Surface mounting technology - Part 3: Standard method for the specification of components for through-hole reflow (THR) soldering

IEC 61760-3:2021 gives a reference set of requirements, process conditions and related test conditions to be used when compiling specifications of electronic components that are intended for usage in through-hole reflow soldering technology.
The object of this document is to ensure that components with leads intended for through-hole reflow and surface mounting components can be subjected to the same placement and mounting processes. Hereto, this document defines test and requirements that need to be part of any component generic, sectional or detail specification, when through-hole reflow soldering is intended.
Furthermore, this document provides component users and manufacturers with a reference set of typical process conditions used in through-hole reflow soldering technology.
This edition includes the following significant technical changes with respect to the previous edition:
a) change position tolerance requirement (0,4 mm maximum to between 0,2 mm and 0,4 mm);
b) introduce through-hole vacant method as a solder paste supply method.

Technique du montage en surface - Partie 3: Méthode normalisée relative à la spécification des composants pour le brasage par refusion à trous traversants (THR, Through Hole Reflow)

L’IEC 61760-3:2021 fournit un référentiel d’exigences et définit les conditions de procédé ainsi que les conditions d’essai correspondantes à utiliser pour élaborer les spécifications des composants électroniques destinés à être employés avec la technique du brasage par refusion à trous traversants (THR).
L’objet du présent document est de s’assurer que les composants équipés de sorties destinées à la THR et les composants pour montage en surface peuvent être soumis aux mêmes procédés de placement et de montage. Ici, le présent document définit les essais et les exigences faisant nécessairement partie de toute spécification générique, intermédiaire ou particulière de composant, lorsqu’il s’agit de brasage par refusion à trous traversants.
De plus, le présent document fournit aux utilisateurs de composants et à leurs fabricants un référentiel des conditions de procédés typiques utilisées dans le cadre de la technologie du brasage par refusion à trous traversants.
Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
a) modification de l’exigence relative à la tolérance de position (0,4 mm au maximum et entre 0,2 mm et 0,4 mm);
b) introduction de la méthode du trou traversant vide comme méthode d’application de pâte à braser.

General Information

Status
Published
Publication Date
02-Feb-2021
Current Stage
PPUB - Publication issued
Completion Date
03-Feb-2021
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IEC 61760-3
Edition 2.0 2021-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Surface mounting technology –
Part 3: Standard method for the specification of components for through-hole
reflow (THR) soldering
Technique du montage en surface –
Partie 3: Méthode normalisée relative à la spécification des composants pour
le brasage par refusion à trous traversants (THR, Through Hole Reflow)
IEC 61760-3:2021-02(en-fr)
---------------------- Page: 1 ----------------------
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---------------------- Page: 2 ----------------------
IEC 61760-3
Edition 2.0 2021-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Surface mounting technology –
Part 3: Standard method for the specification of components for through-hole
reflow (THR) soldering
Technique du montage en surface –
Partie 3: Méthode normalisée relative à la spécification des composants pour
le brasage par refusion à trous traversants (THR, Through Hole Reflow)
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 31.190 ISBN 978-2-8322-9294-5

Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
---------------------- Page: 3 ----------------------
– 2 – IEC 61760-3:2021 © IEC 2021
CONTENTS

FOREWORD ........................................................................................................................... 4

1 Scope .............................................................................................................................. 6

2 Normative references ...................................................................................................... 6

3 Terms and definitions ...................................................................................................... 7

4 Requirements to component design and component specifications .................................. 9

4.1 General requirement ............................................................................................... 9

4.2 Packaging ............................................................................................................... 9

4.3 Labelling of component packaging ........................................................................ 10

4.4 Component marking .............................................................................................. 10

4.5 Storage and transportation .................................................................................... 10

4.6 Component outline and design .............................................................................. 10

4.6.1 Drawing and specification .............................................................................. 10

4.6.2 Requirement of pick-up area .......................................................................... 11

4.6.3 Component tilt ............................................................................................... 13

4.6.4 Bottom surface requirements ......................................................................... 13

4.6.5 Terminal requirements ................................................................................... 14

4.6.6 Optical recognition ......................................................................................... 19

4.6.7 Component height ......................................................................................... 19

4.6.8 Component mass ........................................................................................... 20

4.7 Mechanical stress ................................................................................................. 20

