PCB News - What are the benefits of using precious metals such as gold and silver on printed circuit boards?

What are the benefits of using precious metals such as gold and silver on printed circuit boards?

Printed circuit boards are referred to as PCBs. They have been developed for tens of hundreds of years. The common PCB colors on the market are red, yellow, green, blue, black, etc. However, due to problems such as manufacturing processes, many lines are of high quality. The inspection process still has to rely on workers' visual observation and recognition. Therefore, when working in an environment where strong light is continuously illuminated, relatively speaking, green does not hurt the eyes. Therefore, it is common for most manufacturers to use green PCBs. The principle of blue and black is that they are doped with elements such as cobalt and carbon, respectively, and have certain electrical conductivity. Short circuit problems are likely to occur when energized, and green PCBs are relatively environmentally friendly and are used in high-temperature environments. At times, toxic gases are generally not released.

Before the advent of printed circuit boards, the interconnection between electronic components relied on the direct connection of wires to form a complete circuit. Printed circuit boards have developed from single-layer to double-sided boards, multilayer boards and flexible boards, and continue to develop in the direction of high precision, high density and high reliability. Secondly, due to the need to solder components on the PCB surface, a part of the copper layer is required to be exposed.

The exposed surface is used for soldering. These exposed copper layers are called pads. The pads are generally rectangular or round with a small area. If the copper on the pad is oxidized, it will not only be difficult to solder, but also the resistivity will greatly increase, which will seriously affect the performance of the product. Therefore, engineers have come up with various methods to protect the pads. For example, it is plated with inert metal gold, or the surface is covered with a layer of silver through a chemical process, or a special chemical film is used to cover the copper layer to prevent contact between the pad and the air.

Therefore, the copper layer of the exposed pad on the PCB is directly exposed. This part needs to be protected to prevent it from being oxidized. From this perspective, whether it is gold or silver, the purpose of the process itself is to prevent oxidation and protect welding. To ensure the yield in the next welding process. It is said that there are still many precious metals on the PCB. In daily life, each smart phone used by each of us contains 0.05g gold, 0.3g silver, and 13.6g copper. The gold content of each notebook computer is more than ten times that of mobile phones. In fact, precious metal plating materials It is not only a key material for the manufacture of printed circuit boards, but also an important material for achieving excellent performance of the chip. For example, the pins and lead frames used in the chip connection are almost all silver-plated, while the electrode materials of the chip, the integrated circuit board wire coating, LED light-emitting chips also need to be electroplated with precious metal electroplating materials such as gold, platinum, and silver. It can be said that the development of my country's integrated circuit industry is also inseparable from the support of precious metal electroplating materials.

However, the use of different metals will impose requirements on the storage time and storage conditions of the PCB used in the production plant. Therefore, many domestic PCB manufacturers generally use vacuum plastic packaging machines to package the PCB before the PCB production is completed and delivered to the customer to ensure that the PCB is not oxidized to a large extent. And before the components are soldered on the machine, the board card manufacturer must check the oxidation degree of the PCB once to eliminate the oxidized PCB to ensure the good product rate. When consumers get the boards and cards, they have passed various tests. Even if they are used for a long time, the oxidation will almost only occur in the plug-in connection parts, and it will have no effect on the pads and the components that have been soldered. .

The above is the reason why the editor talks about why precious metals appear in printed circuit boards. I hope to help everyone. Our PCB factory always insists on using superb technical force, sophisticated production equipment, and perfect testing methods. The industry-standard product quality and warm and thoughtful service have won praise and welcome from merchants and users all over the world.