hybrid metrology

**Hybrid Metrology** is a **strategy that combines measurements from multiple metrology tools to achieve better accuracy than any single technique** — using statistical methods (Bayesian inference, regression) to fuse data from OCD, CD-SEM, AFM, and TEM into a single, improved measurement result. **How Does Hybrid Metrology Work?** - **Multiple Tools**: Measure the same parameter (e.g., CD) with several techniques (OCD, CD-SEM, AFM). - **Cross-Calibration**: Establish relationships between tool outputs (bias corrections, scaling factors). - **Fusion**: Combine measurements using weighted averaging, Bayesian estimation, or regression models. - **Result**: A single "hybrid" measurement with lower uncertainty than any individual tool. **Why It Matters** - **Accuracy**: Each tool has different systematic errors — combination reduces total measurement uncertainty. - **Reference Metrology**: Hybrid values serve as more accurate reference values for tool matching. - **Industry Push**: SEMI and NIST actively promote hybrid metrology for sub-nm node requirements. **Hybrid Metrology** is **the wisdom of many tools** — combining multiple measurement techniques for dimensional accuracy beyond any single instrument's capability.