Printed circuit board surfaces

The circuit board surface is responsible for raising the wetting ability of the contact areas for soldering; non-chemical surfaces serve simultaneously as protection against oxidation of the covered copper and improve shelf life characteristics. 

The circuit board surfaces vary in shelf life, typical application field and price, but are normally specified by the process, product or desired location for the application.

Available surfaces

Surface PCB RoHS-compliantRoHS-compliant PCB solderingSoldering PCB Bonding aluminium wireBonding aluminium wire PCB Bonding gold wireBonding gold wire PCB BGABGA PCB Flex-/Rigid-FlexFlex-/Rigid-Flex PCB PressfitPressfit PCB PCI contactsPCI contacts PCB sliding contactSliding contact PCB surface thicknessThickness PCB shelf lifeShelf life PCB Reflow CyclesReflow Cycles
SurfaceHal SnPbPCB RoHS-compliantRoHS-compliant PCB solderingSolderingcheckPCB Bonding aluminium wireBonding aluminium wire PCB Bonding gold wireBonding gold wire PCB BGABGA PCB Flex-/Rigid-FlexFlex-/Rigid-Flex PCB PressfitPressfitcheckPCB PCI contactsPCI contacts PCB sliding contactSliding contact PCB surface thicknessThickness>5µmPCB shelf lifeShelf lifeca.12 monthsPCB Reflow CyclesReflow Cycles5
SurfaceHAL lead-freePCB RoHS-compliantRoHS-compliantcheckPCB solderingSolderingcheckPCB Bonding aluminium wireBonding aluminium wire PCB Bonding gold wireBonding gold wire PCB BGABGA PCB Flex-/Rigid-FlexFlex-/Rigid-Flex PCB PressfitPressfitcheckPCB PCI contactsPCI contacts PCB sliding contactSliding contact PCB surface thicknessThickness>5µmPCB shelf lifeShelf lifeca. 12 monthsPCB Reflow CyclesReflow Cycles5
SurfaceChemical tinPCB RoHS-compliantRoHS-compliantcheckPCB solderingSolderingcheckPCB Bonding aluminium wireBonding aluminium wire PCB Bonding gold wireBonding gold wire PCB BGABGA PCB Flex-/Rigid-FlexFlex-/Rigid-Flex PCB PressfitPressfitcheckPCB PCI contactsPCI contacts PCB sliding contactSliding contact PCB surface thicknessThickness>1µmPCB shelf lifeShelf lifeca. 6 monthsPCB Reflow CyclesReflow Cycles5
SurfaceChemical silverPCB RoHS-compliantRoHS-compliantcheckPCB solderingSolderingcheckPCB Bonding aluminium wireBonding aluminium wirecheckPCB Bonding gold wireBonding gold wire PCB BGABGA PCB Flex-/Rigid-FlexFlex-/Rigid-Flex PCB PressfitPressfitcheckPCB PCI contactsPCI contacts PCB sliding contactSliding contact PCB surface thicknessThickness0.2 - 0.3µmPCB shelf lifeShelf lifeca. 12 MonatePCB Reflow CyclesReflow Cycles5
SurfaceChemical gold
ENIG
PCB RoHS-compliantRoHS-compliantcheckPCB solderingSolderingcheckPCB Bonding aluminium wireBonding aluminium wirecheckPCB Bonding gold wireBonding gold wire PCB BGABGAcheckPCB Flex-/Rigid-FlexFlex-/Rigid-FlexcheckPCB PressfitPressfitcheckPCB PCI contactsPCI contacts PCB sliding contactSliding contact PCB surface thicknessThickness3-6µm Ni
0.025-0.1µm Au
PCB shelf lifeShelf lifeca. 12 monthsPCB Reflow CyclesReflow Cycles5
SurfaceENEPIGPCB RoHS-compliantRoHS-compliantcheckPCB solderingSolderingcheckPCB Bonding aluminium wireBonding aluminium wirecheckPCB Bonding gold wireBonding gold wirecheckPCB BGABGAcheckPCB Flex-/Rigid-FlexFlex-/Rigid-Flex PCB PressfitPressfitcheckPCB PCI contactsPCI contacts PCB sliding contactSliding contact PCB surface thicknessThickness3-8µm Ni
0.05-0.15µm Pd
0.05-0.1µm Au
PCB shelf lifeShelf lifeca. 12 monthsPCB Reflow CyclesReflow Cycles-
SurfaceGalvanic softgoldPCB RoHS-compliantRoHS-compliantcheckPCB solderingSolderingcheckPCB Bonding aluminium wireBonding aluminium wire PCB Bonding gold wireBonding gold wirecheckPCB BGABGA PCB Flex-/Rigid-FlexFlex-/Rigid-Flex PCB PressfitPressfit PCB PCI contactsPCI contacts PCB sliding contactSliding contact PCB surface thicknessThickness4 - 6µm Ni
>1µm Au
PCB shelf lifeShelf lifeca. 12 monthsPCB Reflow CyclesReflow Cycles-
SurfaceGalvanic hardgoldPCB RoHS-compliantRoHS-compliantcheckPCB solderingSoldering PCB Bonding aluminium wireBonding aluminium wire PCB Bonding gold wireBonding gold wire PCB BGABGA PCB Flex-/Rigid-FlexFlex-/Rigid-Flex PCB PressfitPressfit PCB PCI contactsPCI contactscheckPCB sliding contactSliding contactcheckPCB surface thicknessThickness4 - 6µm Ni
0.1 - 2µm* Au
PCB shelf lifeShelf lifeca. 12 months
on request
PCB Reflow CyclesReflow Cycles-
PCB surface HAL SnPb

