IEC 61760-1:2006

IEC 61760-1 ®
Edition 2.0 2006-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Surface mounting technology –
Part 1: Standard method for the specification of surface mounting components
(SMDs)
Technique du montage en surface –
Partie 1: Méthode de normalisation pour la spécification des composants
montés en surface (CMS)
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.

Droits de reproduction réservés. Sauf indication contraire, aucune partie de cette publication ne peut être reproduite
ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photocopie
et les microfilms, sans l'accord écrit de l'IEC ou du Comité national de l'IEC du pays du demandeur. Si vous avez des
questions sur le copyright de l'IEC ou si vous désirez obtenir des droits supplémentaires sur cette publication, utilisez
les coordonnées ci-après ou contactez le Comité national de l'IEC de votre pays de résidence.

IEC Central Office Tel.: +41 22 919 02 11
3, rue de Varembé Fax: +41 22 919 03 00
CH-1211 Geneva 20 info@iec.ch
Switzerland www.iec.ch
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.

About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigenda or an amendment might have been published.

IEC Catalogue - webstore.iec.ch/catalogue Electropedia - www.electropedia.org
The stand-alone application for consulting the entire The world's leading online dictionary of electronic and
bibliographical information on IEC International Standards, electrical terms containing more than 30 000 terms and
Technical Specifications, Technical Reports and other definitions in English and French, with equivalent terms in 14
documents. Available for PC, Mac OS, Android Tablets and additional languages. Also known as the International
iPad. Electrotechnical Vocabulary (IEV) online.

IEC publications search - www.iec.ch/searchpub IEC Glossary - std.iec.ch/glossary
The advanced search enables to find IEC publications by a More than 55 000 electrotechnical terminology entries in
variety of criteria (reference number, text, technical English and French extracted from the Terms and Definitions
committee,…). It also gives information on projects, replaced clause of IEC publications issued since 2002. Some entries
and withdrawn publications. have been collected from earlier publications of IEC TC 37,

77, 86 and CISPR.
IEC Just Published - webstore.iec.ch/justpublished
Stay up to date on all new IEC publications. Just Published IEC Customer Service Centre - webstore.iec.ch/csc
details all new publications released. Available online and If you wish to give us your feedback on this publication or
also once a month by email. need further assistance, please contact the Customer Service
Centre: csc@iec.ch.
A propos de l'IEC
La Commission Electrotechnique Internationale (IEC) est la première organisation mondiale qui élabore et publie des
Normes internationales pour tout ce qui a trait à l'électricité, à l'électronique et aux technologies apparentées.

A propos des publications IEC
Le contenu technique des publications IEC est constamment revu. Veuillez vous assurer que vous possédez l’édition la
plus récente, un corrigendum ou amendement peut avoir été publié.

Catalogue IEC - webstore.iec.ch/catalogue Electropedia - www.electropedia.org
Application autonome pour consulter tous les renseignements
Le premier dictionnaire en ligne de termes électroniques et
bibliographiques sur les Normes internationales,
électriques. Il contient plus de 30 000 termes et définitions en
Spécifications techniques, Rapports techniques et autres
anglais et en français, ainsi que les termes équivalents dans
documents de l'IEC. Disponible pour PC, Mac OS, tablettes
14 langues additionnelles. Egalement appelé Vocabulaire
Android et iPad.
Electrotechnique International (IEV) en ligne.

Recherche de publications IEC - www.iec.ch/searchpub
Glossaire IEC - std.iec.ch/glossary
Plus de 55 000 entrées terminologiques électrotechniques, en
La recherche avancée permet de trouver des publications IEC
en utilisant différents critères (numéro de référence, texte, anglais et en français, extraites des articles Termes et
comité d’études,…). Elle donne aussi des informations sur les Définitions des publications IEC parues depuis 2002. Plus
projets et les publications remplacées ou retirées. certaines entrées antérieures extraites des publications des

CE 37, 77, 86 et CISPR de l'IEC.
IEC Just Published - webstore.iec.ch/justpublished

