I think I found a few minor issues in the DRC rules: Minimum Spacing 270 for pdiff_contact too small because of pdiffusion, minimum should be 390(=270+2*60) Fixing minimum_spacing Minimum Spacing 270 for ndiff_contact too small because of ndiffusion, minimum should be 390(=270+2*60) Fixing minimum_spacing Minimum Spacing 390 for pdiff_contact - ndiff_contact too small because of ndiffusion, minimum should be 390(=270+60+60) Fixing minimum_spacing Minimum Spacing 190 for via1 too small because of metal1, minimum should be 260(=140+2*60) Fixing minimum_spacing