CSL: Coordinated and scalable logic synthesis techniques for effective NBTI reduction

Negative Bias Temperature Instability (NBTI) has become a major reliability concern in nanoscale designs. Although several previous studies have been proposed to address the NBTI effect during logic synthesis, their performance is limited because of focusing on a certain logic synthesis stage. Additionally, their complicated algorithms are not scalable to large designs. To tackle this, we propose a coordinated and scalable logic synthesis approach, which integrates techniques at different logic synthesis stages, ranging from subject graph to technology mapping and mapped netlist, to achieve an effective NBTI reduction. To our best knowledge, this is the first work that considers and mitigates NBTI impact in subject graphs, the earlier stage of logic synthesis. Experimental results on industry-strength benchmarks show that our approach can achieve 6.5% NBTI delay reduction with merely 2.5% area overhead on average, while a previous work barely gets NBTI delay reduction when the circuits are optimized beforehand, the circuit sizes are large, and standard cell libraries are richer.