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ID:58988879
大小:2.60 MB
页数:37页
时间:2020-09-27
《静电防护设计原理与方法ppt课件.ppt》由会员上传分享,免费在线阅读,更多相关内容在教育资源-天天文库。
1、第11讲静电防护设计原理与方法1静电防护设计原理与方法11.1元器件防护设计11.2印制电路板组件防护设计11.3电子整机系统的防护设计211.1元器件防护设计输入端的防护设计3DesignConceptsWillshuntmostorallofthecurrentduringanESDeventCanbe:athickfieldtransistorasiliconcontrolledrectifier(SCR)anMOStransistorasimplepndiodeServestolimitthevoltageor
2、currentatthecircuitbeingprotectuntiltheprimarydeviceisfullyoperational.Canbe:asmallgroundedgateMOStransistoradiodebetweenthepadsandthepower/groundsuppliesCanbe:polysiliconn+diffusionp+diffusionn-well4ThickFieldDevice--thickoxideorfieldoxidedevice(FOD)--usedforte
3、chnologieswithfeaturesizes(rangingfrom3µmto1µm)ThreeDifferentcross-sections5MainDesignParametersoftheFODHBMfailurethresholdsincreaseasthechannellengthisdecreasedinthe7µmto2µmrange6DraincontactIncreased-saturate:reason:distancebetweentheheatsourceandthecontact(co
4、ntactclosetodiffusionedge—theproducedheatspreadtoheatthecontactmetalization—resultinalowerfailurevoltage)Impactofthecontactspacing:veryimportantfortheabruptjunctionprocesses,weakeffectforlightlydopeddrain(LDD)theeffectvirtuallyvanishesforsilicideprocessImproveth
5、ehotcarrierreliability7nMOSTransistors(FPDs)essentiallythinoxidedevicesasopposedtotheFODarealsocalledfield-plateddiodesorgated-diodesusedasaprimaryprotectiondevice,intechnologieswithfeaturesizesgreatedthan1µmnonsilicidedtechnologyturnaroundintheESDperformanceoft
6、henMOSdeviceatthe0.8µmtechnologynodefornon-silicideddevicesatthe1µmtechnologynodeforsilicideddevice8MaindesignparametersofnMOSandlayoutthetransistorchannellength(L)draincontact-to-gatespacing(DCG)thedevicewidth(notshown)Thesourcecontact-to-gatespacing(SCG)(notpl
7、aymuchofarole,oftenkeptatitsminimumdesignvalue.RFiscomposedofmetalfingerresistanceContactresistanceDiffusionsheetresistanceRs(parasiticresistance):AssociatewiththegroundbusthatconnectsthefingersofthedeviceMaintainingaminimumrateforRs/RFisimportantforobtainingthe
8、bestpossibleESDperformance.minimizingRswillgivemoreuniformcurrentdistribution9HBMESDperformanceinFPDsasafunctionofDCGdraincontactspacinghasalargeeffectfornonsilicided
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