Confidence Estimation in Non-RF to RF Correlation-Based Specification Test Compaction

Several existing methodologies have leveraged the correlation between the non-RF and the RF performances of a circuit in order to predict the latter from the former and, thus, reduce test cost. While this form of specification test compaction eliminates the need for expensive RF measurements, it also comes at the cost of reduced test accuracy, since the retained non-RF measurements and pertinent correlation models do not always suffice for adequately predicting the omitted RF measurements. To alleviate this problem, we develop a methodology that estimates the confidence in the obtained test outcome. Subsequently, devices for which this confidence is insufficient are retested through the complete specification test suite. As we demonstrate on production test data from a zero-IF down-converter fabricated at IBM, the proposed method outperforms previous defect filtering and guard banding methods and enables a more efficient exploration of the tradeoff between test accuracy and number of retested devices.