Service Clients - webstore.iec.ch/csc
Restez informé sur les nouvelles publications IEC. Just
Published détaille les nouvelles publications parues. Si vous désirez nous donner des commentaires sur cette
Disponible en ligne et aussi une fois par mois par email. publication ou si vous avez des questions contactez-nous:
csc@iec.ch.
IEC 61760-1 ®
Edition 2.0 2006-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Surface mounting technology –
Part 1: Standard method for the specification of surface mounting components

(SMDs)
Technique du montage en surface –

Partie 1: Méthode de normalisation pour la spécification des composants

montés en surface (CMS)
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX U
ICS 31.240 ISBN 978-2-8322-1344-5

– 2 – 61760-1  IEC:2006
CONTENTS
FOREWORD . 4
INTRODUCTION . 6

1 Scope and object . 7
1.1 Scope . 7
1.2 Object . 7
2 Normative references. 7
3 Terms and definitions . 8
4 Requirements for component design and component specifications . 10
4.1 General requirement . 10
4.2 Packaging . 10
4.3 Labelling of product packaging . 10
4.4 Component marking . 11
4.5 Storage and transportation . 12
4.6 Component outline and design . 12
4.7 Mechanical stress . 16
4.8 Component reliability assurance . 16
4.9 Additional requirements for compatibility with lead-free soldering . 16
5 Specification of assembly process conditions . 16
5.1 General . 16
5.2 Securing the component on the substrate prior to soldering . 18
5.3 Mounting methods . 19
5.4 Cleaning (where applicable) . 20
5.5 Removal and/or replacement of SMDs . 21
6 Typical process conditions . 22
6.1 Soldering processes, temperature/time profiles . 22
6.2 Typical cleaning conditions for assemblies . 26
7 Requirements for components and component specifications related to suitability
with various mounting processes . 27
7.1 General . 27
7.2 Wettability . 27
7.3 Resistance to dissolution of metallization . 27
7.4 Resistance to soldering heat . 27
7.5 Resistance to cleaning solvent . 28
7.6 Soldering profiles . 28
7.7 Bonding strength test for the component glue interface test . 28

Bibliography . 30

Figure 1 – Example of a component with marked specific orientation put in tape and tray . 11
Figure 2 – Vacuum pipette, pick-up area and component compartment:
Example for a component with a flat surface . 13
Figure 3 – Coplanarity of terminals . 13
Figure 4 – Stable seating of component . 14
Figure 5 – Unstable seating of component . 14
Figure 6 – Terminals arranged peripherally in two rows . 14

61760-1  IEC:2006 – 3 –
Figure 7 – Good contrast to component body and surroundings . 14
Figure 8 – Component weight/pipette suction strength . 15
Figure 9 – Process steps for soldering . 17
Figure 10 – Process steps for gluing. 18
Figure 11 – SnPb Vapour phase soldering – Temperature/time profile
(terminal temperature) . 22
Figure 12 – Lead-free SnAgCu Vapour phase soldering – Temperature/time profile
(terminal temperature) . 23
Figure 13 – Infrared soldering, forced gas convection reflow soldering –
Temperature/time profile for SnPb solders . 24
Figure 14 – Infrared soldering, forced gas convection reflow soldering –
Temperature/time profile for lead-free SnAgCu solders . 25
Figure 15 – Double wave soldering for SnPb and lead-free SnAgCu solder –
Temperature/time profile (terminal temperature) . 26

Table 1 – Basic cleaning processes . 26

– 4 – 61760-1  IEC:2006
INTERNATIONAL ELECTROTECHNICAL COMMISSION
___________
SURFACE MOUNTING TECHNOLOGY –
Part 1: Standard method for the specification
of surface mounting components (SMDs)

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 61760-1 has been prepared by IEC technical committee 91: Surface
mounting technology.
This second edition cancels and replaces the first edition, published in 1998, and constitutes a
technical revision.
The main changes with regard to the previous edition concern:
− requirements related to leadfree soldering;
− extension of the scope to include also components mounted by gluing;
− direct reference to IEC 60068-2-58 for requirements on solderability and resistance to
soldering heat;
− classification into categories based on the component's ability to withstand resistance to
soldering heat has been deleted.

