Cyanide-free plating solutions for monovalent metals
AssigneeLeaRonal, Inc.
InventorsFred I. Nobel, William R. Brasch, Anthony J. Drago
Life of this patent
Estimating the term…
Abstract
A solution for use in electroplating which comprises at least one monovalent metal such as copper, silver or gold which is complexed by a thiosulfate ion; and a stabilizer of an organic sulfinate compound such as, for example, one having the formula R-SO.sub.2 -X wherein R is an alkyl, heterocyclic or aryl moiety and X is a monovalent cation. The stabilizer is present in an amount sufficient to stabilize the thiosulfate ion when the solution is operated at an acidic pH of less than 7. Also, the solution is substantially free of cyanide.
Claims35
A solution for use in electroplating which comprises:
- at least one monovalent metal which is complexed by an amount of a thiosulfate ion;
- and
- a stabilizer of an organic sulfinate compound in an amount sufficient to stabilize the thiosulfate ion when the solution is operated at an acidic pH of less than 7.
A solution for use in electroplating which comprises:
- at least one monovalent metal of copper, silver, gold or combinations thereof in an amount of between about 0.5 to 100 g/l which is complexed by a thiosulfate ion and wherein the thiosulfate ion and metal ion or ions are present in a molar ratio of about 1:1 to 3:1;
- and a stabilizer of an organic sulfinate compound in an amount of at least about 2 to 15 g/l to stabilize the thiosulfate ion when the solution is operated at an acidic pH of between about 4 and 6.
A metal plating bath which comprises:
- a solution of at least one monovalent metal ion which forms a thiosulfate complex;
- a solution soluble thiosulfate ion in an amount sufficient to form a complex with the metal ion or ions;
- and an organic sulfinate ion in an amount sufficient to stabilize the thiosulfate ion in the solution.
Dependencies are inferred from the claim text.