1、BRITISH STANDARD BS IEC 61163-2:1998 Reliability stress screening Part 2: Electronic components ICS 31.020BSIEC 61163-2:1998 This British Standard, having been prepared under the directionof the Management Systems Sector Committee, waspublished under the authorityof the Standards Committee and comes
2、 into effect on 15 February 1999 BSI 05-1999 ISBN 0 580 30923 1 National foreword This British Standard reproduces verbatim IEC61163-2:1998 and implements it as the UK national standard. The UK participation in its preparation was entrusted by Technical Committee DS/1, Dependability and terotechnolo
3、gy, to Subcommittee DS/1/1, Dependability, which has the responsibility to: aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related internationa
4、l and European developments and promulgate them in the UK. A list of organizations represented on this subcommittee can be obtained on request to its secretary. From 1 January 1997, all IEC publications have the number 60000 added to the old number. For instance, IEC 27-1 has been renumbered as IEC6
5、0027-1. For a period of time during the change over from one numbering system to the other, publications may contain identifiers from both systems. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Stand
6、ards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible f
7、or their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, theCEI IEC title page, page ii, pages 1 to 24 and a back cover. This standard has
8、 been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Amendments issued since publication Amd. No. Date CommentsBSIEC 61163-2:1998 BSI 05-1999 i Contents Page National foreword Inside front cover Text of
9、CEI IEC 61163-2 1ii blankBSIEC61163-2:1998 ii BSI 05-1999 Contents Page Introduction 1 1 Scope 1 2 Normative references 1 3 Definitions 2 4 Procedure 2 4.1 General 2 4.2 Programme definition 4 4.3 Establish contact between the two parties involved 4 4.4 Identify the possible flaws and failure modes
10、for each component 4 4.5 Select stress types, stress levels and stress sequence to be used in order toprecipitate failures 5 4.6 Determine the duration of the reliability stress screening process 5 4.7 Mathematically analyze initial test results 5 4.8 Perform failure analysis 5 4.9 Perform stress se
11、quence on the components 6 4.10 Determine approval or rejection criteria 6 4.11 Develop closed-loop corrective action process 6 4.12 Provide feedback to the component manufacturers 6 4.13 Discontinue the reliability stress screening process 6 Annex A (informative) Examples of tools for identifying f
12、ailure mechanismsinelectronic components 8 Annex B (informative) Data analysis 10 Annex C (informative) Examples of applications of reliability stress screeningprocesses. 18 Figure 1 Component reliability screening process (general flow chart) 3 Figure 2 Corrective action process 7 Figure B.1 Nomogr
13、aph of the cumulative binomial distribution (Larson) 11 Figure B.2 Estimation of and 13 Figure B.3 Example of a weibull plot 14 Figure C.1 Weibull plot of the bump test 22 Figure C.2 Weibull plot of the pull test 24 Table A.1 Tools for identifying potential flaws 8 Table B.1 Screening test results 1
14、4 Table B.2 Screening test results for weak populations 15BSIEC61163-2:1998 BSI 05-1999 1 Introduction Although first developed as a tool for designing reliability into systems that operate in harsh environmental conditions, reliability stress screening has emerged as a technique in the electrotechn
15、ical manufacturing community that is useful if the drive toward zero defect levels in new products is to continue. Reliability stress screening has proved to be an effective tool in a) identifying and removing flaws due to poor component design and manufacturing deficiencies, b) screening parts to a
16、 tighter specification than those published, c) providing feedback to enable the streamlining of processes to achieve very tight limits in order to minimize parameter variability. Reliability stress screening should not be considered as a normal procedure to be used in assuring the reliability of el
17、ectronic components because reliability stress screening cannot improve the reliability of an individual component. Reliability stress screening can, however, improve the actual reliability of a system. The cost and risks generally outweigh the potential benefits since any applied stress may have de
18、trimental effects on the lifetime of the components. Greater benefits may be obtainable by tighter manufacturing process control. However, in some cases, this may not be practical, for example with existing components with less than acceptable reliability. Using reliability stress screening to upgra
19、de component specifications can also lead to a logistical problem, when similarly screened components are not available at a later date. When performing reliability stress screening on components for use in a particular system, either enough components needed for the repair of the system over its en
20、tire service life need to be screened initially or the user needs to ensure that system documentation be sufficient to control component procurement so that all replacement components be similarly screened. 1 Scope This part of IEC61163 provides guidance on reliability stress screening techniques an
21、d procedures for electronic components. This standard is not, and cannot be, exhaustive due to the rapid rate of developments in the electronics industry. This standard is intended for the use of a) component manufacturers as a guideline, b) component users as a guideline to negotiate with component
22、 manufacturers on stress screening requirements or plan a stress screening process in house due to reliability requirements, c) subcontractors who provide stress screening as a service. This standard is not intended to provide test plans for specific electronic components or for delivery of certific
23、ates of conformance for batches of components. 2 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this part of IEC61163. At the time of publication, the editions indicated were valid. All normative documents are
24、 subject to revision, and parties to agreements based on this part of IEC61163 are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. IEC 6005
25、0(191):1990, International Electrotechnical Vocabulary (IEV) Chapter191:Dependability and quality of service. IEC 60300-1:1993, Dependability management Part 1: Dependability programme management. IEC 60300-2:1995, Dependability management Part2: Dependability programme elements and tasks. IEC 60300
26、-3-7: , Dependability management Part3-7: Application guide Reliability stress screening of electronic hardware 1) . IEC 61163-1:1995, Reliability stress screening Part 1: Repairable items manufactured in lots. IEC 61709:1996, Electronic components Reliability Reference conditions for failure rates
