Multi-corner sign-off

Multi-corner sign-off. The same path is signed off at every corner. Its delay scales with the corner (process, voltage, temperature): setup is worst at the slow corner, hold is worst at the fast corner, and sign-off must pass both checks at every corner.

• Hold does not depend on the clock period. Sliding the period alone can never fix the fast-corner hold violation you start with. You have to add min-delay (a hold buffer) on the path until the fast-corner hold slack turns positive.
• But that added delay lengthens the slow-corner path, so it raises the period you need to still meet setup. Over-add and the slow corner fails setup.

Balance the two knobs (period and added min-delay) so every corner meets setup and hold, then Submit design. Less added delay and a faster clock score higher.