Aluminum oxide sintered body, method for producing the same and member for semiconductor producing apparatus

• US 8,231,964 B2
• Filed: 03/04/2010
• Issued: 07/31/2012
• Est. Priority Date: 03/06/2009
• Status: Active Grant

• Current Assignee: NGK Insulators Limited
• Original Assignee: NGK Insulators Limited
• Inventors: Teratani, Naomi, Katsuda, Yuji
• Primary Examiner(s): McNeil, Jennifer
• Assistant Examiner(s): Katz, Vera
• Application Number:
  US12/717,164
• Publication Number:
  US 20100227145A1
• Time in Patent Office: 880 Days
• Field of Search: None
• US Class Current: 428/220
• CPC Class Codes: C04B 2235/3217 Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
• CPC Class Codes: C04B 2235/3222 Aluminates other than alumino-silicates, e.g. spinel (MgAl2O4)
• CPC Class Codes: C04B 2235/3224 Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide
• CPC Class Codes: C04B 2235/3229 Cerium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3865 Aluminium nitrides
• CPC Class Codes: C04B 2235/5436 micrometer sized, i.e. from 1 to 100 micron
• CPC Class Codes: C04B 2235/5445 submicron sized, i.e. from 0,1 to 1 micron
• CPC Class Codes: C04B 2235/656 characterised by specific heating conditions during heat treatment
• CPC Class Codes: C04B 2235/721 Carbon content
• CPC Class Codes: C04B 2235/722 Nitrogen content
• CPC Class Codes: C04B 2235/77 Density
• CPC Class Codes: C04B 2235/78 Grain sizes and shapes, product microstructures, e.g. acicular grains, equiaxed grains, platelet-structures
• CPC Class Codes: C04B 2235/80 Phases present in the sintered or melt-cast ceramic products other than the main phase
• CPC Class Codes: C04B 2235/96 Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance
• CPC Class Codes: C04B 35/117 Composites
• CPC Class Codes: C04B 35/645 Pressure sintering

Abstract

An aluminum oxide sintered body is provided, including europium and nitrogen, and plate-like crystals having peaks coinciding with EuAl₁₂O₁₉ in an X-ray diffraction profile are dispersed over a whole sintered body. Such an aluminum oxide sintered body can be obtained by forming a mixed powder containing an alumina powder, a europium compound powder and an aluminum nitride powder into a green body having a predetermined shape, and sintering the green body under a non-oxidizing atmosphere.

Claims

1. An aluminum oxide sintered body containing:

europium and nitrogen; and

plate-like crystals having peaks coinciding with EuAl₁₂O₁₉ in an X-ray diffraction profile dispersed over the entire sintered body.

2. The aluminum oxide sintered body according to claim 1, wherein a crystal having a peak coinciding with EuAlO₃ in an X-ray diffraction profile is not present in the sintered body.

3. The aluminum oxide sintered body according to claim 1, wherein a thickness thereof is 10 mm or more.

4. The aluminum oxide sintered body according to claim 3, wherein a ratio (ρ

in/ρ

out) of the volume resistivity at room temperature (ρ

in) of an inside portion from 3 mm to 4 mm in depth from a sintered surface of the sintered body relative to the volume resistivity at room temperature (ρ

out) of an outside portion from 1 mm to 2 mm in depth from a sintered surface of the sintered body is 1.5 or less.

5. The aluminum oxide sintered body according to claim 1, wherein the volume resistivity at room temperature is from 1×

10⁸ to 1×

10¹⁴ Ω

·

cm.

6. A member for a semiconductor producing apparatus obtained by processing the aluminum oxide sintered body according to claim 1.

7. A method for producing an aluminum oxide sintered body, comprising:

forming a mixed powder containing an alumina powder, a europium compound powder and an aluminum nitride powder into a green body having a predetermined shape; and

sintering the green body under a non-oxidizing atmosphere to obtain the aluminum oxide sintered body according to claim 1.

8. The method for producing an aluminum oxide sintered body according to claim 7, wherein the mixed powder contains 2.7 to 8 parts by weight in terms of an oxide of the europium compound relative to 100 parts by weight of alumina.

9. The method for producing an aluminum oxide sintered body according to claim 7, wherein a molar ratio of the aluminum nitride powder and the europium compound powder in terms of europium oxide is from 1.7 to 2.6.

10. The method for producing an aluminum oxide sintered body according to claim 7, wherein the green body is sintered by hot-pressing at a temperature from 1600°

C. to 1800°

C.

11. The method for producing an aluminum oxide sintered body according to claim 7, wherein the green body having a predetermined shape is a plate-like form having a thickness of 20 mm or more.