Atomic layer etch of tungsten for enhanced tungsten deposition fill

Patent metadata

Field	Value
Publication number	US-2020286743-A1
Application number	US-202015929854-A
Country	US
Kind code	A1
Filing date	May 26, 2020
Priority date	Aug 7, 2015
Publication date	Sep 10, 2020
Grant date	—

Abstract

Methods of depositing tungsten into high aspect ratio features using a dep-etch-dep process integrating various deposition techniques with alternating pulses of surface modification and removal during etch are provided herein.

First claim

What is claimed is:

1 . A method of filling features on a substrate, the method comprising:
(a) depositing a first amount of a metal in a feature; and (b) directionally etching the metal at or near an opening of the feature relative to an interior region of the feature by
(i) modifying the surface of the deposited metal by exposing the metal to a halogen-containing gas; and
(ii) exposing the modified surface to an activation gas to selectively etch the metal.

2 . The method of claim 1 , wherein the metal contains one of titanium, tantalum, nickel, cobalt, or molybdenum.

3 . The method of claim 1 , wherein the metal contains tungsten.

4 . The method of claim 1 , further comprising applying a bias during at least one of (i) and (ii).

5 . The method of claim 4 , wherein the bias power is less than a threshold bias power.

6 . The method of claim 1 , wherein (b) comprises a self-limiting reaction.

7 . The method of claim 1 , wherein the substrate comprises features having different size openings.

8 . The method of claim 1 , wherein (a) and (b) are performed without breaking vacuum.

9 . The method of claim 1 , wherein (a) and (b) are performed in the same chamber.

10 . The method of claim 8 , wherein (a) and (b) are performed in different chambers of the same tool.

11 . The method of claim 1 , further comprising igniting a plasma during at least one of (i) and (ii).

12 . The method of claim 1 , wherein the feature has an aspect ratio of at least 3:1.

13 . The method of claim 1 , wherein the opening is less than 20 nm wide.

14 . The method of claim 1 , further comprising repeating (a) and (b).

15 . The method of claim 1 , wherein the halogen-containing gas is selected from the group consisting of chlorine, bromine, iodine, sulfur hexafluoride, silicon tetrafluoride, boron trichloride, and combinations thereof.

16 . The method of claim 11 , wherein the plasma power is between about 0 W and about 1000 W.

17 . The method of claim 4 , wherein the bias power is less than about 80 Vb.

18 . The method of claim 1 , wherein the activation gas is selected from a group consisting of neon, krypton, and argon.

19 . A method comprising:
(a) partially filling a feature with tungsten; (b) directionally etching tungsten at or near the opening of the feature by exposing the substrate to alternating pulses of a halogen-containing gas and an activation gas; and (c) filling the feature with tungsten.

20 . The method of claim 19 , wherein a bias is applied during (b).

21 . The method of claim 19 , wherein a bias is applied during (b) at a threshold bias power.

22 . The method of claim 19 , wherein (a) and (b) are performed without breaking vacuum.

23 . The method of claim 19 , wherein (a) and (b) are performed in the same chamber.

24 . The method of claim 19 , further comprising repeating (a) and (b).

25 . The method of claim 19 , wherein filling the feature comprises repeating (a) and (b).

26 . The method of claim 19 , wherein the tungsten is deposited by CVD.

27 . The method of claim 19 , wherein the tungsten is deposited by ALD.

28 . The method of claim 19 , wherein the tungsten is deposited by exposing the substrate to alternating pulses of a tungsten-containing precursor and a reducing agent.

29 . The method of claim 19 , wherein the tungsten is deposited using a chlorine-containing tungsten precursor.

30 . The method of claim 19 , wherein the tungsten is fluorine-free tungsten.

31 . An apparatus for processing semiconductor substrates, the apparatus comprising:
a process chamber comprising a showerhead and a substrate support, a 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
the memory stores machine-readable instructions for:
(i) introducing a tungsten-containing precursor and a reducing agent to the chamber to deposit tungsten on a substrate;
(ii) introducing a halogen-containing gas to modify the surface of the tungsten; and
(iii) introducing an activation gas and igniting a plasma to etch at least part of the modified surface of tungsten.

32 . The apparatus of claim 31 , wherein the memory further stores machine-readable instructions for igniting a plasma during (ii).

33 . The apparatus of claim 31 , wherein the substrate support comprises a bias, and the memory further stores machine-readable instructions for setting the bias power less than about 80 Vb during (iii).

34 . The apparatus of claim 31 , wherein the memory further stores machine-readable instructions for repeating (ii) and (iii) in cycles.

35 . The apparatus of claim 31 , wherein the memory further stores machine-readable instructions for after performing (ii) and (iii), repeating (i).

Assignees

• Lam Res Corp

Inventors

• Lai Chiukin Steven
• Kanarik Keren Jacobs
• Tan Samantha
• Chandrashekar Anand
• Su Teh-Tien
• Yang Wenbing
• Wood Michael
• Danek Michal

Classifications

• H10W20/0595

  by using multiple deposition steps separated by etching steps · CPC title

• H10P14/43

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

• H10W20/056 Primary

  by filling conductive material into holes, grooves or trenches · CPC title

• H10P50/267 Primary

  using plasmas · CPC title

• H10D64/01342

  by deposition, e.g. evaporation, ALD or laser deposition (H10D64/01344 takes precedence) · CPC title