IEC PAS 62137-3:2008

IEC/PAS 62137-3
Edition 1.0 2008-11
PUBLICLY AVAILABLE
SPECIFICATION
PRE-STANDARD
Electronics assembly technology – Selection guidance of environmental and
endurance test methods for solder joints

IEC/PAS 62137-3:2008(E)
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IEC/PAS 62137-3
Edition 1.0 2008-11
PUBLICLY AVAILABLE
SPECIFICATION
PRE-STANDARD
Electronics assembly technology – Selection guidance of environmental and
endurance test methods for solder joints
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
X
ICS 31.190 ISBN 978-2-88910-809-1
– 2 – PAS 62137-3 © IEC:2008(E)

CONTENTS
FOREWORD.4
INTRODUCTION.5
1 Scope.6
2 Normative references .7
3 Terms and definitions .8
4 Procedure of selecting the applicable test method .9
4.1 Stress to solder joints in the field and test methods .9
4.2 Selection of test methods based on the shapes and terminals of electronic
components.11
5 Common subjects in each test method .12
5.1 Mounting device and materials used.12
5.2 Soldering condition.13
5.3 Accelerated endurance test .15
5.4 Selection of test conditions and analysis of test results .15
6 Test method .16
6.1 Body strength test of SMD before and after the rapid temperature change test.16
6.2 Cyclic bending strength test .18
6.3 Mechanical shear fatigue test .19
6.4 Cyclic drop test .20
6.5 Strength test of leaded component .22
6.6 Fillet lifting phenomenon observation of leaded component .23
Annex A (informative) Condition of rapid temperature change test .24
Annex B (informative) Soldered joint test by electrical conduction.26
Annex C (informative)  Torque shear strength test .27
Annex D (informative) Monotonic bending strength test .30
Annex E (informative) Cyclic steel ball drop strength test .32
Annex F (informative) Pull strength test.34
Annex G (informative) Creep strength test.35
Annex H (informative) Fillet lifting phenomenon observation of leaded component solder
joint and the life test by electrical conduction.40

Figure 1 – The joint regions for the reliability tests .6
Figure 2 – Factors affecting the joint reliability made by lead-free solder .7
Figure 3 – An example of the mounting position of SMD for monotonic bending, cyclic
bending and cyclic drop tests.13
Figure 4 – An example of reflow soldering temperature profile .14
Figure 5 – An example of flow soldering temperature profile .14
Figure 6 – Pull strength test.16
Figure 7 – Shear strength test.17
Figure 8 – Torque shear strength test .17
Figure 9 – Monotonic bending strength test .18
Figure 10 – Cyclic bending strength test .19

PAS 62137-3 © IEC:2008(E) – 3 –
Figure 11 – Structure of cyclic bending strength test.19
Figure 12 – Schematic illustrations of mechanical shear fatigue for solder joint .20
Figure 13 – Cyclic drop test .21
Figure 14 – Cyclic steel ball drop test .21
Figure 15 – Pull strength test .22
Figure 16 – Creep strength test .23
Figure 17 – Fillet lifting phenomenon of soldered joint .23
Figure A.1 – Stress relation curve for a given strain to a soldered joint (Sn96,5Ag3Cu,5) .24
Figure A.2 – Time to reach steady state in the temperature cycle chamber .25
Figure B.1 – Soldered joint test by electrical conduction .26
Figure C.1 – Fixing of substrate for torque shear strength test .29
Figure C.2 – Torque shear strength test jig and position adjustment .29
Figure C.3 – Torque shear strength test to a connector.29
Figure D.1 – An example of board bending jig.30
Figure E.1 – Cyclic steel ball drop test.32
Figure E.2 – Comparison of cyclic drop test and cyclic steel ball drop test .33
Figure F.1 – Pull strength test.34
Figure G.1 – Schematic illustration of the creep strength of a soldered joint .35
Figure G.2 – An example of flow soldering temperature profile (Actual measurement for
double wave soldering) .38
Figure G.3 – Creep strength test.39
Figure H.1 – Fillet lifting phenomenon of soldered joint.40
Figure H.2 – Conduction measurement for Fillet lifting phenomenon .41

