Abstract: Accurate critical path delay estimation plays a vital role in reducing unnecessary routing iterations and identifying potentially unsuccessful design runs early in the flow. This study proposes an architecture that integrates graph representations derived from digital complex functional blocks netlist and design constraints, leveraging a Multi-head cross-attention mechanism. This architecture significantly improves the accuracy of critical path delay estimation compared to standard tools provided by the OpenROAD EDA. The mean absolute percentage error (MAPE) of the OpenRoad standard tool—openSTA is 12.60%, whereas our algorithm achieves a substantially lower error of 7.57%. A comparison of various architectures was conducted, along with an investigation into the impact of incorporating netlist-derived information. © Allerton Press, Inc. 2025.