IEC 62047-18:2013

IEC 62047-18 ®
Edition 1.0 2013-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Semiconductor devices – Micro-electromechanical devices –
Part 18: Bend testing methods of thin film materials

Dispositifs à semiconducteurs – Dispositifs microélectromécaniques –
Partie 18: Méthodes d’essai de flexion des matériaux en couche mince

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IEC 62047-18 ®
Edition 1.0 2013-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Semiconductor devices – Micro-electromechanical devices –

Part 18: Bend testing methods of thin film materials

Dispositifs à semiconducteurs – Dispositifs microélectromécaniques –

Partie 18: Méthodes d’essai de flexion des matériaux en couche mince

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX M
ICS 31.080.99 ISBN 978-2-8322-0982-0

– 2 – 62047-18 © IEC:2013
CONTENTS
FOREWORD . 3
1 Scope . 5
2 Normative references . 5
3 Symbols and designations . 6
4 Test piece . 6
4.1 Design of test piece . 6
4.2 Preparation of test piece . 7
4.3 Test piece width and thickness . 7
4.4 Storage prior to testing . 7
5 Testing method . 7
5.1 General . 7
5.2 Method for mounting of test piece . 9
5.3 Method for loading. 9
5.4 Speed of testing . 9
5.5 Displacement measurement . 9
5.6 Test environment . 9
5.7 Data analysis . 9
5.8 Material for test pieces . 10
6 Test report . 10
Annex A (informative) Precautions for the test piece/substrate interface . 11
Annex B (informative) Precautions necessary for the force displacement relationship . 12

Figure 1 – Schematically shown test piece with substrate . 6
Figure 2 – Measurement method . 8
Figure A.1 – Finishing angle of substrate contact area with test piece . 11
Figure B.1 – Cantilever type bend test piece of metallic glass in accordance with
IEC 62047-18. 12
Figure B.2 – Typical example of relationship between force and displacement . 13

Table 1 – Symbols and designation of test piece . 6

62047-18 © IEC:2013 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SEMICONDUCTOR DEVICES –
MICRO-ELECTROMECHANICAL DEVICES –

Part 18: Bend testing methods of thin film materials

FOREWORD
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patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 62047-18 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/155/FDIS 47F/162/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.
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.

– 4 – 62047-18 © IEC:2013
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.
62047-18 © IEC:2013 – 5 –
SEMICONDUCTOR DEVICES –
MICRO-ELECTROMECHANICAL DEVICES –

Part 18: Bend testing methods of thin film materials

1 Scope
This part of IEC 62047 specifies the method for bend testing of thin film materials with a
length and width under 1 mm and a thickness in the range between 0,1 µm and 10 µm. Thin
films are used as main structural materials for Micro-electromechanical Systems (abbreviated
as MEMS in this document) and micromachines.
The main structural materials for MEMS, micromachines, etc., have special features, such as
a few micron meter size, material fabrication by deposition, photolithography, and/ or non-
mechanical machining test piece. This International Standard specifies the bend testing and
test piece shape for micro-sized smooth cantilever type test pieces, which enables a
guarantee of accuracy corresponding to the special features.
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 62047-6:2009, Semiconductor devices – Micro-electromechanical devices – Part 6: Axial
fatigue testing methods of thin film materials

– 6 – 62047-18 © IEC:2013
3 Symbols and designations
Symbols and corresponding designations are given in Table 1.
Table 1 – Symbols and designation of test piece
Symbol Unit Designation
W µm Width of test piece
L Length of test piece
µm
S µm Thickness of test piece
L
PA Distance between loading point, A, B or C, and root of the test piece
µm
respectively
L L
,
PB PC
P µN Force
δ µm Displacement
I
Z (µm) Moment of inertia of area
E
MPa Elastic modulus of cantilever material

Figure 1 below shows a typical shape of cantilever beam test piece.
L
1 W
S
IEC  1712/13
Key
1 Top view 3 Substrate
2 Side view 4 Test piece
Figure 1 – Schematically shown test piece with substrate
4 Test piece
4.1 Design of test piece
The test pieces are of a shape of cantilever beam as shown in Figure 1 and the shape of their
cross-section shall be simple , in order to facilitate calculation of the moment of inertia of area.
The shape of the cross-section of the test piece should be simple, for example rectangular or
trapezoid. The relation between test piece length (L) of the parallel part of the test piece, the
width (W) and thickness (S) should be 10 > L/W > 5 and 100 > L/S > 10.
The fixed end of the test piece shall be placed within a substrate as shown in Figure 1.
Contact point of the test piece with substrate is important to avoid plastic deformation and/or

