There Are Several Methods For Surface Treatment Of PCB Multilayer Board?

May. 28, 2020

1. Hot air leveling the molten tin-lead solder coated on the PCB surface and heating compressed air leveling (air blowing leveling) process. Make it form a copper oxidation resistant coating, which can provide good solderability.


2. Organic anti-oxidation grows a layer of organic coating on the clean bare copper surface by chemical methods. This PCB multilayer board film has anti-oxidation, thermal shock resistance, and moisture resistance to protect the copper surface from rusting (oxidation or vulcanization, etc.) under normal environments. At the same time, at the subsequent soldering temperature, the soldering flux is easily removed quickly.


3. Nickel-gold chemistry is coated on the copper surface with thick, good nickel-gold alloy electrical properties, which can protect the PCB multilayer board. For a long time, unlike OSP, it is only used as an anti-rust layer. It can be used for long-term use of PCB and obtain good power. In addition, it also has environmental resistance that other surface treatment processes do not have.


4. Electroless silver plating is deposited between OSP and electroless nickel / gold plating. The PCB multilayer board process is simple and fast. Exposure to hot, humid, and polluted environments still provides good electrical properties and good solderability, but loses its luster. Since there is no nickel under the silver layer, the precipitated silver does not have all the good physical strength of electroless nickel plating / immersion gold.


5. Nickel and gold are plated on the surface conductor of the PCB multilayer board, first a layer of nickel and then a layer of gold. The nickel plating is mainly to prevent the diffusion between gold and copper. There are two types of nickel-plated gold: soft gold (pure gold, which means it does not look bright) and hard gold (smooth, hard, wear-resistant, cobalt and other elements, the surface looks brighter). Soft gold is mainly used for chip packaging gold wire; hard gold is mainly used for non-solder electrical interconnection.


6. PCB mixed surface treatment technology choose two or more surface treatment methods for surface treatment, common forms are: nickel-gold anti-oxidation, nickel-plated gold precipitation nickel-gold, electroplated nickel-gold hot air leveling, common forms are: nickel Gold anti-oxidation, nickel-plated gold precipitation nickel gold, electroplated nickel-gold hot air leveling, heavy nickel and gold hot air leveling Although the changes in the surface treatment process of PCB multilayer boards are not significant and seem to be somewhat far-fetched, it should be noted that long-term slow changes will lead to huge changes. As the demand for environmental protection continues to increase, the surface treatment process of PCBs is bound to change dramatically in the future.


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