Polysilicon fracture object and production method therefor

Patent metadata

Field	Value
Publication number	US-12404451-B2
Application number	US-202117925852-A
Country	US
Kind code	B2
Filing date	May 20, 2021
Priority date	Jun 9, 2020
Publication date	Sep 2, 2025
Grant date	Sep 2, 2025

Abstract

A polysilicon fractured product includes fractured pieces including a ridge portion generated by fracturing a polysilicon rod. An average radius of curvature (r) of the fractured pieces is 50 μm or more at a tip end of a ridge portion having an angle of 70° or less. The polysilicon fractured product is obtained by a method including fracturing a polysilicon rod to obtain fractured pieces, and etching at an etching speed of 2.5 μm/min or less to achieve an etching depth of 5 μm or more by immersing the fractured pieces obtained in the fracturing in an etching solution.

First claim

The invention claimed is:

1. A polysilicon fractured product comprising:
fractured polysilicon pieces having a ridge portion generated by fracturing a polysilicon rod,
wherein an average radius of curvature (r) at a tip end of a ridge portion having an angle of 70° or less of the fractured pieces is 60 μm or more, and
a ratio of ridge portions having a radius of curvature of 30 μm or less is 20% or less with respect to all measured ridge portions present in the fractured polysilicon pieces.

2. The polysilicon fractured product according to claim 1 , wherein an average particle diameter is 20 mm to 100 mm.

3. The polysilicon fractured product according to claim 1 , wherein the pieces have an average particle diameter of 30 mm to 80 mm.

4. The polysilicon fractured product according to claim 1 , wherein a fractured piece is in the shape of an irregular polyhedron having a surface that includes the ridge portion.

5. A polysilicon fractured product according to claim 1 , wherein the ridge portion comprises a side formed by a fractured surface (3) of a polysilicon rod and a side formed by a polysilicon rod surface (4).

6. A polysilicon fractured product according to claim 1 , wherein the ridge portion is a vertex formed by a side formed by a fractured surface ( 3 ) of a polysilicon rod and a side formed by a polysilicon rod surface ( 4 ) and the angle is formed by the two sides.

7. A polysilicon fractured product according to claim 1 , wherein an average radius of curvature at a tip end of a ridge portion having an angle of 22° to 70° of the fractured pieces is 60 μm to 115 μm.

8. A polysilicon package filled with the polysilicon fractured product according to claim 1 in a resin bag.

9. The polysilicon fractured product according to claim 1 , wherein a ratio of a ridge portions having a radius of curvature of 30 μm or less is 8% or less, with respect to all measured ridge portions present in the fractured polysilicon pieces.

10. The polysilicon fractured product according to claim 1 , wherein a content of polysilicon fine powder is 200 ppmw or less for a fine powder of 500 μm to 1000 μm.

11. The polysilicon fractured product according to claim 1 , wherein a concentration of metal impurities on the surface of the product is 2 ppb or less.

12. The polysilicon fractured product according to claim 1 , wherein a concentration of iron, chromium, nickel, copper, zinc, sodium, calcium, and tungsten on a surface of the product is 0.1 ppb or less in terms of element for each metal.

13. A polysilicon package according to claim 8 , wherein the resin bag comprises a film having a thickness of about 150 μm to 900 μm.

14. A polysilicon package filled with the polysilicon fractured product according to claim 2 in a resin bag.

15. A polysilicon package according to claim 8 , wherein the resin bag comprises a polyethylene resin.

16. The polysilicon fractured product according to claim 1 , wherein a ratio of a ridge portions having a radius of curvature of 30 μm or less is 10% or less, with respect to all measured ridge portions present in the fractured polysilicon pieces.

17. A method for producing a polysilicon fractured product according to claim 1 , comprising:
fracturing a polysilicon rod to obtain fractured pieces; and
etching at an etching speed of 2.5 μm/min or less to achieve an etching depth of 5 μm or more by immersing the fractured pieces obtained in the fracturing in an etching solution consisting essentially of a mixed acid aqueous solution containing 0.5% by mass to 10% by mass of hydrofluoric acid and 48% by mass to 68% by mass of nitric acid, while applying vibration with a vibration frequency of 3 times/min to 10 times/min and a vibration amplitude of 5 mm to 1000 mm.

Assignees

• Tokuyama Corp

Inventors

• Namekawa Manato

Classifications

• C01P2004/60

  Particles characterised by their size · CPC title

• B65D77/00

  Packages formed by enclosing articles or materials in preformed containers, e.g. boxes, cartons, sacks or bags · CPC title

• Y02W30/62

  Plastics recycling; Rubber recycling · CPC title

• C09K13/08 Primary

  containing a fluorine compound · CPC title

• C01B33/02 Primary

  Silicon (forming single crystals or homogeneous polycrystalline material with defined structure C30B) · CPC title