US Patent 7228193 Methods for detecting structure dependent process defects

Semiconductor devices formed on wafers are inspected using a master wafer. A subject wafer of a semiconductor design is provided. The subject wafer has dies wherein semiconductor devices of the semiconductor design are formed and at a stage of fabrication. A current layer of the subject wafer is scanned to obtain a scanned layer/image. A master wafer comprising individual wafer/layer maps is obtained. The scanned layer is compared with a corresponding layer map. Matching and non-matching defects are identified from repetitive defects within the corresponding layer map and defects within the scanned layer. The matching defects are reviewed to classify and or identify causality. The master wafer is then updated.