Manufacture method for semiconductor device capable of preventing reduction of ferroelectric film

Abstract

A ferroelectric capacitor is formed on a semiconductor substrate, the ferroelectric capacitor comprising a lower electrode, a ferroelectric film and an upper electrode stacked in an order recited. A first capacitor protective film of aluminum oxide having a thickness equal to or thicker than 30 nm is formed covering the ferroelectric capacitor. A first insulating film of silicon oxide is formed on the first capacitor protective film by chemical vapor deposition using high density plasma.

1 . A manufacture method for a semiconductor device comprising:
 forming a ferroelectric capacitor over a semiconductor substrate, the ferroelectric capacitor comprising a lower electrode, a ferroelectric film and an upper electrode stacked in an order recited;   forming a first capacitor protective film of aluminum oxide having a thickness equal to or thicker than 30 nm, the first capacitor protective film covering the ferroelectric capacitor; and   forming a first insulating film of silicon oxide on the first capacitor protective film by chemical vapor deposition using high density plasma.   
     
     
         2 . The manufacture method for a semiconductor device according to  claim 1 , further comprising:
 planarizing a surface of the first insulating film;   forming a second capacitor protective film of aluminum oxide on the planarized first insulating film;   forming a second insulating film of silicon oxide having a thickness equal to or thicker than 300 nm over the second capacitor protective film by plasma enhanced chemical vapor deposition using tetraethoxysilane-containing gas as source gas;   forming a first wiring of conductive material over the second insulating film; and   forming a third insulating film of silicon oxide over the second insulating film by chemical vapor deposition using high density plasma, the third insulating film covering the first wiring.   
     
     
         3 . The manufacture method for a semiconductor device according to  claim 1 , further comprising:
 planarizing a surface of the first insulating film;   forming a second capacitor protective film of aluminum oxide having a thickness equal to or thicker than 30 nm over the planarized first insulating film;   forming a first wiring of conductive material over the second capacitor protective film; and   forming a third insulating film of silicon oxide over the second capacitor protective film by chemical vapor deposition using high density plasma, the third insulating film covering the first wiring.   
     
     
         4 . The manufacture method for a semiconductor device according to  claim 1 , further comprising:
 forming a first wiring of conductive material over the first insulating film;   forming a third capacitor protective film of aluminum oxide over the first insulating film, the third capacitor protective film covering the first wiring;   forming a fourth insulating film of silicon oxide having a thickness equal to or thicker than 300 nm over the third capacitor protective film by plasma enhanced chemical vapor deposition using tetraethoxysilane-containing gas as source gas; and   forming a third insulating film of silicon oxide over the fourth insulating film by chemical vapor deposition using high density plasma.   
     
     
         5 . The manufacture method for a semiconductor device according to  claim 1 , further comprising:
 forming a first wiring of conductive material over the first insulating film;   forming a third capacitor protective film of aluminum oxide having a thickness equal to or thicker than 30 nm over the first insulating film, the third capacitor protective film covering the first wiring; and   forming a third insulating film of silicon oxide over the third capacitor protective film by chemical vapor deposition using high density plasma.   
     
     
         6 . The manufacture method for a semiconductor device according to  claim 1 , further comprising:
 forming a first wiring of conductive material over the first insulating film;   forming a third insulating film of silicon oxide over the first insulating film, the third insulating film covering the first wiring;   planarizing a surface of the third insulating film;   forming a fourth capacitor protective film of aluminum oxide having a thickness equal to or thicker than 30 nm over the planarized third insulating film;   forming a second wiring of conductive material over the fourth capacitor protective film; and   forming a fifth insulating film of silicon oxide over the fourth capacitor protective film by chemical vapor deposition using high density plasma, the fifth insulating film covering the second wiring.   
     
     
         7 . The manufacture method for a semiconductor device according to  claim 1 , further comprising:
 forming a first wiring of conductive material over the first insulating film;   forming a third insulating film of silicon oxide over the first insulating film, the third insulating film covering the first wiring;   planarizing a surface of the third insulating film;   forming a fourth capacitor protective film of aluminum oxide over the planarized third insulating film;   forming a sixth insulating film of silicon oxide having a thickness equal to or thicker than 300 nm over the fourth capacitor protective film by plasma enhanced chemical vapor deposition using tetraethoxysilane-containing gas as source gas;   forming a second wiring of conductive material over the sixth insulating film; and   forming a fifth insulating film of silicon oxide over the sixth insulating film by chemical vapor deposition using high density plasma, the fifth insulating film covering the second wiring.   
     
