JEDEC JEP131B-2012 Potential Failure Mode and Effects Analysis (FMEA).pdf

1、JEDEC PUBLICATION Potential Failure Mode and Effects Analysis (FMEA) JEP131B (Revision of JEP131A, May 2005) APRIL 2012 JEDEC SOLID STATE TECHNOLOGY ASSOCIATION NOTICE JEDEC standards and publications contain material that has been prepared, reviewed, and approved through the JEDEC Board of Director

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9、 3103 North 10th Street Suite 240 South Arlington, VA 22201-2107 or refer to www.jedec.org under Standards-Documents/Copyright Information. JEDEC Publication No. 131B -i- POTENTIAL FAILURE MODE AND EFFECTS ANALYSIS (FMEA) Contents PageIntroduction II1 Scope 12 Terms and definitions 13 FMEA Requireme

10、nts 33.1 Creation process 33.2 FMEA Identification 43.3 Process/product function/requirements 43.3.1 PFMEA 3.3.2 DFMEA 3.4 List of potential failure modes 53.5 Description of the potential effects of each failure 53.6 Comparison and review 63.7 Quantification of the potential effect(s) of failure: S

11、everity (S) 63.8 Potential cause(s)/mechanism(s) of failure 63.9 Quantification of the Occurrence (O) of the failure 73.10 Current process controls 73.11 Quantification of the Detection (D) probability of the failure 73.12 Detection (D) probability of the failure in DFMEAs 83.13 Quantification of th

12、e overall risk by the Risk Priority Number (RPN) 83.14 Recommended action(s) 83.15 Responsibility (for recommended action) and target completion date 93.16 Actions taken 93.17 Resulting RPN 93.18 Classification 94 Follow-up 9Annexes A: Template 10B: Example PFMEA 11C: Example DFMEA 12D: Severity Met

13、ric 13E: Occurrence Rankings 14F: Detectability Rankings 15G: Changes of Document 16JEDEC Publication No. 131B -ii- Introduction An FMEA is an anticipatory thought process designed to utilize as much knowledge and experience of an organization as possible toward the end of addressing potential issue

14、s defined in a new project. The objective is to reduce the probability that a customer is exposed to a potential product and or process problem by performing a thorough risk analysis. A collection of subject matter experts from a number of various disciplines should be brought together to think abou

15、t potential problems that could occur in a product and or process sometime in the future. Individuals do not necessarily have to be directly involved with the product and or the process; experience in a particular discipline may be of greater value than direct knowledge of the product and or the pro

16、cess. Ideally, representatives of the entire supply chain including customers and suppliers should also be contributors in the process. Because of the need to continually improve whenever possible, there is a need for using FMEA as a disciplined technique to identify and help eliminate potential con

17、cerns. It is meant to be a “before-the-event“ action, not an “after-the-fact“ exercise. To achieve the greatest value, the FMEA should be performed before a failure mode has been unknowingly planned into a product (DFMEA) and or process (PFMEA). Up front time spent in performing a comprehensive FMEA

18、, when product and or process changes can be most easily and inexpensively implemented, will alleviate late change crises. The outcome of the FMEA procedure should be a list of defined actions that will either prevent the occurrence of a problem through a design or process change, or improve the cha

19、nces of detection of a problem through monitoring, if it does occur in the future. Actions are prioritized and decisions made as to which actions will have resources assigned for implementation. It is not appropriate to compare one groups FMEA numerical rating with another groups FMEA, as each group

20、s knowledge and experience are unique. Since an FMEA procedure anticipates the future the numerical rating is a subjective value not an objective value. A regular FMEA review can be conducted any time before a change is being made to a product design and or to a process or new knowledge about risks

21、is generated by learning from field failures. An FMEA can also reduce or eliminate the chance of implementing a corrective change that could create an even larger concern. Properly applied, it is an interactive process that is never ending. JEDEC Publication No. 131B Page 1 POTENTIAL FAILURE MODE AN

22、D EFFECTS ANALYSIS (FMEA) (From JEDEC Board Ballot JCB-11-86, formulated under the cognizance of JC-14 Committee on Quality and Reliability of Solid State Products.) 1 Scope This publication applies to electronic components and subassemblies product and or process development, manufacturing processe

23、s and the associated performance requirements in customer applications. These areas should include, but are not limited to: package design, chip design, process development, assembly, fabrication, manufacturing, materials, quality, service, and suppliers, as well as the process requirements needed f

24、or the next assembly. The publication covers the types of FMEAs described in Table 1. The purpose of this document is to establish a minimum guideline for the application of Failure Mode and Effects Analysis techniques to improve quality, reliability, and/or consistency of electronic components suba

25、ssemblies by continually evaluating the product and or process against potential failure modes. OEMs must provide suppliers with their manufacturing processes, their use conditions on the failed parts, and their failure experience(s). Suppliers must seek continuous improvement and have the responsib

26、ility of developing and improving the elements of FMEA. Table 1 Types of FMEAs DFMEA PFMEA Element to be assessed Elements of a product (function / module) or process of record (POR) Process steps of a production process or design flow Potential failure modes Deviations caused by the design of a pro

27、cess or product Deviations in the process Potential effects of the failures Deviations from product specifications Deviations from the process requirements 2 Terms and definitions The following are the terms included in the body of the text. Definitions marked by an asterisk (*) are taken from EIA 5

