PCB Technical - Process and function of chemical nickel palladium gold

Chemical nickel palladium gold is an important surface treatment process in the printed circuit board industry, which is widely used in the production process of hard circuit boards (PCB), flexible circuit boards (FPC), rigid scrambled boards and metal substrates. It is also an important development trend of the surface treatment of the printed circuit board industry in the future.

1. Chemical nickel palladium gold
The chemical nickel palladium gold is to deposit a layer of nickel, palladium and gold on the surface of the copper layer of the printed circuit by a chemical method, which is a non-selective surface processing technology. The main process flow is oil removal-micro-etching-pre-dipping-activation-nickel deposition-palladium deposition-gold deposition-drying. There will be multi-stage water washing between each link for treatment. The mechanism of chemical nickel-palladium-gold reaction mainly includes oxidation-reduction reaction and displacement reaction. Among them, reduction reaction is easier to deal with thick palladium and thick gold products.

At present, the general factory chemical nickel, palladium and gold production specifications are: nickel 2-5um, palladium 0.05-0.15um, and gold 0.05-0.15um. Of course, due to the difference of plant equipment and reaction mechanism, the uniformity of the chemical reaction And the processing ability to deal with thick palladium and thick nickel is also different.

2. Chemical nickel palladium gold VS electroplating nickel gold

1. It is also an important surface treatment process in the field of printed circuit boards;
2. The main application area is wire bonding technology, which can cope with high-end electronic circuit products to a certain extent.
3. Although the reaction rate of chemical nickel-palladium-gold is slow, because it does not require lead wires and electroplating wires to connect, the number of products produced at the same time in a tank of the same volume is much larger than that of electroplated nickel-gold, so the overall production capacity is very large. Advantage.
4. Development trend
As mentioned earlier, the main advantage of chemical nickel palladium gold is to deal with the surface treatment of high-end products and fine circuits. However, the development of electronic technology and its accompanying demand are also growing rapidly. At present, the common chemical nickel palladium gold process is in In response to the production of high-precision circuits, it will gradually become inadequate. Therefore, in order to cope with higher demand, the current main development directions are thin nickel-palladium-gold technology and chemical palladium-gold technology.