2367

Wafer inspection systems examine patterned or unpatterned wafers for defects and process excursions using optical imaging and analysis. Brightfield inspection tools illuminate the wafer and analyze reflected light to find particles, pattern defects, and other yield-limiting anomalies. Metrology and inspection tools support process control by identifying defectivity trends and by helping engineers decide when additional review or corrective action is needed.

Brightfield wafer inspectors scan the wafer surface and patterned features while optical detectors measure reflected signal differences from expected background behavior. Inspection software segments candidate events, filters nuisance signal, and classifies likely defect types for follow-up review. Automated inspection of this class is commonly used to raise sampling coverage compared with manual microscopy and to feed downstream review steps with defect locations.

Wafer inspection tools are placed at monitoring points around lithography and related pattern transfer steps so that defectivity can be measured before more value is added to the wafer. Inspection commonly follows resist coating, exposure, development, etch, planarization, or clean sequences, depending on the layer and control strategy. The output of inspection often feeds review microscopy, engineering analysis, and process adjustment loops.

The KLA 2367 is applied to critical pattern layers at 65 nm and above. The KLA 2367 is used to detect lithography CD variations, missing contacts, gate etch stringers, STI voids, and copper CMP corrosion. The KLA 2367 is also used for photo cell monitoring to identify lithography-related micro defects before product wafers are committed. The KLA 2367 is used in after-develop inspection to detect poisoned photoresists, micro-bridges, and resist bubbles.^[1]