In PCB design, mastering the meaning of each layer is the most basic thing. Are you ok with it?

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In PCB design, mastering the meaning of each layer is the most basic thing. Are you ok with it? [Copy link]

Solder mask: solder mask refers to the part of the board that needs to be painted with green paint; because it is a negative film output, the actual effect of the part with solder mask is not green paint, but tinned, which is silvery white!

Key points: Both layers are used for tinning and welding. It does not mean that one is for tinning and the other for green paint. So is there a layer that refers to the layer for green paint? As long as this layer is present in a certain area, it means that this area is covered with insulating green paint? A: I haven't come across such a layer yet! The pads on the PCB boards we draw have a solder layer by default, so the pads on the manufactured PCB boards are coated with silver-white solder, and it's not surprising that there is no green oil on them; but the traces on the PCB boards we draw only have the toplayer or bottomlayer layer, and no solder layer, but the traces on the manufactured PCB boards are all coated with a layer of green oil.

Question: Is it correct to say that the copper layer corresponding to the solder layer will be tinned or gold plated only if there is copper on the copper layer corresponding to the solder layer? Answer: This sentence was said by a person who works in a PCB factory. What he meant was that if you want to make the part drawn on the solder layer look like tin-plated, then the corresponding solder layer part must have copper skin (that is, the area corresponding to the solder layer must have a toplayer or bottomlayer part)! Now: I have come to a conclusion: "The copper skin layer corresponding to the solder layer will be tinned or gold-plated only if it has copper" is correct! The solder layer refers to the area not covered with green oil!

mechanical,mechanical layer[ /color]

keepout layer prohibits wiring layer

[size= 12px]top overlaytop silkscreen layer

bottom overlaybottom silkscreen layer

top paste,top solder pad layer

bottom paste bottom pad layer

top solder top solder mask layer

bottom solder bottom solder mask layer

drill guide,drill drawing,drill drawing,drill drawing,multilayer,multilayer,multilayer,

"]The mechanical layer defines the appearance of the entire PCB board. In fact, when we talk about the mechanical layer, we are referring to the shape structure of the entire PCB board. The forbidden wiring layer defines the boundary when we lay out the copper with electrical characteristics. That is to say, after we define the forbidden wiring layer first, in the subsequent laying process, the wires with electrical characteristics laid out cannot exceed the boundary of the forbidden wiring layer. Topoverlay and bottomoverlay are the silk-screen characters that define the top and bottom layers, which are the component numbers and some characters we usually see on PCB boards.

Toppaste and bottompaste are the top and bottom pad layers, which refer to the copper platinum that we can see exposed outside. (For example, we draw a wire on the top wiring layer. What we see on the PCB is just a wire. It is covered by the entire green oil. But if we draw a square or a point on the toppaste layer at the position of this wire, the square and the point on the printed board will not have green oil, but copper platinum.

top solder and bottom solder are just the opposite of the previous two layers. It can be said that these two layers are the layers to be covered with green oil. The multilayer layer is actually similar to the mechanical layer. As the name implies, this layer refers to all the layers of the PCB board.

top The solder and bottomsolder layers are just the opposite of the previous two layers. It can be said that these two layers are the layers to cover the green paint. Because it is a negative film output, the actual effect of the solder mask part is not green paint, but tin plating, which is silver-white!

1 Signal layer(Signal layer)

The signal layer is mainly used to arrange the wires on the circuit board. Protel 99 SE provides 32 signal layers, including Top layer, Bottom layer and 30 MidLayer.

[p=26, null, 2 Internal plane layer(internal power/ground layer)

Protel 99 SE provides 16 internal power/ground layers. This type of layer is only used for multi-layer boards, mainly for arranging power lines and ground lines. We call double-layer boards, four-layer boards, and six-layer boards, generally referring to the number of signal layers and internal power/ground layers.

3 Mechanical layer (mechanical layer)

Protel 99 SE provides 16 mechanical layers, which are generally used to set the board's 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. Executing the menu command Design|MechanicalLayer can set more mechanical layers for the circuit board. In addition, the mechanical layer can be attached to other layers for output display.

