IEC 62047-21:2014

IEC 62047-21 ®
Edition 1.0 2014-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Semiconductor devices – Micro-electromechanical devices –
Part 21: Test method for Poisson's ratio of thin film MEMS materials

Dispositifs à semiconducteurs – Dispositifs microélectromécaniques –
Partie 21: Méthode d'essai relative au coefficient de Poisson des matériaux
MEMS en couche mince
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.

Droits de reproduction réservés. Sauf indication contraire, aucune partie de cette publication ne peut être reproduite
ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie
et les microfilms, sans l'accord écrit de l'IEC ou du Comité national de l'IEC du pays du demandeur. Si vous avez des
questions sur le copyright de l'IEC ou si vous désirez obtenir des droits supplémentaires sur cette publication, utilisez
les coordonnées ci-après ou contactez le Comité national de l'IEC de votre pays de résidence.

IEC Central Office Tel.: +41 22 919 02 11
3, rue de Varembé Fax: +41 22 919 03 00
CH-1211 Geneva 20 info@iec.ch
Switzerland www.iec.ch
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigenda or an amendment might have been published.

IEC Catalogue - webstore.iec.ch/catalogue Electropedia - www.electropedia.org
The stand-alone application for consulting the entire The world's leading online dictionary of electronic and
bibliographical information on IEC International Standards, electrical terms containing more than 30 000 terms and
Technical Specifications, Technical Reports and other definitions in English and French, with equivalent terms in 14
documents. Available for PC, Mac OS, Android Tablets and additional languages. Also known as the International
iPad. Electrotechnical Vocabulary (IEV) online.

IEC publications search - www.iec.ch/searchpub IEC Glossary - std.iec.ch/glossary
The advanced search enables to find IEC publications by a More than 55 000 electrotechnical terminology entries in
variety of criteria (reference number, text, technical English and French extracted from the Terms and Definitions
committee,…). It also gives information on projects, replaced clause of IEC publications issued since 2002. Some entries
and withdrawn publications. have been collected from earlier publications of IEC TC 37,

77, 86 and CISPR.
IEC Just Published - webstore.iec.ch/justpublished
Stay up to date on all new IEC publications. Just Published IEC Customer Service Centre - webstore.iec.ch/csc
details all new publications released. Available online and If you wish to give us your feedback on this publication or
also once a month by email. need further assistance, please contact the Customer Service
Centre: csc@iec.ch.
A propos de l'IEC
La Commission Electrotechnique Internationale (IEC) est la première organisation mondiale qui élabore et publie des
Normes internationales pour tout ce qui a trait à l'électricité, à l'électronique et aux technologies apparentées.

A propos des publications IEC
Le contenu technique des publications IEC est constamment revu. Veuillez vous assurer que vous possédez l’édition la
plus récente, un corrigendum ou amendement peut avoir été publié.

Catalogue IEC - webstore.iec.ch/catalogue Electropedia - www.electropedia.org
Application autonome pour consulter tous les renseignements
Le premier dictionnaire en ligne de termes électroniques et
bibliographiques sur les Normes internationales,
électriques. Il contient plus de 30 000 termes et définitions en
Spécifications techniques, Rapports techniques et autres
anglais et en français, ainsi que les termes équivalents dans
documents de l'IEC. Disponible pour PC, Mac OS, tablettes
14 langues additionnelles. Egalement appelé Vocabulaire
Android et iPad.
Electrotechnique International (IEV) en ligne.

Recherche de publications IEC - www.iec.ch/searchpub
Glossaire IEC - std.iec.ch/glossary
La recherche avancée permet de trouver des publications IEC Plus de 55 000 entrées terminologiques électrotechniques, en
en utilisant différents critères (numéro de référence, texte, anglais et en français, extraites des articles Termes et
comité d’études,…). Elle donne aussi des informations sur les Définitions des publications IEC parues depuis 2002. Plus
projets et les publications remplacées ou retirées. certaines entrées antérieures extraites des publications des

CE 37, 77, 86 et CISPR de l'IEC.
IEC Just Published - webstore.iec.ch/justpublished

Service Clients - webstore.iec.ch/csc
Restez informé sur les nouvelles publications IEC. Just
Published détaille les nouvelles publications parues. Si vous désirez nous donner des commentaires sur cette
Disponible en ligne et aussi une fois par mois par email. publication ou si vous avez des questions contactez-nous:
csc@iec.ch.
IEC 62047-21 ®
Edition 1.0 2014-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Semiconductor devices – Micro-electromechanical devices –

Part 21: Test method for Poisson's ratio of thin film MEMS materials

Dispositifs à semiconducteurs – Dispositifs microélectromécaniques –

Partie 21: Méthode d'essai relative au coefficient de Poisson des matériaux

MEMS en couche mince
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX M
ICS 31.080.99 ISBN 978-2-8322-1650-7

