IEC 61189-5-601:2021

IEC 61189-5-601 ®
Edition 1.0 2021-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Test methods for electrical materials, printed boards and other interconnection
structures and assemblies –
Part 5-601: General test methods for materials and assemblies – Reflow
soldering ability test for solder joint, and reflow heat resistance test for printed
boards
Méthodes d’essai pour les matériaux électriques, les cartes imprimées et autres
structures d’interconnexion et ensembles –
Partie 5-601: Méthodes d’essai générales pour les matériaux et
les assemblages – Essai d’aptitude au brasage par refusion pour un joint brasé,
et essai de résistance à la chaleur de refusion pour les cartes imprimées

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IEC 61189-5-601 ®
Edition 1.0 2021-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Test methods for electrical materials, printed boards and other interconnection

structures and assemblies –
Part 5-601: General test methods for materials and assemblies – Reflow

soldering ability test for solder joint, and reflow heat resistance test for printed

boards
Méthodes d’essai pour les matériaux électriques, les cartes imprimées et autres

structures d’interconnexion et ensembles –

Partie 5-601: Méthodes d’essai générales pour les matériaux et

les assemblages – Essai d’aptitude au brasage par refusion pour un joint brasé,

et essai de résistance à la chaleur de refusion pour les cartes imprimées

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 31.180 ISBN 978-2-8322-9293-8

– 2 – IEC 61189-5-601:2021 © IEC 2021
CONTENTS
FOREWORD . 6
1 Scope . 8
2 Normative references . 8
3 Terms and definitions . 9
4 Grouping of soldering processes and related test severities . 10
5 Specimens . 11
5.1 Devices . 11
5.2 Test substrate . 13
5.3 Solder paste . 13
5.4 Solder ball . 14
6 Apparatus and equipment . 14
6.1 Constant temperature and humidity testing equipment . 14
6.2 Device-mounting equipment . 15
6.3 X-ray transmission equipment . 15
6.4 Electrical resistance recorder . 15
6.5 Warpage measurement equipment . 15
6.6 Temperature cycling chamber . 16
6.7 Pull strength test equipment . 16
7 Tg Solder joint initial quality after reflow . 16
7.1 General . 16
7.2 Specimen preparation . 16
7.3 Pre-process . 16
7.3.1 Pre-conditioning . 16
7.3.2 Initial measurement . 16
7.3.3 Moistening process (1) . 17
7.3.4 Baking and warp correction . 17
7.3.5 Pre-reflow heating . 17
7.3.6 Moistening process (2) . 17
7.4 Assembly process . 17
7.4.1 Solder paste printing . 17
7.4.2 Device mounting . 18
7.4.3 Reflow heating . 21
7.5 Recovery . 22
7.6 Final measurement . 22
8 Tg warpage of component and printed boards in reflow process . 22
8.1 General . 22
8.2 Specimen preparation . 22
8.3 Assembly process . 23
8.3.1 Initial measurement . 23
8.3.2 Baking and warp correction . 23
8.3.3 Pre-reflow heating . 23
8.4 Final measurement . 23
8.4.1 Warpage measurement . 23
8.4.2 Measurement area . 23
8.4.3 Gap measurement . 23

9 Tg Resistance to soldering heat of printed boards . 25
9.1 General . 25
9.2 Specimen preparation . 26
9.3 Pre-process . 26
9.3.1 Pre-conditioning . 26
9.3.2 Initial measurement . 26
9.3.3 Moistening process (1) . 26
9.3.4 Baking and warp correction . 26
9.4 Reflow heating . 26
9.5 Final measurement . 27
10 Tg Wetting and dewetting of a printed-board land . 27
10.1 General . 27
10.2 Specimen preparation . 27
10.3 Pre-process . 27
10.3.1 Pre-conditioning . 27
10.3.2 Initial measurement . 28
10.3.3 Moistening process (1) . 28
10.3.4 Pre-baking . 28
10.3.5 Pre-reflow heating . 28
10.3.6 Moistening process (2) . 28
10.4 Assembly process . 28
10.4.1 Solder paste printing . 28
10.4.2 Reflow heating . 28
10.5 Final measurement . 29
10.5.1 Measurement . 29
10.5.2 Flux removal . 30
11 Tg Resistance to dissolution of a printed-board land . 30
11.1 General . 30
11.2 Specimen preparation . 31
11.3 Pre-process . 31
11.3.1 Pre-conditioning . 31
11.3.2 Initial measurement . 31
11.4 Assembly process . 31
11.4.1 Solder paste printing . 31
11.4.2 Reflow heating . 31
11.5 Final measurement . 31
11.5.1 Observation . 31
11.5.2 Observation method . 32
11.5.3 Measurement . 32
11.5.4 Example of influence upon occurrence of dissolution . 33
12 Tg Pull strength of the test substrate land . 33
12.1 General . 33
12.2 Specimen preparation . 34
12.3 Pre-process . 34
12.3.1 Pre-conditioning . 34
12.3.2 Initial measurement . 34
12.3.3 Pre-baking . 34
12.3.4 Pre-reflow heating . 34

