ESD Control.docx

上传人:b****4 文档编号:11579098 上传时间:2023-03-19 格式:DOCX 页数:44 大小:203.79KB
下载 相关 举报
ESD Control.docx_第1页
第1页 / 共44页
ESD Control.docx_第2页
第2页 / 共44页
ESD Control.docx_第3页
第3页 / 共44页
ESD Control.docx_第4页
第4页 / 共44页
ESD Control.docx_第5页
第5页 / 共44页
点击查看更多>>
下载资源
资源描述

ESD Control.docx

《ESD Control.docx》由会员分享,可在线阅读,更多相关《ESD Control.docx(44页珍藏版)》请在冰豆网上搜索。

ESD Control.docx

ESDControl

Confidential

PeopleCommittedToInfoTech

 

ESDCONTROLPROGRAM

REVISION:

A

Date:

11/9/1999

PreparedBy:

______________________________

GyverLo

 

ApprovedBy:

______________________________

W.C.Wang

MITACINTERNATIONALCORP.

TAIPEIOFFICE:

8THFL.,NO.75,MINGSHENGE.RD.,SEC.3,TAIPEI,TAIWAN,R.O.C.TEL:

886-2-5018231TELEX:

11942TAIAUTOFAX:

886-2-5014265

FACTORY:

1,R&DROAD2.HSINCHUSCIENCE-BASEDINDUSTRIALPARK,HSINCHU,TAIWAN,R.O.C.TEL:

886-35-779250FAX:

886-35-776209

DOCUMENTCHANGESTATUS

REV

CHANGEDESCRIPTION

PREPARED

APPROVED

A

FirstRelease

GYVERLO

W.C.WANG

 

Contents

1ABSTRACT4

2REFERENCES5

3PROBLEMSTATEMENT6

4TEAMSTRUCTUREANDMEMBERLIST7

5ESDPROTECTIONEQUIPMENT9

6MEASURINGEQUIPMENT14

7ESDCONTROLCHECKINGITEMS16

8ESDCONTROLTRAININGPROGRAM21

9AUDITINGPROGRAM23

1ABSTRACT

ThisESDControlProgramestablishestheminimumrequirementsforElectrostaticDischarge

(ESD)controlmethodsandmaterialsusedtoprotectelectronicdevicesthataresusceptibleto

damageordegradationfromESD.Thepassageofastaticchargethroughanelectrostatic-

discharge-sensitive(ESDS)devicecanresultincatastrophicfailureorperformancedegradationof

thepart.

Inthefollowingsections,weimplementseveralESDprotectiveequipmentandsomemeasuring

equipmenttomaintaintheirfunctions.AlsoweimplementESDcontroltrainingprogramandESD

auditprogramtostrengthenandcheckourexecutionofESDControlProgram.However,the

effectivenessshouldbereliedonexactimplementationandpromptcorrectiveactions.

2REFERENCES

2.1WorkmanshipSpecificationforESDControlDocument,A-5951-1589-1,

RevisionH,ESDProgram,HPCorporate,1999.

2.2RequirementsforHandlingElectrostatic-Discharge-Sensitive(ESDS)Devices,

EIA-625,EIAStandard,EIA,1994.

2.3BasicsofElectrostaticDischarge,ESDAssociation,1998.

2.4ProtectionAgainstElectrostaticDamage,Sharp,1995.

2.5ESD/EOSFundamentalandAvoidance,INTEL,1996.

2.6靜電防制專業工程師訓練課程講義,工業技術研究院電子所,1999.

3PROBLEMSTATEMENT

AccordingtoStephenHalperin(GuidelinesforStaticControlManagement,Eurostat1990),averageproductlossesduetostaticrangefrom8%to33%(seeTable1).OthersestimatetheactualcostofESDdamagetotheelectronicsindustryasrunningintothebillionsofdollarsannually.Thecostofdamageddevicesthemselvesrangesfromonlyafewdollarsforasimplediodetoseveralthousanddollarsforcomplexhybrids.Whenassociatedcostsofrepairandrework,shipping,labor,andoverheadareincluded,clearlytheopportunitiesexistforsignificantimprovements.