4 Solder mask layer (solder mask)

Apply a layer of coating, such as solder mask, to the parts other than the pads to prevent tinning on these parts. The solder mask is used to match the pads during the design process and is automatically generated. Protel 99 SE provides two solder mask layers: Top Solder (top layer) and Bottom Solder (bottom layer).

5 Paste mask layer (solder paste protective layer, SMD patch layer)

It has a similar function to the solder mask, except that it corresponds to the pads of the surface-mounted components during machine soldering. Protel99 SE provides two solder paste protection layers: Top Paste (top layer) and Bottom Paste (bottom layer).

It is mainly for SMD components on PCB boards. If the board is full of Dip (through-hole) components, there is no need to output Gerber files for this layer. Before attaching SMD components to the PCB board, solder paste must be applied to each SMD pad. The steel mesh used for tinning must require this Paste Mask file so that the film can be processed.

The most important thing to know about the Gerber output of the Paste Mask layer is that this layer is mainly for SMD components. At the same time, compare this layer with the Solder Mask introduced above to clarify their different functions, because the two film images are very similar.

6 Keep out layer(No wiring layer)

It 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 the wiring effective area. Automatic layout and routing cannot be performed outside this area.

[ size=12px]7 Silkscreen layer(silkscreen layer)

The silk screen layer is mainly used to place printed information, such as the outline and annotation of components, various annotation characters, etc. Protel 99 SE provides two silk screen layers: Top Overlay and Bottom Overlay. Generally, various annotation characters are on the top silk screen layer, and the bottom silk screen layer can be closed.

[ size=12px]8 Multi layer(multi-layer)

The pads and through-holes on the circuit board need to penetrate the entire circuit board and establish electrical connections with different conductive graphic layers. Therefore, the system specifically sets up an abstract layer - multi-layer. Generally, pads and vias are set on multiple layers. If this layer is closed, pads and vias cannot be displayed.

[ size=12px]9 Drill layer(drilling layer)

The drilling layer provides drilling information in the circuit board manufacturing process (such as pads and vias that need to be drilled). Protel 99 SE provides two drilling layers: Drillgride (drilling indication diagram) and Drill drawing (drilling diagram).

The distinction between solder mask and solder assist layer

[p=26, null, : left]

Solder mask refers to the part of the board that needs to be painted green. Because it is a negative film output, the actual effect of the part with solder mask is not to paint green, but to be tinned, which is silver-white!

Paste mask, is used when the machine is mounted on the chip. It corresponds to the solder pads of all the chip components. Its size is the same as the toplayer/bottomlayer layer. It is used to open the steel mesh to leak tin.

Key points: Both layers are used for tinning and welding. It does not mean that one is for tinning and the other for green paint. So is there a layer that refers to the layer for green paint? As long as this layer is present in a certain area, it means that this area is covered with insulating green paint? A: I haven't come across such a layer yet! The pads on the PCB boards we draw have a solder layer by default, so the pads on the manufactured PCB boards are coated with silver-white solder, and it's not surprising that there is no green oil on them; but the traces on the PCB boards we draw only have the toplayer or bottomlayer layer, and no solder layer, but the traces on the manufactured PCB boards are all coated with a layer of green oil.

That can be understood like this:

1. The meaning of the solder mask layer is to open a window on the entire piece of green solder mask to allow welding! 2. By default, all areas without solder mask should be painted green!

"]3. The paste mask layer is used for SMD packaging!

SMT packaging uses: top layer, top solder layer, top paste layer, and the top layer and top paste are the same size, and the topsolder is one circle larger than them. DIP packaging only uses: topsolder and multilayer layers (after some decomposition, I found that the multilayer layer is actually toplayer, bottomlayer, topsolder, and bottomsolder layers overlap in size), and topsolder/bottomsolder is one circle larger than toplayer/bottomlayer.

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Russel99

Learned,