Table 1 – Correlations between test methods and actual stresses in the filed .10
Table 2 – Recommended test methods suitable for specific shapes and terminals of
SMDs.11
Table 3 – Test method to recommend from application and weight of the lead terminal part.12
Table 4 – Solder composition.12
Table 5 – Temperature condition for rapid temperature change test.15
Table G.1 – Nominal cross section of leads and diameters of through holes and lands .37
Table H.1 – Diameters of through holes and lands in respect to the nominal cross
section and nominal diameter of lead wire .41

– 4 – PAS 62137-3 © IEC:2008(E)

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTRONICS ASSEMBLY TECHNOLOGY –
SELECTION GUIDANCE OF ENVIRONMENTAL
AND ENDURANCE TEST METHODS
FOR SOLDER JOINTS
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
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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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rights. IEC shall not be held responsible for identifying any or all such patent rights.
A PAS is a technical specification not fulfilling the requirements for a standard but made
available to the public.
IEC-PAS 62137-3 was submitted by the JEITA (Japan Electronics and Information Technology
Industries Association) and has been processed by IEC technical committee 91: Electronics
assembly technology.
The text of this PAS is based on This PAS was approved for
the following documents publication by the P-members of the
committee concerned as indicated in
the following document:
Draft PAS Report on voting
91/784/DPAS 91/821/RVD
Following publication of this PAS, which is a pre-standard publication, the technical committee
or subcommittee concerned will transform it into an International Standard.
This PAS shall remain valid for an initial maximum period of three years starting from the
publication date. The validity may be extended for a single three-year period, following which it
shall be revised to become another type of normative document or shall be withdrawn.

PAS 62137-3 © IEC:2008(E) – 5 –
INTRODUCTION
Tin-Lead eutectic solder had been used for both internal and external joints of electric and
electronic equipment for its characteristics and cost for long time. The recent request to reduce
burdens to the environment, however, resulted in various types of lead-free solders being
developed by many organizations. Now the solders used in production are being switched from
tin-lead based solders to lead-free solders in many production lines. The study of the solder
joints using lead-free solders has revealed that the reliability of the joints is not the same as that
of joints prepared using tin-lead solder. The Japan Electronics & Information Technology
Industries Association (JEITA) has been developing test methods to evaluate the performance
of the joints based on analysis of various experiments made by member experts. It should be
noted that any single test is not necessarily applicable to all the electronic components. There
are appropriate tests suitable for the size and shape of a component and also for specific types
of leads of components. This series of standards are thus prepared to provide the industry with
the necessary evaluation methods to produce reliable products to the society.

– 6 – PAS 62137-3 © IEC:2008(E)

ELECTRONICS ASSEMBLY TECHNOLOGY –
SELECTION GUIDANCE OF ENVIRONMENTAL
AND ENDURANCE TEST METHODS
FOR SOLDER JOINTS
1 Scope
This guidance describes the selection of an appropriate test method for reliability test of solder
joints for various shapes and types of surface mount devices (SMD) and leaded devices,
including various types of solder material.
The regions of the joints to be tested are shown in Figure 1. The test methods given here are
applicable to evaluate the strength of joints of a component mounted on printed wiring board but
not to test the mechanical strength of components themselves.
The test conditions for accelerated tests (rapid temperature change and high temperature tests)
may exceed the maximum allowable temperature range for a component.

SMD (leadless electrode type)
Component terminal
Component
Solder
Component terminal
Plating layers
Evaluation
Solder
Intermetallic
area
Compound layers
Substrate
Land Substrate land
Substrate
SMD (leaded type)
Component terminal
Solder
Component
terminal
Plating layers
Land
Substrate
Evaluation
Solder Intermetallic
area
Insertion type co mponent
Compound layers
(single-sided board)
Lead terminal
Substrate land
Substrate
Substrate
Solder
Land
Figure 1 – The joint regions for the reliability tests
The lead-free solders have different properties from those of the conventional tin-lead eutectic
solder. The reliability of soldered joints using lead-free solder may be reduced by the
composition of the solder used, the shape of terminals and surface treatment.

