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PCB Tech

PCB Tech

PCB Tech

PCB Tech

What is the role of the immersion gold process on the surface of the PCB printed circuit?
2021-09-30
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Author:Downs

     There is a very common process used in the surface treatment of circuit boards, called Immersion Gold. The purpose of the gold immersion process is to deposit a nickel-gold coating with stable color, good brightness, flat coating, and good solderability on the surface of the PCB printed circuit.

     To put it simply, immersion gold is a method of chemical deposition to produce a layer of metal coating on the surface of the circuit board through a chemical oxidation-reduction reaction.

1. The role of immersion gold technology

    The copper on the circuit board is mainly red copper, and the copper solder joints are easily oxidized in the air, which will cause electrical conductivity, that is, poor tin eating or poor contact, which reduces the performance of the circuit board, so the copper solder joints need to be surface treated , Immersion gold is to plate gold on it. Gold can effectively block the copper metal and air to prevent oxidation. Therefore, Immersion gold is a surface anti-oxidation treatment. It is a chemical reaction to cover the surface of copper with a layer of gold, also called Chemical gold.

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2. Immersion gold can improve the surface treatment of PCB board

   The advantage of the immersion gold process is that the color deposited on the surface is very stable when the circuit is printed, the brightness is very good, the coating is very smooth, and the solderability is very good. Immersion gold generally has a thickness of 1-3 Uinch, so the thickness of gold produced by the surface treatment method of Immersion Gold is generally thicker, so the surface treatment method of Immersion Gold is generally used in key boards, gold finger boards and other circuit boards. Because gold has strong conductivity, good oxidation resistance and long service life.

Third, the benefits of using immersion gold circuit boards

 1. Immersion gold plates are bright in color, good in color and good-looking, which enhances the attractiveness of customers.

2. The crystal structure formed by immersion gold is easier to weld than other surface treatments, can have better performance and ensure quality.

3. Because the immersion gold board only has nickel and gold on the pad, it will not affect the signal, because the signal transmission in the skin effect is on the copper layer.

4. The metal properties of gold are relatively stable, the crystal structure is denser, and oxidation reaction is not easy to occur.

5. Because the immersion gold board only has nickel and gold on the pads, the solder mask on the circuit and the copper layer are more firmly combined, and it is not easy to cause micro short circuits.

6. The project will not affect the distance when making compensation, which is convenient for work.

7. The stress of the immersion gold plate is easier to control, and the experience in use is better.

Fourth, the difference between Immersion Gold and Gold Finger

  Golden fingers are more straightforward. They are brass contacts, or conductors. To be more specific, because gold is highly resistant to oxidation and conductive, the parts connected to the memory socket on the memory stick are plated with gold, and then all signals are transmitted through the gold fingers. Because the gold finger is composed of numerous yellow conductive contacts, the surface is gold-plated and the conductive contacts are arranged like fingers, hence the name. In layman's terms, the gold finger is the connecting part between the memory stick and the memory slot, and all signals are transmitted through the gold finger. The gold finger is composed of many golden conductive contacts. The gold finger is actually coated with a layer of gold on the copper clad board through a special process.

   Therefore, the simple distinction is that gold is a surface treatment process forcircuit boards, and gold fingers are components that have signal connections and conduction on the circuit board. In actual market conditions, gold fingers may not be real gold on the surface. Because of the high price of gold, most memories are now replaced by tin plating. Tin materials have been popular since the 1990s. At present, the "golden fingers" of motherboards, memory and graphics cards are almost all made of tin. Materials, only part of the contact points of high-performance servers/workstations will continue to be gold-plated, which is naturally expensive.