底充胶吸湿特性与其对无铅倒装焊焊点可靠性的影响

《底充胶吸湿特性与其对无铅倒装焊焊点可靠性的影响》由会员上传分享，免费在线阅读，更多相关内容在学术论文-天天文库。

1、桂林电子科技大学学位论文AbstractThepolymerscommonlyusedinplasticelectronicpackagingareapttoabsorbmoistureintheenvironment,whichgreatlya®ectsthereliabilityofpackages.Atpresent,thereliabilityanalysisunderthein°uenceofmoisturemainlyfocusesonthewholeplasticencapsulateddevice,littleonsolderjointsthatarethemainfact

2、orinduc-ingthefailureofelectronicassembly.Inthisdissertation,epoxyunder¯llandlead-free°ipchipsolderjointsin°ipchiponboard(FCOB)arechosenastheresearchob-ject.Themoisturedistributioninunder¯llunderdi®erentmoisturepreconditioningisstudiedanditsa®ectsonthereliabilityoflead-free°ipchipsolderjoints.Them

3、ainresearchcontentisasfollows:1.Aprogrammablesymmetricalgravimetricanalyzer(SGA-100)isusedformois-tureabsorptionexperimentofunder¯ll.Thesaturatedmoisturecontentandmoisturedi®usionconstantofunder¯llareobtainedatdi®erenttemperatureandhumidity.TheconstitutivemodelofcreepisputforwardbySchuberttodescri

4、becreepdeformationofSn95.5Ag3.8Cu0.7solderjoint,andthelifepredictionmodeloflead-freesolderjointsisestablishedbasedoncreepdeformation.2.Themoisturedistributioninunder¯llundervariousmoisturepreconditioningissimulatedbasedonathree-dimensional¯niteelementmodelofFCOBdevice.Andmoisturedi®usionandthermal

5、cyclingdesorptioninunder¯llarecontrastedandana-lyzedbyjointelectrondeviceengineeringcouncil(JEDEC)makingmoisturesensitivitylevels(MSL-1)whichrelatetomoisturesensitivecomponents.3.Thermalstressandstraininlead-free°ipchipsolderjointsareanalyzedunderthethermalcyclingloading.Thenfurtherhygromechanical

6、andthermomechanicalstressareintegrated.Thee®ectsofhotandhumidenvironmentonthereliabilityoflead-free°ipchipsolderjointsareestablished.Andfatiguelifeoflead-freesolderjointsispredictedrespectivelyundertheconditionofthermalandhygrothermalstress.Finally,thee®ectsofthermalandhygrothermalstressontherelia

7、bilityoflead-freesolderjointsarecontrastedandanalyzed.Theresearchresultsnotonlyhavesomeguidancesigni¯cancetointegratedpack-agingandapplicationprocessofplasticencapsulatedelectroniccomponentsindi®erenthumidenviron