Statistical Timing Analysis for IC NBTI Degradation

The patent applies statistical timing analysis during the design phase to predict and account for stress degradation before the IC is fabricated and deployed. By performing timing analysis that incorporates degradation models in advance, the design can be adjusted to ensure reliability over the IC's operational lifetime without requiring complex real-time monitoring or adjustment mechanisms.

The patent modifies timing parameters and degradation models to incorporate stress effects such as NBTI and CHC. By changing the timing analysis to include degradation parameters (e.g., threshold voltage shifts, mobility changes) as functions of stress conditions, the system achieves more accurate reliability assessment while managing complexity through parameterization rather than fundamental architectural changes.

The patent applies different levels of analysis to different transistors based on their criticality and stress exposure. Rather than uniformly analyzing all transistors, the statistical timing analysis identifies and focuses on critical paths and transistors that experience highest stress, applying more detailed degradation modeling where needed and simplified models where acceptable, thus achieving high timing accuracy for critical components without proportionally increasing overall manufacturing time.

The patent performs timing analysis with degradation accounting for a representative sample of critical transistors and paths rather than all transistors. By applying partial analysis to the most critical elements and using statistical generalization for less critical ones, the patent achieves sufficient timing accuracy while significantly reducing the time required compared to exhaustive analysis of every transistor.