Reducing contact resistance in vias for copper interconnects

Patent metadata

Field	Value
Publication number	US-10468296-B2
Application number	US-201715782421-A
Country	US
Kind code	B2
Filing date	Oct 12, 2017
Priority date	Jun 4, 2015
Publication date	Nov 5, 2019
Grant date	Nov 5, 2019

Abstract

A method of forming an electrical transmission structure that includes forming an opening through an interlevel dielectric layer to expose at least one electrically conductive feature and forming a shield layer on the opening. A gouge is formed in the electrically conductive feature through the opening using a subtractive method during which the shield layer protects the interlevel dielectric layer from being damaged by the subtractive method. A contact is formed within the opening in electrical communication with the at least one electrically conductive feature.

First claim

What is claimed is:

1. An interconnect structure comprising:
a contact present within an opening having at least two widths, wherein the contact extends into contact with an electrically conductive feature, wherein a gouge is present in an upper surface of the electrically conductive feature; and
a shield liner present on the sidewalls of the opening, wherein the shield liner includes discontinuous segments on each end of opposed ends of the opening and is defined only outside of the gouge after the contact is deposited.

2. The interconnect structure of claim 1 , wherein the electrically conductive feature is a metal line.

3. The interconnect structure of claim 1 , wherein the opening has a substantially circular or multi-sided cross section.

4. The interconnect structure of claim 1 , wherein the gouge includes angled sidewalls.

5. The interconnect structure of claim 1 , wherein the gouge includes a planar base.

6. The interconnect structure of claim 1 , wherein the gouge includes angled sidewalls.

7. The interconnect structure of claim 1 , wherein the gouge includes an apex at a base of the gouge.

8. The interconnect structure of claim 1 , wherein the shield liner is comprised of a dielectric material.

9. The interconnect structure of claim 1 , wherein the shield liner is comprised of an electrically conductive material.

10. The interconnect structure of claim 1 , wherein the shield liner has a thickness ranging from 3 nm to 150 nm.

11. The interconnect structure of claim 1 , further comprising a conformal metal nitride layer present on vertical and horizontal surfaces of the opening.

12. The interconnect structure of claim 1 , wherein the conformal metal nitride layer is present between the shield liner and an interlevel dielectric.

13. An interconnect structure comprising:
a contact present within an opening having at least two widths, wherein the contact extends into contact with an electrically conductive feature, wherein a gouge is present in an upper surface of the electrically conductive feature;
a metal nitride layer present on the sidewalls of the opening; and
a shield liner present on the metal nitride layer that is present on the sidewalls of the opening, wherein the shield liner includes discontinuous segments on each end of opposed ends of the opening and is defined only outside of the gouge after the contact is deposited.

14. The interconnect structure of claim 13 , wherein the electrically conductive feature is a metal line.

15. The interconnect structure of claim 13 , wherein the opening has a substantially circular or multi-sided cross section.

16. The interconnect structure of claim 13 , wherein the gouge includes angled sidewalls.

17. The interconnect structure of claim 13 , wherein the gouge includes a planar base.

18. The interconnect structure of claim 13 , wherein the gouge includes angled sidewalls.

19. The interconnect structure of claim 13 , wherein the gouge includes an apex at a base of the gouge.

20. The interconnect structure of claim 13 , wherein the shield liner is comprised of a dielectric material or is comprised of an electrically conductive material.

Assignees

• IBM

Inventors

• Murray Conal E
• Yang Chih-Chao

Classifications

• H10W20/4424

  Copper alloys · CPC title

• H10W20/425

  Barrier, adhesion or liner layers · CPC title

• H10W20/089

  using processes for implementing desired shapes or dispositions of the openings, e.g. double patterning · CPC title

• H10W20/076

  in via holes or trenches · CPC title

• H10W20/057

  by selectively depositing, e.g. by using selective CVD or plating · CPC title