Semiconductor device and method of manufacturing the same

Abstract

A lower electrode film, a ferroelectric film, and an upper electrode film are formed on an insulation film covering a transistor formed on a semiconductor substrate. Furthermore, a Pt film is formed as a cap layer on the upper electrode film. Then, a hard mask (a TiN film and an SiO 2 film) of a predetermined pattern is formed on the Pt film, and the Pt film and the upper electrode film are etched. Then, an insulating protective film is formed on an entire surface, and a side surface of the upper electrode film is covered with the insulating protective film. Next, the ferroelectric film and the lower electrode film are etched, thus forming a ferroelectric capacitor.

1 . A method of manufacturing a semiconductor device comprising:
 forming an insulation film on a semiconductor substrate;   forming a lower electrode film on the insulation film;   forming a ferroelectric film on the lower electrode film;   forming an upper electrode film on the ferroelectric film;   forming a hard mask of a predetermined pattern on the upper electrode film;   removing the upper electrode film on a portion uncovered with the hard mask;   forming an insulating protective film on an entire upper surface of the semiconductor substrate and covering a side surface of the remaining upper electrode film with the insulating protective film;   removing the ferroelectric film and the lower electrode film on the portion uncovered with the hard mask; and   removing the hard mask.   
     
     
         2 . The method of manufacturing a semiconductor device according to  claim 1 , wherein, in the removing of the upper electrode film, the ferroelectric film is etched halfway in a thickness direction. 
     
     
         3 . The method of manufacturing a semiconductor device according to  claim 1 , wherein the insulating protective film is made to be 5 to 20 nm thick. 
     
     
         4 . The method of manufacturing a semiconductor device according to  claim 1 , wherein temperature in film formation of the insulating protective film is less than 300° C. 
     
     
         5 . The method of manufacturing a semiconductor device according to  claim 1 , wherein the insulating protective film is formed by a CVD method or an ALD method. 
     
     
         6 . The method of manufacturing a semiconductor device according to  claim 1 , wherein the insulating protective film is composed of at least one kind of insulation film selected from a group consisting of an SiN film, an Al 2 O 3  film, a Ta 2 O 5  film, and an SiC film. 
     
     
         7 . A method of manufacturing a semiconductor device comprising:
 forming an insulation film on a semiconductor substrate;   forming a lower electrode film on the insulation film;   forming a ferroelectric film on the lower electrode film;   forming an upper electrode film on the ferroelectric film;   forming a hard mask of a predetermined pattern on the upper electrode film;   removing the upper electrode film on a portion uncovered with the hard mask;   forming a first insulating protective film on an entire upper surface of the semiconductor substrate and covering a side surface of the remaining upper electrode film with the first insulating protective film;   removing the ferroelectric film on the portion uncovered with the hard mask;   forming a second insulating protective film on the entire upper surface of the semiconductor substrate and covering a side surface of the remaining ferroelectric film with the second insulating protective film;   removing the lower electrode film on the portion uncovered with the hard mask; and   removing the hard mask.   
     
     
         8 . The method of manufacturing a semiconductor device according to  claim 7 , wherein, in the removing of the upper electrode film, the ferroelectric film is etched halfway in a thickness direction. 
     
     
         9 . The method of manufacturing a semiconductor device according to  claim 7 , wherein the first insulating protective film and the second insulating protective film are each made to be 5 to 20 nm thick. 
     
     
         10 . The method of manufacturing a semiconductor device according to  claim 7 , wherein temperature in film formation of the first insulating protective film and the second insulating protective film is less than 300° C. 
     
     
         11 . The method of manufacturing a semiconductor device according to  claim 7 , wherein the first insulating protective film and the second insulating protective film are formed by a CVD method or an ALD method. 
     
     
         12 . The method of manufacturing a semiconductor device according to  claim 7 , wherein the first insulating protective film and the second insulating protective film are each composed of at least one kind of insulation film selected from the group consisting of an SiN film, an Al 2 O 3  film, a Ta 2 O 5  film, and an SiC film. 
     
     
         13 . A method of manufacturing a semiconductor device comprising:
 forming an insulation film on a semiconductor substrate;   forming a lower electrode film on the insulation film;   forming a ferroelectric film on the lower electrode film;   forming an upper electrode film on the ferroelectric film;   forming a hard mask of a predetermined pattern on the upper electrode film;   removing the upper electrode film and the ferroelectric film on a portion uncovered with the hard mask;   forming an insulating protective film on an entire upper surface of the semiconductor substrate and covering side surfaces of the remaining upper electrode film and the remaining ferroelectric film with the insulating protective film;   removing the lower electrode film on the portion uncovered with the hard mask; and   removing the hard mask.   
     
