# US 11,306,248 B2 · Silicon etching solution, silicon etching method, and method of producing silicon fin structure

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- Number: US 11,306,248 B2
- Document ID: US11306248B2
- Status: Granted
- Kind: B2
- Application number: 16/905,163
- Filed: 2020-06-18
- Published: 2020-12-31
- Granted: 2022-04-19
- Earliest claimed: 2019-06-28
- Assignees: Tokyo Ohka Kogyo Co., Ltd.
- Applicants: Tokyo Ohka Kogyo Co., Ltd.
- Inventors: Ming-Yen Chung; Masaru Takahama
- Web page: https://patentgrep.com/patent/US11306248B2

## CPC

- C09K 13/00: Etching, surface-brightening or pickling compositions (for glass C03C15/00, {C03C25/66; for mortars, concrete, artificial or natural stone or ceramics C04B41/5338}; for metallic material C23F, C23G1/00, C25F1/00; {for semi-conductors H10P52/40})
- H10P 50/642: {Chemical etching}
- H10P 50/644: {Anisotropic liquid etching (H10P50/61 takes precedence)}
- H10P 90/126: {by chemical etching}
- 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

A silicon etching solution including a component which is a quaternary ammonium hydroxide represented by Formula (A-1), and a component which is a nonionic surfactant, in which an HLB value of the quaternary ammonium hydroxide is in a range of 12 to 15; in Formula (A-1), R1 to R4 each independently represent a monovalent hydrocarbon group, and the total number of carbon atoms contained in R1 to R4 is 10 or greater.

## Claims

### Claim 1

A silicon etching solution comprising:
a component (A) which is a quaternary ammonium hydroxide represented by Formula (A-1); and
a component (C) which is a nonionic surfactant,
wherein an HLB value of the component (C) is in a range of 12 to 15,
wherein the component (C) is a compound represented by Formula (C-1-1):
wherein R1 to R4 each independently represents a monovalent hydrocarbon group, and the total number of carbon atoms contained in R1 to R4 is 10 or greater
wherein X01 represents an integer of 7 to 13.

### Claim 2 (depends on 1)

The silicon etching solution according to claim 1, wherein the HLB value of the component (C) is in a range of 12.5 to 14.

### Claim 3 (depends on 1)

The silicon etching solution according to claim 1, wherein the component (A) is one or more compounds selected from the group consisting of tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, benzyltriethylammonium hydroxide, and hexadecyltrimethylammonium hydroxide.

### Claim 4 (depends on 1)

A silicon etching method comprising performing an etching treatment on a silicon substrate using the silicon etching solution according to claim 1.

### Claim 5 (depends on 1)

A method of producing a silicon fin structure, comprising producing a silicon fin structure using the silicon etching solution according to claim 1.