nRF焊接工艺要求 V11

Allrightsreserved.Reproductioninwholeorinpartisprohibitedwithoutthepriorwrittenpermissionofthecopyrightholder.December2006QFNSolderingReflowGuidelinesnAN400-08ApplicationNoteRevision1.1Page2of6ApplicationNoteLiabilitydisclaimerNordicSemiconductorASAreservestherighttomakechangeswithoutfurthernoticetotheproducttoimprovereliability,functionordesign.NordicSemiconductorASAdoesnotassumeanyliabilityarisingoutoftheapplicationoruseofanyproductorcircuitsdescribedherein.LifesupportapplicationsTheseproductsarenotdesignedforuseinlifesupportappliances,devices,orsystemswheremalfunctionoftheseproductscanreasonablybeexpectedtoresultinpersonalinjury.NordicSemiconductorASAcus-tomersusingorsellingtheseproductsforuseinsuchapplicationsdosoattheirownriskandagreetofullyindemnifyNordicSemiconductorASAforanydamagesresultingfromsuchimproperuseorsale.ContactdetailsForyournearestdealer,pleasesee’svei127004TrondheimPhone:[phone]Fax:[phone](leadfree)solderingreflowprofile.............................................6Revision1.1Page4of6ApplicationNote1IntroductionTheelectronicmanufacturingindustryismovingtowardsenvironmentallysafelead-free,orGreen,assem-blyprocesses.Factorsthatshouldbeconsideredwhenswitchingtolead-freesolderingmaterialsare:•Circuitboardthickness•Surfacefinish•Fabricationcomplexity•AssemblyprocesscompatibilityThisapplicationnotefocusesonsolderreflowrecommendationsforQFNpackageswithTin/LeadandMatteTin(Green)finishes.Note:Thewettingofthepackagesidewallisnotguaranteed.ThisisbecausetheQFNpackageisbydesigna“contactdown”package.Thesidewallsoftheleadsarenotplatedsincetheyareexposedbythesingulationstep,whichtakesplaceaftertheplating.Dependingonthesur-facestateofthebarecopperthesidewallsoftheleadsmaynotwetduringsoldering.PleaseseeFigure1.”TheQFNpackageisbydesigna“contactdown”package”.Figure1.TheQFNpackageisbydesigna“contactdown”packageRevision1.1Page5of6QFNSolderingReflowGuidelines2SolderreflowprocessbasicsLead-freesolderingprocesseshavebeenavailableforsomeyears.However,theydonotalwaysmeetthesamephysicalcriteriaforattachmentsassolderingalloyscontaininglead.Inthepast,themostcommonsolderingalloyforjoiningelectroniccomponentswasthemixtureof63%tinand37%lead.Thiscomposi-tionofTinandLeadprovidedexcellentbondingstrengthaswellasenoughelasticitytowithstandthether-malstressesintheproduct’soperatingenvironment.Aselectroniccompaniesbegantoreduceoreveneliminatetheleadalloycomponentintheirproducts,theseattributeswereoftenadverselyaffected.WerecommendusingthesolderprofilesshowninFigure2.”Recommendedreflowprofilefor63/37solderpasteforQFNwithtin/leadplating”andFigure3.”Recommendedsolderreflowprofileforlead-free(Green)solderpasteforGreenQFNpackages”forsolderingQFNpackages.However,factorssuchascir-cuitboardthickness,size,othersemiconductorpackages,passivecomponentsandreflowequipmentmayaffectthetotalprofiletime.2.1Tin/LeadSolderreflowprofileThetin/leadsolderreflowprocesstypicallyundergoesfourtransitionsasshowninFigure2.”Recom-mendedreflowprofilefor63/37solderpasteforQFNwithtin/leadplating”.•Heatingupfrom25to140°Catarateof1~3°C/sec.•Preheatat140-150°Cfor120~150seconds•Solderreflow.Rampuptemperatureat2-3°C/sectoapeaktemperatureof220-225°C.Tempera-tureover183°Cfor45~75sec.•Coolingdowntoroomtemperatureat2-4°C/sectoavoidundesiredintermetalliccompoundlayer.Figure2.Recommendedreflowprofilefor63/37solderpasteforQFNwithtin/leadplating0501001502002500306090120150180210240270300330360390420Time(s)Temperature(C)Revision1.1Page6of6ApplicationNote2.2Green(leadfree)solderingreflowprofileFigure3.”Recommendedsolderreflowprofileforlead-free(Green)solderpasteforGreenQFNpackages”showsthereflowrecommendationsforourGreenQFNpackages.AllgreenQFNpackageshavematteTinplating.TheSnAgCusolderpastewithameltingtemperatureof217°CisrecommendedfortheGreen(lead-free)reflowsolderingprocess.Thetin/leadsolderreflowprocesstypicallyundergoesfourtransitionsasshowninFigure3.”Recom-mendedsolderreflowprofileforlead-free(Green)solderpasteforGreenQFNpackages”.•Heatingupfrom25to160°Catarateof1~3°C/sec.•Preheatat155-165°Cfor120~150seconds•Solderreflow.Rampuptemperatureat2-3°C/sectoapeaktemperatureof240-245°C.Tempera-tureover217°Cfor40~60sec.•Coolingdowntoroomtemperatureat2-4°C/sectoavoidundesiredintermetalliccompoundlayer.Figure3.Recommendedsolderreflowprofileforlead-free(Green)solderpasteforGreenQFNpackages05010