe

componentSolder

Ball/

錫

珠MoreVolume

of

solder

paste

printedSolder

paste

Solder

beadOccurrenceof

solderbead

(%)EKRALowLesspe**en

Te+nee2yHighCountermeasure/對策1.S

tencilAperturedo

notfocustopad: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(tài).3.Excess

paste:Cpk

control.多錫：Cpk

控制.4.Damp

PCB:Bake

the

PCB

before

loading

it

to

SMT.PCB焊盤受潮：

SMT

組裝流程之前烘烤PCB.6.Stencil

polluted:cleanthestencil.

鋼網臟污：清洗鋼網.7.Profile

ramp

up

is

too

fast:Optimize

reflow

profile.回流曲線升溫速度過快：優(yōu)化回流曲線.8.Pasteoxidized:exchangewithfreshsolderpaste.錫膏氧化：更換新錫膏.9.Chip

wave

or

solder

wave

height

is

too

high

caused

excess

solder

to

top

side:adjustthe

wave

soldering

height

to

proper

level

(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).FLEXTRONICSSolder

Ball/

錫珠30·is

s

not

wetted

to

the

land

or

termination

where

solder虛焊：需要焊接的引腳焊盤不潤濕.·Solder

coverage

does

no

meet

requirements

for

the·Dewetting

as

a

condition

resultswhen

molten

solder

coats

asurface

and

then

recedes

to

leave

irregularly-shaped

mounds

d

of

solder

and

with

the

basis

metal

or

surface

finish

not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(qū)域，焊錫形狀不規(guī)則.silofpnexthiedharrrequiSoldeNon-Wetting,Dewetting/虛焊，半潤濕ofsolderthat

areseparated

by

areasthat

are

covered

with

atermination

type.FLEXTRONICS31Non-Wetting,Dewetting/

虛焊，半潤濕1.Poor

solderability

of

component

or

pad./元件或焊盤可焊性太低Root

cause:a)Old

date

component

or

PCB./陳舊的元件或PCB

板b)Contamination

or

oxidation

on

component

or

PCB.

元件或焊盤污染或氧化Action:Purgethematerialforfurtherdisposition./清除來料2.The

paste

out

of

its

life

time:/錫膏超出有效期Scrapthe

lot

pasteand

replace

itwithfreshone報廢有問題的錫膏，更換新錫膏FLEXTRONICS

32Cold

Solder/

冷

焊·

Incomplete

reflowofsolderpaste.

焊錫回流不完全FLEXTRONICS

33Countermeasure/對策1.Peaktemperature

istoo

loworreflowtime(dwell回流峰值溫度太低或者回流時間不夠：重設溫度曲線圖

.Typical

reflowprofile:/

典型的回流曲線ColdSolder/冷焊time)is

not

enough:Re-setup

the

profile

to

fulfill

thepaste

spec

or

customer

provided

spec.requirement.ttt

廣CFLEXTRONICSmxmme(()34Time時間tc3

-large

SMD35tc1-small

SMDFLEXTRONICSToo

Hot!Too

Cold!Cold

Solder/

冷

焊Temp.

溫度250℃230℃tc1-medium

SMDCold

Solder/

冷

焊Countermeasure/對策2.The

component

in

some

location

covered

with

reflow

pallet

(Peak

temperature

istoo

low

or

reflow

time(dwell

time)is

not

enough):Enlarge

the

pallet

open

window

forthedefect

locationstoreducethe

△T.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(△T).FLEXTRONICS

36Disturbed

Solder/

焊錫素亂·Disturbedsolder

jointcharacterizedbystress

linesfrommovementin

the

connection.在冷卻時受外力影響，呈現紊亂痕跡的焊錫Countermeasure

/對策Check

and

adjust

the

cooling

airspeed

and

conveyor

status.檢測調整冷卻風速和傳送帶狀態(tài).

FLEXTRONICS37No

Solder/無錫No

soldertothe

land

orterminationwhere

solder

is

required.

焊點無錫FLEXTRONICS38Countermeasure/

對策1.Missingprinting/

漏印Root

cause:a)Stencil

aperture

was

jammed./鋼網堵孔b)Highviscosityofsolderpaste./

錫膏粘性過高Action:a)Cleanstencil;/清洗鋼網b)Replacethe

recycledpaste

with

fresh

one./更換新錫膏

c)Printing

machine

parameter

adjustment./校正絲印機參數2.Poor

solderability

of

component

or

pad./元件或焊盤可焊性太低

Root

cause:a)Old

date

component

or

PCB./陳舊元件或PCB板b)Contamination

on

component

or

PCB./元件或焊盤受污染

Action:Purge

the

material

for

further

disposition./清除來料3.Insufficient

flux

volume:increase

flux

spray

rate

(wave

solder).

助焊劑量不足：增加助焊劑噴射量(波峰焊接)4.Preheat

excess:lowerpreheat

temperature

properly(wave

solder).

預熱過度：適當降低預熱溫度(波峰焊)5.Chip

wave

or

solder

wave

height

is

low:proper

height

(wave

solder).

