Metrology and analysis

What is the technique called that uses statistical models to predict film thickness or dimensions of wafers that were not actually measured, from equipment sensor data and the like?

  1. ADestructive analysis
  2. BVisual inspection
  3. CVirtual metrology
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Answer: C. Virtual metrology

Virtual metrology models the relationship between a tool's sensor data during processing (temperature, pressure, power and so on) and past measurement results, using machine learning or similar, to predict results for unmeasured wafers. It estimates the process state without measuring every wafer, helping with early anomaly detection and control.

  • A. Destructive analysis examines samples by breaking them.
  • B. Visual inspection looks for abnormalities in appearance.
  • C. Correct. It predicts measurements from sensor data.
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