SIST EN ISO 23131:2023

SLOVENSKI STANDARD
SIST EN ISO 23131:2023
01-januar-2023
Elipsometrija - Načela (ISO 23131:2021)
Ellipsometry - Principles (ISO 23131:2021)
Ellipsometrie - Grundlagen (ISO 23131:2021)
Ellipsométrie - Principes (ISO 23131:2021)
Ta slovenski standard je istoveten z: EN ISO 23131:2022
ICS:
17.020 Meroslovje in merjenje na Metrology and measurement
splošno in general
SIST EN ISO 23131:2023 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 23131:2023

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SIST EN ISO 23131:2023


EN ISO 23131
EUROPEAN STANDARD

NORME EUROPÉENNE

November 2022
EUROPÄISCHE NORM
ICS 17.020
English Version

Ellipsometry - Principles (ISO 23131:2021)
Ellipsométrie - Principes (ISO 23131:2021) Ellipsometrie - Grundlagen (ISO 23131:2021)
This European Standard was approved by CEN on 30 October 2022.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.





EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2022 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 23131:2022 E
worldwide for CEN national Members.

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SIST EN ISO 23131:2023
EN ISO 23131:2022 (E)
Contents Page
European foreword . 3

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SIST EN ISO 23131:2023
EN ISO 23131:2022 (E)
European foreword
The text of ISO 23131:2021 has been prepared by Technical Committee ISO/TC 107 "Metallic and other
inorganic coatings” of the International Organization for Standardization (ISO) and has been taken over
as EN ISO 23131:2022 by Technical Committee CEN/TC 262 “Metallic and other inorganic coatings,
including for corrosion protection and corrosion testing of metals and alloys” the secretariat of which is
held by BSI.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by May 2023, and conflicting national standards shall be
withdrawn at the latest by May 2023.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 23131:2021 has been approved by CEN as EN ISO 23131:2022 without any modification.


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SIST EN ISO 23131:2023

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SIST EN ISO 23131:2023
INTERNATIONAL ISO
STANDARD 23131
First edition
2021-04
Ellipsometry — Principles
Ellipsométrie — Principes
Reference number
ISO 23131:2021(E)
©
ISO 2021

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SIST EN ISO 23131:2023
ISO 23131:2021(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2021
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved

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SIST EN ISO 23131:2023
ISO 23131:2021(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions, symbols and abbreviated terms . 1
3.1 Terms and definitions . 1
3.2 Symbols and abbreviated terms. 1
4 Experimental boundary conditions with respect to the sample . 2
5 Experimental boundary conditions with respect to the measurement .3
6 Model-correlated boundary conditions of the simulation. 4
7 Basic models . 4
7.1 General . 4
7.2 Bulk material (case 1 of application) . 5
7.3 Transparent single layer (case 2 of application) . 5
7.4 Semi-transparent single layer (case 3 of application) . 5
7.5 Multiple layers and periodic layers (case 4 of application) . 5
7.6 Effective materials (case 5 of application) . 5
8 Raw data . 5
9 Verification of correct adjustment of the device . 5
9.1 Straight line measurement . 5
9.2 Simple measurement of angles . 6
9.2.1 Measurement on a known sample, e.g. SiO /Si, with fitting of the angle of
2
incidence . 6
9.2.2 Measurement of the Brewster’s angle of water, of a solvent or of technical glass . 8
10 Verification of the device regarding correct calibration . 9
11 Test report . 9
Annex A (informative) Mathematical and physical principles of ellipsometry.10
Bibliography .15
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SIST EN ISO 23131:2023
ISO 23131:2021(E)

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
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
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO’s adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 107, Metallic and other inorganic coatings.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2021 – All rights reserved

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SIST EN ISO 23131:2023
ISO 23131:2021(E)

