Silicon member and method of producing the same

Patent metadata

Field	Value
Publication number	US-10770285-B2
Application number	US-201414227189-A
Country	US
Kind code	B2
Filing date	Mar 27, 2014
Priority date	Mar 28, 2013
Publication date	Sep 8, 2020
Grant date	Sep 8, 2020

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.

First claim

What is claimed is:

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, t 10 , 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, t 11 , of the silicon nitride film into silicon on the surface toward an internal side of the large-sized plate material satisfies a formula t 11 ≥0.88×t 10 based on densities and molecular weights of Si and Si 3 N 4 , t 10 and t 11 being measured with a spectroscopic ellipsometer.

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.

3. The method according to claim 2 , wherein a thickness of the coating layer, t 10 , is 15 nm or more and 50 nm or less.

4. 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.

5. 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.

6. The method according to claim 3 , wherein after forming the coating layer, a penetration depth, t 11 , of the silicon nitride film into silicon on the surface toward an internal side of the large-sized plate material satisfies a formula t 11 ≥0.88×t 10 based on densities and molecular weights of Si and Si 3 N 4 , t 10 and t 11 being measured with a spectroscopic ellipsometer.

Assignees

• Mitsubishi Materials Corp

Inventors

• Nakada Yoshinobu

Classifications

• H10P14/69433

  the material being a silicon nitride not containing oxygen, e.g. SixNy or SixByNz · CPC title

• H10P14/69215

  the material being a silicon oxide, e.g. SiO2 · CPC title

• H10P14/6316

  Formation by nitridation, e.g. nitridation of the substrate · CPC title

• H10P14/6309

  of silicon in uncombined form, i.e. pure silicon · CPC title

• H10P14/6304

  Formation by oxidation, e.g. oxidation of the substrate · CPC title