NBTI and Leakage Reduction Using an Integer Linear Programming Approach

As technology scales, negative bias temperature instability (NBTI) becomes one of the primary failure mechanisms for VLSI circuits. Meanwhile, the leakage power increases dramatically as the supply/threshold voltage continues to scale down. These two issues pose severe reliability problems for CMOS devices. Because both the NBTI and leakage are dependent on input vector of the circuit, we present an input vector control (IVC) method based on an integer linear programming (ILP) approach. A novel NBTI and leakage reduction criterion function as well as an ILP formulation are presented to simultaneously minimize the delay degradation and leakage power. Our proposed ILP formulation can be generated adaptively for different circuits that can help the designers find the optimal input vector conveniently. In addition, the proposed method is combined with the supply voltage assignment technique to further reduce delay degradation and leakage power. Experimental results on various circuits show the effectiveness of the proposed method.