Constraints for PVT Corners

Normally Best/Worst PVT means the Fastest/Slowest operating condition of the circuit: typical Best(fastest) PVT is {process: fast, voltage: low, temperature: low} while worst  (slowest) PVT is {process: slow, voltage: high, temperature: high }.

However, recent technology process encounters inverse temperature effect, where cells might function faster at certain high temperature than low temperature, Thus it is suggested that you consult with the cell library provider on what PVT is fastest & slowest.


Notes:
The process fast means, that all transistors on the chip have combination of parameters which gives the minimum cell delay.

Also, We should know about RC corners. The width and thickness of wires (metal) are also may vary from chip to chip ( even on one chip:).  So , for the setup check, we should use RCWorst corner for extraction and one of PVT corners that gives you the max cell delay.