AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |
Back to Blog
This includes component pin holes, non-plated holes, and vias. Once the different board layers have been composited together, all of the thru-holes are drilled.But for standard thru-hole vias, the process can be summarized like this: There are also different processes for blind and buried vias as well. Microvias are different in that they are laser drilled and depending on which layers they are on, the process will vary. Vias are plated along with the rest of the circuit board during its regular fabrication process. Now that we’ve looked at what the different types of vias are, let’s see how they are fabricated.Īn example of the different types of vias that can be used in PCB design Now the Question: How are PCB Vias Plated? To remedy this, high-speed designs will often have their vias back-drilled to remove the unused portion. For example, a thru-hole via in a 10 layer board that only connects the first two layers will still have eight layers that may radiate interference. Another important point for PCB designers to remember is that vias can have a negative effect on the signal performance of the board. The via aspect ratio for a standard 0.062-inch thick circuit board is typically 10:1, which means that the fabricator will not drill anything smaller than a 0.006 hole in the board. Via drill sizes also need to be calculated with the correct aspect ratio in order to be drilled successfully. This can happen as mechanical drills tend to wander slightly during the fabrication process. Vias need a sufficient annular ring around the hole to prevent breakout during drilling. Plugging the vias with non-conductive materials is a better solution while filling the vias with conductive materials will give the best thermal performance although it is also the most expensive choice. This can potentially outgas during the soldering process and either break solder joints or spray solder causing shorts to nearby circuits. Tenting a via with solder mask is one option as long as the via isn’t used in a pad, but it also allows pressure to build up in the barrel of the via. Vias that aren’t enhanced like this can wick solder down into them, especially if they are being used in a pad. These enhancements are known as tenting, plugging, or filling. Vias are often enhanced later in the fabrication process in order to increase their thermal conductivity or to improve their assembly yields. Microvias can be stacked on top of each other, stacked on a buried via, or staggered depending on the needs of the design. A microvia only spans 2 layers, and its smaller size makes it a better fit for high-density PCB designs. ![]()
0 Comments
Read More
Leave a Reply. |