     
         8 . The manufacture method for a semiconductor device according to  claim 1 , wherein the first capacitor protective film is formed by chemical vapor deposition. 
     
     
         9 . The manufacture method for a semiconductor device according to  claim 8 , wherein the first capacitor protective film is formed by atomic layer deposition for alternately supplying ozone and trimethylaluminum. 
     
     
         10 . A manufacture method for a semiconductor device comprising:
 forming a ferroelectric capacitor over a semiconductor substrate, the ferroelectric capacitor comprising a lower electrode, a ferroelectric film and an upper electrode stacked in an order recited;   forming a first capacitor protective film of aluminum oxide, the first capacitor protective film covering the ferroelectric capacitor;   forming a seventh insulating film of silicon oxide having a thickness equal to or thicker than 300 nm over the first capacitor protective film by plasma enhanced chemical vapor deposition using tetraethoxysilane-containing gas as source gas; and   forming a first insulating film of silicon oxide over the seventh insulating film by chemical vapor deposition using high density plasma.   
     
     
         11 . The manufacture method for a semiconductor device according to  claim 10 , further comprising:
 planarizing a surface of the first insulating film;   forming a second capacitor protective film of aluminum oxide over the planarized first insulating film;   forming a second insulating film of silicon oxide having a thickness equal to or thicker than 300 nm over the second capacitor protective film by plasma enhanced chemical vapor deposition using tetraethoxysilane-containing gas as source gas;   forming a first wiring of conductive material over the second insulating film; and   forming a third insulating film of silicon oxide over the second insulating film by chemical vapor deposition using high density plasma, the third insulating film covering the first wiring.   
     
     
         12 . The manufacture method for a semiconductor device according to  claim 10 , further comprising:
 planarizing a surface of the first insulating film;   forming a second capacitor protective film of aluminum oxide having a thickness equal to or thicker than 30 nm over the planarized first insulating film;   forming a first wiring of conductive material over the second insulating film; and   forming a third insulating film of silicon oxide over the second capacitor protective film by chemical vapor deposition using high density plasma, the third insulating film covering the first wiring.   
     
     
         13 . The manufacture method for a semiconductor device according to  claim 10 , further comprising:
 forming a first wiring of conductive material over the first insulating film;   forming a third capacitor protective film of aluminum oxide over the first insulating film, the third capacitor protective film covering the first wiring;   forming a fourth insulating film of silicon oxide having a thickness equal to or thicker than 300 nm over the third capacitor protective film by plasma enhanced chemical vapor deposition using tetraethoxysilane-containing gas as source gas; and   forming a third insulating film of silicon oxide over the fourth insulating film by chemical vapor deposition using high density plasma.   
     
     
         14 . The manufacture method for a semiconductor device according to  claim 10 , further comprising:
 forming a first wiring of conductive material over the first insulating film;   forming a third capacitor protective film of aluminum oxide having a thickness equal to or thicker than 30 nm over the first insulating film, the third capacitor protective film covering the first wiring; and   forming a third insulating film of silicon oxide over the third capacitor protective film by chemical vapor deposition using high density plasma.   
     
     
         15 . The manufacture method for a semiconductor device according to  claim 10 , further comprising:
 forming a first wiring of conductive material over the first insulating film;   forming a third insulating film of silicon oxide over the first insulating film, the third insulating film covering the first wiring;   planarizing a surface of the third insulating film;   forming a fourth capacitor protective film of aluminum oxide having a thickness equal to or thicker than 30 nm over the planarized third insulating film;   forming a second wiring of conductive material over the fourth capacitor protective film; and   forming a fifth insulating film of silicon oxide over the fourth capacitor protective film by chemical vapor deposition using high density plasma, the fifth insulating film covering the second wiring.   
     
