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US 5,182,009 AGranted
Plating process
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorSigeyuki Matumoto
Life of this patent
Estimating the term…
Abstract
Plating is achieved by selecting such a pH value that an increase of the weight composition of a metal to be plated and a decrease of the weight composition of said metal to be plated upon plating are compensated each other, and employing a plating solution of said selected pH value for plating.
Claims6
A method of plating a metal comprising the following steps:
- contacting said metal with a plating solution said plating solution having a pH and at least two metal ions, each metal ion having a concentration and said metal ions comprising at least one pH dependent metal ion, said pH dependent metal ion having a range of pH at which said pH dependent metal ion plates out of solution at a higher rate as the pH increases, and a range of concentration at which said pH dependent metal ion plates out of solution at a decreasing rate as the pH dependent metal ion concentration decreases;
- said pH and said pH dependent metal ion concentration selected such that during the period in which said metal is exposed to plating conditions, said plating solution has a range of pH, and a range of concentration of pH dependent metal ion at which such changes in pH and changes in pH dependent metal ion concentration cooperate to plate said pH dependent metal ion at a uniform rate;
- and imposing plating conditions for a period of time during which said pH and pH dependent metal ion concentration are within said range of pH and said range of concentration.
A method of plating a metal comprising the following steps:
- contacting said metal with a plating solution said plating solution having a pH and at least one metal ion, each metal ion having a concentration and said metal ions comprising at least one pH dependent metal ion, said pH dependent metal ion having a range of pH at which said pH dependent metal ion plates out of solution at a higher rate as the pH increases, and a range of concentration at which said pH dependent metal ion plates out of solution at a decreasing rate as the pH dependent metal ion concentration decreases;
- said pH and said pH dependent metal ion concentration selected such that during the period in which said metal is exposed to plating conditions, said plating solution has a range of pH, and a range of concentration of pH dependent metal ion at which such changes in pH and changes in pH dependent metal ion concentration cooperate to plate same pH dependent metal ion at a uniform rate;
- and imposing plating conditions for a period of time during which said pH and pH dependent metal ion concentration are within said range of pH and said range of concentration.
Dependencies are inferred from the claim text.