The circuit board includes many types of working levels, such as the signal layer, protective layer, silk printing layer, inner layer, etc. The role of various levels is briefly introduced as follows:

　　⑴ Signal layer: Mainly used to place components or wiring. Protel DXP usually contains 30 middle layers, namely Mid Layer1 ~ Mid Layer30. The middle layer is used to arrange signal lines, and the top and bottom layers are used to place meta components or copper.

　　Protective layer: It is mainly used to ensure that the tinnic is not required on the circuit board, and it is not plated, thereby ensuring the reliability of the circuit board. Among them, Top Paste and Bottom Paste are top -level welded layers and underlying welded layers; Top Solder and Bottom Solder are the protective layers and underlying tiny paste protective layers, respectively.

　　(3) Silk printing layer: It is mainly used to print the flowing water number, production number, and company name of the component on the circuit board.

　　Internal layer: It is mainly used as a signal wiring layer.

　　4 Other layers: mainly include 4 types of layers.

　　Drill Guide (Diamond Palental Positioner): It is mainly used for the position of drilling on the circuit board.

　　Keep-out layer (forbidden wiring layer): It is mainly used to draw the electrical frame of the circuit board.

　　Drill Drawing (drilling layer): It is mainly used to set the drill shape.

　　Multi-layer (multi-layer): It is mainly used to set up multi-faceted layers.