Metal-insulator-metal (MIM) capacitor structure and methods of fabricating same

• US 6,717,193 B2
• Filed: 10/09/2001
• Issued: 04/06/2004
• Est. Priority Date: 10/09/2001
• Status: Expired due to Term

• Current Assignee: Akzo Nobel N.V. (Nouryon BV), NXP B.V. (NXP Semiconductors NV)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Olewine, Michael Charles, Saiz, Kevin F.
• Primary Examiner(s): Mai, Son L.
• Assistant Examiner(s): NGUYEN, DAO H
• Application Number:
  US09/973,640
• Publication Number:
  US 20030067023A1
• Time in Patent Office: 910 Days
• Field of Search: 257/295, 257/296, 257/534, 257/298, 257/306, 438/239, 438/240, 438/381
• US Class Current: 257/295
• CPC Class Codes: H01L 21/76834 formation of thin insulating films on the sidewalls or on top of conductors H01L21/76831 takes precedence
• CPC Class Codes: H01L 21/76852 the layer also covering the sidewalls of the conductive structure
• CPC Class Codes: H01L 23/5223 Capacitor integral with wiring layers
• CPC Class Codes: H01L 27/016 Thin-film circuits
• CPC Class Codes: H01L 28/60 Electrodes
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

A Metal-Insulator-Metal (MIM) capacitor structure and method of fabricating the same in an integrated circuit improve capacitance density in a MIM capacitor structure by utilizing a sidewall spacer extending along a channel defined between a pair of legs that define portions of the MIM capacitor structure. Each of the legs includes top and bottom electrodes and an insulator layer interposed therebetween, as well as a sidewall that faces the channel. The sidewall spacer incorporates a conductive layer and an insulator layer interposed between the conductive layer and the sidewall of one of the legs, and the conductive layer of the sidewall spacer is physically separated from the top electrode of the MIM capacitor structure. In addition, the bottom electrode of a MIM capacitor structure may be ammonia plasma treated prior to deposition of an insulator layer thereover to reduce oxidation of the electrode. Furthermore, a multi-rate etching process may be used to etch the top electrode and insulator layer of an MIM structure, using a first, higher rate to perform an anisotropic etch up to a point proximate an interface between the conductive and dielectric materials respectively defining the top electrode and insulator layer of the MIM structure, and then using a second, lower rate to perform an anisotropic etch to a point proximate an etch stop layer defined on the bottom electrode of the MIM structure.

Claims

1. A metal-insulator-metal (MIM) capacitor structure for use in an integrated circuit, the MIM capacitor structure comprising:

(a) first and second legs extending generally parallel to one another and defining a channel therebetween, each leg including top and bottom electrodes, an insulator layer interposed between the top and bottom electrodes, and a sidewall that faces the channel;

(b) a first sidewall spacer extending along the channel, the first sidewall spacer including a conductive layer and a dielectric insulator layer interposed between the conductive layer and the sidewall of the first leg, wherein the conductive layer of the first sidewall spacer is physically separated from the top electrode of the first leg;

(c) a second sidewall spacer extending along the channel, the second sidewall spacer including a conductive layer and a dielectric insulator layer interposed between the conductive layer and the sidewall of the second leg, wherein the conductive layer of the second sidewall spacer is physically separated from the top electrode of the second leg; and

(d) a dielectric material disposed in the channel and interposed between the conductive layers of the first and second sidewall spacers.

2. The MIM capacitor structure of claim 1, wherein the bottom electrode for the first leg comprises titanium nitride.

3. The MIM capacitor structure of claim 2, wherein the bottom electrode for the first leg further includes an interconnect layer upon which the titanium nitride is deposited.

4. The MIM capacitor structure of claim 3, wherein the titanium nitride includes an ammonia plasma treated surface.

5. The MIM capacitor structure of claim 2, wherein the insulator layer for the first leg, and the dielectric layer in the first sidewall spacer, each comprise a high dielectric constant material.

6. The MIM capacitor structure of claim 5, wherein the high dielectric constant material in the insulator layer for the first leg and the dielectric layer in the first sidewall spacer is tantalum pentoxide.

7. The MIM capacitor structure of claim 5, wherein the top electrode for the first leg includes titanium nitride.

8. The MIM capacitor structure of claim 1, wherein the first and second legs are define within a serpentine pattern.

9. The MIM capacitor structure of claim 1, wherein the serpentine pattern comprises at least one of a positive serpentine pattern and a negative serpentine pattern.

10. The MIM capacitor structure of claim 9, wherein the serpentine pattern comprises a positive serpentine pattern interleaved with a negative serpentine pattern.

11. A metal-insulator-metal (MIM) capacitor structure for use in an integrated circuit, the MIM capacitor structure comprising:

(a) a serpentine pattern including first and second legs extending generally parallel to one another and defining a channel therebetween, the serpentine pattern including a substantially co-planar top electrode, a substantially co-planar bottom electrode, and a substantially co-planar insulator layer interposed between the top and bottom electrodes, wherein the first leg includes a sidewall that faces the channel; and

(b) a sidewall spacer extending along the channel, the sidewall spacer including a conductive layer and a dielectric insulator layer interposed between the conductive layer and the sidewall of the first leg, wherein the conductive layer of the sidewall spacer is physically separated from the top electrode.

12. The MIM capacitor structure of claim 11, wherein the bottom electrode comprises titanium nitride.

13. The MIM capacitor structure of claim 12, wherein the bottom electrode further includes an interconnect layer upon which the titanium nitride is deposited.

14. The MIM capacitor structure of claim 13, wherein the titanium nitride includes an ammonia plasma treated surface.

15. The MIM capacitor structure of claim 11, wherein the insulator layer and the dielectric layer in the sidewall spacer, each comprise a high dielectric constant material.

16. The MIM capacitor structure of claim 15, wherein the high dielectric constant material in the insulator layer and the dielectric layer in the sidewall spacer is tantalum pentoxide.

17. The MIM capacitor structure of claim 15, wherein the top electrode includes titanium nitride.

18. The MIM capacitor structure of claim 11, wherein the serpentine pattern comprises at least one of a positive serpentine pattern and a negative serpentine pattern.

19. The MIM capacitor structure of claim 11, wherein the serpentine pattern comprises a positive serpentine pattern interleaved with a negative serpentine pattern.

20. The MIM capacitor structure of claim 11, wherein the sidewall spacer is a first sidewall spacer, and wherein the MIM capacitor structure further comprises:

(a) a second sidewall spacer extending along the channel, the second sidewall spacer including a conductive layer and a dielectric insulator layer interposed between the conductive layer and the sidewall of the second leg, wherein the conductive layer of the second sidewall spacer is physically separated from the top electrode, and

(b) a dielectric material disposed in the channel and interposed between the conductive layers of the first and second sidewall spacers.