inline defect inspection

**Inline defect inspection** checks **wafers during processing** — catching defects early before they propagate through subsequent steps, enabling faster feedback and preventing yield loss. **What Is Inline Inspection?** - **Definition**: Defect inspection during wafer processing. - **Timing**: After critical process steps (lithography, etch, CMP). - **Purpose**: Early defect detection, fast feedback, yield protection. **Why Inline Inspection?** - **Early Detection**: Catch defects before they propagate. - **Fast Feedback**: Immediate process correction. - **Yield Protection**: Stop bad wafers before more processing. - **Root Cause**: Identify which step caused defects. **Inspection Points**: After lithography (pattern defects), after etch (etch residue), after CMP (scratches, dishing), after deposition (particles, voids). **Tools**: Optical inspection, e-beam inspection, brightfield/darkfield microscopy. **Applications**: Process monitoring, yield protection, equipment qualification, contamination control. Inline inspection is **early warning system** — catching defects when they occur, not after hundreds of process steps.