27、and stress models for conversion. 1) To be published.BSIEC61163-2:1998 2 BSI 05-1999 3 Definitions For the purpose of this part of IEC61163, the following definitions as well as those given in IEC60050(191) and IEC60300-3-7 apply: 3.1 reliability screening (process) a process of detection of flaws a
28、nd removal and repair of weak items for the purpose of reaching as rapidly as possible the reliability level expected during the useful life NOTE 1IEC 60050(191) defines in 191-17-02, the term “burn-in”. This term, however, is used by many manufacturers to describe a so-called “soak-test”, which is
29、only one of many possible ways of screening. Furthermore “burn-in” may include ageing, the purpose of which is to stabilize parameters, and where in many cases no failures occur. NOTE 2IEC60050(191) defines, in 191-14-09, the term “screening test”. This term, however, is defined too broadly to be ap
30、plicable in the present context because it encompasses screening of any types of non-conformities. Furthermore, reliability screening is a process, not a test. NOTE 3Repair is not applicable in the case of electronic components. 3.2 reliability stress screening (process) a process using environmenta
31、l and/or operational stress as a means of detecting flaws by precipitating them as detectable failures NOTEReliability screening is designed with the intention of precipitating flaws into detectable failures. An ageing process designed specifically with the intention of stabilizing parameters is not
32、 a reliability stress screening process and is therefore outside the scope of this standard. 3.3 weak item an item which has a high probability of failure in the early failure period due to a flaw (see also3.8: early failure period) 3.4 weakness any imperfection (known or unknown) in an item, capabl
33、e of causing one or more weakness failures NOTE 1Each type of weakness is assumed to be statistically independent of all other such types. NOTE 2A weakness may be either inherent or induced. 3.5 weakness failure a failure due to a weakness in the item itself when subjected to stresses within the sta
34、ted capabilities of the item IEV191-04-06 3.6 flaw a weakness in an item which gives rise to early weakness failures 3.7 inherent flaw a flaw in an item related to its technology and manufacturing process 3.8 early failure period that early period, if any, in the lifetime of an item, beginning at a
35、given instant of time and during which the instantaneous failure intensity for a repaired item or the instantaneous failure rate for a non-repaired item is considerably higher than that of the subsequent period IEV191-10-07 NOTEThe early failure period is the period where the weak items fail. 4 Proc
36、edure 4.1 General In designing a stress programme, it is important to understand the purpose of the programme as to whether it is: a) to improve the process capability by understanding and eliminating causes of failures; b) to achieve tighter performance on screened devices compared to published spe
37、cifications; c) to understand and improve reliability of new device technologies; d) to remove weak devices which may fail early. It is important to note that there are two types of failures: time-dependent failures; the mechanisms that cause these failures are stress-dependent and will cause degrad
38、ation of the device given sufficient time. The techniques used to accelerate these failure mechanisms should not affect good devices; time-independent failures; these failure mechanisms are due to latent flaws that do not affect devices in normal operation unless induced by some external events. Car
39、e should be taken when choosing the techniques used to accelerate these failures since damage to good components is possible if the screen is too harsh. In all the above cases, the screening will start at100%, gradually reduce and finally be eliminated after analysis of failures is made and follow-u
40、p actions are taken.BSIEC61163-2:1998 BSI 05-1999 3 It is important that the aim for a reliability stress screening be carefully considered. No reliability stress screening procedure should be used routinely. There is to be a clear reason why reliability stress screening is chosen (for example econo
41、mic reasons). In order to get the best possible results from a stress screen, it is necessary to fully understand the failure mechanisms of the components to be screened and how the application of any particular screen will affect these mechanisms. Care should be taken so that only the failure mecha
42、nisms likely to occur while the component is operating in the field are accelerated by the screen, since it is relatively easy to induce unlikely failure mechanisms by misapplication of screening stress. Before and after any screen is applied, functional testing of each part to be screened should be
43、 performed. Firstly, this testing is done so that only those parts that fail as a result of the stress screen should be recorded as failing for that reason. Secondly, the stress screen is applied to every component for the specified period of time and under the specified conditions. Thirdly, every c
44、omponent is tested functionally again, in order to remove any failed parts from the good product population. Functional testing may not be sufficient for components which are particularly delicate or costly, such as lasers. In these cases, a parametric test may be necessary. Figure 1 Component relia
45、bility screening process (general flow chart)BSIEC61163-2:1998 4 BSI 05-1999 The reliability stress screening performed in this manner can be used to determine the yield of the screen for the lot of components screened. This screen yield data may be compared to data for yield without screen applicat
46、ion and both these types of data may be compared in turn to system yield data, and ultimately to system field return data, all in order that the effectiveness of the screen may be monitored. In order to use reliability stress screening of electronic components effectively, the type of failure(s) exp
47、ected should be understood. Then the details of the stress screen programme, including stress levels and screen durations, should be planned. The reliability stress screening methodology cannot be described in detail since there are many different component types. Therefore, it is not advisable to c
48、omprehensively list reliability screening procedures for particular component types. A general procedure, however, can be recommended for designing a specific reliability stress screening plan (see4.2). It is important to note that all the steps of such a procedure need not be used in designing ever
49、y reliability stress screening plan. 4.2 Programme definition The following procedure for setting up and running a reliability stress screening process is recommended: establish contact between the two parties involved identify the possible flaws and failure modes for each component select stress types, stress levels and stress sequence to be used in order to precipitate failures determine the duration of the reliability stress screening process mathematically analyze initial test results perform failure analysis
