Method of manufacturing semiconductor device having tungsten gates electrode

1. A method of manufacturing a semiconductor device having tungsten gate electrodes, comprising;

(a) forming a gate oxide film on a semiconductor substrate, a polysilicon film above the gate oxide film, and a nitride film above the polysilicon film, and then patterning the nitride film, the polysilicon film, and the gate oxide film to form a plurality of poly gates;

(b) forming a spacer at a side of at least one of the poly gates;

(c) forming a sacrificial nitride film on the entire resulting surface including the poly gates and the spacer, and then forming an interlayer insulation film on the entire resulting surface including the sacrificial nitride film;

(d) removing a portion of the interlayer insulation film to expose a portion of the sacrificial nitride film formed on the poly gates, and then polishing the sacrificial nitride film formed on the poly gates to expose the nitride film;

(e) removing a top portion of the sacrificial nitride film while removing the nitride film;

(f) forming an insulation film spacer at the side exposed through removal of the nitride film, and filling a portion from which the sacrificial nitride film is removed with an insulation film; and

(g) forming tungsten gates in portions from which the nitride films are removed.

2. The method of claim 1 , wherein (a) further comprises:

forming a hard mask film on the nitride film;

patterning the hard mask film;

etching the nitride film, the polysilicon film, and the gate oxide film using the patterned hard mask film as a mask, thereby forming the plurality of poly gates; and

removing the hard mask film.

3. The method of claim 2 , wherein the hard mask film is an alpha carbon film.

4. The method of claim 2 , comprising forming the hard mask film to a thickness of 500 Å to 2000 Å.

5. The method of claim 2 , comprising removing the hard mask film using oxygen plasma.

6. The method of claim 1 , comprising forming the nitride film to a thickness of 500 Å to 2000 Å.

7. The method of claim 1 , wherein (d) comprises the steps of:

polishing the interlayer insulation film by chemical mechanical polishing to expose the sacrificial nitride film; and

performing an additional chemical mechanical polishing process to completely remove the sacrificial nitride film formed on the poly gates.

8. The method of claim 7 , wherein the additional chemical mechanical polishing process comprises removing the nitride film below the sacrificial nitride film up to a thickness of 200 Å to 500 Å.

9. The method of claim 1 , wherein (e) further comprises removing the nitride film and the sacrificial nitride film with a phosphoric acid solution.

10. The method of claim 1 , wherein (f) further comprises:

depositing an insulation film on the entire surface to fill a portion from which the sacrificial nitride film is removed with the insulation film; and

etching back the insulation film to form the insulation film spacer at the side exposed through removal of the nitride film.

11. The method of claim 10 , comprising forming the insulation film to a thickness of 50 Å to 300 Å.

12. The method of claim 10 , wherein the insulation film is selected from the group consisting of nitride films and oxide films.

13. The method of claim 1 , wherein (g) further comprises removing the interlayer insulation film and the sacrificial nitride film of the contact region to form a contact hole and then forming the tungsten gates in portions from which the nitride films have been removed, wherein the contact hole is buried with tungsten to form a contact.