PAS 62137-3 © IEC:2008(E) – 7 –
The factors affecting the joint reliability using Sn96,5Ag3Cu,5 solder are shown in Figure 2.
This solder has the properties of higher melting temperature and harder than the tin-lead
eutectic solder and the solid is not easily deformed. Consequently, the stress induced to the
joint becomes higher than the tin-lead eutectic solder.
These properties may induce break of a soldered joint by accelerated temperature changes, or
mechanical stress.
Accelerating factors
Temperature cycle
Properties
(thermal stress)
Factors affecting joint reliability
Mechanical stress
1)Hard, not easily deformed      Increased stress to solder
Impact stress
2)High melting temp.      Increased stress between
Weight/load of component
High solidifying temp.       Joint/ substrate (e.g., fillet lifting)
High soldering temp.      Growth of reacting layer
3)Increased reactivity (Sn rich)      Electrode/land melting, diffusion
4)Segregation by inclusion of low           Reduction of reliability by formation of
melting temp. metals (Pb, Bi)  segregation layer
Solder failure
5)Change in materials/structure      Failure of electrode itself
Initiation and
Interface failure
of terminals growth of crack
Electrode failure
6)Decreased solderability      Deformation of fillet, defect formation
and fracture *Not of component
and board
Affecting parameter
Component: structure of terminals
Size
Board: Land, thickness, material
Structure of joints
Figure 2 – Factors affecting the joint reliability made
by lead-free solder
2 Normative references
The following referenced documents are indispensable for the application of this document. For
a dated reference, only the edition cited applies. For an undated reference, the latest edition of
the referenced document (including any amendment) applies.
IEC 60068-1:1988, Environmental testing. Part 1: General and guidance,
Amendment 1:1992
IEC 60068-2-2:2007, Basic environmental testing procedures Part 2:Tests, Test B: Dry heat
IEC 60068-2-14:1984, Environmental testing – Part 2: Test N: Change of Temperature
Amendment 1:1986
IEC 60068-2-78:2001 Environmental testing – Part:2-78: Tests – Test: Cab: Damp heat, steady
state
IEC 60194:2006, Printed board design, manufacture and assembly – Terms and definitions
IEC 61188-5(all parts) :Printed boards and printed board assemblies – Design and use
IEC 61190-1-1:2002, Attachment materials for electronic assembly – Part 1-1 Requirements for
soldering fluxes for high-quality interconnections in electronics assembly
IEC 61190-1-2:2007, Attachment materials for electronic assembly – Part 1-2 Requirements for
solder pastes for high-quality interconnections in electronics assembly

– 8 – PAS 62137-3 © IEC:2008(E)

IEC 61249-2-7:2002, Materials for printed boards and other interconnecting structure – Part 2-7;
Reinforced base materials clad and unclad – Epoxide woven E-glass laminated sheet of defined
flammability (vertical burning test), copper-clad
IEC 62137:2005, Environmental and endurance testing – Test methods for surface-mount
boards of area array type packages FBGA, BGA, FLGA, LGA, SON and QFN
IEC 62137-1-1:2007, Surface mounting technology – Environmental and endurance test
methods for surface mount solder joint – Part 1-1: Pull strength test
IEC 62137-1-2:2007, Surface mounting technology – Environmental and endurance test
methods for surface mount solder joint – Part1-2: Shear strength test
IEC 62137-1-3(91/708/CDV), Surface-mount technology – Environmental and endurance test
methods for surface mount solder joint – Part 1-3: Cyclic drop test
IEC 62137-1-4(91/746/CDV), Surface mounting technology – Environmental and endurance test
methods for surface mount solder joints – Part 1-4: Cyclic bending test
IEC 62137-1-5(91/743/CDV), Surface mounting technology – Environmental and endurance test
methods for surface mount solder joints – Part 1-5: Mechanical shear fatigue test
3 Terms and definitions
For the purposes of this document, the terms and definitions in IEC 60194, as well as the
following, apply.
3.1
lead-free
the lead content in the objective portion of an electronic components or similar products is equal
or less than 0,1 wt%
3.2
pull strength for SMD
applied force to break the joint of the lead of a gull-wing type SMD solder mounted and the
copper land of printed wiring board using a jig to pull the lead
3.3
shear strength for SMD
applied force to break the all the joints of leads of an SMD and lands on the printed wiring board
when a force is applied parallel to the side of the SMD
3.4
torque shear strength for SMD
applied force to break the soldered joints of leads of an SMD to the lands on printed wiring
board when a rotating force is applied to the SMD at the both end with the centre of the moment
at the center of the SMD with the rotation moment in parallel to the printed wiring board surface
3.5
monotonic bending strength for SMD
strength of soldered joints of SMD mounted on board when the board is bent convex toward to
the mounted SMDs expressed by the maximum bending depth to the break of joints

