ISO 16413:2020

FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 16413
ISO/TC 201
Evaluation of thickness, density
Secretariat: JISC
and interface width of thin films by
Voting begins on:
2020­03­11 X-ray reflectometry — Instrumental
requirements, alignment and
Voting terminates on:
2020­05­06
positioning, data collection, data
analysis and reporting
Évaluation de l'épaisseur, de la densité et de la largeur de l'interface
des films fins par réflectrométrie de rayons X — Exigences
instrumentales, alignement et positionnement, rassemblement des
données, analyse des données et rapport
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ISO/FDIS 16413:2020(E)
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©
NATIONAL REGULATIONS. ISO 2020

ISO/FDIS 16413:2020(E)
© ISO 2020
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ISO/FDIS 16413:2020(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions, symbols and abbreviated terms . 1
3.1 Symbols and abbreviated terms. 3
4 Instrumental requirements, alignment and positioning guidelines .4
4.1 Instrumental requirements for the scanning method . 4
4.1.1 Schematic diagrams . 4
4.1.2 Incident beam — Requirements and recommendations . 5
4.1.3 Specimen — Requirements and recommendations . 7
4.1.4 Goniometer — Requirements . 8
4.1.5 Detector — Requirements . 8
4.2 Instrument alignment . 9
4.3 Specimen alignment . 9
5 Data collection and storage .11
5.1 Preliminary remarks .11
5.2 Data scan parameters .11
5.3 Dynamic range.11
5.4 Step size (peak definition) .12
5.4.1 Fixed intervals scan .12
5.4.2 Continuous scan .12
5.5 Collection time (accumulated counts) .12
5.6 Segmented data collection .12
5.7 Reduction of noise .13
5.8 Detectors .13
5.9 Environment .13
5.10 Data storage .13
5.10.1 Data output format .13
5.10.2 Headers .13
6 Data analysis .14
6.1 Preliminary data treatment .14
6.2 Specimen modelling .14
6.2.1 General.14
6.2.2 Interface width models .15
6.3 Simulation of XRR data .16
6.4 General examples .16
6.5 Data fitting .22
7 Information required when reporting XRR analysis .24
7.1 General .24
7.2 Experimental details .24
7.3 Analysis (simulation and fitting) procedures .25
7.4 Methods for reporting XRR curves .26
7.4.1 Independent and dependent variables .26
7.4.2 Graphical plotting of XRR data .26
Annex A (informative) Example of report for an oxynitrided silicon wafer .29
Bibliography .32
ISO/FDIS 16413:2020(E)
Foreword
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electrotechnical standardization.
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described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
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This document was prepared by Technical Committee ISO/TC 201, Surface chemical analysis.
This second edition cancels and replaces the first edition (ISO 16413:2013), of which it constitutes a
minor revision. The changes compared to the previous edition are as follows:
— editorial changes, mainly for a more precise description, e.g. ‘incidence angle’ has been replaced by
‘grazing incidence angle’, ‘intensity’ has been replaced in the appropriate diagrams by ‘reflectivity’ etc.
Any feedback or questions on this document should be directed to the user’s national standards body. A
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ISO/FDIS 16413:2020(E)
Introduction
X-Ray Reflectometry (XRR) is widely applicable to the measurement of thickness, density and interface
width of single layer and multi-layered thin films which have thicknesses between approximately 1 nm
and 1 μm, on flat substrates, provided that the layer, equipment and X-ray wavelength are appropriate.
Interface width is a general term; it is typically composed of interface or surface roughness and/or
density grading across an interface. The specimen needs to be laterally uniform under the footprint of
the X-ray beam. In contrast with typical surface chemical analysis methods which provide information
of the amount of substance and need conversion to estimate thicknesses, XRR provides thicknesses
directly traceable to the unit of length. XRR is very powerful method to measure the thickness of thin
film with SI traceability.
The key requirements for equipment suitable for collecting specular X-ray reflectivity data of high
quality, and the requirements for specimen alignment and positioning so that useful, accurate
measurements may be obtained are described in Clause 3.
The key issues for data collection to obtain specular X-ray reflectivity data of high quality, suitable
for data treatment and modelling are described in Clause 4. The collection of the data is traditionally
conducted by running single measurements under direct operator data input. However, recently data
are often collected by instructing the instrument to operate in multiple ru
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