Composition, use thereof and method for electrodepositing gold containing layers

Abstract

The present invention relates to a composition and method for electrodepositing gold containing layers using the composition and the use of mercapto-triazole compounds as anti-immersion additives. The composition contains a mercapto-triazole compound which acts as an anti-immersion additive. The composition and method are suited for depositing functional or hard gold or gold alloys that can be applied in the industry as contact material of electrical connectors for high reliability applications.

1 . An electroplating composition comprising
 (i) at least one source of gold ions, and   (ii) at least one mercapto-triazole or a salt thereof, wherein the at least one mercapto-triazole has the following general formulae (I) or (II):   
       
         
           
           
               
               
           
         
       
       wherein R 1 , R 4  are independently of each other hydrogen, linear or branched, saturated or unsaturated (C 1 -C 20 ) hydrocarbon chain, (C 8 -C 20 ) aralkyl group; 
       substituted or unsubstituted phenyl group, naphthyl group or carboxyl group; and 
       R 2 , R 3 , R 5 , R 6  are independently of each other —S—X, hydrogen, linear or branched, saturated or unsaturated (C 1 -C 20 ) hydrocarbon chain, (C 8 -C 20 ) aralkyl group; 
       substituted or unsubstituted phenyl group, naphthyl group or carboxyl group; and 
       X is hydrogen, (C 1 -C 4 ) alkyl group or a counter-ion selected from alkali metal ions, calcium ion, ammonium ion and quaternary amines, and 
       at least one of R 2  and R 3  is —S—X, and at least one of R 5  and R 6  is —S—X. 
     
     
         2 . The composition according to  claim 1 , wherein the at least one mercapto-triazole has the general formulae (I) or (II),
 wherein R 1 , R 4  are independently of each other hydrogen or a linear (C 1 -C 4 ) alkyl group, and   R 2 , R 3 , R 5 , R 6  are independently of each other —S—X, hydrogen or a linear (C 1 -C 4 ) alkyl group; and   X is hydrogen, a methyl group, an ethyl group, or a counter-ion selected from sodium ion and potassium ion; and   at least one of R 2  and R 3  is —S—X, and at least one of R 5  and R 6  is —S—X.   
     
     
         3 . The composition according to  claim 1 , wherein the at least one mercapto-triazole has a concentration ranging from 1 mg/l to 1 g/l. 
     
     
         4 . The composition according to  claim 1 , further comprising at least one source of alloying metal ions, wherein the metal of the alloying metal ions is selected from cobalt, nickel and iron. 
     
     
         5 . The composition according to  claim 1 , further comprising complexing agents for gold ions. 
     
     
         6 . The composition according to  claim 1 , further comprising at least one brightening agent selected from pyridine and quinoline compounds. 
     
     
         7 . The composition according to  claim 1 , having a pH value between 1-6. 
     
     
         8 . A method comprising:
 (i) providing an electroplating composition according to  claim 1 ;   (ii) contacting a substrate with the composition; and   (iii) applying an electrical current between the substrate and at least one anode and thereby depositing a gold or gold alloy onto the substrate.   
     
     
         9 . The method according to  claim 8 , wherein the substrate is iron, nickel, copper or an alloy thereof. 
     
     
         10 . The method according to  claim 8 , wherein the substrate is an electrical connector. 
     
     
         11 . A method comprising:
 (i) providing a used gold or gold alloy electroplating composition;   (ii) adding a mercapto-triazole to the used gold or gold alloy electroplating composition for regenerating, wherein the mercapto-triazole is as defined in  claim 1 , and   (iii) contacting a substrate with the composition; and   (iv) applying an electrical current between the substrate and at least one anode and thereby depositing a gold or gold alloy onto the substrate.   
     
     
         12 . (canceled) 
     
     
         13 . The composition according to  claim 2 , wherein the at least one mercapto-triazole has a concentration ranging from 1 mg/l to 1 g/l. 
     
     
         14 . The composition according to  claim 2 , further comprising at least one source of alloying metal ions, wherein the metal of the alloying metal ions is selected from cobalt, nickel and iron. 
     
     
         15 . The composition according to  claim 2 , further comprising complexing agents for gold ions. 
     
     
         16 . The composition according to  claim 2 , further comprising at least one brightening agent selected from pyridine and quinoline compounds. 
     
     
         17 . A method comprising:
 (i) providing an electroplating composition according to  claim 2 ;   (ii) contacting a substrate with the composition; and   (iii) applying an electrical current between the substrate and at least one anode and thereby depositing a gold or gold alloy onto the substrate.   
     
     
         18 . The method according to  claim 17 , wherein the substrate is iron, nickel, copper or an alloy thereof. 
     
     
         19 . The method according to  claim 17 , wherein the substrate is an electrical connector. 
     
     
         20 . A method comprising:
 (i) providing a used gold or gold alloy electroplating composition;   (ii) adding a mercapto-triazole to the used gold or gold alloy electroplating composition for regenerating, wherein the mercapto-triazole is as defined in  claim 2 , and   (iii) contacting a substrate with the composition; and   (iv) applying an electrical current between the substrate and at least one anode and thereby depositing a gold or gold alloy onto the substrate.