PAS 62137-3 © IEC:2008(E) – 9 –
3.6
cyclic bending strength for SMD
number of bending to the break of soldered joints of SMDs to the copper lands on board which
is fixed to a jig when the board is bent convex toward to the mounted SMDs
3.7
mechanical shear fatigue strength for SMD
imposition of cyclic shear deformation on the solder joints by mechanical displacement instead
of relative displacement generated by CTE (coefficient of thermal expansion) mismatch in
thermal cycling testing
NOTE The mechanical shear fatigue tests continues until the maximum force decreases to a certain value, which
corresponds to the appearance of an initial crack, or the electrical resistance-measuring instrument can detect electric
continuity interruption, and the number of cycles is recorded as fatigue life
3.8
cyclic drop test for SMD
number of drops to the break of soldered joints of an SMD to the copper lands on a board which
is fixed to a jig when the board is dropped from a specified height
3.9
cyclic steel ball drop strength for SMD
number of drops to the break of soldered joints of an SMD to the copper lands on a board when
the steel ball is dropped from a specified height on a board
3.10
pull strength for lead terminal type device
maximum applied force to break the soldered joint of a lead of an SMD to a land on board when
the lead is pulled using a jig
3.11
creep test for lead terminal type device
strength of a soldered joint expressed by the time to break the joint held in a thermostat when a
continuous force is applied to a lead of an SMD soldered to a land
3.12
fillet lifting phenomenon
phenomenon a solder fillet of a lead of an SMD is fillet lifting from a land on a board, or of the
land from the board (De-lamination)
3.13
daisy chain
all chain of connections solder joint are connected in series
NOTE Lands on both sides of a board and leads are solder- connected in a chain in the case of a lift off test
4 Procedure of selecting the applicable test method
4.1 Stress to solder joints in the field and test methods
The correlations between the test methods and the actual stress induced to components are
shown in Figure 1. The printed wiring board and the shapes of terminals effective to correlate
the test results to actual conditions of the component mounting in the filed are also shown as
reference. The selection of a test method suitable for a specific shape of terminal is given in 4.2.

– 10 – PAS 62137-3 © IEC:2008(E)

