What is the basic structure of PCB design?

The basic structure of PCB design mainly includes the following three core layers, 

which together constitute the complete functional system of the circuit board:

This is the core part for realizing circuit functionality, usually made of copper foil. The copper foil is processed through etching. 

Conductive layers can be divided into signal layers (such as top layer and bottom layer) and reference planes (such as power and ground layers). 

Signal layers are used to transmit electrical signals, while reference planes (power and ground layers) provide low-impedance return paths for signals. 

In multilayer boards, signal layers and reference planes need to be closely paired to reduce interference.

The PCB laminate design is achieved by alternating stacking of cores and prepreg (PP) sheets. The core is a rigid double-sided copper-clad substrate that can serve as a signal or power layer. 

Prepreg is used to bond the layers together and is non-conductive. The laminate must be symmetrically designed (such as for an even number of layers) to prevent warping. For example,

 a 6-layer board structure might be: signal layer - ground layer - signal layer - power layer - ground layer - signal layer. Multilayer boards achieve inter-layer connections through vias, blind vias, or buried vias.

By reasonably designing the laminate and layer distribution, signal integrity, power stability, and manufacturing costs can be optimized.