ESDdamagetoelectroniccomponentsandassemblieshasbeenamajorproblemoftheelectronicsindustryinrecentyears,orinstallingESDsensitivedevices.Devicesthataren'tdestroyedduringhandlingareoftendamagedorimpaired.Thisdamageisknownas"latent"damageandoftenisnotdetectablebyroutinequalitytests,andcouldappearafterthedeviceisinstalledinitshostequipment.

Anelectrostaticchargealsomaybecreatedonamaterialinotherwayssuchasbyinduction,ionbombardment,photoelectriceffect,particlebeam,freezing,radioactivedecay,spray,fieldemissionorcontactwithanotherchargedobject.However,triboelectricchargingisthemostcommon.Table2showssomeexamplesthatcangeneratedifferentvoltagelevelsofelectrostaticcharges.

Table1

InformalSummaryof

StaticLossesbyLevel

StaticLossesReported

Description

Min

Loss

Max

Loss

Est.Avg.

Loss

Component

Manufacturers

4%

97%

16-22%

Subcontractors

3%

70%

9-15%

Contractors

2%

35%

8-14%

Users

5%

70%

27-33%

Source:

StephenHalperin."GuidelinesforStaticControlManagement"Eurostat1990.

Table2

ExamplesofStaticGeneration

TypicalVoltageLevels

MeansofGeneration

10-25%RH

65-90%RH

Walkingacrosscarpet

35,000V

1,500V

Walkingacrossvinyltile

12,000V

250V

Workeratbench

6,000V

100V

Polybagpickedupfrombench

20,000V

1,200V

Chairwithurethanefoam

18,000V

1,500V

4TEAMSTRUCTUREANDMEMBERLIST

4.1Structure

4.2MemberList

Position/DepartmentMission

Chairman/QAResponsibleforMiTAC'sESDcontrolprogram

Coordinator/QEDevelop,implementandmaintainESDcontrol

program

AuditController/IPQAResponsiblefortheauditingprogram

IQCResponsibleforIQC'sESDcontrolprogram

SMTlineResponsibleforSMT'sESDcontrolprogram

PCBAproductionlineResponsibleforPCBAproductionline'sESDcontrol

program

SystemassemblylineResponsibleforSystemassemblyline'sESDcontrol

program

WarehouseResponsibleforWarehouse'sESDcontrolprogram

OQAResponsibleforOQA'sESDcontrolprogram

MODResponsibleforMOD'sESDcontrolprogram

EngineeringDivisionAssisttheproductionlinetoexecuteandmaintain

theESDcontrolprogram

4.3ScheduleofTeamMeetings

4.3.1ThefirstESDControlmeetingwillbeheldat10:

10AM,Friday,5Nov99.

4.3.2ThesecondmeetingwillbeheldonThursday,Dec9,1999.

4.3.3ThethirdmeetingwillbeheldonThursday,Jan6,2000.

4.3.4Afterwards,meetingsshallbeheldquarterly.

5ESDPROTECTIONEQUIPMENT

5.1ESDWristStrapsandGloves

Typically,theprimarymeansofcontrollingstaticchargeonpersonneliswithawriststrap

andapairofgloves.Whenproperlywornandconnectedtoground,awriststrapkeepsthe

personwearingitneargroundpotential.Becausethepersonandothergroundedobjectsinthe

workareaareatornearthesamepotential,therecanbenohazardousdischargebetween

them.Inaddition,staticchargesaresafelydissipatedfromthepersontogroundanddonot

accumulate.Wriststrapshavetwomajorcomponents,thecuffthatgoesaroundtheperson's

wristandthegroundcordthatconnectsthecufftothecommonpointground.Mostwrist

strapshaveacurrentlimitingresistormoldedintothegroundcordheadontheendthat

connectstothecuff.Theresistormostcommonlyusedisa1MΩ,1/4Wwithaworking

voltageratingof250V.Theresistancefromawriststrapwearer'shandtogroundshallbe

~Ω.

