Method for void-free cobalt gap fill

Patent metadata

Field	Value
Publication number	US-2016056077-A1
Application number	US-201514873152-A
Country	US
Kind code	A1
Filing date	Oct 1, 2015
Priority date	Aug 21, 2014
Publication date	Feb 25, 2016
Grant date	—

Abstract

Provided herein are methods of depositing void-free cobalt into features with high aspect ratios. Methods involve (a) partially filling a feature with cobalt, (b) exposing the feature to a plasma generated from nitrogen-containing gas to selectively inhibit cobalt nucleation on surfaces near or at the top of the feature, optionally repeating (a) and (b), and depositing bulk cobalt into the feature by chemical vapor deposition. Methods may also involve exposing a feature including a barrier layer to a plasma generated from nitrogen-containing gas to selectively inhibit cobalt nucleation. The methods may be performed at low temperatures less than about 400° C. using cobalt-containing precursors. Methods may also involve using a remote plasma source to generate the nitrogen-based plasma. Methods also involve annealing the substrate.

First claim

What is claimed is:

1 . A method of processing a semiconductor substrates, the method comprising:
(a) providing a substrate having one or more features, each feature comprising a feature opening; (b) selectively inhibiting cobalt nucleation on surfaces of the one or more features that are at or near the feature openings such that there is a differential inhibition profile in each feature; and (c) exposing the substrate to a cobalt-containing precursor to partially fill the one or more features, wherein selectively inhibiting cobalt nucleation further comprises exposing the substrate to plasma generated from a nitrogen-containing gas in a remote plasma source.

2 . The method of claim 1 , further comprising depositing cobalt in the one or more features in accordance with the differential inhibition profile.

3 . The method of claim 1 , further comprising repeating (b) and (c) in two or more cycles to deposit cobalt into the one or more features.

4 . The method of claim 1 , further comprising annealing the substrate after partially filling the one or more features.

5 . The method of claim 3 , further comprising annealing the substrate after partially filling the one or more features, wherein the substrate is annealed after each of the two or more cycles.

6 . The method of claim 4 , wherein the annealing is performed when an amount of cobalt deposited in at least one of the one or more features is between about 20% and about 60% of the at least one of the one or more features.

7 . The method of claim 4 , further comprising after annealing the substrate, electroplating copper or performing electroless plating of copper onto the substrate.

8 . The method of claim 2 , wherein the cobalt is deposited by chemical vapor deposition, atomic layer deposition, or a combination thereof.

9 . The method of claim 2 , wherein the cobalt is deposited by electroplating or electroless plating.

10 . The method of claim 4 , wherein the substrate is annealed at a temperature between about 250° C. and about 500° C.

11 . The method of claim 1 , further comprising prior to selectively inhibiting cobalt nucleation, depositing a barrier layer on the features.

12 . The method of claim 11 , wherein the barrier layer is selected from the group consisting of titanium, titanium nitride, tungsten, tungsten-containing materials, tungsten nitride, tantalum, tantalum nitride, ruthenium, and cobalt nitride.

13 . The method of claim 1 , wherein (b) and (c) are performed at a temperature less than about 400° C.

14 . The method of claim 1 , wherein the cobalt-containing precursor is selected from the group consisting of dicarbonyl cyclopentadienyl cobalt, cobalt carbonyl, various cobalt amidinate precursors, cobalt diazadienyl complexes, cobalt amidinate/guanidinate precursors, and combinations thereof.

15 . The method of claim 1 , wherein the surfaces of the features that are at or near the feature openings comprise the top about 10% to about 50% of the feature sidewalls.

16 . The method of claim 1 , wherein the features comprise re-entrant profiles.

17 . The method of claim 1 , wherein depositing cobalt in (c) comprises exposing the substrate to the cobalt-containing precursor and a reducing agent.

18 . The method of claim 1 , wherein the feature opening is less than about 6×nm and the feature aspect ratio is between about 5:1 and about 100:1.

19 . An apparatus for processing semiconductor substrates, the apparatus comprising:
one or more process chambers; one or more gas inlets into the process chambers and associated flow-control hardware; a remote plasma generator; and a controller having at least one processor and a memory, wherein
the at least one processor and the memory are communicatively connected with one another,
the at least one processor is at least operatively connected with the flow-control hardware and plasma generator, and
the memory stores computer-executable instructions for:
(a) introducing a cobalt-containing precursor and reducing agent to the chamber,
(b) introducing a nitrogen-based plasma to the chamber, the nitrogen-based plasma generated by flowing a nitrogen-containing gas to the remote plasma generator and igniting a plasma,
(c) repeating (a) and (b), and
(d) heating the substrate to a temperature between about 250° C. and about 500° C.,

wherein the substrates comprise features having re-entrant profiles.

20 . The apparatus of claim 19 , wherein the memory further stores computer-executable instructions for optionally repeating (c) and (d).

Assignees

• Lam Res Corp

Inventors

• Lai Chiukin Steven
• Na Jeong-Seok
• Tarafdar Raihan
• Humayun Raashina
• Danek Michal

Classifications

• H10W20/4437

  the principal metal being a transition metal · CPC title

• H10P14/6319

  Formation by plasma treatments, e.g. plasma oxidation of the substrate · CPC title

• H10P14/6316

  Formation by nitridation, e.g. nitridation of the substrate · CPC title

• H10P14/432

  using selective deposition · CPC title

• H10P14/43

  Chemical deposition, e.g. chemical vapour deposition [CVD] · CPC title