62047-18 © IEC:2013 – 7 –
fracture at the contact point of test piece root and substrate because of stress concentration
(see Annex A). When a different shape of test piece is used which elastic deformation
behavior does not follow Equation (1), the different shape of test piece and the equation in
place of Equation (1) shall be recorded.
In order to minimize the influence of size, the size of test piece should have the same order
as that of the objective device component.
4.2 Preparation of test piece
The test piece should be fabricated using the same process as when the thin film is applied to
actual devices, because the mechanical properties depend on the fabrication processes. The
test piece also shall be fabricated following the procedures specified in IEC 62047-6:2009,
Clause 4.2 Preparation of test piece. The substrate removal process should be carefully
chosen to prevent damaging the supporting part of the substrate (see Annex A) and the
supporting part of the test piece.
The thin film, which has internal stress distribution along the thickness, cannot be tested due
to curling after release from the substrate.
4.3 Test piece width and thickness
The width and thickness of each test piece shall be measured, as the film thickness is not
usually uniform over a wafer. Both the width and thickness through the parallel part of the test
piece shall be specified within the accuracy range of ± 1 % and ± 5 %. Each test piece should
be measured directly (see IEC 62047-6:2009, 4.3 Test piece thickness).
4.4 Storage prior to testing
In the case of thin films, storage environment can affect the mechanical properties (see
IEC 62047-6:2009, 4.4 Storage prior to testing).
5 Testing method
5.1 General
The employed testing machine includes features to facilitate displacement, loading and
positioning, and should be equipped with a measurement system of force and displacement.
In case of measurement, loading is made on a point of the cantilever beam test piece as
shown in Figure 2a) and 2b) using a sphere-shaped or a knife-edge shaped loading tool, and
the positions of loading points (A, B or C) of test pieces as shown in Figure 2a) should be
recorded with the relation between force (P) and displacement (δ) of the cantilever beam as
shown in Figure 2c). The loading point location through the parallel part of the test piece shall
be specified within the accuracy range of ± 1 % of the length of the test piece. The knife edge
tip radius is 5 µm and the straightness shall be within the accuracy of ± 1 % of the length of
the test piece. The angle between the knife-edge length direction and the test piece surface
and 4 ° respectively. These data
and the longitudinal direction of the test piece are within 2 °
shall be measured and recorded.

– 8 – 62047-18 © IEC:2013
A B C
L
PC
L
PB
L
PA
IEC  1713/13
a) Cantilever beam test piece with loading point

P
δ
IEC  1714/13
b) Cantilever beam test piece with loading tool

C
P
B
A
δ
IEC  1715/13
c) Relation between force and displacement
Key
1 Loading point at A,B or C 3 Test piece
2 Substrate 4 Sphere shaped tip loading tool
Figure 2 – Measurement method
62047-18 © IEC:2013 – 9 –
5.2 Method for mounting of test piece
A substrate including test pieces shall be mounted on the testing equipment so that the
loading axis and the test piece surface are aligned at a right angle. Fixing of test pieces to
substrates and to testing machines shall meet the following requirements:
a) The test pieces shall be securely fixed to the substrate, and shall not move during testing.
The substrate should be firmly fixed on the tool of the test equipment, whose stiffness is
higher than that of the substrate.
b) During testing, the substrate of test piece should be fixed, and the direction of loading axis
of the testing machine should be within 5 ° from perpendicular to the substrate surface.
5.3 Method for loading
The contacting portion of the sphere part of the tool to be loaded on test pieces should be in
the shape of a sphere as shown in Figure 2b) or a knife-edge. In case that the diameter of the
sphere shape is extremely smaller than the thickness (S) and a width (W) of test pieces, the
load should be carefully applied to avoid serious local deformation and fracture at the contact
point of test piece with the sphere. Deformation of test pieces should be minimized within a
range of pure elastic deformation. Movement of loading tool should go straight.
The displacement (δ) of cantilever beam shall be small for minimizing the contact point being
off the initial loading point of test piece during bending.
A load cell with a resolution adequate to guarantee 5 % accuracy of the applied force shall be
used. The drift of the load cell should be less than 1 % of the full-scale force during testing.
(See IEC 62047-6:2009, 5.4 Method of loading.)
5.4 Speed of testing
The displacement speed or loading speed should be constant, and it shall be within the
measurement equipment ability.
5.5 Displacement measurement
The resolution of the displacement sensor shall be more precise than 0,5 % of the maximum
range of a displacement measurement. If possible, the direct measurement of test piece
bending displacement (δ) is recommended because the load cell of low force range has a low
stiffness.
5.6 Test environment
Testing temperature and humidity shall be controlled to avoid fluctuations during testing, and
a particular attention is required for testing temperature.
5.7 Data analysis
The relation between force (P) and displacement (δ) of cantilever beam can be expressed as
Equation (1) within an elastic region. When using a test piece of another shape, the shape
shall be measured precisely with record. Data of force (P) and displacement (δ) shall be
available to use with record.
PL
P
δ = (1)
3EI
Z
The relation between force (P) and displacement (δ) of the cantilever beam depends on the
cross-sectional shape of the test piece, which is the moment of inertia of area (I ), and the
z
distance between the loading point and the root of the test piece. It is recommended that the

