IR-Fusion: A Fusion Framework for Static IR Drop Analysis Combining Numerical Solution and Machine Learning

IR Drop analysis for on-chip power grids (PGs) is vital but computationally challenging due to the rapid growth in the integrated circuit (IC) scale. Traditional numerical methods employed by current EDA software are accurate but extremely time-consuming. To achieve rapid analysis of IR drop, various machine learning (ML) methods have been introduced to address the inefficiency of numerical methods. However, the issue of interpretability or scalability has been limiting practical applications. In this work, we propose IR-Fusion, which aims to combine numerical methods with ML to achieve the trade-off and complementarity between accuracy and efficiency in static IR drop analysis. Specifically, the numerical method is used to obtain rough solutions and ML models are utilized to improve accuracy further. In our framework, an efficient numerical solver, AMG-PCG, is applied to get rough numerical solutions. Then, based on the numerical solution, the fusion of hierarchical numerical-structural information representing the multilayer structure of the PG is employed, and an Inception Attention U-Net model is designed to capture details and interaction of features at different scales. To cope with the limitations and diversity of PG designs, an augmented curriculum learning strategy is applied to the training phase. Evaluation of IR-Fusion shows that its accuracy is significantly better than previous ML-based methods while requiring considerably less iteration on solver to achieve the same accuracy compared with numerical methods.