关键词: 单元延时, ECO, 非线性延时模型, 时钟树综合

Abstract: In submicron VLSI physical design，how to control complicated path delay accurately in order to meet timing is always a great challenge.In this paper，a new complicated path control method is proposed，which works accurately and quickly by using placement & routing tool Synopsys Astro.The experimental results indicate that this method can achieve better accuracy and faster convergence than traditional ECO（Engineer Change Order） method，and can be widely used in VLSI physical design.

Key words: cell delay, Engineer Change Order（ECO）, nonlinear delay model, Clock Tree Synthesis（CTS）