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
*Compatability with variety of fluxes & paste
Available Surface Finishes
*Electroless Nickle-Immersion Gold
*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 finish
plated onto the copper base by means of a
chemical decomposition process.
|*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