Power Supply Voltage Dependence of Within-Die Delay Variation of Regular Manual Layout and Irregular Place-and-Route Layout

摘要

Dependence of within-die delay variations on power supply voltage (Vdd) is measured down to 0.4 V. The VDD dependence of the within-die delay variation of manual layout and irregular auto place and route (P&R) layout are compared for the first time. The measured relative delay (=sigma/average) variation difference between the manual layout and the P&R layout decreases from 1.56% to 0.07% with reducing Vdd from 1.2 V to 0.4 V, because the random delay variations due to the random transistor variations dominate total delay variations instead of the delay variations due to interconnect length variations at low Vdd.