IEC TS 62647-23:2013

IEC/TS 62647-23 ®
Edition 1.0 2013-10
TECHNICAL
SPECIFICATION
colour
inside
Process management for avionics – Aerospace and defence electronic systems
containing lead-free solder –
Part 23: Rework and repair guidance to address the implications of lead-free
electronics and mixed assemblies

IEC/TS 62647-23:2013(E)
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IEC/TS 62647-23 ®
Edition 1.0 2013-10
TECHNICAL
SPECIFICATION
colour
inside
Process management for avionics – Aerospace and defence electronic systems

containing lead-free solder –
Part 23: Rework and repair guidance to address the implications of lead-free

electronics and mixed assemblies

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
X
ICS 03.100.50; 31.020; 49.060 ISBN 978-2-8322-1162-5

– 2 – TS 62647-23  IEC:2013(E)
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 8
2 Normative references . 8
3 Terms, definitions and abbreviations . 9
3.1 Terms and definitions . 9
3.2 Abbreviations . 14
4 Pb-free concerns . 16
4.1 General . 16
4.2 Reliability . 16
4.2.1 General . 16
4.2.2 Mixed metallurgy reliability. 16
4.3 Configuration management . 17
4.4 Risk management . 18
4.5 Tin whiskers . 18
4.6 Copper dissolution (erosion) . 18
5 Materials . 18
5.1 Solder . 18
5.1.1 General . 18
5.1.2 Solder alloys . 18
5.1.3 Solder forms . 19
5.2 Fluxes . 20
5.3 Piece parts . 20
5.3.1 General . 20
5.3.2 Termination finishes . 20
5.3.3 Area arrays (BGA, CSP, etc.) . 20
5.4 Printed circuit boards/printed wiring boards . 21
5.4.1 Laminate material . 21
5.4.2 Surface finish . 21
5.5 Conformal coatings . 21
6 Soldering equipment . 22
6.1 General . 22
6.2 Hand soldering equipment . 22
6.2.1 General hand soldering equipment considerations . 22
6.2.2 Tip selection . 22
6.2.3 Soldering iron tip life . 23
6.3 Fountain soldering . 24
6.4 Convective soldering equipment . 25
6.4.1 General . 25
6.4.2 Thermal profile issues. 25
7 General rework/repair considerations . 26
7.1 General . 26
7.2 Rework/repair procedure order of precedence . 26
7.3 Technician training . 27
7.4 Pb-free rework/repair considerations . 27
7.4.1 General . 27

TS 62647-23  IEC:2013(E) – 3 –
7.4.2 General process considerations . 27
7.4.3 Solder processing considerations . 28
7.4.4 Flux considerations . 28
8 Pre-rework/repair processes . 29
8.1 Alloy identification . 29
8.1.1 IPC/JEDEC J-STD-609A . 29
8.1.2 X-ray fluorescence (XRF) . 31
8.1.3 Pb swabs . 31
8.2 Piece part and CCA preparation . 31
8.2.1 General . 31
8.2.2 Piece part preparation . 31
8.2.3 CCA preparation . 32
9 Rework/repair processes . 32
9.1 General . 32
9.2 Conductive hand soldering . 32
9.3 Convective soldering process . 34
9.3.1 General . 34
9.3.2 Solder paste handling . 34
9.3.3 Paste printing . 34
9.3.4 Reflow process . 34
10 Post-rework/repair processes . 36
10.1 Cleaning . 36
10.2 Inspection . 36
10.3 Reapplication of conformal coating . 36
Annex A (informative) Termination finishes . 37
Annex B (informative) Tin whiskers . 39
B.1 Tin whisker growth mechanisms . 39
B.2 Tin whisker mitigation techniques. 39
B.3 Hot solder dip . 39
B.4 Conformal coatings . 39
B.5 Specification of piece part termination finish . 40
B.6 Under-platings/annealing . 40
B.7 Piece part lead pitch . 40
Bibliography . 44

Figure 1 – Soldering iron tip construction . 23
Figure 2 – Worn soldering iron tip . 23
Figure 3 – Copper dissolution . 24

Table 1 – Assembly and piece part marking methods . 30
Table A.1 – Piece-part terminal and BGA ball metallization solder process
compatibility risk (see IEC/TS 62647-22:2013) . 37
Table A.2 – BGA piece parts risk . 38
Table B.1 – Tin whisker information (see IEC/TS 62647-22:2013) . 41
Table B.2 – Piece part termination tin whisker risks (see IEC/TS 62647-22:2013) . 42

– 4 – TS 62647-23  IEC:2013(E)
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
PROCESS MANAGEMENT FOR AVIONICS –
AEROSPACE AND DEFENCE ELECTRONIC
SYSTEMS CONTAINING LEAD-FREE SOLDER –

Part 23: Rework and repair guidance to address the implications
of lead-free electronics and mixed assemblies

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,
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...