SAE GEIA-HB-0005-2-2007 Technical Guidelines for Aerospace and High Performance Electronic Systems Containing Lead-free Solder and Finishes.pdf

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4、side USA)Fax: 724-776-0790Email: CustomerServicesae.orgSAE WEB ADDRESS: http:/www.sae.orgSAE values your input. To provide feedbackon this Technical Report, please visithttp:/www.sae.org/technical/standards/GEIAHB0005_2TECHNICAL REPORT GEIA-HB-0005-02Issued 2007-11Reaffirmed 2016-06Technical Guideli

5、nes for Aerospace and High PerformanceElectronic Systems Containing Lead-free Solder and FinishesNOTICEThis document has been taken directly from the original TechAmerica document and contains only minor editorial and format changes required to bring it into conformance with the publishing requireme

6、nts of SAE Technical Standards. The release of this document is intended to replace the original with the SAE International document. Any numbers established by the original document remain unchanged.The original document was adopted as an SAE publication under the provisions of the SAE Technical St

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8、 specification or standard format.TechAmericaEngineeringBulletinTechnical Guidelines for Aerospace and High Performance Electronic Systems Containing Lead-free Solder and inishesFGEIA-HB-0005-2November 2007 GEIA-HB-0005-2NOTICETechAmerica Engineering Standards and Publications are designed to serve

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12、 nor does it assume any obligation whatever to parties adopting the Standard or Publication. Technical Publications are distinguished from TechAmerica Standards in that they contain a compilation of engineering data or information useful to the technical community and represent approaches to good en

13、gineering practices that are suggested by the formulating committee. This Bulletin is not intended to preclude or discourage other approaches that similarly represent good engineering practice, or that may be acceptable to, or have been accepted by, appropriate bodies. Parties who wish to bring othe

14、r approaches to the attention of the formulating committee to be considered for inclusion in future revisions of this publication are encouraged to do so. It is the intention of the formulating committee to revise and update this publication from time to time as may be occasioned by changes in techn

15、ology, industry practice, or government regulations, or for other appropriate reasons. (Formulated under the cognizance of the TechAmerica (APMC) Avionics Process Management Committee and the (G-12) Solid State Devices Committee. This is a joint activity of the Aerospace Industries Association (AIA)

16、, Avionics Maintenance Conference (AMC), and TechAmerica, to address aerospace issues related to the global elimination of lead from electrical and electronic equipment put on the market after July 1, 2006. Formed in 2004, this coalition includes all stakeholders (market segments, supply chain, geog

17、raphic regions.)Published by 2010 TechAmericaStandards and was balloted and approved by GEIA G-12 (Solid State Subcommittee) and the GEIA Avionics Process Management Committee. This handbook is intended to work in concert with the Lead-free performance standard (GEIA-STD-0005-1), the program managem

18、ent/systems engineering guidelines (GEIA-HB-0005-1), and the tin whisker mitigation standard (GEIA-STD-0005-2). Part way through this documents creation, it was evident that three additional documents were needed. As a result, the performance test standard (GEIA-STD-0005-3), the rework and repair ha

19、ndbook (GEIA-HB-0005-3) and the reliability assessment handbook (GEIA-HB-0005-4) have been added to address testing, rework, and reliability prediction respectively.This handbook may be referenced in proposals, requests for proposals, work statements, contracts, and other aerospace and high performa

20、nce industry documents. IntroductionThe global transition to Pb-Free electronics impacts the aerospace and other industries having high reliability applications in various ways. In addition to the perceived need to replace the Tin-Lead solders used as an interconnect medium in electronic and electri

21、cal systems, the following variations to established practice will need to be considered:x Components and printed circuit boards will need to be able to withstand higher manufacturing process temperatures. x Printed circuit boards will need to have robust solderable Pb-Free surface finishes. x Manuf

22、acturing and inspection techniques are needed that yield repeatable reliability characteristics.x At least initially, Pb-free alloys used within the equipment should be restricted to those that are compatible with Tin-Lead soldering systems. x A maintenance strategy should be developed that will fac

23、ilitate the support repair of new and existing equipment throughout a 20+ year life. This document will establish guidelines for the use of Pb-Free solder and mixed Tin-Lead/Lead-free alloy systems while maintaining the high reliability standards required for aerospace GEIA-HB-0005-2ivelectronic and

24、 electrical systems. Currently the largest volume of Lead (Pb) in many of these electronic systems is in the Tin-Lead eutectic (Sn-37Pb) and near eutectic alloys (Sn-36Pb-2Ag, Sn-40Pb) used in printed circuit board assemblies, wiring harnesses and electrical systems. High-Lead solder alloys are not

25、specifically addressed in this document; however, many of the methodologies outlined herein are applicable for their evaluation.A good deal of the information desired for inclusion in this technical guidelines document does not exist. A large number of Pb-Free investigative studies for aerospace and

26、 high reliability electronic and electrical systems are either in progress or in the initiation stage. The long durations associated with reliability testing necessitates a phased release of information. The information contained herein reflects the best information available at the time of document

27、 issuance. It is not the goal of this document to provide technical guidance without an understanding of why that guidance has technical validity or without concurrence of the technical community in cases where sufficient data is lacking or conflicting. The document will be updated as new data becom

28、es available. Further complicating matters are the facts that no single alloy across the supply base will be replacing the heritage Tin-Lead eutectic alloy and that it is not likely that qualification of one alloy covers qualification for all other alloys. Given the usual requirement for long, high