61760-1  IEC:2006 – 5 –
This bilingual version (2014-02) corresponds to the monolingual English version, published in
2006-04.
The text of this standard is based on the following documents:
FDIS Report on voting
91/577/FDIS 91/588/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.
The French version of this standard has not been voted upon.
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 – 61760-1  IEC:2006
INTRODUCTION
Specifications for electronic components have in the past been formulated for each component
family. The regulations for environmental tests have been selected from IEC 60068 and other
IEC and ISO publications. The overriding condition for this procedure was that all components,
once installed in a piece of equipment, had to satisfy certain criteria.
The introduction and increasing use of surface mounting components make it necessary to
extend the existing requirements to include those arising from processing during assembly.
Irrespective of the component family involved, all components on one and the same side of a
printed circuit board are exposed to the same mounting process (see flow charts in Clause 5).
Nevertheless there exists no harmonized standard that prescribes the content of a component
specification. It is the purpose of this standard to define the general requirements for
component specifications derived from the assembly processes. This is done in three steps.
In the first step general requirements for component specifications and component design
related to the handling and placement of the component on the substrate are given (Clause 4).
In the second step the definition of reference process conditions as representative of a group
of assembly conditions are given (Clauses 5 and 6).
In the third step the additional requirements resulting from these reference process conditions
are given (Clause 7).
Mixed technology boards, i.e. boards containing through-hole components and SMDs, require
additional consideration with respect to the through-hole components. These may be subject to
the same requirements as the SMDs. Persons responsible for drafting specifications for “non-
surface mounting components” wishing to include a statement on their ability to withstand
surface mounting conditions should use the classifications and tests set out in the present
standard.
61760-1  IEC:2006 – 7 –
SURFACE MOUNTING TECHNOLOGY –
Part 1: Standard method for the specification
of surface mounting components (SMDs)

1 Scope and object
1.1 Scope
This International Standard gives a reference set of process conditions and related test
conditions to be used when compiling component specifications of electronic components that
are intended for usage in surface mount technology.
1.2 Object
The object of this standard is to ensure that a wide variety of SMDs (passive and active) can be
subjected to the same placement and mounting processes during assembly. This standard
defines tests and requirements that need to be part of any SMD component general, sectional
or detail specification. In addition, this standard provides component users and manufacturers
with a reference set of typical process conditions used in surface mount technology.
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 60062, Marking codes for resistors and capacitors
IEC 60068 (all parts), Environmental testing
IEC 60068-2-21, Environmental testing – Part 2: Tests – Test U: Robustness of terminations and
integral mounting devices
IEC 60068-2-45:1980, Environmental testing – Part 2: Tests – Test XA and guidance: Immersion
in cleaning solvents
Amendment 1 (1993)
IEC 60068-2-58, Environmental testing – Part 2: Tests – Test Td: Test methods for solderability,
resistance to dissolution of metallization and to soldering heat of surface mounting devices
(SMDs)
IEC 60068-2-77, Environmental testing – Part 2: Tests – Test 77: Body strength and impact shock
IEC 60191-6:2004, Mechanical standardization of semiconductor devices – Part 6: General
rules for the preparation of outline drawings of surface mounted semiconductor device
packages
IEC 60194, Printed board design, manufacture and assembly – Terms and definitions
IEC 60286-3, Packaging of components for automatic handling – Part 3: Packaging of surface
mount components on continuous tapes

