METHOD TO RESOLVE HOLLOW METAL DEFECTS IN INTERCONNECTS

• US 20130307151A1
• Filed: 05/16/2012
• Published: 11/21/2013
• Est. Priority Date: 05/16/2012
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Bonilla, Griselda, Bao, Junjing, Choi, Samuel S., Filippi, Ronald G., Lustig, Naftali E., Simon, Andrew H.
• Granted Patent: US 9,034,664 B2
• Time in Patent Office: Days
• US Class Current: 257/750
• CPC Class Codes: H01L 21/76832 Multiple layers
• 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 23/5283 Cross-sectional geometry
• 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 of repairing hollow metal void defects in interconnects and resulting structures. After polishing interconnects, hollow metal void defects become visible. The locations of the defects are largely predictable. A repair method patterns a mask material to have openings over the interconnects (and, sometimes, the adjacent dielectric layer) where defects are likely to appear. A local metal cap is formed in the mask openings to repair the defect. A dielectric cap covers the local metal cap and any recesses formed in the adjacent dielectric layer.

Claims

1. The method of repairing an interconnect, the method comprising:

forming a mask;

opening the mask over a first portion of an interconnect and over a dielectric layer adjacent the first portion of the interconnect thereby forming a recess in the dielectric layer;

forming a local metal cap on the first portion of the interconnect; and

forming a dielectric cap.

2. The method of claim 1, wherein forming a local metal cap at least partially fills a void in the first portion of the interconnect.

3. The method of claim 1, wherein forming the local metal cap is by selective deposition.

4. The method of claim 1, wherein the local metal cap comprises cobalt.

5. The method of claim 1, wherein the dielectric cap a least partially fills the recess in the dielectric layer, and wherein the dielectric cap is above and in contact with the local metal cap.

6. The method of claim 1, wherein the dielectric cap comprises nitrogen.

7. The method of claim 1, wherein the mask and the dielectric cap are made of the same material.

8. The method of claim 1, further comprising forming a via above the interconnect wherein the via lands on the interconnect.

9. The method of claim 8, wherein the via at least partially lands on the local metal cap.

10. A structure comprising:

an interconnect having a first portion wherein the first portion has a local metal cap;

a dielectric layer adjacent the interconnect, wherein the dielectric layer has a recess abutting the first portion of the interconnect.

11. The structure of claim 10 wherein in the first portion is an end portion of the interconnect.

12. The structure of claim 10 wherein in the local metal cap is in a defect in the interconnect.

13. The structure of claim 10 wherein the local metal cap comprises cobalt.

14. The structure of claim 10 wherein the recess of the dielectric layer is filled with a dielectric cap.

15. The structure of claim 14 wherein the cap dielectric comprises nitrogen.

16. The structure of claim 15 wherein the dielectric cap is above and in contact with the local metal cap.

17. The structure of claim 10 further comprising a second portion of the interconnect wherein the second portion lacks the local metal cap.

18. The structure of claim 17 further comprising a mask above and in contact with the second portion.

19. The structure of claim 18 wherein the mask is made of the same material as the cap dielectric.

20. A structure comprising:

an interconnect having a first portion and a second portion, wherein the first portion has a local metal and the second portion lacks a local metal.