Ammonia-free deposition of copper by disproportionation
First Claim
1. A process for the deposition of metallic copper on a catalytically activated surface comprising providing cupric ions in aqueous solution, adding to said cupric ions an ammonia-free reducer to rapidly reduce said cupric ions to cuprous hydroxide, and thereafter effecting disproportionation of the resultant cuprous hydroxide to bring about the deposition of metallic copper principally on said surface.
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Accused Products
Abstract
An ammonia-free reducer is added to cupric ions to achieve reduction to cuprous hydroxide in a process for the deposition of metallic copper on a catalytically activated surface by rapidly reducing cupric ions in aqueous solution to cuprous hydroxide, without substantial reduction to elemental or metallic copper, and thereafter effecting controlled disproportionation of the resultant cuprous hydroxide to bring about the deposition of metallic copper. The ammonia-free reducer is preferably hydroxylamine or its salts in the presence of a water soluble alkali metal- or alkaline earth metal- hydroxide, more preferably sodium hydroxide. The process of reduction of cupric ions is further effected by adding to the solution an antiagglomerating agent for controlling the dispersion of the cuprous hydroxide, preferably a polyol such as sorbose or invert sugar. The process of disproportionation of the cuprous hydroxide is further effected by adding an activator comprising a hydroxycarboxylic acid or salt thereof, preferably citric acid or malic acid with sulfuric acid, to bring about the deposition of metallic copper principally on the catalytically activated surface, wherein the hydroxycarboxylic acid or salt activator is present in solution in an amount no greater than about one mole per mole of cuprous hydroxide.
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Citations
43 Claims
- 1. A process for the deposition of metallic copper on a catalytically activated surface comprising providing cupric ions in aqueous solution, adding to said cupric ions an ammonia-free reducer to rapidly reduce said cupric ions to cuprous hydroxide, and thereafter effecting disproportionation of the resultant cuprous hydroxide to bring about the deposition of metallic copper principally on said surface.
- 11. A process for the deposition of metallic copper on a catalytically activated surface by providing cupric ions in aqueous solution, adding a substantially ammonia-free reducer to rapidly reduce said cupric ions in aqueous solution substantially completely to cuprous hydroxide, and thereafter effecting disproportionation of the resultant cuprous hydroxide by adding an activator comprising a hydroxycarboxylic acid or salt thereof, which activator brings about the deposition of metallic copper principally on said catalytically activated surface, said hydroxycarboxylic acid or salt activator being present in solution in an amount no greater than about one mole per mole of cuprous hydroxide.
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22. A system for depositing copper on a substrate by disproportionation of cuprous ions comprising the combination of:
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an aqueous solution containing cupric ions, an aqueous, ammonia-free cupric reducer solution containing a nitrogenous compound in a minimum concentration of about 25 g/l for reducing the cupric ions to a cuprous state, an aqueous alkali metal or alkaline earth metal solution for precipitating cuprous ions as a cuprous precipitate, and an aqueous activator solution containing a hydroxycarboxylic acid or salt thereof, an amine, or a mineral acid in combination with a hydroxycarboxylic acid or salt or amine, for disproportionation of the cuprous precipitate and deposition of copper on a substrate. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30, 31)
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32. A system for depositing copper on a substrate by disproportionation of cuprous ions comprising the combination of:
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an aqueous solution containing cupric ions, a substantially ammonia-free cupric reducer solution containing a nitrogenous compound in a minimum concentration of about 25 g/l for reducing the cupric ions to a cuprous state, an aqueous alkali metal or alkaline earth metal hydroxide solution for precipitating cuprous ions as cuprous hydroxide, and an aqueous activator solution containing a hydroxycarboxylic acid or salt thereof, said hydroxycarboxylic acid or salt thereof being present in an amount no greater than about one mole per mole of cuprous hydroxide, for disproportionation of the cuprous hydroxide and deposition of copper on a substrate. - View Dependent Claims (33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43)
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Specification