Printed boards - Part 20: Printed circuit boards for high-brightness LEDs

IEC 62326-20:2016 specifies the properties of the printed circuit board (hereafter described as PCB) for high-brightness LEDs. Many aspects of the PCB for high-brightness LEDs are identical with those of ordinary PCBs, therefore, some aspects of this standard also describe general aspects. This edition includes the following significant technical changes with respect to the previous edition:
a) this edition focuses on the technical content of the printed circuit board for high-brightness LEDs;
b) the figures related to the printed circuit board for high-brightness LEDs have been refined.

Cartes imprimées - Partie 20: Cartes de circuits imprimés destinées aux LED à haute luminosité

L'IEC 62326-20:2016 spécifie les propriétés des cartes de circuits imprimés (ci après dénommées PCB, Printed Circuit Board) destinées aux LED à haute luminosité. Les PCB destinées aux LED à haute luminosité partagent avec les PCB ordinaires de nombreux aspects. Certains aspects d'ordre général sont donc décrits dans la présente norme. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
a) la présente édition se concentre sur le contenu technique des cartes de circuits imprimés destinées aux diodes électroluminescentes (LED) à haute luminosité;
b) les figures relatives aux cartes de circuits imprimés destinées aux LED à haute luminosité ont été affinées.

General Information

Status
Published
Publication Date
02-Feb-2016
Current Stage
PPUB - Publication issued
Start Date
03-Feb-2016
Completion Date
03-Feb-2016
Ref Project

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IEC 62326-20
Edition 1.0 2016-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Printed boards –
Part 20: Printed circuit boards for high-brightness LEDs
Cartes imprimées –
Partie 20: Cartes de circuits imprimés destinées aux LED à haute luminosité
IEC 62326-20:2016-02(en-fr)
---------------------- Page: 1 ----------------------
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---------------------- Page: 2 ----------------------
IEC 62326-20
Edition 1.0 2016-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Printed boards –
Part 20: Printed circuit boards for high-brightness LEDs
Cartes imprimées –
Partie 20: Cartes de circuits imprimés destinées aux LED à haute luminosité
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 31.180 ISBN 978-2-8322-3152-4

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 62326-20:2016 © IEC 2016
CONTENTS

FOREWORD ......................................................................................................................... 6

1 Scope ............................................................................................................................ 8

2 Normative references..................................................................................................... 8

3 Terms, definitions and abbreviations .............................................................................. 8

3.1 Terms and definitions ............................................................................................ 8

3.2 Abbreviations ........................................................................................................ 8

4 Classification and class of the printed circuit board for high-brightness LEDs .................. 9

5 Design rules and allowance ......................................................................................... 10

5.1 Panel and board sizes ......................................................................................... 10

5.1.1 Board size ................................................................................................... 10

5.1.2 Allowance of dimensions .............................................................................. 11

5.1.3 Perforation and slit ....................................................................................... 11

5.1.4 V-cut ............................................................................................................ 12

5.2 Total board thickness .......................................................................................... 13

5.3 Holes .................................................................................................................. 14

5.3.1 Insertion holes and vias ............................................................................... 14

5.3.2 Datum hole .................................................................................................. 16

5.3.3 Assembly hole (a through-hole without wall plating) ...................................... 16

5.4 Conductor ........................................................................................................... 17

5.4.1 Width of conductor pattern and its allowance ................................................ 17

5.4.2 Distance between conductors and its allowance ............................................ 17

5.4.3 Thickness of the insulating layer ................................................................... 18

5.5 Printed contact .................................................................................................... 18

5.5.1 Allowance of the distance between the centers of two adjacent printed

contacts ....................................................................................................... 18

5.5.2 Allowance of the terminal width of printed contacts ....................................... 19

5.5.3 Shift of the center of printed contacts on front and back sides of a board ....... 19

5.6 Land pattern ....................................................................................................... 20

5.6.1 Allowance of the distance between the centers of two lands .......................... 20

5.6.2 Allowance of the width of a land ................................................................... 20

5.6.3 Land diameter and its allowance for BGA/CSP .............................................. 21

5.7 Fiducial mark and mark for component positioning ............................................... 22

5.7.1 Typical form and size of the fiducial mark ..................................................... 22

5.7.2 Dimensional allowance of fiducial mark and component positioning mark ...... 23

5.7.3 Position allowance of the component positioning mark .................................. 23

5.8 Interlayer connection – Copper plating ................................................................. 23

6 Quality ........................................................................................................................ 24

