考虑多角的预布线阶段 SI-Aware 线路时序预测.pdf

1、SI-Aware Wire Timing Prediction at Pre-Routing Stage with Multi-Corner ConsiderationYushan Wang1,Xu He1,Renjun Zhao1,Yao Wang2,Chang Liu2,Yang Guo21Hunan University,2National University of Defense TechnologyChangsha,China30th Asia and South Pacific Design Automation ConferenceASP-DAC 2025Outline0102

2、0304MotivationProblem FormulationOverviewWire Timing Prediction 05Experimental Result2 Signal Integrity(SI)Effect Crosstalk and noise propagation SI analyze typically in post-routing,electrical and logical Challenges in Pre-Routing Timing Absence essential physical info,i.e.,routing,congestionMotiva

3、tion3 Timing analyze throughout entire design flow Earlier the intervention stage,greater the room for optimizationMotivation4(a)Difference between Elmore and sign-off at typical corner(b)Path delay among different PVT corners.Solution Develop SI-aware prediction model Multi-corner considerationPre-

4、routing wire timing challenges:Lack of routing infoModel oversimplification Elmore vs.Sign-Off,gap 150 psEven worse in multi-corner variationsProblem Formulation:Input:layout,cell libraryGolden timing reports in SI mode under multi-corners(For training and evaluation)Output:Wire delay,corresponding

5、path AT,and critical pathObjective:Minimizes the discrepancy between prediction and the golden timing.SI-Timing Prediction Formulation5Prior Machine Learning Predictions:Trade-off between accuracy and computationally expensivePre-placement stagePlacement stagePost-routing and sign-off stageOverview6

6、Framework of our method Key Techniques:Feature Selection&Extraction Method Routing info unavailable at pre-routingLookahead RC Network:based on Steiner tree-based trial routing7Feature selection is critical,three kinds factors:Net-itself feature:Basic RC infoNeighboring nets related feature:SI-Aware