IEC 62047-9:2011

IEC 62047-9 ®
Edition 1.0 2011-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Semiconductor devices – Micro-electromechanical devices –
Part 9: Wafer to wafer bonding strength measurement for MEMS

Dispositifs à semiconducteurs – Dispositif microélectromécaniques –
Partie 9: Mesure de la résistance de collage de deux plaquettes pour les MEMS

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IEC 62047-9 ®
Edition 1.0 2011-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Semiconductor devices – Micro-electromechanical devices –
Part 9: Wafer to wafer bonding strength measurement for MEMS

Dispositifs à semiconducteurs – Dispositif microélectromécaniques –
Partie 9: Mesure de la résistance de collage de deux plaquettes pour les MEMS

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX T
ICS 31.080.99 ISBN 978-2-88912-585-2

– 2 – 62047-9  IEC:2011
CONTENTS
FOREWORD. 4
1 Scope . 6
2 Normative references . 6
3 Measurement methods . 6
3.1 General . 6
3.2 Visual test . 6
3.2.1 Types of visual test . 6
3.2.2 Equipment . 7
3.2.3 Procedure . 7
3.2.4 Expression of results . 7
3.3 Pull test . 7
3.3.1 General . 7
3.3.2 Equipment . 8
3.3.3 Procedure . 8
3.3.4 Expression of results . 9
3.4 Double cantilever beam test using blade . 9
3.4.1 General . 9
3.4.2 Equipment . 11
3.4.3 Procedure . 11
3.4.4 Expression of results . 11
3.5 Electrostatic test . 12
3.5.1 General . 12
3.5.2 Equipment . 13
3.5.3 Procedure . 13
3.5.4 Expression of results . 14
3.6 Blister test . 14
3.6.1 General . 14
3.6.2 Preparation of the specimens . 15
3.6.3 Test apparatus and testing method . 15
3.6.4 Report . 16
3.7 Three-point bending test . 16
3.7.1 General . 16
3.7.2 Preparation of the specimens . 17
3.7.3 Test apparatus and testing method . 18
3.7.4 Report . 19
3.8 Die shear test . 19
3.8.1 General . 19
3.8.2 Preparation of the specimens . 20
3.8.3 Test apparatus . 21
3.8.4 Test method . 21
3.8.5 Shear bonding strength . 22
3.8.6 Report . 22
Annex A (informative) Example of bonding force . 23
Annex B (informative) An example of the fabrication process for three-point bending
specimens . 24
Bibliography . 25

62047-9  IEC:2011 – 3 –
Figure 1 – Bonding strength measurement – pull test . 8
Figure 2 – Bonding strength measurement – double cantilever beam (DCB) test
specimen using blade . 10
Figure 3 – Bonding strength measurement – electrostatic test . 13
Figure 4 – A specimen for blister test . 15
Figure 5 – Three-point bending specimen and loading method . 17
Figure 6 – Specimen geometry of three-point bending specimen . 18
Figure 7 – Die shear testing set-up . 19
Figure 8 – Size requirement of control tool and specimen . 20
Figure 9 – Example of bonded region in test piece . 20
Figure 10 – Setting of contact tool . 22
Figure A.1 – An example of bonding force or load measurement with time at constant
rate of upper fixture moving . 23
Figure B.1 – An example of specimen preparation for three-point bending test . 24

Table 1 – Example of visual test . 7
Table 2 − Example of pull test . 9
Table 3 – Example of Double Cantilever Beam test using blade . 12
Table 4 – Example of electrostatic test . 14

– 4 – 62047-9  IEC:2011
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SEMICONDUCTOR DEVICES –
MICRO-ELECTROMECHANICAL DEVICES –

Part 9: Wafer to wafer bonding strength measurement for MEMS

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
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 62047-9 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/82/FDIS 47F/92/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.

62047-9  IEC:2011 – 5 –
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.
The contents of the corrigendum of March August 2012 have been included in this copy.

