Capping of Copper Interconnect Lines in Integrated Circuit Devices

• US 20110108990A1
• Filed: 11/06/2009
• Published: 05/12/2011
• Est. Priority Date: 11/06/2009
• Status: Active Grant

• Current Assignee: Globalfoundries US Incorporated (GlobalFoundries, Inc.)
• Original Assignee: International Business Machines Corporation
• Inventors: Standaert, Theodorus E., Rath, David L., Sankaran, Sujatha, Simon, Andrew H., Bonilla, Griselda, Filippi, Ronald G., Yang, Chih-Chao, Grunow, Stephan, Chanda, Kaushik
• Granted Patent: US 8,298,948 B2
• Time in Patent Office: Days
• US Class Current: 257/761
• 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 21/76849 the layer being positioned on top of the main fill metal
• CPC Class Codes: H01L 21/76865 Selective removal of parts of the layer H01L21/76844 takes precedence
• CPC Class Codes: H01L 23/53238 Additional layers associated with copper layers, e.g. adhesion, barrier, cladding layers
• 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 method for capping lines includes forming a metal film layer on a copper line by a selective deposition process, the copper line disposed in a dielectric substrate, wherein the depositing also results in the deposition of stray metal material on the surface of the dielectric substrate, and etching with an isotropic etching process to remove a portion of the metal film layer and the stray metal material on the surface of the dielectric substrate, wherein the metal film layer is deposited at an initial thickness sufficient to leave a metal film layer cap remaining on the copper line following the removal of the stray metal material.

Claims

1. A method for capping lines, the method comprising:

forming a metal film layer on a copper line by a selective deposition process, the copper line disposed in a dielectric substrate, wherein the depositing also results in the deposition of stray metal material on the surface of the dielectric substrate; and

etching with an isotropic etching process to remove a portion of the metal film layer and the stray metal material on the surface of the dielectric substrate;

wherein the metal film layer is deposited at an initial thickness sufficient to leave a metal film layer cap remaining on the copper line following the removal of the stray metal material.

2. The method of claim 1, wherein the method further comprises depositing a layer of dielectric material on the metal film layer and the dielectric substrate after etching with the isotropic etching process.

3. The method of claim 1, wherein the metal film layer is one of:

Cobalt Tungsten phosphide (CoWP), tantalum (Ta), and Ruthenium (Ru).

4. The method of claim 1, wherein the dielectric substrate is a carbon doped oxide.

5. The method of claim 1, wherein the deposited metal film layer has a thickness between 100 and 200 angstroms.

6. The method of claim 1, wherein the deposited metal film layer has a thickness between 200 and 300 angstroms.

7. The method of claim 1, wherein the resultant metal film layer has a center portion between 10 and 100 angstroms thick.

8. The method of claim 7, wherein the resultant metal film layer has edge portions between 10 and 100 angstroms thick and less than the thickness of the center portion.

9. The method of claim 1, wherein the resultant metal film layer has an arcuate profile.

10. A method for capping lines, the method comprising:

depositing a metal film layer having a thickness on a copper line, the copper line disposed in a dielectric substrate, wherein the depositing results in the deposition of stray metal material on the surface of the dielectric substrate; and

etching with an anisotropic etching process to remove a portion of the metal film layer and the stray metal material on the surface of the dielectric substrate;

wherein the metal film layer is deposited at an initial thickness sufficient to leave a metal film layer cap remaining on the copper line following the removal of the stray metal material.

11. The method of claim 10, wherein the method further comprises depositing a layer of dielectric material on the metal film layer and the dielectric substrate after etching with an anisotropic etching process to remove a portion of the metal film layer and the stray metal material on the surface of the dielectric substrate.

12. The method of claim 10, wherein the metal film layer is one of:

Cobalt Tungsten phosphide (CoWP), tantalum (Ta), and Ruthenium (Ru).

13. The method of claim 10, wherein the dielectric substrate is a carbon doped oxide.

14. The method of claim 10, wherein the deposited metal film layer is between 100 and 200 angstroms.

15. The method of claim 10, wherein the deposited metal film layer is between 200 and 300 angstroms.

16. The method of claim 10, wherein the resultant metal film layer is between 50 and 150 angstroms thick.

17. A capped copper line assembly comprising:

a copper line disposed in a dielectric substrate;

a metal film layer having arcuate profile, wherein a center portion of the metal film layer has a first thickness greater than a second thickness of edges of the metal film layer;

a dielectric layer disposed on the dielectric substrate and the metal film layer.

18. The capped copper line assembly of claim 17, wherein the metal film layer is one of:

Cobalt Tungsten phosphide (CoWP), tantalum (Ta), and Ruthenium (Ru).

19. The capped copper line assembly of claim 17, wherein the metal film layer has a center portion between 10 and 100 angstroms thick.

20. The capped copper line assembly of claim 19, wherein the metal film layer has edge portions between 10 and 100 angstroms thick.