ALD of tantalum using a hydride reducing agent

• US 7,144,806 B1
• Filed: 10/23/2002
• Issued: 12/05/2006
• Est. Priority Date: 10/23/2002
• Status: Active Grant

• Current Assignee: Novellus Systems Incorporated (Lam Research Corporation)
• Original Assignee: Novellus Systems Incorporated (Lam Research Corporation)
• Inventors: Taylor, Nerissa, Fair, James A., Sung, Jungwan
• Primary Examiner(s): Guerrero, Maria F.
• Application Number:
  US10/279,147
• Time in Patent Office: 1,504 Days
• Field of Search: 438/240, 438/627, 438/643, 438/648, 438/653, 438/656, 438/683, 438/687, 257/762
• US Class Current: 438/653
• CPC Class Codes: C23C 16/14 Deposition of only one other metal element
• CPC Class Codes: C23C 16/38 Borides
• CPC Class Codes: C23C 16/42 Silicides
• CPC Class Codes: C23C 16/45542 Plasma being used non-continuously during the ALD reactions
• CPC Class Codes: H01L 21/28562 Selective deposition
• CPC Class Codes: H01L 21/76843 formed in openings in a dielectric

Abstract

An ALD method deposits conformal tantalum-containing material layers on small features of a substrate surface. The method includes the following principal operations: depositing a thin conformal and saturated layer of tantalum-containing precursor over some or all of the substrate surface; using an inert gas or hydrogen plasma to purge the halogen byproducts and unused reactants; reducing the precursor to convert it to a conformal layer of tantalum or tantalum-containing material; using another purge of inert gas or hydrogen plasma to remove the halogen byproducts and unused reactants; and repeating the deposition/reduction cycles until a desired tantalum-containing material layer is achieved. An optional step of treating each newly formed surface of tantalum containing material with a nitrogen-containing agent can be added to create varying amounts of tantalum nitride.

Claims

1. A method of forming a layer of tantalum-containing material on a substrate, the method comprising:

(a) depositing from gas phase a tantalum-containing precursor onto the substrate to form an adsorbed saturated layer of the tantalum-containing precursor on the substrate, wherein the tantalum-containing precursor is deposited by a self-limiting reaction to form the adsorbed saturated layer;

(b) contacting the tantalum-containing precursor of the saturated layer with a boron hydride or a silicon hydride to form a tantalum-containing adhesion layer; and

(c) converting a portion of the tantalum-containing adhesion layer to a nitride diffusion barrier on the tantalum-containing adhesion layer to form a bilayer of a tantalum-containing adhesion layer and a nitride diffusion barrier,

where the tantalum-containing adhesion layer comprise one or more of tantalum metal, tantalum silicide and tantalum boride and wherein (a) and (b) comprise introducing the tantalum-containing precursor and the hydride alternately over the substrate.

2. The method of claim 1, further comprising contacting the tantalum-containing material with a hydrogen plasma to remove halogen atoms.

3. The method of claim 1, wherein the silicon hydride is SiH₄ or Si₂H₆.

4. The method of claim 1, wherein both (a) and (b) are performed at temperatures not greater than about 450°

C.

5. The method of claim 1, wherein the boron hydride is B₂H₆.

6. The method of claim 1, wherein the layer of tantalum-containing material comprises a tantalum silicide.

7. The method of claim 1, wherein the layer of tantalum-containing material comprises tantalum metal.

8. The method of claim 1, wherein the layer of tantalum-containing material is formed to a thickness of about three angstroms.

9. The method of claim 1, wherein (a) and (b) are repeated multiple times.

10. The method of claim 1, wherein the tantalum-containing adhesion layer is a tantalum silicide or a tantalum boride.

11. The method of claim 1, wherein the tantalum-containing adhesion layer comprises between about 15% and about 40% silicon.

12. The method of claim 1, further comprising repeating (a) and (b) to form an additional layer of tantalum-containing material.

13. The method of claim 1, wherein the tantalum-containing precursor is a tantalum halide.

14. The method of claim 1, wherein the substrate comprises a diffusion barrier layer on top of an oxide or a low-k dielectric in a semiconductor device.

15. The method of claim 1, further comprising contacting the layer of tantalum-containing material with a nitrogen-containing gas or nitrogen-containing plasma to form a tantalum nitride.

16. The method of claim 12, wherein the layer of tantalum-containing material is formed over multiple cycles to a total thickness of between about 5 and 50 angstroms.

17. The method of claim 13, wherein the tantalum halide is tantalum fluoride.

18. The method of claim 14, wherein the diffusion barrier layer is tantalum nitride.

19. The method of claim 14, wherein the diffusion barrier layer is titanium nitride.

20. The method of claim 15, wherein the nitrogen gas is NH₃.