# US 10,770,285 B2 · Silicon member and method of producing the same

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- Number: US 10,770,285 B2
- Document ID: US10770285B2
- Status: Granted
- Kind: B2
- Application number: 14/227,189
- Filed: 2014-03-27
- Published: 2014-10-02
- Granted: 2020-09-08
- Earliest claimed: 2013-03-28
- Assignees: Mitsubishi Materials Corporation
- Applicants: Mitsubishi Materials Corporation
- Inventors: Yoshinobu Nakada
- Web page: https://patentgrep.com/patent/US10770285B2

## CPC

- H10P 14/6903: {containing silicon}
- F27B 14/06: heated electrically, e.g. induction crucible furnaces with or without any other source of heat (F27B14/04 takes precedence)
- H10D 62/00: Semiconductor bodies, or regions thereof, of devices having potential barriers
- H10D 62/01: {Manufacture or treatment}
- H10D 62/40: Crystalline structures
- H10P 14/6304: {Formation by oxidation, e.g. oxidation of the substrate}
- H10P 14/6309: {of silicon in uncombined form, i.e. pure silicon}
- H10P 14/6316: {Formation by nitridation, e.g. nitridation of the substrate}
- H10P 14/69215: {the material being a silicon oxide, e.g. SiO2}
- H10P 14/69433: {the material being a silicon nitride not containing oxygen, e.g. SixNy or SixByNz}
- H10W 42/121: {protecting against mechanical damage (H10W76/00, H10W74/00 take precedence)}
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- F27B: FURNACES, KILNS, OVENS OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
- H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

A silicon member and a method of producing the silicon member are provided. Cracking is suppressed in the silicon member even if the silicon member is used in a condition where it is heated. The silicon member 10 includes a coating layer 11 that coats a surface of the silicon member 10, wherein the coating layer 11 is composed of a product of silicon formed by reaction of the silicon on the surface, and a thickness of the coating layer is 15 nm or more and 600 nm or less. It is preferable that the coating layer is a silicon oxide film or a silicon nitride film.

## Claims

### Claim 1

A method of producing a holding plate for a liquid crystal panel in deposition and heat treatment that is used in a condition where the holding plate is heated at a temperature ranged from 300°C. to 1100°C., the method comprising steps of:
excising a large-sized plate material made of a poly-crystalline silicon or a pseudosingle-crystalline silicon from a unidirectionally solidified columnar crystal ingot;
forming a coating layer composed of a product of silicon formed by reaction of the silicon on a surface of the large-sized plate material which has micro-cracks on the surface before forming the coating layer, wherein
the large-sized plate material has the dimension: width W being 500 mm to 1500 mm; length L being 500 mm to 1500 mm; and thickness H being 5 mm to 50 mm,
the step of forming the coating layer comprises the steps of:
forming a silicon oxide film on the surface of the large-sized plate material in a furnace by pyrogenic oxidation;
removing the silicon oxide film from the large-sized plate material using a buffered hydrofluoric acid solution; and
forming a silicon nitride film on the surface of the large-sized plate material as the coating layer while flowing ammonia into the furnace; wherein
a thickness of the coating layer, t10, is 15 nm or more and 50 nm or less, and after forming the coating layer,
the surface of the holding plate is free of scratches and micro-cracks,
a maximum load in four-point bending of the holding plate is between 188-265 MPa, and
a penetration depth, t11, of the silicon nitride film into silicon on the surface toward an internal side of the large-sized plate material satisfies a formula t11≥0.88×t10 based on densities and molecular weights of Si and Si3N4, t10 and t11 being measured with a spectroscopic ellipsometer.

### Claim 2

A method of producing a holding plate comprising steps of:
excising a large-sized plate material made of a poly-crystalline silicon or a pseudosingle-crystalline silicon from a unidirectionally solidified columnar crystal ingot;
forming a coating layer composed of a product of silicon formed by reaction of the silicon on a surface of the large-sized plate material which has micro-cracks on the surface before forming the coating layer, wherein
the large-sized plate material has the dimension: width W being 500 mm to 1500 mm; length L being 500 mm to 1500 mm; and thickness H being 5 mm to 50 mm,
the step of forming the coating layer comprises the steps of:
forming a silicon oxide film on the surface of the large-sized plate material in a furnace by pyrogenic oxidation;
removing the silicon oxide film from the large-sized plate material using a buffered hydrofluoric acid solution; and
forming a silicon nitride film on the surface of the large-sized plate material as the coating layer while flowing ammonia into the furnace.

### Claim 3 (depends on 2)

The method according to claim 2, wherein a thickness of the coating layer, t10, is 15 nm or more and 50 nm or less.

### Claim 4 (depends on 2)

The method according to claim 2, wherein after forming the coating layer, the surface of the holding plate is free of scratches and micro-cracks.

### Claim 5 (depends on 2)

The method according to claim 2, wherein after forming the coating layer, a maximum load in four-point bending of the holding plate is between 188-265 MPa.

### Claim 6 (depends on 3)

The method according to claim 3, wherein after forming the coating layer, a penetration depth, t11, of the silicon nitride film into silicon on the surface toward an internal side of the large-sized plate material satisfies a formula t11≥0.88×t10 based on densities and molecular weights of Si and Si3N4, t10 and t11 being measured with a spectroscopic ellipsometer.