Semiconductor device and manufacturing method thereof

Abstract

An insulation film ( 24 ) having a gradual inclination of a surface is formed by a high density plasma CVD method, an atmospheric pressure CVD method or the like, after a ferroelectric capacitor ( 23 ) is formed. Thereafter, an alumina film ( 25 ) is formed on the insulation film ( 24 ). According to the method, low coverage of the alumina film ( 25 ) does not become a problem, and the ferroelectric capacitor ( 23 ) is reliably protected.

1 . The semiconductor device, comprising:
 a semiconductor substrate;   a ferroelectric capacitor formed above said semiconductor substrate;   an insulation film directly covering said ferroelectric capacitor and having an inclination of its surface more gradual than an inclination of a surface of said ferroelectric capacitor;   a hydrogen diffusion prevention film formed on said insulation film and preventing diffusion of hydrogen to said ferroelectric capacitor;   a semiconductor element formed on said semiconductor substrate;   a pad formed above said semiconductor substrate and connected to said semiconductor element;   one wiring layer or two or more wiring layers formed between said semiconductor element and said pad; and   a water permeation prevention film formed between an uppermost wiring layer located at an uppermost position of said one wiring layer or two or more wiring layers, and preventing permeation of water to a lower layer side thereof.   
     
     
         2 . The semiconductor device according to  claim 1 , wherein said water permeation prevention film is one selected from a group consisting of an aluminum oxide film, a silicon nitride film and a silicon oxynitride film. 
     
     
         3 . A semiconductor device, comprising:
 a semiconductor substrate;   a semiconductor element formed on said semiconductor substrate;   a pad formed above said semiconductor substrate and connected to said semiconductor element;   one wiring layer or two or more wiring layers formed between said semiconductor element and said pad; and   a water permeation prevention film formed between an uppermost wiring layer located at an uppermost position of said one wiring layer or two or more wiring layers, and preventing permeation of water to a lower layer side thereof.   
     
     
         4 . The semiconductor device according to  claim 3 , further comprising an insulation film formed to cover said uppermost wiring layer by a high density plasma CVD method. 
     
     
         5 . The semiconductor device according to  claim 3 , wherein said water permeation prevention film is one selected from a group consisting of an aluminum oxide film, a silicon nitride film and a silicon oxynitride film. 
     
     
         6 . The semiconductor device according to  claim 3 , wherein thickness of said water permeation prevention film is 10 nm to 100 nm. 
     
     
         7 . The semiconductor device according to  claim 3 , further comprising a ferroelectric capacitor formed at any layer between said semiconductor substrate and said uppermost wiring layer. 
     
     
         8 . A manufacturing method of a semiconductor device, comprising the steps of:
 forming a ferroelectric capacitor above a semiconductor substrate;   forming an insulation film directly covering the ferroelectric capacitor and having an inclination of its surface more gradual than an inclination of a surface of the ferroelectric capacitor; and   forming a hydrogen diffusion prevention film preventing diffusion of hydrogen to the ferroelectric capacitor on the insulation film.   
     
     
         9 . The manufacturing method of the semiconductor device according to  claim 8 , wherein the insulation film is formed by a high density plasma CVD method. 
     
     
         10 . The manufacturing method of the semiconductor device according to  claim 9 , wherein temperature of the semiconductor substrate on forming the insulation film is set at 175° C. to 350° C. 
     
     
         11 . The manufacturing method of the semiconductor device according to  claim 8 , wherein one selected from a group consisting of a silicon oxide film doped with no impurity, a silicon oxynitride film, a silicon oxide film doped with fluorine, a silicon oxide film doped with phosphorus, and a silicon oxide film doped with boron and phosphorus is formed as the insulation film. 
     
     
         12 . The manufacturing method of the semiconductor device according to  claim 8 , wherein one selected from a group consisting of an aluminum oxide film, an aluminum oxynitride film, a tantalum oxide film and a titanium oxide film is formed as the hydrogen diffusion prevention film. 
     
     
         13 . The manufacturing method of the semiconductor device according to  claim 8 , wherein thickness of the hydrogen diffusion prevention film is made 10 nm to 100 nm. 
     
     
         14 . The manufacturing method of the semiconductor device according to  claim 8 , wherein the insulation film is formed by an atmospheric pressure CVD method or a plasma CVD method with tetra-ethyl ortho-silicate as a raw material. 
     
     
         15 . The manufacturing method of a semiconductor device according to  claim 14 , further comprising the step of performing plasma treatment using plasma of N 2  (nitrogen) or N 2 O (dinitrogen monoxide) for the insulation film, after said step of forming the insulation film. 
     
     
         16 . The manufacturing method of the semiconductor device according to  claim 15 , wherein in said step of performing the plasma treatment, temperature of an inside of a treatment chamber is set at 200° C. to 450° C. 
     
