Semiconductor device having a capping layer including cobalt and method of fabricating the same

Abstract

A semiconductor device, and a method of fabricating the same, includes cobalt as a capping layer. An interconnection structure of the semiconductor device has an improved via resistance. In the semiconductor device, a single cobalt layer or a composite film including a cobalt layer and a titanium nitride layer is used as the capping layer of a metal layer.

1 . A semiconductor device, comprising: 
 a semiconductor substrate on which a structure including a transistor is formed;    a lower capping layer formed on the semiconductor substrate;    a metal layer formed on the lower capping layer;    an upper capping layer formed on the metal layer, covering substantially the entire surface of the metal layer and including at least a cobalt layer;    an interlayer insulating layer pattern formed on the upper capping layer and having a contact hole therethrough; and    a contact plug filling the contact hole of the interlayer insulating layer pattern.    
   
   
       2 . The semiconductor device of  claim 1 , wherein the upper capping layer is formed of one selected from a composite film including a cobalt layer and a titanium nitride layer stacked sequentially, and a cobalt layer.  
   
   
       3 . The semiconductor device of  claim 1 , wherein the lower capping layer is one selected from the group consisting of a composite film including a cobalt layer and a titanium nitride layer stacked sequentially, a cobalt layer, and a composite film including a titanium layer and a titanium nitride layer stacked sequentially.  
   
   
       4 . The semiconductor device of  claim 1 , wherein the metal layer is composed of aluminum.  
   
   
       5 . The semiconductor device of  claim 1 , wherein the interlayer insulating layer pattern is an oxide-based composite film.  
   
   
       6 . A semiconductor device comprising: 
 a semiconductor substrate on which a structure including a transistor is formed;    a lower capping layer formed on the semiconductor substrate and including at least one cobalt layer;    a metal layer formed on the lower capping layer;    an upper capping layer formed on the metal layer and covering substantially the entire surface of the metal layer;    an interlayer insulating layer pattern formed on the upper capping layer and having a contact hole therethrough; and    a contact plug filling the contact hole of the interlayer insulating layer pattern.    
   
   
       7 . The semiconductor device of  claim 6 , wherein the lower capping layer is one selected from the group consisting of a composite film including a cobalt layer and a titanium nitride layer stacked sequentially, and a cobalt layer.  
   
   
       8 . The semiconductor device of  claim 6 , wherein the upper capping layer is one selected from the group consisting of a composite film including a cobalt layer and a titanium nitride layer stacked sequentially, a cobalt layer, and a composite film including a titanium layer and a titanium nitride layer stacked sequentially.