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PCB production, immersion gold process and tin spray process description

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High frequency pcb manufacturing surface treatment technology: immersion gold process and spray tin process

High frequency PCB manufacturing, immersion gold process (Immersion Gold) and spray tin process (Hot Air Solder Leveling, HASL) are two commonly used surface treatment technology, they each have different advantages and disadvantages and uses.

Immersion Gold Process



Gold has good conductivity, suitable for high frequency signal transmission. 

Corrosion Resistance:

The gold layer is not easy to oxidise and has good corrosion resistance. 


The gold layer formed by the immersion gold process has a beautiful colour and enhances the appearance of the product.

Welding Performance: 

The gold layer has good affinity with solder, which is conducive to welding.


The gold layer has a dense crystal structure, which is not easy to produce oxidation and enhances the durability and reliability of the PCB.

Stress Control:

Immersed gold boards have more precise control of stress during the manufacturing process.



The cost of immersion gold process is relatively high.

Golden Wire Short Circuit: 

Due to the ductility of gold, golden wire may be generated, causing the risk of micro-short circuit. 


PCB for high frequency and high speed signal transmission.

Electronic equipment requiring long-term stable operation.

For occasions with high requirements for soldering performance and corrosion resistance.

Spray tin process (Hot Air Solder Leveling, HASL)




Spray tin process costs less, suitable for mass production. 

Soldering Performance: 

Thicker tin layer provides good soldering performance. Tin Spraying.jpeg

Surface Flattening: 

Smoother surface of tin layer by hot air flattening.

Widely Used: 

Suitable for many types of PCBs, especially wide lines and large pad boards.


Corrosion Resistance: 

The tin layer is easier to oxidise, the corrosion resistance is not as good as the gold layer.


The coating layer is not flat enough, which may affect the quality of SMT mounting.

Standby Life: 

the standby life of the tin spray board is shorter, not suitable for long-term storage. 

Environmental Impact: 

The tin spraying process may produce odour, which has a high impact on the environment.


PCBs for general signal transmission.

Cost-sensitive products.

For applications that require high solderability but not high corrosion resistance.

Immersion gold process and spray tin process have their own advantages and limitations. Immersion gold process due to its high conductivity and corrosion resistance, more suitable for high-frequency and high-speed signal transmission PCB, while the tin spray process due to its cost-effective and good soldering performance, suitable for general signal transmission and cost-sensitive products. Manufacturers need to choose the right surface treatment technology based on the product's performance requirements, cost budget and application environment.

Immersion gold is particularly suitable for high-density and ultra-small form-factor processes because it solves the problem of vertical tin spraying, which has difficulty in blowing fine pads flat, and the waiting life of immersion gold boards is many times longer than that of Pb-Tin alloy boards. While the spray tin process is suitable for wide line and large pad boards due to its cost-effectiveness and soldering performance, it is usually not used for HDI boards. In addition, the immersion gold process can improve the quality of signal transmission and reduce signal loss and interference in the production of high-frequency boards, which is suitable for high-frequency, high-speed and high-precision circuits.

Xinchenger Electric is a professional 2-36 layer high frequency PCB circuit board manufacturer, can expedite the production of high frequency PCB boards, mixed pressure high frequency boards, special circuit boards, microwave RF boards, microwave antenna boards and other products, the company is always on hand: Rogers, Taconic, F4B, TP-2, FR-4 and other high frequency boards.

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