6.1 Gap between conductor and the wall of a component insertion hole or a via ......... 24

6.2 Positional deviation between conductor layers of a multilayer board ..................... 24

6.3 Minimum land width ............................................................................................. 24

6.4 Surface treatment ............................................................................................... 25

6.4.1 Gold plating for printed contact ..................................................................... 25

6.4.2 Other surface treatment ............................................................................... 26

6.5 Defects of solder resist ........................................................................................ 26

6.6 Symbol mark ....................................................................................................... 28

6.6.1 General ....................................................................................................... 28

---------------------- Page: 4 ----------------------
IEC 62326-20:2016 © IEC 2016 – 3 –

6.6.2 Conductor surface ........................................................................................ 28

6.6.3 Between conductors ..................................................................................... 28

6.6.4 Defects within insulating layers .................................................................... 29

6.6.5 Routing and drilling ...................................................................................... 30

6.6.6 Conductor pattern ........................................................................................ 30

6.7 Land ................................................................................................................... 30

6.8 Land of a land pattern ......................................................................................... 31

6.9 Defects in a land for BGA/CSP mounting ............................................................. 32

6.10 Printed contact .................................................................................................... 32

7 Performance and test methods ..................................................................................... 34

7.1 Resistance of conductors .................................................................................... 34

7.2 Current proof of conductor and plated through hole .............................................. 35

7.3 Observation of component mountings and vias .................................................... 36

7.3.1 Observation with standard conditions ........................................................... 36

7.3.2 Observation after thermal shock test ............................................................ 38

8 Marking, packaging and storage ................................................................................... 39

8.1 Marking on a product ........................................................................................... 39

8.2 Marking on the package ...................................................................................... 39

8.3 Packaging and storage ........................................................................................ 40

8.3.1 Packaging .................................................................................................... 40

8.3.2 Storage ........................................................................................................ 40

Annex A (informative) Classification and class of the PCB for high-brightness LEDs ............ 41

Bibliography ....................................................................................................................... 46

Figure 1 – Example of a classification and its application ..................................................... 10

Figure 2 – Board arrangement in a panel ............................................................................. 11

Figure 3 – Distances from the datum point to perforation and slit ......................................... 12

Figure 4 – Distance from the datum point to the V-cut .......................................................... 12

Figure 5 – Allowance of position off-set of V-cuts on front and back surfaces ....................... 13

Figure 6 – PWB board with symbol mark, solder resist, copper foil and plating ..................... 13

Figure 7 – Positions of component insertion holes ............................................................... 15

Figure 8 – Distance between the wall of a hole and the board edge ..................................... 15

Figure 9 – Wall of a hole and the minimum designed spacing to the inner conductor ........... 16

Figure 10 – Width of finished conductor ............................................................................... 17

Figure 11 – Distance between conductor and board edge .................................................... 18

Figure 12 – Thickness of the insulating layer ....................................................................... 18

Figure 13 – Distance between centers of terminals of printed contacts ................................. 19

Figure 14 – Terminal width of a printed contact ................................................................... 19

Figure 15 – Shift of the center of printed contacts on front and back sides of a board .......... 20

Figure 16 – Land pattern ..................................................................................................... 20

Figure 17 – Land width of a land pattern .............................................................................. 21

Figure 18 – Land diameter of BGA/CSP formed of a conductor only ..................................... 21

Figure 19 – Land diameter (d) of BGA/CSP formed at the opening of solder resist ............... 22

Figure 20 – Examples of fiducial mark and component positioning mark ............................... 23

Figure 21 – Minimum land width .......................................................................................... 25

---------------------- Page: 5 ----------------------
– 4 – IEC 62326-20:2016 © IEC 2016

Figure 22 – Exposure of conductor ...................................................................................... 26

Figure 23 – Minimum land with caused by the shift of solder resist ....................................... 27

Figure 24 – Overlap, smear and shift of solder resist ........................................................... 27

Figure 25 – Examples of smear or blur ................................................................................ 28

Figure 26 – Example of measling ........................................................................................ 29

Figure 27 – Examples of crazing ......................................................................................... 29

Figure 28 – Conductor nicks................................................................................................ 30

Figure 29 – Conductor residue ............................................................................................ 30

Figure 30 – Land ................................................................................................................ 31

Figure 31 – Defects in a land of a land pattern..................................................................... 31

Figure 32 – Defects in BGA/CSP mounting lands ................................................................. 32

Figure 33 – Areas to be checked for defects of a printed contact .......................................... 33

Figure 34 – Defects in a printed contact .............................................................................. 33

Figure 35 – Relations between resistance and width, thickness and temperature of a

conductor ........................................................................................................................... 35

Figure 36 – Relationship between current, conductor width and thickness and

temperature rise ................................................................................................................. 36

Figure 37 – Defect on a plating of a component hole ........................................................... 37

