Low temperature tin-bismuth electroplating system

An electroplating system for the electrodeposition of a near eutectic tin-bismuth alloy on an electrically conductive substrate connected as a cathode to an electrical power source, the electroplating system comprising:

• plating tank means for containing an aqueous electroplating bath and for supporting the electrically conductive substrate;
• an aqueous electroplating bath contained in said plating tank means, said aqueous electroplating bath comprising a concentration of methane sulfonic acid, stannous ions and bismuth ions;
• at lest one bismuth anode immersed in said aqueous electroplating bath, said at least one bismuth anode connected to the electrical power source;
• container means for holding portions of said aqueous electroplating bath, said container means connected to said plating tank means by an inlet pipe and an outlet pipe;
• pump means for transferring said aqueous electroplating bath from said plating tank means to said container means via said inlet pipe;
• stannous ion replenishing means inserted into said container means for increasing the concentration of stannous ions in said aqueous electroplating bath;
• bismuth ion removal means for decreasing the concentration of bismuth ions in said aqueous electroplating bath;
• and
• shorting means coupled to said stannous ion replenishing means and said bismuth ion removal means for electrically connecting said stannous ion replenishing means to said bismuth ion removal means, whereby said concentration of said stannous ions and said bismuth ions is electrochemically maintained.