Table 1 – Correlations between test methods and actual stresses in the filed
Test method Accelerated Applicable board/ Stress in the field and
stress applicable products
(Applicable standard) Components
application
a), b)
Conduction test
Temperature SMD Repeated thermal stress caused
cycling by the difference in thermal
IEC 62137:Annex B
a) expansion coefficients of
Pull strength (rapid
SMD
component and board at the
temperature
IEC 62137-1-1
(Gull-wing)
c) ON/OFF of equipment and/or
change)
a)
temperature changes in the
Shear strength
SMD
surrounding environment
IEC 62137-1-2
a)
Torque shear strength
SMD
Annex C
a)
Monotonic bending test SMD
Annex D
Cyclic bending strength test
Repeated board SMD Repeated mechanical stress
bending applied to soldered joints and
IEC 62137-1-4
board as in the case of keying,
especially for portable equipment
Mechanical shear fatigue test
Cyclic strain  SMD Repeated thermal stress caused
by the difference in thermal
IEC 62137-1-5
expansion coefficients of
component and board at the
ON/OFF of equipment and/or
temperature changes in the
surrounding environment
d)
Cyclic drop test
Repeated board SMD Shock induced to soldered joints
drop when equipment is erratically
IEC 62137-1-3
d) dropped while the equipment is in
Cyclic steel ball drop strength test Repeated ball drop SMD
use
Annex E
Pull strength test
Temperature Single-sided Repeated thermal stress caused
cycling TH/Leaded by the difference in thermal
Annex F
insertion type expansion coefficients of
(rapid
component and board at the
temperature
c) ON/OFF of equipment and/or
change)
temperature changes in the
surrounding environment
Creep strength test
Loading + Single-sided Degradation of soldered joint
Temperature TH/Leaded when a continuous force is
Annex G
insertion type applied
Observe of fillet lifting phenomenon Evaluation method Single-sided The external observation method
TH/Leaded insertion of fillet lifting phenomenon that
Annex H
type may occur when soldering an
alloy and the terminal plating
NOTE 1
a)
This is a test to evaluate degradation of joint strength with repeated thermal stress induced to the joint by
means of rapid temperature change for an accelerated test. A proper test should be selected according to
the features of the component under test such as the shape of its leads.
b)
This is a test to check if there is a failure at a soldered joint by measuring changes of resistance of the joint
without applying mechanical stress. This test method is not a new test method developed in this document
but referred here as an alternative method as it is a useful test especially for BGA and LGA.
c)
Each temperature test is applied in the case of the following alloys.
1) temperature cycling test (Rapid temperature change): Sn-Ag-Cu, Sn-Zn, Sn-Bi and Sn-In
2) High temperature / high humidity test: Sn-Zn
3) High temperature test: Sn-Bi
d)
Applicable using Sn-Ag-Cu, Sn-Zn, Sn-Bi and Sn-In alloy
NOTE 2 The vibration test is a test of a durability against the vibration a product may receive while in
transportation or in the service in the field. It was not proved that a vibration test, including the most severe
random acceleration test, could evaluate degradation of soldered joints. The vibration test is, therefore, not
included in this document.
General electronics components Semiconductor devices
PAS 62137-3 © IEC:2008(E) – 11 –
4.2 Selection of test methods based on the shapes and terminals of electronic
components
4.2.1 Surface Mount Devices
The recommended test methods suitable for specific shapes and terminals of devices are listed
in Table 2.
Table 2 – Recommended test methods suitable
for specific shapes and terminals of SMDs
Types and terminals of device Rapid temperature change test
Mechanical
Cyclic
Number
Cyclic shear
Shear Torque Monotonic
bending
Resistance
of
Terminals drop test fatigue
Examples Pull test strength shear bending
test
terminal measurement
test
test test limit
s
Electrodes on 2
Tantalum capacitor,
sides A,B C
- -- - - -
inductor
(bent leads)
Rectangular chip
Electrodes on 3 sides 2 resistor/film
A,B C
- -- - - -
capacitor
Electrodes on 5 Laminated
sides 2 capacitor,
- A,B -- - - C -
(including cap) thermistor,
Multi terminals
Resistor array,
4 or more
(terminals on A,B CC
- -- - -
capacitor array
sides)
Gull wing – 1 4 or more Transformer
A,B C C C
-- - -
Gull wing – 2 Up to 6 Switch
BA,B C
- -- - -
Gull wing – 3 4 or more Connector
- A,B A,B - C - C -
Electrodes on Inductor, tantalum
A,B B C
- -- - -
bottom capacitor
MELF
Round electrode
2 capacitor/resistor/fu
A,B B C
- -- - -
(including cap)
se
Leads on two
sides 2Diode
A,B C C
- -- - -
(bent lead)
Gull wing leads 3 to 6 Small transistor
CB C -- - C -
Gull wing leads 6 or more QFP, SOP
A,B CC C B B
--
Non-lead 6 or more QFN, SON
A,B C B B B
-- -
Ball electrodes on
Multiple BGA, FBGA
-- - A,B C B B B
bottom
Electrodes on
bottom Multiple LGA, FLGA A,B C B B B
-- -
without ball
: A: Recommended for accelerated endurance test, B: Applicable, C: Applicable when condition are met, -: Not applicable
Note1
: One of the following static mechanical tests is performed before or after the rapid temperature change test
Note2
according to the shape of the component under test.
a) Pull strength test: SMD with gull wing terminals.
b) Shear strength test: Small rectangular SMD to which a pushing jig can be pressed to a side of the device.
)T hhSMDhhhh hihh lhhidiffil ldh
Note3:　The conduction test is applicable to devices to which a Daisy-chain can be formed on the mounting board
or within the device under test itself. Examples are those semiconductor devices not with leads
such as BGA, LGA or QFN.
Note4:　The monotonic bending limit test is applicable to those components with height or large size to which the resistance
measurement test is available and which are not easily deformed. This test is applicable in case the resistance
measurement does not give a good criterion for the durability analysis and a mechanical stress is expected to exist
in the service.
Note5:　The cyclic bending strength test and cyclic drop test are applicable to those components mainly used
in portable equipment.
The use of these tests should be specified in the specification of the product.
f
Note6:　Each temperature test is applied in the case of the following alloys.
a) temperature cycling test (Rapid temperature change): Sn-Ag-Cu, Sn-Zn, Sn-Bi and Sn-In
b) High temperature / high humidity test: Sn-Zn
c) High temperature test: Sn-Bi

