Method and apparatus for mitigating tin whisker growth on tin and tin-plated surfaces by doping tin with gold

Method and apparatus for mitigating tin whisker growth on tin and tin-plated surfaces by doping tin with gold

  • CN 105,378,151 B
  • Filed: 04/29/2014
  • Issued: 08/28/2020
  • Est. Priority Date: 07/05/2013
  • Status: Active Grant
First Claim
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1. A method of mitigating tin whisker growth on a surface of a substrate, comprising the steps of:

  • combining in a first volume a water-soluble gold-containing compound, water, a first complexing agent, and a second complexing agent by;

    preparing a first solution by adding an amount of the water-soluble gold-containing compound to the water,adding the first complexing agent to the first solution, andadding the second complexing agent to the first solution;

    combining a buffer, water, a water-soluble tin-containing compound, and a surfactant/leveling agent in a second volume separate from the first volume by;

    preparing a second solution comprising an amount of said buffer dissolved in said water,adding the water-soluble tin-containing compound to the second solution, andadding an amount of the surfactant/leveling agent to the second solution;

    forming a third solution by combining the first solution of the added first complexing agent and the added second complexing agent with the second solution of the added water-soluble tin-containing compound and the added amount of surfactant/leveling agent, wherein the third solution comprises a plurality of gold and tin ions in solution;

    immersing an anode electrode in the third solution,immersing a cathode substrate in the third solution, the cathode substrate comprising a cathode substrate surface;

    connecting the anode electrode and the cathode substrate to a power source capable of providing an electric current;

    turning on the power source to provide the current to the anode electrode, the cathode substrate, and the third solution; and

    co-depositing from the third solution an amount of gold and an amount of tin onto the cathode substrate surface to a gold concentration of 0.5 to 5% by weight;

    wherein the co-deposited amounts of gold and tin co-deposited on the cathode substrate surface provide a suitable surface for soldering; and

    wherein the tin whisker formation on the cathode substrate surface is mitigated.

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