     
         17 . The manufacturing method of the semiconductor device according to  claim 12 , wherein the aluminum oxide film is formed by a physical vapor deposition method, an MOCVD method or a hydrolysis method. 
     
     
         18 . The manufacturing method of the semiconductor device according to  claim 17 , wherein a silicon oxide film or a silicon oxynitride film by a high density plasma CVD method or a plasma CVD method. 
     
     
         19 . The manufacturing method of the semiconductor device according to  claim 8 , wherein said step of forming the insulation film comprises the steps of:
 forming a silicon oxide film or a silicon oxynitride film by a plasma CVD method, and   forming a silicon oxide film doped with no impurity is formed by an atmospheric pressure CVD method with tetra-ethyl ortho-silicate as a raw material.   
     
     
         20 . The manufacturing method of the semiconductor device according to  claim 8 , further comprising the step of
 forming a semiconductor element on the semiconductor substrate before said step of forming the ferroelectric capacitor, and   further comprising the steps of, after said step of forming the hydrogen diffusion prevention film:   forming one wiring layer or two or more wiring layers above the ferroelectric capacitor;   forming a water permeation prevention film preventing permeation of water to a lower layer side above an uppermost wiring layer located at an uppermost position of the one wiring layer or two or more wiring layers; and   forming a pad connected to the semiconductor element above the water permeation prevention film.   
     
     
         21 . The manufacturing method of the semiconductor device according to  claim 20 , wherein one selected from a group consisting of an aluminum oxide film, a silicon nitride film and a silicon oxynitride film is formed as the water permeation prevention film. 
     
     
         22 . The manufacturing method of the semiconductor device according to  claim 8 , further comprising the steps of, after said step of forming the hydrogen diffusion prevention film:
 forming an interlayer insulation film on the hydrogen diffusion prevention film;   flattening the interlayer insulation film;   forming a contact hole reaching a part of the ferroelectric capacitor in the interlayer insulation film, the hydrogen diffusion prevention film and the insulation film;   performing annealing at 400° C. to 600° C. in atmosphere containing at least one kind of gas selected from a group consisting of oxygen and nitrogen for the ferroelectric capacitor; and   forming a wiring connected to the ferroelectric capacitor via the contact hole.   
     
     
         23 . A manufacturing method of a semiconductor device, comprising the steps of:
 forming a semiconductor element on a semiconductor substrate;   forming one wiring layer or two or more wiring layers above the semiconductor element;   forming a water permeation prevention film preventing permeation of water to a lower layer side above an uppermost wiring layer located at an uppermost position of the one wiring layer or two or more wiring layers; and   forming a pad connected to the semiconductor element above the water permeation prevention film.   
     
     
         24 . The manufacturing method of the semiconductor device according to  claim 23 , further comprising the step of forming an insulation film covering the uppermost wiring layer by a high density plasma CVD method, before said step of forming the water permeation prevention film. 
     
     
         25 . The manufacturing method of the semiconductor device according to  claim 23 , wherein one selected from a group consisting of an aluminum oxide film, a silicon nitride film and a silicon oxynitride film is formed, as the water permeation prevention film. 
     
     
         26 . The manufacturing method of the semiconductor device according to  claim 23 , wherein thickness of the water permeation prevention film is made 10 nm to 100 nm. 
     
     
         27 . The manufacturing method of the semiconductor device according to  claim 23 , further comprising the step of forming an insulation film covering the uppermost wiring layer by a plasma CVD method with tetra-ethyl ortho-silicate as a raw material, before said step of forming the water permeation prevention film. 
     
     
         28 . The manufacturing method of a semiconductor device according to  claim 23 , further comprising the steps of, before said step of forming the water permeation prevention film:
 forming a first insulation film covering the uppermost wiring layer by a plasma CVD method with tetra-ethyl ortho-silicate as a raw material;   flattening the first insulation film;   performing plasma treatment using plasma of N 2 O (dinitrogen monoxide) for the first insulation film;   forming a second insulation film on the first insulation film by a plasma CVD method with tetra-ethyl ortho-silicate as a raw material; and   performing plasma treatment using plasma of N 2 O (dinitrogen monoxide) for the second insulation film, and   further comprising the steps of, before said step of forming the pad:   forming a third insulation film on the water permeation prevention film by a plasma CVD method with tetra-ethyl ortho-silicate as a raw material; and   performing plasma treatment using plasma of N 2 O (dinitrogen monoxide) for the third insulation film.   
     
     
         29 . The manufacturing method of the semiconductor device according to  claim 23 , further comprising the step of forming a ferroelectric capacitor above the semiconductor substrate in parallel with said step of forming the one wiring layer or two or more wiring layers above the semiconductor element.