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Except for component pin holes, mechanical holes, heat dissipation holes, and test holes in various through holes of PCB, other via holes (such as Via Hole) do not need to be exposed, all require solder mask plug holes, especially HDI high-density connection technology. Since it has become more and more dense, there are more and more VIP holes and VBP holes on PCB boards for packaging, and more and more via plug oils are required, so what are the advantages of using solder mask holes, then let’s introduce one time
The green oil plug hole is to plug the via hole with green oil, generally two-thirds of it is filled, and it is better not to transmit light. Generally, if the via hole is large, the size of the ink plug hole is different according to the manufacturing capacity of the board factory. Generally, the hole below 16mil can be plugged, and the larger hole should consider whether the board factory can plug it.
1. The plug hole can prevent possible short circuits caused by fine-pitch devices (such as BGA). This is the reason for the via fortress hole under the BGA in the design process. Because there is no plug hole, there is a case of short circuit.
2. The plug hole can prevent the tin from passing through the component surface through the through hole to cause a short circuit when the PCB is wave soldered; this means that there is no via or a via in the range of the wave soldering design area (generally the soldering surface is 5mm or more) The reason for the plug hole treatment.
3. Avoid flux residue in the vias.
4. After the surface mounting of the electronics factory and the assembly of the components are completed, the PCB must be vacuumed on the testing machine to form a negative pressure before it is completed.
5. Prevent the surface solder paste from flowing into the hole and cause virtual soldering, which affects the placement; this is most obvious in the heat dissipation pad and the via hole.
6. Prevent the tin bead from popping up during wave soldering, causing short circuit.
7. The plug hole will help the SMT process to a certain extent.
