Abstract: A method for creating a guardband that incorporates statistical models for test environment, system environment, tester-to-system offset and reliability into a model and then processes a final guardband by factoring manufacturing process variation and quality against yield loss.

Abstract: A method and system are provided for determining a guard band voltage differential for testing a microprocessor. The guard band voltage differential approximates microprocessor circuit propagation delay degradation expected to occur over the life of the microprocessor. The system and method are performed by first partitioning a microprocessor into a plurality of cones of n circuit level models. Timing simulation data and degradation data are created to represent, respectively, the timing operation for each of the circuit level model circuit paths, and the hot-electron effects on propagation delay degradation for each of the circuit level models. Propagation delay is identified using this data for each of the circuit paths for the circuit level models at times corresponding to the beginning-of-life and end-of-life of the microprocessor. Propagation delay degradation is calculated as the difference between the propagation delay at these times.

Abstract: A method of assessing the tolerance of a microprocessor to propagation time degradation caused by electromigration effects and hot electron effects is provided. Reference values for interconnection resistance (IR) degradation and drain current (DC) degradation are compute, at nominal fabrication process and microprocessor lifetime application conditions. These results may be tabulated for a plurality of output driver load capacitances. Test IR degradation and test DC degradation values are calculated by scaling the reference IR and DC degradation values, respectively, for actual test conditions. The circuit propagation time and the propagation delay degradation caused by both electromigration and hot electron effects are calculated at process and lifetime environmental conditions.