SMT的内容情况说明

FLE>XTRONICSSMTdefect&countermeasure-level

I

SMT

缺陷及防范措施FLEXTRONICS·

Objective/

目的·SMTDefectsIdentification/SMT缺陷

确

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/桥联>ComponentDamaged

(Nicks,Cracks,orStressFractures)/元件损坏

>Misalignment/

偏位>ComponentLeadLifted

元件引脚翘高>SolderBall/

锡珠>Non-Wetting,Dewetting/虚焊，半润湿>Cold

Solder/冷焊>Disturbed

Solder/焊锡紊乱>NoSolder/无锡>InsufficientSolder/

少锡>ExcessSolder/

多锡>WrongOrientation/Polarity/

反向，极性反>SolderHole/锡洞>Solder

Projections/锡尖>Others/其它FLEXTRONICSSlide

Contents2>

Know

the

common

defect了解常见缺陷类型

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

3ldentify

the

SMT

defects

according

to

IPC-A-610

(Rev:D)根据

IPC-A-610(Rev:D)

确定缺陷.This

standard

is

a

collection

ofvisual

quality

acceptability

requirements

forelectronic

assemblies.IPC-A-610

是关于电子组装外观质量验收条件要求的文件.ASSOCIATONCONNECTING。ELECTRONICS

INDUSTRIESFLEXTRONICS

4SMT

Defects

Identification/SMT缺陷确定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?所有的产品.任何时候?>Process

problem流程问题·Someofthe

products,someofthetime?部分产品，某些时候?>Process

or

Material

problem流程或物料问题·Someofthe

Products,allthetime?部分产品，任何时候?>Material

problem物料问题FLEXTRONICSi.e.,equipment,operator,etc.如：设备.作业员等questions”三个简单问题7Two

Avenues

of

Investigation/

两种调查途径·

Historical

Research历史记录调查·

Tests

&Evaluations测试，评估FLEXTRONICS

8·Supplier

data供应商数据>Change

变

更Design

设计|

Material物料Process

流

程>Quality

tests?

品

质

测

试

?·Production

Records

生产记录>Materialhandlingrecords物料记录>New

batch

新批次>QAorInspection

reports/QA

或检查记录>Traceabilityreports&Validations

可追溯性报告

>SPC

data/SPC数据·

Environmental

Records环境记录>Temp&Humidity

温湿度>Power

电力>Maintenance

保养FLEXTRONICS"Historical

Research"

历史记录调查9Tests

&Investigations/

测试，调查·Inspection

检

查>Visual

外观>Chemical

化学>

Mechanical

机

械·

pe

ocess

if

possible

重复流程>Break

down

process

steps

细分流程

ed

op

l

隔离离物人料员>Functional

(parametric)功能(参变量)

>Materialsanalysis物料分析s隔nsratioateriaemIsolatIsolatedat

pr测

试etsResFLEXTRONICS

10·

Definethe

problem

precisely精确定义问题所在·ldentifytheprecisetimeoffirstoccurrence确定首次问题发生时间·Identifythosefactorswhicharecapableofcausingthe

problem确定可能导致问题的因素·

Don'twastetimeon

parameterswhichcannot

reasonably

impactthedefect不要在那些不是主导因素上浪费时间·

Investigatethosefactorssystematically系统的研究这些因素FLEXTRONICSFind

The

Root

Cause/

找到问题的根本原因11Factorsresult

inthedefects.Themany

interactionsshowthatthey

must

be

related

as

asystemandbere-evaluatedwhenchanges

occurs.FLEXTRONICS"Fish-bone"Chart/

鱼骨图Equipment设备

Methods方法Humidity湿度Temperature温度Environment环境

Man

人Training培训Authority认证Attitude态度Materials物料12Effective

Use

of

Background

Information/

有效利用信息·

Design

Data设计数据·

ConceptualAnalysis概念分析·

DOE's实验设计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片式元件末端翘起(墓碑)gonpnmbstop

comhitoCFLEXTRONICS

16Tombstoning/立碑Countermeasure/对策Mechanism:Surfacetension

incomponentterminal

isuneven

in

reflow.原理：在回流过程中零件两末端的表面张力不均衡.1.Componentterminal

heatdistributedunevenly零件两末端受热分布不均衡.Insufficientsoaktime:Reflowprofileoptimization.保温区时间太短：优化回流曲线参数.2.PCB

