Gold is applied to the surface treatment of PCB board because gold has strong conductivity, good oxidation resistance and long life. Generally, it is applied to key board, gold finger PCB, etc. The most fundamental difference between ENIG and gold plated is that gold plating is hard Gold (abrasion resistant), immersion gold is soft gold (not wear resistant).The detail as follows:
1. The crystal structure formed by immersion gold and gold plating is different. The thickness of gold is much thicker than that of gold plating. The gold is golden yellow, which is more yellow than gold plating. This is the method of distinguishing gold plating and gold immersion, gold plating will be slightly white (nickel color).
2. The crystal structure formed by immersion gold and gold plating is different. The immersion gold is easier to weld than gold plating, and will not cause poor welding. The stress of the immersion gold plate is easier to control, and it is more conducive to the processing of the bond for the bonding products. At the same time, because immersion gold is softer than gold plating, the gold is not wearable (the disadvantage of immersion gold).
3. The immersion gold board only has nickel gold on the pads. The signal transmission in the conductor skin effect is not affected by the signal in the copper layer.
4. Compared with gold plating, immersion gold has a denser crystal structure and it is not easy to be oxidized.
5. With the higher precision requirement of circuit board, the line width and spacing have reached 0.1mm or less. Gold plating is prone to shorts in gold wire. The immersion gold has only nickel gold on the pad, so it is not easy to produce a gold wire short circuit.
6. The immersion gold board has only nickel gold on the pad, so the soldering on the line is more firmly combined with the copper layer. The project does not affect the spacing when making compensation.
7. For the board with higher requirements, the flatness requirement is better. Generally, the immersion gold is used. The immersion gold generally does not appear as a black mat after prototype pcb assembly. The flatness and service life of the immersion gold board is better than that of the gold plating PCB.