Granted Patent B2

US 8,043,903 · App. 12/895,988 · Granted Oct 25, 2011

Abstract

Claims (52)

1. A method of manufacturing a semiconductor device, comprising:

forming a first recess in a semiconductor substrate to define an active region on the semiconductor substrate, the active region including a protruding portion of the semiconductor substrate surrounded by the first recess, and the protruding portion having a sloped side surface;

forming a first insulating film that fills the first recess;

forming a gate recess in the active region to form a thin film portion that upwardly extends, the thin film portion being positioned between the gate recess and the first insulating film, the thin film portion being a part of the protruding portion; and

removing an upper part of the thin film portion by wet-etching to adjust a height of the thin film portion,

wherein the upper part of the thin film portion is removed by using pure water as a solution for the wet-etching.

2. The method according to claim 1 , wherein forming the gate recess comprises removing a part of the protruding portion in the active region by dry-etching.

3. The method according to claim 1 , wherein a temperature of the pure water is set in the range of 60° C. to 80° C.

4. The method according to claim 1 , wherein the height of the thin film portion is adjusted in the range of 30 nm to 50 nm by the wet-etching.

5. The method according to claim 1 , wherein forming the first recess comprises changing an angle between the sloped side surface of the protruding portion and a plane perpendicular to an upper surface of the semiconductor substrate in order to enlarge a horizontal thickness of the thin film portion.

6. The method according to claim 1 , further comprising:

after removing the upper part of the thin film portion, forming a second insulating film covering an inner surface of the gate recess and an upper surface of the active region; and

forming a gate electrode on the second insulating film, the gate electrode filling the gate recess and covering a part of the active region.

7. The method according to claim 6 , further comprising:

after forming the gate electrode, introducing an impurity into the active region through the second insulating film to form source/drain regions;

forming a third insulating film over the gate electrode and the active region; and

forming contact plugs penetrating the second insulating film, each of the contact plugs being electrically connected to each of the source/drain regions.

8. A method of manufacturing a semiconductor device, comprising:

forming a first recess in a semiconductor substrate to define an active region on the semiconductor substrate, the active region including a protruding portion of the semiconductor substrate surrounded by the first recess, and the protruding portion having a sloped side surface;

forming a first insulating film that fills the first recess;

forming a gate recess in the active region to form a thin film portion that upwardly extends, the thin film portion being positioned between the gate recess and the first insulating film, the thin film portion being a part of the protruding portion; and

removing an upper part of the thin film portion by wet-etching to adjust a height of the thin film portion,

wherein the upper part of the thin film portion is removed by using phosphoric acid solution as a wet-etching solution.

9. The method according to claim 8 , wherein a temperature of the phosphoric acid solution is set in the range of 150° C. to 170° C.

10. A method of manufacturing a semiconductor device, comprising:

forming a first recess in a semiconductor substrate to define an active region on the semiconductor substrate, the active region including a first protruding portion of the semiconductor substrate surrounded by the first recess;

forming a mask insulating film on a side surface of the first protruding portion;

forming a second recess under the first recess using the mask insulating film as a part of a dry-etching mask to form a second protruding portion under the first protruding portion, the second protruding portion having a sloped side surface, and the active region including the second protruding portion of the semiconductor substrate surrounded by the second recess;

forming a first insulating film filling the first and second recesses;

forming a gate recess in the active region to form a thin film portion that upwardly extends, the thin film portion being positioned between the gate recess and the first insulating film, the thin film portion being a part of the second protruding portion, and a bottom surface of the gate recess reaching to the second protruding portion; and

removing an upper part of the thin film portion by wet-etching to adjust a height of the thin film portion,

wherein the upper part of the thin film portion is removed by using pure water as a solution for the wet-etching.

11. The method according to claim 10 , wherein

the side surface of the first protruding portion is substantially perpendicular to an upper surface of the semiconductor substrate, and

the second protruding portion is larger in horizontal thickness than the first protruding portion.

12. The method according to claim 11 , wherein forming the second recess comprises changing an angle between a side surface of the second protruding portion and a plane perpendicular to the upper surface of the semiconductor substrate in order to enlarge a horizontal thickness of the thin film portion.

13. The method according to claim 10 , wherein a temperature of the pure water is set in the range of 60° C. to 80° C.

14. The method according to claim 10 , wherein the height of the thin film portion is adjusted in the range of 30 nm to 50 nm by the wet-etching.

15. A method of manufacturing a semiconductor device, comprising:

forming a recess in a semiconductor substrate to form a thin film portion, the semiconductor substrate having a sloped side surface, the thin film portion being a part of the semiconductor substrate, and the thin film portion upwardly extending along a side surface of the recess; and

removing an upper part of the thin film portion by wet-etching to adjust a height of the thin film portion,

wherein the upper part of the thin film portion is removed by using pure water as a solution for the wet-etching.

16. The method according to claim 15 , wherein a temperature of the pure water is set in the range of 60° C. to 80° C.

17. The method according to claim 15 , wherein the height of the thin film portion is adjusted in the range of 30 nm to 50 nm by the wet-etching.

18. A method of manufacturing a semiconductor device, comprising:

forming a recess in a semiconductor substrate to form a thin film portion, the semiconductor substrate having a sloped side surface, the thin film portion being a part of the semiconductor substrate, and the thin film portion upwardly extending along a side surface of the recess; and

removing an upper part of the thin film portion by wet-etching to adjust a height of the thin film portion,

wherein the upper part of the thin film portion is removed by using pure phosphoric acid solution as a solution for the wet-etching.

19. The method according to claim 18 , wherein a temperature of the phosphoric acid solution is set in the range of 150° C. to 170° C.

20. A method of manufacturing a semiconductor substrate, comprising:

forming a recess in a semiconductor substrate to form a thin film portion, the thin film portion extending upwardly along a side surface of the recess; and

removing an upper part of the thin film portion by wet etching to adjust a height of the thin film portion, the upper part of the thin film portion being removed by using one of pure water and phosphoric acid.

Assignments (8)