IPC-4761-via-type

TypeCatDescriptionfigureprocessRemarkII-aTentedViaTentedVia(TypeIVia):Aviawithadryfilmmaskmaterialappliedbridgingovertheviawhereinnoadditionalmaterialsareinthehole.Itmaybeappliedtooneside(TypeI-a)orbothsides(TypeI-b)oftheviastructure.Process:Vacuumlaminatedfilmmaterialthatisphoto-definable.SingleSidedTentedNotRecommendedII-bTentedViaIIII-aTentedandCoveredViasATypeIviawithasecondarycoveringofmaskmaterialappliedoverthetentedvia.Thematerialmaybeappliedtooneside(TypeII-a)orbothsides(TypeII-b)oftheviastructure.Process:ApplicationofmaskoverTypeI.SingleSidedTentedandCoveredNotRecommendedIIII-bTentedandCoveredViasIIIIII-aPluggedViaAviawithmaterialappliedallowingpartialpenetrationintothevia.Theplugmaterialmaybeappliedfromeitheroneside(TypeIII-a)orbothsides(TypeIII-b)oftheviastructure.Process:ScreenedandRollerCoated.SingleSidedPluggedNotRecommended.IIIIII-bPluggedViaIVIV-aPluggedandCoveredViaATypeIIIviawithasecondarycoveringofmaterialappliedoverthevia.Theplugandsecondarycoveringmaterialmaybeappliedfromeitheroneside(TypeIV-a)orbothsides(TypeIV-b)oftheviastructure.Process:ApplicationofmaskoverTypeIII.SingleSidedPluggedandCoveredNotRecommendedIVIV-bPluggedandCoveredViaVVFilledViaAviawithmaterialappliedintotheviatargetingafullpenetrationandencapsulationofthehole.Process:Screened,roller-coated,orsqueegeed.VIVI-aFilledandCoveredViaDryFilmCoverATypeVviawithasecondarycoveringofmaterial(liquidordryfilmsoldermask)appliedoverthevia.Thecoveringmaterialmaybeappliedfromeitheroneside(TypeVI-a)orbothsides(TypeVI-b)oftheviastructure:Process:ApplicationofmaskoverTypeV.Fillmaterialcanbeelectricallyand/orthermallyconductivedependingonenduse.VIVI-bFilledandCoveredViaDryFilmCoverVIVI-aFilledandCoveredViaLiquidFilmCoverVIVI-bFilledandCoveredViaLiquidFilmCoverVIIVIIFilledandCappedViaATypeVviawithasecondarymetallizedcoatingcoveringthevia.Themetallizationisonbothsides:Process:MetallizedcoatingoverTypeV.Applicablewherehighdensityfeaturesarerequired.PartiallyFilledViaThoughnotidentifiedasaviaprotectiontype,thisdocumentdoesrecognizemanufacturingprocesseswheresoldermaskflowsintotheholeduringliquidsoldermaskapplication,withoutintendingtoprovidecompletecoverageorprotection,andmayresultinpartialplugging.Thisisnotacceptablewithbarecoppersurfacefinishes.Theillustrationsbelowshowtypicalviaconfigurationswhenliquidsoldermaskisusedwithnospecificprocessforviaprotection.Inconsistencyofcoveragecanleadtoamixofallconfigurationsonthesameboard.Processshouldnotbeimplementedoverbarecopper.IfthefinalfinishisHASLthecenteroftheholewallwillbebarecopper.