What is The Meaning of Each Layer in PCB?

Each layer of a PCB has its own specific meaning and function, the following are some of the main layers and their meanings:

Top Layer: Also known as the parts layer, mainly used to place components, for double-layer boards and multilayer boards can be used to arrange wires or copper cladding.

Bottom Layer: Also known as the soldering layer, mainly used for wiring and soldering, for double-layer boards and multilayer boards can be used to place components.

Middle Signal Layers: Up to 30 layers, used in multilayer boards for the layout of the signal lines, which do not include the power lines and ground lines.

Internal Planes: Often referred to as internal planes, they are only found in multilayer boards. Same as the signal layer, the internal power layer and the internal power layer, the internal power layer and the signal layer can be connected to each other through holes, blind holes and buried holes.

Soldermask Layer: This layer makes the PCB look green.

Solder Paste Protection Layer: It is similar to the role of the Solder Resist Layer, the difference is that in the machine soldering corresponds to the surface of the components of the pads pasted.

Silkscreen Layer: The white characters are the silkscreen layer.

Mechanical Layer: Generally used to place information about the plate and assembly methods.

Keep-Out Layer: Defined on the copper side of the cloth electrical characteristics of the boundary. After defining the Keep-Out Layer, the wires with electrical characteristics cannot go beyond the boundary of the Keep-Out Layer in the subsequent wiring process.

Multi-layer: Refers to all layers of the PCB board, including the top layer, bottom layer and intermediate signal layer.

Drill Guide Layer: The layer used to guide the drilling operation.

Drill Location Layer: The layer used to identify the location of the drill holes.

Screw Hole Layer: Layer used to guide the installation of screws.

Through-hole Layer: Layer used to guide through-hole installation.

Other Special Layers: Set up according to the specific needs of the special layer, such as metallized holes, blind holes, etc...

These layers are set up to meet the specific needs of the PCB manufacturing and assembly process, which helps to improve the performance and reliability of the PCB. In the actual PCB design and manufacturing process, depending on the specific needs and process requirements, different layers and settings may be used to achieve the best results.