– 10 – 62047-18 © IEC:2013
test piece shape, the measurement method and the measurement accuracy are recorded.
Regarding the force and displacement relationship obtained as schematically shown in
Figure 2c), the initiation part of the increasing force is sometimes not linear. This
phenomenon is caused by twisted and/or curved shape of the test piece, partially
delaminating of the test piece supporting part from the substrate or micro-fracture occurring at
the contact point of the test piece with the loading tool. In this case, the results data should
be used in the linear region only. When plastic deformation, fracture of supporting part of
substrate and/or slip of loading tool on test piece occurs, the force and displacement
relationship becomes not linear (see Annex B).
5.8 Material for test pieces
Cantilever beam type test pieces which enable to produce more than 5 pieces on the same
substrate at the same time under the same conditions should be selected. The elastic
modulus of the materials shall be known for reference of data analysis, and their elastic
modulus shall be the same as or less than those of substrate materials in order to avoid
stress concentration at the fixed portion (i.e. root of the cantilever beam test piece).
Furthermore, higher yield stress is desirable for avoiding plastic deformation at the contact
point of the root of the test piece with the substrate.
6 Test report
Test reports shall include at least the following information.
a) Mandatory
1) reference to this international standard
2) test piece material and elastic modulus for test pieces and substrate in the case of a
single crystal: crystallographic orientation
3) method and details of test piece fabrication
– method of thin film deposition
– fabrication process
– heat treatment (annealing) conditions
4) shape and dimensions of test pieces; especially
– the moment of inertia of area (I )
z
5) bending test conditions
– type of testing machines with resolution and capacity of force sensor and
displacement sensor
– testing environment (temperature and relative humidity)
– displacement rate or loading rate
6) bending test results
– tested test piece number
– measurement and calculated value
– comments in particular (defects, delamination or twist in test piece)
b) Optional
1) Microstructure
2) Internal stress
3) Surface roughness of test piece
4) Deformation characteristics

62047-18 © IEC:2013 – 11 –
Annex A
(informative)
Precautions for the
test piece/substrate interface

The contact point of the test piece with the substrate is important to avoid the stress
concentration that causes plastic deformation and/or fracture at the test piece and supporting
part of the substrate. In order to avoid this phenomenon, the point of contact of the substrate
with the test piece should be at an angle of 45° to a maximum of 90° as shown by arrow 3 in
Figure A.1, and attention shall be paid to ensure that there is no critical etching damage at the
corner.
45° to 90°
IEC  1716/13
Key
1 Test piece
2 Substrate
3 Stress concentrate part
Figure A.1 – Finishing angle of substrate contact area with test piece

– 12 – 62047-18 © IEC:2013
Annex B
(informative)
Precautions necessary for the force displacement relationship
Figure B.1 shows a cantilever type bend test piece of metallic glass (Pd Cu Si (atomic
78 6 16
percentage)) manufactured and tested in accordance with this standard. The dimension of this
test piece is 500 µm of length and 50 µm of width.

IEC  1717/13
Figure B.1 – Cantilever type bend test piece of metallic glass
in accordance with IEC 62047-18
The test piece behaviour during the test following this standard is shown in Figure B.2.
Displacement relationship is a straight line as shown in Figure B.2a) by arrow 1, where the
test piece is deformed elastically. When the tip of the test piece touches to the substrate
during loading (Figure B.2a) by arrow 2 and Figure B.2b) by arrow 10), force and
displacement relation changes as shown in Figure B.2a) by arrow 3. When the test piece
deforms plastically or the contacting point of test piece or the tip of the loading tool fractures,
unloading curve does not fit with the loading curve as shown in Figure B.2a) by arrow 3, 4
and 5.
62047-18 © IEC:2013 – 13 –
3 000
2 500
2 000
1 500
1 000
0 1 000 2 000 3 000 4 000 5 000
δ  (nm)
IEC  1718/13
a) Force displacement relationship of the test piece shown in Figure
...