Introduction
The ellipsometry measuring method is a phase-sensitive reflection technique using polarized light in
the optical far-field. Over a long time, ellipsometry has been established as a non-invasive measuring
method in the field of semiconductor technology — especially within the integrated production — in
the first instance as a single-wavelength, then as a multiple-wavelength and later as a spectroscopic
measuring method.
By means of ellipsometry, optical or dielectric constants of any material as well as the layer thicknesses
of at least semi-transparent layers or layer systems can be determined. Ellipsometry is an indirect
measuring method, the analysis of which is based on model optimization. The measurands, which differ
according to the procedural principle, are converted into the ellipsometric factors Ψ (Psi, amplitude
information) and Δ (Delta, phase information), based on which the physical target figures of interest
(optical or dielectric constants, layer thicknesses) will then be determined by means of a parameterized
fit.
Ellipsometry shows a high precision regarding the ellipsometric transfer quantities Ψ and Δ, which can
be equivalent to a layer thickness sensitivity of 0,1 nm for ideal layer substrate systems. As a result,
the measuring method can verify even the slightest discrepancies in the surface characteristics.
This is closely linked to the homogeneity and the isotropy of the material surface. In order to achieve
high precision, carrying out measurements at the exact same measuring point is a prerequisite for
inhomogeneous materials. The same applies to the orientation of the incident plane relative to the
material surface for anisotropic materials.
The absolute accuracy, e.g. of layer thickness values, substantially depends on the quality of the
chosen model for describing the material surface. For ideal layer substrate systems, such as SiO (ideal
2
transparent layer) on a Si wafer (nearly atomically smooth substrate surface with homogeneous and
isotropic material properties), the accuracy of the layer thickness can indeed reach the precision
values, since the model describes the reality of the layer substrate system in an ideal manner. For
inhomogeneous, anisotropic, contaminated, multi-component, damaged, imperfect or rough surfaces
or layers, the accuracy of the layer thickness determination can be significantly lower and generally
depends on the quality of the chosen model.
Despite these limitations, ellipsometry is a powerful procedure, which either enables material
fingerprints (without modelling) or which allows a model-based determination of optical and dielectric
constants (to the nearest 0,001) or of layer thicknesses (to the nearest 0,1 nm) within a broad layer
thickness range of approximately 0,1 nm up to approximately 10 µm (in special cases exceeding
100 µm).
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SIST EN ISO 23131:2023
INTERNATIONAL STANDARD ISO 23131:2021(E)
Ellipsometry — Principles
1 Scope
This document specifies a method for determining optical and dielectric constants in the UV-VIS-NIR
spectral range as well as layer thicknesses in the field of at-line production control, quality assurance
and material development through accredited test laboratories.
It is applicable to stand-alone measuring systems. The presentation of the uncertainty of results
conforms to ISO/IEC Guide 98-3.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
ISO/IEC Guide 98-3, Uncertainty of measurement — Part 3: Guide to the expression of uncertainty in
me a s ur ement (GUM: 1995)
3 Terms, definitions, symbols and abbreviated terms
3.1 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.2 Symbols and abbreviated terms
Symbol or
Description
abbreviated term
P polarizer
C compensator
S sample
A analyzer
POI plane of incidence of light, formed by the normal to the surface and the direction
of propagation of the incident light
POP plane of polarization of light, formed by the electric field vector and the direction
of propagation of the incident light
Ψ, Δ ellipsometric transfer quantities Psi and Delta, which serve as raw data to be stored,
e.g. in accordance with ISO/IEC 17025
φ angle of incidence between the incident light wave and the axis of incidence
d layer thickness
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SIST EN ISO 23131:2023
ISO 23131:2021(E)

4 Experimental boundary conditions with respect to the sample
Figures 1 and 2 schematically represent an ellipsometric measurement as a phase-sensitive reflection
technique using polarized light; both under photo-optical aspects (see Figure 1) as well as under
metrological aspects (see Figure 2).
Key
1 sample
2 POI
φ angle of incidence
Figure 1 — Schematic representation of the optical path/polarization state before and after
reflection (substrate surface, axis and angle of incidence, optical path/light wave, s- and
p-polarization)
Key
1 polarizer
2 compensator
3 sample
4 analyser
5 detector
6 light source
Figure 2 — Schematic representation of the metrological arrangement
(light source, P-C-S-A configuration)
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SIST EN ISO 23131:2023
ISO 23131:2021(E)

The following experimental boundary conditions with respect to the sample should be agreed upon in
advance and, if relevant, be documented in the test report:
— determine/specify the measuring point (evaluation of homogeneity) and the sample orientation
(evaluation of isotropy);
— surface condition: take a micrograph of the surface if necessary;
— surface topography: if necessary, measure the surface roughness;
— further sample properties to be considered or corrected:
— curved and wedged samples;
— influence of backside reflection (for transparent samples), if present;
— surface as-delivered or cleaned;
— fixation of the sample.
5 Experimental boundary conditions with respect to the measurement
The following experimental boundary conditions with respect to the measurement should be agreed
upon in advance and, if relevant, be documented in the test report:
— indication of whether an imaging ellipsometer or a mapping ellipsometer (manual or automatic) is
concerned;
— for imaging ellipsometers the following factors are relevant: resulting size of the measuring field/
of the region of integration [FOI (field of illumination: sample surface that is illuminated by the
incident light), FOV (field of view: sample surface within the FOI from which the light collected by
the detector originates), ROI (region of interest: sample surface within the FOV that is relevant for
the measurement)];
— for mapping ellipsometers the following factors are relevant: resulting size of the measuring field/
of the region of integration [FOI (field of illumination: sample surface that is illuminated by the
incident light), FOA (field of analysis: sample surface within the FOI from which the light collected
by the detector originates)];
— ellipsometer configurations: [P-S-A, P-C-S-A, P-S-C-A or P-C-S-C-A];
— ellipsometer principle [RAE (rotating analyser ellipsometer), RPE (rotating polarizer ellipsometer),
PME (phase modulated ellipsometer), RCE (rotating compensator ellipsometer), NE (nulling
ellipsometer), SSE (step scan ellipsom
...