Next, we will delve into the differences between gold plating and immersion plating in the production of PCBA circuit boards.
1、 Gold plating process
The gold plating process mainly uses electroplating to uniformly attach gold particles to the PCB board. Due to its strong adhesion, it is often referred to as “hard gold”. For example, the gold fingers on memory modules are usually processed using this technique due to their high hardness and good wear resistance.
In the gold plating process, a layer of nickel is usually plated first, followed by a layer of gold. This copper nickel gold metal layer structure not only enhances the adhesion of the gold layer, but also plays a certain role in electromagnetic shielding due to the magnetic properties of nickel.
However, a potential issue with the gold plating process is that it is performed before solder mask, and sometimes there may be situations where the green oil is not cleaned thoroughly, which may affect the subsequent soldering and tinning processes.
2、 Sinking gold process
In contrast, the gold deposition process generates a weak adhesion gold coating on the solder pads of the PCB board through chemical oxidation-reduction reactions, commonly known as “soft gold”.
The gold deposition process is carried out after solder mask, so it is less susceptible to the influence of unclean green oil cleaning, making it easier to achieve good soldering and tinning effects. In addition, the gold deposition is directly carried out on the copper skin, and the metal layer structure is copper gold without a nickel layer, so it does not have a magnetic shielding effect.
From the perspective of crystal structure, deposited gold is easier to weld than gold because its crystal structure is denser and less prone to oxidation, which helps reduce the risk of poor welding. In addition, circuit boards that have undergone gold plating treatment usually have better flatness, which is an important advantage for boards with higher requirements.
In summary, both gold plating and immersion gold have their own advantages in the production of PCBA circuit boards. The gold plating process has advantages in situations where wear resistance and electromagnetic shielding are required due to its high adhesion and electromagnetic shielding properties; The immersion gold process is favored in demanding surface mount processing due to its excellent welding performance, flatness, and resistance to oxidation. When choosing which process to use, it should be comprehensively considered based on specific product requirements and application scenarios.