ATM: A High Accuracy Extracted Timing Model for Hierarchical Timing Analysis

ABSTRACTAs technology advances, the complexity and size of integrated circuits continue to grow. Hierarchical design flow is a mainstream solution to speed up timing closure. Static timing analysis is a pivotal step in the flow but it can be timing-consuming on large flat designs. To reduce the long runtime, we introduce ATM, a high-accuracy extracted timing model for hierarchical timing analysis. Interface logic model (ILM) and extracted timing model (ETM) are the two popular paradigms for generating timing macros. ILM is accurate but large in model size, and ETM is compact but less accurate. Recent research has applied graph compression techniques to ILM to reduce model size with simultaneous high accuracy. However, the generated models are still very large compared to ETM, and its efficiency of in-context usage may be limited. We base ATM on the ETM paradigm and address its accuracy limitation. Experimental results on TAU 2017 benchmarks show that ATM reduces the maximum absolute error of ETM from 131 ps to less than 1 ps. Compared to the ILM-based approach, our accuracy differs within 1 ps and the generated model can be up to 270x smaller.