– 8 – 61760-1  IEC:2006
IEC 60286-4, Packaging of components for automatic handling – Part 4: Stick magazines for
electronic components encapsulated in packages of form E and G
IEC 60286-5, Packaging of components for automatic handling – Part 5: Matrix trays
IEC 60286-6, Packaging of components for automatic handling – Part 6: Bulk case packaging
for surface mounting components
IEC 60749 (all parts), Semiconductor devices – Mechanical and climatic test methods
IEC 61340-5-1, Electrostatics – Part 5-1: Protection of electronic devices from electrostatic
phenomena – General requirements
IEC 61340-5-3, Electrostatics – Part 5-3: Protection of electronic devices from electrostatic
phenomena – Test methods for packagings intended for electrostatic discharge sensitive
devices
IEC 61760-2, Surface mount technology – Part 2: Transportation and storage conditions of
surface mounting devices (SMD) – Application guide
IEC 62090, Product package labels for electronic components using bar code and two
dimensional symbologies
ISO 8601, Data elements and interchange formats – Information interchange – Representation
of dates and times
3 Terms and definitions
For the purposes of this document, the following definitions apply, as do those of IEC 60194.
NOTE Use of the term “chip” as for a surface mounting component is deprecated. Only the terms "SMD" or
"surface mounting component" should be used within IEC.
3.1
adhesive
substance such as glue or cement used to bond objects together
NOTE In surface mounting technology different gluing systems are used.
− Non conductive adhesive (only for mechanical connection)
− Electrical conductive adhesive (for electrical and mechanical connection)
− Thermal conductive adhesive (for thermal and mechanical connection)
− Combination of electrical and thermal conductive adhesive.
Most used adhesives are thermal curing systems but there are also UV-curing systems in use.
3.2
centring force
force required by the pick-up tooling to centre a surface mounting device in its proper location
on a substrate
3.3
coplanarity
distance in height between the lowest and highest leads when the component is in its seating
plane
61760-1  IEC:2006 – 9 –
3.4
dewetting
condition that results when molten solder coats a surface and then recedes to leave irregularly-
shaped mounds of solder that are separated by areas that are covered with a thin film of solder
and with the basis metal not exposed
3.5
dissolution of metallization
process of dissolving metal or a plated metal alloy, usually by introduction of chemicals. For the
purpose of this document the dissolution of metallization also includes dissolution by exposure
to molten solder
3.6
immersion attitude
positioning of an object when immersed in a solder bath
3.7
lead-free component
component where lead content in the materials is equal or less than 0,1 % by weight per
material used
3.8
Montreal protocol
agreement by industrialized nations, at a meeting held in Montreal, Canada, to eliminate
chlorofluorocarbons from all processes by 1995
3.9
pick-up force
dynamic force exerted on the body of a component – generally from above – and its seating
plane during the pick-up of the component (e.g. from a tape or tray); the maximum level is
normally taken into account
3.10
placement force
dynamic force exerted on the component body – generally from above – and its seating plane
NOTE This occurs during the period between the component’s first contact with the substrate (or the soldering
paste or adhesive etc.) and its coming to rest. The maximum level is normally taken into account.
3.11
resistance to soldering heat
ability of a component to withstand the effects of the heat generated by the soldering process
3.12
seating plane
surface on which a component rests
3.13
solderability
ability of a metal to be wetted by molten solder
3.14
solder meniscus
contour of a solder shape that is the result of the surface tension forces that take place during
wetting
– 10 – 61760-1  IEC:2006
3.15
stand-off
distance between seating plane of the component and the seating plane of the terminations
3.16
substrate
basic material, forming the support structure of an electronic circuit
3.17
surface mounting component
electronic component designed for mounting on to terminal pads or conducting tracks on the
surface of substrate
3.18
wetting
physical phenomenon in which surface tension of a liquid, usually when in contact with solids,
is reduced to the point where the liquid diffuses and makes intimate contact with the entire
substrate surface in the form of a thin layer
4 Requirements for component design and component specifications
4.1 General requirement
A component specification for SMDs shall, in addition to the requirements listed in 4.2 to 4.10
below, contain specifications of the relevant tests and requirements from Clause 7.
4.2 Packaging
Information about the packaging form including packaging dimensions and data on clearances
within the packaging shall be included in the component specification.
Component specifications shall require that, packaging for SMD applications in tapes, on reels,
in stick magazines, on tray, bulk case, or in bulk shall comply with the relevant specification of
the IEC 60286 series (IEC 60286-3, IEC 60286-4, IEC 60286-5, IEC 60286-6).
Components that need to be entered into ESD protected production environment shall be
packaged accordingly in line with IEC 61340-5-1 and IEC 61340-5-3.
Moisture sensitive components need special packaging in line with IEC 60749.
Components with specific orientation or polarity shall be placed in the packaging with a fixed
orientation (e.g. see Figure 1).
4.3 Labelling of product packaging