5.2Shoes,HeelStraps

UsedincombinationwithESDprotectivefloormaterials,staticcontrolshoes,grounders,

castersandwheelsprovidethenecessaryelectricalcontactbetweenthepersonorobjectand

thefloormaterial.Insulativefootwear,castersorwheelspreventstaticchargesfromflowing

fromthebodytothefloortoground.Theresistancefromfingertiptogroundisthesameas

wriststrap.

5.3Smocks

Clothingmaterialscangenerateelectrostaticchargeswhentheycontactandseparatefrom

otherobjectsandtheclothingitself.Thesechargesmaydischargeintosensitivecomponents

orcreateelectrostaticfieldsthatmayinducechargesonthehumanbody.Althoughaperson

maybegrounded,thatdoesnotmeanthatinsulativeclothingfabricscandissipateachargeto

thatperson'sskinandthentoground.Clothingusuallyiselectricallyinsulatedorisolated

fromthebody.Staticcontrolgarmentsareintendedtominimizetheeffectsofelectrostatic

fieldsorchargesthatmaybepresentonaperson'sclothing.Smockssleevetosleeve

resistanceshouldbebetweenandΩafter20washings.

5.4WorkStationsandWorksurfaces

WorksurfacesandworkstationsareimportantpartsofanESDprotectiveprogram.Many

ESDSdevicesandassembliesarehandled,assembledorrepairedatworkstations.Thework

stationprovidesameansforconnectingallworksurfaces,fixtures,handlingequipment,and

groundingdevicestoacommonpointground.ThekeyESDcontrolelementscomprising

mostworkstationsareastaticdissipativeworksurface,ameansofgroundingpersonnel

(usuallyawriststrap),acommongroundingconnection,andappropriatesignageand

labeling.StaticprotectiveworksurfaceswitharesistancetogroundoftoΩ

provideasurfacethatisatthesameelectricalpotentialasotherESDprotectiveitemsinthe

workstation.Theyalsoprovideanelectricalpathtogroundforthecontrolleddissipationof

anystaticpotentialsonmaterialsthatcontactthesurface.Theworksurfacealsohelpsdefinea

specificworkareainwhichESDsensitivedevicesmaybesafelyhandled.Theworksurfaceis

connectedtothecommonpointground.

5.5ESDDissipativeChairs

ESDchairsshallbeconstructedofstaticdissipativematerials.Theresistancefromtheseat

cushion,backorarmreststogroundshallcontinuouslybewithintherequiredrangeofto

Ω.

5.6Ionizers

Aswehaveseen,theprimarymethodofstaticchargecontrolisdirectconnectiontoground

forconductors,staticdissipativematerials,andpersonnel.However,acompletestaticcontrol

programmustalsodealwithisolatedconductorsthatcannotbegrounded,insulatingmaterials

(e.g.,mostcommonplastics).Topicalantistatsoftenareusedtodissipatestaticchargesfrom

theseitemsundersomecircumstances.Morefrequently,however,airionizationcan

neutralizethestaticchargeoninsulatedandisolatedobjectsbychargingthemoleculesofthe

gasesofthesurroundingair.Whateverstaticchargepresentonobjectsinthework

environmentwillbeneutralizedbyattractingoppositepolaritychargesfromtheair.Because

itusesonlytheairthatisalreadypresentintheworkenvironment,airionizationmaybe

employedevenincleanroomswherechemicalspraysandsomestaticdissipativematerials

arenotusable.Airionizationisnotareplacementforgroundingmethods.Itisonecomponent

of

展开阅读全文
相关资源
猜你喜欢
相关搜索

当前位置:首页 > 人文社科

copyright@ 2008-2022 冰豆网网站版权所有

经营许可证编号:鄂ICP备2022015515号-1