Figure 38 – Resin smear ..................................................................................................... 38

Figure 39 – Corner crack .................................................................................................... 38

Figure 40 – Barrel crack ...................................................................................................... 39

Figure 41 – Foil crack ......................................................................................................... 39

Figure A.1 – Relation between thermal conductive parameter and heat transfer

coefficient parameter .......................................................................................................... 42

Table 1 – Application and classification ................................................................................. 9

Table 2 – Panel dimensions ................................................................................................ 11

Table 3 – Allowance of dimensions ..................................................................................... 11

Table 4 – Allowance of the distances from the datum point to perforation and slit ................ 12

Table 5 – Allowance of the distance from the datum point to the center of the V-cut ............. 13

Table 6 – Total thickness and its allowance ......................................................................... 14

Table 7 – Allowance of holes for component insertion .......................................................... 14

Table 8 – Position allowance of component insertion holes .................................................. 15

Table 9 – Distance between the wall of a hole and board edge ............................................ 16

Table 10 – Minimum clearance between the wall of a hole and the inner layer

conductor ........................................................................................................................... 16

Table 11 – Allowance of conductor width ............................................................................. 17

Table 12 – Allowance of the distance between conductors ................................................... 18

Table 13 – Allowance of terminal width of a printed contact ................................................. 19

Table 14 – Allowance of terminal width of a printed contact ................................................. 20

Table 15 – Allowance of the width of a land of a land pattern ............................................... 21

Table 16 – Land diameter and its allowance for BGA/CSP ................................................... 22

Table 17 – Allowance of the land diameter (d) of BGA/CSP formed at the opening of

solder resist ........................................................................................................................ 22

---------------------- Page: 6 ----------------------
IEC 62326-20:2016 © IEC 2016 – 5 –
Table 18 – Shapes and sizes of typical fiducial marks and component positioning

marks ................................................................................................................................. 23

Table 19 – Minimum thickness of copper plating .................................................................. 23

Table 20 – Minimum thickness of copper plating .................................................................. 24

Table 21 – Minimum land width ........................................................................................... 27

Table 22 – Overlap, smear and shift of solder resist over a fool print .................................... 28

Table 23 – Allowance of the area of a defect, remaining width and protrusion of a land ....... 31

Table 24 – Defect of a land of a land pattern ....................................................................... 32

Table 25 – Defects in BGA/CSP mounting lands .................................................................. 32

Table 26 – Defects in a printed contact ............................................................................... 34

Table 27 – Specification and test methods of resistance of conductors ................................. 34

Table 28 – Specification and test methods of current proof .................................................. 35

Table 29 – Allowance in horizontal sectioning ...................................................................... 38

Table A.1 – Relation between thermal conductive parameter and heat transfer

coefficient parameter .......................................................................................................... 42

Table A.2 – Related test methods ........................................................................................ 43

---------------------- Page: 7 ----------------------
– 6 – IEC 62326-20:2016 © IEC 2016
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
PRINTED BOARDS –
Part 20: Printed circuit boards for high-brightness LEDs
FOREWORD

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patent rights. IEC shall not be held responsible for identifying any or all such patent rights.

International Standard IEC 62326-20 has been prepared by IEC technical committee 91:

Electronics assembly technology.

This first edition cancels and replaces the IEC/PAS 62326-20 published in 2011, and

constitutes a technical revision.

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

edition:

a) this edition focuses on the technical content of the printed circuit board for high-brightness

LEDs;

b) the figures related to the printed circuit board for high-brightness LEDs have been refined.

---------------------- Page: 8 ----------------------
IEC 62326-20:2016 © IEC 2016 – 7 –
The text of this standard is based on the following documents:
FDIS Report on voting
91/1311/FDIS 91/1330/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.

A list of all parts in the IEC 62326 series, published under the general title Printed boards,

can be found on the IEC website.

This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

The committee has decided that the contents of this publication will remain unchanged until

the stability date indicated on the IEC website 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.

IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates

that it contains colours which are considered to be useful for the correct

understanding of its contents. Users should therefore print this document using a

colour printer.
---------------------- Page: 9 ----------------------
– 8 – IEC 62326-20:2016 © IEC 2016
PRINTED BOARDS –
Part 20: Printed circuit boards for high-brightness LEDs
1 Scope

This part of IEC 62326 specifies the properties of the printed circuit board (hereafter

described as PCB) for high-brightness LEDs. Many aspects of the PCB for high-brightness

LEDs are identical with those of ordinary PCBs, therefore, some aspects of this standard also

describe general aspects.
2 Normative references
The following documents, in whole or in part, are normatively referenced
...

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