On estimation of NBTI-Induced delay degradation

NBTI, which is one of well-known aging phenomena, brings delay degradation in deep submicron VLSIs. In order to detect NBTI-induced delay faults, we need to estimate delay degradation and apply delay test for the circuit in the field. This paper discusses on estimation of NBTI-Induced delay degradation. We first analyze the effect of the delay degradation, and then give a procedure of path selection in which long paths after the delay degradation are selected for the delay test in the filed. Experimental results show that estimation of delay degradation significantly affects path selection, and accurate estimation is important for the test.