Improvements in the Process for Electrodeposition of Au-Sn Alloys


Nasim Morawej1*, Douglas G. Ivey1, and Siamak Akhlaghi2



1 Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB  T6G 2G6

*Email:, Tel: 780-492-0588

2Micralyne Inc., 1911 - 94 Street, Edmonton, AB T6N 1E6


Keywords: Electrodeposition, Eutectic Solders, Electroplating Bath Stability, Gold, Tin



     An electroplating process has been developed to deposit gold rich, Au-Sn eutectic alloys from a single, non-cyanide, slightly acidic bath onto metallized semiconductor substrates. However, commercial exploitation is limited by plating bath lifetime and plating rates.  In this paper, the most effective factors influencing the lifetime and the plating rate are determined. Next, a statistical design approach (Box-Behnken) is taken to try to optimize the essential factors and, consequently, electrolyte lifetime and deposition rates.  A multiple response optimizer using commercial software can then be used to analyze the data to determine the optimal combination of solution components to both improve the stability and the plating rate.



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