Tin alloy electroplating bath and plating method using same

Abstract

A tin alloy electroplating bath, wherein the tin alloy electroplating bath includes (A) a soluble tin salt, (B) a soluble nickel salt and/or a soluble cobalt salt, (C) an oxycarboxylic acid or a salt thereof, (D) a nitrogen-containing heterocyclic unsaturated compound, and (E) a surfactant, and the pH of the tin alloy electroplating bath is 3 to 7.

1 . A tin alloy electroplating bath comprising:
 (A) a soluble tin salt;   (B) at least one of soluble nickel salts and soluble cobalt salts;   (C) an oxycarboxylic acid or a salt thereof;   (D) a nitrogen-containing unsaturated heterocyclic compound; and   (E) a surfactant, wherein   a pH of the tin alloy electroplating bath is 3 to 7.   
     
     
         2 . The tin alloy electroplating bath according to  claim 1 , wherein the nitrogen-containing unsaturated heterocyclic compound is a nitrogen-containing six-membered unsaturated heterocyclic compound or a nitrogen-containing five-membered unsaturated heterocyclic compound. 
     
     
         3 . The tin alloy electroplating bath according to  claim 1 , wherein the nitrogen-containing unsaturated heterocyclic compound includes at least one nitrogen-containing six-membered unsaturated heterocyclic compound selected from the group consisting of pyridines, derivatives of pyridines, pyrazines, and derivatives of pyrazines. 
     
     
         4 . The tin alloy electroplating bath according to  claim 1 , wherein the surfactant is selected from the group consisting of nonionic surfactants, anionic surfactants, cationic surfactants, amphoteric surfactants, and combinations of these surfactants. 
     
     
         5 . A method of electroplating an object with a tin alloy, comprising applying a DC current or a pulse current at a current density of 0.1 to 30 A/dm 2  to the object in the tin alloy electroplating bath according to  claim 1 .