1、 CENELEC EN*ba*flb8- 2-67 b m 3404583 0373569 8LT m BRITISH STANDARD Environmental testing Part 2. Tests Test Cy. Damp heat, steady state, accelerated test primarily intended for components The European Standard EN 600682-67 : 1996 has the status of a British Standard This part should be read in coq
2、jmction with BS EN 600681 : 1995 General and guidance ICs 19.040 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW BS EN 1996 1995 60068-2-67 : IEC 68-2-67 : BS EN 60068-2-67 : 1996 Committees responsible for this British Standard The preparation of this British Standard was ent
3、rusted to Technical Committee GEl50, Environmentai testing of electrotechnicai products, upon which the following bodies were represented: Federation of the Electronics Industry GAMBICA (BEAMA Ltd.) Society of Motor Manufacturers and Mers Limited Ministry of Defence The foliowing bodies were also re
4、presented in the drafting of the standard, through subcommittees and panels: Institute of Materials National SupeMsi Inspectorate (BSI PC) Society of Environmental Engineers Biodeterioration Society This British Standard, having been prepared under the direction of the Electrotechnical Sector Board,
5、 was published under the authority of the Standads Board and comes into effect on 15 June 1996 O BSI 1996 Amendments issued since publication Amd*No* ID b) it is capable of providing controlled conditions of temperature and relative humidity during testing, and the ramp-up to and ramp-down from spec
6、ifie test conditions; c) the temperature and humidity of the chamber can be monitored by means of sensing devices located in the working space and/or other areas giving the same results; d) any water shall be continuously drained from the working space and not re-used; e) condensed water is not allo
7、wed to fall on the specimen; f) the materials used in the construction shall not cause any significant corrosion of the specimen, or degradation of the quality of the humidifying water (see clause 6.1). The temperature tolerance of 12 OC is intended to take account of absolute errors in the measurem
8、ent, fluctuations of the chamber temperature at any point and variations between any two points within the working space. CENELEC EN*bO*Ob8- 2-b7 9b 3404583 O373576 T5T Temperature Relative humidity oc 1) % 2) 85 85 Page 4 EN 60068-2-67 : 1996 Duration 3, 4, h I II 111 IV 168 504 1 O00 2 O00 However
9、, in order to maintain the relative humidity within the specified tolerance of *5 %, it is necessary to keep the difference between any two points in the working space (at any instant) within narrower limits. The specified humidity tolerance will be exceeded if such temperature differences exceed 1,
10、5 “C. It is also necessary to restrict the short-term temperature fluctuations due to cycling of the chamber heater to a similar value. The specimen should not significantly impede the air flow. Condensation shall not be allowed to form on the specimen at any time during the test. 3.2 The humidifyin
11、g water Distilled or deionised water shall be used. The water shall have a resistivity of not less than 0,5 Macm at 23 “C. The pH value shall be between 6,O and 7,2 at 23 “C. Before the water is placed in the humidifier, all internal parts of the chamber shall be cleaned. Guidance on cleaning is giv
12、en in clause 6.3. The humidifier and/or test chamber shall be purged of all water after each test. 4 Severities The test severity, defined by the duration, shall be defined in the relevant specification. Unless otherwise specified, one of the durations given in table 1 shall be used. Table 1 - Sever
13、ities *) Tolerance for relative humidity: *5% 3, Tolerance for duration: 0% 45 4, Definition of duration: see 7.4.2 NOTE - It is not recommended that a test should be restarted; however if it is required to subject the specimen to a longer duration than 2 O00 h then the test shall be recommenced in
14、accordance with the requirements of clause 7. The test shall be recommenced within 96 h of the end of the ramp-down period of the previous test. During the interval between the tests the specimen shall be held under standard atmospheric conditions for measurement and tests, unless otherwise specifie
15、d in the relevant specification. Page 5 EN 60068-2-67 : 1996 5 Pre-conditioning The relevant specification may prescribe pre-conditioning 6 Initial measurements The specimen shall be submitted to the visual, dimensional and functional checks prescribed by the relevant specification. 7 Testing 7.1 an
16、d humidity, the specimen shall be installed in the working space in the chamber. With the chamber and specimen at the laboratory conditions of temperature, pressure 7.2 wall. The specimen shall not be subjected to radiant heat from the heaters or the chamber If required by the relevant specification
17、, a specific mounting structure shall be used. The heat conductivity and the thermal capacity of the mounting fixtures shall be sufficiently low so that for all practical purposes the specimen is thermally isolated. Care shall be exercised in the choice of mounting structure and mounting fixture mat