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.
– 6 – 62047-9  IEC:2011
SEMICONDUCTOR DEVICES –
MICRO-ELECTROMECHANICAL DEVICES –

Part 9: Wafer to wafer bonding strength measurement for MEMS

1 Scope
This standard describes bonding strength measurement method of wafer to wafer bonding,
type of bonding process such as silicon to silicon fusion bonding, silicon to glass anodic
bonding, etc., and applicable structure size during MEMS processing/assembly. The
applicable wafer thickness is in the range of 10 µm to several millimeters.
2 Normative references
The following referenced documents are indispensable for the application 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.
IEC 60749-19, Semiconductor devices – Mechanical and climatic test methods – Part 19: Die
shear strength
ISO 6892-1: 2009, Metallic materials – Tensile testing – Part1: Method of test at room
temperature
ASTM E399-06e2: 2008, Standard Test Method for Linear-Elastic Plane-Strain Fracture
Toughness K Ic of Metallic Materials
3 Measurement methods
3.1 General
There are different ways to measure bonding strength such as visual test, pull test, double
cantilever beam test using blade, electrostatic test, blister test, three-point bend test, and die
shear test.
3.2 Visual test
3.2.1 Types of visual test
From colour change of silicon substrate and surface of glass, this method tells you only a
general information like whether the material is bonded or not. The visual test shall be
performed to confirm whether substantial other bonding tests are required, and/or to identify
the area that the bonding tests shall be conducted.
Optical microscope shall be used to evaluate the bonding interface of glass to silicon and
glass to glass.
An infrared (IR) camera shall be used to observe voids existing in the bonding interface of
silicon to silicon
NOTE Visual test is a simple qualitative test method.

62047-9  IEC:2011 – 7 –
3.2.2 Equipment
One or a few equipments of optical microscope, scanning acoustic microscope, scanning
electron microscope (SEM), transmission electron microscope (TEM), and IR or optical
camera can be used.
3.2.3 Procedure
Steps to measure voids areas are as follows:
a) To observe voids, use the IR or optical microscope.
b) To take images of voids, use the IR or optical camera, or scanning acoustic microscope.
c) Measure voids areas using the observed images.
3.2.4 Expression of results
Check and simply indicate using the mark “V” the observation result based on Note 1 in
Table 1 for each case.
Table 1 – Example of visual test
good fair poor
Visual test
NOTE 1 good – complete bonded area fraction larger than 95 %, fair – complete bonded area fraction larger than
75 %, poor – complete bonded area fraction less than 75 %.
3.3 Pull test
3.3.1 General
As shown in Figure 1 this method is used to measure wafer bonding strength using general
tensile test method. After preparing for bonded wafer using various methods, a bonded wafer
is divided to square shaped specimens by dicing process. After dicing, dimensions of areas
(A) are measured. Top-side and back-side of a specimen of wafer bonded are glued to top
stud connected with load cell and bottom stud, respectively, using selective adhesive. And
then it is pulled upward until fracturing. In case that the wafer-to-wafer bonding to be tested is
very strong, fracture often occurs from the adhesive. In the case, pull test is not applicable.
Therefore, pull test is applicable only the case that bonding is not very strong and fracture
occurred at the bonding interface. During pulling process, applied force or fracture force (F )
c
is measured with time as shown in Annex A. Therefore, bonding strength could be calculated
by Equation (1).
F
c
σ = (1)
c
A
where
σ is bonding strength when debonding or fracture occurs;
c
F is applied force (fracture force) when the debonding or fracture occurs;
c
A is the area of the test sample.