Paddesign

issue(the

padsdistance

istoo

big):

DFM(DesignforManufacturability)to

improve

PCBpaddesign.PCB焊盘设计问题(焊盘间距太大):DFM以改善PCB焊

盘设计.Tombstoning/立

碑FLEXTRONICS17Tombstoning/

立

碑Countermeasure/对策3.Component

terminal

oxidization

or

contamination:Solderability

test

if

necessary

andRTVthedefect

material.元件末端氧化或者受污染：根据情况做可焊性实验并且退还缺陷物料.4.Printingmisalignment:adjustprintingmachineparameters.丝印偏位：校正丝印机的参数.5.Placementmisalignment:Optimizethe

P&Pmachineparameters.贴片偏位：优化贴片机的参数.6.Stencilaperturedesign

issue:studyand

improvetheaperturedesign.钢网开孔的设计问题：研究并且改善开孔设计.FLEXTRONICS

18Solder

Bridge/

桥联·A

solder

connection

across

conductors

that

was

joined.·

Solderhas

bridgedtoadjacent

non-commonconductoror

component.焊锡桥连到相邻的非导体或元件.FLEXTRONICS

19焊锡在导体间非正常连接.Countermeasure/

对策1.Screenprintingissue/

丝印问题：a)Paste

height

out

of

UCL:Adjust

the

printer

to

control

the

paste

height.锡膏高度超出控制上线：校正丝印机，控制锡膏高度.b)Paste

printing

misalignmentor

bridging:Fine

tune

printing

machine./锡膏印刷偏位或者桥联：优化丝印机.c)Icicle

printing:Fine

tune

printing

machine

or

change

to

lowerviscosity

paste.丝印拉尖：优化丝印机或者使用低粘性的锡膏.d)Solderpastecollapse:changetohigherviscositypaste./锡膏塌陷：使用高粘性的锡膏.e)Nonstandardstencilapertureopening:Studyandimprovetheaperture./不标准的钢网开孔：研究并改善开孔.Solder

Bridge/

桥联Pastecollapse锡膏塌陷FLEXTRONICSIcicle

printing

丝印拉尖Misalignment印刷偏位Bridging桥联20Countermeasure/对策2.Pick

&Placement/贴片a)Componentplacingmisalignment:Finetunethe

P&Pmachine

.元件贴片偏位：优化贴片机的参数.b)Highpressureforplacement:reducepressureto

propervalue

.贴片压力过大：减少压力到适当的参数.3.Wavesoldering/波峰焊a)Lowconveyorramp:Raisetheconveyorramp

peractualstatus.传送带角度过小：根据实际情况加大传送带角度w

d

n

board:Increase

the

flux

spray

volume

on

board

before

going

through板上的助焊剂较少：波峰焊接之前加大助焊剂的喷射量goinxerflulsosseeLSolder

Bridge/

桥联FLEXTRONICS21Component

Damaged(Nicks,Cracks,orStressFractures)/元件损坏Nicks,cracks,or缺

口

，

裂

纹

，

压stress痕fractures.FLEXTRONICS22Countermeasurel对策1.Rawmaterialdamagedpurgethebatchmaterial/来料损坏：清除这批来料

