What Are The Common Surface Treatment Processes For Circuit Boards?

The circuit board plays an important role in many machines, so the quality requirements of the circuit board are also very high. So what are the surface treatment processes commonly used in the surface treatment of the circuit board?

First. Full plate nickel-plated gold

The plated nickel-gold plate is a layer of nickel and then a layer of gold on the surface conductor of the PCB. Nickel plating is mainly to prevent the diffusion between gold and copper. There are two types of electroplated nickel gold: soft gold and hard gold. Soft gold is mainly used to wire gold when chip packaging; hard gold is mainly used to electrically interconnect non-soldering places.

Second, hard gold plating

In order to improve the wear resistance of the product, the number of mating cycles is increased and the hard gold is plated.

Third. Shen Jin

Shenjin is a thick layer of nickel-gold alloy with good electrical properties on the copper surface, which can protect the PCB for a long time. In addition, it also has environmental tolerance that other surface treatment processes do not have. In addition, immersion gold can also prevent the dissolution of copper, which will benefit lead-free assembly.

Fourth: chemical nickel palladium

Compared with immersion gold, electroless nickel-palladium has a layer of palladium between nickel and gold. Palladium can prevent the corrosion phenomenon caused by the substitution reaction, and is fully prepared for immersion gold. Gold tightly covers the palladium, providing a good contact surface.

Fifth. Shen Yin

The immersion silver process is between organic coating and electroless nickel / immersion gold. The process is relatively simple and fast; even if exposed to heat, humidity and pollution, silver can still maintain good solderability, but it will lose its luster. . Immersion silver does not have the good physical strength of electroless nickel / immersion gold because there is no nickel under the silver layer.