29、performance electronic service lives, any Pb-Free alloy must have predictable performance when mixed with heritage Tin-Lead alloys. Pb-Free alloys containing elements such as Bismuth (Bi) or Indium (In) that can form alloys having melting points within the equipments operating temperature range must

30、 be considered very carefully before use. Although Pb-Free solder alloys are still undergoing some adjustments, it appears that the Sn-Ag-Cu family of alloys will be used for surface mount assembly and either Sn-Ag-Cu, Sn-Cu or Sn-Cu-Ni (Sn-Cu stabilized with Nickel) alloys will be dominant in wave

31、solder applications. In addition, some applications are using the Sn-Ag alloy family 1 2 3.The majority of the Pb-Free solder alloys being considered have higher melting temperatures than Tin-Lead eutectic solder. In order to make use of the Pb-Free solders, changes to the molding compound, die atta

32、ch and printed circuit board insulation systems are being introduced to accommodate the 30 to 40 C higher (54 to 72 F higher) processing temperature. Thus, not only is the Pb-Free transition changing the solder alloy, but a significant portion of the electronic packaging materials are changing as we

33、ll. The higher melting point, greater creep resistance and higher strength of the Pb-Free alloys have driven a significant amount of study into the thermal cycling and mechanical vibration/shock assessments of these new alloys. The consumer electronics industry has invested considerable resources to

34、 ensure that Pb-Free solder will perform adequately for their products. Creep resistance of Pb-free alloys can vary considerably from heritage Tin-Lead solders. The creep/stress relaxation performance of the solder depends on the stress level, temperature and time for a specific solder material and

35、joint composition. Therefore, one needs to establish what the acceleration factor is between a particular test condition and application. The interpretation of the results of a head-to-head testing needs to be assessed in terms of the anticipated service conditions with respect to these acceleration

36、 factors. Thermal preconditioning prior to thermal cycling should be considered in GEIA-HB-0005-2vthe Pb-free solder assessment plan particularly as it relates to changes in solder microstructure. Modeling/Analysis is needed to properly compare the Tin-Lead and Pb-Free alloy performance and correct

37、for the stress relaxation differences obtained for the various piece-parts and thermal cycling conditions.While there is much data on near eutectic SAC (e.g., 305 and 405) Pb-Free thermal cycling, there is less information regarding Pb-Free vibration and shock performance. Fortunately, the vibration

38、 and shock performance data can be obtained relatively quickly. During vibration/shock testing, the near eutectic SAC Pb-Free solder behaves more rigidly than the Sn-Pb solder transferring greater loads to the interfaces between the solder alloy and the substrate interfaces. The increased amount of

39、Tin in Pb-Free alloys increases the intermetallic thickness when Copper substrates are used. In addition, when Nickel or electroless Nickel (Nickel Phosphorous) substrates are used, the increased Copper in the SAC alloy can result in the formation of intermetallics on the nickel interface, which are

40、 less robust than Sn-Cu or Sn-Ni intermetallics that are typical of Tin-Lead solder joints. Mechanical test results to-date suggest that a robust assessment of Pb-Free alloy assembly in vibration and shock environments will need to include thermal aging for interface and microstructural stabilizatio

41、n prior to any dynamic mechanical testing. Alloys other than SAC should be assessed to determine their vibration and shock performance characteristics. GEIA-HB-0005-211. Scope This document is intended for use as technical guidance by Aerospace system suppliers, e.g., Aerospace system Original Equip

42、ment Manufacturers (OEMs) and Aerospace system maintenance facilities, in developing and implementing designs and processes to assure the continued performance, quality, reliability, safety, airworthiness, configuration control, affordability, maintainability, and supportability of high performance

43、aerospace systems (subsequently referred to as AHP) both during and after the transition to Pb-Free electronics. This document is intended for application to aerospace products; however, it may also be applied, at the discretion of the user, to other products with similar characteristics, e.g., low-

44、volume, rugged use environments, high reliability, long lifetime, and reparability. If other industries wish to use this document, they may substitute the name of their industry for the word “Aerospace” in this document. The guidelines may be used by the OEMs and maintenance facilities to implement

45、the methodologies they use to assure the performance, reliability, airworthiness, safety, and certifiability of their products, in accordance with Document GEIA-STD-0005-1, “Performance Standard for High Performance Electronic Systems Containing Pb-Free Solder.” This document also contains lessons l

46、earned from previous experience with Pb-Free aerospace electronic systems. The lessons learned give specific references to solder alloys and other materials, and their expected applicability to various operating environmental conditions. The lessons learned are intended for guidance only; they are n

47、ot guarantees of success in any given application.2. References Standards:GEIA-STD-0005-1, Performance Standard for Aerospace and High Performance Electronic Systems Containing Lead-Free SolderGEIA-STD-0005-2, Standard for Mitigating the Effects of Tin Whiskers in Aerospace and High Performance Elec

48、tronic Systems.GEIA-STD-0005-3, Performance Testing for Aerospace and High Performance Electronic Interconnects Containing Lead-Free Solder.GEIA-HB-0005-1, Program Management/Systems Engineering Guidelines For Managing The Transition To Lead-Free Electronics GEIA-HB-0005-3, Rework and Repair of Aero

49、space and High Performance Electronics Containing Lead Free SolderGEIA-HB-0005-4, Guidelines for Performing Reliability Assessment for Lead Free Assemblies used in Aerospace and High-Performance Electronic Applications GEIA-STD-0006, Requirements for Using Solder Dip to Replace the Finish on Electronic ComponentsGEIA-HB-0005-22ARINC Project Paper 671: Guidelines for Lead-free Soldering, Repair, and Rework, March 16, 2006.ASTM