1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationSemiconductor devices Mechanical and climatic testmethods Part 20: Resistance of plastic encapsulated SMDs to the combined effect of moisture andsoldering heatBS EN 60749-20:2009
2、National forewordThis British Standard is the UK implementation of EN 60749-20:2009. It isidentical to IEC 60749-20:2008. It supersedes BS EN 60749-20:2003 which iswithdrawn.The UK participation in its preparation was entrusted to Technical CommitteeEPL/47, Semiconductors.A list of organizations rep
3、resented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisions of acontract. Users are responsible for its correct application. BSI 2010ISBN 978 0 580 59478 6ICS 31.080.01Compliance with a British Standard cannot confer
4、 immunity fromlegal obligations.This British Standard was published under the authority of the StandardsPolicy and Strategy Committee on 31 January 2010Amendments issued since publicationAmd. No. Date Text affectedBRITISH STANDARDBS EN 60749-20:2009EUROPEAN STANDARD EN 60749-20 NORME EUROPENNE EUROP
5、ISCHE NORM November 2009 CENELEC European Committee for Electrotechnical Standardization Comit Europen de Normalisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: Avenue Marnix 17, B - 1000 Brussels 2009 CENELEC - All rights of exploitation in any form and
6、 by any means reserved worldwide for CENELEC members. Ref. No. EN 60749-20:2009 E ICS 31.080.01 Supersedes EN 60749-20:2003English version Semiconductor devices - Mechanical and climatic test methods - Part 20: Resistance of plastic encapsulated SMDs to the combined effect of moisture and soldering
7、heat (IEC 60749-20:2008) Dispositifs semiconducteurs - Mthodes dessais mcaniques et climatiques - Partie 20: Rsistance des CMS botiers plastique leffet combin de lhumidit et de la chaleur de brasage (CEI 60749-20:2008) Halbleiterbauelemente - Mechanische und klimatische Prfverfahren - Teil 20: Bestn
8、digkeit kunststoffverkappter oberflchenmontierbarer Bauelemente (SMD) gegenber der kombinierten Beanspruchung von Feuchte und Ltwrme (IEC 60749-20:2008) This European Standard was approved by CENELEC on 2009-09-01. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which s
9、tipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CENELEC member. This European Sta
10、ndard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the Central Secretariat has the same status as the official versions. CENELEC members are the nati
11、onal electrotechnical committees of Austria, Belgium, Bulgaria, Cyprus, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Swede
12、n, Switzerland and the United Kingdom. BS EN 60749-20:2009EN 60749-20:2009 2 Foreword The text of document 47/1989/FDIS, future edition 2 of IEC 60749-20, prepared by IEC TC 47, Semiconductor devices, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as EN 60749-20 on 2009-0
13、9-01. This European Standard supersedes EN 60749-20:2003. The main changes are as follows: to reconcile certain classifications of EN 60749-20 and those of IPC/JEDEC J-STD-020C; reference EN 60749-35 instead of Annex A of EN 60749-20:2003; update for lead-free solder; correct certain errors in EN 60
14、749-20:2003. The following dates were fixed: latest date by which the EN has to be implemented at national level by publication of an identical national standard or by endorsement (dop) 2010-06-01 latest date by which the national standards conflicting with the EN have to be withdrawn (dow) 2012-09-
15、01 Annex ZA has been added by CENELEC. _ Endorsement notice The text of the International Standard IEC 60749-20:2008 was approved by CENELEC as a European Standard without any modification. _ BS EN 60749-20:2009 3 EN 60749-20:2009 Annex ZA (normative) Normative references to international publicatio
16、ns with their corresponding European publications The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
17、 NOTE When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD applies. Publication Year Title EN/HD Year IEC 60068-2-20 2008 Environmental testing - Part 2-20: Tests - Test T: Test methods for solderability and resistance to soldering heat
18、of devices with leads EN 60068-2-20 2008 IEC 60749-3 - 1)Semiconductor devices - Mechanical and climatic test methods - Part 3: External visual examination EN 60749-3 2002 2)IEC 60749-35 - 1)Semiconductor devices - Mechanical and climatic test methods - Part 35: Acoustic microscopy for plastic encap
19、sulated electronic components EN 60749-35 2006 2)1)Undated reference. 2)Valid edition at date of issue. BS EN 60749-20:2009 2 60749-20 IEC:2008 CONTENTS 1 Scope.6 2 Normative references6 3 General description.6 4 Test apparatus and materials6 4.1 Humidity chamber6 4.2 Reflow soldering apparatus6 4.3
