Method for producing a semiconductor device

Abstract

A producing method of the present invention includes (i) forming a wiring line above a semiconductor substrate, (ii) forming an insulating layer above the semiconductor substrate and the wiring line, (iii) forming an opening penetrating the insulating layer in the insulating layer with respect to a portion above the wiring line, (iv) forming a barrier layer whose surface is formed of a material A, so as to cover a surface of the insulating layer and an inner surface of the opening, (v) forming a metal layer made of a first metal on the barrier layer, and (vi) depositing a second metal inside the opening by a plating, thus forming a via plug containing the second metal. A rest potential P A of the material A with respect to the second metal is larger than a rest potential P M of the first metal with respect to the second metal.

What is claimed is:  
     
         1 . A method for producing a semiconductor device comprising processes of: 
 (i) forming a wiring line above a semiconductor substrate;    (ii) forming an insulating layer above the semiconductor substrate and the wiring line;    (iii) forming an opening penetrating the insulating layer in the insulating layer with respect to a portion above the wiring line;    (iv) forming a barrier layer whose surface is formed of a material A, so as to cover a surface of the insulating layer and an inner surface of the opening;    (v) forming a metal layer made of a first metal on the barrier layer; and    (vi) depositing a second metal inside the opening by a plating, thus forming a via plug containing the second metal;    wherein a rest potential P A  of the material A with respect to the second metal is larger than a rest potential P M  of the first metal with respect to the second metal.    
     
     
         2 . The method according to    claim 1   , wherein the barrier layer comprises a first layer and a second layer formed on the first layer; the second layer being made of the material A, and the first layer being made of a material B that has a smaller diffusion coefficient for the first metal and the second metal than the material A.  
     
     
         3 . The method according to    claim 1   , wherein the plating is an electroplating, and in the process (v), the metal layer is formed in a portion above the insulating layer and at a bottom of the opening alone.  
     
     
         4 . The method according to    claim 1   , wherein the material A is metal nitride, and the method further comprises a process of nitriding a surface of the barrier layer after the process (iv) and before the process (v).  
     
     
         5 . The method according to    claim 1   , wherein the first metal and the second metal are copper.  
     
     
         6 . The method according to    claim 1   , wherein the material A is titanium nitride.  
     
     
         7 . The method according to    claim 6   , wherein the material B is tantalum or tantalum nitride.