Why Multilayer PCB Is Used So Widely

This Gold Phoenix PCB Knowledge Center article explains why multilayer PCBs are widely used, covering their construction, advantages such as high assembly density and impedance control, as well as disadvantages including cost and longer production cycles.

The multilayer PCB is mainly used in professional electronic equipment, such as computers and military equipment, especially in the case of the overload of weight and volume. The multilayer PCB is also very useful in high-speed circuits. The multilayer PCB can provide more space for the conductor pattern and power.

The multilayer PCB is made up by two or more PCBs which are stacked together with reliable predefined mutual connection between them. There are at least three conductive layers in one multilayer PCB, with two layers outside and one layer synthetized in the insulation board. Due to the complex manufacturing process and lower production, the cost of multilayer PCB is relatively higher.

The emergence of multilayer PCB results from requirements of the development of electronic technology, such as high speed, multi-function, high-capacity, small size. On one hand, as the electronic devices are becoming smaller and lighter, single-sided PCB and double-sided printed PCB cannot match increasing assembly density due to the limit of available space. On the other hand, there are many problems in the PCB layout such as noise, stray capacitance, crosstalk and so on. Therefore, the design of PCB must be committed to minimizing the length of the signal line and avoiding the parallel routes. Obviously, single-sided PCB or double-sided PCB cannot meet the requirement because of the limited intersections that can be achieved. Under the demand of large number of interconnections and crosses, the PCB can achieve a satisfactory performance unless the PCB is expanded to more than two layers. Then the multilayer PCB comes onto the market.

At present, multilayer PCB has been widely used in various electronic devices and it has become an important part among the electronic components owing to its numerous advantages, such as high assembly density, small size, good quality; reliability, flexibility, the constitution of a circuit with impedance; the formation of high-speed transmission circuit, the setup of shielding layer for electronic circuit and magnetic circuit, simple installation and so on. But there are two sides for everything. For multilayer PCB, some disadvantages still remain, such as high cost, long production cycle, high requirement of testing method.

With the development of technology, multilayer PCB will become more and more perfect and will be applied in more and more fields.