20、 Holder .7 4.4 Wave-soldering apparatus .7 4.5 Solvent for vapour-phase reflow soldering7 4.6 Flux.7 4.7 Solder .7 5 Procedure.7 5.1 Initial measurements .7 5.1.1 Visual inspection7 5.1.2 Electrical measurement8 5.1.3 Internal inspection by acoustic tomography 8 5.2 Drying8 5.3 Moisture soak8 5.3.1
21、General .8 5.3.2 Conditions for non-dry-packed SMDs .8 5.3.3 Moisture soak for dry-packed SMDs.8 5.4 Soldering heat .10 5.4.1 General .10 5.4.2 Method of heating by infrared convection or convection reflow soldering11 5.4.3 Method of heating by vapour-phase reflow soldering.12 5.4.4 Method of heatin
22、g by wave-soldering12 5.5 Recovery.13 5.6 Final measurements 14 5.6.1 Visual inspection14 5.6.2 Electrical measurement14 5.6.3 Internal inspection by acoustic tomography 14 6 Information to be given in the relevant specification.14 Annex A (informative) Details and descriptions of test method on res
23、istance of plastic encapsulated SMDs to the combined effect of moisture and soldering heat16 Figure 1 Method of measuring the temperature profile of a specimen7 Figure 2 Heating by wave-soldering 13 Figure A.1 Process of moisture diffusion at 85 C, 85 % RH17 Figure A.2 Definition of resin thickness
24、and the first interface .17 Figure A.3 Moisture soak time to saturation at 85 C as a function of resin thickness 18 Figure A.4 Temperature dependence of saturated moisture content of resin18 Figure A.5 Dependence of moisture content of resin at the first interface on resin thickness under various so
25、ak conditions19 BS EN 60749-20:200960749-20 IEC:2008 3 Figure A.6 Dependence of moisture content of resin at the first interface on resin thickness related to method A of moisture soak.20 Figure A.7 Dependence of the moisture content of resin at the first interface on resin thickness related to meth
26、od B of moisture soak.21 Figure A.8 Dependence of moisture content of resin at the first interface on resin thickness related to condition B2 of method B of moisture soak .21 Figure A.9 Temperature profile of infrared convection and convection reflow soldering for Sn-Pb eutectic assembly23 Figure A.
27、10 Temperature profile of infrared convection and convection reflow soldering for lead-free assembly23 Figure A.11 Classification profile 25 Figure A.12 Temperature profile of vapour-phase soldering (condition II-A).25 Figure A.13 Immersion method into solder bath 26 Figure A.14 Relation between the
28、 infrared convection reflow soldering and wave-soldering.26 Figure A.15 Temperature in the body of the SMD during wave-soldering .27 Table 1 Moisture soak conditions for non-dry-packed SMDs .8 Table 2 Moisture soak conditions for dry-packed SMDs (method A) 9 Table 3 Moisture soak conditions for dry-
29、packed SMDs (method B) 10 Table 4 SnPb eutectic process Classification reflow temperatures .11 Table 5 Pb-free process Classification reflow temperatures .12 Table 6 Heating condition for vapour-phase soldering.12 Table 7 Immersion conditions for wave-soldering13 Table A.1 Comparison of actual stora
30、ge conditions and equivalent moisture soak conditions before soldering heat18 Table A.2 Classification profiles24 BS EN 60749-20:2009 6 60749-20 IEC:2008 SEMICONDUCTOR DEVICES MECHANICAL AND CLIMATIC TEST METHODS Part 20: Resistance of plastic encapsulated SMDs to the combined effect of moisture and
31、 soldering heat 1 Scope This part of IEC 60749 provides a means of assessing the resistance to soldering heat of semiconductors packaged as plastic encapsulated surface mount devices (SMDs). This test is destructive. 2 Normative references The following referenced documents are indispensable for the
32、 application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IEC 60068-2-20:2008, Environmental testing Part 2-20: Tests Test T: Test methods for solderability and resist
33、ance to soldering heat of devices with leads IEC 60749-3, Semiconductor devices Mechanical and climatic test methods Part 3: External visual inspection IEC 60749-35, Semiconductor devices Mechanical and climatic test methods Part 35: Acoustic microscopy for plastic encapsulated electronic components
34、 3 General description Package cracking and electrical failure in plastic encapsulated SMDs can result when soldering heat raises the vapour pressure of moisture which has been absorbed into SMDs during storage. These problems are assessed. In this test method, SMDs are evaluated for heat resistance
