ISO 16413:2020

Overview

ISO 16413:2020 specifies a standardized method for evaluating thickness, density and interface width of single- and multi-layer thin films (approx. 1 nm to 1 µm) on flat substrates using X‑ray reflectometry (XRR). The standard covers instrumental requirements, alignment and positioning, data collection and storage, data analysis (modelling, simulation and fitting) and reporting of results. It applies to laboratory instruments, synchrotron beamline reflectometers and automated industrial systems using a monochromatic, collimated X‑ray beam with angular or scattering‑vector scans. Proprietary techniques and diffuse XRR are not described.

Key technical topics and requirements

• Instrumental requirements: guidance on incident beam characteristics, specimen handling, goniometer performance and detector considerations to obtain high‑quality specular XRR data.
• Alignment and positioning: procedures for instrument and specimen alignment to ensure reliable footprint, grazing incidence angles and reproducible geometry.
• Data collection parameters: recommended approaches for scan types (fixed‑interval vs continuous), step size, dynamic range, collection time (accumulated counts), segmented collection strategies and noise reduction.
• Data storage and metadata: prescriptions for data output formats and header information needed for later analysis and traceability.
• Data analysis and modelling: principles for preliminary data treatment, specimen modelling (including interface width models, which account for roughness and density grading), simulation of XRR curves and fitting strategies to extract thickness and density.
• Reporting: mandatory experimental details and analysis procedures to include in reports so results are reproducible and SI‑traceable.
• Important caveats: XRR at a single wavelength gives no chemical information - surface contamination or reactions can affect accuracy, especially for the outermost layer; layer instability during long scans reduces measurement accuracy.

Practical applications

• Thin‑film metrology for semiconductors, optics, coatings, and thin‑film research.
• Quality control and process monitoring in manufacturing (thickness & density verification).
• Characterization of multilayer stacks, oxide/nitride films, and thin‑film interfaces.
• Reference measurement methods where SI traceability of thickness is required.

Who should use this standard

• Surface and thin‑film analysts, metrologists and laboratory managers.
• Synchrotron beamline scientists and instrument manufacturers.
• QA/QC engineers in semiconductor, coatings and materials industries.
• Developers of XRR data‑analysis software who need to align output and reporting with international practice.

Practical considerations & related information

• The document emphasizes instrument stability, specimen uniformity under the beam footprint and careful reporting to ensure reproducible, traceable results.
• Prepared by ISO/TC 201 (Surface chemical analysis); this second edition (2020) updates and clarifies the 2013 edition. Proprietary algorithms are intentionally excluded. Keywords: ISO 16413, X‑ray reflectometry, XRR, thin film thickness measurement, density measurement, interface width, metrology, reflectometer.