Advertisement

Journal of Applied Electrochemistry

, Volume 37, Issue 8, pp 899–904 | Cite as

Effects of K4Fe(CN)6 on electroless copper plating using hypophosphite as reducing agent

  • Xueping Gan
  • Yating Wu
  • Lei Liu
  • Wenbin HuEmail author
Original Paper

Abstract

K4Fe(CN)6 was used to improve the microstructure and properties of copper deposits obtained from hypophosphite baths. In electroless copper plating solutions using hypophosphite as the reducing agent, nickel ions (0.0038 M with Ni2+/Cu2+ mole ratio 0.12) was used to catalyze hypophosphite oxidation. However, the color of the copper deposits was dark or brown and its resistivity was much higher than that obtained in formaldehyde baths. The effects of K4Fe(CN)6 on the deposit composition, resistivity, structure, morphology and the electrochemical reactions of hypophosphite (oxidation) and cupric ion (reduction) have been investigated. The deposition rate and the resistivity of the copper deposits decreased significantly with the addition of K4Fe(CN)6 to the plating solution and the color of the deposits changed from dark-brown to copper-bright with improved uniformity. The nickel and phosphorus content in the deposits also decreased slightly with the use of K4Fe(CN)6. Smaller crystallite size and higher (111) plane orientation were obtained by addition of K4Fe(CN)6. The electrochemical current–voltage results show that K4Fe(CN)6 inhibited the catalytic oxidation of hypophosphite at active nickel sites and reduced the reduction reaction of cupric ions on the deposit surface by adsorption on the electrode. This results in lower deposition rate and a decrease in the mole ratio of NaH2PO2/CuSO4 consumed during plating.

Keywords

K4Fe(CN)6 Hypophosphite Electroless copper plating Copper deposits 

References

  1. 1.
    Kou SC, Hung A (2003) Plat Surf Finish 90(3):44Google Scholar
  2. 2.
    Deckert CA (1995) Plat Surf Finish 82(2):48Google Scholar
  3. 3.
    Deckert CA (1995) Plat Surf Finish 82(2):58Google Scholar
  4. 4.
    Li J, Kohl PA (2003) J Electrochem Soc 150(8):C558CrossRefGoogle Scholar
  5. 5.
    Cheng DH, Xu WY, Zhang ZY, Yiao ZH (1997) Met Finish 95(1):34CrossRefGoogle Scholar
  6. 6.
    Rangarajan J, Mahadevaiyer K, Gregory W (1989) U.S. Pat. 4,818,286Google Scholar
  7. 7.
    Hung A, Ohno I (1990) J Electrochem Soc 137(3):918CrossRefGoogle Scholar
  8. 8.
    Hung A, Chen KM (1989) J Electrochem Soc 136(1):72CrossRefGoogle Scholar
  9. 9.
    Vaskelis A, Norkus E, Jaciauskiene J (2002) J Appl Electrochem 32:297CrossRefGoogle Scholar
  10. 10.
    Li J, Kohl PA (2002) J Electrochem Soc 149(12):C631CrossRefGoogle Scholar
  11. 11.
    Li J, Hayden H, Kohl PA (2004) Electrochim Acta 49:1789CrossRefGoogle Scholar
  12. 12.
    Lin WH, Chang HF (1998) Surf Coat Technol 107:48CrossRefGoogle Scholar
  13. 13.
    Vaskelis A, Jaciauskiene J, Stalnioniene I, Norkus E (2006) J Electroanal Chem 600(1):6CrossRefGoogle Scholar
  14. 14.
    Cullity BD (1978) Elements of X-ray Diffraction. Addison-Wesley, LondonGoogle Scholar
  15. 15.
    Fierro JLF (1990) Spectroscopic characterization of heterogeneous catalysts, part: B. Elsevier, The NetherlandsGoogle Scholar
  16. 16.
    Patterson JC, O’Reilly M, Crean GM, Barrett J (1997) Microelectron Eng 33:65CrossRefGoogle Scholar
  17. 17.
    Tzeng SS, Chang FY (2001) Thin Solid Films 388:143CrossRefGoogle Scholar
  18. 18.
    Ohno I, Wakabayashi O, Haruyama S (1985) J Electrochem Soc 132:2323CrossRefGoogle Scholar
  19. 19.
    Paunovic M, Zeblisky R (1985) Plat Surf Finish 72(2):52Google Scholar
  20. 20.
    Hung A (1988) Plat Surf Finish 75(1):62Google Scholar

Copyright information

© Springer Science+Business Media, Inc. 2007

Authors and Affiliations

  1. 1.State Key Laboratory of Metal Matrix CompositesShanghai Jiao Tong UniversityShanghaiChina

Personalised recommendations