Method of forming metal electrodes

• US 6,475,854 B2
• Filed: 12/21/2000
• Issued: 11/05/2002
• Est. Priority Date: 12/30/1999
• Status: Expired due to Fees

• Current Assignee: Applied Materials Incorporated
• Original Assignee: Applied Materials Incorporated
• Inventors: Upadhyaya, Deepak, Nickles, Annabel, Narwankar, Pravin K., Wang, Yaxin, Jin, Xiaoliang
• Primary Examiner(s): Niebling, John F.
• Assistant Examiner(s): Kennedy, Jennifer M.
• Application Number:
  US09/748,072
• Publication Number:
  US 20010043453A1
• Time in Patent Office: 684 Days
• Field of Search: 438/3, 438/240, 438/253, 438/396, 257/306, 257/310
• US Class Current: 438/238
• CPC Class Codes: H01L 28/55 with a dielectric comprising a perovskite structure material
• CPC Class Codes: H01L 28/75 comprising two or more layers, e.g. comprising a barrier layer and a metal layer

Abstract

A capacitor structure comprising a bottom electrode, an insulator and a top electrode, and method for manufacturing the same. The bottom and top electrodes preferably include a metal portion and a conducting oxygen-containing metal portion. In one embodiment, a layer of ruthenium is deposited to form a portion of the bottom electrode. Prior to deposition of the insulator, the ruthenium is annealed in an oxygen-containing environment. The insulator is then deposited on the oxygen-containing ruthenium layer. Formation of the top electrode includes depositing a first metal on the insulator, annealing the first metal and then depositing a second metal. The first and second metals may be ruthenium.

Claims

1. A method of forming a device on a substrate, comprising:

(a) forming a first metal layer on a substrate, wherein the first metal layer is formed by depositing a first metal-containing seed layer, treating the first metal-containing seed layer to reduce the oxygen content therein, and depositing a first metal bulk layer on the treated first metal-seed layer;

(b) exposing the first metal layer to a first oxygen-containing environment to form a first conducting oxygen-containing layer;

(c) forming an insulator on the first conducting oxygen-containing layer;

(d) forming a second metal layer on the insulator;

(e) exposing the second metal layer to a second oxygen-containing environment to form a second conducting oxygen-containing layer; and

(f) forming a third metal layer on the second conducting oxygen-containing layer.

2. The method of claim 1, wherein (a) comprises depositing ruthenium.

3. The method of claim 1, wherein (a), (d) and (f) comprise depositing ruthenium.

4. The method of claim 1, wherein (a) comprises depositing ruthenium and (b) comprises exposing the first metal layer to an oxygen-containing gas and heating the substrate.

5. The method of claim 1, wherein (c) comprises forming a tantalum pentoxide (Ta₂O₅) layer.

6. The method of claim 1, wherein (c) comprises depositing a material having a dielectric constant greater than about 20.

7. The method of claim 1, wherein (a), (d) and (f) comprise depositing ruthenium, (b) comprises exposing the first metal layer to an oxygen-containing gas, (c) comprises forming a tantalum pentoxide (Ta₂ O₅) layer, and (e) comprises exposing the second metal layer to an oxygen-containing gas.

8. The method of claim 7, wherein the oxygen-containing gas is selected from a group comprising nitrous oxide (N₂O), oxygen (O₂) and combinations thereof.

9. A method of forming a device on a substrate, comprising:

(a) depositing a first ruthenium layer on the substrate, wherein the first ruthenium layer is deposited by forming a ruthenium-containing seed layer and thereafter forming a ruthenium layer on the ruthenium-containing seed layer by chemical vapor deposition, and wherein the ruthenium-containing seed layer further comprises oxygen, and prior to depositing the ruthenium layer thereon, the ruthenium-containing seed layer is subjected to a treatment step for reducing the oxygen content therein;

(b) heating the substrate;

(c) exposing the first ruthenium layer to an oxygen-containing gas;

(d) depositing an insulating material;

(e) depositing the first metal layer on the insulating material;

(f) exposing the first metal layer to an oxygen-containing gas; and

(g) after (f), depositing a second metal layer.

