Tin-silver-copper plating solution, plating film containing the same, and method for forming the plating film
AssigneeShinryo Electronics Co., Ltd.
InventorsHiromi Sonoda, Katsuji Nakamura
Life of this patent
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Abstract
An electrolytic plating method, including: preparing a plating solution including water which is a primary medium, a sulfonic acid, and tin, copper, and silver ions, and a complexing agent, concentrations of the sulfonic acid, and tin, copper, and silver ions being 0.5 to 5 mol/L, 0.21 to 2 mol/L, 0.002 to 0.02 mol/L, and 0.01 to 0.1 mol/L, respectively, a mole ratio of the silver-ion concentration to the copper-ion concentration being in a range of 4.5 to 5.58; and separating a solution around a soluble anode containing 90 percent or more of tin from the plating solution on a cathode side by a non-ionic micro-porous membrane having a pore diameter of 0.01 to 0.05 μm and a thickness of 5 to 100 μm.
Claims15
An electrolytic plating method, comprising the steps of:
- preparing a plating solution comprising water which is a primary medium, a sulfonic acid, and tin, copper, and silver ions, and an organic complexing agent, concentrations of the sulfonic acid, and tin, copper, and silver ions being 0.5 to 5 mol/L, 0.21 to 2 mol/L, 0.002 to 0.02 mol/L, and 0.01 to 0.1 mol/L, respectively, a mole ratio of the silver-ion concentration to the copper-ion concentration being in a range of 4.5 to 5.58;
- separating a solution around a soluble anode containing 90 percent or more of tin from the plating solution on a cathode side by a non-ionic micro-porous membrane having a pore diameter of 0.01 to 0.05 μm and a thickness of 5 to 100 μm;
- and
- carrying out electrolytic plating on a plating object to be a cathode.
Dependencies are inferred from the claim text.