Labelling of the product packaging shall comply with IEC 62090.
According to IEC 62090 the product packaging shall include the following:
a) item identification (e.g. customer part number or manufacturer part number or both);
b) traceability identification (e.g. batch number or serial number);
c) quantity;
61760-1  IEC:2006 – 11 –
Additional to the requirements of IEC 62090, this standard prescribes that the product
packaging for moisture sensitive components shall include the following:
d) moisture sensitivity level (MSL) according to IEC 60749;
Additional to the requirements of IEC 62090, this standard recommends that the product
packaging should include the following:
e) date code (ISO 8601, and IEC 60062);
f) identification code for the manufacturer;
g) Description of the polarity of the component, if applicable.
.
PIN 1
Tray
PIN 1
IEC  463/06
Figure 1 – Example of a component with marked specific orientation
put in tape and tray
4.4 Component marking
4.4.1 Marking of multipin components
Pin 1 (see Figure 1) shall be clearly marked on a multipin component (e.g. SO-IC, QFP).
4.4.2 Marking of components with polarity
For components with polarity, the polarity of the component shall be clearly marked on the
component (e.g. for electrolytic capacitors).
4.4.3 Durability of component marking
Specifications shall require that the specified component marking shall remain legible after the
test specified in 7.5.2 has been performed. This test shall be performed after completion of the
relevant test for resistance to soldering heat or for solderability, as specified in the component
specification.
Direction
– 12 – 61760-1  IEC:2006
4.5 Storage and transportation
Component specifications shall refer to IEC 61760-2 for storage and transportation conditions.
The component specification shall contain information concerning the maximum period for
storage. Within this period the component shall comply with its specification.
4.6 Component outline and design
4.6.1 Drawing and specification
An inverted-plan view of the component showing all dimensions and tolerances of its body and
terminals shall be part of the component specification. The plan shall include reference to the
positioning of the component body and terminals on the mounting land pattern.
Where necessary (e.g. in the case of mechanically fixed components with an overall length of
more than 25 mm), the detail specification shall contain data on thermal expansion, at least
along the X and Y axes.
4.6.2 Pick-up area requirements
Design of the component shall take into account that it shall be possible to grip the component
by suction and transport it to the exact placement position on the substrate. It shall be possible
to create a vacuum strong enough to fix the component in its position under the pipette. During
the total transport process, which may include optical inspection, the component shall remain
exactly in its position under the pipette, until the component is placed.
The centre of the suction area should match the centre of gravity and the geometrical centre.
The opening of the pipette (Y), the dimension (L) of the component or its pick up area (X) and
the tolerances on the position of the component inside the compartment of packaging with
length dimension (A ) and width dimension (B ) shall match in such a way, that the vacuum
0 0
needed for pick up can be created. It shall be possible to apply the vacuum irrespective of the
component’s position in its compartment.
For further requirements concerning the position of the component inside the packaging, see
IEC 60286-3 for taping and IEC 60286-5 for matrix trays.
NOTE Dimension L may be the length or the width of the component, as applicable.
Requirement: X – Y > Z
Z = (Z + Z ) = (A – L)
1 2 0
Z = (Z + Z ) = (B – L)
1 2 0
61760-1  IEC:2006 – 13 –
Pipette
Y
Component compartment
X
Z Z
1 2
Component
L
IEC  464/06
A or B
0 0
Figure 2 – Vacuum pipette, pick-up area and component compartment:
Example for a component with a flat surface
4.6.3 Bottom surface requirements
In cases where the component is to be bonded to the substrate with adhesive, its lower surface
(except for the terminals) must be capable of retaining the applied adhesive.
The stand-off between the lower surface of bonded components and the seating plane shall be
specified. The detail specification shall state the maximum stand-off. Normally a value of
0,3 mm should not be exceeded.
For components which are fixed by an additional fixing adhesive or in case a cleaning process
is used the minimum stand-off should be included in the component specification, because with
use of the additional fixing adhesive all pins have to be inside the material for the electrical
connection (solder paste or conductive adhesive).
4.6.4 Requirements for terminals
4.6.4.1 Coplanarity
Detail specifications of multipin components intended for reflow soldering/ conductive gluing
shall state the coplanarity of the lower surfaces of all terminals in accordance with 3.5 of
IEC 60191-6:2004. The typical value of coplanarity needed for reflow soldering is 0,1 mm –
0,15 mm, but depends on the size of the component and the thickness of printed solder. The
components terminals shall be sufficiently coplanar to ensure that contact is made with the
solder on the solder surfaces after solder printing or with the conductive adhesive. Detail
specifications of two pin components for mounting with conductive adhesive shall state the
coplanarity of both terminals in relation to the bottom surface of the component.

