IEC TS 62607-6-26:2025

IEC TS 62607-6-26 ®
Edition 1.0 2025-12
TECHNICAL
SPECIFICATION
Nanomanufacturing - Key control characteristics -
Part 6-26: Graphene-related products - Fracture strain and stress, Young’s
modulus, residual strain and residual stress: bulge test
ICS 07.120  ISBN 978-2-8327-0910-8

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CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 7
3.1 General terms . 7
3.2 Mechanical properties related terms . 8
3.3 Key control characteristics measured according to this standard . 8
3.4 Terms related to the measurement method . 9
4 General . 9
4.1 Measurement principle . 9
4.1.1 Measurement principle of a single kind of material layer . 9
4.1.2 Measurement principle of composite layer by two kinds of material . 10
4.2 Sample preparation method . 11
4.2.1 General. 11
4.2.2 Graphene . 11
4.2.3 Nanometre-thick film deposited on Si wafer . 13
4.2.4 Nanometre-thick film deposited on Cu or Ni foil . 14
4.3 Measurement system . 16
4.4 Description of measurement equipment and apparatus . 18
4.5 Supporting materials . 18
5 Measurement procedure . 18
5.1 Calibration of measurement equipment . 18
5.2 Detailed protocol of the measurement procedure . 18
6 Results to be reported . 18
6.1 General . 18
6.2 Product or sample identification . 18
6.3 Test conditions . 19
6.4 Test results . 19
Annex A (informative) Format of the test report. 20
Annex B (informative) Effect of sample geometry on stress–strain relation for three
typical geometries. 22
Annex C (informative) Worked examples . 23
C.1 Graphene bulge test . 23
C.2 Si N and SiN /SiO film bulge test . 23
3 4 x 2
Bibliography . 26

Figure 1 – Applications of mechanical properties to electrical devices . 5
Figure 2 – Various measurement methods to evaluate mechanical properties of 2D and
thin films. 6
Figure 3 – Schematic view of the central section of sample during bulge testing . 10
Figure 4 – Determination of the plane-strain modulus, the residual stress (σ ) and
residual strain (ε ) from the experimental stress–strain curve . 10
Figure 5 – Schematic view of the central section of a composite sample during bulge
testing: a long rectangular membrane . 10
Figure 6 – Typical steps for the preparation of a freestanding graphene (or 2D
material) sample with polycarbonate (PC) supporting layer . 12
Figure 7 – Typical PC/graphene samples: (a), (b) PC/graphene on SiO wafer from
separate experimental runs; (c), (d) PC/graphene freestanding samples from separate
experimental runs . 12
Figure 8 – Typical steps for the preparation of a freestanding metal sample using
Si wafer . 14
Figure 9 – Typical steps for the preparation of a freestanding nanometre-thick film of
graphite on metal foil substrate . 15
Figure 10 – Typical freestanding samples after sample preparation process . 16
Figure 11 – Measurement system consisting of bulge test chamber, pressure sensor,
auto-focus light source for measuring deflection of film, high-speed camera and mass
flow controller . 17
Figure B.1 – Overview of three different geometries . 22
Figure C.1 – Stress–strain curve from bulge test for graphene and PC/graphene . 23
Figure C.2 – Bulge tests comprising both loading and unloading . 24
Figure C.3 – Stress–strain curve from bulge test for SiN of 50 nm . 24
x
Figure C.4 – Stress–strain curve from bulge test for graphite film of 50 nm . 25
Figure C.5 – Stress–strain curve from bulge test for graphite film of 50 nm synthesized
on Ni/Si wafer . 25

Table A.1 – Product identification (in accordance with the relevant blank detail
specification) . 20
Table A.2 – General material description . 20
Table A.3 – Measurement condition. 21
Table A.4 – Test result . 21

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
Nanomanufacturing - Key control characteristics -
Part 6-26: Graphene-related products - Fracture strain and stress,
Young's modulus, residual strain and residual stress: bulge test

