Selective deposition of WCN barrier/adhesion layer for interconnect

• US 10,283,404 B2
• Filed: 03/30/2017
• Issued: 05/07/2019
• Est. Priority Date: 03/30/2017
• Status: Active Grant

• Current Assignee: Lam Research Corporation
• Original Assignee: Lam Research Corporation
• Inventors: Na, Jeong-Seok, Rathod, Megha, Lai, Chiukin Steven, Humayun, Raashina
• Primary Examiner(s): Nicely, Joseph C.
• Application Number:
  US15/474,383
• Publication Number:
  US 20180286746A1
• Time in Patent Office: 768 Days
• CPC Class Codes: C23C 16/0245 by etching with a plasma
• CPC Class Codes: C23C 16/045 Coating cavities or hollow spaces, e.g. interior of tubes; Infiltration of porous substrates
• CPC Class Codes: C23C 16/36 Carbonitrides
• CPC Class Codes: C23C 16/45531 specially adapted for making ternary or higher compositions
• CPC Class Codes: C23C 16/45536 Use of plasma, radiation or electromagnetic fields
• CPC Class Codes: H01L 21/02175 characterised by the metal H01L21/02197 takes precedence
• CPC Class Codes: H01L 21/0228 deposition by cyclic CVD, e.g. ALD, ALE, pulsed CVD
• CPC Class Codes: H01L 21/28562 Selective deposition
• 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 21/76826 by contacting the layer with gases, liquids or plasmas
• CPC Class Codes: H01L 21/76843 formed in openings in a dielectric
• CPC Class Codes: H01L 21/76844 Bottomless liners
• CPC Class Codes: H01L 21/76865 Selective removal of parts of the layer H01L21/76844 takes precedence
• CPC Class Codes: H01L 21/76879 by selective deposition of conductive material in the vias, e.g. selective C.V.D. on semiconductor material, plating plating on semiconductors in general H01L21/288
• CPC Class Codes: H01L 23/5226 Via connections in a multilevel interconnection structure
• CPC Class Codes: H01L 23/53209 based on metals, e.g. alloys, metal silicides H01L23/53285 takes precedence
• CPC Class Codes: H01L 23/5329 Insulating materials

Abstract

Provided are methods of forming diffusion barriers and adhesion layers for interconnects such as cobalt (Co) interconnects or ruthenium (Ru) interconnects. The methods involve selective deposition of tungsten carbon nitride (WCN) films on the oxide surfaces of a feature including a Co surface. The selective growth of WCN on oxide allows the contact resistance at an interface such as a Co—Co interface or a Co—Ru interface to be significantly reduced while maintaining good film coverage, adhesion, and/or barrier properties on the sidewall oxide surfaces.

Claims

1. A method comprising:

providing a substrate comprising a feature having a feature bottom and feature sidewalls, wherein the feature bottom comprises an cobalt surface and the feature sidewalls comprise silicon oxide or silicon nitride surfaces;

performing multiple cycles of an atomic layer deposition (ALD) process to deposit a tungsten carbon nitride (WCN) film to line the feature sidewalls, wherein a thickness of the WCN film on the silicon oxide or silicon nitride surfaces of the feature sidewalls is at least twice as thick as a thickness of the WCN film on the cobalt surface of the feature bottom; and

further comprising, prior to performing the multiple cycles of the ALD deposition process, exposing the feature to a hydrogen-containing plasma and after exposing the feature to the hydrogen-containing plasma and prior to performing the multiple cycles of the ALD deposition process, exposing the feature to a nitrogen-containing plasma.

2. The method of claim 1, wherein the thickness of the WCN film on the silicon oxide or silicon nitride surfaces of the feature sidewalls is at least five times as thick as the thickness of the WCN film on the cobalt surface of the feature bottom.

3. The method of claim 1, further comprising, after depositing the WCN film, filling the feature with cobalt or ruthenium.

4. The method of claim 1, wherein the feature includes a feature opening and the substrate includes a field region adjacent to the feature opening, the field region having a silicon oxide or silicon nitride surface.

5. The method of claim 4, wherein the ALD process deposits the WCN film on the silicon oxide or silicon nitride surface of the field region.

6. The method of claim 5, wherein a thickness of the WCN film on the silicon oxide or silicon nitride surface of the field region is no more than 30% greater than a thickness of the WCN film on a silicon oxide or silicon nitride surface of the feature sidewalls.

7. The method of claim 1, wherein a thickness of the WCN film on the feature sidewalls varies no more than about 20%.

8. The method of claim 1, wherein each cycle of the ALD process comprises introducing a pulse of a nitrogen-containing organo-tungsten compound to adsorb on the feature sidewalls and exposing the substrate to a co-reactant to react with the adsorbed nitrogen-containing organo-tungsten compound.

9. The method of claim 8, wherein exposing the substrate to a co-reactant comprises exposing the substrate to a plasma.

10. The method of claim 8, wherein the co-reactant is at least one of H₂ and NH₃.

11. The method of claim 8, wherein the nitrogen-containing organo-tungsten compound is a tungsten bis(alkylimino)bis(alkylamino) compound.

12. The method of claim 1, wherein each cycle of the ALD process comprises introducing a pulse of an organo-tungsten compound to absorb on the feature sidewalls and exposing the substrate to a co-reactant to react with the adsorbed organo-tungsten compound wherein the organo-tungsten compound is selected from:

W₂(NMe₂)₆, ethylcyclopentadienyl-dicarbonylnitrosyl-tungsten, methylcyclopentadienyl-dicarbonylnitrosyl-tungsten, and ethylcyclopentadienyl-tricarbonylhydridotungsten.

13. The method of claim 1, wherein the WCN film has between 50 and 80% (atomic) tungsten (W), between 3 and 35% (atomic) carbon (C), and between 1 and 45% (atomic) nitrogen (N).

14. The method of claim 1, wherein each cycle of the ALD process comprises introducing a pulse of a nitrogen-containing organo-tungsten compound to adsorb on the feature sidewalls and exposing the substrate to a co-reactant to react with the adsorbed nitrogen-containing organo-tungsten compound.

15. A method comprising:

providing a substrate comprising a feature having a feature bottom and feature sidewalls, wherein the feature bottom comprises an cobalt surface and the feature sidewalls comprise silicon oxide or silicon nitride surfaces;

performing multiple cycles of an atomic layer deposition (ALD) process to deposit a tungsten carbon nitride (WCN) film to line the feature sidewalls, wherein a thickness of the WCN film on the silicon oxide or silicon nitride surfaces of the feature sidewalls is at least twice as thick as a thickness of the WCN film on the cobalt surface of the feature bottom; and

further comprising, prior to performing the multiple cycles of the ALD deposition process, exposing the feature to a hydrogen-containing plasma.

16. The method of claim 15, wherein the thickness of the WCN film on the silicon oxide or silicon nitride surfaces of the feature sidewalls is at least five times as thick as the thickness of the WCN film on the cobalt surface of the feature bottom.

17. The method of claim 15, further comprising, after depositing the WCN film, filling the feature with cobalt or ruthenium.

18. The method of claim 15, wherein the feature includes a feature opening and the substrate includes a field region adjacent to the feature opening, the field region having a silicon oxide or silicon nitride surface.

19. The method of claim 18, wherein the ALD process deposits the WCN film on the silicon oxide or silicon nitride surface of the field region.

20. The method of claim 19, wherein a thickness of the WCN film on the silicon oxide or silicon nitride surface of the field region is no more than 30% greater than a thickness of the WCN film on a silicon oxide or silicon nitride surface of the feature sidewalls.