IEC  465/06
Figure 3 – Coplanarity of terminals
4.6.4.2 Arrangement of terminals
The terminals shall be arranged in such a way that stable seating in the solder paste or glue is
ensured and tilting is avoided (see Figures 4, 5 and 6).

– 14 – 61760-1  IEC:2006
Solder paste
IEC  466/06
Figure 4 – Stable seating of component

IEC  467/06
Figure 5 – Unstable seating of component
NOTE The land pattern of the component and its contacts should be analysed by the placement machine. The
terminals should be preferably arranged peripherally or otherwise symmetrically. Asymmetrical arrangements of
terminals can cause problems, because the identification algorithms are not always capable of identifying
asymmetrical structures. For small sized components symmetrical terminals are needed to prevent tombstoning.

IEC  468/06
Figure 6 – Terminals arranged peripherally in two rows
4.6.4.3 Optical recognition
The optical contrast between the terminal bottom surface and the component bottom surface
shall be high enough to enable optical recognition of the position of the terminals, seen from
the bottom side. Preferably the terminal bottom surface should be reflecting (see Figure 7).

IEC  469/06
Figure 7 – Good contrast to component body and surroundings

61760-1  IEC:2006 – 15 –
4.6.4.4 Shape of the terminals
The shape of the contact shall comply with that defined in the component specification.
Flattened wires that should be round, are an example of a shape not complying with
specification.
4.6.4.5 Hardness of the terminals
The terminal shall be hard enough to ensure that its shape remains unchanged during
placement.
4.6.4.6 Wettable surface
When specified for double side reflow soldering the surface forces of the molten solder
affecting the wettable area of the component’s terminals, shall be at least twice as high as the
gravity force resulting from the weight of the component. This is to assure that the component
remains adhered to the substrate during the second run of reflow soldering.
4.6.4.7 Material content
For components intended for mounting by gluing information on the material content should be
provided. Details on composition, thickness and layer structure of the surfaces to be glued
should be given.
4.6.4.8 Cleanliness of the surface
For components intended for mounting by gluing information on the cleanliness of the surfaces
should be provided. The adhesion of an adhesive may be prevented by a thin surface layer of
organic materials, for example by a thin layer of silicon oil. Therefore it is important, that the
surface of the components/terminal is free of any residues. Therefore the cleanliness of the
surface has to be defined by analysis (for example by ESCA (electron scattering for chemical
analysis)) or by a gluing test.
4.6.5 Component height
The component height is limited by the length of the pipette and the space traversed between
pick-up and placement. A proper clearance is required by the length of the pipette and the
component height for the traverse from pick-up to placement.
The component height and the component department of packing shall be matched to each
other to enable the pipette to safely pick up the component. If standardized packaging
complying with the IEC 60286 series of standards is used, the component height shall relate to
the packing dimensions specified therein.
4.6.6 Component weight
), resulting from the weight and the acceleration forces of the component shall
The net force (F
g
not exceed one third of the gripping force (F ) of the pipette (see Figure 8).
S
F
s
F
g
IEC  470/06
Figure 8 – Component weight/pipette suction strength

