Date: 2026-07-04 hits: 101
What are the benefits of using precious metals like gold and silver on PCBs?
First, let's clarify the colors, then discuss the precious metals on PCBs. Some manufacturers, when promoting their products, specifically mention adopting special processes such as gold plating or silver plating. So, what is the actual use of such processes?
PCB surfaces require soldering components, which means a portion of the copper layer must be exposed for soldering. These exposed copper areas are called pads, which are typically small rectangles or circles. We know that copper used in PCBs is highly prone to oxidation. Therefore, after applying solder mask, the only copper exposed to the air is on the pads.
If the copper on the pads oxidizes, it not only becomes difficult to solder but also significantly increases resistivity, severely affecting the final product's performance. Hence, engineers have devised various methods to protect the pads. For example, coating them with the inert metal gold, covering the surface with a layer of silver through chemical processes, or using a special chemical film to cover the copper layer and prevent contact with air.
The exposed pads on PCBs have copper directly exposed. This part needs protection to prevent oxidation. From this perspective, whether it's gold or silver, the purpose of these processes is to prevent oxidation and protect the pads, ensuring good yield during subsequent soldering processes.
However, using different metals imposes requirements on the storage time and conditions of PCBs for production factories. Therefore, PCB manufacturers generally package PCBs in vacuum-sealed machines after production and before delivery to customers, maximizing the prevention of oxidation damage.
Before the final component mounting and soldering, the board production manufacturer will test the oxidation level of the PCB again, removing oxidized PCBs to ensure yield. The final PCBs received by consumers have undergone various tests. Even after long-term use, oxidation mainly occurs at the plug-and-socket connection points and has little impact on the pads and already soldered components.
Since silver and gold have lower resistivity, would using these special metals reduce heat generation when PCBs are in use?
We know that the primary factor affecting heat generation is resistance. Resistance is related to the material of the conductor, its cross-sectional area, and length. The thickness of the metal material on the pad surface is even less than 0.01 millimeters. For pads treated with OST (Organic Solderability Preservative), there is no additional thickness. The resistance exhibited by such a tiny thickness is practically zero or negligible, so it certainly does not affect heat generation.
