In the circuit board production process, the immersion gold and gold plating processes are very common processes. Because these two processes solve the problem of difficult to flatten the solder pads in the tin spray industry, with the strictness of the function and size of electronic products in society Requirements, resulting in PCB boards becoming more and more sophisticated as mother boards of electronic components. Electronic products, especially IC and BGA, have extremely high requirements for the flatness of circuit board pads, so the immersion gold and gold plating processes are in a sense Can replace tin spraying process. The lead-tin alloy soldering cycle is much shorter than the time of immersion gold or gold-plated board.
Immersion gold plate refers to the formation of a layer of plating on the surface of copper skin through chemical oxidation-reduction reaction, which is relatively thick and is a kind of chemical nickel-gold layer deposition.Gold-plated circuit board generally refers to dissolving nickel and gold in chemical liquid, immersing the circuit board in the electroplating cylinder and passing current to generate nickel-gold coating on the copper foil of the circuit board. The electrical gold has high hardness and resistance Abrasion, not easy to oxidize until widely used.
Immersion gold circuit boards are also different from gold-plated circuit boards. Immersion gold is different from gold plating in a certain crystal structure, which makes it seem that immersion gold is much more than gold plating, and customers look more satisfied. Due to the difference in crystal structure, the immersion gold conductor is easier to weld than gold plating, and it is easier to weld, and the defect rate is much lower than that of gold plating.
The nickel-gold structure is on the gold plate, so the skin effect is much better than gold plating. The crystal structure of Shen Jin is denser, so it will not be easily oxidized. Immersion gold only has nickel gold on the pad, so the combination of the solder mask on the circuit and the copper layer is stronger. Because the crystal structure formed by immersion gold and gold plating is different, the stress of its immersion gold plate is easier to control, and for the products with bonding, it is more conducive to bonding processing. At the same time, it is precisely because the immersion gold is softer than the gold plating, so the immersion gold plate does not wear gold fingers. The flatness and service life of the immersion gold plate are as good as the gold-plated plate.
In terms of use, due to environmental protection and other reasons, gold plating has high hardness and wear resistance due to the crystal structure. It is generally used for gold finger and other frequently assembled process surfaces. Immersion gold is soft and easy to solder, and is usually used on the pad. Broadly speaking, the immersion gold process is more widely used and less restrictive than the gold plating process.