Layout-dependent aging mitigation for critical path timing

Layout-dependent effects (LDEs) are becoming increasingly important as technology node continues to shrink into the regime of FinFET transistors. Prior LDE studies mainly focus on accurate transistor modeling and fast circuit performance evaluations at the early lifetime of a design. Few studies have been performed on the layout dependency of the circuit aging towards the end of life (EOL). This study demonstrates that, due to transistor-level layout-dependent aging (LDA) behaviors, circuit-level timing degradations are greatly impacted by layout configurations, including length of diffusion and oxide spacing. In this paper, we propose the first circuit-level aging mitigation framework to improve the critical-path timing towards the EOL. Our framework features comprehensive LDA evaluations for standard cell timing, which shows that multiple-row height cells lead to worse EOL timing than single-row height cells due to length-of-diffusion effects. We further propose a min-cost-flow-based placement approach to concurrently allocate the oxide spacing among neighboring standard cells, which generates much better EOL timing than a conventional greedy approach. Experimental results demonstrate that under the concurrent approach in the proposed aging mitigation framework, the total and worst negative slacks for EOL timing are on average reduced by 42% and 25%, respectively.