– 8 – 62047-9  IEC:2011
Load cell
F
Upper stud
Adhesive
Specimen under test
Bottom stud
Base plate
IEC  1657/11
Key
Components Connections and supplies
specimen under
test: a dice of bonded wafer load cell: variable source of force
adhesive: to glue with upper stud and bottom stud F force: supplying for a testing specimen
upper stud: to connect with a load cell
bottom stud: to connect with a base plate
base plate: fixture to keep a rigid state

Figure 1 – Bonding strength measurement – pull test
3.3.2 Equipment
General tensile tester with force meter or load cell should be used as shown in ISO 6892.
3.3.3 Procedure
Steps to observe fractured specimens are as follows:
a) After bonding processes, for example, silicon to silicon bonding, silicon to glass bonding,
bonded wafers are cut into square shape with dimension, for example, 5 mm by 5 mm to
10 mm by 10 mm using dicing process. Maximum load to specimens is limited by the
capacity of load cell. So, maximum specimen size is also limited by the capacity of load
cell. And the accuracy of load cell shall be equal to or less than 1 % of full scale and 1 %
of reading.
b) Specimens attached to upper and lower studs using adhesive. Adhesives should be well
selected through consideration of specifications of them to endure until fracturing. And
adhesive should not be applied at sides of bonded wafers.
c) Lower stud is fixed to the bottom of apparatus and upper stud is connected to load cell or
force meter to measure stress at fracture of specimens at room temperature. Stress vs.
time curve shows maximum stress at fracture. Loading rate is in the range of 0,5 mm/min

62047-9  IEC:2011 – 9 –
to 1,5 mm/min. From fracture load data, we can calculate maximum strength. An example
of load vs. time curve is shown in Annex B.
d) After fracturing, observe fractured specimens by optical microscope or SEM.
e) At least 10 specimens shall be tested for reliable data.
3.3.4 Expression of results
Check and write the force measured value in Table 2.
Table 2 – Example of pull test
Reference standard
Type of material (fabrication method)
Bonding method
Shape and size of specimen
Type of adhesive (or glue)
Number of specimen
Loading speed
Measured fracture force (F )
c
Bonded area of the test specimen (A)

Bonding strength (σ )
c
3.4 Double cantilever beam test using blade
3.4.1 General
The wedge-opening test is also called the double cantilever beam test (DCB) as shown in
Figure 2. This testing method is suitable for bonded wafers using silicon to silicon fusion
bonding and anodic bonding. In case that examined wafer-to-wafer bonding is too strong, one
of the bonded wafers often breaks during this test procedure. In such a case, this method
cannot be used as a quantitative test but as a qualitative test.

– 10 – 62047-9  IEC:2011
IR
camera
a
Wafer 1
h
Specimen
Wedge
d
under test
Wafer 2 h
IR
source
IEC  1658/11
Key
Components or observation tool Dimensions of components
specimen under test: a piece of wafer bonded with different h : thickness of wafer 1
kinds of wafer 1 and wafer 2.
wafer 1: bonded with wafer 2 h : thickness of wafer 2
wafer 2: bonded with wafer 1 a: cracking length of split state layer
between bonded wafer 1 and wafer 2
wedge: part of a blade to drive a cracking layer in d: thickness of wedge part of the blade
the specimen
IR source: infrared beam source
IR camera: to measure cracked state length of the
specimen
Figure 2 – Bonding strength measurement –
double cantilever beam (DCB) test specimen using blade
The crack length is resulted from energy balance between strain energy of freely loaded
cantilevers and bonding energy at the bonding interface. Therefore, in this method, bonding
strength is evaluated not by fracture stress but by critical strain energy release rate. Critical
train energy release rate is calculated as follows
3 3
3 E E h h d
1 2 1 2
G = (2)
c
3 3 4
(E h + E h ) a
1 1 2 2
where
G is critical strain energy release rate (interfacial fracture toughness),
c
E and E are elastic coefficient of wafer 1 and 2;
1 2
h and h are thickness of wafer;
1 2
d is thickness of blade;
a is crack length.
62047-9  IEC:2011 – 11 –
In case of E =E and h = h , Equation (2) becomes
1 2 1 2
3 2
3 Eh d
G = (3)
c
16 a
In case of h < 1 2
3 2
3 E h d
1 1
G =
(4)
c
a
3.4.2 Equipment
Blade to test and sample fixture to fix should be used [1] .
Recommended blade thicknesses are in the range of 30 μm to 200 μm.
3.4.3 Procedure
a) After bonding processes, for example, silicon to silicon bonding, silicon to glass bonding,
the bonded wafer pair is cut into strips with the edges of wafers on at least one of their
ends. Width of strip specimens should be smaller than the width of the blade.
b) Set the stripe specimen to the sample fixture.
c) Insert a blade from one end of the stripe specimen using a gap resulted from rounded
wafer edges. Drive a crack along interface.
d) Measure the crack length using an optical or IR camera, or a scanning acoustic
microscope.
e) Calculate the interfacial fracture toughness using Equation (2)
f) At least 10 specimens should be tested for reliable data.
3.4.4 Expression of results
Write the measured values in Table 3. Then calculate G according to Equation (2), (3) or (4)
c
and write the value in Table 3.
___________
Numbers in square brackets refer to the Bibliography.

