湿热载荷下无铅焊点电阻应变分析

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1、中南大学硕士论文ABSTRACTThereliabilityoflcad．freesolderiointscontinuestoremainamajorconcernasthepopularityoflead—freesolder．So，allkindsofreliabilityexperimentsoflead．freesolderjointsareraisedaccordingly．Electroniccomponentsareinfluencedbytemperatureandhumidityatthesametimeintheactu

2、alenvironment．Temperatureandhumidityconstituteahighproportioninthefailurecauseofsolderioints，SOreliabilityaboutsolderjointsconsiderationwhichisintheenvironmentoftemperatureandhumidityisnecessary．Firstly,thispapersummarizessituationoflead—freesolderjointsreliabilitystudy，ana

3、lyzestheimportanceoflead—freesolderjointsreliabilitystudy,overviewsmeaningsandsituationofstudyaboutlead．freesolderiointsreliabilityunder也eloadoftemperatureandhumidity,analyzesfeasibilityofaelectricalmeasurementmethodaboutlead．freeiointsreliabilityandsituationofstudyonelectr

4、icalmeasurement．Failuremechanismoflead．freesolderioints(SnAgCu)hasbeenresearchedinthecircumstanceoftemperatureandhumidityloadalone，andcombinedaction．Accordingtofailuremechanismoftheexposedlcad．freesolderiointsunderthecombinedactionoftemperatureandhumidity,simplemodelofinval

5、idationsolderjointswasbuiltandrelationexpressionbetweendamageofsolderjointsandresistancestrainwasdeduced．ItprovidesfundamentalbasisforcharacteristicresearchofSnAgCusolderjointsresistancestrainundertheloadoftemperatureandhumidity．Onthefoundationofformertestsystemofmicro．resi

6、stance，testsystemofsolderjointswasdesignedtomeasureresistanceintheenvironmentoftemperatureandhumidity．Four-probemethodinmicro．resistancemeasurementhasbeenreplacedbyfive—probedifferencemethodwhichisprecisethroughexperimentalproofinthepaper．Inthisarticle，withSnAgCusolderjoint

7、sspecimens(thewidthandlengthislmm，differentthickness)，fivekindsofexperimentshavebeenperformedbyfive—probedifferencemethod，includinghigh—lowthermalshockcycletestwithlowhumidity,hightemperaturecyclewithlowhumidity,hightemperatureconstant，humiditycycleunderlowtemperatureandhum

8、iditycycleundermediumtemperatureconstant．Alotofsolderspecimens’testingresultshaveb