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
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9) IEC draws attention to the possibility that the implementation of this document may involve the use of (a)
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shall not be held responsible for identifying any or all such patent rights.
IEC TS 62607-6-26 has been prepared by IEC technical committee 113: Nanotechnology for
electrotechnical products and systems. It is a Technical Specification.
The text of this Technical Specification is based on the following documents:
Draft Report on voting
113/924/DTS 113/939/RVDTS
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this Technical Specification is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
A list of all parts of the IEC TS 62607 series, published under the general title
Nanomanufacturing - Key control characteristics, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
– reconfirmed,
– withdrawn, or
– revised.
INTRODUCTION
When the characteristic dimensions of materials are reduced to the nanoscale regime, their
mechanical properties exhibit significant changes compared to their bulk counterparts. These
changes include enhancements in elasticity, residual strain, and fracture resistance, which are
critical for reliable and high-performance nanoscale devices. Low-dimensional materials, such
as graphene and nanometre-thick films, have gained widespread attention because of their
exceptional thermal, optical, electrical, and mechanical properties. These unique characteristics
make them indispensable in the development of advanced nanoscale technologies.
The mechanical properties of two-dimensional (2D) materials, such as Young's modulus (or
elastic modulus), residual strain, residual stress, and fracture stress, are essential for their
integration into diverse applications. As shown in Figure 1, these properties are utilized in
several applications. These include
a) strain sensors for precise mechanical deformation detection,
b) energy harvesting devices using piezoelectric effects to convert mechanical to electrical
energy,
c) vibrational acoustic applications supporting sound generation or absorption, and
d) pellicle membranes for EUV lithography that maintain structural stability under high thermal
and mechanical stresses during device operation [1] , [2], [3], [4], [5].
These applications highlight the versatility of mechanical properties in enabling innovative
engineering solutions at the nanoscale.

Figure 1 – Applications of mechanical properties to electrical devices
___________
Numbers in square brackets refer to the Bibliography.
Figure 2 – Various measurement methods to evaluate mechanical properties
of 2D and thin films
Accurate characterization of the mechanical properties of 2D materials and thin films is
essential for their effective use in applications. However, conventional methods face significant
challenges. For example, (i) substrate interference often affects techniques like nano-
indentation or wafer curvature, making it difficult to isolate the intrinsic material properties, and
(ii) sample preparation complexity limits the applicability of methods such as micro-tensile tests
and microbeam bending. To overcome these limitations, it is important to adopt methods
designed specifically for freestanding films, which can provide more accurate and reproducible
results.
Figure 2 presents the various techniques used for evaluating the mechanical properties of 2D
materials and thin films. These techniques include
– nano-indentation, suitable for localized measurements but limited by its focus area,
– wafer curvature, effective for measuring residual stress but influenced by the substrate,
– microbeam bending and micro-tensile tests, useful in specific cases but requiring labour-
intensive preparation, and
– bulge test, a reliable method for freestanding films, which measures Young's modulus (or
elastic modulus), residual strain, residual stress, and fracture stress under well-controlled
conditions.
Among these, the bulge test stands out for its practicality and scalability, enabling the
characterization of large areas of freestanding films without substrate interference.

1 Scope
This part of IEC TS 62607 establishes a standardized method to determine the mechanical key
control characteristics (KCCs)
– Young's modulus (or elastic modulus),
– residual strain,
– residual stress, and
– fracture stress
of 2D materials and nanoscale films using the
– bulge test.
The bulge test is a reliable method where a pressure differential is applied to a freestanding
film, and the resulting deformation is measured to derive the mechanical properties.
– This method is applicable to a wide range of freestanding 2D materials, such as graphene,
and nanometre-thick films with thicknesses typically ranging from 1 nm to several hundred
nanometres.
– This document ensures the characterization of mechanical properties essential for
assessing the structural integrity and performance of materials in applications such as
composite additives, flexible electronics, and energy harvesting devices.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following
addresses:
– IEC Electropedia: available at https://www.electropedia.org/
– ISO Online browsing platform: available at https://www.iso.org/obp
3.1 General terms
3.1.1
key control characteristic
KCC
key performance indicator
material property or intermediate product characteristic which can affect safety or compliance
with regulations, fit, function, performance, quality, reliability or subsequent processing of the
final product
Note 1 to entry: The measurement of a key control characteristic is described in a standardized measurement
procedure with known accuracy and precision.
Note 2 to entry: It is possible to define more than one measurement method for a key control characteristic if the
correlation of the results is well-defined and known.
[SOURCE: IEC TS 62565-1:2023, 3.1, modified – "material property or intermediate" has been
added at the start of the definition.]
3.1.2
blank detail specification
BDS
structured generic specification providing a comprehensive set of key control characteristics
which are needed to describe a specific product without assigning specific values or attributes
Note 1 to entry: Examples of nano-enabled products are: nanocomposites and nano-subassemblies.
Note 2 to entry: Blank detail specifications are intended to be used by industrial users to prepare their detail
specifications used in bilateral procurement contracts. A blank detail specification facilitates the comparison and
benchmarking of different materials. Furthermore, a standardized format makes procurement more efficient and more
error robust.
[SOURCE: IEC TS 62565-1:2023, 3.2]
3.1.3
detail specif
...