– 4 – IEC 61189-5-601:2021 © IEC 2021
12.4 Assembly process . 34
12.4.1 Solder paste printing . 34
12.4.2 Solder ball placement . 34
12.4.3 Reflow heating process . 35
12.5 Final measurement . 35
12.5.1 Pull strength measurement . 35
12.5.2 Pull strength measuring method A – Probe heat bond method . 35
12.5.3 Pull strength measuring method B – Ball pinch method . 35
12.5.4 Pull strength measuring method C – Pin pull down method . 36
12.5.5 Pull strength measuring method D – Lead pull method . 36
12.5.6 Final observation . 36
Annex A (informative) Test process items and meaning of processing contents and
condition . 38
A.1 General . 38
A.2 Meaning of processing contents and condition . 38
A.3 Test process items . 38
Bibliography . 40

Figure 1 – Example of a test circuit for the electrical continuity test of a solder joint . 12
Figure 2 – Example of area array type packages . 12
Figure 3 – Example of leaded type devices . 12
Figure 4 – Example of leadless termination type devices . 12
Figure 5 – Example of connector for card type devices . 13
Figure 6 – Example of shielding metal components . 13
Figure 7 – Recommended solder ball shape. 14
Figure 8 – Test procedure for Tg . 16
Figure 9 – Example of printed conditions of solder paste . 18
Figure 10 – Typical reflow soldering profile for Sn63Pb37 solder alloy . 18
Figure 11 – Typical reflow soldering profile for Sn96,5Ag3Cu,5 solder alloy . 19
Figure 12 – Reflow temperature profile for soldering ability . 20
Figure 13 – Temperature measurement of the package device using thermocouples . 21
Figure 14 – Temperature measurement of other specimen using thermocouples . 21
Figure 15 – Test procedure for Tg . 22
Figure 16 – Contact point . 24
Figure 17 – Maximum gap . 25
Figure 18 – Test procedure for Tg . 26
Figure 19 – Test procedure for Tg . 27
Figure 20 – State of solder wetting. 30
Figure 21 – Solder contact angle . 30
Figure 22 – Test procedure for Tg . 31
Figure 23 – Evaluation of resistance to dissolution of land . 32
Figure 24 – Cross-section observation . 33
Figure 25 – Test procedure for Tg . 34
Figure 26 – Measuring methods for pull strength . 35

Figure 27 – Breaking modes in pull strength test . 37

Table 1 – Test items defined in this standard . 8
Table 2 – Grouping of soldering processes and typical test severities – Overview . 11
Table 3 – Stencil design standard for devices . 15
Table 4 – Maximum reflow heating conditions . 20
Table 5 – Minimum reflow heating conditions . 21
Table 6 – Wetting level . 29
Table A.1 – Meaning of processing contents and condition . 38
Table A.2 – Test process items and clauses . 39

– 6 – IEC 61189-5-601:2021 © IEC 2021
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
TEST METHODS FOR ELECTRICAL MATERIALS, PRINTED BOARDS
AND OTHER INTERCONNECTION STRUCTURES AND ASSEMBLIES –

Part 5-601: General test methods for materials and assemblies –
Reflow soldering ability test for solder joint, and reflow heat
resistance test for printed boards

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
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6) All users should ensure that they have the latest edition of this publication.
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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.
IEC 61189-5-601 has been prepared by IEC technical committee 91: Electronics assembly
technology. It is an International Standard.
The text of this International Standard is based on the following documents:
Draft Report on voting
91/1601/CDV 91/1674/RVC
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.

