Cyanide-free liquid composition for immersion gold plating

Abstract

A gold deposition accelerator for electroless gold plating comprising one or more alkali metal compound(s), wherein said alkali metal compound is not a compound comprising only sodium as an alkali metal, and said alkali metal compound is not only halide, only potassium sulfite, or only potassium sodium tartrate of an alkali metal, an electroless gold plating solution comprising said gold deposition accelerator, a gold plating method and a gold deposition accelerating method using the same and the like are provided.

1 . A gold deposition accelerator for electroless gold plating comprising one or more alkali metal compound(s), wherein said alkali metal compound is not a compound comprising only sodium as an alkali metal, and said alkali metal compound is not only halide, only potassium sulfite, or only potassium sodium tartrate of an alkali metal. 
     
     
         2 . An electroless gold plating solution comprising the gold deposition accelerator of  claim 1 , a water-soluble source of gold and a complexing agent. 
     
     
         3 . The electroless gold plating solution of  claim 2 , wherein the concentration of the alkali metal compound is 0.001 to 5 M on an alkali metal ion basis other than sodium. 
     
     
         4 . A gold deposition accelerator comprising a rubidium compound and/or cesium compound. 
     
     
         5 . An electroless gold plating solution comprising the gold deposition accelerator of  claim 4 , a water-soluble source of gold and a complexing agent. 
     
     
         6 . The electroless gold plating solution of  claim 5 , further comprising a sodium compound. 
     
     
         7 . The electroless gold plating solution of  claim 5 , comprising no cyanide compound. 
     
     
         8 . The electroless gold plating solution of  claim 5 , comprising an acid or a base as a pH regulator. 
     
     
         9 . A method of forming a gold plating film comprising a step of applying the electroless gold plating solution of  claim 5  on a surface of an electronic industrial component. 
     
     
         10 . A method of accelerating gold deposition in electroless gold plating comprising adding one or more alkali metal compound(s) in an electroless gold plating solution, wherein said alkali metal compound is not a compound comprising only sodium as an alkali metal, and said alkali metal compound is not only halide, only potassium sulfite, or only potassium sodium tartrate of an alkali metal. 
     
     
         11 . The method of  claim 10 , wherein the concentration of the alkali metal compound is 0.001 M to 5 M on an alkali metal ion basis other than sodium. 
     
     
         12 . A method of accelerating gold deposition in electroless gold plating by adding a rubidium compound and/or cesium compound. 
     
     
         13 . The method of  claim 12 , wherein the concentration of the rubidium compound and/or cesium compound is 0.001 M to 5 M on a rubidium ion and/or cesium ion basis. 
     
     
         14 . The electroless gold plating solution of  claim 2 , further comprising a sodium compound. 
     
     
         15 . The electroless gold plating solution of  claim 2 , comprising no cyanide compound. 
     
     
         16 . The electroless gold plating solution of  claim 2 , comprising an acid or a base as a pH regulator. 
     
     
         17 . A method of forming a gold plating film comprising a step of applying the electroless gold plating solution of  claim 2  on a surface of an electronic industrial component.