#426 libs.tech/sg13g2_io: Add nofill zones over IO cells Pull request opened by smunaut Add nofill overlays on the IO cells for all fill layers except for: • Metal2 : There are no big rails on this layer in the cells, so you actually want Metal2 fill • GatPoly : If you have a Activ:nofill, there won't be any GatPoly fill anyway and there is a GFil.i DRC rule that'd be violated. For the zone to be covered, the same area as prBoundary is used except for the Corner cell where one corner is cut. Fixes #423 IHP-GmbH/IHP-Open-PDK