– 2 – IEC 62047-21:2014 © IEC 2014
CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references . 5
3 Terms, definitions, symbols and designations . 5
3.1 Terms and definitions. 5
3.2 Symbols and designations . 5
4 Test piece . 6
4.1 General . 6
4.2 Shape of the test piece . 7
4.3 Measurement of dimensions . 7
5 Testing method and test apparatus . 7
5.1 Test principle . 7
5.2 Test machine . 7
5.3 Test procedure. 7
5.3.1 Test procedure for type 1 test piece . 7
5.3.2 Test procedure for type 2 test piece . 8
5.4 Test environment . 8
6 Test report . 8
Annex A (informative) Measurement example of Poisson's ratio using type 1 test piece . 9
A.1 Fabrication of the test piece . 9
A.2 Dimensions of the test piece . 9
A.3 Test procedures . 9
A.4 Test results . 10
Annex B (informative) Analysis of test results obtained from a type 2 test piece . 11
B.1 General . 11
B.2 Evaluation of stress and strain in circular and rectangular membranes . 11
B.3 Evaluation of Poisson’s ratio . 12
Bibliography . 13

Figure 1 – Two types of test pieces for the measurement of Poisson's ratio . 6
Figure A.1 − Optical images of markers for strain measurement by DIC . 9
Figure A.2 – Graphs of load and strain in the longitudinal and transverse directions . 10

Table 1 – Symbols and designations of a test piece . 6

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SEMICONDUCTOR DEVICES –
MICRO-ELECTROMECHANICAL DEVICES –

Part 21: Test method for Poisson's ratio
of thin film MEMS materials
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote
international co-operation on all questions concerning standardization in the electrical and electronic fields. To
this end and in addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 62047-21 has been prepared by subcommittee 47F: Micro-
electromechanical systems, of IEC technical committee 47: Semiconductor devices.
The text of this standard is based on the following documents:
FDIS Report on voting
47F/185/FDIS 47F/189/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

– 4 – IEC 62047-21:2014 © IEC 2014
A list of all parts in the IEC 62047 series, published under the general title Semiconductor
devices – Micro-electromechanical devices, can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct
understanding of its contents. Users should therefore print this document using a
colour printer.
SEMICONDUCTOR DEVICES –
MICRO-ELECTROMECHANICAL DEVICES –

Part 21: Test method for Poisson's ratio
of thin film MEMS materials
1 Scope
This part of IEC 62047 specifies the determination of Poisson's ratio from the test results
obtained by the application of uniaxial and biaxial loads to thin-film micro-electromechanical
systems (MEMS) materials with lengths and widths less than 10 mm and thicknesses less
than 10 µm.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 62047-8:2011, Semiconductor devices – Micro-electromechanical devices – Part 8: Strip
bending test method for tensile property measurement of thin films
ASTM E 132-04:2010, Standard test method for Poisson's ratio at room temperature
3 Terms, definitions, symbols and designations
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1.1
Poisson's ratio
ν
ratio of transverse strain multiplied by (-1) to the corresponding longitudinal strain resulting
from uniformly distributed longitudinal stress below the proportional limit of the material,
ε /ε , where ε is transverse strain, and ε is longitudinal strain
expressed as -
t l t l
3.2 Symbols and designations
Symbols and designations of two types of test pieces are presented in Figure 1 and Table 1,
respectively.
– 6 – IEC 62047-21:2014 © IEC 2014
R
l
L
IEC  1836/14
a) Type 1 test piece for uniaxial tensile machine
m m
2 3
IEC  1837/14
b) Type 2 test piece for membrane bulging machine

