Semiconductor device and method for fabricating the same

Abstract

The semiconductor device comprises a first insulation film 26 formed over a semiconductor substrate 10 , first conductor plug 32 buried in a first contact hole 28 a formed down to a source/drain diffused layer 22 , a capacitor 44 formed over the first insulation film 26 , a first hydrogen diffusion preventing film 48 formed over the first insulation film 26 , covering the capacitor 44 , a second insulation film 50 formed over the first hydrogen diffusion preventing film and having the surface planarized, a second hydrogen diffusion preventing film 52 formed over the first hydrogen diffusion preventing film 26 and having the surface planarized, a second hydrogen diffusion preventing film 52 formed over the second insulation film 50 , second conductor plug 62 buried in a second contact hole 56 formed down to the lower electrode 38 or the upper electrode 42 of the capacitor 44 , a third conductor plug 62 buried in a third contact hole 58 formed down to the first conductor plug 32 , and an interconnection 64 connected to the second conductor plug 62 or the third conductor plug 62.

1 . A semiconductor device comprising:
 a capacitor formed over a semiconductor substrate and including a lower electrode, a dielectric film formed over the lower electrode and an upper electrode formed over the dielectric film;   an insulation film formed over the semiconductor substrate and the capacitor, a surface of the insulation film being planarized;   a flat barrier film formed over the insulation film, for preventing the diffusion of hydrogen and water,   the barrier film including a first film for preventing the diffusion of hydrogen and water and a second film for mitigating a stress due to the first film.   
     
     
         2 . A semiconductor device according to  claim 1 , wherein
 the barrier film includes a plurality of the first films, and   the second film is formed between said plurality of the first films.   
     
     
         3 . A semiconductor device according to  claim 1 , wherein
 the barrier film includes a plurality of the second films, and   the plural second films are formed respectively over and under the first films.   
     
     
         4 . A semiconductor device according to  claim 1 ,
 the first film is formed of a metal oxide.   
     
     
         5 . A semiconductor device according to  claim 4 , wherein
 the metal oxide is aluminum oxide or titanium oxide.   
     
     
         6 . A semiconductor device according to  claim 1 , wherein
 the second film is a silicon nitride film or silicon nitride oxide film.   
     
     
         7 . A semiconductor device according to  claim 1 , which further comprises
 an interconnection formed above the capacitor and electrically connected to the lower electrode or the upper electrode, and in which   the barrier film is formed between the capacitor and the interconnection.   
     
     
         8 . A semiconductor device according to  claim 1 , which comprises:
 a first interconnection formed above the capacitor and electrically connected to the lower electrode or the upper electrode; and   a second interconnection formed above the first   a second interconnection formed above the first interconnection, and in which   the barrier film is formed between the first interconnection and the second interconnection.   
     
     
         9 . A semiconductor device according to  claim 1 , which further comprises:
 a first interconnection formed above the capacitor and electrically connected to the lower electrode and the upper electrode;   a second interconnection formed above the first interconnection; and   a third interconnection formed above the second interconnection, and in which   the barrier film is formed between the second interconnection and the third interconnection.   
     
     
         10 . A semiconductor device according to  claim 1 , further comprising:
 a first interconnection formed above the capacitor and electrically connected to the lower electrode or the upper electrode;   a second interconnection formed above the first interconnection; and   a third interconnection formed above the second interconnection, and in which   the barrier films are formed respectively between the capacitor and the first interconnection, between the first interconnection and the second interconnection, and between the second interconnection and the third interconnection.   
     
     
         11 . A method for fabricating a semiconductor device comprising: a step of forming on a semiconductor substrate a capacitor including a lower electrode, dielectric film formed on the lower electrode and an upper electrode formed on the dielectric film; a step of forming an insulation film on the semiconductor substrate and the capacitor; the step of polishing a surface of the insulation film to planarize the surface of the insulation film; and a step of forming over the insulation film a barrier film for preventing the diffusion of hydrogen and water,
 the step of forming a barrier film including a step of forming a first film for preventing the diffusion of hydrogen and water and a step of forming a second film for mitigating a stress due to the first film.   
     
     
         12 . A method for fabricating a semiconductor device according to  claim 11 , further comprising, after the step of planarized the surface of the insulation film and before the step of forming the barrier film,
 the step of performing thermal processing in a nitrogen atmosphere to nitride the surface of the insulation film.   
     
     
         13 . A semiconductor device comprising:
 a capacitor formed on a semiconductor substrate and including a lower electrode, a dielectric film formed over the lower electrode and an upper electrode formed over the dielectric film;   an insulation film formed over the semiconductor substrate and the capacitor, a surface of the insulation film being planarized; and   a flat barrier film formed over the insulation film, for preventing the diffusion of hydrogen and water, the barrier film being formed of a plurality of first films for preventing the diffusion of hydrogen and water, which are laid one on another with a second film of a dielectric substance.   
     
     
         14 . A semiconductor device according to  claim 13 , wherein
 the first film is formed of a metal oxide.   
     
     
         15 . A semiconductor device according to  claim 14 , wherein
 the metal oxide is aluminum oxide or titanium oxide.   
     
     
         16 . A semiconductor device according to  claim 13 , wherein
 the second film is a silicon oxide film, a silicon nitride film or a silicon nitride oxide film.   
       film or a silicon nitride oxide film. 
     
     
         17 . A method for fabricating a semiconductor device comprising: a step of forming over a semiconductor substrate a capacitor including a lower electrode, a dielectric film formed over the lower electrode and an upper electrode formed over the dielectric film; a step of forming an insulation film over the semiconductor substrate and the capacitor; the step of polishing a surface of the insulation film to planarize the surface of the insulation film; and a step of forming over the insulation film a flat barrier film for preventing the diffusion of hydrogen and water,
 in the step of forming a barrier film, a plurality of first films for preventing the diffusion of hydrogen and water are laid one on another with a second film of a dielectric substance formed there between.   
     
     
         18 . A method for fabricating a semiconductor device according to  claim 17 , further comprising, after the step of planarized the surface of the insulation film and before the step of forming a barrier film,
 a step of performing thermal processing in a nitrogen atmosphere to nitride the surface of the insulation film.