How to define anti pad clearance for vias

[pedro_uno]

Hello, I am doing my first non-trivial PCB design in KiCad 6. Everything is pretty well routed but my planes are being eaten up by excessive anti pad clearance around vias. I attach a picture.

The vias are 25 mils but the anti-pad clearance is 20 mils. That causes big cutouts in my power and ground planes. I would like that clearance to be about 8 mils. I will probably reduce the size of the via pads too but I know how to do that.

Where do I adjust the via anti pad clearance?

[paulvdh]

Reducing the clearance of the zone itself is indeed one of the settings that influences this, but the clearance will of course never get smaller then the clearance for the netclass that the via itself is in. Some other absolute minimums are the settings in: PCB Editor / File / Board Setup / Design Rules / Constraints

I see your GND zone is on an internal layer of a 6-layer PCB. If you turn off the annular rings for the via’s on the not-connected layers, then you keep more of your GND zone intact. You can do this with:

1. Right click on the Via checkbox in the Selection filter and select “Only vias”.
   
2. Draw a big box around the PCB or [Ctrl + a] to select everything. (All via’s in this case)
3. Press e for Edit to bring up the **Track and Via Properties.
4. Set the Annular rings to Connected layers only
   
   
5. Press b to refill zones and see the results.

I have been searching a bit for a setting to draw new via’s with the annular rings for the unused layers turned off, but I could not find it. I recommend that you make a checklist for things to check before you create gerber files and add this modification for the annular rings of via’s to that checklist.

[pedro_uno]

Thanks guys. I was looking for the via clearance with the via settings. I did find it under the zone settings for my planes and changed it from 20 mils to 5 mils. I also, changed the default routing rule for via spacing on differential signals. Now I can click along, routing differentially without causing big plane cuts.

For more sophisticated designs I will want to remove via annular rings on unconnected planes. Thanks for that tip too.

Let’s go!