Patent ID: 8888903
Filing Date: 2014-11-18
Classification: C23C

Abstract:
1. An aqueous plating bath for electroless deposition of palladium and/or palladium alloys onto a copper or copper alloy surface, the plating bath comprising a. a source of palladium ions b. at least one nitrogenated complexing agent which is free of phosphorous c. a reducing agent selected from formic acid, formic acid derivatives, salts and mixtures of the aforementioned, hypophosphite compounds and amine-borane adducts and d. at least one organic stabilising agent which comprises 1 to 5 phosphonate residues wherein the concentration of the stabilising agent which comprises 1 to 5 phosphonate residues ranges from 0.1 to 100 mmol/l for stabilising agents comprising four and five phosphonate residues and from 50 to 500 mmol/l for stabilising agents comprising one, two and three phosphonate residues and wherein the at least one organic stabilising agent is selected from compounds according to formula (1) wherein R1 is selected from the group consisting of  hydrogen, methyl, ethyl, propyl and butyl; R2 is selected from the group consisting of  hydrogen, methyl, ethyl, propyl and butyl; R3 is selected from the group consisting of  hydrogen, methyl, ethyl, propyl and butyl; R4 is selected from the group consisting of  hydrogen, methyl, ethyl, propyl and butyl; n is an integer and ranges from 1 to 6; m is an integer and ranges from 1 to 6; o is an integer and ranges from 1 to 6; p is an integer and ranges from 1 to 6 and X is selected from the group consisting of hydrogen and a suitable counter ion.