– 12 – PAS 62137-3 © IEC:2008(E)

4.2.2 Insertion component (leaded component)
The pull strength test is the basic test for such leaded components. The creep test should also
be used for components of a large size, or an external force seems to be applied continuously
from its structure.
The selection of the test shall be stated in the product specification for the component to be
mounted on solely single-side of a board. In many cases, strength of terminal leads in insertion
type through-hole mounted components may be inferior as compared to soldered joints. These
tests are not appropriate for equipment using this type of boards.
Recommended test methods such as the weight of lead terminal part, the kind of the board and
bite of the load are given in Table 3.
Table 3 – Test method to recommend
from application and weight of the lead terminal part
Application, Component type Test
PWB
Evaluation of fillet
Type Weight of a Pull strength Creep strength Conduction
Application lifting
lead terminal test test test
phenomenon
Light A － － －
No continuous
load
Heavy B A － －
Single-
sided TH
Light A － － －
Continuous load
Heavy B A － －
General lead terminal part － － A B
Both-
sided TH
Daisy chain type part － － A A
NOTE 1 A: Applicable, B: Applicable when condition are met, －：Not applicable
NOTE 2 Environment of each test is as follows.
a) Pull strength test： Room temperature
b) Creep strength test： High temperature environment to prescribe in a product standard
c) Lift off test： Room temperature
d) Conduction test： Rapid temperature change test environment to prescribe in a product standard
NOTE 3 For these test, the Sn – Ag – Cu alloy and Sn – Zn alloy are suitable
NOTE 4 In case of using both-sided TH board, the strength of the lead terminal tends to be smaller than the strength
of solder joint. Therefore, this type board is not suitable for a joining strength test.
5 Common subjects in each test method
5.1 Mounting device and materials used
a) Solder
The composition of the lead-free solder for interconnection is not specified. The standard solder
composition is given in Table 4.which shall be used in case the composition is not specified in
the product specification.
Table 4 – Solder composition
Solder alloy Solder composition (Short name)
Sn-Ag-Cu Sn96,5Ag3Cu,5(A30C5) –
Sn-Zn Sn91Zn9(Z90) Sn89Zn8Bi3(Z80B30)
Sn-Bi Bi58Sn42(B580) –
Sn-In Sn88In8Ag3,5Bi,5(N80A35B5) –
Sn-Cu Sn99,3Cu,7(C7) –
PAS 62137-3 © IEC:2008(E) – 13 –
b) Board used in the tests
The board shall be the copper-clad laminate of glass-cloth epoxy type specified in IEC 61249-2-7.
When board of other material is used, it is recommended to choose board of fewer thermal
degradation, mechanical deformation and board breakage.
The monotonic bending strength test, cyclic bending strength test and cyclic drop test are not
applicable to specimens using a substrate made of materials which are hard to be deformed
such as ceramics.
Other test conditions are specified in the relevant test method.
c) Mounting of components to board
Mounting of components to board is specified below.
Tests for SMDs are performed by mounting the devices on single-sided or one side of double-
sided board.
Tests for leaded components for insertion mounting are for mounting the components on one
side of board. Tests for leaded components mount on both sides are not appropriate as the
strength of soldered joints in this case is much higher than that of leads themselves to the
component.
d) Position of components and land pattern
The SMD to be tested in the monotonic bending strength test, cyclic bending strength test and
cyclic drop test shall be mounted on the center of a board as illustrated in Figure 3. The
position of the device under test for other tests may be determined in appropriate place on
board as agreed between user and supplier. When a product standard does not have a rule, the
land pattern is based on standards of IEC 61188-5 series.
Unit:mm
PWB thickness 1,6t
部品Component
（span）
Figure 3 – An example of the mounting position of SMD
for monotonic bending, cyclic bending and cyclic drop tests

