How are vias plated?
Vias are plated along with the rest of the circuit board during its regular fabrication process. A thin layer of copper coating is added chemically into the holes and onto the surface of the board through a process called electroless copper deposition. This gives the copper plating a base to build up from.
What is plated through hole?
In through-hole technology, the components are mounted on the PCB board by inserting their leads through the respective hole. When using Plated Through Holes, as the name suggests, the inner wall of the holes is covered with a thin layer of Copper, which makes the entire inner hole area conductive.
How are vias made on a PCB board?
How Are Vias Made? Unless you are at home with a DIY via rivet gun on a 2-layer board, vias are created during the PCB manufacture process. Briefly, holes are drilled through copper pads on the PCB, a chemical is put in the hole to dissolve epoxy on the internal layers to further expose the interior layer copper pads.
How is the surface of a plugged via plated?
The surface of the plugged via is then plated over with copper. The newly plated copper surface is flattened and smoothed (planarized) to be even with the surrounding copper features. You now have a solderable surface mount pad that also passes signal to inner layers eliminating the need to rout the signal to a via on the surface layer.
What’s the best way to fill a via hole?
The recommended material for these processes is a non-conductive epoxy hole fill. Limit your vias to 0.020” maximum diameter to allow the epoxy to fill the hole effectively. For these types, supply your Gerber files with no solder mask openings for the vias in question.
Is there a trick to drilling through vias?
There is no trick to drilling through vias, provided you follow your fabricator’s rules for minimum diameter, maximum aspect ratio (board thickness divided by hole diameter), and adjacency (minimum allowable distance from the edge of one via to the nearest adjacent via). Next come mechanically drilled blind vias.