Semiconductor device and method for manufacturing the same

Abstract

A barrier metal that can be used in a semiconductor is to be made extremely thin. Further, the manufacturing steps of a semiconductor device are shortened to reduce its manufacturing cost. An insulating layer (e.g., a thermal nitride layer 10 ) with good step coverage formed on a surface of a conductor film such as lower electrodes 9 and 9 a of a capacitor on a semiconductor substrate is transformed into a reformed layer 11, which serves as a conductive barrier layer. Alternatively, the insulating layer formed on the surface of the insulating layer on the semiconductor substrate is totally or partially reformed into the conductive barrier layer. This reforming process is conducted by heating the above-mentioned semiconductor substrate at a predetermined temperature and, applying a plasma-excited high melting-point metal onto the surface of the above-mentioned insulating layer. This high melting-point metal may be Ti, Ta, Ni, Mo, W or the like.

What is claimed is:  
     
         1 . A semiconductor device comprising a conductive barrier layer formed on a semiconductor substrate; said conductive barrier layer has been reformed from an insulating layer.  
     
     
         2 . The semiconductor device according to  claim 1 , wherein said conductive barrier layer is formed on a surface of a conductor film on said semiconductor substrate.  
     
     
         3 . The semiconductor device according to  claim 1 , wherein said conductive barrier layer is formed on a surface of an insulator film on said semiconductor substrate, and said insulating layer has been totally or partially transformed into said conductive barrier layer.  
     
     
         4 . The semiconductor device according to  claim 1 , wherein said insulating layer is a silicon nitride film, and said conductive barrier layer is a metal compound of a high melting-point metal, a silicon (Si) and nitrogen (N).  
     
     
         5 . The semiconductor device according to  claim 4 , wherein said high melting-point metal is titanium (Ti), tantalum (Ta), nickel (Ni), molybdenum (Mo), or tungsten (W).  
     
     
         6 . The semiconductor device according to  claim 1 , wherein said insulating layer is a silicon nitride film, and said conductive barrier layer has a Ti—Si—N composition of 25-35 atomic percent of Ti, 30-40 atomic percent of Si, and 30-40 atomic percent of N.  
     
     
         7 . The semiconductor device according to  claim 2 , wherein said conductor film forms a lower electrode of a capacitor of said semiconductor device; 
 a dielectric film of said capacitor is formed as adhered to said conductive barrier layer; and    an upper electrode of said capacitor is formed on said dielectric film.    
     
     
         8 . The semiconductor device according to  claim 7 , wherein said dielectric film is composed of a tantalum oxide film, a strontium titanate film, a barium-strontium titanate film, or lead zirconate titanate film.  
     
     
         9 . The semiconductor device according to  claim 3 , wherein said insulator film constitutes an inter-layer insulator film of said semiconductor device; 
 said conductive barrier layer is formed on a side wall of a wiring line trench formed in a predetermined region of said inter-layer insulator film; and    a metal material is filled in said wiring line trench via said conductive barrier layer, to thereby form a trench wiring line in said inter-layer insulator film.    
     
     
         10 . The semiconductor device according to  claim 9 , wherein said metal material is copper (Cu).  
     
     
         11 . A method for manufacturing a semiconductor device, comprising the steps of: 
 forming an insulating layer on a semiconductor substrate; and    applying an active species of a high melting-point metal to a surface of said insulating layer under a condition of heating said semiconductor substrate to reform said insulating layer into a conductive barrier layer.    
     
     
         12 . The method for manufacturing the semiconductor device according to  claim 11 , wherein said conductive barrier layer is formed on a surface of a conductor film on said semiconductor substrate.  
     
     
         13 . The method for manufacturing the semiconductor device according to  claim 11 , wherein said conductive barrier layer is formed on a surface of an insulator film on said semiconductor substrate, and said insulating layer has been totally or partially transformed into said conductive barrier layer.  
     
     
         14 . The method for manufacturing the semiconductor device according to  claim 12 , wherein said conductor film is a polycrystalline silicon film of a lower electrode of a capacitor of a semiconductor device on a semiconductor substrate, and said insulating layer is a silicon nitride layer provided by thermal nitridation of the surface of said polycrystalline silicon film.  
     
     
         15 . The method for manufacturing the semiconductor device according to  claim 13 , wherein said insulator film is an inter-layer insulator film formed on a semiconductor substrate and forming a wiring line trench therein; said insulating layer covers an inner wall of said wiring trench; and a metal material fills said wiring line trench via said conductive barrier layer.  
     
     
         16 . The method for manufacturing the semiconductor device according to  claim 11 , wherein said active species of said high melting point metal is produced by plasma-exciting or by photo-exciting a halogen compound of said high melting-point metal.  
     
     
         17 . The method for manufacturing the semiconductor device according to  claim 16 , wherein said high melting-point metal is titanium (Ti), tantalum (Ta), nickel (Ni), molybdenum (Mo), or tungsten (W).  
     
     
         18 . The method for manufacturing the semiconductor device according to  claim 16 , wherein said insulating layer is a silicon nitride film, and said compound of said high melting point metal is titanium tetrachloride.  
     
     
         19 . The method for manufacturing the semiconductor device according to  claim 11 , wherein a heating temperature for said semiconductor substrate is set at 500° C. or higher.