– 12 – 62047-9  IEC:2011
Table 3 – Example of Double Cantilever Beam test using blade
Shape of bonded specimen
Fixing method of specimen
Inserting speed of blade (optional)
Number of specimens
Crack length (a)
Thickness of blade (d)
Material of wafer 1
Material of wafer 2
Thickness of wafer 1 (h )
Thickness of wafer 2 (h )
Elastic coefficient of wafer 1 (E )
Elastic coefficient of wafer 2 (E )
Critical strain energy release late (G )

c
3.5 Electrostatic test
3.5.1 General
As shown in Figure 3, between Si wafer with patterned SiO films and glass wafer, anodic
bonding is done. Ranges of wafer thicknesses are normally 50 µm to 1 mm. By the
measurement of unbonded lengths depended on bonding strengths around patterned SiO
films on Si wafer, we can compare bonding strengths of anodic bonded wafers. So, this
method is convenient to utilize and allows you to compare qualitative bonding strength. The
measurement condition was at room temperature. Wafer level sizes in the range of 1 ” to 8 ”
2 2
or chip level sizes in the range of 1 cm to 4 cm are suitable for this experimental. Even
though this method could be used for bonded wafer using other bonding methods, in order to
avoid the difficulty to observe the unbonded length after bonding, it is better to use for only
anodic bonded wafer between Si and glass wafers.

62047-9  IEC:2011 – 13 –
SiO
t
g
Glass
Specimen
t
s
under test
Si
a
IEC  1659/11
Key
Configurations or specimen Dimensions of specimen under test
specimen under test:  bonded piece between Si wafer with t : thickness of glass
g
patterned SiO films and glass wafer
SiO : patterned film state layer bonded with a t : thickness of silicon
2 s
kind of glass layer and a silicon layer
Si: silicon base layer to be observed unbonded length at a a: unbonded length
cross sectional view
glass:  layer bonded with Si and SiO by anodic
bonding processes
Figure 3 – Bonding strength measurement –
electrostatic test
3.5.2 Equipment
Anodic bonder shall be used. General anodic bonder consists of vacuum chamber, holders for
holding top wafer and bottom wafer before bonding process, load cell to push top wafer
toward bottom wafer for initial bonding, electrical system to supply negative field to positive
+
ion contained wafer, for example, Na contained glass, and heater to maintain constant
temperature during process.
3.5.3 Procedure
Steps to measure the length of the unbonded area are as follows:
a) In order to make specimens, the anodic bonding between Si wafer with patterned SiO
films and glass wafer is performed. SiO thickness is more than 1 µm [2]. Anodic bonding
is a simple process to join together a silicon wafer and a alkali ion containing glass
substrate. The bonding is performed at a temperature between 200 °C and 500 °C in
vacuum, air or in an inert gas environment. The application of 500 V to 1500 V across the
two substrates, with the glass held at negative potential, causes mobile positive ions
+
(mostly Na ) in the glass to migrate away from the silicon glass interface toward the
cathode, leaving behind fixed negative charges in the glass. The bonding is complete
when the ion current vanishes, indicating that all mobile ions have reached the cathode.
The electrostatic attraction between the fixed negative charge in the glass and positive
mirror charge induced in the silicon holds the two substrates together and facilitates the
chemical bonding of glass to silicon [3]. Make the sample as shown in Figure 3 using
anodic bonding process.
b) Measure the length of the unbonded area using optical microscope or SEM (scanning
electron microscope) for cross-section observation.
c) At least ten specimens shall be tested for reliable data.

