EN 60749-20:2009

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Semiconductor devices - Mechanical and climatic test methods - Part 20: Resistance of
plastic encapsulated SMDs to the combined effect of moisture and soldering heat (IEC
60749-20:2008)
Halbleiterbauelemente - Mechanische und klimatische Prüfverfahren - Teil 20:
Beständigkeit kunststoffverkappter oberflächenmontierbarer Bauelemente (SMD)
gegenüber der kombinierten Beanspruchung von Feuchte und Lötwärme (IEC 60749-
20:2008)
Dispositifs à semiconducteurs - Méthodes d'essais mécaniques et climatiques - Partie
20: Résistance des CMS à boîtiers plastique à l'effet combiné de l'humidité et de la
chaleur de brasage (IEC 60749-20:2008)
Ta slovenski standard je istoveten z: EN 60749-20:2009
ICS:
31.080.01 Polprevodniški elementi Semiconductor devices in
(naprave) na splošno general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN 60749-20
NORME EUROPÉENNE
November 2009
EUROPÄISCHE NORM
ICS 31.080.01 Supersedes EN 60749-20:2003

English version
Semiconductor devices -
Mechanical and climatic test methods -
Part 20: Resistance of plastic encapsulated SMDs
to the combined effect of moisture and soldering heat
(IEC 60749-20:2008)
Dispositifs à semiconducteurs -  Halbleiterbauelemente -
Méthodes d'essais mécaniques Mechanische und klimatische
et climatiques - Prüfverfahren -
Partie 20: Résistance Teil 20: Beständigkeit kunststoffverkappter
des CMS à boîtiers plastique oberflächenmontierbarer Bauelemente
à l'effet combiné de l'humidité (SMD) gegenüber der kombinierten
et de la chaleur de brasage Beanspruchung von Feuchte
(CEI 60749-20:2008) und Lötwärme
(IEC 60749-20:2008)
This European Standard was approved by CENELEC on 2009-09-01. 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, 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

Central Secretariat: Avenue Marnix 17, B - 1000 Brussels

© 2009 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 60749-20:2009 E
Foreword
The text of document 47/1989/FDIS, future edition 2 of IEC 60749-20, prepared by IEC TC 47,
Semiconductor devices, was submitted to the IEC-CENELEC parallel vote and was approved by
CENELEC as EN 60749-20 on 2009-09-01.
This European Standard supersedes EN 60749-20:2003.
The main changes are as follows:
– to reconcile certain classifications of EN 60749-20 and those of IPC/JEDEC J-STD-020C;
– reference EN 60749-35 instead of Annex A of EN 60749-20:2003;
– update for lead-free solder;
– correct certain errors in EN 60749-20:2003.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement (dop) 2010-06-01
– latest date by which the national standards conflicting
with the EN have to be withdrawn (dow) 2012-09-01
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 60749-20:2008 was approved by CENELEC as a European
Standard without any modification.
__________
– 3 – EN 60749-20:2009
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 60068-2-20 2008 Environmental testing - EN 60068-2-20 2008
Part 2-20: Tests - Test T: Test methods for
solderability and resistance to soldering heat
of devices with leads
1) 2)
IEC 60749-3 - Semiconductor devices - Mechanical and EN 60749-3 2002
climatic test methods -
Part 3: External visual examination

1) 2)
IEC 60749-35 - Semiconductor devices - Mechanical and EN 60749-35 2006
climatic test methods -
Part 35: Acoustic microscopy for plastic
encapsulated electronic components

1)
Undated reference.
2)
Valid edition at date of issue.