18、erials to minimise the effects of contamination and to minimise degradation due to corrosion and other mechanisms (see clause B.l). 7.3 during testing. Guidance on the application of bias is given in clause 8.2. If required by the relevant specification the specimen shall have a bias voltage applied
19、 The bias voltage (or bias voltage cycle) shall be applied to the specimen when the temperature and the relative humidity have reached the stable state and continue until the specimen is under recovery conditions. 7.4 Test cycle 7.4.1 The temperature and relative humidity of the chamber shall be rai
20、sed to their appropriate values. During this period the temperature and the relative humidity shall not exceed the specified value. Condensed water is not allowed on the specimen at any time during the test cycle. Stabilisation of temperature and humidity shall take place within 3 h. 7.4.2 The tempe
21、rature and relative humidity shall be maintained within the prescribed limits for a duration as specified in the relevant specification. The duration shall commence as soon as the conditions have stabilised. 7.4.3 At the end of the specified duration, the chamber temperature and relative humidity sh
22、all be restored to standard atmospheric conditions for measurement and tests in not less than 1 h and not more than 4 h. During this period, the temperature and the relative humidity shall not exceed the specified value. The bias shall be maintained during this period. CENELEC EN*bD*ObB- 2-b7 96 340
23、4583 0173578 822 = Page 6 EN 60068-2-67 : 1996 7.4.4 procedure. On completion of the cooling period the specimen shall be subjected to the recovery 8 Intermediate measurements The relevant specification may require electrical and/or mechanical checks during testing. If it is required to make interme
24、diate measurements, the relevant specification shall define the measurements and period) during testing after which they shall be carried out. The measurements shall not cause any change to the test conditions. Measurements preceded by recovery which would require removal of the specimen from the ch
25、amber are not permissible during testing. 9 Recovery Upon completion of testing the specimen shall be allowed to recover. Unless otherwise specified in the relevant specification, recovery shall be not less than 2 h and not more than 24 h at standard atmospheric conditions for measurement and tests.
26、 10 Final measurements The specimen shall be submitted to the visual, dimensional, and functional checks prescribed by the relevant specification. 11 Information to be given in the relevant specification When this test is included in a relevant specification, the following details shall be given, in
27、 so far as they are applicable. The relevant specification shall supply information as required in the clauses listed below, paying particular attention to the items marked with an asterisk (*), as this information is always required. Clauselsubclause a) Test severity (duration) . c) Pre-conditionin
28、g * . e) Specific mounting structures . b) Atmospheric conditions between tests (if not standard) . d) Initial measurements f) Bias voltage g) Intermediate measurements h) Recovery i) Final measurements * . 4 4 5 6 7.2 7.3 and 8.2 8 9 10 CENELEC EM%60*068- 2-67 9b 3404583 0373579 7b9 = Page 7 EN 600
29、68-2-67 : 1996 Annex A (informative) Physical significance of the test A.l The acceleration of the penetration of water-vapour into the specimen is the most important physical factor in the accelerated damp heat test. The acceleration is due to the difference in partial pressure of water-vapour betw
30、een the inside of a non-hermetically sealed specimen and the test environment. A.2 In the first instance this test was applied to accelerate the corrosion of aluminium metallisation in both integrated circuits and other semiconductor devices in plastic encapsulation. However, when considering the ap
31、plication of the test to other products it is important that the failure mode or modes are determined, and the appropriate degradation process and test severity selected in response to each failure mode. CENELEC EN*bO*Ob8- 12-67 9b = 3404583 0373580 480 Page 8 EN 60068-2-67 : 1996 Annex B (informati
32、ve) Test apparatus and handling B.l Selection of materials Care exercised in the choice of materials to be used in the chamber will minimise the release of contamination and the degradation due to corrosion and other mechanisms under the combined conditions of humidity and temperature defined in the
33、 test. Suitable materials are: stainless steel, glass, ceramic, and others which resist corrosion. 8.2 Bias voltage Bias voltage is defined as that voltage which is applied for test purposes in order to enhance the effects of humidity. It is not necessarily concerned with the normal functioning of t