– 14 – 62047-9  IEC:2011
3.5.4 Expression of results
Write the measured values in Table 4. This method is not exact quantitative method, but
qualitative method. It is better that only this method could be used for quick and simple
comparison method.
Table 4 – Example of electrostatic test
Bonding temperature
Applied voltage
Applied time of voltage
Heating and cooling speed
Thickness of SiO
SiO pattern (dotted or linear)
Shape of bonded specimen
Testing temperature and humidity
Glass Material
Elastic coefficient of Glass (E )
g
Thickness of glass (t )
g
Thickness of silicon (t )
s
Unbonded length (a)
3.6 Blister test
3.6.1 General
Blister test is suitable for evaluation of strong bond which is difficult to be evaluated by tensile
test and double cantilever beam test. Tensile test has a problem of debonding from adhesive
glue. Double cantilever beam test has a problem of breaking one of the bonded wafers before
crack driving through the bonding interface. Blister test can minimize these problems. This
testing method can be applied to any type of wafer bonding, provided that specimens can be
prepared.
In this test, a bonded specimen with a hole, a channel and a thin cavity as shown in Figure 4
is used. Hydrostatic pressure line is connected to the specimen by mechanical clamping using
a flange and a back side plate with O-rings. Through the hole and channel, hydrostatic
pressure is applied to two inner surface of the cavity until debonding takes place.

62047-9  IEC:2011 – 15 –
2a
w w
3 2
w
w
h
t
t
p
IEC  1660/11
Key
1 a part of flange
2 a front side plate
3 O-rings
4 specimen
5 a back side plate
Figure 4 – A specimen for blister test
3.6.2 Preparation of the specimens
The hole, channel, and cavity structure should be made on one of the bonded wafers before
bonding using a micro-fabrication method such as photolithography and etching, which do not
introduce micro cracks. The shape of the cavity should be circle or square. Then the wafer is
bonded to another wafer. After bonding, the bonded wafer pair is diced into the shape shown
in Figure 4. Recommended dimensions of the specimen are as follows:
– a > 5t , 5t
1 2
– w , w > 2a
1 2
– w > 4a
– w < a/5
– h < t /20, t /20
1 2
3.6.3 Test apparatus and testing method
3.6.3.1 Number of specimens
At least ten specimens shall be measured.
3.6.3.2 Fixing of specimens
Hydrostatic pressure line is connected to the specimen by mechanical clamping using a
flange and a back side plate with O-rings.

– 16 – 62047-9  IEC:2011
3.6.3.3 Applying hydrostatic pressure and bonding strength measurement
Hydrostatic pressure is applied to the cavity using gas pressure. Pressure increasing rate
should be controlled by gas flow controller. The gas pressure should be gradually increased
so that quasi-static conditions are satisfied. The pressure should be monitored by pressure
gauge until the debonding. Debonding can be detected by specimen fracture, sudden
decrease of gas pressure. Optical observation by visible light for transparent materials or by
IR light for silicon is also effective to detect the initiation of debonding.
3.6.3.4 Environmental control
The temperature and humidity shall be kept at constant levels in the test environment during
the test.
3.6.4 Report
The test report shall include details on all of the following points, at minimum:
a) reference to this standard;
b) the bonded materials;
c) the method and conditions of bonding;
d) the shape of the specimen;
e) the pressure at the debonding.
3.7 Three-point bending test
3.7.1 General
As shown in Figure 5, this testing method is a measurement method for evaluating the bond
strength of bonding wafers by three-point bending. A specimen cut from the bonded wafer, in
which an unbonded region is introduced into the interface, is subjected to a three point
bending test to fracture the bonded interface. The bending fracture stress is then calculated
with Equation (5).
62047-9  IEC:2011 – 17 –
F
Supplying tool
Glass Si
Specimen under test
w
Thickness B
thickness B
a
Supporsupporting tting ooltoo l
Ssupporupportitng tingool too l
s s
IEC  1661/11
Key
Configurations or specimen Supply and dimensions of specimen under
test
specimen under test: region bonded piece between Si wafer w: width of the specimen

