# US 2020/0286743 A1 · Atomic layer etch of tungsten for enhanced tungsten deposition fill

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- Number: US 2020/0286743 A1
- Document ID: US20200286743A1
- Status: Published application
- Kind: A1
- Application number: 15/929,854
- Filed: 2020-05-26
- Published: 2020-09-10
- Earliest claimed: 2015-08-07
- Assignees: Lam Research Corporation
- Applicants: Lam Research Corporation
- Inventors: Chiukin Steven Lai; Keren Jacobs Kanarik; Samantha Tan; Anand Chandrashekar; Teh-Tien Su; Wenbing Yang; Michael Wood; Michal Danek
- Web page: https://patentgrep.com/patent/US20200286743A1

## CPC

- H10P 50/267: {using plasmas}
- H10W 20/056: {by filling conductive material into holes, grooves or trenches}
- H10W 20/0595: {by using multiple deposition steps separated by etching steps}
- H10P 14/43: Chemical deposition, e.g. chemical vapour deposition [CVD]
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## 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.

## Claims

### Claim 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.

### Claim 2 (depends on 1)

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

### Claim 3 (depends on 1)

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

### Claim 4 (depends on 1)

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

### Claim 5 (depends on 4)

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

### Claim 6 (depends on 1)

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

### Claim 7 (depends on 1)

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

### Claim 8 (depends on 1)

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

### Claim 9 (depends on 1)

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

### Claim 10 (depends on 8)

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

### Claim 11 (depends on 1)

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

### Claim 12 (depends on 1)

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

### Claim 13 (depends on 1)

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

### Claim 14 (depends on 1)

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

### Claim 15 (depends on 1)

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.

### Claim 16 (depends on 11)

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

### Claim 17 (depends on 4)

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

### Claim 18 (depends on 1)

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

### Claim 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.

### Claim 20 (depends on 19)

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

### Claim 21 (depends on 19)

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

### Claim 22 (depends on 19)

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

### Claim 23 (depends on 19)

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

### Claim 24 (depends on 19)

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

### Claim 25 (depends on 19)

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

### Claim 26 (depends on 19)

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

### Claim 27 (depends on 19)

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

### Claim 28 (depends on 19)

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.

### Claim 29 (depends on 19)

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

### Claim 30 (depends on 19)

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

### Claim 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.

### Claim 32 (depends on 31)

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

### Claim 33 (depends on 31)

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).

### Claim 34 (depends on 31)

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

### Claim 35 (depends on 31)

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