Reflectometry / Scatterometry
CXRO operates EUV and soft X-ray reflectometer beamlines at the Advanced Light Source that serve as a worldwide reference standard for reflectivity, transmittance, and optical constant measurements. Mirrors and detectors are the foundation of soft X-ray science — the CXRO reflectometer routinely measures the reflectivity and scattering properties of the most advanced X-ray and EUV optics in the world. These measurements are essential for the design and qualification of optics for EUV lithography, synchrotron instrumentation, and space-based telescopes.
Beamline Specifications
| Energy Range | 50–1500 eV (EUV through soft X-ray) |
| Angular Range | 0–90° grazing incidence; normal incidence |
| Reflectivity Accuracy | ±0.1% absolute |
| Sample Size | Up to 200 mm substrates |
| Measurement Types | Specular reflectivity, transmittance, rocking curves, diffuse scatter, s- and p-polarization |
| Beamlines | ALS 6.3.2 (reflectometry), ALS 11.0.2 |
| Wavelength Precision | 0.007% |
| Spectral Purity | 99.98% |
| Dynamic Range | 10¹⁰ |
| Beam Size | 10 μm × 300 μm |
| Positioning Precision | 10 μm spatial; 0.01° angular |
| Degrees of Freedom | 6 |
Applications
Multilayer Mirror Qualification
Measure peak reflectivity, center wavelength, bandwidth, and uniformity of Mo/Si and other multilayer coatings for EUV lithography optics.
Optical Constant Determination
Extract complex refractive indices (n, k) from reflectivity and transmittance measurements to update the CXRO database and support optical design.
Thin-Film Metrology
Determine thickness, density, and interface roughness of single layers and multilayer stacks from model fitting of reflectivity curves.
Filter & Optics Characterization
Measure transmission of thin-film filters, gratings, and other optical elements used in beamlines, spectrometers, and space instruments.
Related Research
Reflectometry supports Novel Materials and Microelectronics research.
