Electroplating composition intended for coating a surface of a substrate with a metal

Abstract

The object of the present invention is an electroplating composition intended in particular for coating a copper-diffusion barrier layer in the fabrication of interconnects for integrated circuits. According to the invention, this composition comprises, in solution in a solvent: a source of copper ions, in a concentration of between 0.4 and 40 mM; at least one copper complexing agent chosen from the group comprising primary aliphatic amines, secondary aliphatic amines, tertiary aliphatic amines, aromatic amines, nitrogen heterocycles and oximes; the copper/complexing agent(s) molar ratio being between 0.1 and 2.5, preferably between 0.3 and 1.3; and the pH of the said composition being less than 7, preferably between 3.5 and 6.5.

1 . Electroplating composition intended in particular for coating a copper-diffusion barrier layer in the fabrication of interconnects for integrated circuits, characterized in that it comprises, in solution in a solvent: 
 a source of copper ions, in a concentration of between 0.4 and 40 mM;    at least one copper complexing agent chosen from the group comprising primary aliphatic amines, secondary aliphatic amines, tertiary aliphatic amines, aromatic amines, nitrogen heterocycles and oximes;    the copper/complexing agent(s) molar ratio being between 0.1 and 2.5, preferably between 0.3 and 1.3; and    the pH of the said composition being less than 7, preferably between 3.5 and 6.5.    
   
   
       2 . Electroplating composition according to  claim 1 , wherein the abovementioned solvent is chosen from water and hydroalcoholic mixtures.  
   
   
       3 . Electroplating composition according to  claim 1 , wherein the aforementioned source of copper ions is a copper salt, such as in particular copper sulphate, copper chlorate, copper nitrate or copper acetate, preferably copper sulphate.  
   
   
       4 . Electroplating composition according to  claim 1 , wherein the aforementioned copper complexing agent is chosen from: 
 primary aliphatic amines, in particular ethylamine, cyclohexylamine, ethylenediamine and cyclohexanediamine;    secondary aliphatic amines, in particular pyrrolidine;    tertiary aliphatic amines, in particular hydroxyethyldiethylamine and tetraethylenepentamine;    aromatic amines, in particular 1,2-diaminobenzene and 3,5-dimethylaniline;    nitrogen heterocycles, in particular pyridine, 2,2′-bipyridine, 8-hydroxyquinoline sulphonate, 1,10-phenanthroline, 3,5-dimethylpyridine and 2,2′-bipyrimidine; and    oximes, in particular dimethylglyoxime.    
   
   
       5 . Electroplating composition according to  claim 1 , wherein the aforementioned copper complexing agent is a nitrogen heterocycle chosen from pyridine, 2,2′-bipyridine, 8-hydroxyquinoline sulphonate, 1,10-phenanthroline, 3,5-dimethylpyridine and 2,2′-bipyrimidine.  
   
   
       6 . Electroplating composition according to  claim 1 , wherein it comprises a mixture of pyridine and 2,2′-bipyridine as copper complexing agents.  
   
   
       7 . Electroplating composition according to  claim 6 , wherein it comprises, in aqueous solution: 
 copper sulphate, with a concentration of between 0.4 and 40 mM;    a mixture of pyridine and 2,2′-bipyridine as copper complexing agents;    the copper/complexing agents molar ratio being between 0.3 and 1.3; and    the pH of the said composition being less than 7, preferably between 3.5 and 6.5.    
   
   
       8 . Use of an electroplating composition according to  claim 1  for coating a copper-diffusion barrier layer in the fabrication of interconnects for integrated circuits.