and glass layer with unbonded
Si bonded with a kind of glass layer B: thickness of the specimen
glass: a kind of layer bonded with Si layer a: length of the unbonded region
supporting tools : a kind of tools to receive loading force s: length of the span between tops of
through testing specimen supporting tools
F:
supplying tool a kind of tool to apply loading force loading force supplied by a kind of load cell
supplied from a load cell
Figure 5 – Three-point bending specimen and loading method
6F S
c
σ = (5)
c
B(W− a)
where
σ is fracture stress;
c
F is fracture force of the specimen;
c
S is span;
W is width of the specimen;
B is thickness of the specimen;
a is length of the unbonded region.
This testing method can be applied to any type of bonding wafers, provided that specimens
can be prepared. It has been developed for use with specimens of about 1 mm in thickness, in
order to minimize the size effect.
3.7.2 Preparation of the specimens
A process as similar as possible to that applied to the device should be used to fabricate the
test piece, including the bonding interface. The dimensions of specimens shown in Figure 6
are recommended as standard sizes. An unbonded region shall be introduced into the
specimen in the manner shown in the figure. The recommended combination of the length (S),
the width (W), and the length of the unbonded region (a) can be found by referring to Annex
A3 of ASTM E399-06e2:2008. The width of the unbonded regions should be 0,01 mm. An
example of the process to prepare the specimens is shown in Annex B. As the size may differ
from specimen to specimen, all of the dimensions shall be measured before testing. These
measurements shall have an accuracy of ± 1 %.

– 18 – 62047-9  IEC:2011
Glass
Si
a B = 0,5
0,01
s = 1,0 s = 1,0
IEC  1662/11
Figure 6 – Specimen geometry of three-point bending specimen
3.7.3 Test apparatus and testing method
3.7.3.1 Number of specimens
At least ten specimens shall be measured.
3.7.3.2 Fixing of specimens
The specimen shall be fixed to apply a three-point bending load, as shown in Figure 5. The
following conditions shall be ensured during this step:
a) the bonding boundary of the specimen and the loading axis of the test equipment are
aligned;
b) the specimen is set in a position where force can be applied parallel to the bonding
boundary.
A good way to achieve this condition is to magnify the specimen fixture and loading part with
an optical microscope. The rollers used to apply the load should be made from a material that
will not significantly deform under the force applied during the testing. The recommended
roller radius is 0,3 mm.
3.7.3.3 Applying force
The force should be applied with a mechanical testing machine capable of applying
compressive loads on micro materials. Instrumented indentation equipment can be also used.
The bonding boundary of the specimen and the loading axis of the testing equipment shall be
aligned to ensure that the force is applied uniformly at the bonding interface.
3.7.3.4 Speed of testing
The load should be applied to the specimen at a loading speed of 0,1 mm/min using a fine
drive mechanism that allows displacement control.
3.7.3.5 Force measurement
The force measurement shall be performed with a load cell (force sensor) with a guaranteed
resolution accuracy of 5 % of the measured fracture force.
3.7.3.6 Environmental control
The temperature and humidity shall be kept at constant levels in the test environment during
the test.
w = 0,5
62047-9  IEC:2011 – 19 –
3.7.3.7 Calculation of bending fracture stress
The bending fracture stress shall be calculated by Equation (5).
3.7.4 Report
The test report shall include details on all of the following points, at minimum:
a) reference to this standard;
b) the bonded materials;
c) the method and conditions of bonding;
d) the shape of the specimen;
e) the bending fracture stress.
3.8 Die shear test
3.8.1 General
The Die Shear Test is a method for measuring the shear bonding strength, as shown in
Figure 7. One side of the bonding wafer is fixed, and shear force is applied to the other side
of the wafer with a contact tool. The shear bonding force at the point of debonding is
calculated by Equation (6).
Contact tool
Direction of force
Test piece
Bonding part
IEC  1663/11
Key
Configurations or specimen Supplies
test piece: bonded piece of Si wafer with a bonded region direction of force: loading force supplied a kind
of load cell
bonding part: bonded layer within the bonded piece contact tool: to supply loading force to a
side surface of the bonded
piece
Figure 7 – Die shear testing set-up
Q
c
(6)
τ =
c
A
b
where
τ is shear bonding strength;
c
Q is shear force at the point of debonding;
c
A is bonded area.
b
IEC 60749-19 has already been established for die shear testing to assess the strength of
solder joints. The same standard can be applied for the measurement of wafer bonding
strength for MEMS devices by reducing the dimensions of the specimens down to several
millimeters and accounting for the method of specimen fabrication.

