Journal of Electronic Materials

, Volume 37, Issue 6, pp 880–886 | Cite as

Impact of Thermal Cycling on Sn-Ag-Cu Solder Joints and Board-Level Drop Reliability

  • Luhua Xu
  • John H. L. PangEmail author
  • Faxing Che

The electronic packaging industry uses electroless nickel immersion gold (ENIG) or Cu-organic solderability preservative (Cu-OSP) as a bonding pad surface finish for solder joints. In portable electronic products, drop impact tests induce solder joint failures via the interfacial intermetallic, which is a serious reliability concern. The intermetallic compound (IMC) is subjected to thermal cycling, which negatively affects the drop impact reliability. In this work, the reliability of lead-free Sn-3.0Ag-0.5Cu (SAC) soldered fine-pitch ball grid array assemblies were investigated after being subjected to a combination of thermal cycling followed by board level drop tests. Drop impact tests conducted before and after thermal aging cycles (500, 1000, and 1500 thermal cycles) show a transition of failure modes and a significant reduction in drop durability for both SAC/ENIG and SAC/Cu-OSP soldered assemblies. Without thermal cycling aging, the boards with the Cu-OSP surface finish exhibit better drop impact reliability than those with ENIG. However, the reverse is true if thermal cycle (TC) aging is performed. For SAC/Cu-OSP soldered assemblies, a large number of Kirkendall voids were observed at the interface between the intermetallic and Cu pad after thermal cycling aging. The void formation resulted in weak bonding between the solder and Cu, leading to brittle interface fracture in the drop impact test, which resulted in significantly lower drop test lifetimes. For SAC/ENIG soldered assemblies, the consumption of Ni in the formation of NiCuSn intermetallics induced vertical voids in the Ni(P) layer.


Drop impact thermal cycling intermetallic compound Kirkendall void Pb-free solder ball grid array 


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  1. 1.
    D.Y.R. Chong, F.X. Che, J.H.L. Pang, K. Ng, J.Y.N. Tan, T.H. Low, Microelectron. Reliab. 46, 1160 (2006)CrossRefGoogle Scholar
  2. 2.
    T.T. Mattila, J.K. Kivilahti, J. Electron. Mater. 35, 250 (2006)CrossRefGoogle Scholar
  3. 3.
    A. Sharif, Y.C. Chan, J. Alloy Compd. 393, 135 (2005)CrossRefGoogle Scholar
  4. 4.
    K. Zeng, K.N. Tu, Mater. Sci. Eng. R 38, 55 (2002)CrossRefGoogle Scholar
  5. 5.
    K. N. Tu, K. Zeng, Mater. Sci. Eng. R 34, 1 (2001)CrossRefGoogle Scholar
  6. 6.
    L.H. Xu, J.H.L. Pang, K.H. Prakash, T.H. Low, IEEE Trans. Compon. Pack. Technol. 28, 408 (2005)CrossRefGoogle Scholar
  7. 7.
    J.H.L. Pang, L.H. Xu, X.Q. Shi, W. Zhou, S.L. Ngoh, J. Electron. Mater. 33, 1219 (2004)CrossRefGoogle Scholar
  8. 8.
    P.T. Vianco, J.J. Stephens, J.A. Rejent, IEEE Trans. Compon. Pack. A 20, 478 (1997)CrossRefGoogle Scholar
  9. 9.
    J.H.L. Pang, T.H. Low, B.S. Xiong, L.H. Xu, C.C. Neo, Thin Solid Films 462, 370 (2004)CrossRefGoogle Scholar
  10. 10.
    L.H. Xu, J.H.L. Pang, J. Electron. Mater. 35, 2107 (2006)CrossRefGoogle Scholar
  11. 11.
    L.H. Xu, J.H.L. Pang, Thin Solid Films. 504, 362 (2006)CrossRefGoogle Scholar
  12. 12.
    C.L. Yeh, Y.S. Lai, J. Electron, Mater. 35, 1892 (2006)CrossRefGoogle Scholar
  13. 13.
    T.T. Mattila, J.K. Kivilahti, J. Electron. Mater. 34, 969 (2005)CrossRefGoogle Scholar
  14. 14.
    H.K. Kim, K.N. Tu, Phys. Rev. B 53, 16027 (1996)CrossRefGoogle Scholar
  15. 15.
    K.N. Tu, F. Ku, T.Y. Lee, J. Electron. Mater. 30, 1129 (2001)CrossRefGoogle Scholar
  16. 16.
    K. Zeng, R. Stierman, K.N. Tu, J. Appl. Phys. 97, 024508 (2005)CrossRefGoogle Scholar
  17. 17.
    T.C. Chiu, K. Zeng, R. Stierman, and D. Edwards, Proceeding of 54th ECTC, IEEE (New York, 2004), pp.␣1256–1263Google Scholar
  18. 18.
    F. Gao, H. Nishikawa, T. Takemoto, J. Electron. Mater. 37, 45 (2008)CrossRefGoogle Scholar
  19. 19.
    S.J. Wang, H.J. Kao, C.Y. Liu, J. Electron. Mater. 33, 1130 (2004)CrossRefGoogle Scholar
  20. 20.
    J. H. Lau and Y.H. Pao, Solder Joint Reliability of BGA, CSP, Flip Chip and Fine Pitch SMT Assemblies (McGraw-Hill, 1997), pp. 123–125Google Scholar

Copyright information

© TMS 2008

Authors and Affiliations

  1. 1.School of Mechanical & Aerospace EngineeringNanyang Technological UniversitySingaporeSingapore

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