Inspection step modeling for defect source tool identification using defectivity control

Rapid Defect source tool identification in semiconductor manufacturing is crucial to improve the product quality and to reduce the production cost. When defect is detected, tool commonality among lots is a proven technique to identify the defect source. The critical element of successful commonality analysis is the multiple entry lots within the same process flow. Hence, since deployment of dynamic sampling strategies, lots selected for inspection are taken from different process flows at different manufacturing levels. This paper proposes an indicator to choose lots within the identical process operation sequences, taken from different process flows, for commonality analysis. Using a sequence alignment algorithm, the process operation sequences are compared to each other in order to calculate the similarity weight. The industrial experiments of the proposed approach shows a significant increase of number of available lots for analysis.