Why are PCB multilayer boards even-numbered layers?

PCB multilayer board refers to a circuit board formed by stacking multiple copper layers and insulating layers on a substrate with two or more layers. In the design of PCB multilayer boards, there are usually even layers instead of odd layers. This is because even-numbered PCB multilayer boards have better electromagnetic compatibility and signal integrity, and are also easier to design and manufacture. This article will introduce in detail the definition of PCB multilayer boards, the advantages of even-numbered layers, the defects of odd-numbered layers, and the manufacture of PCB multilayer boards.

First of all, PCB multilayer board refers to a circuit board formed by stacking multiple copper layers and insulating layers on two or more substrates. The design of the PCB multilayer board can increase the density of the circuit board, reduce the volume of the circuit board, and also improve the performance and reliability of the circuit board. In the design of PCB multilayer boards, there are usually even layers instead of odd layers.

Secondly, even-numbered PCB multilayer boards have better electromagnetic compatibility and signal integrity. In even-numbered PCB multilayer boards, the copper layers of each layer can be designed in a symmetrical manner, thereby reducing electromagnetic radiation and electromagnetic interference. At the same time, in the even-numbered multilayer PCB, the signal layer and the power layer can be designed in a symmetrical manner, thereby reducing signal transmission loss and noise. Therefore, even-numbered PCB multilayer boards have better electromagnetic compatibility and signal integrity.

However, there are some defects in odd-numbered PCB multilayer boards. In odd-numbered PCB multilayer boards, electromagnetic radiation and electromagnetic interference are prone to occur due to the lack of symmetry. At the same time, in odd-numbered PCB multilayer boards, the distance between the signal layer and the power layer is inconsistent, which is prone to signal transmission loss and noise. Therefore, PCB multilayer boards with odd layers are not as good as electromagnetic compatibility and signal integrity as even layer PCB multilayer boards.

Finally, the manufacture of PCB multilayer boards needs to take into account several factors. In the manufacture of PCB multilayer boards, factors such as the selection of the number of layers, the selection of the stacking method, the thickness of the copper layer and the insulating layer, and the connection method between layers need to be considered. At the same time, the manufacture of PCB multilayer boards also needs to take into account the requirements of the manufacturing process, such as interlayer lamination, drilling, copper plating, patterned etching and other processes.

In short, PCB multilayer boards are usually even-numbered layers, because even-numbered PCB multilayer boards have better electromagnetic compatibility and signal integrity, and are also easier to design and manufacture. In the manufacture of PCB multilayer boards, multiple factors need to be considered to ensure the performance and reliability of PCB multilayer boards.