Semiconductor device and method for manufacturing the same

Abstract

Ferroelectric capacitors ( 42 ) are formed over a semiconductor substrate ( 10 ), then, a barrier film ( 46 ) directly covering the ferroelectric capacitors ( 42 ) is formed. Thereafter, wirings ( 56 a etc.) connected to the ferroelectric capacitors ( 42 ) are formed. Further, a barrier film ( 58 ) is formed at a position higher than the wirings ( 56 a etc.). In forming the barrier film ( 46 ), a film stack is formed, the film stack including at least two kinds of diffusion preventive films ( 46 a and 46 b ) having different components and preventing diffusion of hydrogen or water.

1 . A semiconductor device comprising: 
 a ferroelectric capacitor formed over a semiconductor substrate; and    a barrier film covering the ferroelectric capacitor,    wherein the barrier film is a film stack whose lower layer is one kind of film selected from a group consisting of an aluminum oxide film, an aluminum nitride film, and an aluminum oxynitride film, and whose upper layer is one kind of film selected from a group consisting of a titanium oxide film, a tantalum oxide film, a zirconium oxide film, and a tantalum nitride film.    
     
     
         2 . A semiconductor device comprising: 
 a ferroelectric capacitor formed over a semiconductor substrate; and    a barrier film formed over the ferroelectric capacitor,    wherein the barrier film is a film stack whose lower layer is one kind of film selected from a group consisting of an aluminum oxide film, an aluminum nitride film, and an aluminum oxynitride film, and whose upper layer is one kind of film selected from a group consisting of a titanium oxide film, a tantalum oxide film, a zirconium oxide film, and a tantalum nitride film.    
     
     
         3 . A semiconductor device comprising: 
 a ferroelectric capacitor formed over a semiconductor substrate;    a wiring connected to the ferroelectric capacitor; and    a barrier film formed at a position higher than the wiring,    wherein the barrier film is a film stack whose lower layer is one kind of film selected from a group consisting of an aluminum oxide film, an aluminum nitride film, and an aluminum oxynitride film, and whose upper layer is one kind of film selected from a group consisting of a titanium oxide film, a tantalum oxide film, a zirconium oxide film, and a tantalum nitride film.    
     
     
         4 . The semiconductor device according to  claim 1 , wherein a thickness of each of films composing of the film stack is from 1 nm to 10 nm.  
     
     
         5 . The semiconductor device according to  claim 3 , wherein the barrier film is the film stack directly covering the wiring.  
     
     
         6 . The semiconductor device according to  claim 3 , wherein at least a part of the wirings contains copper and has a damascene structure.  
     
     
         7 . The semiconductor device according to  claim 3 , further comprising an insulating film formed between the wiring and the barrier film and having a planarized surface, 
 wherein at least the barrier film is the film stack formed on the insulating film.    
     
     
         8 . The semiconductor device according to  claim 3 , wherein: 
 the wirings are formed in a plurality of wiring layers;    the barrier film is formed at one height position or more between the wiring layers; and    at least a part of the one barrier film or more is the film stack.    
     
     
         9 . A method for manufacturing a semiconductor device, comprising: 
 forming a ferroelectric capacitor over a semiconductor substrate;    forming a first barrier film directly covering the ferroelectric capacitor;    forming a wiring connected to the ferroelectric capacitor; and    forming a second barrier film over the wiring,    wherein at least one of the forming the first barrier film and the forming the second barrier film comprises the step of forming a film stack including at least two kinds of diffusion preventive films having different components and preventing diffusion of one of hydrogen and water.    
     
     
         10 . The method for manufacturing a semiconductor device according to  claim 9 , wherein as each of the diffusion preventive films, formed is one kind of film selected from a group consisting of an aluminum oxide film, a titanium oxide film, a tantalum oxide film, a zirconium oxide film, an aluminum nitride film, a tantalum nitride film, and an aluminum oxynitride film.  
     
     
         11 . The method for manufacturing a semiconductor device according to  claim 9 , wherein the forming the film stack comprises the steps of: 
 forming one kind of film selected from a group consisting of an aluminum oxide film, an aluminum nitride film, and an aluminum oxynitride film; and    forming, over the film, one kind of film selected from a group consisting of a titanium oxide film, a tantalum oxide film, a zirconium oxide film, and a tantalum nitride film.    
     
     
         12 . The method for manufacturing a semiconductor device according to  claim 9 , wherein a thickness of each of the diffusion preventive films is from 1 nm to 100 nm.  
     
     
         13 . The method for manufacturing a semiconductor device according to  claim 9 , wherein as the second barrier film, the film stack directly covering the wiring is formed.  
     
     
         14 . The method for manufacturing a semiconductor device according to  claim 9 , wherein: 
 as the first barrier film, the film stack is formed; and    as the second barrier film, the film stack directly covering the wiring is formed.    
     
     
         15 . The method for manufacturing a semiconductor device according to  claim 9 , wherein at least a part of the wirings is formed by a damascene method using copper.  
     
     
         16 . The method for manufacturing a semiconductor device according to  claim 15 , further comprising the step of using the second barrier film as an etching stopper film.  
     
     
         17 . The method for manufacturing a semiconductor device according to  claim 9 , further comprising the step of, between the forming the wiring and the forming the second barrier film, forming an insulating film having a planarized surface, 
 wherein as the second barrier film, the film stack is formed on the insulating film.    
     
     
         18 . The method for manufacturing a semiconductor device according to  claim 9 , wherein 
 the wirings are formed in a plurality of wiring layers,    the second barrier film is formed at one height position or more between the wiring layers, and    the film stack is formed as at least a part of the one or more second barrier film.    
     
     
         19 . The method for manufacturing the semiconductor device according to  claim 9 , wherein the forming the film stack comprises the steps of: 
 forming a first diffusion preventive film;    performing thermal treatment in an atmosphere containing oxygen; and    forming a second diffusion preventive film over the first diffusion preventive film.