– 16 – 61760-1  IEC:2006
4.7 Mechanical stress
Components need to withstand the stresses applied by placement machinery and bending of
the substrate. In order to ensure this, component specifications shall comply with the following
test and test methods: Specification performance shall be specified in line with the relevant
sectional or generic specification.
– pick-up/impact force: IEC 60068-2-77
– centring force: IEC 60068-2-77
– placement force: IEC 60068-2-77
– bending stress: IEC 60068-2-21.
Mechanical fixing aids (e.g. guide pins, detents) should be avoided as much as possible.
4.8 Component reliability assurance
Requirements and related test methods that define the long term performance of a component
shall be part of the component specification. Test methods shall be applied that use
components mounted on a substrate. Test methods shall be preferably selected from
IEC 60068 series.
The component specification shall state the operating temperature range. Derating may be
applied. The operating temperature range shall be in accordance with the long term perform-
ance of the component.
Reliability assurance for some components may require restrictions to the choice of soldering
process and its parameters. It should be noted that components may experience typically up to
three consecutive reflow soldering processes. When the allowed parametric and mechanical
changes in the resistance to soldering heat test are determined, this multiple soldering shall be
taken into consideration. The number of allowed reflow soldering steps shall be specified in the
detail specification.
4.9 Additional requirements for compatibility with lead-free soldering
In component specifications the compatibility of the terminations with the solder used shall be
defined. This is as important to lead-free terminations in connection with lead-free solders as it
is in connection with lead containing solders.
5 Specification of assembly process conditions
5.1 General
5.1.1 Mounting by soldering
The steps in a production process depend on the mounting method used. Figure 9 shows a
typical flow chart.
61760-1  IEC:2006 – 17 –
SMDs and printed
boards
Printed boards with solid
solder deposits (SSDs) and
coated with flux adhesive
Solder paste Adhesive
Placing of Placing of Placing of
components components components
Predrying Curing of
of paste adhesive
Reflow Wave
soldering soldering
Cleaning
(where applicable)
Testing
IEC  1 073/98
Figure 9 – Process steps for soldering

– 18 – 61760-1  IEC:2006
5.1.2 Mounting by gluing
The steps in a production process depend on the mounting method used. Figure 10 shows a
typical flow chart.
SMDs and
substrates
Application of adhesive
(screen printing, stencil printing
or dispensing)
Placing of
components
Curing of
adhesive
Cleaning
(where applicable)
Wire bonding
(where applicable)
Testing
IEC  471/06
Figure 10 – Process steps for gluing
5.2 Securing the component on the substrate prior to soldering
Components may be secured to the substrate prior to soldering by using either an adhesive or
by the applied solder paste.
Heat treatment is used to cure the adhesive, for example, 120 °C for 30 min in a batch
process, or 150 °C for 120 s in a continuous process.
The times and temperatures for predrying of the solder paste depend on the type of solder
paste used.
61760-1  IEC:2006 – 19 –
5.3 Mounting methods
Several methods can be used to mount components on to the substrate. The following list is
not exhaustive.
5.3.1 Reflow soldering
a) Vapour phase reflow
This involves soldering in saturated vapour and is also called condensation soldering. This
process can be used either as a batch system (with two vapour zones) or as a continuous
system with a single vapour zone. Both systems may also require preheating of the
assemblies to prevent thermal shock and other undesirable side-effects.
Typical temperature/time profiles for the full process are shown in Figure 11 for soldering
with lead containing SnPb solders and in Figure 12 for soldering with lead-free SnAgCu
solder. The specific equipment used has influence on the resulting profile, especially the
type of preheating and whether controlled vapour heating power is used or not.
b) Forced air convection reflow soldering
This is the dominating reflow soldering method in which most of the energy for heating the
assembly is derived from gas (air or inert gas or a mixture of both). A small proportion of
the energy may be derived from direct infrared radiation. There is no contact with the
assemblies during heating.
The following parameters influence the temperature of the component, leading to
temperature differences between different components on a substrate and between parts of
the components (e.g. between terminal and top surface of the component):
– time and thermal power input;
– component mass;
– component size;
– substrate size;
– package density and shadowing;
– wavelength spectrum of radiation source;
– absorption coefficient of surfaces;
– ratio of radiation to convection energy.
Warning: There is a tendency for small components to warm up more than the large ones
under the same process conditions and this may lead to exceeding the resistance to
soldering heat conditions.
Typical temperature/time profiles for the full process are shown in Figure 13 for soldering
with lead containing SnPb solders and in Figure 14 for soldering with lead-free SnAgCu
solder (see NOTE). The typical profile represents the terminal temperature of a mid size
component. The coldest terminal temperature on an assembled substrate shall be above
the lower process limit line to ensure good solder joints.
NOTE The experience with SnAgCu soldering is rapidly increasing at the time of writing of this standard.
Therefore changes in this typical profile can be expected.
The maximum temperature, measured on the top surface of a component shall not exceed
the upper process limit to avoid component damage by heat exceeding the component
resistance
...