# US 11,908,938 B2 · Substrate processing liquid for etching a metal layer, substrate processing method and substrate processing apparatus

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

- Number: US 11,908,938 B2
- Document ID: US11908938B2
- Status: Granted
- Kind: B2
- Application number: 17/191,841
- Filed: 2021-03-04
- Published: 2021-09-16
- Granted: 2024-02-20
- Earliest claimed: 2020-03-11
- Assignees: SCREEN Holdings Co., Ltd.
- Applicants: SCREEN Holdings Co., Ltd.
- Inventors: Dai Ueda; Yosuke Hanawa
- Web page: https://patentgrep.com/patent/US11908938B2

## CPC

- H10D 30/62: Fin field-effect transistors [FinFET]
- C23F 1/26: for etching refractory metals
- C23F 1/32: Alkaline compositions (C23F1/42 takes precedence)
- C23F 1/38: for etching refractory metals
- H10D 30/024: {of fin field-effect transistors [FinFET]}
- H10P 50/642: {Chemical etching}
- H10P 50/667: {by liquid etching only}
- H10P 72/0406: {for cleaning followed by drying, rinsing, stripping, blasting or the like}
- H10P 72/0424: {using mainly spraying means, e.g. nozzles}
- H10P 72/0454: {surrounding a central transfer chamber}
- H10P 72/0458: {vertical arrangement}
- H10P 72/3302: {Mechanical parts of transfer devices}
- H10P 72/7612: {characterised by lifting arrangements, e.g. lift pins}
- H10D 64/01318: {the conductor comprising a layer of alloy material, compound material or organic material contacting the insulator, e.g. TiN (comprising a layer of alloys of Si, Ge or C H10D64/01314)}
- H10D 64/667: {the conductor comprising a layer of alloy material, compound material or organic material contacting the insulator, e.g. TiN workfunction layers (having lateral variation H10D64/671)}
- H10D 84/0135: {Manufacturing their gate conductors}
- H10D 84/038: {using silicon technology, e.g. SiGe}
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- C23F: NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE (working metal by laser beams B23K26/00; desurfacing by applying flames B23K7/00; working of metal by electro-erosion B23H; producing decorative effects by removing surface material, e.g. by engraving, by etching, B44C1/22; electrolytic etching or polishing C25F); INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

A substrate processing liquid is used to etch a substrate in which at least either a bottom wall or a side wall forming a trench structure is an etched layer made of metal or a metal compound. The substrate processing liquid includes a chemical liquid containing H2O2 molecules or HO2− functioning as an etchant for etching the metal, and a complex forming agent containing NH4+ and forming a complex with ions of the metal and is adjusted to a pH of 5 or more.

## Claims

### Claim 1

A substrate processing liquid for removing an etched layer by being supplied to a substrate having a trench structure in which a narrow space is formed by an opening having a narrow width, a bottom wall facing the opening and one or more side walls extending toward the opening and at least either the bottom wall or the side wall is formed by the etched layer made of metal or a metal compound, the liquid comprising:
a chemical liquid containing H2O2 molecules or HO2+ functioning as an etchant for etching the metal; and
a complex forming agent containing NH4+ and forming a complex with ions of the metal, wherein
a pH is adjusted to a value that is equal to or more than 8 but no more than 9.

### Claim 2 (depends on 1)

The substrate processing liquid according to claim 1, wherein:
the substrate is formed with a high-k metal gate layer covering over two adjacent fins standing from a surface of the substrate while being spaced apart to form a gate of a FinFET, and
a surface layer of the high-k metal gate layer is etched and removed as the etched layer.

### Claim 3 (depends on 2)

The substrate processing liquid according to claim 2, wherein:
the metal includes at least one kind of titanium and tantalum.

### Claim 4 (depends on 1)

The substrate processing liquid according to claim 1, wherein:
the chemical liquid is a hydrogen peroxide aqueous solution.

### Claim 5 (depends on 1)

The substrate processing liquid according to claim 1, wherein:
the complex forming agent is an ammonium salt expressed by a general formula (1):
(NH4+)nXn− (1),
where Xn− denotes n-valent anions and n is 1 or 2.

### Claim 6 (depends on 1)

The substrate processing liquid according to claim 1, further comprising:
a pH adjuster for adjusting the pH, wherein:
the pH adjuster contains at least one kind of ammonium hydroxide, sodium hydroxide and potassium hydroxide.

### Claim 7 (depends on 1)

The substrate processing liquid according to claim 1, wherein:
an ion concentration of the complex forming agent is 1 m mol/L or more and 10 m mol/L or less.

### Claim 8 (depends on 1)

The substrate processing liquid according to claim 1, wherein:
the complex forming agent is an alkyl ammonium salt expressed by a general formula (1):
(NR4+)nXn− (1),
where Xn− denotes n-valent anions and n is 1 or 2.

### Claim 9

A substrate processing method, comprising:
removing an etched layer by supplying a substrate processing liquid to a substrate having a trench structure in which a narrow space is formed by an opening having a narrow width, a bottom wall facing the opening and one or more side walls extending toward the opening and at least either the bottom wall or the side wall is formed by the etched layer made of metal or a metal compound; and
stopping the removal of the etched layer by removing the substrate processing liquid from the substrate, wherein:
the substrate processing liquid includes a chemical liquid containing H2O2 molecules or HO2− functioning as an etchant for etching the metal and a complex forming agent containing NH4+ and forming a complex with ions of the metal; and
the substrate processing liquid is adjusted to a pH value that is equal to or more than 8 but no more than 9.

### Claim 10 (depends on 9)

The substrate processing method according to claim 9, wherein:
an ion concentration of the complex forming agent of the substrate processing liquid is 1 m mol/L or more and 10 m mol/L or less.

### Claim 11

A substrate processing apparatus, comprising:
a substrate holder that holds a substrate having a trench structure in which a narrow space is formed by an opening having a narrow width, a bottom wall facing the opening and one or more side walls extending toward the opening and at least either the bottom wall or the side wall is formed by an etched layer made of metal or a metal compound; and
a processing liquid supplier that supplies a substrate processing liquid to the substrate held by the substrate holder, wherein:
the substrate processing liquid includes a chemical liquid containing H2O2 molecules or HO2− functioning as an etchant for etching the metal and a complex forming agent containing NH4+ and forming a complex with ions of the metal; and
the substrate processing liquid is adjusted to a pH value that is equal to or more than 8 but no more than 9.

### Claim 12 (depends on 11)

The substrate processing apparatus according to claim 11, wherein:
an ion concentration of the complex forming agent of the substrate processing liquid is 1 m mol/L or more and 10 m mol/L or less.

### Claim 13 (depends on 11)

The substrate processing apparatus according to claim 11, wherein:
the substrate processing liquid is adjusted to a pH of 8 or more, and
an ion concentration of the complex forming agent of the substrate processing liquid is 1 m mol/L or more and 2 m mol/L or less.