IEC 60749-20
Edition 2.0 2008-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Semiconductor devices – Mechanical and climatic test methods –
Part 20: Resistance of plastic encapsulated SMDs to the combined effect of
moisture and soldering heat
Dispositifs à semiconducteurs – Méthodes d'essais mécaniques et climatiques –
Partie 20: Résistance des CMS à boîtier plastique à l'effet combiné de l'humidité
et de la chaleur de brasage
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
U
CODE PRIX
ICS 31.080.01 ISBN 2-8318-1019-8
– 2 – 60749-20 © IEC:2008
CONTENTS
FOREWORD.4
1 Scope.6
2 Normative references.6
3 General description.6
4 Test apparatus and materials.6
4.1 Humidity chamber.6
4.2 Reflow soldering apparatus.6
4.3 Holder .7
4.4 Wave-soldering apparatus .7
4.5 Solvent for vapour-phase reflow soldering.7
4.6 Flux.7
4.7 Solder .7
5 Procedure.7
5.1 Initial measurements .7
5.1.1 Visual inspection.7
5.1.2 Electrical measurement.8
5.1.3 Internal inspection by acoustic tomography .8
5.2 Drying.8
5.3 Moisture soak .8
5.3.1 General .8
5.3.2 Conditions for non-dry-packed SMDs .8
5.3.3 Moisture soak for dry-packed SMDs .8
5.4 Soldering heat .10
5.4.1 General .10
5.4.2 Method of heating by infrared convection or convection reflow
soldering.11
5.4.3 Method of heating by vapour-phase reflow soldering.12
5.4.4 Method of heating by wave-soldering.12
5.5 Recovery .13
5.6 Final measurements .14
5.6.1 Visual inspection.14
5.6.2 Electrical measurement.14
5.6.3 Internal inspection by acoustic tomography .14
6 Information to be given in the relevant specification.14
Annex A (informative) Details and descriptions of test method on resistance of plastic
encapsulated SMDs to the combined effect of moisture and soldering heat.16

Figure 1 – Method of measuring the temperature profile of a specimen.7
Figure 2 – Heating by wave-soldering .13
Figure A.1 – Process of moisture diffusion at 85 °C, 85 % RH.17
Figure A.2 – Definition of resin thickness and the first interface .17
Figure A.3 – Moisture soak time to saturation at 85 °C as a function of resin thickness .18
Figure A.4 – Temperature dependence of saturated moisture content of resin.18
Figure A.5 – Dependence of moisture content of resin at the first interface on resin
thickness under various soak conditions.19

60749-20 © IEC:2008 – 3 –
Figure A.6 – Dependence of moisture content of resin at the first interface on resin
thickness related to method A of moisture soak .20
Figure A.7 – Dependence of the moisture content of resin at the first interface on resin
thickness related to method B of moisture soak .21
Figure A.8 – Dependence of moisture content of resin at the first interface on resin
thickness related to condition B2 of method B of moisture soak .21
Figure A.9 – Temperature profile of infrared convection and convection reflow soldering
for Sn-Pb eutectic assembly.23
Figure A.10 – Temperature profile of infrared convection and convection reflow
soldering for lead-free assembly.23
Figure A.11 – Classification profile .25
Figure A.12 – Temperature profile of vapour-phase soldering (condition II-A).25
Figure A.13 – Immersion method into solder bath .26
Figure A.14 – Relation between the infrared convection reflow soldering and wave-
soldering.26
Figure A.15 – Temperature in the body of the SMD during wave-soldering .27

Table 1 – Moisture soak conditions for non-dry-packed SMDs .8
Table 2 – Moisture soak conditions for dry-packed SMDs (method A) .9
Table 3 – Moisture soak conditions for dry-packed SMDs (method B) .10
Table 4 – SnPb eutectic process – Classification reflow temperatures .11
Table 5 – Pb-free process – Classification reflow temperatures .12
Table 6 – Heating condition for vapour-phase soldering .12
Table 7 – Immersion conditions for wave-soldering.13
Table A.1 – Comparison of actual storage conditions and equivalent moisture soak

conditions before soldering heat.18
Table A.2 – Classification profiles.24

– 4 – 60749-20 © IEC:2008
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SEMICONDUCTOR DEVICES –
MECHANICAL AND CLIMATIC TEST METHODS –

Part 20: Resistance of plastic encapsulated SMDs to
the combined effect of moisture and soldering heat

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 addition to other activities, IEC publishes International Standards, Technical Specifications,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
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 60749-20 has been prepared by IEC technical committee 47:
Semiconductor devices.
This second edition cancels and replaces the first edition published in 2002 and constitutes a
technical revision. The main changes are as follows:
• to reconcile certain classifications of IEC 60749-20 and those of IPC/JEDEC J-STD-020C;
• reference IEC 60749-35 instead of Annex A of IEC 60749-20, Edition 1;
• update for lead-free solder;
• correct certain errors in the original Edition 1.

