1、 GEIA ENGINEERING BULLETIN GEIA-HB-0005-2 Technical Guidelines for Aerospace and High Performance Electronic Systems Containing Lead-free Solder and inishes FGEIA-HB-0005-2 November 2007 GOVERNMENT ELECTRONICS AND INFORMATION TECHNOLOGY ASSOCIATION A Sector of the Electronic Industries Alliance Copy
2、right Government Electronics 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 management/systems engineering gu
3、idelines (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 handbook (GEIA-HB-0005-3) an
4、d 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 performance industry documents. I
5、ntroduction The 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 electrical systems, the followi
6、ng variations to established practice will need to be considered: Components and printed circuit boards will need to be able to withstand higher manufacturing process temperatures. Printed circuit boards will need to have robust solderable Pb-Free surface finishes. Manufacturing and inspection techn
7、iques are needed that yield repeatable reliability characteristics. At least initially, Pb-free alloys used within the equipment should be restricted to those that are compatible with Tin-Lead soldering systems. A maintenance strategy should be developed that will facilitate the support repair of ne
8、w 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 Copyright Government Electronics however, many of the methodol
9、ogies 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 high reliability electronic and electrical systems are either in pro
10、gress 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 issuance. It is not the goal of this document to provide technical g
11、uidance 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 becomes available. Further complicating matters are the facts that no sing
12、le 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 performance electronic service lives, any Pb-Free alloy must have pre
13、dictable 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 be considered very carefully before use. Although Pb-Free solder all
14、oys 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 solder applications. In addition, some applications are using the Sn-
15、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 attach and printed circuit board insulation systems are being introduced
16、 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 well. The higher melting point, greater creep resistance and higher st
17、rength 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 ensure that Pb-Free solder will perform adequately for their produc
18、ts. 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 joint composition. Therefore, one needs to establish what the accele
19、ration 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 factors. Thermal preconditioning prior to thermal cycling should be
20、 considered in Copyright Government Electronics however, it may also be applied, at the discretion of the user, to other products with similar characteristics, e.g., low-volume, rugged use environments, high reliability, long lifetime, and reparability. If other industries wish to use this document,
21、 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 the methodologies they use to assure the performance, reliability, airworthiness, safety, and certifiability of their products, in
22、 accordance with Document GEIA-STD-0005-1, “Performance Standard for High Performance Electronic Systems Containing Pb-Free Solder.” This document also contains lessons learned from previous experience with Pb-Free aerospace electronic systems. The lessons learned give specific references to solder
23、alloys and other materials, and their expected applicability to various operating environmental conditions. The lessons learned are intended for guidance only; they are not guarantees of success in any given application. 2. References Standards: GEIA-STD-0005-1, Performance Standard for Aerospace an
24、d High Performance Electronic Systems Containing Lead-Free Solder GEIA-STD-0005-2, Standard for Mitigating the Effects of Tin Whiskers in Aerospace and High Performance Electronic Systems. GEIA-STD-0005-3, Performance Testing for Aerospace and High Performance Electronic Interconnects Containing Lea
25、d-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 Aerospace and High Performance Electronics Containing Lead Free Solder GEIA-HB-0005-4, Guidelines for Performing Reliability Asse
26、ssment 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 Components Copyright Government Electronics March 1, 2006. Also published in The Proceedings of SMTA International Confe
27、rence, Rosemont, IL, September 24-28, 2006. 60 Woodrow, T.A., “JCAA/JG-PP Lead-Free Solder Project: -20 to +80 C Thermal Cycling Test”, SMTA International Conference Proceedings, Rosemont, IL, September 24-28, 2006. 61 Borgesen, P., 2005 Year End Report Unovis Area Array Consortium (formerly Univers
28、al Instruments Consortium) 62 Chung, C.K., Aspandiar, R., Leong, K.F., Tay, C.S., “The Interactions of Lead (Pb) in Lead Free Solder (Sn/Ag/Cu) System”, Electronics Components and Technology Conference Proceedings (2002) 63 Maire, O., Munier, C., Bousquet, S., Chastenet, C., Jeremias, M., “Backward
29、Compatibility of Lead-Free BGA : Microstructural Characterization and Reliability”, IPC Soldertec, Malmo, Sweden 2006. Copyright Government Electronics “Solders”; Electronic Materials Handbook, Volume 1, Packaging; ASM International (1989) 67 Marshall, J. (Lau, J., editor); Solder Joint Reliability,
30、 Theory and Applications; Van Nostrand Reinhold, 1992; p218. 68 W.J. Boettinger et. al, “Whisker and Hillock Formation on Sn, Sn-Cu and Sn-Pb Electrodeposites,“ Acta Materialia, Vol. 53, No. 19, November 2005. 69 Williams, M.E., Moon, K.-W., Boettinger, W.J., Josell, D., Deal, A.D., “Hillock and Whi
