I want to densely perforate a large PCB with 2.5mm holes.
the board should have copper only on one inside layer (a ground plane).
The outsides of the board (Top and Bottom) should remain free of copper.
It is important that as the holes are drilled through the board, a (very) small copper-free area exists around the holes on the ground plane. In other words, the copper on the ground plane should not reach the hole perimeter, but instead leave a small margin.
What is the best way to do that?