ISO 23729:2022

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.