Electrolytic tin plating solution and electrolytic tin plating method

Abstract

A plating solution and a plating method, which does not use a complexing agent and which provides favorable solder wetting properties and an extremely low coupling rate when electrolytic tin plating is performed, and particularly when electrolytic tin plating is performed using a barrel plating method.

1 . An electrolytic tin plating solution for chip components, comprising: (A) stannous ions, (B) acid, (C) N,N-dipolyoxyalkylene-N-alkyl amine, an amine oxide, or a blend thereof, and (D) an anti-sticking agent;
 wherein the pH is 1 or lower.   
   
   
       2 . The electrolytic tin plating solution for chip components according to  claim 1 , further comprising: (E) a plating uniformity improver. 
   
   
       3 . The electrolytic tin plating solution for chip components according to  claim 1 , further comprising: (F) one or more acrylic acid or acrylic acid derivative as expressed by the following General Formula (1); and (G) an antioxidant. 
     
       
         
         
             
             
         
       
     
     where R represents hydrogen or an alkyl group containing between 1 and 3 carbon atoms 
   
   
       4 . The electrolytic tin plating solution for chip components according to  claim 1 ,
 wherein the aforementioned N,N-dipolyoxyalkylene-N-alkyl amine is one or more compounds expressed by the following General Formula (2).   
     
       
         
         
             
             
         
       
     
     wherein R represents an alkyl group with between 6 and 28 carbon atoms, and w, x, y, and z each represent an integer between 0 and 30. However, the sum of w, x, y, and z is not 0. 
   
   
       5 . The electrolytic tin plating solution for chip components according to  claim 1 ,
 wherein the aforementioned amine oxide is one or more compounds expressed by the following General Formula (3).   
     
       
         
         
             
             
         
       
       where R represents an alkyl group, cycloalkyl group, or aryl group, and R′ represents a hydrogen atom, alkyl group, or cycloalkyl group. 
     
   
   
       6 . The electrolytic tin plating solution for chip components according to  claim 1 ,
 wherein the (D) anti-sticking agent is one or more compound selected from a group consisting of aromatic aldehydes and aromatic ketones.   
   
   
       7 . A method of plating chip components, comprising electrolytically tin plating chip components using an electrolytic tin plating solution comprising (A) stannous ions, (B) acid, (C) N,N-dipolyoxyalkylene-N-alkyl amine, an amine oxide, or a blend thereof, and (D) an anti-sticking agent; wherein the pH is 1 or less.