4.8 Component reliability ............................................................................................ 20

4.9 Additional requirements for compatibility with lead-free soldering .......................... 20

5 Typical process conditions for THR soldering process ................................................... 20

5.1 Mounting by through-hole reflow soldering ............................................................ 20

5.2 Solder paste supply .............................................................................................. 21

5.3 Component insertion ............................................................................................. 22

5.4 Reflow soldering methods (recommended) ............................................................ 22

5.5 Cleaning ............................................................................................................... 23

5.5.1 General ......................................................................................................... 23

5.5.2 Cleaning medium and cleaning method .......................................................... 23

5.5.3 Cleaning process conditions .......................................................................... 23

5.6 Removal and/or replacement of soldered components .......................................... 24

6 Relevant tests and requirements for components and component specifications for

THR soldering process .................................................................................................. 24

6.1 General ................................................................................................................. 24

6.2 Wettability ............................................................................................................. 25

6.3 Dewetting ............................................................................................................. 25

6.4 Resistance to soldering heat ................................................................................. 25

6.5 Resistance to cleaning solvent .............................................................................. 25

6.5.1 General ......................................................................................................... 25

6.5.2 Solvent resistance of component ................................................................... 26

6.5.3 Solvent resistance of marking ........................................................................ 26

6.6 Soldering profile .................................................................................................... 26

6.7 Moisture sensitivity level ....................................................................................... 26

7 Quality criteria for THR soldering ................................................................................... 26

Annex A (informative) Flux creeping-up and solder wicking .................................................. 27

---------------------- Page: 4 ----------------------
IEC 61760-3:2021 © IEC 2021 – 3 –

Bibliography .......................................................................................................................... 28

Figure 1 – Example of a component with marked specific orientation put in tape

and tray .................................................................................................................................. 9

Figure 2 – Example of components in a tape ......................................................................... 10

Figure 3 – Pick-up area ......................................................................................................... 12

Figure 4 – Chuck jaw ............................................................................................................ 12

Figure 5 – Component side flat surface ................................................................................. 13

Figure 6 – Component top flat surface .................................................................................. 13

Figure 7 – Clearance ............................................................................................................ 14

Figure 8 – Stand-off height ................................................................................................... 14

Figure 9 – Terminal length and protrusion length .................................................................. 15

Figure 10 – Terminal position tolerance 0,2 mm .................................................................... 16

Figure 11 – Terminal position tolerance 0,4 mm .................................................................... 17

Figure 12 – Terminal shape .................................................................................................. 18

Figure 13 – Solder wetting .................................................................................................... 19

Figure 14 – Typical soldering process steps.......................................................................... 21

Figure 15 – Solder paste supply ............................................................................................ 22

Figure A.1 – Example of the flux creeping-up ........................................................................ 27

Figure A.2 – Example of the solder wicking ........................................................................... 27

Table 1 – Typical cleaning conditions.................................................................................... 24

---------------------- Page: 5 ----------------------
– 4 – IEC 61760-3:2021 © IEC 2021
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SURFACE MOUNTING TECHNOLOGY –
Part 3: Standard method for the specification of
components for through-hole reflow (THR) soldering
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 itself does not provide any attestation of conformity. Independent certification bodies provide conformity

assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any

services carried out by independent certification bodies.

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.

IEC 61760-3 has been prepared by IEC technical committee 91: Electronics assembly

technology. It is an International Standard.

This second edition cancels and replaces the first edition published in 2010. This edition

constitutes a technical revision.

This edition includes the following significant technical changes with respect to the previous

edition:

a) change position tolerance requirement (0,4 mm maximum to between 0,2 mm and 0,4 mm);

b) introduce through-hole vacant method as a solder paste supply method.
---------------------- Page: 6 ----------------------
IEC 61760-3:2021 © IEC 2021 – 5 –
The text of this International Standard is based on the following documents:
Draft Report on voting
91/1684/FDIS 91/1702/RVD

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 61760 series, published under the general title Surface mounting

technology, 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 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.
---------------------- Page: 7 ----------------------
– 6 – IEC 61760-3:2021 © IEC 2021
SURFACE MOUNTING TECHNOLOGY –
Part 3: Standard method for the specification of
components for through-hole reflow (THR) soldering
1 Scope

This part of IEC 61760 gives a reference set of requirements, process conditions and related

test conditions to be used when compiling specifications of electronic components that are

intended for usage in through-hole reflow soldering technology.

