Process for fabricating a semiconductor memory device including a capacitor having a cylindrical storage node electrode
First Claim
1. A process for fabricating a semiconductor device having a capacitor, said process comprising the steps of:
- providing a semiconductor substrate having a transistor formed therein;
forming an interlayer insulating film over a surface of the semiconductor substrate;
forming in sequence an impurity-doped first polysilicon film and a first insulating film on a surface of said interlayer insulating film;
selectively removing said first insulating film and said impurity-doped first polysilicon film to define a core made of said first insulating film and a bottom electrode made of said impurity-doped first polysilicon film;
forming in sequence an impurity-undoped second polysilicon film and a second insulating film over said core and said bottom electrode;
selectively removing said second insulating film until a portion of said impurity-undoped second polysilicon film covering a top surface of said core is exposed to thereby form a part of said second insulating film, wherein said part of said second insulating film serves as a cylindrical spacer which surrounds a sidewall of said core and a sidewall of said bottom electrode and wherein said impurity-undoped second polysilicon film is disposed between the sidewall of said core and said cylindrical spacer;
selectively doping an impurity into said impurity-undoped second polysilicon film by using said cylindrical spacer as a mask to thereby divide said impurity-undoped second polysilicon film into an impurity-doped portion covering the top surface of said core and an impurity-undoped portion disposed between the sidewall of said core and said cylindrical spacer;
selectively removing said impurity-doped portion by using said cylindrical spacer as a mask to thereby leave said impurity-undoped portion as an impurity-undoped-polysilicon-film spacer disposed between the sidewall of said core and said cylindrical spacer;
removing said cylindrical spacer and said core while leaving said bottom electrode and said impurity-undoped-polysilicon-film spacer; and
introducing an impurity into said impurity-undoped-polysilicon-film spacer to form a cylindrical electrode and to form a storage node electrode comprising said cylindrical electrode and said bottom electrode, wherein said storage node electrode serves as one electrode of said capacitor.
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Accused Products
Abstract
A process for fabricating a semiconductor device having a capacitor is disclosed. The process comprises the steps of: providing a semiconductor substrate having a transistor formed therein; forming an interlayer insulating film over a surface of the semiconductor substrate; forming in sequence a first polysilicon film and a first insulating film on a surface of the interlayer insulating film; selectively removing the first insulating film and the first polysilicon film to define a core made of the first insulating film and a bottom electrode made of the first polysilicon film; forming in sequence an undoped second polysilicon film and a second insulating film over the core and the bottom electrode; selectively removing the second insulating film to leave a part of the second insulating film, the part of the second insulating film serving as a cylindrical spacer which surrounds sidewalls of the core and the bottom electrode with intervention of the second polysilicon film; selectively removing a portion the second polysilicon film using the cylindrical spacer as a mask to form an undoped-polysilicon-film spacer interposed between the core and the cylindrical spacer; removing the cylindrical spacer and the core with leaving the bottom electrode and the undoped-polysilicon-film spacer; and introducing an impurity into the undoped-polysilicon-film spacer to form a cylindrical electrode, and to form a storage node electrode comprising the cylindrical electrode and the bottom electrode, the storage node electrode serves as one electrode of the capacitor.
