Structure including via having refractory metal collar at copper wire and dielectric layer liner-less interface and related method

• US 7,859,113 B2
• Filed: 02/27/2007
• Issued: 12/28/2010
• 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
• Primary Examiner(s): Lee; Hsien-ming
• Assistant Examiner(s): PARENDO, KEVIN A
• Application Number:
  US11/679,483
• Publication Number:
  US 20080203570A1
• Time in Patent Office: 1,400 Days
• Field of Search: 257/E21.579, 257/E21.585, 257/E23.145, 257/E23.152, 257/774, 438638-639
• US Class Current: 257/774
• 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;

a dielectric layer located above the liner-less interface of the metal wire;

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

a refractory metal collar extending from a side of the via and partially along the liner-less interface, the refractory metal collar having a slit-shaped cross section with a substantially uniform thickness extending downward from the liner-less interface and a substantially uniform width extending radially outward from the side of the via along the liner-less interface, wherein the substantially uniform thickness of the slit-shaped cross section is less than the substantially uniform width of the slit-shaped cross section; and

a first liner that is continuous about the via including the bottom of the via and the refractory metal collar, wherein the first liner is provided against an internal wall surface of the via including the bottom of the via, wherein a portion of the internal wall surface of the via is the surface of the dielectric layer, wherein the first liner runs continuously against the internal wall surface of the via as the via extends through the dielectric layer and the metal wire, wherein the first liner includes a second refractory metal that is the same as the refractory metal used in the refractory metal collar.

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 is 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 forming a second liner that is provided continuously against the first liner, the second liner including at least one metal diffusion barrier and a metal seed layer.

5. The structure of claim 4, 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.

6. The structure of claim 4, 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.

7. 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.

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

9. The structure of claim 1, wherein the first liner comprises a single liner layer.

10. The structure of claim 9, wherein the single liner layer is formed from a single deposition process.

11. A structure comprising:

a copper wire having a liner-less interface;

a dielectric layer located above the liner-less interface of the copper wire;

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

a first liner that is fully continuous around the via including the bottom of the via through the dielectric layer and the copper wire, wherein the first liner is provided against the internal wall surface of the via including the bottom of the via, wherein a portion of the internal wall surface of the via is the surface of the dielectric layer, wherein the first liner runs continuously against the internal wall surface of the via through the dielectric layer and the copper wire, wherein the first liner includes a refractory metal; and

a refractory metal collar extending from a side of the via and partially along the liner-less interface, the refractory metal collar comprising a slit-shaped cross section with a substantially uniform thickness extending downward from the liner-less interface and a substantially uniform width extending radially outward from the side of the via along the liner-less interface, wherein the substantially uniform thickness of the slit-shaped cross section is less than the substantially uniform width of the slit-shaped cross section, and wherein a second refractory metal used in the collar is the same as the refractory metal used in the first liner.

12. The structure of claim 11, wherein the second refractory metal 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).

13. The structure of claim 11, wherein the dielectric layer includes a barrier layer forming the liner-less interface with the copper wire and an interlevel dielectric above the barrier layer.

14. The structure of claim 11, wherein the first liner comprises a single liner layer.

15. The structure of claim 14, wherein the single liner layer is formed from a single deposition process.