Solder Mask Layer
The solder mask refers to the areas on the board where green oil is applied; since it is a negative output, the areas with solder mask actually do not have green oil but are instead coated with tin, appearing silver-white!
Paste Mask Layer
The paste mask is used during machine placement and corresponds to the pads of all surface mount components. Its size is the same as that of the top layer/bottom layer and is used for opening the stencil for solder paste.
Key Points
Both layers are used for soldering and do not indicate one is for solder and the other is for green oil; however, is there a layer that indicates the area for applying green oil? So far, I have not encountered such a layer! In the PCB we design, the pads on the top layer by default have a solder layer, so it is not surprising that the pads on the produced PCB are coated with silver tin instead of green oil; however, the traces on the PCB we designed only have the top layer or bottom layer and do not have a solder layer, but the traces on the produced PCB are all coated with a layer of green oil.
Thus, it can be understood as:
1. The solder mask layer means to open windows on the entire area of solder mask green oil to allow for soldering!
2. By default, areas without a solder mask layer must be coated with green oil!
3. The paste mask layer is used for surface mount packaging! SMT packaging uses: top layer, top solder layer, top paste layer, and the top layer and top paste are the same size, while the top solder is larger. DIP packaging only uses: top solder and multilayer (after some decomposition, I found that the multilayer actually overlaps the sizes of the top layer, bottom layer, top solder, and bottom solder), and the top solder/bottom solder is larger than the top layer/bottom layer.
Question: “The statement ‘the solder layer corresponds to the copper layer must have copper to be plated with tin or gold’ is correct?” This statement was made by someone working in a PCB production factory, meaning: to achieve the effect of plating tin in the area drawn on the solder layer, the corresponding solder layer must have copper (i.e., the area corresponding to the solder layer must have parts of the top layer or bottom layer)! Now, I conclude that: “The statement ‘the solder layer corresponds to the copper layer must have copper to be plated with tin or gold’ is correct! The solder layer indicates the area that does not cover green oil!
Mechanical Layer, mechanical layer
Keepout Layer prohibits wiring layer
Top Overlay, top silkscreen layer
Bottom Overlay, bottom silkscreen layer
Top Paste, top pad layer
Bottom Paste, bottom pad layer
Top Solder, top solder mask layer
Bottom Solder, bottom solder mask layer
Drill Guide, drill guide layer
Drill Drawing, drill hole layer
Multilayer, multilayer
The mechanical layer defines the overall appearance of the PCB board. When we refer to the mechanical layer, we are actually talking about the overall shape of the PCB. The keepout layer defines the boundaries when laying out the electrical characteristics of copper, meaning that once we define the keepout layer, the lines we lay out with electrical characteristics cannot exceed the boundaries of the keepout layer. The top overlay and bottom overlay define the silkscreen characters on the top and bottom layers, which are generally the component numbers and some characters we see on the PCB. The top paste and bottom paste are the top and bottom pad layers, which refer to the visible copper pads. (For example, if we draw a wire in the top layer, what we see on the PCB is just a wire that is covered by the entire green oil, but if we draw a square or a dot on the top paste layer at the position of this wire, the square and dot on the produced board will not have green oil but will be copper pads. The top solder and bottom solder layers are the opposite of the previous two layers; these two layers are the ones that cover the green oil. The multilayer layer is actually similar to the mechanical layer, as the name suggests, this layer refers to all layers of the PCB board.
The distinction between the solder mask layer and the paste mask layer:
The solder mask layer: solder mask refers to the area on the board that needs to be coated with green oil; since it is a negative output, the areas with solder mask actually do not have green oil but are instead plated with tin, appearing silver-white!
The paste mask layer: paste mask is used during machine placement and corresponds to the pads of all surface mount components, and its size is the same as that of the top layer/bottom layer and is used for opening the stencil for solder paste.
Key Points: Both layers are used for soldering and do not indicate one is for solder and the other is for green oil; however, is there a layer that indicates the area for applying green oil? So far, I have not encountered such a layer! In the PCB we design, the pads on the top layer by default have a solder layer, so it is not surprising that the pads on the produced PCB are coated with silver tin instead of green oil; however, the traces on the PCB we designed only have the top layer or bottom layer and do not have a solder layer, but the traces on the produced PCB are all coated with a layer of green oil.
Thus, it can be understood as:
1. The solder mask layer means to open windows on the entire area of solder mask green oil to allow for soldering!
2. By default, areas without a solder mask layer must be coated with green oil!
3. The paste mask layer is used for surface mount packaging! SMT packaging uses: top layer, top solder layer, top paste layer, and the top layer and top paste are the same size, while the top solder is larger. DIP packaging only uses: top solder and multilayer (after some decomposition, I found that the multilayer actually overlaps the sizes of the top layer, bottom layer, top solder, and bottom solder), and the top solder/bottom solder is larger than the top layer/bottom layer.
Source: EETOP
