Silicon nitride powder production method, silicon nitride powder, silicon nitride sintered body and circuit substrate using same

Patent metadata

Field	Value
Publication number	US-9085462-B2
Application number	US-201314387281-A
Country	US
Kind code	B2
Filing date	Mar 25, 2013
Priority date	Mar 28, 2012
Publication date	Jul 21, 2015
Grant date	Jul 21, 2015

Abstract

A method of producing a silicon nitride powder includes heating an amorphous Si—N(—H)-based compound in which assuming that the specific surface area is RS (m 2 /g) and the oxygen content ratio is RO (mass %), RS/RO is 500 or more, at a temperature rising rate of 12 to 100° C./min in a temperature range from 1,000 to 1,400° C. while flowing the compound by a continuous firing furnace.

First claim

The invention claimed is:

1. A method of producing a silicon nitride powder comprising firing an amorphous Si—N(—H)-based compound having a specific surface area of 400 to 1,200 m 2 /g at a temperature of 1,400 to 1,700° C. in a nitrogen-containing inert gas atmosphere or a nitrogen-containing reducing gas atmosphere while flowing the compound in a continuous firing furnace, wherein:
assuming that a specific surface area of said amorphous Si—N(—H)-based compound is RS (m 2 /g) and an oxygen content ratio is RO (mass %), RS/RO is 500 or more, and
during said firing, said amorphous Si—N(—H)-based compound is heated at a temperature rising rate of 12 to 100° C/min in a temperature range from 1,000 to 1,400° C.

2. The method according to claim 1 , wherein:
the specific surface area of said silicon nitride powder is from 5 to 30 m 2 /g, and
assuming that the content ratio of oxygen existing in a region from a particle surface to 3 nm beneath the particle surface is FSO (mass %), the content ratio of oxygen existing in a more inward side than 3 nm beneath the particle surface is FIO (mass %), and the specific surface area is FS (m 2 /g),
FS/FSO is from 8 to 25, and
FS/FIO is 22 or more.

3. The method according to claim 2 , wherein when said silicon nitride powder is measured for a particle size distribution on a volume basis by a laser diffraction particle size distribution meter, the ratio D10/D90 between a 10 vol % diameter D10 and a 90 vol % diameter D90 is 0.1 or more.

4. The method according to claim 1 , wherein said amorphous Si—N(—H)-based compound is represented by Si 6 N 2x (NH) 12-3x (provided that x=0.5 to 4 and the compound includes a compound containing a halogen as an impurity).

5. The method according to claim 1 , wherein said RS/RO is 1,000 or more.

6. The method according to of claim 1 , wherein said temperature rising rate is from 15 to 60° C./min.

7. The method according to claim 1 , wherein the temperature range during said firing is from 1,400 to 1,600° C.

8. A silicon nitride powder having a specific surface area from 5 to 30 m 2 /g; wherein, assuming that the content ratio of oxygen existing in a region from a particle surface to 3 nm beneath the particle surface is FSO (mass%), the content ratio of oxygen existing in a more inward side than 3 nm beneath the particle surface is FIO (mass %), and a specific surface area is FS (m 2 /g), FS/FSO is from 8 to 25 and FS/FIO is 22 or more; and when a particle size distribution on a volume basis is measured by a laser diffraction particle size distribution meter, the ratio D10/D90 between a 10 vol % diameter D10 and a 90 vol % diameter D90 is 0.1 or more.

9. The silicon nitride powder according to claim 8 , which does not contain metallic silicon.

10. The silicon nitride powder according to claim 8 , wherein said specific surface area is from 7 to 25 m 2 /g, said FS/FSO is from 10 to 22, and FS/FIO is 25 or more.

11. A silicon nitride sintered body obtained by sintering the silicon nitride powder according to claim 8 .

12. The silicon nitride sintered body according to claim 11 , having a relative density of 99% more, a bending strength at room temperature of 1,000 MPa or more, and a bending strength at 1,200° C. of 600 MPa or more.

13. The silicon nitride sintered body according to claim 11 , having a relative density of 99% more, a bending strength at room temperature of 600 MPa or more, and a coefficient of thermal conductivity of 100 W/mK or more.

14. A circuit substrate comprising the silicon nitride sintered body according to claim 13 .

15. The method according to claim 2 , wherein said amorphous Si—N(—H)-based compound is represented by Si 6 N 2x (NH) 12-3x (provided that x=0.5 to 4 and the compound includes a compound containing a halogen as an impurity).

16. The silicon nitride powder according to claim 9 , wherein said specific surface area is from 7 to 25 m 2 /g, said FS/FSO is from 10 to 22, and FS/FIO is 25 or more.

17. A silicon nitride sintered body obtained by sintering the silicon nitride powder according to claim 9 .

18. A silicon nitride sintered body obtained by sintering the silicon nitride powder according to claim 10 .

19. The method according to claim 2 , wherein said RS/RO is 1,000 or more.

20. The method according to claim 3 , wherein said RS/RO is 1,000 or more.

Assignees

• Ube Industries
• Ube Industries

Inventors

• Shibata Koji
• Ohmaru Takuji
• Yamao Takeshi
• Fujinaga Masataka
• Honda Michio
• Fujii Takayuki

Classifications

• C04B2235/723

  Oxygen content · CPC title

• C04B2235/96

  Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance · CPC title

• C01P2006/12

  Surface area · CPC title

• C01P2006/80

  Compositional purity · CPC title

• C04B2235/77

  Density · CPC title