Have you noticed that there have been more and more motherboards with black PCBs in recent years? Some people say that this is one of the symbols of high-end motherboards, which was not a problem in the early days, after all, most motherboards used green and yellow PCBs. Later, manufacturers such as Asus began to introduce black PCBs as standard equipment for high-end motherboards in order to differentiate the performance and grade of motherboards with the same chipset.

Later on, you will know that other motherboard manufacturers have also followed suit and extended it to graphics cards, memory, and even solid-state drives, with a strong sense of 'all PCBs can be black'. So is black PCB really synonymous with high-end products?

This requires studying how black PCBs come from. In fact, PCBs come in many colors, including green, yellow, and now black, as well as various colors such as red, white, orange, and blue.

In fact, different colors of PCBs have the same manufacturing materials and processes, including the location of the copper layer. After the etching process, the final wiring is left on the PCB. For example, in the newly etched PCB shown in the figure below, the copper wiring is the original copper color, while the PCB substrate is slightly yellowish.

To prevent the copper layer from being oxidized and leaving too much solder on the circuit when soldering components, a glass epoxy tree should be used to cover the surface of the PCB as a solder mask. Early glass epoxy resin was usually green, and the copper layer on the PCB was very thin, so the prepared PCB showed a bright green color. Then, the solder pad of the component was removed from the solder mask (window opening) to proceed with the component welding process.

Different industries have different requirements for PCB color, so now glass epoxy resin has introduced some other colors, which makes the manufactured PCBs present different colors. That is to say, different colored PCBs not only have similar manufacturing processes and methods, but black PCBs are made of special colored epoxy resin.

To a certain extent, it will increase the manufacturing cost, but there are also some side effects, such as the difficulty of checking the wiring of PCBs with too dark colors, which will increase the difficulty of maintenance.

Green PCBs are the most common in the industry, as they are less prone to eye fatigue during long-term inspection operations on the testing line. Moreover, PCBs have better recognition performance with optical positioning instruments for SMT welding of components. Of course, the cost of using green glass epoxy resin to manufacture motherboards is also slightly lower.

So, does this mean that green PCB is synonymous with low-end? In fact, in many fields, green PCBs are more favored, such as server motherboards, which are mostly green PCBs, and even in the military industry.

Today, the popularity of black PCB motherboards is actually led by brands such as Asus. Their electrical performance is the same, but the manufacturer has defined their purpose and grade.

Nowadays, even second and third tier motherboard brands are heavily using black PCBs, which has reached a rampant level. Green and yellow PCBs have disappeared. So, do you still think that black motherboards are necessarily high-end products?