PCB Technical - PCB factory sinking gold and gold plating difference

PCB factory circuit board surface treatment process includes: anti-oxidation, tin spray, lead-free tin spray, immersion gold, immersion tin, immersion silver, hard gold plating, full board gold plating, gold fingers, nickel palladium gold OSP, etc.

Immersion gold and gold plating are processes often used in PCB circuit boards. Many engineers can't distinguish the difference between the two correctly, so today I will summarize the difference between the two.

What is gilding?

The gold plating of the whole board generally refers to "electroplating gold", "electroplating nickel gold plate", "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 water, immerse the circuit board in the electroplating tank and turn on the current to form a nickel-gold plating layer on the copper foil surface of the circuit board.

Electro-nickel gold is widely used in electronic products because of its high hardness, abrasion resistance and resistance to oxidation.

What is Immersion Gold?

Immersion gold is a method of chemical oxidation-reduction reaction to generate a layer of plating, generally thicker, is a kind of chemical nickel-gold layer deposition method, can reach a thicker gold layer.

The difference between Immersion Gold Plate and Gold Plated Plate

1. Generally, the thickness of immersion gold is much thicker than that of gold plating. Immersion gold will be golden yellow and more yellow than gilding. 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 plate generally chooses gold plating, hard gold is wear-resistant.

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

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

5. As the wiring becomes denser, the line width and spacing have reached 3-4MIL. Gold plating is prone to short circuit of gold wire. Immersion gold board only has nickel gold on the pad, so it will not produce 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 the copper layer are more firmly combined. The project will not affect the spacing during compensation.

7. Generally used for relatively high-demand boards, the flatness is better, and generally the use of immersion gold, immersion gold generally does not appear the phenomenon of black pads after assembly. The flatness and stand-by life of the immersion gold board are as good as the gold-plated board.

8. Now the price of gold on the market is expensive. In order to save costs, many manufacturers are no longer willing to produce gold-plated plates, and only make immersion gold plates with nickel-gold on the pads. The price is indeed much cheaper.

1. Immersion gold board and chemical gold board are the same process product, electric gold board and flash gold board are also the same process product, in fact, it is just a different name for different people in the PCB industry. Immersion gold board and electric gold board are more common in The title of the mainland counterparts, while the Huajin board and the flash gold board are more commonly referred to by the Taiwan counterparts.

2. Immersion gold plate/chemical gold plate is generally called chemical nickel gold plate or chemical nickel immersion gold plate. The growth of nickel/gold layer is plated by chemical deposition.

3. The gold electroplated gold plate/flash gold plate is generally called electroplated nickel gold plate or flash gold plate. The growth of the nickel/gold layer is plated by DC electroplating.