PCBA for non-contact infrared thermometer

What is ENIG?

Apr 23, 2021

ENIG full name is Electroless Nickel/Immersion Gold(some people call Chemical nickel gold, immersion nickel gold and soft gold)
It is a continuous layer of nickel-gold alloy deposited on the surface of copper through redox reaction, a process of applying solderable coating on the bare copper surface of the PCB, which makes the PCB have better electrical conductivity and prolongs the service life of the PCB. Sometimes the cost of this surface treatment process will account for 20% of the cost of the printed circuit board. In actual production applications, 90% of the gold plates use the process of ENIG. After this process, the color of the PCB surface is stable to golden yellow,the brightness is good, the plating layer is flat, and the thickness of the surface treatment as the pad is generally 0.03µ - 0.08 µ. In the same way, gold finger PCB is made. Compared with the Gold Plating process, the gold finger of ENIG is not wear-resistant.If you do not often plug and unplug the Golden finger , you can also choose ENIG Process.
At present, about 10%-20% of PCBs surface treatment use ENIG. The first choice for the button PCB, suitable for the edge connection area of the router shell and the electrical contact area for elastic connection of the chip processor, high-precision PCB with bonding IC, or BGA design.

ENIG makes the welding surface flat and can be well welded. Compared with Gold Plating, it has a lower cost and can prevent corrosion on the exposed copper surface.
a). PCB surface is flat, good coplanarity
b). The solderability is good, and the soldering of the components is stronger (over reflow soldering will not affect its solderability)
c). It is not easy to be oxidized and anti-corrosion, so that the PCB can be stored for a longer time
a). Compared with Gold Plating, the ENIG process is not wear-resistant
b). Compared with the OSP process, the ENIG process is complicated
General ENIG process:
Acid cleaning→micro-etching→pre-dipping→activation→electroless nickel plating→chemical immersion gold.
Comparison of ENIG and Plating Gold:

Outward Appearance


Antioxidant capacity

Solder mask

Binding force

Plating Gold

Bias towards white





Bias towards yellow




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