Selective deposition of wcn barrier/adhesion layer for interconnect

Patent metadata

Field	Value
Publication number	US-2018286746-A1
Application number	US-201715474383-A
Country	US
Kind code	A1
Filing date	Mar 30, 2017
Priority date	Mar 30, 2017
Publication date	Oct 4, 2018
Grant date	—

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.

First claim

What is claimed is:

1 . A method comprising:
providing a substrate comprising a feature having a feature bottom and feature sidewalls, wherein the feature bottom comprises a cobalt surface and the feature sidewalls comprise silicon oxide or silicon nitride surfaces; and 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.

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

4 . The method of claim 3 , further comprising, 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.

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

6 . 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.

7 . The method of claim 6 , wherein the ALD process deposits the WCN film on the silicon oxide or silicon nitride surface of the field region.

8 . The method of claim 7 , 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.

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

10 . 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.

11 . The method of claim 10 , wherein exposing the substrate to a co-reactant comprises exposing the substrate to a plasma.

12 . The method of claim 10 , wherein the co-reactant is at least one of H 2 and NH 3 .

13 . The method of claim 10 , wherein the nitrogen-containing organo-tungsten compound is a tungsten bis(alkylimino)bis(alkylamino) compound.

14 . The method of claim 10 , wherein the organo-tungsten compound is selected from: W 2 (NMe 2 ) 6 , ethylcyclopentadienyl-dicarbonylnitrosyl-tungsten, methylcyclopentadienyl-dicarbonylnitrosyl-tungsten, and ethylcyclopentadienyl-tricarbonylhydridotungsten.

15 . 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).

16 . A method comprising:
providing a partially fabricated semiconductor device comprising exposed surfaces of cobalt and surrounding dielectric to a reactor; sequentially introducing a vapor phase nitrogen-containing organo-tungsten precursor and a reducing agent to the reactor; and exposing the partially fabricated semiconductor device to the vapor phase nitrogen-containing organo-tungsten precursor and reducing agent under conditions such that a tungsten carbon nitride film is selectively deposited on the exposed surfaces of cobalt.

17 . The method of claim 16 , wherein the surfaces of surrounding dielectric are silicon oxide or silicon nitride surfaces.

Assignees

• Lam Res Corp

Inventors

• Na Jeong-Seok
• Rathod Megha
• Lai Chiukin Steven
• Humayun Raashina

Classifications

• H10W20/4437

  the principal metal being a transition metal · CPC title

• H10P14/6939

  characterised by the metal · CPC title

• H10P14/6339 Primary

  deposition by cyclic CVD, e.g. ALD, ALE or pulsed CVD · CPC title

• H10P14/432

  using selective deposition · CPC title

• H10W20/4403

  based on metals, e.g. alloys, metal silicides (H10W20/4484 takes precedence) · CPC title