Great question @User we have an Antenna diode as a standard cell in our library. Normally, you have a separate flow to handle placing diodes to avoid antenna effects with poly. I believe on early SoC designs that were done previously, I believe they just placed them everywhere. We do not do that within our tool and just run the antenna flow. The LEF file is set up correctly within our library for antenna placement - not sure about within SKW (I am leaning towards that its not). We also tested our antenna insertion and it worked perfectly within our tool. So, I guess I do not really know how they eliminate them other than manually from what you are asking. But, in our library, you would use the antenna flow within the pnr tool.