– 20 – 62047-9  IEC:2011
3.8.2 Preparation of the specimens
3.8.2.1 Shape and dimensions
The plane shape of the specimen should be several millimeters square. The length of one
side of the specimen shall be smaller than that of the contact tool (see Figure 8). The
thickness of each specimen should be determined based on the thicknesses of the wafers.
b
b < a
b
a
Test piece
Direction of force
Contact tool
IEC  1664/11
Key
Specimen and contact tool to supply loading force Supply and dimensions of specimen under test
test piece: bonded piece of a kind of diced wafer with direction of loading force supplied a kind of load
a bonded region force: cell
contact tool: supply loading force to a side surface of a: length of a side of the contact tool to
the bonded piece receive loading force by a load cell
b: length of sides of the bonded piece

Figure 8 – Size requirement of control tool and specimen
3.8.2.2 Bonded region
To avoid damaging the bonded region during dicing, the bonded region shall be formed in the
middle of the specimen. An unbonded region, meanwhile, should be prepared around the
edge of the specimen (See Figure 9). If the bond is not to be patterned, however, the bonded
region can be extended to the edges. The area and shape of the bonded region should have
the same dimensions in all specimens.
Unbonded region
A A’
Cross section of A-A’
Test piece
Bonded region
IEC  1665/11
Figure 9 – Example of bonded region in test piece
3.8.2.3 Method for fabricating the specimen
The wafers shall be bonded after the bonded region is patterned, then diced after the bonding
process is completed. The size of the planar shape and thickness of the specimens shall be
measured after the patterning, bonding, and dicing.

62047-9  IEC:2011 – 21 –
3.8.3 Test apparatus
The apparatus for this testing shall be equipped with a force-applying instrument with an
accuracy of 5 % of the full scale or 500 mN, whichever corresponds to greater tolerance. For
testing, the apparatus should consist of a lever or linear motion force-applying instrument
capable of applying the required stress. The test equipment shall also have the following
features and capabilities:
a) a contact tool capable of applying uniform force to the edge of the specimen;
b) the contact tool shall be vertical to the edge of the specimen;
c) a fixture with rotational capability relative to the specimen and the contact tool, to ensure
line contact with the edge of the specimen. This tool shall come into contact with the
whole edge of the specimen;
d) a facility fitted with a suitable light source to allow visual observation (e.g., at 10 x
magnification) of the specimen and contact tool during testing.
3.8.4 Test method
3.8.4.1 Number of specimens
At least ten specimens shall be m
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