10. The method of claim 9, at least one of (e) and (g) comprise depositing ruthenium.

11. The method of claim 9, wherein (c) and (f) comprise forming a conducting oxygen-containing layer.

12. The method of claim 9, wherein (d) comprises depositing a tantalum pentoxide (Ta₂O₅) layer.

13. The method of claim 12, wherein (d) further comprises annealing the tantalum pentoxide layer.

14. The method of claim 9, wherein (b) comprises heating the substrate to a temperature between about 200°

C and about 900°

C.

15. The method of claim 9, wherein (b) comprises heating the substrate to a temperature between about 200°

C and about 900°

C, (d) comprises depositing a Ta₂O₅ layer, and (e) comprises depositing a second ruthenium layer.

16. A method of forming a memory cell, comprising

(a) forming a first electrode on a substrate,

(b) forming a dielectric layer on the first electrode;

and

(c) forming a second electrode on the dielectric layer;

wherein at least one of the first electrode and the second electrode comprises a metal layer and a conductive oxygen-containing layer, wherein the conductive oxygen-containing layer is adjacent to the dielectric layer, and wherein the metal layer is formed by depositing a metal-containing seed layer, treating the metal-containing seed layer in an environment to reduce the oxygen content thereof and depositing a bulk metal layer on the treated metal-containing seed layer using a chemical vapor deposition process.

17. The method of claim 16, wherein the metal layer comprises ruthenium.

18. The method of claim 16, wherein the metal layer is a ruthenium layer and the conductive oxygen-containing layer is an oxygen-containing ruthenium layer.

19. The method of claim 16, wherein the first electrode comprises a metal selected from the group consisting of ruthenium, iridium and platinum.

20. The method of claim 16, wherein the metal-containing seed layer is treated in the presence of a plasma.

21. The method of claim 16, wherein the second electrode is selected from the group consisting of ruthenium, iridium, platinum and titanium nitride.

22. The method of claim 16, wherein the dielectric material is tantalum pentoxide.

23. The method of claim 16, further comprising, prior to (c), treating the dielectric material in an oxygen-containing environment.

24. A computer storage medium containing a software routine that, when executed, causes a genera purpose computer to control a deposition chamber using a method of thing film deposition, comprising:

(a) forming a first metal layer on a substrate, wherein the first metal layer is formed by depositing a first metal-containing seed layer, treating the first metal-containing seed layer to reduce the oxygen content therein, and depositing a first metal bulk layer on the treated first metal-seed layer;

(b) exposing the first metal layer to a first oxygen-containing environment to form a first conducting oxygen-containing layer'"'"'

(c) forming an insulator on the first conducting oxygen-containing layer;

(d) forming a second metal layer on the insulator;

(e) exposing the second metal layer to a second oxygen-containing environment to form a second conducting oxygen-containing layer; and

(f) forming a third metal layer on the second conducting oxygen-containing layer.

25. A method of forming a device on a substrate, comprising:

(a) depositing a first ruthenium layer on the substrate, wherein the first ruthenium layer is deposited by forming a ruthenium-containing seed layer and thereafter forming a ruthenium layer on the ruthenium-containing seed layer by chemical vapor deposition;

(b) heating the substrate;

(c) exposing the first ruthenium layer to an oxygen-containing gas;

(d) depositing an insulating material;

(e) depositing the first metal on the insulating material;

(f) exposing the first metal layer to an oxygen-containing gas; and

(g) after (f), depositing a second layer.

26. A method of forming a memory cell, comprising:

(a) forming a first electrode on a substrate,

(b) forming a dielectric layer on the first electrode; and

(c) forming a second electrode on the dielectric layer;

wherein at least one of the first electrode and the second electrode comprises a metal layer and a conductive oxygen-containing layer; and

wherein the first electrode is formed by;

forming a ruthenium-containing seed layer;

treating the ruthenium-containing seed layer in an oxygen-containing environment; and

forming a ruthenium layer on the treated ruthenium-containing seed layer by chemical vapor deposition.

27. The method of claim 26, wherein treating the ruthenium-containing seed layer in an oxygen-containing environment is performed in the presence of a plasma.