Defect Detection & Classification

Production Systems

ADC systems, integration with inspection tools, and continuous learning

Automatic Defect Classification (ADC)

Automatic Defect Classification (ADC)

ADC systems automatically classify defects in real-time as part of the production inspection flow:

  • Inline ADC: Classification happens on the inspection/review tool itself, immediately after image capture. Low latency but limited compute.
  • Offline ADC: Images are transferred to a server for classification by more sophisticated models. Higher accuracy but adds delay.
  • Hybrid: Fast pre-classification inline, with uncertain cases sent to a more powerful offline system.

Production ADC requirements:

  • Speed: Classify 1,000+ defects per wafer in seconds
  • Accuracy: >95% agreement with expert human classification
  • Purity: Critical defect categories (e.g., "killer defect") must have very high precision — false negatives are costly
  • Adaptability: Models must handle new defect types as processes change

Key Concept: Continuous Learning

Semiconductor processes constantly evolve — new recipes, new materials, new pattern densities. ADC models must be continuously updated with new training data. This requires a pipeline: flag uncertain classifications → expert review → relabel → retrain → redeploy. Active learning prioritizes the most informative samples for human review.

Knowledge Check

Knowledge Check

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What is the key challenge for ADC systems in production?