An ECO routing algorithm for eliminating coupling-capacitance violations

Engineering change order changes are almost inevitable in the late stages of a design process. Based on an existing design, incremental change is favored since it can avoid considerable efforts of redoing the whole process and can minimize the disturbance on the existing converged design. The coupling-capacitance violation elimination (CVE) problem is addressed. Due to the changes in the multiple layer routing design, the total coupling capacitance on some signal wire segments on a layer may be larger than their allowable bounds after postlayout timing/noise analysis. The target is to find a new routing solution without coupling-capacitance violations under certain constraints, which helps to keep the new design close to the original one. This paper proposes a two-stage algorithm to solve CVE problems, and present optimization strategies to speed up the execution. Experimental results demonstrate the efficiency and effectiveness of this algorithm