Evaluation of the Quality of N-Detect Scan ATPG Patterns on a Processor

This paper evaluates N-detect scan ATPG patterns for their impact to test quality through simulation and fallout from production on a Pentium 4 processor using 90nm manufacturing technology. An incremental ATPG flow is used to generate N-detect test patterns. The generated patterns were applied in production with flows to determine overlap in fallout to different tests. The generated N-detect test patterns are then evaluated based on different metrics. The metrics include signal states, bridge fault coverage, stuck-at fault coverage and fault detection profile. The correlation between the different metrics is studied. Data from production fallout shows the effectiveness of N-detect tests. Further, the correlation between fallout data and the different metrics is analyzed. 1