Shulou(Shulou.com)06/01 Report--

What is the function of each layer in the PCB board? in view of this question, this article introduces the corresponding analysis and solution in detail, hoping to help more partners who want to solve this problem to find a more simple and feasible method.

Many PCB board design enthusiasts, especially novices, do not fully understand the various layers of PCB design, and do not know its function and usage. Here is a systematic explanation:

1. The mechanical layer of Mechanical is mechanically shaped, that is, the appearance of the entire PCB board. In fact, when we are talking about the mechanical layer, we refer to the shape and structure of the whole PCB board. It can also be used to set circuit board dimensions, data marks, alignment marks, assembly instructions and other mechanical information. This information varies depending on the requirements of the design company or PCB manufacturer. In addition, the mechanical layer can be attached to other layers for output and display.

2. Keep out layer (no wiring layer), which is used to define the area on the circuit board where components and wiring can be effectively placed. Draw a closed area on this layer as a routing effective area, which cannot be automatically laid out and routed outside this area. Forbidden wiring layer is the boundary when we define the copper of electrical characteristics, that is to say, after we define the prohibited wiring layer first, the lines with electrical characteristics cannot exceed the boundary of the prohibited wiring layer in the future cloth process, and it is often customary to use the Keepout layer as a mechanical layer, which is actually wrong, so it is suggested that we should make a distinction. Otherwise, the board factory will change the properties for you every time it is produced.

3. Signal layer (signal layer): the signal layer is mainly used to arrange the wires on the circuit board. Includes Top layer (top layer), Bottom layer (bottom layer) and 30 MidLayer (middle tier). The devices are placed in the Top layer and the bottom layer, and the inner layer is routed.

4, Top paste and Bottom paste is the top layer, bottom solder plate steel mesh layer, and the size of the pad is the same size, this is mainly when we do SMT can use these two layers to carry on the production of steel mesh, just dig a pad size hole in the net, we then put this steel mesh cover on the PCB board, with a brush with solder paste will be very uniform brush on the paste, as shown in figure 2-1.

5. Top Solder and Bottom Solder are the solder resistance layer, which prevents the green oil cover. We often say "open the window". The conventional copper coating or wiring is covered with green oil by default. If we deal with the solder resistance layer accordingly, the green oil will be prevented and the copper will be exposed. As shown in the following figure, you can see the difference between the two:

6. Internal plane layer (Internal Power supply / grounding layer): this type of layer is only used for multi-layer boards, mainly for laying out power lines and ground wires, we call them double-layer boards, four-layer boards and six-layer boards, which generally refers to the number of signal layers and internal power / ground layers.

7. Silkscreen layer (screen printing layer): the screen printing layer is mainly used to place printing information, such as the outline and annotation of components, various annotation characters, etc. Altium provides two screen printing layers, Top Overlay and Bottom Overlay, to place the top screen printing document and the bottom screen printing file respectively.

8. Multi layer (multi-layer): the pads and penetrating holes on the circuit board should penetrate the whole circuit board and establish electrical connection with different electrographic layers, so the system specially sets up an abstract layer-multi-layer. In general, the pad and through hole should be set on multiple layers, if this layer is closed, the pad and through hole can not be displayed.

9. Drill Drawing (borehole layer): the borehole layer provides drilling information during the circuit board manufacturing process (such as pads, holes need to be drilled). Altium provides two drilling layers, Drill gride (drill hole indication) and Drill drawing (drill hole map).

The answer to the question about the role of each layer in the PCB board is shared here. I hope the above content can be of some help to everyone. If you still have a lot of doubts to be solved, you can follow the industry information channel to learn more about it.

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.