     
         14 . The method of manufacturing a semiconductor device according to  claim 13 , wherein the insulating protective film is made to be 5 to 20 nm thick. 
     
     
         15 . The method of manufacturing a semiconductor device according to  claim 13 , wherein temperature in film formation of the insulating protective film is less than 300° C. 
     
     
         16 . The method of manufacturing a semiconductor device according to  claim 13 , wherein the insulating protective film is formed by a CVD method or an ALD method. 
     
     
         17 . The method of manufacturing a semiconductor device according to  claim 13 , wherein the insulating protective film is composed of at least one kind of insulation film selected from the group consisting of an SiN film, an Al 2 O 3  film, a Ta 2 O 5  film, and an SiC film. 
     
     
         18 . A semiconductor device comprising:
 a semiconductor substrate;   a transistor formed on the semiconductor substrate;   an interlayer insulation film formed on the semiconductor substrate and covering the transistor;   a ferroelectric capacitor constructed by stacking a lower electrode film, a ferroelectric film, and an upper electrode film, and arranged on the interlayer insulation film, the lower electrode film being electrically connected to the transistor; and   an insulating protective film being 5 to 20 nm thick, and covering at least a side surface of the upper electrode film.   
     
     
         19 . The semiconductor device according to  claim 18 , wherein the insulating protective film is composed of at least one kind of insulation film selected from the group consisting of an SiN film, an Al 2 O 3  film, a Ta 2 O 5  film, and an SiC film. 
     
     
         20 . The semiconductor device according to  claim 18 , further comprising a capacitor protective film which covers the ferroelectric capacitor and prevents entry of hydrogen and moisture into the ferroelectric film. 
     
     
         21 . The semiconductor device according to  claim 18 , wherein the ferroelectric film is formed of at least one kind of ferroelectric material selected from the group consisting of PZT, PLZT, BTL, STB and SBTN. 
     
     
         22 . A semiconductor device comprising:
 a semiconductor substrate;   a transistor formed on the semiconductor substrate;   an interlayer insulation film formed on the semiconductor substrate and covering the transistor;   a ferroelectric capacitor constructed by stacking a lower electrode film, a ferroelectric film, and an upper electrode film, and arranged on the interlayer insulation film, the lower electrode film being electrically connected to the transistor;   a first insulating protective film covering an entire side surface of the upper electrode film and partly covering a side surface of the ferroelectric film; and   a second insulating protective film covering the ferroelectric capacitor and the first insulating protective film.   
     
     
         23 . A semiconductor device comprising:
 a semiconductor substrate;   a transistor formed on the semiconductor substrate;   an interlayer insulation film formed on the semiconductor substrate and covering the transistor;   a ferroelectric capacitor constructed by stacking a lower electrode film, a ferroelectric film, and an upper electrode film, and arranged on the interlayer insulation film, the lower electrode film being electrically connected to the transistor;   a first insulating protective film covering an entire side surface of the upper electrode film and partly covering a side surface of the ferroelectric film;   a second insulating protective film formed to overlap the first insulating protective film and covering the entire side surface of the upper electrode film an entire side surface of the ferroelectric film; and   a third insulating protective film formed to overlap the second insulating protective film, and covering the entire side surface of the upper electrode film, the entire side surface of the ferroelectric film, and an entire side surface of the lower electrode film.   
     
     
         24 . A semiconductor device comprising:
 a semiconductor substrate;   a transistor formed on the semiconductor substrate;   an interlayer insulation film formed on the semiconductor substrate and covering the transistor;   a ferroelectric capacitor constructed by stacking a lower electrode film, a ferroelectric film, and an upper electrode film, and arranged on the interlayer insulation film, the lower electrode film being electrically connected to the transistor;   a first insulating protective film covering an entire side surface of the upper electrode film and an entire side surface of the ferroelectric film;   a second insulating protective film formed to overlap the first insulating protective film, and covering the entire side surface of the upper electrode film and the entire side surface of the ferroelectric film; and   a second insulating protective film covering the ferroelectric capacitor and the first insulating protective film.