The object of this document is to ensure that components with leads intended for through-hole

reflow and surface mounting components can be subjected to the same placement and

mounting processes. Hereto, this document defines test and requirements that need to be part

of any component generic, sectional or detail specification, when through-hole reflow soldering

is intended.

Furthermore, this document provides component users and manufacturers with a reference set

of typical process conditions used in through-hole reflow soldering technology.
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 (all parts), Environmental testing

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 60068-2-21, Environmental testing – Part 2-21: Tests – Test U: Robustness of terminations

and integral mounting devices

IEC 60068-2-45:1980, Basic environmental testing procedures – Part 2-45: Tests – Test XA

and guidance: Immersion in cleaning solvents
IEC 60068-2-45:1980/AMD1:1993

IEC 60068-2-58, Environmental testing – Part 2-58: Tests – Test Td: Test methods for

solderability, resistance to dissolution of metallization and to soldering heat of surface mounting

devices (SMD)
, Environmental testing – Part 2-77: Tests – Test 77: Body strength and impact
IEC 60068-2-77
shock

IEC 60194-1, Printed boards design, manufacture and assembly – Vocabulary – Part 1:

Common usage in printed board and electronic assembly technologies
___________
To be integrated into the seventh edition of IEC 60068-2-21.
Stage at the time of publication: IEC/AFDIS 60068-2-21:2021.
---------------------- Page: 8 ----------------------
IEC 61760-3:2021 © IEC 2021 – 7 –
IEC 60286 (all parts), Packaging of components for automatic handling

IEC 60286-3, Packaging of components for automatic handling – Part 3: Packaging of surface

mount components on continuous tapes

IEC 60286-4, Packaging of components for automatic handling – Part 4: Stick magazines for

electronic components encapsulated in packages of different forms

IEC 60286-5, Packaging of components for automatic handling – Part 5: Matrix trays

IEC 60749-20, Semiconductor devices – Mechanical and climatic test methods – Part 20:

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

IEC 61188-6-4, Printed boards and printed board assemblies – Design and use – Part 6-4: Land

pattern design – Generic requirements for dimensional drawings of surface mounted

components (SMD) from the viewpoint of land pattern design

IEC 61191-3, Printed board assemblies – Part 3: Sectional specification – Requirements for

through-hole mount soldered assemblies
IEC 61760-1:2020, Surface mounting technology – Part 1: Standard method for the
specification of surface mounting components (SMDs)

IEC 61760-2, Surface mounting technology – Part 2: Transportation and storage conditions of

surface mounting devices (SMD) – Application guide

IEC 61760-4:2015, Surface mounting technology – Part 4: Classification, packaging, labelling

and handling of moisture sensitive devices

IPC/JEDEC J-STD-020, Moisture/Reflow Sensitivity Classification for Non-hermetic Solid State

Surface Mount Devices
IPC-A-610G, Acceptability of Electronic Assemblies
3 Terms and definitions

For the purposes of this document, the terms and definitions given in IEC 60194-1 and the

following 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 https://www.iso.org/obp
3.1
through-hole reflow
THR

reflow soldering process for electronic component terminals inserted into the through-hole of

the circuit board
3.2
THR components
through-hole reflow components

electronic components with leads which are intended to be subject to through-hole reflow

soldering
---------------------- Page: 9 ----------------------
– 8 – IEC 61760-3:2021 © IEC 2021
3.3
vacuum nozzle
pipette
type of tooling for component to pick-up and place the component with vacuum
3.4
chuck
gripper
type of tooling for component transfer
3.5
chucking
gripping
motion of the chuck (3.4) to hold the components
3.6
pick-up area

component surface area for vacuum suction or chucking to transfer within pick and place

machine
3.7
cavity of packaging
depression area to place component in taping or tray
3.8
stand-off

protrusion(s) from the component body which are used to make a space between the component

body and the seating plane
Note 1 to entry: Stand-off prevents the component touching the solder paste.
3.9
clearance

space to avoid contact between component body and solder paste and to ensure sufficient heat

transfer to soldering regions
3.10
auxiliary terminal
protrusion which has no electrical function inserted into a circuit board
3.11
stencil
stencil foil

thin sheet of material containing openings to reflect a specific pattern, designed to transfer

solder paste like material to a circuit board for the purpose of component attachment