60749-20 © IEC:2008 – 5 –
The text of this standard is based on the following documents:
FDIS Report on voting
47/1989/FDIS 47/2003/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all the parts in the IEC 60749 series, under the general title Semiconductor devices –
Mechanical and climatic test methods, can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until the
maintenance result 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.
– 6 – 60749-20 © IEC:2008
SEMICONDUCTOR DEVICES –
MECHANICAL AND CLIMATIC TEST METHODS –

Part 20: Resistance of plastic encapsulated SMDs to
the combined effect of moisture and soldering heat

1 Scope
This part of IEC 60749 provides a means of assessing the resistance to soldering heat of
semiconductors packaged as plastic encapsulated surface mount devices (SMDs). This test is
destructive.
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 60068-2-20:2008, Environmental testing – Part 2-20: Tests – Test T: Test methods for
solderability and resistance to soldering heat of devices with leads
IEC 60749-3, Semiconductor devices – Mechanical and climatic test methods – Part 3: External
visual inspection
IEC 60749-35, Semiconductor devices – Mechanical and climatic test methods – Part 35:
Acoustic microscopy for plastic encapsulated electronic components
3 General description
Package cracking and electrical failure in plastic encapsulated SMDs can result when soldering
heat raises the vapour pressure of moisture which has been absorbed into SMDs during
storage. These problems are assessed. In this test method, SMDs are evaluated for heat
resistance after being soaked in an environment which simulates moisture being absorbed
while under storage in a warehouse or dry pack.
4 Test apparatus and materials
4.1 Humidity chamber
The humidity chamber shall provide an environment complying with the temperature and
relative humidity defined in 5.3.
4.2 Reflow soldering apparatus
The infrared convection, the convection and the vapour-phase reflow soldering apparatus shall
provide temperature profiles complying with the conditions of soldering heat defined in 5.4.2
and 5.4.3. The settings of the reflow soldering apparatus shall be adjusted by temperature
profiling of the top surface of the specimen while it is undergoing the soldering heat process,
measured as shown in Figure 1.

60749-20 © IEC:2008 – 7 –
Adhesive agent or thin tape
Thermocouple
Die
Lead pins
Resin
Holder
IEC  1746/01
NOTE The adhesive agent or thin tape should have good thermal conductivity.
Figure 1 – Method of measuring the temperature profile of a specimen
4.3 Holder
Unless otherwise detailed in the relevant specification, any board material, such as epoxy
fibreglass or polyimide, may be used for the holder. The specimen shall be placed on the
holder by the usual means and in a position as shown in Figure 1. If the position of the
specimen, as shown in Figure 1, necessitates changing the shape of terminations and results
in subsequent electrical measurement anomalies, a position that avoids changing the shape of
terminations may be chosen, and this shall be specified in the relevant specification.
4.4 Wave-soldering apparatus
The wave-soldering apparatus shall comply with conditions given in 5.4.4. Molten solder shall
usually be flowed.
4.5 Solvent for vapour-phase reflow soldering
Perfluorocarbon (perfluoroisobutylene) shall be used.
4.6 Flux
Unless otherwise detailed in the relevant specification, the flux shall consist of 25 % by weight
of colophony in 75 % by weight of isopropyl alcohol, both as specified in Annex B of IEC 60068-
2-20:2008.
4.7 Solder
Solder of composition as specified in Table 1 of IEC 60068-2-20:2008 shall be used.
5 Procedure
5.1 Initial measurements
5.1.1 Visual inspection
Visual inspection, as specified in IEC 60749-3, shall be performed before the test. Special
attention shall be paid to external cracks and swelling, which will be looked for under a
magnification of 40×.
– 8 – 60749-20 © IEC:2008
5.1.2 Electrical measurement
Electrical testing shall be performed as required by the relevant specification.
5.1.3 Internal inspection by acoustic tomography
Unless otherwise detailed in the relevant specification, internal cracks and delamination in the
specimen shall be inspected by acoustic tomography in accordance with IEC 60749-35.
5.2 Drying
Unless otherwise detailed in the relevant specification, the specimen shall be baked at 125 °C
± 5 °C for at least 24 h.
5.3 Moisture soak
5.3.1 General
Unless otherwise detailed in the relevant specification, moisture soak conditions shall be
selected on the basis of the packing method of the specimen (see A.1.1). If baking the
specimen before soldering is detailed in the relevant specification, the specimen shall be baked
instead of being subject to moisture soak.
5.3.2 Conditions for non-dry-packed SMDs
The moisture soak condition shall be selected from Table 1, in accordance with the permissible
limit of actual storage (see A.1.2.1).
Table 1 – Moisture soak conditions for non-dry-packed SMDs
Permissible limit on
Temperature Relative humidity Duration time
Condition
°C % h actual storage
A1 or B1
85 ± 2 85 ± 5 168 ± 24 <30 °C, 85 % RH
RH: Relative humidity
NOTE Conditions A1 and B1 indicate moisture soak for non-dry-packed SMDs under either method A or B.

