Improving Power Grid Reliability with Power Integrity Analysis and Electromigration Fixing

Electromigration is a severe reliability issue of the power grid network.Due to the increase in the integration and current density of the chip,the margin for electromigration optimization in power grid design is shrinking.However,the traditional design of the power grid network ignores the comprehensive analysis of electromigration and voltage drop,which will cause design over-constrained.In order to avoid the above problems,a power grid optimization method based on sensitivity analysis of via is presented.First,the adjoint matrix method is used to verify the impact of the sensitivity of the vias on electromigration and voltage drop.Then a gradient optimization strategy is formulated for the critical vias with the structure of the power grid network to avoid over-optimization of electromigration.Finally,the configuration of the via array structure is adopted to improve the reliability of the via array.The IBM benchmarks verify the proposed analysis method through numerical experiments on a server with 32 cores.The experimental results show that compared with the full-via optimization strategy,proposed method achieves electromigration optimization at a minimal area cost,and after co-optimization,the circuit has no IR drop violation.