# US 12,110,422 B2 · Polishing method and polishing composition

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

- Number: US 12,110,422 B2
- Document ID: US12110422B2
- Status: Granted
- Kind: B2
- Application number: 18/529,465
- Filed: 2023-12-05
- Published: 2024-03-28
- Granted: 2024-10-08
- Earliest claimed: 2021-02-04
- Assignees: Fujimi Incorporated
- Applicants: Fujimi Incorporated
- Inventors: Yuichiro Nakagai; Hiroyuki Oda; Yasuaki Ito; Shogaku Ide; Shinichiro Takami
- Web page: https://patentgrep.com/patent/US12110422B2

## CPC

- C09G 1/02: containing abrasives or grinding agents {(abrasives as such C09K3/14; polishing of semi-conductors H10P52/40)}
- C09K 3/1409: {Abrasive particles per se (preparation of diamond C01B32/25)}
- C09K 3/1463: {Aqueous liquid suspensions}
- H10P 90/129: {by polishing}
- C09G: POLISHING COMPOSITIONS (French polish C09F11/00); SKI WAXES
- C09K: MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

Provided are a polishing method and a polishing composition that are applied to polishing of silicon carbide and allows reduction of rise in pH of the polishing composition and increase in pad temperature during polishing Provided is a method of polishing an object to be polished having a surface formed of silicon carbide. The method includes steps of preparing a polishing composition, and supplying the polishing composition to the object to be polished and polishing the object to be polished. The polishing composition contains permanganate, a metal salt A, and water. The metal salt A is a salt of a metal cation having a pKa of less than 7.0 in form of a hydrated metal ion, and an anion.

## Claims

### Claim 1

A method of polishing an object to be polished, the method comprising:
preparing a polishing composition, and
supplying the polishing composition to the object to be polished, and polishing the object to be polished,
wherein during the polishing step, the polishing composition supplied to the object to be polished has an initial pH and the polishing composition flowing from the object to be polished has a rise in pH of less than 2.0 relative to the initial pH,
wherein the polishing composition comprises permanganate, a metal salt A, and water,
the metal salt A is a salt of a metal cation having a pKa of less than 7.0 in form of a hydrated metal ion, and an anion,
the concentration of the metal salt A is 8 mM or more, and
the object to be polished has a surface formed of silicon carbide.

### Claim 2 (depends on 1)

The polishing method according to claim 1, wherein the pH of the polishing composition supplied to the object to be polished is 5.0 or less.

### Claim 3 (depends on 1)

The polishing method according to claim 1, wherein the polishing composition comprises an abrasive.

### Claim 4 (depends on 3)

The polishing method according to claim 3, wherein a ratio of the concentration of permanganate to the square root of the content of the abrasive is preferably 300 or more.

### Claim 5 (depends on 4)

The polishing method according to claim 4, wherein a ratio of the concentration of permanganate to the square root of the content of the abrasive is preferably 200 or more.

### Claim 6 (depends on 3)

The polishing method according to claim 3, wherein the abrasive is formed of alumina particles.

### Claim 7 (depends on 3)

The polishing method according to claim 3, wherein the abrasive is formed of silica particles.

### Claim 8 (depends on 1)

The polishing method according to claim 1, wherein in the metal salt A, the metal cation is a cation comprising a metal belonging to groups 3 to 16 in the periodic table.

### Claim 9 (depends on 1)

The polishing method according to claim 1, wherein the metal salt A is a salt of a metal cation having a pKa of less than 6.0 in form of a hydrated metal ion, and an anion.

### Claim 10 (depends on 1)

The polishing method according to claim 1, wherein the metal cation of the metal salt A is selected from a group consisting of Al3+, Cr3+, In3+, Ga3+, Fe3+, Hf4+, Zr4+, Ce4+, and Ti4+.

### Claim 11 (depends on 1)

The polishing method according to claim 1, wherein the anion of the metal salt A is selected from a group consisting of nitrate ion (NO3−), a chloride ion (Cl−), a sulfate ion (SO42−), and an acetate ion (CH3COO−).

### Claim 12 (depends on 1)

The polishing method according to claim 1, wherein the metal salt A can buffer pH to 2.5 to 5.5.

### Claim 13 (depends on 1)

The polishing method according to claim 1, wherein a ratio of the concentration of metal salt A to the concentration of permanganate in the polishing composition is 0.0002 or more.

### Claim 14 (depends on 1)

The polishing method according to claim 1, wherein the metal cation of the metal salt A is selected from a group consisting of In3+, Ga3+, Hf4+ and Ti4+.

### Claim 15 (depends on 1)

A polishing composition used in the polishing method of claim 1 for polishing an object to be polished, the polishing composition comprising:
permanganate, a metal salt A, and water,
wherein the metal salt A is a salt of a metal cation having a pKa of less than 7.0 in form of a hydrated metal ion, and an anion,
the concentration of the metal salt A is 8 mM or more, and
the object to be polished has a surface formed of silicon carbide.