Dynamic IR-Drop Prediction Through a Multi-Task U-Net with Package Effect Consideration

Dynamic IR drop analysis is a critical step in the design signoff stage for verifying the power integrity of a chip. Since the analysis is extremely time-consuming, it has led to the emergence of machine learning (ML)-based methods to expedite the procedure. While previous ML approaches have demonstrated the feasibility of IR drop prediction, they often neglect package effects and do not address diverse IR criteria for memory and standard cells. Thus, this paper introduces a novel ML-based approach designed for a fast and accurate prediction of multi-type IR drop, considering package effects. We develop new package-related features to account for the package impact on IR drop. The proposed model is based on a multitask U-net architecture that not only predicts two types of IR drops simultaneously but also increases prediction accuracy through comprehensive learning. To further enhance the model performance, we introduce the Input Fusion Block (IFB), which unifies units across channels within the input feature maps, leading to improved prediction accuracy. The experimental results show the across-pattern transferability of the proposed IR drop prediction method, demonstrating an RMSE of less than SmV and an MAE of less than 2mV on the unseen simulation patterns. Additionally, our proposed method achieves a 5X speedup compared to the commercial tool.