STRUCTURE INCLUDING VIA HAVING REFRACTORY METAL COLLAR AT COPPER WIRE AND DIELECTRIC LAYER LINER-LESS INTERFACE AND RELATED METHOD

• US 20080203570A1
• Filed: 02/27/2007
• Published: 08/28/2008
• Est. Priority Date: 02/27/2007
• Status: Active Grant

• Current Assignee: Taiwan Semiconductor Manufacturing Company Limited
• Original Assignee: International Business Machines Corporation
• Inventors: Yang, Chih-Chao, Nogami, Takeshi, Wang, Yun-Yu, Edelstein, Daniel C., Wang, Ping-Chuan
• Granted Patent: US 7,859,113 B2
• Time in Patent Office: Days
• US Class Current: 257/751
• CPC Class Codes: H01L 21/76805 the opening being a via or contact hole penetrating the underlying conductor
• CPC Class Codes: H01L 21/76814 post-treatment or after-treatment, e.g. cleaning or removal of oxides on underlying conductors
• CPC Class Codes: H01L 21/76843 formed in openings in a dielectric
• CPC Class Codes: H01L 21/76849 the layer being positioned on top of the main fill metal
• 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 23/5329 Insulating materials
• 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

Structures including a refractory metal collar at a copper wire and dielectric layer liner-less interface, and a related method, are disclosed. In one embodiment, a structure includes a copper wire having a liner-less interface with a dielectric layer thereabove; a via extending upwardly from the copper wire through the dielectric layer; and a refractory metal collar extending from a side of the via and partially along the liner-less interface. Refractory metal collar prevents electromigration induced slit voiding by improving the interface around the via, and prevents void nucleation from occurring near the via. Also, the refractory metal collar provides electrical redundancy in the presence of voids around the via and dielectric layer liner-less interface.

Claims

1. A structure comprising:

a metal wire having a liner-less interface with a dielectric layer and an interlevel dielectric thereabove;

a via extending upwardly from the metal wire through the dielectric layer and interlevel dielectric; and

a refractory metal collar extending from a side of the via and partially along the liner-less interface.

2. The structure of claim 1, wherein the via includes a substantially frusto-conical portion within the metal wire.

3. The structure of claim 1, wherein the refractory metal collar includes a material selected from a group consisting of at least one of:

tantalum (Ta), titanium (Ti), tungsten (W), ruthenium (Ru), iridium (Ir), rhodium (Rh) and platinum (Pt).

4. The structure of claim 1, further comprising a first liner about the via, the first liner including the refractory metal.

5. The structure of claim 4, further comprising forming a second liner about the via, the second liner including at least one metal diffusion barrier and a metal seed layer.

6. The structure of claim 5, wherein the at least one metal diffusion barrier is selected from a group consisting of:

tantalum, tantalum nitride, titanium, titanium nitride, tungsten, tungsten nitride, ruthenium and ruthenium nitride.

7. The structure of claim 5, wherein the metal wire includes copper and the metal seed layer is selected from a group consisting of at least one of:

copper, copper aluminum, copper iridium, copper nickel and copper ruthenium.

8. The structure of claim 1, wherein the metal wire is positioned within another dielectric layer, and further comprising a liner between the metal wire and the another dielectric layer.

9. The structure of claim 1, wherein the dielectric layer includes a barrier layer forming the liner-less interface with the metal wire, and the interlevel dielectric above the barrier layer.

10. A method comprising:

providing a metal wire in a first dielectric layer;

forming a second dielectric layer over the metal wire to form a liner-less interface between the metal wire and the second dielectric layer;

forming an opening through the second dielectric layer and into the metal wire;

creating an undercut from the opening under the second dielectric layer;

forming a refractory metal collar in the undercut; and

filling the opening with a metal to form a via.

11. The method of claim 10, wherein the providing includes providing a liner between the metal wire and the first dielectric layer along only a bottom and sides of the metal wire.

12. The method of claim 10, wherein the opening forming includes performing a damascene process to form the opening in the first dielectric layer, and performing a gaseous sputtering process to extend the opening into the metal wire.

13. The method of claim 10, wherein the undercut creating includes performing an isotropic wet/dry etching.

14. The method of claim 10, further comprising forming a first liner within the opening prior to the filling, the first liner including the refractory metal.

15. The method of claim 14, further comprising forming a second liner within the opening prior to the filling, the second liner including at least one metal diffusion barrier and a metal seed layer.

16. The method of claim 15, wherein the at least one metal diffusion barrier is selected from a group consisting of:

tantalum, tantalum nitride, titanium, titanium nitride, tungsten, tungsten nitride, ruthenium and ruthenium nitride.

17. The method of claim 15, wherein the metal wire includes copper and the metal seed layer is selected from a group consisting of at least one of:

copper, copper aluminum, copper iridium, copper nickel and copper ruthenium.

18. A structure comprising:

a copper wire having a liner-less interface with a dielectric layer and an interlevel dielectric thereabove;

a via extending upwardly from the copper wire through the dielectric layer and interlevel dielectric, the via including a substantially frusto-conical portion within the copper wire;

a first liner about the via, the first liner including a refractory metal; and

a refractory metal collar extending from a side of the via and partially along the liner-less interface.

19. The structure of claim 18, wherein the refractory metal collar includes a material selected from a group consisting of at least one of:

tantalum (Ta), titanium (Ti), tungsten (W), ruthenium (Ru), iridium (Ir), rhodium (Rh) and platinum (Pt).

20. The structure of claim 18, wherein the dielectric layer includes a barrier layer forming the liner-less interface with the copper wire, and the interlevel dielectric above the barrier layer.