1. Hot air leveling

This is the most common and inexpensive processing technology, which refers to coating the surface of the circuit board with molten tin lead solder and leveling it with heated compressed air (blowing) to form a coating layer that can resist copper oxidation and provide good solderability. Hot air leveling usually forms a copper tin metal compound at the junction between the solder and copper.

2. Chemical nickel gold deposition

Wrapping a thick layer of nickel gold alloy with good electrical function on the copper surface can protect the circuit board for a long time, unlike OSP which only serves as a rust proof barrier layer and has environmental tolerance that other surface treatment processes do not have.

3. Organic antioxidant

Also known as OSP, a layer of organic film is chemically grown on a clean bare copper surface. This film is resistant to oxidation, heat shock, and moisture, and can protect the copper surface from further rusting in normal environments. It can be easily removed by soldering aids during subsequent welding at high temperatures for welding.

4. Electroplated nickel gold

After electroplating a layer of nickel on the outer conductor of the circuit board, another layer of gold is electroplated. To avoid diffusion between gold and copper, there are currently two types of nickel gold electroplating: soft gold electroplating and hard gold electroplating. Soft gold is used for gold wire bonding during chip packaging, while hard gold is used for electrical interconnects at non solder joints, such as gold fingers.

5. Chemical precipitation of silver

Between OSP and electroless nickel plating, the process is simple and fast. Even when exposed to hot, humid, or polluted environments, it can still provide good electrical function and weldability, but the defect is that it will lose its luster. Due to the absence of nickel beneath the silver layer, it does not possess all the physical strength required for electroless nickel plating.

6. Mixed appearance processing skills

Choose two or more surface treatment methods for surface treatment. Common methods include: nickel plating OSP, nickel plating nickel plating, nickel plating hot air leveling, and nickel plating hot air leveling.

Article source: PCB manufacturerhttp://www.yonghongpcb.com/