electromigration modeling

**Electromigration modeling** is the **physics-based prediction of interconnect atom transport under high current density and elevated temperature** - it estimates void and hillock formation risk in metal lines and vias so routing and current limits remain safe over product life. **What Is Electromigration modeling?** - **Definition**: Model of metal mass transport driven by electron momentum transfer under sustained current. - **Key Failure Forms**: Void growth causing opens and hillock formation causing shorts in dense interconnect. - **Main Stress Variables**: Current density, temperature, line geometry, and microstructure quality. - **Standard Outputs**: Mean time to failure and confidence-bounded lifetime for each routed segment. **Why Electromigration modeling Matters** - **Power Grid Integrity**: EM is a major long-term risk for high-current rails and clock trunks. - **Layout Rule Control**: Current density constraints and via redundancy depend on EM model accuracy. - **Mission Profile Fit**: Activity and temperature profiles determine true lifetime stress exposure. - **Advanced Node Pressure**: Narrower lines increase susceptibility to EM-induced failures. - **Qualification Readiness**: Reliable EM signoff is required for automotive and infrastructure products. **How It Is Used in Practice** - **Current Extraction**: Compute segment-level current waveforms from realistic workload vectors. - **Thermal Coupling**: Combine electrical stress with local temperature map for effective stress estimate. - **Design Mitigation**: Add wider metals, extra vias, and current balancing where predicted life is insufficient. Electromigration modeling is **a mandatory guardrail for long-life interconnect reliability** - accurate EM prediction keeps high-current networks functional across full mission duration.