What is the ENIG process?
The full name of ENIG is Electroless Nickel/Immersion Gold, abbreviated ENIG, and Chinese is called chemical nickel gold, nickel nickel or nickel nickel. It is a kind of PCB manufacturing welding surface treatment process.
The process of the ENIG process (chemical nickel/immersion gold) is as follows:
(1) Clean the copper surface.
(2) Micro-etched copper surface.
(5) Electroless nickel plating (EN) at 79 to 85 °C.
(7) Electroless gold plating (Im-Au) at 85 to 91 °C.
What are the advantages of the ENIG process for printed circuit board manufacturing?
Advantages: (1) The plating layer is suitable for high density pad design.
(2) The solderability of the board is good
(3) Flux compatibility is good.
(4) The storage period of the board is long.
(5) Low contact resistance.
(6) The coating has good wear resistance.
Disadvantages: (1) can not be reworked.
(2) The “Black Pad” phenomenon poses a threat to the reliability of BGA solder joints.
(3) The welding strength is unstable, depending on the thickness and porosity of the gold layer.
(4) The coating has a high porosity, which makes the corrosion resistance worse.
(5) Gold makes the solder joint surface brittle, which affects reliability.
(6) The ENIG process uses many highly corrosive chemicals and is aggressive against most solder resist inks and white inks.