Chemical gold ENIG (Electroless Nickel Immersion Gold)

New environmental standards have conducted the PCB industry into new directions. The inevitable result took shape in more innovative challenges. Still, the continuously evolving advanced technologies prescribes smaller pads, higher signal frequencies, controlled impendence, etc…

Widely the ENIG finish is regarded through history as the best lead-free solder finish for fine pitch applications because of its planar surface.  ENIG has a build-up of 5 micron nickel and 0,05 – 0,1 micron of gold. The applied layer of gold is porous and cannot fully protect the copper against oxidation, therefore an under layer of electroless nickel acts as a barrier and in addition to avoid and prevent the spreading of copper. Also because of the low temperature applied while manufacturing such prints, there is less chance of curving or bending.

ENIG is a sophisticated complicated system which has many advantages:

• Excellent wettability.
• Excellent re-flow cycles.
• Very good molecular attraction.
• Long shelf-life.
• Outstanding electrical testability.
• Great solderability.
• Keeps planarity of the copper.
• Consistent thickness.
• Withstands multiple cycles.

ENIG is very versatile. It is aluminium wire bondable and allows easy visual inspection.