5.3.3 Moisture soak for dry-packed SMDs
5.3.3.1 General
Moisture soak conditions for dry-packed SMDs may be used as specified in method A, Table 2,
or method B, Table 3. Moisture soak conditioning for dry-packed SMDs consists of two stages.
The first stage of conditioning is intended to simulate moisturizing SMDs before opening the
dry pack/dry cabinet. The second stage of conditioning is to simulate moisturizing SMDs during
storage after opening the dry pack for soldering (floor life). Moisture soak conditioning for dry-
packed SMDs shall be selected from method A or B. Method A shall be used when the relative
humidity in the dry pack or dry cabinet is specified by the manufacturer as being between 10 %
and 30 %. Method B shall be used when the relative humidity in the dry pack or dry cabinet is
specified by the manufacturer as being below 10 %.

60749-20 © IEC:2008 – 9 –
5.3.3.2 Method A
Unless otherwise detailed in the relevant specification, the first stage conditioning of A2, as
shown in Table 2, shall be performed. Subsequently, the second stage conditioning of A2, as
shown in Table 2, shall be performed within 4 h of finishing the first stage of conditioning (see
A.1.2.2).
The relative humidity of the first stage conditioning must be the same as the upper limit of the
relative humidity inside the moisture barrier bag. The relative humidity of the second stage
conditioning must be the same as the conditions of floor life.
Where required in the relevant specification, test conditions other than those of the moisture
barrier bag and floor life conditions may be specified in the moisture soak conditions of Table 2.
Table 2 – Moisture soak conditions for dry-packed SMDs (method A)
Permissible storage
Moisture soak conditions in the dry Condition of
Condition
conditions pack and the dry floor life
cabinet
A2 first-stage (85 ± 2) °C, (30 ± 5) % RH,
conditioning
<30 °C, 30 % RH, 1 year –
168 h
−0
A2 second-stage
(30 ± 2) °C, (70 ± 5) % RH,
conditioning
– <30 °C, 70 % RH, 168 h
168 h
−0
RH: Relative humidity
NOTE 1 The first stage of conditioning represents storage conditions in the dry pack and the dry cabinet, as well
as increasing relative humidity in the dry pack, by repacking the SMDs at the distributor's facility and the user's
inspection facility. When condition A2 is applied, the SMDs should be packed into a moisture-proof bag with IC
trays and desiccants within a few weeks of drying. They may then be subjected to multiple temporary openings of
the moisture-proof bag (for several hours at a time). Repack and inspection of SMDs are possible while the
humidity indicator in the dry pack indicates less than 30 % RH since SMDs will recover the initial condition of
absorbed moisture within a few days of repacking. In this case, the moisture content measurement of SMDs (see
Clause A.2) is not needed as a moisture control of the dry pack. A check of the moisture indicator is sufficient for
moisture control.
NOTE 2 When moisture soak of the first-stage conditioning does not result in saturation, the soak time is
extended to 336 h, because SMDs in a dry pack or dry cabinet will become saturated with moisture during long-term
storage. When moisture soak of the first stage of conditioning reaches saturation, the soak time is shortened.
5.3.3.3 Method B
The condition of moisture soak conditioning shall be selected from Table 3 in accordance with
the condition of the floor life detailed in the relevant specification (see A.1.2.3).

– 10 – 60749-20 © IEC:2008
Table 3 – Moisture soak conditions for dry-packed SMDs (method B)
Total conditions from baking
Condition Moisture soak conditions to dry packing and temporary Condition of
...