This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/standardsdev/publications.
A list of all parts in the IEC 61189 series, published under the general title Test methods for
electrical materials, printed boards and other interconnection structures and assemblies, can
be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
– 8 – IEC 61189-5-601:2021 © IEC 2021
TEST METHODS FOR ELECTRICAL MATERIALS, PRINTED BOARDS
AND OTHER INTERCONNECTION STRUCTURES AND ASSEMBLIES –

Part 5-601: General test methods for materials and assemblies –
Reflow soldering ability test for solder joint, and reflow heat
resistance test for printed boards

1 Scope
This part of IEC 61189 specifies the reflow soldering ability test method for components
mounted on organic rigid printed boards, the reflow heat resistance test method for organic rigid
printed boards, and the reflow soldering ability test method for the lands of organic rigid printed
boards in applications using solder alloys, which are eutectic or near-eutectic tin-lead (Pb), or
lead-free alloys.
The printed boards materials for this organic rigid printed boards are epoxide woven E-glass
laminated sheets that are specified in IEC 61249-2 (all parts).
The objective of this document is to ensure the soldering ability of the solder joint and of the
lands of the printed boards. In addition, test methods are provided to ensure that the printed
boards can resist the heat load to which they are exposed during soldering.
This document covers tests Tg , Tg , Tg , Tg , Tg , and Tg listed in Table 1:
1 2 3 4 5 6
Table 1 – Test items defined in this document
Number of
Test Method
test method
Tg
Solder joint initial quality after reflow
Tg
Warpage of component and printed boards in reflow process
Tg
Resistance to soldering heat of printed boards
Reflow
Tg
Wetting and dewetting of printed board land
Tg
Resistance to dissolution of printed board land
Tg
Pull strength of the test substrate land
NOTE The test methods do not apply to the solder bath method.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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 60068-2 (all parts), Environmental testing
IEC 60068-2-14, Environmental testing – Part 2-14: Tests – Test N: Change of temperature

IEC 60191-6-2, Mechanical standardization of semiconductor devices – Part 6-2: General rules
for the preparation of outline drawings of surface mounted semiconductor devices packages –
Design guide for 1,50 mm, 1,27 mm and 1,00 mm pitch ball and column terminal packages
IEC 60191-6-5, Mechanical standardization of semiconductor devices – Part 6-5: General rules
for the preparation of outline drawings of surface mounted semiconductor device packages –
Design guide for fine-pitch ball grid array (FBGA)
IEC 60191-6-19, Mechanical standardization of semiconductor devices – Part 6-19:
Measurement methods of the package warpage at elevated temperature and the maximum
permissible warpage
IEC 60194-1 , Printed boards design, manufacture and assembly – Vocabulary – Part 1:
Common usage in printed board and electronic assembly technologies
IEC 60194-2, Printed boards design, manufacture and assembly – Vocabulary – Part 2:
Common usage in electronic technologies as well as printed board and electronic assembly
technologies
IEC 61190-1-3, Attachment materials for electronic assembly – Part 1-3: Requirements for
electronic grade solder alloys and fluxed and non-fluxed solid solder for electronic soldering
applications
IEC 62137-3, Electronics assembly technology – Part 3: Selection guidance of environmental
and endurance test methods for solder joints
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 60191-6-2,
IEC 60191-6-5, IEC 60194-1 and IEC 60194-2, as well as the following, apply.
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
solderability
ability of the lead or termination of a component or electrode of a component or printed board
to be wetted by solder at the temperature of the lead, termination or electrode, which is assumed
to be the lowest temperature in the soldering process, within the applicable temperature range
of the solder alloy
Note 1 to entry: The term "solderability" is often used in combination with the term "test", indicating a specific
method to evaluate the wettability or ability to be soldered of a surface under worst case conditions (soldering
temperature and contact time with solder). It is not to be confused with the concepts "soldering ability" (see 3.3).
3.2
wettability
intrinsic property of the termination material to form an alloy with the solder
___________
Under preparation. Stage at the time of publication: IEC/FDIS 60194-1:2020.

