Abstract
Owing to the configuration of cavity up and stacked die packaging and the requirements of backside analysis, both packaging types require similar sample preparation steps. This article describes the failure analysis (FA) process to be applied with cavity up and stack die packages. The FA process flow includes testing to determine the nature of the failure, failure correlation to chip and/or internal circuitry, die preparation for repackaging, die repackaging in a cavity down configuration, automated test equipment (ATE) testing to verify the integrity of the pre-packaging failure mode, backside thinning, global fault isolation, backside reconstruction, and defect identification by front side deprocessing. ATE FA can often be performed using special analysis modes and the modification of the test software to put tester in a halt or a loop during fault isolation. When this is completed, global FA techniques can be used. The article also presents a case study on the successful repackaging efforts of cavity up packages.