Figure 1 – Two types of test pieces for the measurement of Poisson's ratio
Table 1 – Symbols and designations of a test piece
Symbol Unit Designation
l Gauge length for longitudinal strain measurement
µm
l µm Gauge length for transverse strain measurement
b µm Width of test piece
L µm Overall length
R µm Filet radius of test piece
m µm Length of a rectangular membrane
m Width of a rectangular membrane
µm
m Diameter of a circular membrane
µm
h Thickness of membrane
µm
4 Test piece
4.1 General
The test piece should be prepared using a fabrication process similar to the actual fabrication
of devices. It should have dimensions on the same order as those of the mother device to
minimise the effect of size-dependent properties. An example of the fabrication process can
be found in IEC 62047-8. The gradient of the internal stress in the direction of thickness
should be minimised using an annealing process, but the annealing process should be
avoided when Young's modulus and Poisson's ratio of the sample can be affected. Two types
of test pieces are utilised in this standard and are described in the following 4.2 and 4.3.
m
b
l
h
4.2 Shape of the test piece
Two types of test pieces are specified in this standard. Type 1 has a shape similar to a tensile
specimen (Figure 1a), whereas type 2 has two membranes (Figure 1b). In type 1, two pairs of
gauge markers shall be fashioned to define both longitudinal and transverse strains. By
measuring the longitudinal and transverse strains, the Poisson’s ratio is calculated by the
ratio of -ε /ε specified in 3.1. When a wrinkle forms in the test piece during the tensile test
t l
due to compressive strain in the transverse direction, undesirable out-of-plane deformation
can lead to an error in the optical measurement, obscuring the optical measurement of
transverse strain. In this case, a type 2 test piece should be used instead of a type 1 test
piece. In type 2, circular and rectangular membranes are included in the test piece. The
maximum deflections of the two membranes are measured simultaneously under a given
pressure. The pressure applied to the two membranes should be identical. The out-of-plane
deflection due to the applied pressure should be measured using an optical technique or
atomic force microscopy (AFM) to minimise the mechanical disturbance of the test piece. For
/ m ) should be larger
the rectangular membrane, the ratio between the length and width (m
1 2
than 4.
4.3 Measurement of dimensions
To analyse the test results, an accurate measurement of the test-piece dimensions is required
because the dimensions are used to extract the mechanical properties of test materials. In the
type 1 test piece, the longitudinal and transverse gauge lengths (l l ), width (b), and
1, 2
thickness (h) shall be measured with an error of less than ± 5 %. In the type 2 test piece, the
width (m ) of the rectangular membrane, the diameter (m ) of the circular membrane, and the
2 3
film thickness (h) shall be measured with an error of less than ± 5 %.
5 Testing method and test apparatus
5.1 Test principle
With a type 1 test piece, the test is performed by applying a tensile load to the test piece. The
longitudinal and transverse strains induced by the tensile load should be uniform over a pre-
defined gauge section in the elastic region of the test piece. The longitudinal and transverse
strains should be measured simultaneously, and the time delay between them should be less
than 1/100 of the data-sampling period. When there is curling in the test piece, it is difficult to
measure the transverse strain. In this case, Poisson's ratio should be measured using a
type 2 test piece. With a type 2 test piece, the test is performed by applying air pressure to
the test piece. The circular and rectangular membranes should experience the same applied
pressure. The deflections of both membranes should be measured simultaneously, and the
time delay between them should be less than 1/100 of the data-sampling period.
5.2 Test machine
The test machine for a type 1 test piece is similar to a conventional tensile test machine,
except that it is capable of measuring transverse strain. Due to the thinness of the test piece,
the longitudinal and transverse strains shall be measured using optical techniques such as
laser interferometry or digital image correlation (DIC). The test machine for a type 2 test piece
consists of an air compressor, air regulator, pressure sensor, and displacement sensor for
measuring out-of-plane deflections.
5.3 Test procedure
5.3.1 Test procedure for type 1 test piece
a) Fix the test piece using the tensile grip. The longitudinal direction of the test piece shall
be aligned with the actuating direction of the test apparatus, and the deviation angle shall
be less than 1 degree, as specified in 4.4 of IEC 62047-8:2011.
b) Verify the strain measurement unit for longitudinal and transverse strains. These strain
signals shall be measured simultaneously with the load signal.

– 8 – IEC 62047-21:2014 © IEC 2014
c) Apply a tensile load to the test piece at a constant strain rate (or grip-to-grip displacement
-1 -1
rate). The strain rate shall range from 0,01 min to 10 min depending on the material
system of the test piece and the actual usage condition of the customer.
d) Unload the test apparatus when the load sufficiently exceeds the proportional limit.
e) Draw a graph of the longitudinal and transverse strains with respect to load as described
in ASTM E 132-04 and determine Poisson's ratio.
5.3.2 Test procedure for type 2 test piece
a) Fix the test piece to the grip of the test apparatus. The grip should have inlet and outlet
ports for air pressure and a connection port that allows air pressure to be applied to the
test piece. The air pressure line in the grip should be designed to deliver identical
pressure to both membranes in the test piece.
b) Apply air pressure to both the circular and rectangular membranes in the test piece and
measure the central deflections of both membranes and the applied pressure.
c) Unload the test apparatus when the pressure exceeds the proportional limit of the test
piece or if the membranes rupture.
d) Analyse the test results and determine Poisson's ratio according to Annex B.
5.4 Test environment
Because the mechanical properties are temperature and humidity sensitive, fluctuations in
temperature during the test shall be controlled to be less than ± 2 °C, and the change in
relative humidity (RH) in the testing laboratory shall be controlled to be less than ± 5 % RH.
6 Test report
The test report shall contain the following information.
a) Reference to this international standard;
b) Test piece identification;
c) Test piece material;
– using a single crystal: crystallographic orientation;
– using a poly-crystal: texture and grain size;
d) Shape and dimensions of the test piece;
e) Test piece fabrication method details:
– deposition method;
– annealing conditions;
– fabrication conditions;
f) Testing system:
– testing apparatus;
– load and strain measurement method (or pressure and deflection);
g) Measured properties and results: Poisson's ratio, longitudinal and transverse strains
versus applied load (or pressure) curve.

