Factors Affecting the Bulk Embrittlement of Pb-Free Solder Joints



This chapter mainly addresses the factors affecting the bulk embrittlement of Sn-based Pb-free solder joints, as this type of embrittlement may occur during the life cycle of these solder joints, depending on the requirements of their ‘mission profile’. The term ‘bulk embrittlement’ is used to describe brittle failures occurring in the solder bulk, in contrast to the brittle failures that occur in the intermetallic layers at the solder joint/bond pad interface. The factors affecting the bulk embrittlement of Sn-based Pb-free solder joints may be divided into ‘intrinsic’ and ‘extrinsic’. Examples of ‘intrinsic’ factors include the solder composition, crystal structure, and microstructure, while examples of ‘extrinsic’ factors include the temperature, strain rate, and constraint of the solder during service, as well as the cooling rate from the processing temperature. By understanding the mechanism of bulk solder embrittlement and the factors affecting it, one may try to find the ways to control it, especially when the conditions of the end application favour such type of embrittlement.


Fracture Toughness Solder Joint Impact Toughness Stable Crack Growth Notch Toughness 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



American Society for Testing and Materials


Body-centred cubic


Body-centred tetragonal


Back scattered electron


Crack-arrest temperature


Crack-mouth opening displacement


Crack-tip opening displacement


Charpy V-notch


Ductile-to-brittle transition temperature


Face-centred cubic


Fracture transition elastic temperature


Fracture transition plastic temperature


Hexagonal close-packed


Intermetallic(s) or intermetallic compound(s)


Load line displacement


Nil ductility temperature






Secondary electron


Scanning electron microscopy



Special Symbols


Figure adapted from the reference given in []


From “The Science and Engineering of Materials”, 5th edition, by Askeland and Phulé. © 2006 by Nelson. Reprinted with permission of Nelson, a division of Thomson Learning: www.tomsonrights.com. Fax: 800 730 2215


From “The Science and Engineering of Materials”, 1st edition, by Askeland. © 1984 by Wadsworth, Inc. Reprinted with permission of Brooks/Cole, a division of Thomson Learning: www.tomsonrights.com. Fax: 800 730 2215


From “Deformation and Fracture Mechanics of Engineering Materials”, 4th edition, by Hertzberg. © 1996 by John Wiley & Sons, Inc. Reprinted with permission of John Wiley and Sons, Inc


From “Fracture and Fatigue Control in Structures: Applications of Fracture Mechanics”, 3rd edition, by Barsom and Rolfe. © 1999 by ASTM International. Reprinted with permission of ASTM International


Reproduced with permission of Emerald Group Publishing Ltd. © 2000 by MCB University Press



The author would like to acknowledge certain persons, whose comments improved the quality of this text. These persons are listed in alphabetical order:

Dr. Dag Andersson (IVF, Sweden),

Prof. Ingrid De Wolf (imec, Belgium),

Dr. Paul Michelis (IMMG, Greece),

Prof. Marc Seefeldt (Department MTM, K. U. Leuven, Belgium),

Dr. Geert Willems (imec, Belgium).

The author also wishes to acknowledge the financial support provided by IWT (Flemish Government) in the framework of the ALSHIRA (Aspects of Lead-Free Soldering for High-Reliability Applications) Project. Last but not least, the author would like to thank Dr. B. Vandevelde, Mr. P. Limaye, and Mr. F. Duflos from imec, as well as Prof. B. Verlinden and Mr. W. Maurissen from the Department MTM of the Katholieke Universiteit Leuven (K. U. Leuven), for their collaboration on the research related with the embrittlement of Pb-free solder alloys.


  1. 1.
    Barsom JM, Rolfe ST (1999) Fracture and fatigue control in structures: applications of fracture mechanics, 3rd edn. ASTM Man Ser: MNL41, ASTM Int, West Conshohocken, USACrossRefGoogle Scholar
  2. 2.
    Hertzberg RW (1996) Deformation and fracture mechanics of engineering materials, 4th edn. Wiley, New York, USAGoogle Scholar
  3. 3.
    Hosford WF (2005) Mechanical behavior of materials, 1st edn. Cambridge University Press, New York, USAMATHGoogle Scholar
  4. 4.
    Hurlich A (1968) Low temperature metals. In: Prodell AG (ed) Proc 1968 summer study supercond devices accel, pp 311–325Google Scholar
  5. 5.
    Callister WD Jr (2000) Materials science and engineering: an introduction, 5th edn. Wiley, New York, USAGoogle Scholar
  6. 6.
    Reed-Hill RE, Abbaschian R (1994) Physical metallurgy principles, 3rd edn. PWS Publishing Company, Boston, USAGoogle Scholar
  7. 7.
    Askeland DR, Phulé PP (2006) The science and engineering of materials, 5th edn. Nelson, Toronto, CanadaGoogle Scholar
  8. 8.
    http://www.key-to-steel.com. Accessed 28 July 2008
  9. 9.
    Askeland DR (1984) The science and engineering of materials, 1st edn. Brooks/Cole, Monterey, USAGoogle Scholar
  10. 10.
    ASTM E 23-06 (2006) Standard test methods for notched bar impact testing of metallic materials. ASTM IntGoogle Scholar
  11. 11.
    Ratchev P, Loccufier T, Vandevelde B, Verlinden B, Teliszewski S, Werkhoven D, Allaert B (2005) A study of brittle to ductile fracture transition temperatures in bulk Pb-free solders. Proc EMPC 2005:248–252Google Scholar
  12. 12.
    Ratchev P, Vandevelde B, Verlinden B, Allaert B, Werkhoven D (2007) Brittle to ductile fracture transition in bulk Pb-free solders. IEEE Trans Compon Packag Technol 30:416–423CrossRefGoogle Scholar
  13. 13.
    Kariya Y, Gagg C, Plumbridge WJ (2000) Tin pest in lead-free solders. Solder Surf Mount Technol 13:39–40CrossRefGoogle Scholar
  14. 14.
    Metallography and Microstructures of Tin and Tin Alloys (2004) In: ASM Handb, vol 9: Metallography and Microstructures. ASM Int Google Scholar
  15. 15.
    Limaye P, Maurissen W, Lambrinou K, Duflos F, Vandevelde B, Allaert B, Hillaert J, Vandepitte D, Verlinden B (2007) Low-temperature embrittlement of lead-free solders in joint level impact testing. Proc EPTC 2007:140–151Google Scholar
  16. 16.
    Lambrinou K, Maurissen W, Limaye P, Vandevelde B, Verlinden B, De Wolf I (2009) A novel mechanism of embrittlement affecting the impact reliability of tin-based lead-free solder joints. J Electron Mater 38:1881–1895CrossRefGoogle Scholar
  17. 17.
    Ratchev P, Vandevelde B, Verlinden B (2005) Effect of the intermetallics particle size on the brittle to ductile fracture transition in a bulk Sn-4 wt%Ag-0.5 wt%Cu solder. CD-ROM Proc IPC/JEDEC 10th Int Conf Lead-Free Electron Compon AssemGoogle Scholar
  18. 18.
    Ganesan S, Pecht M (eds) (2006) Lead-free electronics. IEEE Press, Wiley, Hoboken, USAGoogle Scholar

Copyright information

© Springer-Verlag London Limited 2011

Authors and Affiliations

  1. 1.IMECLeuvenBelgium
  2. 2.SCK-CENMolBelgium

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