Accurate and efficient evaluation of circuit yield and yield gradients

A method is described for estimating the yield and yield gradient based on a priori geometric approximation of the acceptability region in the disturbance space. Circuit performance macromodeling is used to construct the acceptability region approximation. While yield evaluation can be carried out in either the performance space or parameter space, it is shown that for monolithic integrated circuits, the gradient of yield can only be estimated accurately in the disturbance space.<>