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Citations
12 Claims
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1. A process for fabricating a semiconductor device having a capacitor, said process comprising the steps of:
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providing a semiconductor substrate having a transistor formed therein; forming an interlayer insulating film over a surface of the semiconductor substrate; forming in sequence an impurity-doped first polysilicon film and a first insulating film on a surface of said interlayer insulating film; selectively removing said first insulating film and said impurity-doped first polysilicon film to define a core made of said first insulating film and a bottom electrode made of said impurity-doped first polysilicon film; forming in sequence an impurity-undoped second polysilicon film and a second insulating film over said core and said bottom electrode; selectively removing said second insulating film until a portion of said impurity-undoped second polysilicon film covering a top surface of said core is exposed to thereby form a part of said second insulating film, wherein said part of said second insulating film serves as a cylindrical spacer which surrounds a sidewall of said core and a sidewall of said bottom electrode and wherein said impurity-undoped second polysilicon film is disposed between the sidewall of said core and said cylindrical spacer; selectively doping an impurity into said impurity-undoped second polysilicon film by using said cylindrical spacer as a mask to thereby divide said impurity-undoped second polysilicon film into an impurity-doped portion covering the top surface of said core and an impurity-undoped portion disposed between the sidewall of said core and said cylindrical spacer; selectively removing said impurity-doped portion by using said cylindrical spacer as a mask to thereby leave said impurity-undoped portion as an impurity-undoped-polysilicon-film spacer disposed between the sidewall of said core and said cylindrical spacer; removing said cylindrical spacer and said core while leaving said bottom electrode and said impurity-undoped-polysilicon-film spacer; and introducing an impurity into said impurity-undoped-polysilicon-film spacer to form a cylindrical electrode and to form a storage node electrode comprising said cylindrical electrode and said bottom electrode, wherein said storage node electrode serves as one electrode of said capacitor. - View Dependent Claims (2, 3, 4)
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5. A process for fabricating a semiconductor device having a capacitor, said process comprising the steps of:
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providing a semiconductor substrate having a transistor formed therein; forming an interlayer insulating film over a surface of the semiconductor substrate; forming in sequence an impurity-doped first polysilicon film and a first insulating film on a surface of said interlayer insulating film; selectively removing said first insulating film to define a core made of said first insulating film; forming in sequence an impurity-undoped second polysilicon film and second insulating film over said core; selectively removing said second insulating film until a portion of said impurity-undoped second polysilicon film covering a top surface of said core is exposed to thereby form a part of said second insulating film, wherein said part of said second insulating film serves as a cylindrical spacer which surrounds a sidewall of said core and wherein said impurity-undoped second polysilicon film is disposed between the sidewall of said core and said cylindrical spacer; selectively doping an impurity into said impurity-undoped second polysilicon film by using said cylindrical spacer as a mask to thereby divide said impurity-undoped second polysilicon film into a first impurity-doped portion covering the top surface of said core, an impurity-undoped portion disposed between the sidewall of said core and said cylindrical spacer, and a second impurity-doped portion formed on a corresponding portion of said impurity-doped first polysilicon film; selectively removing said first and second impurity-doped portions and said corresponding portion of said impurity-doped first polysilicon film by using said cylindrical spacer as a mask to thereby leave said impurity-undoped portion as an impurity-undoped-polysilicon-film spacer wherein said impurity-undoped-polysilicon-film spacer is disposed between the sidewall of said core, said cylindrical spacer, and a bottom electrode of said impurity-doped first polysilicon film; removing said cylindrical spacer and said core while leaving said impurity-undoped-polysilicon-film spacer; and introducing an impurity into said impurity-undoped-polysilicon-film spacer to form a cylindrical electrode and to form a storage node electrode comprising said cylindrical electrode and said bottom electrode, wherein said storage node electrode serves as one electrode of said capacitor. - View Dependent Claims (6, 7, 8)
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9. A process for fabricating a semiconductor device having a capacitor, said process comprising the steps of:
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providing a semiconductor substrate having a transistor formed therein; forming an interlayer insulating film over a surface of the semiconductor substrate; forming in sequence a first polysilicon film and a first insulating film on a surface of said interlayer insulating film; selectively removing said first insulating film to define a core made of said first insulating film; selectively removing said first polysilicon film to define a bottom electrode made of said first polysilicon film; forming in sequence an undoped second polysilicon film and a second insulating film over said core; selectively removing said second insulating film until a portion of said undoped second polysilicon film covering a top surface of said core is exposed to thereby form a part of said second insulating film, wherein said part of said second insulating film serves as a cylindrical spacer which surrounds a sidewall of said core and wherein said second polysilicon film is disposed between the sidewall of said core and said cylindrical spacer; selectively doping an impurity into said undoped second polysilicon film by using said cylindrical spacer as a mask to thereby divide said undoped polysilicon film into an impurity-doped portion covering the top surface of said core and an impurity-undoped portion disposed between the sidewall of said core and said cylindrical spacer; selectively removing said impurity-doped portion by using said cylindrical spacer as a mask to thereby leave said impurity-undoped portion as an undoped-polysilicon-film spacer disposed between the sidewall of said core and said cylindrical spacer; removing said cylindrical spacer and said core while leaving said bottom electrode and said undoped-polysilicon-film spacer; and introducing an impurity into said undoped-polysilicon-film spacer to form a cylindrical electrode and to form a storage node electrode comprising said cylindrical electrode and said bottom electrode, wherein said storage node electrode serves as one electrode of said capacitor. - View Dependent Claims (10, 11, 12)
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Specification