rd

n

agn

n.(Fixture

or

machine

touch

it):Investigate

and

take

corectiveoperatioprocessdTdarSMsrinuoeonsamaa2在SMT

流程中损坏(夫具和设备接触):调查分析并且对不规范的操作作出矫正行动3.Fast

cooling

rate

on

rerlow

process:Control

the

SMA

cooling

rate

to

below

4degree

per

second.在回流过程中冷却速率过快：控制SMA

的冷却速度使斜率保持在每秒4度以下Typicalreflowprofile/回流曲线典例：Component

Damaged(Nicks,Cracks,orStress

Fractures)/

元件损坏Reflowtime(s)FLEXTRONICS23FLEXTRONICS

24Misalignment/

偏

位Countermeasure/对策1.P&P

machine

function

unstable:Fine

tune

the

P&P

machine.贴片机性能不稳定：优化贴片机性能参数.a)FinetuneX,Ydata/

调整X,Y坐标b)Optimize

pick

and

placement

parameters./

校正吸料和贴片的参数.2.Component

termination

oxidization:Solderability

testif

necessary.Purge

the

failedmaterial/

元件末端氧化：可焊性实验，清除不合格的来料.3.Operator

touch

the

component

prior

to

reflow:Standardize

the

operator

handling(documentcontrol)/

在回流炉前目检操作员碰到贴片元件：标准化操作员操作(文件控制)Misalignment/

偏

位FLEXTRONICS25Component

Lead

Lifted

元件引脚翘高One

lead

orseries

of

leads

on

component

is

out

ofalignment

andfailstomakecontactwiththe

land.元件一个或多个引脚变形不能与焊盘正常接触.dj

sintnotoirednoLeaursoJ-ase

pofhtmhnoogttiointformatTohuecbhWhenexaminingthe

toes

of

the

leaditcanbeobservedthatthese

have

liftedfromthecircuit

board.FLEXTRONICS26Component

Lead

Lifted/

元件引脚翘高Countermeasure/对策1.Component

lead

bent

before

placement:Sort

the

defective

part

and

return

it

to贴片前元件引脚变形：挑选出缺陷元件，退回供应商.2.Manual

placement

the

loose

part:Inspect

the

part

before

pass

it

to

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

Ball/

锡

珠·Solder

balls

are

spheres

ofsolderthat

remain

aftertheelectricalclearance.焊锡球是焊接后形成的呈球状焊锡.·Solderfines

are

typically

small

balls

ofthe

original

solder焊锡残渣是在回流中形成的小的球状或不规则状焊锡球.ld

z

l

lattered

around

thespssceeroavphwatohftreehesitngeneirurscnaioetctmnetensoacpsoldering

process.Solder

balls

violate

minimumFLEXTRONICS28Solder

beadingSolderbeadsbeneaththe

component

M.BleiseFLEXTRONICS

29Mid-Chip

Solder

ballingSolderballsunderthe

componentSolder

Ball/

锡

珠MoreVolume

of

solder

paste

printedSolder

paste

Solder

beadOccurrenceof

solderbead

(%)EKRALowLesspe**en

Te+nee2yHighCountermeasure/对策1.S

tencilAperturedo

notfocustopad:improvestencilapertureopening.

钢网开孔没有对准焊盘中心：改善钢网开孔.2.Printingmisalignment:Finetuneprintmachine.丝印偏位：调整丝印机状态.3.Excess

paste:Cpk

control.多锡：Cpk

控制.4.Damp

PCB:Bake

the

PCB

before

loading

it

to

SMT.PCB焊盘受潮：

SMT

组装流程之前烘烤PCB.6.Stencil

polluted:cleanthestencil.

钢网脏污：清洗钢网.7.Profile

ramp

up

is

too

fast:Optimize

reflow

profile.回流曲线升温速度过快：优化回流曲线.8.Pasteoxidized:exchangewithfreshsolderpaste.锡膏氧化：更换新锡膏.9.Chip

wave

or

solder

wave

height

is

too

high

caused

excess

solder

to

top

side:adjustthe

wave

soldering

height

to

proper

level

(wavesolder).波峰高度设置的太高致使多余的焊锡到顶面：校正波峰焊设置到适当的高度(波峰焊接).FLEXTRONICSSolder

Ball/

锡珠30·is

s

not

wetted

to

the

land

or

termination

where

solder虚焊：需要焊接的引脚焊盘不润湿.·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半润湿：熔化的焊锡浸润表面后收缩，留下一焊锡薄层覆盖部分

区域，焊锡形状不规则.silofpnexthiedharrrequiSoldeNon-Wetting,Dewetting/虚焊，半润湿ofsolderthat

areseparated

by

areasthat

are

covered

with

atermination

type.FLEXTRONICS31Non-Wetting,Dewetting/

虚焊，半润湿1.Poor

solderability

of

component

or

pad./元件或焊盘可焊性太低Root

cause:a)Old

date

component

or

PCB./陈旧的元件或PCB

板b)Contamination

or

oxidation

on

component

or

PCB.

