Multi-layer PCB advantages: high assembly density, small size, light weight. Due to the high assembly density, the connection between components is reduced, thereby improving reliability; the number of wiring layers can be increased, thereby increasing design flexibility; it can form a circuit with a certain impedance; it can form a high-speed transmission circuit; circuit and magnetic circuit shielding layers can be set, and a metal core heat dissipation layer can be set to meet the needs of special functions such as shielding and heat dissipation; simple installation and high reliability.