HAL SnPb

HAL SnPb (lead-tin) is nowadays allowed only in certain technology fields such as medicine and space travel. HAL is suitable for standard SMD, but shows weaknesses in fine pitch applications. A chemical surface is preferable for finepitch (see also HAL vs.  chemical gold).

Advantages:

  • Good solderability
  • Good reflow properties

    Disadvantages:

      PCB surface HAL leadfree

      HAL lead-free

      HAL (Hot Air Levelling) is a well-proven method to apply tin as circuit board surface. Every assembler should be able to process circuit boards with HAL surfaces without any problem. HAL is suitable for standard SMD, but exhibits some weaknesses for finepitch applications, for which a chemical surface should be preferred (see also HAL vs.  immersion gold).

      Advantages:

      • Good solderability
      • Good reflow properties

      Disadvantages:

      • Pads are non-planar
      PCB surface chemical tin (immersion tin)

      Chemical tin

      The surface chemical tin is for manufacturing reasons rarely requested any more! Due to the rapid oxidation of the copper, the shelf life is highly dependent on temperature and packaging. Fingerprints on the surface should be avoided at all.

      Advantages:

      • Absolutely flat
      • Good for fine pitch
      • Good for SMD
      • Good for press-fit

      Disadvantages:

      • Extra charge
      • Critical manufacturing process
      • Faster oxidation, thus limited storability
      PCB surface chemical silver (immersion silver)

      Chemical silver

      This circuit board surface is very similar to chemical tin, with better properties for oxidation and contact applications. The surface is very flat and therefore suited very well for finepitch.

      Advantages:

      • Absolutely flat
      • Good for fine pitch
      • Good for SMD
      • Good for press-fit
      • Better shelf life than chemical tin

      Disadvantages:

      PCB surface chemical gold (ENIG)

      Chemical gold (ENIG)

      Just as with chemical tin and chemical silver, chemical gold is an extremely flat circuit board surface, and has very good oxidation properties. It is perfectly suited for finepitch and bonding (aluminium wire) applications. Due to popular demand, Multi-CB can offer chemical gold in pooling service (cheaper price). Chemical gold is also called ENIG (Electroless Nickel Immersion Gold).

      Advantages:

      • Absolutely flat
      • Very good for fine pitch
      • Very good for SMD
      • Very good wetting characteristics
      • Good for press-fit
      • Good storability
      • Available in Pool-Service

      Disadvantages:

      • Possible extra charge
      PCB surface ENEPIG

      ENEPIG

      ENEPIG (Electroless Nickel Electroless Palladium Immersion Gold) is extremely planar and has very good oxidation properties. It is ideally suited for soldering applications and aluminum wire bonding / gold wire bonding.

      Advantages:

      • Absolutely flat
      • Very good for alu-wire-bonding
      • Very good for gold-wire-bonding
      • Very good for fine pitch, SMD
      • Very good wetting characteristics
      • Good storability

      Disadvantages:

      • Extra charge