元件或焊盘污染或氧化Action:Purgethematerialforfurtherdisposition./清除来料2.The

paste

out

of

its

life

time:/锡膏超出有效期Scrapthe

lot

pasteand

replace

itwithfreshone报废有问题的锡膏，更换新锡膏FLEXTRONICS

32Cold

Solder/

冷

焊·

Incomplete

reflowofsolderpaste.

焊锡回流不完全FLEXTRONICS

33Countermeasure/对策1.Peaktemperature

istoo

loworreflowtime(dwell回流峰值温度太低或者回流时间不够：重设温度曲线图

.Typical

reflowprofile:/

典型的回流曲线ColdSolder/冷焊time)is

not

enough:Re-setup

the

profile

to

fulfill

thepaste

spec

or

customer

provided

spec.requirement.ttt

广CFLEXTRONICSmxmme(()34Time时间tc3

-large

SMD35tc1-small

SMDFLEXTRONICSToo

Hot!Too

Cold!Cold

Solder/

冷

焊Temp.

温度250℃230℃tc1-medium

SMDCold

Solder/

冷

焊Countermeasure/对策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盘遮挡造成该点峰值温度太低或回流时间不足：

对缺陷位置放大托盘的开口从而减少温差(△T).FLEXTRONICS

36Disturbed

Solder/

焊锡素乱·Disturbedsolder

jointcharacterizedbystress

linesfrommovementin

the

connection.在冷却时受外力影响，呈现紊乱痕迹的焊锡Countermeasure

/对策Check

and

adjust

the

cooling

airspeed

and

conveyor

status.检测调整冷却风速和传送带状态.

FLEXTRONICS37No

Solder/无锡No

soldertothe

land

orterminationwhere

solder

is

required.

焊点无锡FLEXTRONICS38Countermeasure/

对策1.Missingprinting/

漏印Root

cause:a)Stencil

aperture

was

jammed./钢网堵孔b)Highviscosityofsolderpaste./

锡膏粘性过高Action:a)Cleanstencil;/清洗钢网b)Replacethe

recycledpaste

with

fresh

one./更换新锡膏

c)Printing

machine

parameter

adjustment./校正丝印机参数2.Poor

solderability

of

component

or

pad./元件或焊盘可焊性太低

Root

cause:a)Old

date

component

or

PCB./陈旧元件或PCB板b)Contamination

on

component

or

PCB./元件或焊盘受污染

Action:Purge

the

material

for

further

disposition./清除来料3.Insufficient

flux

volume:increase

flux

spray

rate

(wave

solder).

助焊剂量不足：增加助焊剂喷射量(波峰焊接)4.Preheat

excess:lowerpreheat

temperature

properly(wave

solder).

预热过度：适当降低预热温度(波峰焊)5.Chip

wave

or

solder

wave

height

is

low:proper

height

(wave

solder).

波峰高度过低：调整到适当高度(波峰焊)FLEXTRONICSNo

Solder/无

锡39Insufficient

Solder/

少锡Insufficientsolder焊锡不足FLEXTRONICS40Countermeasure

/对策1.Stencil

aperture

clogging

cause

incomplete

solder

printing):Automatic

or

manual

clean

the

stencil.钢网孔堵塞导致锡膏不完全印刷：自动或者手工清洗钢网

i

a

ti

l

dp

c

l

e(Paste

height

under

LCL):锡膏量不足(锡膏高度在LCL以下):目检和Cpk

控制3.Solder

paste

print

misalignment:Fine

tune

printingmachine锡膏印刷偏位：校正丝印机使之最优4.Poor

solderability

of

component

or

PCB

pad:

元件或PCB焊盘可焊性差

a)Optimize

reflow

profile.优化回流曲线b)Exchange

the

poor

solderability

component.

