Collecting Scan fails, what’s next? Introduction to Diagnosis: During the life of a device, there is a constant need for Yield monitoring. Design for Manufacturing (DFM) duty is to identify how device design can be improved to maximize production efficiency. Fault Diagnosis and Failure analysis are key elements to the understanding of the mechanisms. Scan testing, as a structural test, is a major source of information to map failures to the design. Scan data collection is mandatory to perform this analysis. It is Automatic Test Equipment (ATE) duty to collect that data at whatever level, from Engineering to Mass Production. This paper will describe how Teradyne collects and reports scan fail information. We will cover STDF scan-specific entries as well as ASCII outputs with ScanFalcon. We will then discuss the next steps and how Design teams process the results reported by the ATE to pinpoint areas of improvement in their design.