Wafer Defect Classification
Classify known defects and flag unfamiliar anomalies—even when labeled examples are scarce.
SEM images present a difficult classification problem: defect classes are unevenly represented, labeled examples may be scarce, and scratches or particles can vary substantially in appearance. A conventional classifier may also force unfamiliar anomalies into known categories.
We implemented separate stages for anomaly localization, region analysis, defect-specific classification and unknown-defect flagging. Geometric features support scratch analysis, while different visual characteristics are used for foreign particles. Each stage used a method suited to the target defect instead of relying on one general-purpose classifier.
This architecture addresses limited training data and the need to flag anomalies outside the defined taxonomy. It gives inspection teams a clearer basis for reviewing known defects and unfamiliar anomalies.
