Non-cyanogen type electrolytic solution for plating gold

Abstract

A non-cyanogen type electrolytic solution, for plating gold, contains a gold salt as a supply source of gold and is added with a non-cyanogen type compound wherein the electrolytic plating solution is added with one selected from a group of thiouracil; 2-aminoethanethiol; N-methylthiourea, 3-amino-5-mercapto-1,2,4-triazole; 4,6-dihydroxy-2-mercaptopyrimidine; and mercapto-nicotinate; as a compound forming a complexing compound with gold. Chloroaurate or gold sulfite is preferably used as a gold salt.

1 . A gold plating method using a non-cyanogen type electrolytic solution, containing gold salt as a supply source of gold and added with a non-cyanogen type compound, wherein the electrolytic plating solution is added with one selected from a group of thiouracil; 2-aminoethanethiol; N-methylthiourea, 3-amino-5-mercapto-1,2,4-triazole; 4,6-dihydroxy-2-mercaptopyrimidine; and mercapto-nicotinate; as a compound forming a complexing compound with gold, and wherein the gold plating is carried out in a condition of a current density of 0.5 A/dm 2  or less.  
   
   
       2 . The gold plating method as set for  claim 1 , wherein chloroaurate or gold sulfite is used as gold salt.  
   
   
       3 . The gold plating method as set for  claim 2 , wherein non-cyanogen type compound has a deposition potential in a range from −0.4 Vvs.SCE to −0.8 Vvs.SCE.  
   
   
       4 . The gold plating method as set for  claim 3 , wherein non-cyanogen type compound is thiouracil or 2-aminoethanethiol.  
   
   
       5 . The gold plating method as set for  claim 3 , wherein a hydrogen ion concentration pH of the non-cyanogen type compound is 12 to 5 or is 8 to 5.