Journal of Electronic Materials

, Volume 3, Issue 2, pp 353–369 | Cite as

Ultimate strength and morphological structure of eutectic bonds

  • F. G. Yost
Article

Abstract

Eutectic bonding is a technique commonly used in the electronics industry to fasten silicon chips to substrates coated with gold. The reverse process of bonding small gold tabs to large semiconductor substrates is also possible. Gold plated Kovar tabs have been bonded to a hot pressed silicon-germanium alloy (80 wt % Si) and to single crystals of silicon and germanium. The joining alloys used were gold-silicon (2 wt % Si) and gold-germanium (22 wt % Ge) which melt at 370‡C and 356‡C, respectively. Ultimate tensile loads have been measured and found to range from approximately 7.5 to l8 kilograms. Low tensile loads were associated with semiconductor surfaces which showed little evidence of dissolution, apparently protected by a surface oxide. A preliminary etch in 10% HF increased failure load considerably. Fracture then took place within the semiconductor material. Low strength bonds exhibit a lamellar eutectic structure, while high strength bonds exhibit lace-like grain boundary penetration of gold. Bonds on single crystals have considerable microstructural detail. Some show evidence of dendritic solidification, while others show evidence of eutectic solidification.

Key Words

Eutectic semiconductor bond etch oxide solidification 

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References

  1. 1.
    W. E. Kohl, Handbook of Materials and Techniques for Vacuum Devices, p. 377, Reinhold Publishing Corporation, New York (1967).Google Scholar
  2. 2.
    L. Bernstein, Semiconductor Products, 4, No. 7, 29, (1961).Google Scholar
  3. 3.
    L. Bernstein Semiconductor Products, 4, No. 8, 35, (1961).Google Scholar
  4. 4.
    M. H. Williamson, Proceedings of the Fourth Annual Microelectronics Symposium, “Molecular Concepts in Microelectronics,≓ I.E.E.E. publication, p. 6A-1 (1965).Google Scholar
  5. 5.
    J. A. Borders and J. N. Sweet, J. Appl. Phys., 43, 3803, (1972).CrossRefGoogle Scholar
  6. 6.
    P. Lukes, Surface Science, 30, 91, (1972).CrossRefGoogle Scholar
  7. 7.
    R. E. Oakley and G. A. Godber, Thin Solid Films, 9, 287, (1972).CrossRefGoogle Scholar
  8. 8.
    F. P. Fehlner, J. Electrochem. Soc., 119, 1723, (1972).CrossRefGoogle Scholar
  9. 9.
    W. Mehl, H. F. Gossenberger and E. Helpert, J. Electro-chem. Soc., 110, 239, (1963).CrossRefGoogle Scholar
  10. 10.
    R. C. Dorward and J. S. Kirkaldy, J. Electrochem. Soc., 116, 1284, (1969).CrossRefGoogle Scholar
  11. 11.
    J. I. Pankove, J. Appl. Phys., 28, 1054, (1957).CrossRefGoogle Scholar
  12. 12.
    G. A. Chadwick, Solidification, p. 99, American Society for Metals, Metals Park, Ohio, (1971).Google Scholar
  13. 13.
    M. E. Glicksman,, American Society for Metals, Metals Park, Ohio, p. 155, 1971.Google Scholar
  14. 14.
    R. D. Nasby, Sandia Laboratories Progress Report, SC-PR-72-0258, 21, (1972).Google Scholar
  15. 15.
    R. S. Wagner and W. C. Ellis, Trans. A.I.M.E., 233, 1053, (1965).Google Scholar
  16. 16.
    E. Philofsky, R. V. Ravi, J. Brooks, and E. Hall, J. Electrochem. Soc., 119, 527, (1972).CrossRefGoogle Scholar

Copyright information

© American Institute of Mining, Metallurgical, and Petroleum Engineers, Inc 1974

Authors and Affiliations

  • F. G. Yost
    • 1
  1. 1.Supporting Technology DivisionSandia LaboratoriesAlbuquerqueNew Mexico

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