YIELD MODELING OF ACOUSTIC CHARGE-TRANSPORT TRANSVERSAL FILTERS

This paper presents a yield model for acoustic charge transport transv ersal filters. This model differs from previous IC yield models in tha t it does not assume that individual failures of the nondestructive se nsing taps necessarily cause a device failure. A redundancy in the num ber of taps included in the design is explained. Poisson statistics ar e used to describe the tap failures, weighted over a uniform defect de nsity distribution, A representative design example is presented. The minimum number of taps needed to realize the filter is calculated, and tap weights for various numbers of redundant taps are calculated. The critical area for device failure is calculated for each level of redu ndancy. Yield is predicted for a range of defect densities and redunda ncies. To verify the model, a Monte Carlo simulation is performed on a n equivalent circuit model of the device. The results of the yield mod el are then compared to the Monte Carlo simulation. Better than 95% ag reement was obtained for the Poisson model with redundant taps ranging from 30% to 150% over the minimum.