What is PCB solder mask？
Solder mask refers to the part of the PCB that needs to be painted with green oil; because it is a negative output, the actual effect of the part with the solder mask is not painted with green oil, but is tinned and silver-white!
Soldering layer
The paste mask is used in PCBA Manufacturing. It corresponds to the pads of all SMD components. The size is the same as the toplayer/bottomlayer layer. It is used to open the stencil to leak tin. The same applies to Rigid-Flex Board.
Key points
Both layers are used for soldering. It does not mean that one is soldered and the other is green oil; then whether there is a layer refers to the green oil layer, as long as there is this layer on a certain area, it means that the area is What about insulating green oil? For the time being, I haven't encountered such a layer! The PCB board we drew has a solder layer on the pads by default, so the pads on the PCB board are made of silver-white solder. It is not surprising that there is no green oil; but the PCB we drew The wiring part on the board only has the toplayer or bottomlayer layer, and there is no solder layer, but the wiring part on the finished PCB board is coated with a layer of green oil.
That can be understood like this:
1. The solder mask layer means to open a window on the whole piece of solder mask green oil, the purpose is to allow soldering!
2. By default, the area without solder mask must be painted with green oil!
3. The paste mask layer is used for patch packaging! SMT package uses: toplayer layer, topsolder layer, toppaste layer, and toplayer and toppaste are the same size, topsolder is a circle larger than them. DIP package only uses: topsolder and multilayer layer (after some decomposition, I found that the multilayer layer is actually the topsolder, bottomlayer, topsolder, bottomsolder layer overlap in size), and topsolder/bottomlayer is a circle larger than toplayer/bottomlayer.
Question: Is the phrase "the copper skin layer corresponding to the solder layer is tinned or gold-plated only if there is copper" is correct? This sentence was said by a person working in a PCB factory. What he meant was: if you want to make the part painted on the solder layer to be tinned, then the corresponding solder layer must have copper skin (ie : The area corresponding to the solder layer must have part of the toplayer or bottomlayer layer)! Now: I have come to a conclusion: "The copper skin layer corresponding to the solder layer has copper to be tinned or gold plated" is correct! The solder layer represents the area that does not cover the green oil!
mechanical
keepout layer
top overlay
bottom overlay
top paste, the top pad layer
bottom paste bottom pad layer
top solder top solder mask
bottom solder
drill guide，via guide layer
drill drawing
multilayer
The mechanical layer defines the appearance of the entire PCB board. In fact, when we talk about the mechanical layer, we mean the overall appearance of the PCB board. The forbidden wiring layer defines the boundary when we lay out the electrical characteristics of copper. That is to say, after we first define the forbidden wiring layer, in the future wiring process, the wiring with electrical characteristics cannot exceed the forbidden wiring. The boundary of the layer. Topoverlay and bottomoverlay are the silk screen characters that define the top and bottom, which are the component numbers and some characters that we generally see on the PCB. Toppaste and bottompaste are the top and bottom pad layers, which refer to the copper platinum that we can see exposed to the outside. (For example, we drew a wire on the top wiring layer. What we see on the PCB is just It's just a line, it is covered by the whole green oil, but we draw a square or a point on the toppaste layer at the position of this line, the square and this point on the printed board will not have green Oil, but copper and platinum. The two layers of top solder and bottomsolder are just opposite to the previous two layers. It can be said that these two layers are the layers to be covered with green oil, and the multilayer layer is actually almost the same as the mechanical layer. Yes, as the name enyi, this layer refers to all the layers of the PCB board.
The two layers of top solder and bottomsolder are just opposite to the previous two layers. It can be said that these two layers are the layers to be covered with green oil;
Because it is a negative output, the actual effect of the solder mask is not green, but tinned and silver-white!
1 Signal layer (signal layer) such as: Microwave radio frequency board.
The signal layer is mainly used to arrange the wires on the circuit board. Protel 99 SE provides 32 signal layers, including Top layer (top layer), Bottom layer (bottom layer) and 30 MidLayer (middle layer).