31、sker Growth on Sn and SnCu Electrodeposits on a Substrate not Forming Interfacial Compounds”, Journal of Electronic Materials Vol. 36, No.3 (2007) pp. 214-219. 70 Abbott, Romm, Lange; “A Nickel-Palladium-Gold Integrated Circuit Lead Finish and Its Potential for Solder-Joint Embrittlement”, Applicati
32、on Report SZZA031; Texas Instruments, 2001. 71 Finley, D. W, et. al., “Assessment of NiPd Finished Components for Surface Mount Assembly Applications”, Surface Mount International Conference Proceedings, (SMTA, Edina, MN), 1995 pp. 941 953. 72 Mason, J. F., “RoHS is here with 29 Exemptions, and Coun
33、ting”, EDN Magazine September 12, 2006. 73 Momokawa, Y., and Ishizuka, N., “Delamination by Reheating in SMD Solder Joint Using Lead-Free Solder,” NEC Res OSP Finish in J-STD-001D 112 “Lead Free: How Will IPC Standards Change?” IPC Designers Council Newsletter “Route”, September 2005. 113 Wilcoxon,
34、R. and Hillman, D., “Effects of Thermal Interface Material on Solder Joint Reliability”, SMTA International Conference Proceedings, 2003. 114 Woodrow, T. A., and Ledbury, E.A., “Evaluation of Conformal Coatings as a Tin Whisker Mitigation Strategy”, IPC/JEDEC 8th International Conference on Lead-Fre
35、e Electronic Components and Assemblies, San Jose, CA, April 18-20 (2005) 115 Woodrow, T.A. and Ledbury, E.A., “Evaluation of Conformal Coatings as a Tin Whisker Mitigation Strategy, Part II” SMTA International Conference Proceedings (2006) 116 Teghall, P.-E., and Dunn, B.D., “Assessment of the Relia
36、bility of Solder Joints to Ball and Column Grid Array Packages for Space Applications”, ESA STM 266, ESA Publication Division, Noordwijk, The Netherlands September 2001. 117 Wild, R., “Fatigue Properties of Solder Joints”, Supplement to the Welding Journal, November (1972) pp. 521 526. 118 Richardso
37、n, J.H., and Lasley, B.R., “Tin Whisker Initiated Vacuum Metal Arcing in Spacecraft Electronics“, Proceedings of the Government Microcircuit Applications Conference, Vol. 18, pp. 119 - 122, November 10 12, 1992. 119 Hwang, J.S., Implementing Lead-Free Electronics, McGraw-Hill Professional Engineerin
38、g, NY, NY, 2004. 120 Puttlitz. K., and Stalter, K., Handbook of Pb-Free Solder Technology for Microelectronic Assemblies, Marcel-Dekker, NY, NY 2004. 121 Lau, J. H., Wong, C.P., Lee, N.-C., Lee, S.W., Electronics Manufacturing: with Lead-Free, Halogen-Free, and Conductive-Adhesive Materials, McGraw-
39、Hill, NY, NY, 2003. 122 Parrish, M. “Lead Free Solder Process Compatibility”, Wiring Harness News, Nov/Dec 2002 123 Colfax, R., OKeefe, M. J., Amick, P., Kleine, D., Vetter, S., Murry, D., “Perspectives on Repaired Lead-Free Solder Joints”, IPC/APEX proceedings, February 2005. 124 Perez,M., OKeefe,
40、M., Colfax, R., Vetter, S., Murry, D., Smith, J., Kleine, D., and Amick, P., “Vibration Testing of Repaired Lead-Tin/Lead-Free Solder Joints,” ECTC Conf. 2006 125 OKeefe, M., et.al, “The Effect of Mechanical Vibration on Thermally Cycled, Lead-Free and Mixed Alloy Solder Joints,” IPC APEX Conference
41、 2007. 126 Gleason, J., Reynolds, C., Bath, J., Chu, Q., Kelly, M., Lyjak, K., Roubaud, P., “Pb-free Assembly, Rework and Reliability Analysis of IPC Class 2 Assemblies” IEEE Electronic Components and Technology Conference, June 2005. 127 McCall, P. “Lead-free Solder and the Rework Process”, Surface
42、 Mount Technology (SMT) Magazine, April 2006. 128 Donaldson, A., and Aspandiar, R., “Hot Air Lead-Free Rework of BGA Packages examples include circuit cards and wire harnesses. AR Acrylic resin conformal coating. CAF refers to Conductive Anodic Filaments that form in printed wiring boards. See IPC-T
43、M-650 Method 2.6.25. CALCE: The University of Maryland Center for Advanced Life Cycle Engineering (CALCE) consortium. CLCC refers to a Ceramic Leadless Chip Carrier electronic package. Critical item or function, if defective, will result in the systems inability to retain operational capability, mee
44、t primary objective, or affect safety. Creep refers to time dependent strain occurring under stress. CSAM refers to C-Mode scanning acoustic microscopy, which is a method for evaluating electronic packages for internal delamination using high frequency sound waves. CTE refers to the coefficient of t
45、hermal expansion of a material. PCB CTE (x-y) is measured in the direction in the plane of the piece-part mounting surface and is used to quantify the stresses in the solder joint arising from the differences in CTE between the piece-parts and the PCB during thermal cycling. CTE(z) is measured in th
46、e “thickness” direction and is typically used to quantify plated through hole stress. Customer refers to an entity or organization that (a) integrates a piece part, soldered assembly, unit, or system into a higher level system, (b) operates the higher level system, or (c) certifies the system for us
47、e. For example, this may include end item users, integrators, regulatory agencies, operators, original equipment manufacturers (OEMs), and subcontractors. Dicy Cure refers to the use of dicyandiamide (dicy), as a curing agent for epoxy resins. EM refers to electromigration of the PCB metallization.
48、Resistance to electromigration testing is typically performed between electrically biased conductors at elevated humidity and temperature. ENIG refers to Electroless Nickel Immersion Gold Printed Wiring Board Finish. Copyright Government Electronics or that a certain course of action is preferred bu
49、t not Copyright Government Electronics or that (in the negative form) a certain course of action is deprecated but not prohibited. SIR refers the Surface Insulation Resistance measurements performed on PCBs. These electrical resistance measurements are often performed after periods of humidity exposure. SMT refers to surface mount technology circuit card assembly technology SMTA refers to the Surface Mount Technology Association, with headquarters in Edina, MN. Sn-Cu solder or alloy refers to Pb-Free all
