The Introduction of PCB Each Layer

The Introduction of PCB Each Layer


A. Signal Layers: The signal layers include Top Layer, Bottom Layer, Mid Layer1-30. These layers are all electrical connection layers, that is to say, they are the actual copper layers. The middle layer refers to a middle board layer for wiring.


B. Internal Plane Layer: Internal Plane 1-16. This kinds of layers are only used for multi-layers boards. These layers are usually connected with ground and power to be power plane layer and ground plane layer, and also have an electrical connection function. They are also the actual copper layer. However, the layer is not often wiring, but made by the whole film of copper.  Double board, 4layers board, and 6layers board generally refer to the number of internal plane layer and the signal layer.


C. Silkscreen Overlay: It includes top overlay and bottom overlay. Slik screen generally refers to the character symbols on the solder mask layer, like component name, component symbols, component pins and copyright, to facilitate circuit welding and  error-checking in the future.


D.Paste Mask Layer: includes the top paste and the bottom paste. It refers to the surface mounted pads that we can see.This layer machine is used in mounting, corresponding to all pads of the assembly components. This layer is useful for HASL and welding stencil.


E: Solder Mask: It includes top solder and bottom solder, referring to the layer to be covered with green oil. This layer is not soldering tin, to prevent short circuit in the welding. Solder mask is automatically generated to match the pads in the design process .

F. Mechanical Layers: The maximum is 16 layers. Designing a double layer board only requires to use only the default option: Mechanical Layer 1. Mechanical layer is to define the appearance of the PCB board, which is generally used to set the board dimensions, data marks, alignment marks, assembly instructions and other mechanical information.  LAYER1 is usually regard as shape layer. Other Layer2 / 3/4 and etc. can be used to marking the mechanical dimension or special purposes.


G. Multi-layers: All layers of the PCB. In general, the pads and vias should be arranged in multiple layers. If the layer is closed, the pads and vias can not be displayed.