# US 12,009,211 B2 · Method for highly anisotropic etching of titanium oxide spacer using selective top-deposition

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 12,009,211 B2
- Document ID: US12009211B2
- Status: Granted
- Kind: B2
- Application number: 17/525,860
- Filed: 2021-11-12
- Published: 2023-05-18
- Granted: 2024-06-11
- Earliest claimed: 2021-11-12
- Assignees: Tokyo Electron Limited
- Applicants: Tokyo Electron Limited
- Inventors: Ya-Ming Chen; Katie Lutker-Lee; Eric Chih-Fang Liu; Angelique Raley; Stephanie Oyola-Reynoso; Shihsheng Chang
- Web page: https://patentgrep.com/patent/US12009211B2

## CPC

- H01J 37/321: {the radio frequency energy being inductively coupled to the plasma}
- H10P 76/4085: {characterised by the processes involved to create the masks}
- H10P 50/285: {of materials not containing Si, e.g. PZT or Al2O3}
- H01J 37/3211: {Antennas, e.g. particular shapes of coils}
- H01J 2237/3341: Reactive etching
- H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H)
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

Methods are provided herein for forming spacers on a patterned substrate. A self-aligned multiple patterning (SAMP) process is utilized for patterning structures, spacers formed adjacent mandrels, on a substrate. In one embodiment, a novel approach of etching titanium oxide (TiO2) spacers is provided. Highly anisotropic etching of the spacer along with a selective top deposition is provided. In one embodiment, an inductively coupled plasma (ICP) etch tool is utilized. The etching process may be achieved as a one-step etching process. More particularly, a protective layer may be selectively formed on the top of the spacer to protect the mandrel as well as minimize the difference of the etching rates of the spacer top and the spacer bottom. In one embodiment, the techniques may be utilized to etch TiO2 spacers formed along amorphous silicon mandrels using an ICP etch tool utilizing a one-step etch process.

## Claims

### Claim 1

A method of forming spacers on a substrate for use in a self-aligned multiple patterning process (SAMP), the method comprising:
forming a plurality of structures on the substrate, the plurality of structures comprising at least mandrels, the mandrels being used as part of the SAMP process;
forming a spacer layer over the mandrels;
providing an inductively coupled plasma apparatus;
generating a one-step plasma in the inductively coupled plasma apparatus, the one-step plasma formed in a presence of a reactive etching gas and a passivating agent gas;
utilizing the one-step plasma to etch the spacer layer with a reactive etching species with to form the spacers on sidewalls of the mandrels; and
utilizing the one-step plasma to forming a protective layer on tops of the mandrels, the protective layer lessening the etch of the mandrels when the spacers are formed with the one-step plasma.

### Claim 2 (depends on 1)

The method of claim 1, wherein the spacer layer comprises titanium oxide.

### Claim 3 (depends on 1)

The method of claim 1, wherein the mandrels comprise amorphous silicon.

### Claim 4 (depends on 3)

The method of claim 3, wherein the spacer layer comprises titanium oxide.

### Claim 5 (depends on 4)

The method of claim 4, wherein the reactive etching gas comprises chlorine.

### Claim 6 (depends on 4)

The method of claim 4, wherein the passivating agent gas comprises methane.

### Claim 7 (depends on 6)

The method of claim 6, wherein the reactive etching gas comprises chlorine.

### Claim 8 (depends on 7)

The method of claim 7, wherein the one-step plasma is formed in a presence of carbon tetrafluoride (CF4) and/or nitrogen trifluoride.

### Claim 9

The method of 1, wherein the mandrels have a pitch of 40 nm or less.

### Claim 10

A method of forming titanium oxide spacers on a substrate, the method comprising:
forming a plurality of structures on the substrate, the plurality of structures comprising at least mandrels, the mandrels being formed to have a pitch of 40 nm or less;
forming a titanium oxide spacer layer over the mandrels;
providing an inductively coupled plasma apparatus;
generating a plasma in the inductively coupled plasma apparatus, the plasma formed in a presence of a reactive etching gas and a passivating agent gas;
utilizing the plasma to etch the titanium oxide spacer layer with a reactive etching species with to form the titanium oxide spacers on sidewalls of the mandrels; and
utilizing the plasma to forming a protective layer on tops of the mandrels, the protective layer providing at least some protection to the mandrels while the titanium oxide spacer layer is being etched to form the spacers.

### Claim 11 (depends on 10)

The method of claim 10, wherein the mandrels comprise amorphous silicon.

### Claim 12 (depends on 11)

The method of claim 11, wherein the reactive etching gas comprises chlorine.

### Claim 13 (depends on 11)

The method of claim 11, wherein the passivating agent gas comprises methane.

### Claim 14 (depends on 13)

The method of claim 13, wherein the reactive etching gas comprises chlorine.

### Claim 15 (depends on 10)

The method of claim 10, wherein the reactive etching gas comprises chlorine.

### Claim 16 (depends on 10)

The method of claim 10, wherein the passivating agent gas comprises methane.

### Claim 17 (depends on 16)

The method of claim 16, wherein the reactive etching gas comprises chlorine.

### Claim 18 (depends on 17)

The method of claim 17, wherein the plasma is formed in a presence of carbon tetrafluoride (CF4) and/or nitrogen trifluoride.

### Claim 19 (depends on 10)

The method of claim 10, wherein the mandrels are utilized as part of a self-aligned multiple patterning process.

### Claim 20 (depends on 19)

The method of claim 19, wherein the mandrels comprise amorphous silicon.