x-ray fluorescence mapping

**XRF Mapping** (X-Ray Fluorescence Mapping) is a **technique that maps elemental composition across a surface by detecting characteristic X-rays emitted when the sample is excited by an X-ray beam** — providing rapid, non-destructive elemental analysis at ppm sensitivity. **How Does XRF Mapping Work?** - **Excitation**: X-ray beam (from tube or synchrotron) ejects core electrons from sample atoms. - **Fluorescence**: Core hole relaxation produces characteristic X-rays with energies unique to each element. - **Detection**: Energy-dispersive detector measures the X-ray spectrum at each point. - **Mapping**: Scan the beam across the sample to create elemental distribution maps. **Why It Matters** - **Film Thickness**: XRF intensity is proportional to film thickness for thin films — used for thickness monitoring. - **Contamination**: Detects metallic contamination on wafer surfaces (Fe, Cu, Ni, Cr at $10^{10}$-$10^{11}$ atoms/cm²). - **Non-Destructive**: Completely non-contact and non-destructive — suitable for 100% production inspection. **XRF Mapping** is **elemental fingerprinting across the wafer** — using characteristic X-rays to map composition and detect contamination.