28、57, General Standard for Statistical Process Control (SPC). They are replicated here for completeness. characteristic*: A distinguishing feature of a process or its output on which variables or attributes data can be collected. control*: A corrective action process based on feedback. design FMEA (DF

29、MEA): A systematic method to assess the risks of the elements of a product or POR and their interactions in terms of functionality as defined by product or POR specification. JEDEC Publication No. 131B Page 2 2 Terms and definitions (contd) design of experiments (DOE): An efficient method of experim

30、entation that identifies factors that affect the mean and variation with minimum testing. failure: (1) The loss of the ability of a component to meet the electrical or physical performance specifications that (by design or testing) it was intended to meet. (2) A component that has failed. failure mo

31、de and effect analysis (FMEA): A systematized group of activities intended to recognize, evaluate, and prioritize the potential failure modes of a product or process and the effects of a failure, and then to identify actions that could reduce the probability of occurrence of each failure mode, liste

32、d in the order of seriousness of a potential failure in the customers application. NOTE 1 The FMEA provides a structured analysis in order to assess the probability of occurrence of a failure from the failure mode as well as the effect of the failure. NOTE 2 A fully developed FMEA is continuously ma

33、intained and updated to reflect the latest actions and changes to the design or process. node*: A definable point in the process at which form, fit, or function is altered. Pareto analysis: A technique for problem-solving in which all potential problem areas or sources of variation are ranked accord

34、ing to their contribution. potential cause of failure: A property, characteristic, or occurrence that could lead to a failure, described in terms of something that can be corrected or controlled. potential failure mode: The manner in which the process could potentially fail to meet the process requi

35、rements and/or design intent. NOTE Potential failure mode is a description of the nonconformance at that specific operation. It can be a cause associated with a potential failure mode in a subsequent (downstream) operation or an effect associated with a potential failure in a previous (upstream) ope

36、ration. However, when the failure mode and effect analysis (FMEA) is prepared, the assumption should be made that the incoming part(s)/material(s) are correct. process*: (1) A combination of people, procedures, methods, machines, materials, measurement equipment, and/or environment for specific work

37、 activities to produce a given product or service. (2) A repeatable sequence of activities with measurable inputs and outputs. process change: A change in processing that could alter the capability of the process to meet the design requirements or durability of the product. process of record (POR):

38、A detailed description of the production process flow. process FMEA (PFMEA): A systematic method to assess the risks of the elements of a process and their interactions of a production or business process in terms of process requirements. risk priority number (RPN): A parameter to measure the rating

39、 of risks. JEDEC Publication No. 131B Page 3 3 FMEA requirements Experts from all disciplines are needed to properly assess the product(s) and or process(es) under consideration. A collection of subject matter experts from a number of various disciplines should be brought together to think about pot

40、ential problems that could occur in a product and or process sometime in the future. Individuals do not necessarily have to be directly involved with the product and or the process; experience in a particular discipline may be of greater value than direct knowledge of the product and or the process.

41、 Ideally, representatives of the entire supply chain including customers and suppliers should also be contributors in the process. 3.1 Creation process A Design FMEA (DFMEA) should begin with a block diagram of the product this allows the participants to envision how various components or sub-assemb

42、lies will interact. The effects identified on an appropriate process FMEA can be used as input to a design FMEA to help identify objective values for occurrence and detection based on historical data. A Process FMEA (PFMEA) should begin with a flow diagram that shows the association of each operatio

43、n (see Annex B for an example). When a process and or a product is being modified or a sub process added, it is not necessary to start the FMEA from the beginning, it is more appropriate to start by using an existing FMEA and concentrate on the new topics. The block diagram or flow chart is then use

44、d to assist the group to anticipate potential problems in a structured way; this can be conducted through various brainstorming techniques. If applicable, FMEAs of design or process blocks could be reused from other FMEAs. All areas must be considered including design, materials, manufacturing, deli

45、very etc. For each potential problem the group must then identify what the effect will be and to attach a subjective value to each item that is based on how severe they think the potential effects are. Continuing the thought process, a potential cause of each of the problems must be defined and a de

46、termination of how often they may occur. Using their experience the group must determine how good they believe existing procedural or process controls will be for both preventing the problem but also detecting the problem if it does occur. Using the numerical values that were determined for the seve

47、rity, the possible number of occurrences and the ability to detect the failure mode, a prioritization of the risk of each failure mode probability can be made by calculating the Risk Priority Number (RPN). For details see 3.7, 3.9, 3.11 and 3.12. Starting with the potential failure modes with the hi

48、ghest severity number the group then determines what actions can be taken to improve prevention or detection. When action for the high severity items have been identified the group should continue to identify actions to prevent or detect those items with the highest RPN The action list then allows r

49、esources to be allocated and objectives to be set that will help to reduce the potential risk to the customer in the future. When the actions have been implemented and the results have been evaluated the RPNs should be recalculated, determination of actions for those items with the highest severity numbers and RPNs may have to be repeated until the RPN is at an acceptable level. JEDEC Publication No. 131B Page 4 3.1 Creation process (contd) In order to facilitate documentation of the analysis of potential failures and their effect, an example PFMEA form was developed and is included as