SIST EN 62047-9:2011

Semiconductor devices - Micro-electromechanical devices - Part 9: Wafer to wafer bonding strength measurement for MEMS

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.

Halbleiterbauelemente - Bauelemente der Mikrosystemtechnik - Teil 9: Prüfverfahren zur Festigkeit von Full-Wafer-Bondverbindungen in der Mikrosystemtechnik (MEMS)

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

La CEI 62047-9:2011 décrit une méthode de mesure de la résistance de collage de deux plaquettes, le type de processus de liaison, par exemple le collage par fusion de deux plaquettes de silicium, le collage anodique d'une plaquette de silicium et d'une plaquette de verre, etc., et la taille de la structure applicable pendant le traitement ou l'assemblage de systèmes microélectromécaniques (MEMS). L'épaisseur de plaquette applicable est dans la gamme comprise entre 10 ohmm et plusieurs millimètres. Le contenu du corrigendum de mars 2012 a été pris en considération dans cet exemplaire.

Polprevodniški elementi - Mikroelektromehanski elementi - 9. del: Merjenje (mehanske) spojne trdnosti med rezinami pri mikroelektromehanskih sistemih (MEMS)

Ta standard opisuje metodo merjenja (mehanske) spojne trdnosti med rezinami, vrsto spojnega postopka, na primer spajanje s fuzijo med silikonom in silikonom, anodno spajanje med silikonom in steklom itd., in ustrezno velikost strukture med obdelavo/sestavljanjem MEMS. Ustrezna debelina rezin je v razponu med 10 μm in nekaj milimetri.

General Information

• Status: Published
• Publication Date: 15-Sep-2011
• ICS: 31.080.01 - Semiconductor devices in general
• Technical Committee: I11 - Imaginarni 11
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 07-Sep-2011
• Due Date: 12-Nov-2011
• Completion Date: 16-Sep-2011
• Ref Project: EN 62047-9:2011 - Semiconductor devices - Micro-electromechanical devices - Part 9: Wafer to wafer bonding strength measurement for MEMS

Standards Content (Sample)

SLOVENSKI STANDARD
SIST EN 62047-9:2011
01-oktober-2011
Polprevodniški elementi - Mikroelektromehanski elementi - 9. del: Merjenje
(mehanske) spojne trdnosti med rezinami pri mikroelektromehanskih sistemih
(MEMS)
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
Ta slovenski standard je istoveten z: EN 62047-9:2011
ICS:
31.080.01 Polprevodniški elementi Semiconductor devices in
(naprave) na splošno general
SIST EN 62047-9:2011 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 62047-9:2011

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SIST EN 62047-9:2011

EUROPEAN STANDARD
EN 62047-9

NORME EUROPÉENNE
August 2011
EUROPÄISCHE NORM

ICS 31.080.99


English version


Semiconductor devices -
Micro-electromechanical devices -
Part 9: Wafer to wafer bonding strength measurement for MEMS
(IEC 62047-9:2011)


Dispositifs à semiconducteurs -  Halbleiterbauelemente -
Dispositifs microélectromécaniques - Bauelemente der Mikrosystemtechnik -
Partie 9: Mesure de la résistance de Teil 9: Prüfverfahren zur Festigkeit von
collage de deux plaquettes pour les Full-Wafer-Bondverbindungen in der
MEMS Mikrosystemtechnik (MEMS)
(CEI 62047-9:2011) (IEC 62047-9:2011)





This European Standard was approved by CENELEC on 2011-08-17. CENELEC 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 Central Secretariat or to any CENELEC 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 CENELEC member into its own language and notified
to the Central Secretariat has the same status as the official versions.

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

CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Management Centre: Avenue Marnix 17, B - 1000 Brussels


© 2011 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 62047-9:2011 E

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SIST EN 62047-9:2011
EN 62047-9:2011 - 2 -
Foreword
The text of document 47F/82/FDIS, future edition 1 of IEC 62047-9, prepared by SC 47F, Micro-
electromechanical systems, of IEC TC 47, Semiconductor devices, was submitted to the IEC-CENELEC
parallel vote and was approved by CENELEC as EN 62047-9 on 2011-08-17.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN and CENELEC shall not be held responsible for identifying any or all such patent
rights.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
(dop) 2012-05-17
national standard or by endorsement
– latest date by which the national standards conflicting
(dow) 2014-08-17
with the EN have to be withdrawn
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 62047-9:2011 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standards indicated:
IEC 62047-2 NOTE  Harmonized as EN 62047-2.
IEC 62047-4 NOTE  Harmonized as EN 62047-4.
__________

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SIST EN 62047-9:2011
- 3 - EN 62047-9:2011
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

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.

NOTE  When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD
applies.

Publication Year Title EN/HD Year

IEC 60749-19 - Semiconductor devices - Mechanical and EN 60749-19 -
climatic test methods -
Part 19: Die shear strength


ISO 6892-1 2009 Metallic materials - Tensile testing - EN ISO 6892-1 2009
Part 1: 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

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SIST EN 62047-9:2011

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SIST EN 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

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

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale

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SIST EN 62047-9:2011
– 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

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SIST EN 62047-9:2011
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

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SIST EN 62047-9:2011
– 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
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
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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.

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SIST EN 62047-9:2011
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.

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.

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SIST EN 62047-9:2011
– 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.

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SIST EN 62047-9:2011
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 B. 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.

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SIST EN 62047-9:2011
– 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

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SIST EN 62047-9:2011
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.

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SIST EN 62047-9:2011
– 10 – 62047-9  IEC:2011
IR
camera
a
Wafer 1
h
1
Specimen
Wedge
d
under test
Wafer 2
h
2
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
1
kinds of wafer 1 and wafer 2.
wafer 1: bonded with wafer 2 h : thickness of wafer 2
2
wafer 2: bonded with wafer 1 a: clacking length of split state layer
between bonded wafer 1 and wafer 2
wedge: part of a blade to drive a clacking layer in d: thickness of wedge part of the blade
the specimen
IR source: infrared beam source
IR camera: to measure clacked 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
2
3 E E h h d
1 2 1 2
G = (3)
c
3 3 4
8
(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.

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SIST EN 62047-9:2011
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 = (4)
c
4
16 a
In case of h < 1 2
3 2
3 E h d
1 1
G =
 (5)
c
4
8
a
3.4.2 Equipment
1
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 (3)
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 (3), (4) or (5)
c
and write the value in Table 3.
___________
1
 Numbers in square brackets refer to the Bibliography.

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SIST EN 62047-9:2011
– 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 )

1
Thickness of wafer 2 (h )
2
Elastic coefficient of wafer 1 (E )
1
Elastic coefficient of wafer 2 (E )
2
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
2
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
2
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.
...