Method of fabricating a semiconductor device
A conductive film is formed to extend from a bottom and a sidewall of a recess formed in an interlayer insulating film onto a top surface of the interlayer insulating film. Dry etching of the conductive film is performed such that a portion of the conductive film remains on the bottom and sidewall of the recess. The dry etching is also performed such that a deposition film is formed on a top portion of the recess.
1. A method of fabricating a semiconductor device, comprising:
forming an interlayer insulating film;
forming a recess in the interlayer insulating film;
forming a conductive film extending from a bottom and a sidewall of the recess onto a top surface of the interlayer insulating film such that a shape of an inner surface of the conductive film conforms with that of the recess; and
selectively removing a portion of the conductive film formed on the top surface of the interlayer insulating film by dry etching such that a portion of the conductive film remains on the bottom and sidewall of the recess,
wherein the dry etching is performed with forming a deposition film directly onto the inner surface of the conductive film including the bottom of the recess and with leaving a space surrounded by the deposition film in the recess such that a diameter of the space in an upper portion of the recess is smaller than a diameter of the space in a lower portion of the recess.
2. The method of fabricating a semiconductor device according to claim 1 , wherein the recess has an opening width of not more than 300 nm after the formation of the conductive film.
3. The method of fabricating a semiconductor device according to claim 2 , wherein the recess has a depth/opening width aspect ratio of not less than 5 after the formation of the conductive film.
4. The method of fabricating a semiconductor device according to claim 1 , wherein the dry etching is carried out by using an etching gas comprising at least a boron compound, while the deposition film comprises at least a compound of a component of the conductive film with boron.
5. The method of fabricating a semiconductor device according to claim 4 , wherein the dry etching is carried out by using an etching gas including BC13.
6. The method of fabricating a semiconductor device according to claim 5 , wherein the conductive film comprises TiN.
7. The method of fabricating a semiconductor device according to claim 6 , wherein the deposition film comprises boron and titanium.
8. The method of fabricating a semiconductor device according to claim 1 , wherein the dry etching includes:
removing the portion of the conductive film formed on the top surface of the interlayer insulating film; and
after the removing the portion of the conductive film, etching the top surface of the interlayer insulating film.
9. The method of fabricating a semiconductor device according to claim 8 ,
wherein the interlayer insulating film comprises at least a silicon oxide film or a silicon nitride film; and
wherein the etching the top surface of the interlayer insulating film is bias-applied etching.
10. The method of fabricating a semiconductor device according to claim 1 , further comprising removing the deposition film after the dry etching has been performed.
11. The method of fabricating a semiconductor device according to claim 1 , wherein the recess has a form of a hole.
12. The method of fabricating a semiconductor device according to claim 11 , wherein the portion of the conductive film which remains in the recess forms a lower electrode of a capacitor.
13. The method of fabricating a semiconductor device according to claim 1 , wherein the recess has a form of a trench.
14. The method of fabricating a semiconductor device according to claim 13 , wherein the portion of the conductive film which remains in the recess forms a guard-ring.
15. The method of fabricating a semiconductor device according to claim 1 , further comprising:
forming a capacitor contact plug electrically connected to the bottom of the conductive film;
removing the deposition film to expose the conductive film to be used for a lower capacitor electrode;
forming a capacitor insulating film on a surface of the lower capacitor electrode; and
forming an upper capacitor electrode on a surface of the capacitor insulating film.
16. The method of fabricating a semiconductor device according to claim 15 , further comprising after removing the deposition film, removing the interlayer insulating film.
17. The method of fabricating a semiconductor device according to claim 16 , wherein removing the interlayer insulating film is performed by wet etching.
18. A method, comprising:
forming an insulating layer;
selectively removing the insulating layer to form a hole in the insulating layer;
forming a conductive film extending from a bottom and a sidewall of the hole onto a top surface of the insulating layer; and
performing a dry etching to remove a portion of the conductive film formed on the top surface of the insulating layer with forming a deposition film onto an inner surface of the hole, the conductive film formed on the bottom of the hole being exposed to the dry etching, a thickness of the deposition film on an upper portion of the hole being larger than a thickness of the deposition film on a lower portion of the hole.
19. The method according to claim 18 , further comprising removing the deposition film after performing the dry etching.