Li Ding: As technology scales down to 5-nanometer and below, we are now down to 3- and 2-nanometer designs, so the variability with respect to nominal values becomes much bigger. Coping with the variability is becoming a much more important topic, so there is a strong need to deal with the variability in all dimensions, including process. One example is high-sigma requirements for automotive applications. Another example, in the dimension of voltage, is the time impact with respect to IR drop. Finally, the dimension of temperature is particularly important for 3DIC.
So, if designers do not do anything and stay with their traditional timing margin-based approach for signoff safety, they are really leaving a lot of PPA (power, performance, area) on the table.