Difference between immersion gold boards and gold plating boards

Immersion gold PCB and gold-plated PCB are processes often used in PCB manufacturing. Some customers cannot distinguish the difference between the two correctly, and some customers even think that there is no difference between the two. So what impact will these two kinds of "golden boards" have on circuit boards? Below Shenzhen PCB manufacturer SYS Technology will explain it specifically for you, and help you to clarify the concept thoroughly.

What is gold plating?

What we call the gold plating, generally refers to "electroplating gold", "electroplating nickel gold PCB", "electrolytic gold", "electric gold" and "electric nickel gold plate".

There is a distinction between soft gold and hard gold (generally hard gold is used for gold fingers). The principle is to dissolve nickel and gold (commonly known as gold salt) in chemical liquid, immerse the circuit board in the electroplating tank and turn on the current to form a nickel-gold coating on the copper foil surface of the circuit board. The electro-nickel-gold has high hardness due to the coating. The advantages are wear resistance and oxidation resistance, so it was widely used in electronic products.

So what is immersion gold? Immersion gold is a method of chemical oxidation-reduction reaction to generate a layer of plating, is a kind of chemical nickel-gold layer deposition method, can reach a thicker of 1~10 micro inch thickness gold layer.

Difference between immersion gold PCB and gold-plated PCB

1. Generally, the thickness of immersion gold is thinner than that of gold plating. Customers are more satisfied with immersion gold depending on the surface. The crystal structure formed by the two is different.

2. Since the crystal structure formed by immersion gold and gold plating is different, immersion gold is easier to weld than gold plating, and will not cause poor welding and cause customer complaints. At the same time, it is precisely because the immersion gold is softer than the gold plating, so the gold finger generally chooses gold plating, hard gold is wear-resistant.

3. The immersion gold board only has nickel and gold on the pads, and the signal transmission skin effect is on the copper layer, without affecting the signal.

4. Immersion gold has a denser crystal structure than gold plating, and it is not easy to bring oxidation.

5. As the PCB layout wiring becomes denser, the line width and spacing have reached 3-4mil. Gold plating is prone to short circuit due to gold wire. The immersion gold board only has nickel gold on the pad, so it will not bring up gold wire short circuit.

6. The immersion gold board only has nickel and gold on the pads, so the solder mask on the circuit and copper layer are more firmly combined. It will not affect the spacing during compensation.

7. For boards with relatively high requirements, the flatness requirements is also higher, immersion gold is used. Immersion gold generally does not appear black pad after assembly. The flatness and stand-by life of the immersion gold board are as good as the gold-plated board.

The above is the difference between immersion gold boards and gold plating boards. Nowadays, the price of gold on the market is expensive. In order to save costs, many manufacturers are no longer willing to produce gold plating boards.