5.2 Soldering condition
A proper soldering condition shall be selected to form appropriate solder fillet. Examples of the
temperature profile for the lead free solder for reflow and flow soldering are shown in Figures 4
and Figures 5.
o
Temperature ( C)
o
Temperature ( C)
– 14 – PAS 62137-3 © IEC:2008(E)

T
T
t
T
2 2
T
t
Time (s)
Solder composition
Sn96,5Ag3Cu,5 Sn91Zn9*, Sn89Zn8Bi3 Bi58Sn42 Sn88In8Ag3,5Bi,5

T Minimum preheat temperature 150°C 130°C 100°C 140 °C
T Maximum preheat temperature 180°C 150°C 120°C 160 °C
T Soldering temperature 220°C 200°C 150°C 206 °C
T Peak temperature 250 ± 5 °C 220 ± 5 °C 190 ± 5 °C 220 ± 5 °C
t Preheat time 90 ± 30 s 90 ± 30 s 90 ± 30 s 90 ± 30 s
t Soldering time 20 ~ 60s 20 ~ 60s 20 ~ 60 s 20 ~ 60s
NOTE* Sn91Zn9 is recommended soldering of N2 reflow condition.
Figure 4 – An example of reflow soldering temperature profile

Solder bath temperature(Peak temperature) :T
p
Soldering time total : t
p
Preheating temperature: T
Preheating time: t
0 3 6 9 12 15
time（s）
Preheat Soldering
Preheat Preheat time Peak Soldering time
Solder composition
temperature temperature
t t
0 p
T Tp
s s
°C °C
Sn96,5Ag3Cu,5(A30C5) 100 ~ 120 30 ~ 90 250 ± 5 3 ~ 5
Sn99,3Cu,7(C7) 100 ~ 120 30 ~ 90 250 ± 5 3 ~ 5
Figure 5 – An example of flow soldering temperature profile
5.2.1 Other specifications
Details of other specifications are given in relevant test methods.

PAS 62137-3 © IEC:2008(E) – 15 –
5.3 Accelerated endurance test
5.3.1 Rapid temperature change test（apply to all solder alloy in this standard）
The rapid temperature change test as specified in IEC 60068-2-14 (Temperature change tests)
shall be performed for pull, shear, torque shear, and monotonic bending tests for SMDs and pull
test for leaded components. The temperature condition shall be chosen considering the effect
of temperature variation characteristics of a soldered joint to the stress relaxation of the joint
when a stress is applied to the joint. The temperature characteristics depend on the size of the
specimen (specific heat and heat dissipation of the specimen), size of the board, or the number
of boards tested in one measurement (see Annex A).
Recommended temperature conditions are given in Table 5.
Unless otherwise specified, the number of temperature cycles is 500 and 1000 cycles except for
the resistance measurement.
Table 5 – Temperature condition for rapid temperature change test

