# US 10,373,828 B2 · Method of sidewall image transfer

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- Number: US 10,373,828 B2
- Document ID: US10373828B2
- Status: Granted
- Kind: B2
- Application number: 15/607,406
- Filed: 2017-05-26
- Published: 2017-11-30
- Granted: 2019-08-06
- Earliest claimed: 2016-05-29
- Assignees: Tokyo Electron Limited
- Applicants: Tokyo Electron Limited
- Inventors: Alok Ranjan; Sonam D. Sherpa
- Web page: https://patentgrep.com/patent/US10373828B2

## CPC

- H10P 76/4085: {characterised by the processes involved to create the masks}
- H10P 14/2905: {Silicon, silicon germanium or germanium}
- H10P 14/6309: {of silicon in uncombined form, i.e. pure silicon}
- H10P 50/242: {of Group IV materials}
- H10P 50/267: {using plasmas}
- H10P 50/268: {of silicon-containing layers}
- H10P 50/283: {by chemical means}
- H10P 14/6336: {in the presence of a plasma [PECVD]}
- H10P 14/6339: {deposition by cyclic CVD, e.g. ALD, ALE or pulsed CVD}
- H10P 14/69433: {the material being a silicon nitride not containing oxygen, e.g. SixNy or SixByNz}
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

According to one embodiment, a substrate processing method includes providing a substrate containing Si raised features, depositing a conformal film on the Si raised features, and performing a spacer etch process that removes horizontal portions of the conformal film while substantially leaving vertical portions of the conformal film to form sidewall spacers on the Si raised features, the performing including a) exposing the substrate to a plasma-excited first process gas consisting of H2 gas and optionally an inert gas, and b) exposing the substrate to a plasma-excited second process gas containing i) NF3, O2, H2, and Ar, ii) NF3, O2, and H2, iii) NF3 and O2, iv) NF3, O2, and Ar, v) NF3 and H2, or vi) NF3, H2, and Ar. The method further includes removing the Si raised features while maintaining the sidewall spacers on the substrate. The removing may be performed using steps a) and b).

## Claims

### Claim 1

A substrate processing method, the method comprising:
providing a substrate containing silicon (Si) raised features;
depositing a conformal film on the Si raised features;
performing a spacer etch process that removes horizontal portions of the conformal film while substantially leaving vertical portions of the conformal film to form sidewall spacers on the Si raised features, the performing including
a) exposing the substrate to a plasma-excited first process gas consisting of H2 gas and optionally an inert gas, and
b) exposing the substrate to a plasma-excited second process gas containing i) NF3, O2, H2, and Ar, ii) NF3, O2, and H2, iii) NF3 and O2, iv) NF3, O2, and Ar, v) NF3 and H2, or vi) NF3, H2, and Ar; and
removing the Si raised features while maintaining the sidewall spacers on the substrate, the removing including
c) exposing the substrate to a plasma-excited third process gas consisting of H2 gas and optionally an inert gas, and
d) exposing the substrate to a plasma-excited fourth process gas consisting of i) NF3, O2, H2, and Ar, ii) NF3, O2, and H2, iii) NF3 and O2, iv) NF3, O2, and Ar, v) NF3 and H2, or vi) NF3, H2, and Ar.

### Claim 2 (depends on 1)

The method of claim 1, wherein the first and third process gases consist of H2 and Ar.

### Claim 3 (depends on 1)

The method of claim 1, wherein the second and fourth process gases consist of NF3, O2, H2, and Ar.

### Claim 4 (depends on 1)

The method of claim 1, wherein the Si raised features consist of elemental Si.

### Claim 5 (depends on 4)

The method of claim 4, wherein the elemental Si includes polycrystalline Si (poly-Si) or amorphous Si (a-Si).

### Claim 6 (depends on 1)

The method of claim 1, wherein the conformal film includes SiN.

### Claim 7 (depends on 1)

The method of claim 1, wherein the plasma-excited process gases are formed using a capacitively coupled plasma source containing an upper plate electrode, and a lower plate electrode supporting the substrate.

### Claim 8 (depends on 1)

The method of claim 1, wherein the plasma-excited process gases are formed using a remote plasma source that creates a high radical to ion flux ratio.

### Claim 9 (depends on 1)

The method of claim 1, further repeating steps a) and b), and steps c) and d), at least once.

### Claim 10

A substrate processing method, the method comprising:
providing a substrate containing Si raised features;
depositing a conformal film on the Si raised features;
performing a plasma process that modifies horizontal portions of the conformal film while substantially leaving vertical portions of the conformal film unmodified, the performing including
a) exposing the substrate to a plasma-excited first process gas consisting of H2 gas and optionally an inert gas, and
b) exposing the substrate to a plasma-excited second process gas containing i) NF3, O2, H2, and Ar, ii) NF3, O2, and H2, iii) NF3 and O2, iv) NF3, O2, and Ar, v) NF3 and H2, or vi) NF3, H2, and Ar; and
removing the modified horizontal portions of the conformal film and the Si raised features, the removing including
c) exposing the substrate to a plasma-excited third process gas consisting of H2 gas and optionally an inert gas, and
d) exposing the substrate to a plasma-excited fourth process gas consisting of i) NF3, O2, H2, and Ar, ii) NF3, O2, and H2, iii) NF3 and O2, iv) NF3, O2, and Ar, v) NF3 and H2, or vi) NF3, H2, and Ar.

### Claim 11 (depends on 10)

The method of claim 10, wherein the first and third process gases consist of H2 and Ar.

### Claim 12 (depends on 10)

The method of claim 10, wherein the second and fourth process gases consist of NF3, O2, H2, and Ar.

### Claim 13 (depends on 10)

The method of claim 10, wherein the Si raised features include polycrystalline Si (poly-Si) or amorphous Si (a-Si).

### Claim 14 (depends on 10)

The method of claim 10, wherein the conformal film includes SiN.

### Claim 15 (depends on 10)

The method of claim 10, wherein the plasma-excited process gases are formed using a capacitively coupled plasma source containing an upper plate electrode, and a lower plate electrode supporting the substrate.

### Claim 16 (depends on 10)

The method of claim 10, wherein the plasma-excited process gases are formed using a remote plasma source that creates a high radical to ion flux ratio.

### Claim 17 (depends on 10)

The method of claim 10, further including repeating steps a) and b), and steps c) and d), at least once.

### Claim 18

A substrate processing method, the method comprising:
providing a substrate containing SiN sidewall spacers on Si raised features; and
removing the Si raised features while maintaining the SiN sidewall spacers on the substrate, the removing including
exposing the substrate to a first plasma-excited process gas consisting of H2 gas and optionally an inert gas, and
exposing the substrate to a second plasma-excited process gas consisting of i) NF3, O2, H2, and Ar, ii) NF3, O2, and H2, iii) NF3 and O2, iv) NF3, O2, and Ar, v) NF3 and H2, or vi) NF3, H2, and Ar.

### Claim 19 (depends on 18)

The method of claim 18, wherein the first process gas consists of H2 and Ar, and the second process gas consists of NF3, O2, H2, and Ar.

### Claim 20 (depends on 19)

The method of claim 19, further including repeating the exposing steps at least once.