ENHANCED MECHANICAL STRENGTH VIA CONTACTS

• US 20070284736A1
• Filed: 05/18/2006
• Published: 12/13/2007
• Est. Priority Date: 05/18/2006
• Status: Active Grant

• Current Assignee: GlobalFoundries, Inc.
• Original Assignee: International Business Machines Corporation
• Inventors: Chen, Shyng-Tsong, Yang, Chih-Chao, Malone, Kelly, Bonilla, Griselda
• Granted Patent: US 7,439,624 B2
• Time in Patent Office: Days
• US Class Current: 257/734
• CPC Class Codes: H01L 21/76844 Bottomless liners
• CPC Class Codes: H01L 21/76847 the layer being positioned within the main fill metal
• CPC Class Codes: H01L 21/76877 Filling of holes, grooves or trenches, e.g. vias, with conductive material
• CPC Class Codes: H01L 23/5226 Via connections in a multilevel interconnection structure
• CPC Class Codes: H01L 23/53223 Additional layers associated with aluminium layers, e.g. adhesion, barrier, cladding layers
• CPC Class Codes: H01L 23/53238 Additional layers associated with copper layers, e.g. adhesion, barrier, cladding layers
• CPC Class Codes: H01L 23/53295 Stacked insulating 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

The present invention provides an enhanced interconnect structure with improved reliability. The inventive interconnect structure has enhanced mechanical strength of via contacts provided by embedded metal liners. The embedded metal liners may be continuous or discontinuous. Discontinuous embedded metal liners are provided by a discontinuous interface at the bottom of the via located within the interlayer dielectric layer.

Claims

1. An interconnect structure comprising:

a first dielectric layer having at least one metallic interconnect embedded therein;

a second dielectric layer located atop said first dielectric layer, wherein said second dielectric layer has at least one aperture having an upper line region and a lower via region;

a first liner located atop the vertical and horizontal walls of said at least one aperture and said at least one metallic interconnect;

a first conductive material partially filling said at least one aperture;

a second liner located atop the remaining vertical and horizontal walls of said at least one aperture and said first conductive material; and

a second conductive material filling said remaining vertical and horizontal walls of said at least one aperture.

2. The interconnect structure of claim 1 wherein said metallic interconnect comprises a conductive metal or metal alloy.

3. The interconnect structure of claim 2 wherein said metal is Cu, W or Al.

4. The interconnect structure of claim 1 wherein said metallic interconnect comprises Cu.

5. The interconnect structure of claim 1 wherein said first dielectric layer has a dielectric constant of about 4.0 or less.

6. The interconnect structure of claim 5 wherein said first dielectric layer comprises SiO₂, a polyarylene resin, or an organosilicate glass.

7. The interconnect structure of claim 1 further comprising a patterned cap layer on a surface of said first dielectric layer, said patterned cap layer having an opening that exposes a surface portion of said metallic interconnect.

8. The interconnect structure of claim 7 wherein said patterned cap layer comprises a silicon nitride, silicon oxynitride, silicon carbide, or a combination thereof.

9. The interconnect structure of claim 1 wherein said second dielectric layer has a dielectric constant of about 4.0 or less.

10. The interconnect structure of claim 9 wherein said second dielectric layer comprises SiO₂, a polyarylene resin, or an organosilicate glass.

11. The interconnect structure of claim 1 further comprising a patterned hard mask on a surface of said second dielectric layer.

12. The interconnect structure of claim 11 wherein said patterned hard mask comprises a nitride, oxynitride or a combination thereof.

13. The interconnect structure of claim 1 wherein said first and second liners comprise the same or different diffusion resistant material selected from the group consisting of refractory metals, refractory metal nitrides, Ru, RuTa, RuTaN, Ir, Rh, Pt and TiNSi.

14. The interconnect structure of claim 1 wherein said first liner extends over a surface portion of the metallic interconnect.

15. The interconnect structure of claim 1 wherein said first liner is substantially absent from a bottom wall of said lower via region.

