Re-using BIST for circuit aging monitoring

Abstract

Bias Temperature Instability (BTI)-induced transistor aging degrades path delay over time and may eventually induce circuit failure due to timing violations. Chip health monitoring is therefore necessary to track delay changes on a per-chip basis. We propose a method to accurately predict the fine-grained circuit-delay degradation with minimal area and performance overhead. It re-uses on-chip design-for-test (DfT) infrastructure to track the severity of run-time stress by periodiclly capturing system state and compacting it using a multiple input signature register (MISR). The captured stress information is fed to a software-based prediction model in realtime. The prediction model is trained offline using support vector regression. Aging prediction based on run-time stress monitoring can be used to proactively activate aging mitigation techniques. Experimental results for benchmark circuits highlight the accuracy of the proposed approach.