[SOLVED] Remove via pads on external layer

[jasensio1]

Hello everyone.

I have a 4 layer pcb with high speed signals routed on layers 1 and 2, so I'd like to remove unused via pads on layers 3 and 4.

If removing the via pads on layer 4 (bottom layer)...would the holes be properly plated or could it cause a manufacturability issue?

Thanks!!

 

[FvM]

Via pads on top and bottom layer are required for regular through-plated drills, otherwise the vias must be produced as blind vias. Unconnected pads on inner layers will be usually removed anyway.

The usual (less expensive) way to achieve what you want (remove stubs) is backdrilling of vias.

 

[senilicus]

As FvM already stated, the easiest way to do is using blind via's from layer 1 to layer 2. An other option is using a double core construction.
Instead of using one core and two copper foils you can also build a 4 layer board with a double core construction.

Contact your PCB manufacturer. They know it all.

 

[FvM]

I suggested back drilling rather than blind vias, because it avoids a separate through-plating process step.

Backdrilling parameters explained by a PCB manufacturer https://www.multi-circuit-boards.eu/en/pcb-design-aid/mechanics/backdrill.html