Purpose of PCB Surface Finish

*Provides a solderable surface for Component assembly.

*Protect Copper Surface from Oxidation.

*Provide a surface appropriate for wear related parts.


High Performance Surface Finish

*Mixed Technology Board Designs

*Solderable,SMT and Thru-hole

*Wire Bondable

*Contact Resistance

*Co-Planar Surfaces

*Compatability with variety of fluxes & paste

*Cost effective



Available Surface Finishes

*Electroless Nickle-Immersion Gold

*Immersion Silver

*Hot Air Solder Level

*Organic Solderability Preservative

*Electrolyte Nickel – Hard Gold

*Electrolyte Nickel – Soft Gold


Surface Finish Details

*Electroless Nickel-Immersion Gold (ENIG)


A two layer, gold over nickel, metallic surface finish1

plated onto the copper base by means of a

chemical decomposition process.




 Advantage:                                                    Disadvantage:                                   

*Typical Thickness: 3-8 uin gold over 150-250 *Narrow process window
uin nickel *Higher cost than HASL(1.5 to 2.0 times)
*Excellent Corrosion resistance *Back pads: brittle solder joints
*Good for aluminium wire bonding *Fatigue failures on large BGA packages
*Excellent flatness for fine-pitch technology *Skip plate
*Excellent Solderability *Extraneous nickel plating
*Excellent shelf life(12 mo) *Solder mask capability with the nickel bath
*Good surface contrast
*Good contact resistance
*High Aspect Ratio Capability