Pseudopin assignment with crosstalk noise control

This paper presents a new pseudopin assignment (PPA) algorithm with crosstalk noise control in multilayer gridless general-area routing. We propose a two-step approach that considers obstacles and minimizes the weighted sum of total wire length and the estimated number of vias under crosstalk noise constraints. We test our algorithms on a set of MCM examples and a set of standard-cell examples. Without crosstalk noise control in PPA, the average noise in the MCM test cases after detailed routing is 0.13-0.22 V/sub DD/ with up to 11% of nets larger than 0.3 V/sub DD/. However, if the noise constraint of each net is set to 0.3 V/sub DD/ in PPA, the average noise in each case reduces to 0.11-0.15 V/sub DD/ (15%-31% reduction) with no crosstalk noise violations. Most of the nets in our standard-cell test cases do not have noise problems. Our PPA algorithms still give better noise distributions and have 1%-10% noise reduction on the global nets in these standard-cell test cases. Even without ripup and reroute, the detailed routing completion rate is 93%-99% and the average vias per net is only 0.7-1.4 for our MCM test cases and 1.0-1.7 for our standard-cell test cases.