波峰高度過低：調整到適當高度(波峰焊)FLEXTRONICSNo

Solder/無

錫39Insufficient

Solder/

少錫Insufficientsolder焊錫不足FLEXTRONICS40Countermeasure

/對策1.Stencil

aperture

clogging

cause

incomplete

solder

printing):Automatic

or

manual

clean

the

stencil.鋼網孔堵塞導致錫膏不完全印刷：自動或者手工清洗鋼網

i

a

ti

l

dp

c

l

e(Paste

height

under

LCL):錫膏量不足(錫膏高度在LCL以下):目檢和Cpk

控制3.Solder

paste

print

misalignment:Fine

tune

printingmachine錫膏印刷偏位：校正絲印機使之最優(yōu)4.Poor

solderability

of

component

or

PCB

pad:

元件或PCB焊盤可焊性差

a)Optimize

reflow

profile.優(yōu)化回流曲線b)Exchange

the

poor

solderability

component.

更換掉低可焊性元件5.Excess

glue

or

glue

misalignment:Fine

tune

screen

print

(wave

solder).

點膠

過多或點膠偏位：優(yōu)化絲印參數6.Less

flux:Increase

the

flux

spray

on

board

before

it

pass

wave

soldering(wave

solder).助焊劑不足：增加助焊劑的噴射量olmtrunoovktepsCanooschegpusoinnleuosNV2.Insufficient

Solder/

少

錫FLEXTRONICS

41·Solderfillet

extends

ontothe

top

of

the

component

body.

焊錫接觸元件體.FLEXTRONICS42Excess

Solder/多錫Countermeasure/對策1.Excess

solder

paste:錫膏量過多a).Solder

paste

height

out

of

UCL:Adjust

printing

machine

to

control

the

paste

height.錫膏高度超出UCL:校正絲印機控制錫膏高度b).Nonstandard

of

stencil

aperture

opening:standardize

the

stencil

aperture

opening

fordifferenttypecomponents.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.Wave

soldering/波峰焊接deag)a

nsvoel

i

3w~a5v

l

ring

time:Adjust

conveyor

ramp

angle

to

5~7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)High

preheat

temperature

to

dry

off

the

flux:According

to

flux

spec

to

control

the高預熱溫度造成助焊劑過度揮發(fā)：按照助焊劑的規(guī)格控制預熱溫度，通常，PCB表面溫度

一般低于100℃FLEXTRONICSoocsseetnelomp,timganrrreencreeLowExcessSolder/多錫preheat

temperature,normally

the

PCB

surface

preheat

temperature

should

be

under100℃.43Wrong

Orientation/Polarity

反向，極性反Wrong

Polarity/極性反44CorrectPolarity/

正確的極性FLEXTRONICSWrong

Polarity:/極性反Anode

mark

onCorrect

Polarity/正確的極性Wrong

Polarity/

極性反Anode

mark

on

on

PCB.D503Cathode

mark

on

PCB.tantalum

capacitorCathode

mark

oncomponentbody.body.Wrong

Orientation/Polarity

反向，極性反WrongOrientation/反向：The

IC

is

populated

in

inversedirectiononthe

PCB.IC被反方向組裝在線路板上FLEXTRONICS

45WrongOrientation/反向Correctdirection/正確的方向IC

direction

markon

PCB.IC

direction

markon

the

device

body.PBU014Countermeasure/對策1.Wrongplacementmachineprogram:Checkand

correctthe

machine

program.貼片機程序錯誤：檢查和更正機器程序2.Manual

placement

in

reverse

direction:

手工放置元件錯誤a)Avoidmanualplacementcomponents

避免手工放置元件b)Need

special

inspection

for

the

manual

placement

prior

to

reflow(document

control).爐前需要特別檢查那些手工放置的元件(文件控制)3.Disorderedorientation

inthetray/reelofthe

incomingmaterial:卷裝或盤裝來料元件的不規(guī)則放置.a)Inspectbefore

loading

ittoSMT.上料前檢查來料b)Feedbacktovendortotakecorrectiveactions.反饋給供應商采取改善行動Wrong

Orlentation/Polarity

反向，極性反FLEXTRONICS46SolderHole/

錫洞·Blow

holes,pinholes,voids吹孔，針孔，空洞FLEXTRONICS47Countermeasure/

對策1.Insufficient

preheat:Reflow

profile

optimize.預熱時間不足：優(yōu)化回流曲線設置.2.Ramp

up

is

too

fast:Re-setup

the

reflow

profile

to

make

it

optimize.

升溫速率太快：重設回流曲線圖使之最優(yōu)化.3.Excessfluxinsolderpaste:properlytoincrease

preheat

time

and

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

PCB:Bakethe

PCBbefore

loading

ittoSMT.PCB受潮：SMT

組裝前烘烤PCB板.5.Co

mponentfeetoxidation:Bake

itbeforeSMTorrequirevacuum

packing

on

incomingmaterial.元件腳氧