Semiconductor device and fabrication process thereof, method of forming a device isolation structure
AssigneeFujitsu Limited of Kawasaki, Japan
InventorMasanobu Hatanaka
Life of this patent
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Abstract
In a semiconductor device having an STI structure, a space is formed by causing a recession in an oxide film on a surface of a substrate with regard to a sidewall surface of a device isolation trench at an edge of the device isolation trench, and a Si film is formed so as to fill the trench. Further, the oxide film is removed from the surface of the substrate while leaving the Si film, and the trench is filled with an oxide film. Further, the Si film is oxidized to form an oxide film forming a part of the oxide film.
Claims9
A semiconductor device, comprising:
- a substrate;
- and
- a device isolation structure formed on said substrate for defining a device region,
- said device isolation structure comprising:
- a trench formed in said substrate;
- and
- an insulating film filling said trench,
- said insulating film including an extension part extending outwardly from an outer edge of said trench on a surface of said substrate, and a projecting part projecting upwardly from said extension part in correspondence to said outer edge of said trench.
A method of fabricating a semiconductor device having a shallow trench device isolation structure, comprising the steps of:
- forming a first oxide film on a Si substrate;
- forming a polishing stopper layer on said first oxide film;
- forming a trench through said polishing stopper layer and further through said first oxide film such that said trench reaches said Si substrate;
- etching said first oxide film exposed at said trench to as to cause a recession in a sidewall surface of said first oxide film with respect to a sidewall surface of said trench, such that there is formed a space between a top surface of said Si substrate and a bottom surface of said polishing stopper layer such that said space is opened at said sidewall of said trench;
- oxidizing said sidewall surface and a bottom surface of said trench to form a second oxide film such that said second oxide film covers said top surface of said Si substrate exposed by said space in continuation with said first oxide film;
- depositing a Si film on said polishing stopper layer such that said Si film covers said second oxide film and such that said Si film fills said space;
- depositing a third oxide film on said Si film so as to fill said trench;
- removing said third oxide film and said Si film underlying said third oxide film by a chemical mechanical polishing process while using said polishing stopper layer as a stopper;
- removing said polishing stopper layer and said first oxide film from said top surface of said Si substrate;
- and
- oxidizing said Si film.
A method of fabricating a semiconductor device having a shallow trench device isolation structure, comprising the steps of:
- forming a first oxide film on a Si substrate;
- forming a polishing stopper layer on said first oxide film;
- forming a trench through said polishing stopper layer and further through said first oxide film underneath said polishing stopper layer such that said trench reaches said Si substrate;
- etching said first oxide film exposed at said trench so as to cause a recession of a sidewall surface of said first oxide film with respect to a sidewall surface of said trench, such that there is formed a space between a top surface of said Si substrate and a bottom surface of said polishing stopper such that said space is opened at said sidewall surface of said trench;
- oxidizing said sidewall surface and a bottom surface of said trench to form a second oxide film such that said second oxide film covers said sidewall surface and said bottom surface of said trench and said top surface of said Si substrate exposed by said space in continuation with said first oxide surface;
- forming a Si film in said trench such that said Si film fills said space;
- depositing a third oxide film so as to fill said trench;
- removing said third oxide film by a chemical mechanical polishing process while using said polishing layer as a stopper;
- removing said polishing stopper layer and said first oxide film from said top surface of said Si substrate;
- and
- oxidizing said Si film.
A method of fabricating a semiconductor device comprising a device isolation trench formed in a substrate and an insulating film filling said device isolation trench, comprising the steps of:
- causing a recession in an oxide film formed on a surface of said substrate with regard to a sidewall surface of said device isolation trench at an edge of said device isolation trench, to form a space;
- forming a Si film so as to fill said space;
- removing said oxide film from said surface of said substrate while leaving said Si film;
- filling said trench by an oxide film;
- and
- oxidizing said Si film to form an oxide film as a part of said oxide film.
A method of forming a device isolation structure comprising a device isolation trench formed in a substrate and an insulating film filling said device isolation trench, said method comprising the steps of:
- causing a recession in an oxide film formed on a surface of said substrate with respect to a sidewall surface of said device isolation trench at an edge of said device isolation trench, to form a space;
- forming a Si film so as to fill said space;
- removing said oxide film from said top surface of said substrate while leaving said Si film;
- filling said trench by an oxide film;
- and
- oxidizing said Si film to form an oxide film as a part of said oxide film.
Dependencies are inferred from the claim text.