Plating bath and method for electroless deposition of nickel layers

Abstract

The present invention relates to aqueous plating bath compositions and methods for deposition of nickel and nickel alloys utilizing mixtures of stabilizing agents comprising ions of group IIIA metals and iodine containing, inorganic compounds in order to enhance bath stability.

1 . An aqueous plating bath composition for electroless deposition of nickel and nickel alloys, the composition comprising
 (i) a source of nickel ions,   characterized in that the aqueous plating bath composition further comprises   (ii) a mixture of stabilizing agents comprising
 a) at least one metal ion selected from indium ion and gallium ion, and 
 b) at least one selected from elementary iodine, iodide ion containing compounds, iodate ion containing compounds and periodate ion containing compounds. 
   
     
     
         2 . The aqueous plating bath composition according to  claim 1  wherein the indium ion is an indium(III) ion. 
     
     
         3 . The aqueous plating bath composition according to  claim 1  wherein the gallium ion is a gallium(III) ion. 
     
     
         4 . The aqueous plating bath composition according to  claim 1  wherein the stabilizing agent according to (ii)b) is selected from iodide ion containing compounds and iodate ion containing compounds. 
     
     
         5 . The aqueous plating bath composition according to  claim 1  wherein the concentration of the at least one metal ion according to (ii) a) ranges from 0.01 to 0.5 mmol/l. 
     
     
         6 . The aqueous plating bath composition according to  claim 1  wherein the concentration of the stabilizing agent according to (ii) b) ranges from 0.05 to 50.0 mmol/l. 
     
     
         7 . The aqueous plating bath composition according to  claim 1  wherein the source of nickel ions is selected from nickel sulfate, nickel chloride, nickel acetate, nickel methyl sulfonate, nickel sulfamate and mixtures thereof. 
     
     
         8 . The aqueous plating bath composition according to  claim 1  wherein the concentration of nickel ions ranges from 0.01 to 1 mol/l. 
     
     
         9 . The aqueous plating bath composition according to  claim 1  wherein the aqueous plating bath composition further comprises at least one complexing agent. 
     
     
         10 . The aqueous plating bath composition according to  claim 9  wherein the concentration of the at least one complexing agent ranges from 0.01 to 3.0 mol/l. 
     
     
         11 . The aqueous plating bath composition according to  claim 1  wherein the aqueous plating bath composition further comprises at least one reducing agent. 
     
     
         12 . The aqueous plating bath composition according to  claim 11  wherein the concentration of the at least one reducing agent ranges from 0.01 to 3.0 mol/l. 
     
     
         13 . The aqueous plating bath composition according to  claim 1  wherein the aqueous plating bath composition further comprises at least one alloying element wherein the at least one alloying element is selected from phosphorus, boron, titanium, vanadium, chromium, manganese, zirconium, niobium, molybdenum, hafnium, tantalum, tungsten, copper, silver, gold, aluminum, iron, cobalt, palladium, ruthenium, rhodium, osmium, iridium, platinum, zinc, cadmium, gallium, indium, tin, antimony, thallium, lead, and bismuth. 
     
     
         14 . A method for electroless deposition of nickel and nickel alloys comprising the steps of
 (A) providing a substrate,   (B) contacting the substrate with the aqueous plating bath composition according to  claim 1 ,   (C) and thereby depositing a nickel or nickel alloy onto the substrate.   
     
     
         15 . A method for stabilizing any electroless plating bath for deposition of nickel and nickel alloys, the method comprises the steps of
 (D) providing any electroless plating bath for deposition of nickel and nickel alloys, and   (E) adding a mixture of stabilizing agents, wherein the mixture of stabilizing agents comprises
 (ii)a) at least one metal ion selected from indium ion and gallium ion, and 
 (ii)b) at least one selected from elementary iodine, iodide ion containing compounds, iodate ion containing compounds and periodate ion containing compounds. 
   
     
     
         16 . The aqueous plating bath composition according to  claim 9  wherein the aqueous plating bath composition further comprises at least one reducing agent. 
     
     
         17 . The aqueous plating bath composition according to  claim 16  wherein the concentration of the at least one reducing agent ranges from 0.01 to 3.0 mol/l. 
     
     
         18 . The aqueous plating bath composition according to  claim 9  wherein the aqueous plating bath composition further comprises at least one alloying element wherein the at least one alloying element is selected from phosphorus, boron, titanium, vanadium, chromium, manganese, zirconium, niobium, molybdenum, hafnium, tantalum, tungsten, copper, silver, gold, aluminum, iron, cobalt, palladium, ruthenium, rhodium, osmium, iridium, platinum, zinc, cadmium, gallium, indium, tin, antimony, thallium, lead, and bismuth. 
     
     
         19 . The aqueous plating bath composition according to  claim 16  wherein the aqueous plating bath composition further comprises at least one alloying element wherein the at least one alloying element is selected from phosphorus, boron, titanium, vanadium, chromium, manganese, zirconium, niobium, molybdenum, hafnium, tantalum, tungsten, copper, silver, gold, aluminum, iron, cobalt, palladium, ruthenium, rhodium, osmium, iridium, platinum, zinc, cadmium, gallium, indium, tin, antimony, thallium, lead, and bismuth.