# US 10,319,582 B2 · Methods and apparatus for depositing silicon oxide on metal layers

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- Number: US 10,319,582 B2
- Document ID: US10319582B2
- Status: Granted
- Kind: B2
- Application number: 15/499,318
- Filed: 2017-04-27
- Published: 2018-11-01
- Granted: 2019-06-11
- Earliest claimed: 2017-04-27
- Assignees: Lam Research Corporation
- Applicants: Lam Research Corporation
- Inventors: Bhadri N. Varadarajan; Zhe Gui; Bo Gong; Andrew John McKerrow
- Web page: https://patentgrep.com/patent/US10319582B2

## CPC

- H10P 14/6905: {being a silicon carbide or silicon carbonitride and not containing oxygen, e.g. SiC or SiC:H}
- H10P 14/6339: {deposition by cyclic CVD, e.g. ALD, ALE or pulsed CVD}
- H10P 14/6532: {by exposure to a plasma}
- H10P 14/6681: {the precursor containing a compound comprising Si}
- H10P 14/6687: {the compound comprising silicon and nitrogen}
- H10P 14/69215: {the material being a silicon oxide, e.g. SiO2}
- H10P 14/6922: {the material containing Si, O and at least one of H, N, C, F or other non-metal elements, e.g. SiOC, SiOC:H or SiONC}
- H10P 70/27: {during, before or after processing of conductive materials, e.g. polysilicon or amorphous silicon layers}
- H10P 76/2041: {Photolithographic processes}
- H10W 20/01: {Manufacture or treatment}
- H10W 20/077: {on sidewalls or on top surfaces of conductors (H10W20/076 takes precedence)}
- H10N 50/01: Manufacture or treatment
- 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
- H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR

## Abstract

Thin layer of silicon oxide is deposited on a substrate having an exposed layer of metal (e.g., W, Cu, Ti, Co, Ta) without causing substantial oxidation of the metal. The method involves: (a) contacting the substrate having an exposed metal layer with a silicon-containing precursor and adsorbing the precursor on the substrate; (b) removing the unadsorbed precursor from a process chamber; and (c) contacting the adsorbed precursor with a plasma formed in a process gas comprising an oxygen source (e.g., O2, CO2, N2O, O3) and H2, to form silicon oxide from the silicon-containing precursor while suppressing metal oxidation. These steps can be repeated until a silicon oxide film of a desired thickness is formed. In some embodiments, the silicon oxide film is used to improve nucleation of subsequently deposited silicon carbide.

## Claims

### Claim 1

A method for processing a semiconductor substrate, the method comprising:
(a) providing a semiconductor substrate comprising an exposed metal layer; and
(b) forming a silicon oxide layer over and in contact with the metal layer, wherein forming the silicon oxide layer comprises reacting a silicon-containing precursor adsorbed to the metal layer with a plasma formed in a process gas comprising H2 and an oxygen source, wherein the composition of the process gas is configured for suppressing oxidation of the metal layer, and
(c) contacting the semiconductor substrate having an exposed silicon oxide layer after (b) with a reducing plasma to reduce residual metal oxide underlying the silicon oxide layer to metal.

### Claim 2 (depends on 1)

The method of claim 1, wherein the volume ratio of H2 to the oxygen source in the process gas is at least 4:1.

### Claim 3 (depends on 1)

The method of claim 1, wherein the oxygen source is O2, and wherein the volume ratio of H2 to O2 in the process gas is at least 9:1.

### Claim 4 (depends on 1)

The method of claim 1, wherein the oxygen source is O2, and wherein the volume ratio of H2 to O2 in the process gas is at least 10:1.

### Claim 5 (depends on 1)

The method of claim 1, wherein the oxygen source is O2, and wherein the process gas consists essentially of H2 at a concentration of between about 2-10%, O2 at a concentration of less than 1%, and an inert gas.

### Claim 6 (depends on 1)

The method of claim 1, wherein the oxygen source is O2, and wherein the process gas consists essentially of H2 at a concentration of greater than about 95% and O2 at a concentration of less than about 5%.

### Claim 7 (depends on 1)

The method of claim 1, wherein the oxygen source is selected from the group consisting of O2, O3, CO2 and N2O.

### Claim 8 (depends on 1)

The method of claim 1, wherein the oxygen source is O2.

### Claim 9 (depends on 1)

The method of claim 1, wherein the metal is selected from the group consisting of W, Cu, Co, Ti, and Ta.

### Claim 10 (depends on 1)

The method of claim 1, wherein the metal is W.

### Claim 11 (depends on 1)

The method of claim 1, wherein (b) comprises:
(i) contacting the semiconductor substrate with the silicon-containing precursor and adsorbing the silicon-containing precursor on the layer of metal;
(ii) removing the unadsorbed silicon-containing precursor by purging and/or evacuating a process chamber housing the semiconductor substrate;
(iii) contacting the semiconductor substrate with the plasma formed in the process gas comprising H2 and the oxygen source and forming silicon oxide from the adsorbed silicon-containing precursor;
(iv) purging and/or evacuating the process chamber after (iii); and
(v) repeating steps (i) (iv).

### Claim 12 (depends on 1)

The method of claim 1, further comprising pre-cleaning the exposed metal layer to remove metal oxide from the exposed metal layer prior to (b).

### Claim 13 (depends on 1)

The method of claim 1, wherein the silicon oxide is formed in (b) to a thickness of less than about 10 Å.

### Claim 14 (depends on 1)

The method of claim 1, wherein the silicon oxide is formed in (b) to a thickness of about 5 Å.

### Claim 15 (depends on 1)

The method of claim 1, further comprising:
applying photoresist to the semiconductor substrate;
exposing the photoresist to light;
patterning the photoresist and transferring the pattern to the semiconductor substrate; and
selectively removing the photoresist from the semiconductor substrate.

### Claim 16 (depends on 1)

The method of claim 1, wherein (b) further comprises reducing a metal oxide formed on the metal layer to metal.

### Claim 17 (depends on 1)

The method of claim 1, wherein the semiconductor substrate provided in (a) comprises a plurality of recessed features and further comprises an exposed dielectric layer, and wherein the silicon oxide is formed both on the exposed metal layer and the exposed dielectric layer.

### Claim 18 (depends on 17)

The method of claim 17, further comprising depositing a silicon carbide layer onto the silicon oxide layer.