X-ray Scatterometry is a metrology technique that uses X-ray diffraction/scattering to measure the dimensions of nanoscale semiconductor structures — X-rays' short wavelength (0.1-10 nm) provides sensitivity to sub-nanometer structural details that optical wavelengths cannot resolve.

X-ray Scatterometry Methods

• CDSAXS: Critical Dimension Small-Angle X-ray Scattering — measures CD, pitch, height, and profile from small-angle diffraction.
• XRR: X-ray Reflectometry — measures film thickness and density from interference fringes.
• GISAXS: Grazing Incidence Small-Angle X-ray Scattering — surface and near-surface nanostructure characterization.
• Sources: Lab sources (rotating anode, liquid metal jet) or synchrotron radiation.

Why It Matters

• No Model Ambiguity: X-ray results are less model-dependent than optical OCD — more robust parameter extraction.
• Sub-Nanometer Sensitivity: X-ray wavelengths probe atomic-scale features — essential for <3nm nodes.
• Buried Structures: X-rays penetrate multiple layers — measure buried structures that optical methods cannot see.

X-ray Scatterometry is seeing with atomic resolution — using X-ray scattering for model-robust measurement of the smallest semiconductor features.