更换掉低可焊性元件5.Excess

glue

or

glue

misalignment:Fine

tune

screen

print

(wave

solder).

点胶

过多或点胶偏位：优化丝印参数6.Less

flux:Increase

the

flux

spray

on

board

before

it

pass

wave

soldering(wave

solder).助焊剂不足：增加助焊剂的喷射量olmtrunoovktepsCanooschegpusoinnleuosNV2.Insufficient

Solder/

少

锡FLEXTRONICS

41·Solderfillet

extends

ontothe

top

of

the

component

body.

焊锡接触元件体.FLEXTRONICS42Excess

Solder/多锡Countermeasure/对策1.Excess

solder

paste:锡膏量过多a).Solder

paste

height

out

of

UCL:Adjust

printing

machine

to

control

the

paste

height.锡膏高度超出UCL:校正丝印机控制锡膏高度b).Nonstandard

of

stencil

aperture

opening:standardize

the

stencil

aperture

opening

fordifferenttypecomponents.钢网开孔不标准：为不同类型的元件设置相应钢网的开孔标准2.Wave

soldering/波峰焊接deag)a

nsvoel

i

3w~a5v

l

ring

time:Adjust

conveyor

ramp

angle

to

5~7传送带角度过小，波峰焊接时间变长：校正传送带角度到5~7度，焊接时间3~5秒b)High

preheat

temperature

to

dry

off

the

flux:According

to

flux

spec

to

control

the高预热温度造成助焊剂过度挥发：按照助焊剂的规格控制预热温度，通常，PCB表面温度

一般低于100℃FLEXTRONICSoocsseetnelomp,timganrrreencreeLowExcessSolder/多锡preheat

temperature,normally

the

PCB

surface

preheat

temperature

should

be

under100℃.43Wrong

Orientation/Polarity

反向，极性反Wrong

Polarity/极性反44CorrectPolarity/

正确的极性FLEXTRONICSWrong

Polarity:/极性反Anode

mark

onCorrect

Polarity/正确的极性Wrong

Polarity/

极性反Anode

mark

on

on

PCB.D503Cathode

mark

on

PCB.tantalum

capacitorCathode

mark

oncomponentbody.body.Wrong

Orientation/Polarity

反向，极性反WrongOrientation/反向：The

IC

is

populated

in

inversedirectiononthe

PCB.IC被反方向组装在线路板上FLEXTRONICS

45WrongOrientation/反向Correctdirection/正确的方向IC

direction

markon

PCB.IC

direction

markon

the

device

body.PBU014Countermeasure/对策1.Wrongplacementmachineprogram:Checkand

correctthe

machine

program.贴片机程序错误：检查和更正机器程序2.Manual

placement

in

reverse

direction:

手工放置元件错误a)Avoidmanualplacementcomponents

避免手工放置元件b)Need

special

inspection

for

the

manual

placement

prior

to

reflow(document

control).炉前需要特别检查那些手工放置的元件(文件控制)3.Disorderedorientation

inthetray/reelofthe

incomingmaterial:卷装或盘装来料元件的不规则放置.a)Inspectbefore

loading

ittoSMT.上料前检查来料b)Feedbacktovendortotakecorrectiveactions.反馈给供应商采取改善行动Wrong

Orlentation/Polarity

反向，极性反FLEXTRONICS46SolderHole/

锡洞·Blow

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

对策1.Insufficient

preheat:Reflow

profile

optimize.预热时间不足：优化回流曲线设置.2.Ramp

up

is

too

fast:Re-setup

the

reflow

profile

to

make

it

optimize.

升温速率太快：重设回流曲线图使之最优化.3.Excessfluxinsolderpaste:properlytoincrease

preheat

time

and

temperature.锡膏助焊剂含量过多：适当增加预热时间和温度值.4.Damp

PCB:Bakethe

PCBbefore

loading

ittoSMT.PCB受潮：SMT

组装前烘烤PCB板.5.Co

mponentfeetoxidation:Bake

itbeforeSMTorrequirevacuum

packing

on

incomingmaterial.元件脚氧