How are the different layers in a multilayer PCB electrically connected?
PCB (Printed Circuit Board), the Chinese name is printed circuit board, also known as printed circuit board. It is an important electronic component, a support for electronic components, and a carrier of Electronic Components and Electronic connectors. Because it is made by electronic printing, it is called a "printed" circuit board.
As electronic devices become more and more complex, more and more parts are needed, and the circuits and parts on the PCB are getting denser.
In the double-layer PCB, you can see the bridges connecting the circuits, which we call "vias". A via is a small hole filled or coated with metal on the PCB. It can be connected to the wires on both sides of the double-layer PCB. In a multi-layer PCB, the wires of each layer are generally connected through blind holes (blind via hole PCB can be seen from the surface) or buried holes (buried PCB can not be seen from the surface)
The small circuit material that can be seen on the surface of the PCB is copper foil. The copper foil was originally covered on the entire PCB, but part of it was etched away during the manufacturing process, and the remaining part became a small mesh circuit. .
These lines are called copper film traces, or wires for short. (Or wiring), and used to provide the circuit connection of the Electronic Components on the PCB.