34、he specimen. The bias should be applied in accordance with the following guidelines, which are given in order of decreasing importance: a) The temperature increase of defined locations within and at the surface of the specimen should be less than 2 “C with respect to the nominal temperature of the w
35、orking space. b) Care should be exercised when choosing the voltage to both promote hydrolysis and to limit self-heating of the specimen, since this will affect the penetration and/or absorption of moisture. Where it is not possible to prevent significant self-heating with continuous bias applied, i
36、t is recommended that the bias should be applied intermittently. Unless otherwise specified, the periods should be 3 h off followed by 1 h on. The sequence should commence with the bias off. c) Precautions should be taken to limit energy dissipation due to faulty conditions. NOTE - Applying bias to
37、the specimen at a constant relative humidity enhances the moisture induced effects. On the other hand. bias induces power dissipation which may lead to an effect which is contrary to the intention of the test since it reduces the relative humidity of the critical locations by increasing the local te
38、mperature. 8.3 Cleaning Cleaning of the chamber and all internal fixtures (racks, etc.) placed in the chamber is essential. The test chamber and internal fixtures may be cleaned with diluted laboratory detergent using a soft brush, and rinsed with distilled or deionised water. It is recommended that
39、 the chamber be cleaned prior to each test. It is recommended that gloves and face masks be used as a precaution against the contamination of the test chamber and of the internal fixtures when cleaning and that the equipment be operated in a suitably clean area. Unless otherwise specified, the speci
40、men should be tested in the “as received” condition and following normal handling. Tests on a specimen which has been specially cleaned prior to the test may not give an indication of effects which occur in service. CENELEC EN*bO*ObA- 2-67 9b 3904583 0373583 337 M BS EN 1996 1995 60068-2-67 : IEC 68
41、-2-67 : BSI 389 Chiswick High Road London w4 4AL BSI - British Standards Institution BSI is the independent nationai body responsible for preparing British Standards. It presents the UK view on standars in Europe and at the intemationai level. It is incorporated by Royal Charter. Contract requiremen
42、ts A British Standard does not purport to include ail the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Revisions British Standards are updated by amendment or revision. Users of British Standards should make sure that they possess the
43、latest amendments or editions. It is the constant aim of BSI to improve the quaiity of our products and services. We would be grateful if anyone finding an inaccuracy or ambiguity while using this British Standard would inform the Secretary of the responsible technical committee, the identity of whi
44、ch can be found on the inside front cover. Tel 0181 996 9ooO; Fax: 0181 996 7400. BSI offers members an individual updahng service cailed PLUS which ensures that subscribers automatically receive the latest editions of standards. Buying standards Orders for ali BSI, intemationai and foreign standard
45、s publications should be addressed to Customer Services, Sales Depariment at Chiswick Tel 0181 996 7000; Fax: 0181 996 7001. In response to orders for intemationai standards, it is BSI policy to supply the BSI implementation of those tha have been published as British Standards, unless otherwise req
46、uested. Information on standards BSI provides a wide range of information on nationai, European and intemationai standards through its Library, the Standardiine Database, the BSI Infomiation Technology Service (BlTS) and its Technical Help to Exporters Service. Contact the Information Department at
47、Chiswick Tel 0181 996 7111; Fax: 0181 996 7048. Subscribing members of BSI are kept up to date with standards developments and receive substantial discounts on the purchase price of standards. For details of these and other benefits contact Customer Services, Membership at Chiswick Tel 0181 996 7002
48、; Fax: O181 996 7001. Copyright Copynght subsists in ail BSI publications. BSI also holds the copyright, in the UK, of the publications of the intemationai standardization bodies. Except as permitted under the Copyright, Designs and Patents Act 1988 no extract may be reproduced, stored in a retrieva
49、l system or transmitted in any form or by any means - electronic, photocopying, recording or otherwise - without prior written permission from BSI. This does not preclude the free use, in the come of implementing the standard, of necessary details such as symbols, and size, type or grade designations. If these details are to be used for any other purpose than implementation then the prior written permission of BSI must be obtained. If permission is granted, the terms may include royaity payments or a licensing agreement. Details and advice can be obtained from the Copyright Ma
