As PCB factory china knows that，a PCB substrate is the material that holds the traces and components that make up the foundation of a printed circuit board. Selecting the right substrate material is crucial for the outcome and success of a high-quality PCB project.

PCB substrates are created in a way that has often been compared to a sandwich. Generally, the layers are indicated as follows:

At the center is the core, a rigid base material that serves as the printed circuit board’s primary insulating material which is usually covered in copper foil as an internal ground plane.

Coating the core is prepreg, a dielectric material binding agent that covers the core.

An outer layer of foil is attached to the surface, forming the surface area which component parts will be attached and traces will be etched.

Finally, the solder mask is applied on the surface, which is used primarily to protect the copper traced from oxidation, prevent solder bridges, and assist in visual inspections of the board.

Silkscreen is added to indicate what parts lie where on a board, and while they are considered a layer of their own, it provides no material benefit.

When we are referring to the PCB substrate, we are generally referring to the prepreg and core material. Substrates offer a variety of options that are designed to suit the purpose of the end-user.