     
         16 . The manufacture method for a semiconductor device according to  claim 10 , further comprising:
 forming a first wiring of conductive material over the first insulating film;   forming a third insulating film of silicon oxide, the third insulating film covering the first wiring;   planarizing a surface of the third insulating film;   forming a fourth capacitor protective film of aluminum oxide over the planarized third insulating film;   forming a sixth insulating film of silicon oxide having a thickness equal to or thicker than 300 nm over the fourth capacitor protective film by plasma enhanced chemical vapor deposition using tetraethoxysilane-containing gas as source gas;   forming a second wiring of conductive material over the sixth insulating film; and   forming a fifth insulating film of silicon oxide over the sixth insulating film by chemical vapor deposition using high density plasma, the fifth insulating film covering the second wiring.   
     
     
         17 . The manufacture method for a semiconductor device according to  claim 10 , wherein the first capacitor protective film is formed by chemical vapor deposition. 
     
     
         18 . The manufacture method for a semiconductor device according to  claim 17 , wherein the first capacitor protective film is formed by atomic layer deposition for alternately supplying ozone and trimethylaluminum. 
     
     
         19 . A manufacture method for a semiconductor device comprising:
 forming a ferroelectric capacitor over a semiconductor substrate, the ferroelectric capacitor comprising a lower electrode, a ferroelectric film and an upper electrode stacked in an order recited;   forming a first capacitor protective film of aluminum oxide, the first capacitor protective film covering the ferroelectric capacitor; and   forming a first insulating film of silicon oxide over the first capacitor protective film by chemical vapor deposition using high density plasma,   wherein a thickness of the first capacitor protective film is equal to or thicker than a lower limit thickness, the lower limit thickness being defined through a process comprising:   preparing samples, each of the samples comprising a substrate, a Ti film on the substrate, an aluminum oxide film on the Ti film, and a silicon oxide film on the aluminum oxide film, the aluminum oxide film being formed in a same way as the first capacitor protective film, the silicon oxide film being formed in a same way as the first insulating film, thicknesses of the aluminum oxide films of the samples being different from one another;   performing thermal desorption spectroscopy for the samples to obtain hydrogen desorption spectrums;   extracting some samples as first samples from the samples, each of the first samples having no peak of the hydrogen desorption spectrum in a temperature range equal to or lower than 700° C. and having a peak of the hydrogen desorption spectrum in a temperature range higher than 700° C.; and   adopting, as the lower limit thickness, a thickness of the aluminum oxide film of one sample whose aluminum oxide film is thinnest among the aluminum oxide films of the first samples.   
     
     
         20 . A manufacture method for a semiconductor device comprising:
 forming a ferroelectric capacitor over a semiconductor substrate, the ferroelectric capacitor comprising a lower electrode, a ferroelectric film and an upper electrode stacked in an order recited;   forming a first capacitor protective film of aluminum oxide, the first capacitor protective film covering the ferroelectric capacitor;   forming a seventh insulating film of silicon oxide over the first capacitor protective film by plasma enhanced chemical vapor deposition using tetraethoxysilane-containing gas as source gas; and   forming a first insulating film of silicon oxide over the seventh insulating film by chemical vapor deposition using high density plasma,   wherein a thickness of the seventh insulating film is equal to or thicker than a lower limit thickness, the lower limit thickness being defined through a process comprising:   preparing samples, each of the samples comprising a substrate, a Ti film on the substrate, an aluminum oxide film having a thickness of 20 nm on the Ti film, a first silicon oxide film on the aluminum oxide film, and a second silicon oxide film on the first silicon oxide film, the aluminum oxide film being formed in a same way as the first capacitor protective film, the first silicon oxide film being formed in a same way as the seventh insulating film, the second silicon oxide film being formed in a same way as the first insulating film, thicknesses of the first silicon oxide films of the samples being different from one another;   performing thermal desorption spectroscopy for the samples to obtain hydrogen desorption spectrums;   extracting some samples as first samples from the samples, each of the first samples having no peak of the hydrogen desorption spectrum in a temperature range equal to or lower than 700° C. and having a peak of the hydrogen desorption spectrum in a temperature range higher than 700° C.; and   adopting, as the lower limit thickness, a thickness of the first silicon oxide film of one sample whose first silicon oxide film is thinnest among the first silicon oxide films of the first samples.