16. The interconnect structure of claim 1 wherein said first and second conductive materials are selected from a group consisting of Cu, Al and CuAl.

17. The interconnect structure of claim 1 wherein said first and second conductive materials comprise Cu.

18. The interconnect structure of claim 1 further comprising a third conductive material partially filling said at least one aperture;

and

a third liner located atop the remaining vertical and horizontal walls of said at least one aperture and said third conductive material.

19. The interconnect structure of claim 18 further comprising multiple conductive material partially filling said at least one aperture;

and

multiple liners embedded in the interconnect structure atop said multiple conductive material partially filling said at least one aperture.

20. An interconnect structure comprising:

a first dielectric layer having at least one metallic interconnect embedded therein;

a second dielectric layer located atop said first dielectric layer, wherein said second dielectric layer has at least one aperture having an upper line region and a lower via region;

a first liner located atop the vertical and horizontal walls of said at least one aperture and said at least one metallic interconnect;

a first conductive material partially filling said at least one aperture;

a second liner located atop the remaining vertical and horizontal walls of said at least one aperture and said first conductive material, said second liner being discontinuous on said horizontal wall; and

a second conductive material filling said remaining vertical and horizontal walls of said at least one aperture.

21. The interconnect structure of claim 20 further comprising a third conductive material partially filling said at least one aperture;

and

a third liner located atop the remaining vertical and horizontal walls of said at least one aperture and said third conductive material.

22. The interconnect structure of claim 21 further comprising multiple conductive material partially filling said at least one aperture;

and

multiple liners embedded in the interconnect structure atop said multiple conductive material partially filling said at least one aperture.

23. A method of forming an interconnect structure having an embedded liner comprising the steps of:

forming a second dielectric layer atop a first dielectric layer having a metallic interconnect embedded therein;

forming at least one aperture within said second dielectric layer that extends to the metallic interconnect in said first dielectric layer;

forming a first liner material in said at least one aperture;

partially forming a first conductive material in said at least one aperture;

forming a second liner in the remaining portion of said at least one aperture and said first conductive material; and

forming a second conductive material in said at least one aperture.

24. The method of claim 23 wherein said forming said at least one aperture comprises forming a via opening and a line opening, wherein said via opening is formed prior to said line opening.

25. The method of claim 23 wherein said forming said at least one aperture comprises forming a via opening and a line opening, wherein said line opening is formed prior to said via opening.

26. The method of claim 23 wherein a patterned cap layer is formed on a surface of said first dielectric layer prior to forming said second dielectric layer.

27. The method of claim 23 further comprising forming a patterned hard mask atop said second dielectric layer prior to said forming said at least one aperture.

28. The method of claim 23 wherein said metallic interconnect and said conductive material both comprise Cu.

29. A method of forming an interconnect structure having an embedded liner comprising the steps of:

forming a second dielectric layer atop a first dielectric layer having a metallic interconnect embedded therein;

forming at least one aperture within said second dielectric layer that extends to the metallic interconnect in said first dielectric layer;

forming a first liner material in said at least one aperture;

partially forming a first conductive material in said at least one aperture;

forming a second liner in the remaining portion of said at least one aperture and said first conductive material;

partially removing said second liner material at a bottom surface of said at least one aperture to create a discontinuous interface, while simultaneously depositing a second discontinuous liner; and

forming a second conductive material in said at least one aperture.

30. The method of claim 29 wherein said partially removing said liner material and simultaneous deposition includes ion bombardment and sputtering.

31. The method of claim 30 wherein said ion bombardment includes one of Ar, He, Ne, Xe, N₂, H₂, NH₃ or N₂H₂.

32. The method of claim 30 wherein said ion bombardment leaves a portion of said first liner on a bottom wall of said via so as to form said discontinuous interface.

33. The method of claim 29 wherein said step of partially removing said liner material and simultaneous deposition is repeated at least once.

34. The method of claim 29 further comprising a sputter process which is performed after said partially removing said liner material and simultaneous deposition step.