– 10 – IEC 61189-5-601:2021 © IEC 2021
Note 1 to entry: Wettability depends on the base metal used to produce the termination or, in the case of a plated
termination, the condition and material used to plate the base metal.
3.3
soldering ability
ability of a specific combination of components to facilitate the formation of a proper solder joint
Note 1 to entry: See 3.2, wettability.
3.4
resistance to soldering heat
ability of the component to withstand the highest temperature in terms of temperature gradient,
peak temperature and duration of the soldering process, within the applicable temperature
range of the solder alloy
3.5
reflow soldering
joining of surfaces that have been tinned and/or have solder between them, placing them
together, heating them until the solder flows, and allowing the surface and the solder to cool in
the joined position
3.6
wetting
formation of an adherent coating of solder on a surface indicated by a small contact angle
3.7
dewetting
retraction of molten solder on a solid area that it has initially wetted
Note 1 to entry: In some cases, an extremely thin film of solder may remain. As the solder retracts, the contact
angle increases.
3.8
non-wetting
inability to form an adherent coating of solder on a surface indicated by a contact angle greater
than 90°
3.9
dissolution of printed-board land
process of dissolving metal, usually by introduction of chemicals
4 Grouping of soldering processes and related test severities
The melting temperatures of lead-free solder alloys selected for industrial processes are
significantly different from those for Sn-Pb solder alloy. Moreover, the melting temperatures of
lead-free solder alloys are different from each other but can be clustered in groups.
The groups of soldering processes indicated in Table 2 are given as a guideline to select the
severities for the wetting and resistance tests at a specified soldering heat.

Table 2 – Grouping of soldering processes and typical test severities – Overview
a
Process temperature group 1 2
Typical solder alloy group Sn-Pb Sn-Ag-Cu
Typical
process Reflow peak temperature 210 °C to 240 °C 235 °C to 250 °C
temperature
Test
Test property Reflow peak temperature/Duration
method
b
Solder joint initial Maximum profile
Reflow
235 °C / 20 s or more 245 °C / 30 s or more
quality "Soldering temperature

ability"
Minimum profile
215 °C / 10 s or less 235 °C / 10 s or less
temperature
Warpage 235 °C / 20 s or more 245 °C / 30 s or more
Resistance to soldering heat 235 °C / 20 s or more 245 °C / 30 s or more
Wetting and dewetting 215 °C / 10 s or less 235 °C / 10 s or less
Resistance to dissolution 235 °C / 20 s or more 245 °C / 30 s or more
Pull strength 235 °C / 20 s or more 245 °C / 30 s or more
Typical process temperatures for reflow soldering are the land temperatures in device area on printed boards.
The Sn-Ag-Cu alloy listed in this table represents compositions that are currently preferred for lead-free soldering

processes. However, other solder alloys when matching with the specified group should not be excluded.
a
Refer to each appropriate subclauses for the detailed test conditions.
b
Measured at the solder joint or land of printed boards.

5 Specimens
5.1 Devices
Device specimens for this test are specified in IEC 62137-3.
When the evaluation needs to be conducted, the device used for this test is a dummy device
within which the terminations are connected as shown in Figure 1.
When the evaluation for leadless termination type devices needs to be conducted on the
resistance device, the device resistance for the test is a low-resistance device [as shown in
Figure 1 b)]. The resistance of the low-resistance device should be 50 mΩ or less.

– 12 – IEC 61189-5-601:2021 © IEC 2021

a) Example of area array type packages

b) Example of leadless termination type devices
Figure 1 – Example of a test circuit for the electrical continuity test of a solder joint
The following Figure 2, Figure 3, Figure 4, Figure 5 and Figure 6 show the typical appearance
of each package type.
Figure 2 – Example of area array type packages

