Mitigation of IR Drop Through Power Delivery Network (PDN) Reinforcement in Critical Zones

Unintentional IR drop, associated with power consumption, poses a significant challenge in integrated circuits (ICs), exacerbated by increasing operating frequencies and decreasing circuit dimensions. This issue becomes particularly complex with a large number of instances. Traditional methods to mitigate IR drop include various techniques for enhancing the power delivery network (PDN). This paper proposes a novel approach to reinforce the PDN at the end of the engineering change order (ECO) phase, emphasizing the importance of routability, which is critically influenced by IC design congestion. Importantly, this method preserves the main structure of the PDN, augmenting it with additional power and ground (PG) connections in critical zones to enhance power delivery. Furthermore, the timing performance of the design is not degraded during this optimization process. Experiments done on timing-critical design to demonstrate that the proposed PDN reinforcement approach can improve the worst-case IR drop from 9.65%. to 4.2%, representing a 43.5% improvement in the post-ECO stage. These findings underscore the efficacy of the proposed method in enhancing power delivery and overall IC performance.