35、 after being soaked in an environment which simulates moisture being absorbed while under storage in a warehouse or dry pack. 4 Test apparatus and materials 4.1 Humidity chamber The humidity chamber shall provide an environment complying with the temperature and relative humidity defined in 5.3. 4.2
36、 Reflow soldering apparatus The infrared convection, the convection and the vapour-phase reflow soldering apparatus shall provide temperature profiles complying with the conditions of soldering heat defined in 5.4.2 and 5.4.3. The settings of the reflow soldering apparatus shall be adjusted by tempe
37、rature profiling of the top surface of the specimen while it is undergoing the soldering heat process, measured as shown in Figure 1. BS EN 60749-20:200960749-20 IEC:2008 7 ThermocoupleHolderResinLead pinsDieAdhesive agent or thin tapeIEC 1746/01NOTE The adhesive agent or thin tape should have good
38、thermal conductivity. Figure 1 Method of measuring the temperature profile of a specimen 4.3 Holder Unless otherwise detailed in the relevant specification, any board material, such as epoxy fibreglass or polyimide, may be used for the holder. The specimen shall be placed on the holder by the usual
39、means and in a position as shown in Figure 1. If the position of the specimen, as shown in Figure 1, necessitates changing the shape of terminations and results in subsequent electrical measurement anomalies, a position that avoids changing the shape of terminations may be chosen, and this shall be
40、specified in the relevant specification. 4.4 Wave-soldering apparatus The wave-soldering apparatus shall comply with conditions given in 5.4.4. Molten solder shall usually be flowed. 4.5 Solvent for vapour-phase reflow soldering Perfluorocarbon (perfluoroisobutylene) shall be used. 4.6 Flux Unless o
41、therwise detailed in the relevant specification, the flux shall consist of 25 % by weight of colophony in 75 % by weight of isopropyl alcohol, both as specified in Annex B of IEC 60068-2-20:2008. 4.7 Solder Solder of composition as specified in Table 1 of IEC 60068-2-20:2008 shall be used. 5 Procedu
42、re 5.1 Initial measurements 5.1.1 Visual inspection Visual inspection, as specified in IEC 60749-3, shall be performed before the test. Special attention shall be paid to external cracks and swelling, which will be looked for under a magnification of 40. BS EN 60749-20:2009 8 60749-20 IEC:2008 5.1.2
43、 Electrical measurement Electrical testing shall be performed as required by the relevant specification. 5.1.3 Internal inspection by acoustic tomography Unless otherwise detailed in the relevant specification, internal cracks and delamination in the specimen shall be inspected by acoustic tomograph
44、y in accordance with IEC 60749-35. 5.2 Drying Unless otherwise detailed in the relevant specification, the specimen shall be baked at 125 C 5 C for at least 24 h. 5.3 Moisture soak 5.3.1 General Unless otherwise detailed in the relevant specification, moisture soak conditions shall be selected on th
45、e basis of the packing method of the specimen (see A.1.1). If baking the specimen before soldering is detailed in the relevant specification, the specimen shall be baked instead of being subject to moisture soak. 5.3.2 Conditions for non-dry-packed SMDs The moisture soak condition shall be selected
46、from Table 1, in accordance with the permissible limit of actual storage (see A.1.2.1). Table 1 Moisture soak conditions for non-dry-packed SMDs Condition Temperature C Relative humidity % Duration time h Permissible limit on actual storage A1 or B1 85 2 85 5 168 24 2 000 C 10 Method A 20 2,5 Method
47、 B 30 250 245 245 5.4.3 Method of heating by vapour-phase reflow soldering 5.4.3.1 Preparation The specimen shall be put on the holder. 5.4.3.2 Preheating Unless otherwise specified in the relevant specification, the specimen shall be preheated at a temperature from 100 C to 160 C for 1 min to 2 min
48、 in the vapour-phase soldering apparatus. 5.4.3.3 Solder heating The temperature of the specimen shall be raised after preheating. When the temperature of the specimen has reached 215 C 5 C, it shall be maintained for 40 s 4 s as shown in Table 6 (refer to A.3.2). Table 6 Heating condition for vapou
49、r-phase soldering Condition Temperature C Time s II-A 215 5 40 4 5.4.4 Method of heating by wave-soldering 5.4.4.1 Preparation The bottom surface of the specimen shall be fixed to the holder by an adhesive agent specified in the relevant specification. Unless otherwise detailed in the relevant specification, flux shall not be applied to the specimen and holder. NOTE 1 If flu