Figure 3 – Example of leaded type devices

Figure 4 – Example of leadless termination type devices

Figure 5 – Example of connector for card type devices

Figure 6 – Example of shielding metal components
5.2 Test substrate
The test substrate material shall be single or double-sided mounting with single-layer, double-
layer or multilayer printed boards for material structure used with product. Unless otherwise
specified in the product specification, the test substrate shall be as follows.
a) Test substrate material
Test substrate material shall be a single-sided printed board for general use, for example,
copper-clad epoxide woven fiberglass reinforced laminated sheets as specified in
IEC 61249-2-7 or IEC 61249-2-8. The thickness shall be (1,6 ± 0,2) mm including copper
foil. The copper foil thickness shall be (35 ± 10) µm.
b) Test substrate dimensions
The test substrate dimensions depend on the mounted package size and shape. However,
the test substrate dimensions shall be able to be fixed on the pull strength test equipment.
c) Land shape and land dimensions
Land shape and land dimensions should be the same specification as used for product
design. Land shape and land dimensions should be as specified in IEC 61188-5-8.
Moreover, the test substrate and the test package shall be designed in such a way that their
land pattern forms a daisy chain circuit after mounting for the electrical continuity
measurement.
d) Surface finish of land pattern
If specified in the product specification, the surface finish treatment (for land pattern of the
printed board) shall be the same as specified in the product specification.
EXAMPLE: organic solderability preservative (OSP) or electroless nickel immersion gold (ENIG) plating layer.
5.3 Solder paste
Solder paste is made of flux, finely divided particles of solder, and additives to promote wetting
and to control viscosity, tackiness, slumping, drying rate, etc. Unless otherwise specified in the
product specification, one of the solder alloys listed below (as specified in IEC 61190-1-3) shall
be used. The product specification shall specify details of the solder paste.
The major composition of the solder alloys are as follows:
a) 63 % mass fraction of Sn (tin) and 37 % mass fraction of Pb (lead);
b) from 3,0 % to 4,0 % mass fraction of Ag (silver), from 0,5 % to 1,0 % mass fraction of Cu
(copper) and the remainder of Sn (tin).
EXAMPLE: Sn-Ag-Cu ternary alloy such as Sn96,5Ag3Cu,5 alloy is used.

– 14 – IEC 61189-5-601:2021 © IEC 2021
Solder paste shall be properly stored in accordance with the product's specification.
5.4 Solder ball
The diameter and height of the solder ball used should be the following size a) and b) and the
shape should be as shown in Figure 7. The composition should be equivalent to the one
indicated in IEC 61190-1-3.
a)
D
≤1,5
d
b)
D
1,1≤ ≤ 2,2
H
a) Solder ball
b) Solder mask defined (SMD) c) Non solder mask defined (NSMD)
type land type land
Key
d Land opening diameter
D1 Solder ball diameter
D2 Solder ball diameter after solder ball assembling
H Solder ball height after solder ball assembling
Figure 7 – Recommended solder ball shape
6 Apparatus and equipment
6.1 Constant temperature and humidity testing equipment
The pre-conditioning oven shall be able to maintain the evaluation conditions specified in the
specimen’s product specification. The general requirements for the pre-conditioning oven are
specified in IEC 60068-2 (all parts).
The humidifier shall be able to maintain the evaluation temperature and humidity as specified
in the specimen’s product specification. The material of the oven should not react at high

temperature. The water used for the test should be purified or de-ionized water, with a resistivity
of 5 000 MΩm (0,5 MΩcm) or higher (conductivity of 2 µS/cm or less). The equipment should
perform the test in accordance with IEC 60068-2-78.
6.2 Device-mounting equipment
a) Stencil for screen printing
The stencil shall be suitable for permitting the application of solder paste for the device
types and sizes to be mounted.
Unless otherwise specified in the product specification, the stencil used should conform to
the design standard shown in Table 3.
Table 3 – Stencil design standard for devices
Terminal type Stencil thickness Aperture diameter
For device 80 µm to 150 µm Match with the land size specified for device

There are three processing methods for the stencil: the etching method, the additive method,
and the laser processing method. It is recommended to use the stencil made by the additive
method or by the laser processing method, whose solder paste printing characteristic is
superior as it allows for finer pitches to be created.
b) Solder paste applying equipment
1) Screen printing equipment
The screen-printing equipment shall be capable of solder printing as described in 7.4.1.
2) Other equipment
If a dispenser, inkjet printing equipment or solder transfer apparatus are used to apply solder
paste, they shall be able to apply the amount defined by the product specification.
c) Device-mounting equipment
The device-mounting equipment shall be capable of mounting the devices described in 7.4.2.
d) Reflow soldering equipment
The reflow soldering equipment shall be able to realize the reflow soldering temperature
profile specified in Clause 4. Examples of temperature profiles
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