An improved method for extrapolating worst-case Simulation Program with
Integrated Circuit Emphasis (SPICE) model parameters for an integrated
circuit including manufacturing semiconductor devices, measuring typical
data and worst-case data with respect to various electrical
characteristics of the manufactured devices, determining a set of typical
SPICE model parameters using the typical data, and determining a set of
worst-case SPICE model parameters using the typical data and the
worst-case data. Determining the set of worst-case SPICE model parameters
preferably includes extrapolating statistical model parameters using the
typical data and the worst-case data and determining the set of
worst-case SPICE model parameters using the statistical model parameters.