PCB Tech - Difference Between Immersion Gold and Gold Plating

What is gold plating?
By gold plating on the whole plate, we generally refer to "electroplated gold", "electroplated nickel plated gold plate", "electrolytic gold", "electroplated gold" and "electroplated nickel gold plate". There is a distinction between soft gold and hard gold (generally hard gold is used for gold fingers).


The principle is that nickel and gold (commonly known as gold salt) are dissolved in the chemical solution, the circuit board is immersed in the electroplating tank and connected with the current to form nickel gold coating on the copper foil surface of the circuit board.


Electroplated nickel gold has been widely used in electronic products because of its high hardness, wear resistance and difficult oxidation.


What is the immersion gold?

Immersion gold is the formation of a layer of coating by chemical oxidation-reduction reaction, which is generally thicker. It is one of the chemical nickel gold deposition methods, which can achieve a thicker gold layer.

Difference between gold flash and gold plating:

1. The crystal structure formed by depositing gold is different from that of gold plating. The thickness of gold deposition is much thicker than that of gold plating. The gold deposit will be golden yellow and more yellow than that of gold plating, which makes customers more satisfied.

   
   

2. The crystal structure formed by the immersion gold is different from that of gold plating. It is easier to weld than gold plating. It will not cause poor welding and cause customer complaints. The stress of gold plate is easier to control, which is more conducive to the processing of bonding products. At the same time, because the sinking gold is softer than the gold plating, the gold plated plate is not wearable.

   
   

3. In the skin effect, the signal transmission is in the copper layer, which will not affect the signal.

   
   

4. Compared with gold plating, the crystal structure of deposited gold is denser and it is not easy to form oxidation.

   
   

5. As the wiring becomes more and more dense, the line width and spacing have reached 3-4mil. Gold plating is easy to produce gold wire short circuit. There is only nickel and gold on the pad, so there will be no gold wire short circuit.

   
   

6. Only nickel and gold are found on the pad of the sinking gold plate, so the bonding between the solder mask and the copper layer on the circuit is more firm. The project will not affect the spacing when making compensation.

   
   

7. Generally used for relatively high requirements of the board, flatness is good, generally used to sink gold, sinking gold generally will not appear after the assembly of black pad phenomenon. The flatness and service life of the gold plate are as good as those of the gold plate.