Overview
ISO 23729:2022 - "Surface chemical analysis - Atomic force microscopy - Guideline for restoration procedure for atomic force microscopy images dilated by finite probe size" - specifies a quantitative procedure to characterize AFM probe tips and restore AFM topography images that are distorted by the finite size and shape of the probe apex. The standard describes extracting a three‑dimensional probe apex shape (probe shape function, PSF) from scans of certified probe characterizers and applying mathematical‑morphology operations (dilation/erosion) to reconstruct true surface topography of solid material surfaces.
Key topics and technical requirements
- Scope and purpose: Guidance for quantitative restoration of AFM height/topography images dilated by probe geometry; applicable to solid surfaces.
- Mathematical morphology modelling: Uses dilation (I = S ⊕ P) to describe image formation and erosion (S = I ⊖ P) for image reconstruction; addresses non‑reconstructable (hole) regions caused by finite tip size.
- Probe characterization:
- Extraction of reflected‑tip shape (P) from scans of certified reference materials (probe characterizers) using erosion-based reconstruction.
- Blind reconstruction methods for estimating probe shape when reference data are unavailable.
- Definitions of probe shape characteristic (PSC) and probe radius (R); probe shape function (PSF).
- Calibration and metrology:
- Calibration of X/Y/Z piezo scanners, deflection sensitivity, and cantilever normal spring constants per referenced standards.
- Normative references include ISO 11775, ISO 11952, and ISO 18115‑2.
- Measurement environment: Recommendations for temperature stability (±1 °C or better), drift assessment, and measurement intervals.
- Validation: Procedures for validity testing of restored topography; annexes provide example studies and interlaboratory comparison results.
Practical applications and users
ISO 23729:2022 is intended for:
- AFM operators, instrument manufacturers, and metrology laboratories performing nanoscale surface characterization.
- Researchers in materials science, semiconductor critical dimension (CD) analysis, nanotechnology, and surface chemical analysis who require reproducible, quantitative 3D topography.
- Quality control and R&D teams seeking standardized procedures for probe‑shape artefact correction, improved accuracy in AFM measurements, and traceability when using reference materials (e.g., nanosphere standards).
Related standards
- ISO 11775 - cantilever spring constant determination
- ISO 11952 - calibration of SPM measuring systems (geometric quantities)
- ISO 18115‑2 - SPM terminology
Keywords: ISO 23729:2022, AFM, atomic force microscopy, probe tip characterization, probe shape function, image restoration, dilation, erosion, mathematical morphology, probe characterizer, topography reconstruction.