[SOURCE: IEC 60194-1:2021, 3.19.187, modified – The words " paste-like material " have been

replaced by "solder paste like material" and “substrate” has been replaced by “circuit board”.]

3.12
A side
circuit board surface to which THR components (3.2) are to be mounted
3.13
B side
reverse surface of A side (3.12)
---------------------- Page: 10 ----------------------
IEC 61760-3:2021 © IEC 2021 – 9 –
3.14
solder wicking
capillary movement of solder between metal surfaces, such as strands of wire
[SOURCE: IEC 60194-1:2021, 3.19.125]
4 Requirements to component design and component specifications
4.1 General requirement

The component specification for THR components (hereinafter, referred to as component

specification) shall specify the requirements specified in 4.2 through 4.9 and Clause 6.

4.2 Packaging

Packaging for THR components shall be in accordance with IEC 60286-3, IEC 60286-4 and

IEC 60286-5.
The component specification shall specify the following:
– Protection of THR components during transportation and storage;

– Moisture absorption control; if needed, follow the moisture sensitivity level (MSL) according

to IEC 61760-4, IEC 60749-20 or IPC/JEDEC J-STD-020 (see 6.7);
– Polarity or pin 1 indication (see Figure 1);
– Orientation of the component in the packaging (see Figure 2).
Figure 1 – Example of a component with marked
specific orientation put in tape and tray
---------------------- Page: 11 ----------------------
– 10 – IEC 61760-3:2021 © IEC 2021
Figure 2 – Example of components in a tape
4.3 Labelling of component packaging
Labelling of the component packaging should comply with IEC 62090.
NOTE The following items are particularly important.

– item identification (e.g. customer part number or manufacturer part number or both);

– quantity;
– traceability identification (e.g. batch number or serial number).
4.4 Component marking
The marking on the component shall be specified in the component specification.
4.5 Storage and transportation

Component specification shall refer to storage and transportation conditions of IEC 61760-2.

4.6 Component outline and design
4.6.1 Drawing and specification

Drawings, including bottom-view, top-view and side-view drawings, of the component showing

all dimensions and tolerances of its body and terminals shall be part of the component

specification. The drawing shall include reference to the positioning of the component body and

terminals on the mounting land pattern. If conductive surfaces are not planar, their three-

dimensional geometry shall be clearly specified with the relevant tolerances.

In any 2D drawing or 3D data, conductive parts/surfaces and insulating parts/surfaces shall be

clearly distinguished, at least for bottom and sides of components, as well as for movable parts.

This requirement applies both to the disassembled and the assembled condition for parts

requiring a final assembly step after mounting on a substrate (e.g. if a connector contains

spring-loaded retainers, which change their position/angle upon mating). The locations and

dimensions of conductive parts/surfaces shall be specified even if they are not intended for

establishing a contact with the mounting surface, e.g. punched or sawn surfaces consisting of

unplated leadframe resulting from component singulation for molded semiconductor packages.

---------------------- Page: 12 ----------------------
IEC 61760-3:2021 © IEC 2021 – 11 –

Component drawing and component specification shall specify in particular the following

information:
– Dimensions and tolerances according to 4.6.4, 4.6.5.1 and 4.6.5.2;

– Dimensional drawings of footprint design. The generic requirements for dimensional

drawings of SMDs from viewpoint of land-pattern design as specified in IEC 61188-6-4 shall

be adopted for surface-mount devices;
– Locations of metal parts which contact to the circuit board surface.

The manufacturer of a THR component shall consider that the design and material selection

can lead to a possible expansion or deformation of the component in the reflow process. The

manufacturer shall provide an appropriate recommendation for mounting including a footprint

recommendation.
4.6.2 Requirement of pick-up area
4.6.2.1
...

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