Capacitor and method for fabricating the same

• US 20030063428A1
• Filed: 09/26/2002
• Published: 04/03/2003
• Est. Priority Date: 09/28/2001
• Status: Active Grant

• Current Assignee: Fujitsu Quantum Devices Limited (Fujitsu Limited)
• Original Assignee: Fujitsu Quantum Devices Limited (Fujitsu Limited)
• Inventors: Nishi, Masahiro
• Granted Patent: US 6,788,521 B2
• Time in Patent Office: Days
• US Class Current: 361/301.4
• CPC Class Codes: H01L 28/40 Capacitors
• CPC Class Codes: H01L 28/55 with a dielectric comprising a perovskite structure material

Abstract

The capacitor comprises: a lower electrode 12 formed on a substrate 10; an insulation film 16 having an opening 24 on the lower electrode 12; a capacitor dielectric film 30 formed on the lower electrode 12 in the opening 24 and having a larger thickness at a peripheral part of the opening 24 than at a central part of the opening; and an upper electrode 32 formed on the capacitor dielectric film 30. Thus, degradation of the breakdown voltage and stress resistance of the peripheral part of the opening 24, which is due to the coverage of the capacitor dielectric film, can be suppressed.

Claims

1. A capacitor comprising:

a lower electrode formed on a substrate;

an insulation film formed on the substrate with the lower electrode formed on, and having an opening on the lower electrode;

a capacitor dielectric film formed on the lower electrode in the opening, and having a larger film thickness at a peripheral part of the opening than at a central part of the opening; and

an upper electrode formed on the capacitor dielectric film.

6. A capacitor according to claim 1, wherein

the first insulation film is a cover insulation film which covers an interconnection or an electrode formed on the substrate in a region different from a region where the lower electrode is formed.

2. A capacitor comprising:

a lower electrode formed on a substrate;

a first insulation film formed on the substrate with the lower electrode formed on, and having a first opening on the lower electrode;

a second insulation film formed on the first insulation film, and having a second opening in a region where the first opening is formed;

a capacitor dielectric film formed on the lower electrode in the opening, and extended over the second insulation film; and

an upper electrode formed on the capacitor dielectric film.

3. A capacitor according to claim 2, wherein

the second opening is larger than the first opening, and an upper surface of the first insulation film is exposed at the peripheral part of the second opening.

4. A capacitor according to claim 3, wherein

a film thickness of the first insulation film in a region where the second opening is formed is thinner than that in a region below the second insulation film.

5. A capacitor according to claim 2, in which

the first opening and the second opening are formed in a region containing a region where the lower electrode is formed;

and which further comprises;

a sidewall insulation film formed on a side wall of the lower electrode, the sidewall insulation film being formed of the same insulation film as the first insulation film and spaced from the first insulation film.

7. A capacitor according to claim 2, wherein

the first insulation film is a cover insulation film which covers an interconnection or an electrode formed on the substrate in a region different from a region where the lower electrode is formed.

8. A method for fabricating a capacitor comprising the steps of:

forming a lower electrode on a substrate;

forming a first insulation film on the substrate with the lower electrode formed on;

forming a second insulation film on the first insulation film;

forming an opening reaching the lower electrode in the first insulation film and the second insulation film;

forming a capacitor dielectric film on the lower electrode, extended over the second insulation film; and

forming an upper electrode on the capacitor dielectric film.

9. A method for fabricating a capacitor according to claim 8, wherein

in the step of forming the opening, the opening is formed in the second insulation film in a larger opening diameter than in the first insulation film.

10. A method for fabricating a capacitor according to claim 9, wherein

the step of forming the opening includes the step of etching the second insulation film under a condition for forming a sidewall deposited film on the etched surface;

the step of etching the first insulation film with the second insulation film and the sidewall deposited film as a mask; and

the step of removing the sidewall deposited film.

11. A method for fabricating a capacitor according to claim 10, wherein

in the step of etching the second insulation film, the sidewall deposited film is formed by performing the etching in an atmosphere containing a carbon-content gas.

12. A method for fabricating a capacitor according to claim 9, wherein

the step of forming the opening includes the step of etching the second insulation film;

the step of etching the first insulation film with the second insulation film as a mask; and

the step of etching the second insulation film under a condition containing an isotropic etching component to thereby increase an opening diameter of the opening in the second insulation film.

13. A method for fabricating a capacitor according to claim 10, wherein

in the step of etching the first insulation film, the first insulation film is etched under a condition that an etching of the first insulation film progresses also lateral direction to thereby retreat sidewise the first insulation film.

14. A method for fabricating a capacitor according to claim 12, wherein

in the step of etching the first insulation film, the first insulation film is etched under a condition that an etching of the first insulation film progresses also lateral direction to thereby retreat sidewise the first insulation film.

15. A method for fabricating a capacitor according to claim 13, wherein

the sidewall deposited film is removed to thereby mitigate a sidewise retreat amount of the first insulation film.

16. A method for fabricating a capacitor according to claim 14, wherein

the sidewall deposited film is removed to thereby mitigate a sidewise retreat amount of the first insulation film.

17. A method for fabricating a capacitor according to claim 9, which further comprises, after the step of forming the second insulation film, the step of forming a third insulation film having an opening above the lower electrode;

and in which

the step of forming the opening includes the step of etching the second insulation film under a condition containing an isotropic etching component with the third insulation film as a mask; and

the step of etching the first insulation film with the third insulation film as a mask.

18. A method for fabricating a capacitor according to claim 17, wherein

in the step of etching the first insulation film, the etching is performed under a condition for etching the first insulation film and the third insulation film to thereby form the opening while removing the third insulation film.

19. A method for fabricating a capacitor according to claim 8, wherein

in the step of forming the opening, the opening is formed in a region containing a region for the lower electrode formed in.

20. A method for fabricating a capacitor according to claim 19, wherein

in the step of forming the opening, the opening is formed while the sidewall insulation film of the first insulation film is formed on the side wall of the lower electrode.