Solder composition
Sn96,5Ag3Cu,5 Bi58Sn42 Sn88In8Ag3,5Bi,5
Sn91Zn9，Sn89Zn8Bi3
Minimum Temperature
－40 °C －40 °C －40 °C －40 °C
storage
temperature
Hold time 30 min 30 min 30 min 30 min

Maximum Temperature 125°C 125°C 85°C 125 °C
storage
temperature
Hold time 30 min 30 min 30 min 30 min

5.3.2 High temperature test (apply to Bi58Sn42 alloy solder only)
Peel strength test, Shear strength test, Torque shear strength test, and monotonic bending test
of SMD and Pull strength test of leaded component in IEC 60068-2-2, as well as the follow, apply.

a) Test temperature: 85 °C
b) Test time: 500 h and 1 000 h
5.3.3 High temperature and High humidity test (constant)
(apply to Sn91Zn9 and Sn89Zn8Bi3 alloy solder)
Peel strength test, Shear strength test, Torque shear strength test, and monotonic bending test
of SMD and Pull strength test of leaded component in IEC 60068-2-78, as well as the follow, apply.

a) Test temperature and humidity: 65 °C, 85 %
b) Test time: 500 h and 1 000 h
5.4 Selection of test conditions and analysis of test results
a) Test speed
The test methods and conditions for the evaluation of durability of soldered joints shall be such
that the test does not break the specimen itself but damages are induced only to the soldered
joints. There is a tendency to increase the break of board and/or specimen in pull, shear, torque
shear, and monotonic bending tests for SMDs and pull test for leaded components when the test
speed is very high. It is recommended that the slower test speed with which a soldered joint
breaks in several tens of seconds to several minutes is chosen by performing a preliminary test
of a specimen.
– 16 – PAS 62137-3 © IEC:2008(E)

b) Board fixing
The measurement result may be affected if the board floats from the base or is distorted during
a test. The board shall be fixed firmly on a base preferably at a position near the testing
soldered joint.
The structure and/or size of the board fixing jig or the board supporting jig are specified in each
test method to assist reproducibility of the test.
c) Test result
The test result shall be analyzed by confirming and recording not only the strength and time to
break of a soldered joint but also the mode of break.
6 Test method
6.1 Body strength test of SMD before and after the rapid temperature
change test
The pull, shear, torque shear, and monotonic bending tests for SMDs are to judge the degree of
degradation of strength and other characteristics of a joint by the rapid temperature change. Pull
strength test.
6.1.1 Pull strength test
The pull strength test is applicable to SMDs with gull-wing type leads. As illustrated in Figure 6,
a pulling jig is hooked to one of the leads to pull the lead at an angle of 45 ° and to measure
the force to break the joint.
The degradation of a joint is analyzed from the changes of the maximum pulling force and mode
of break before and after the rapid temperature change test. This test is applicable to both of
reflow and flow soldering.
The proper pulling speed for a 0,5 mm pitch QFP is 0,0083 mm/s (0,5 mm/min).
The details of the test are given in IEC 62137-1-1.
45°
Substrate
Fastening jig
Figure 6 – Pull strength test
6.1.2 Shear strength test for force applied to the side of a specimen
The shear strength test is applicable for SMDs of rather small size. As illustrated in Figure 7,
the maximum testing force is measured when a force is applied horizontally to a side of a
specimen. The specimen is soldered to a board by reflow soldering.

PAS 62137-3 © IEC:2008(E) – 17 –
Pushing tool
Specimen
W = >W
W
j d
d
Specimen height: H
Shear height < H/4
Figure 7 – Shear strength test
It is necessary to keep the constant shear height which is lower than 1/4 of the height of the
specimen to obtain accurate measurement. The proper speed of applying the force is 0,0083 to
0,15 mm/s (0,5 to 9 mm/s).
The details of the test are given in IEC 62137-1-2.
6.1.3 Torque shear strength test
The torque shear st
...