Wafer/package test mix for optimal defect detection

This paper presents the results of an extensive data collection study where production wafer and package test data are examined from the point of view of determining an optimal mix of wafer and package tests to achieve the combined goals of high defect coverage and rapid yield learning, while simultaneously examining the possibility of using lower cost ATE. Results for at-speed tests show that for some types of parts reduced speed transition fault testing can be very effective.