Process variation robust clock tree routing

As the minimum feature sizes of VLSI circuits get smaller while the clock frequency increases, the effects of process variations become significant. We propose a UST/DME based approach to perform simultaneous nonzero clock skew scheduling and clock tree routing, taking into consideration the effects of process variations on clock skews. Our approach ensures that the generated clock tree has a high tolerance to process variations while minimizing the total capacitance of the clock tree, which is proportional to the total wirelength and the total number of buffers. Monte Carlo simulations show that our approach generates clock trees that are highly tolerant to process variations.