2 Internal plane layer (internal power/ground layer, such as 4 Layer Power line Circuits.
Protel 99 SE provides 16 internal power planes/ground planes. This type of layer is only used for multilayer boards, and is mainly used to arrange power and ground wires. 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
Protel 99 SE provides 16 mechanical layers, which are generally used to set the external dimensions of the circuit board, 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 added to other layers to output and display together. Such as 12 Layer Touch Activated Switch Circuits.
4 Solder mask layer (solder mask layer)
Apply a layer of paint, such as solder resist, to all parts other than the pads to prevent tin 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 masks, Top Solder (top layer) and Bottom Solder (bottom layer).
5 Paste mask layer (solder paste protective layer, SMD patch layer)
Its function is similar to that of the solder mask, but the difference is the pad of the corresponding surface-mounted component during machine soldering. Protel99 SE provides two protective layers of solder paste, Top Paste (top layer) and Bottom Paste (bottom layer).
Mainly for SMD Electronic Components on PCB boards. If all Dip (through hole) components are placed on the board, there is no need to export Gerber files on this layer. Before attaching SMD components to the PCB board, solder paste must be applied to each SMD pad. The stencil used for tinning must require this Paste Mask file before the film can be processed.
The most important point of the Gerber output of the Paste Mask layer is to be clear, that is, this layer is mainly for SMD components. At the same time, compare this layer with the Solder Mask described above to find out the different functions of the two, because you can see from the film picture. The two film images are very similar.
6 Keep out layer (prohibited wiring layer)
Used to define the area where components and wiring can be effectively placed on the circuit board. Draw a closed area on this layer as the effective area for routing. Automatic layout and routing is not possible outside this area.
7 Silkscreen layer
The silk screen layer is mainly used to place printed information, such as component outlines and annotations, various annotation characters, etc. Protel 99 SE provides two silk screen layers, Top Overlay and Bottom Overlay. Generally, all kinds of marked characters are on the top silk screen layer, and the bottom silk screen layer can be closed.
8 Multi layer (multi-layer)
The pads and penetrating vias on the circuit board need to penetrate the entire circuit board and establish electrical connections with different conductive pattern layers. Therefore, the system is specially set up with an abstract layer—multilayer. Generally, the pads and vias must be arranged on multiple layers. If this layer is turned off, the pads and vias cannot be displayed.
9 Drill layer
The drilling layer provides drilling information during the circuit board manufacturing process (such as pads and vias need to be drilled). Protel 99 SE provides two drilling layers, Drillgride (drilling indication map) and Drill drawing (drilling drawing).
The difference between solder mask and flux layer
Solder mask: solder mask refers to the part of the board to be painted with green oil; because it is a negative output, the actual effect of the part with solder mask is not painted with green oil, but is tinned and silver-white!
Soldering layer: paste mask, which is used for machine patching. It corresponds to the pads of all patch components. The size is the same as the toplayer/bottomlayer layer. It is used to open the stencil to leak tin.
Key point: Both layers are used for soldering. It does not mean one is soldered and the other is green oil; then whether there is a layer refers to the green oil layer, as long as there is this layer on a certain area, it means this Is the area insulated with green oil? For the time being, I haven't encountered such a layer! The PCB board we drew has a solder layer on the pads by default, so the pads on the PCB board are made of silver-white solder. It is not surprising that there is no green oil; but the PCB we drew The wiring part on the board only has the toplayer or bottomlayer layer, and there is no solder layer, but the wiring part on the finished PCB board is coated with a layer of green oil.
That can be understood like this:
1. The solder mask layer means to open a window on the whole piece of solder mask green oil, the purpose is to allow soldering!
2. By default, the area without solder mask must be painted with green oil!
3. The paste mask layer is used for patch packaging! SMT packaging uses: top layer, top solder layer, top paste layer, and the top layer is the same size as the top paste, and the topsolder is a circle larger than them. DIP package only uses: topsolder and multilayer layer (after some decomposition, I found that the multilayer layer is actually toplayer, bottomlayer, topsolder, bottomsolder layer overlap in size), and topsolder/bottomsolder is a circle larger than toplayer/bottomlayer.
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