Annex A
(informative)
Measurement example of Poisson's ratio using type 1 test piece

A.1 Fabrication of the test piece
The test piece for measurement of Poisson's ratio is fabricated by MEMS processes. Similar
fabrication processes can be found in Annex B of IEC 62047-8:2011.
A.2 Dimensions of the test piece
The test pieces should be fabricated with a length of 2 mm, a width of 500 µm, and a filet
radius of 5 mm (Figure 1). To analyse the test data, dimensions of the test pieces should be
measured accurately. The thickness of the test piece is measured to be 2,8 µm using a
scanning electron microscope. As shown in Figure A.1, longitudinal and transverse strains are
measured after the markers for strain measurement are defined.
A.3 Test procedures
Tests are performed using a micro-tensile testing apparatus. After the test piece is fixed on
jigs, uni-axial tensile force is applied in the longitudinal direction of the test piece using a
piezoelectric actuator. The longitudinal direction coincides with the <110> direction of the test
−4
piece made of single-crystal silicon. The strain rate is 5 × 10 /s during the test. Longitudinal
and transverse strains are measured using DIC with the images acquired from a microscope.
Markers for DIC are shown in Figure A.1. Larger spacing between the two markers of the
longitudinal direction leads to higher resolution of the strain measurement for a given optical
system. In this test, the longitudinal and transverse gauge lengths are 250 µm and 173 µm,
which are taken from the field of view of the optical system and maximum displacement of the
test piece. Both longitudinal and transverse strains (ε , ε) and load (F) are acquired
l t
simultaneously by a data-acquisition module.
Marker of longitudinal direction
Marker of transverse direction

173 µm
Tensile
Tensile
250 µm
direction
direction
<110>
<110>
IEC  1838/14 IEC  1839/14
a) Markers for longitudinal strain b) Markers for transverse strain
Figure A.1 − Optical images of markers for strain measurement by DIC

– 10 – IEC 62047-21:2014 © IEC 2014
A.4 Test results
From the measured data, a F–ε curve can be obtained (Figure A.2). After fitting the two
curves linearly, the slopes of the two curves are obtained as dε /dF = 0,004 43 and
l
dε /dF =−0,001 13. Then, Poisson's ratio is calculated by
t
dε dF
t
υ = − = 0,267. (A.1)
dε dF
l
0,0030
0,003 0
longitiudinal strain, ε
longitudinal strain,l ε
l
0,0,0000252 5
transverse strain, ε
transverse strain, ε
t
t
0,002 0
0,0020 slope, ε = −0,004 43
l
slope, ε = 0,00443
l
slope, ε = −0,001 13
t
slope, ε = -0,00113
0,0015
0,001 5 t
0,0010
0,001 0
0,0,0000500 5
0,0,0000000 0
-−00,,0000050 5
-0,0010
−0,001 0
-−00,,0001 5015
0 0,2 0,4 0,6
0,0 0,2 0,4 0,6
Load,  N
Load (N)
IEC  1840/14
Figure A.2 – Graphs of load and strain in the longitudinal and transverse directions

Engineering Strain,  ε
Engineering Strain (ε)
Annex B
(informative)
Analysis of test results obtained from a type 2 test piece

B.1 General
The type 2 test piece membranes are isotropic and homogeneous. Bending stiffness of the
membranes is assumed to be negligible, and this is acceptable for membranes for which the
thickness is much less than the width and the diameter. The ratio between the length and the
width of the rectangular membrane should be greater than 4.
B.2 Evaluation of stress and strain in circular and rectangular membranes
When air pressure (p) is applied to the two membrane types, circular and rectangular, the
membranes are strained, and the corresponding stress builds up. For the circular membrane
with a diameter D, a thickness h, and a central deflection δ , the equi-biaxial stress
circular
(σ ) and strain (ε ) in the membrane are evaluated using the following equations
circular circular
according to [1] :
pD
σ =
circular
(B.1)
16hδ
circular
2δ
circular
(B.2)
ε =
circular
D
The stress and strain are related by the following equation:
E
σ = ε
. (B.3)
circular circular
1−ν
Here, E is Young’s modulus, and ν is Poisson’s ratio. For the rectangular membrane with a
width W, a thickness h,
...