ALUMINA SINTERED BODY, METHOD FOR MANUFACTURING THE SAME, AND SEMICONDUCTOR MANUFACTURING APPARATUS MEMBER

• US 20100248935A1
• Filed: 03/12/2010
• Published: 09/30/2010
• Est. Priority Date: 03/26/2009
• Status: Active Grant

• Current Assignee: NGK Insulators Limited
• Original Assignee: NGK Insulators Limited
• Inventors: Hayase, Toru, Kida, Masahiro, Katsuda, Yuji, Teratani, Naomi
• Granted Patent: US 8,178,455 B2
• Time in Patent Office: Days
• US Class Current: 501/119
• CPC Class Codes: B32B 18/00 Layered products essentially comprising ceramics, e.g. refractory products
• CPC Class Codes: C04B 2235/3206 Magnesium oxides or oxide-forming salts thereof
• CPC Class Codes: C04B 2235/3208 Calcium oxide or oxide-forming salts thereof, e.g. lime
• 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 2235/445 Fluoride containing anions, e.g. fluosilicate
• 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 2235/6567 Treatment time
• CPC Class Codes: C04B 2235/658 Atmosphere during thermal treatment
• CPC Class Codes: C04B 2235/6581 Total pressure below 1 atmosphere, e.g. vacuum
• CPC Class Codes: C04B 2235/77 Density
• CPC Class Codes: C04B 2235/786 Micrometer sized grains, i.e. from 1 to 100 micron
• 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 2235/963 Surface properties, e.g. surface roughness
• CPC Class Codes: C04B 2237/343 Alumina or aluminates
• CPC Class Codes: C04B 35/111 Fine ceramics
• CPC Class Codes: C04B 35/645 Pressure sintering

Abstract

A method for manufacturing an alumina sintered body of the present invention comprises: (a) forming a mixed powder containing at least Al₂O₃ and MgF₂ or a mixed powder containing Al₂O₃, MgF₂, and MgO into a compact having a predetermined shape; and (b) performing hot-press sintering of the compact in a vacuum atmosphere or a non-oxidizing atmosphere to form an alumina sintered body, in which when a amount of MgF₂ to 100 parts by weight of Al₂O₃ is represented by X (parts by weight), and a hot-press sintering temperature is represented by Y (° C.), the hot-press sintering temperature is set to satisfy the following equations (1) to (4)

1,120≦Y≦1,300  (1)

0.15≦X≦1.89  (2)

Y≦−78.7X+1,349  (3)

Y≧−200X+1,212  (4).

Claims

1. A method for manufacturing an alumina sintered body comprising the steps of:

(a) forming a mixed powder containing at least Al₂O₃ and MgF₂ or a mixed powder containing Al₂O₃, MgF₂, and MgO into a compact having a predetermined shape; and

(b) hot-press sintering of the compact in a vacuum atmosphere or a non-ozidizing atmosphere to form an alumina sintered body, in which when a amount of MgF₂ to 100 parts by weight of Al₂O₃ is represented by X (parts by weight), and a hot-press sintering temperature is represented by Y (°

C.), the hot-press sintering temperature is set to satisfy the following equations (1) to (4),

1,120≦

Y≦

1,300 

 

(1)

0.15≦

X≦

1.89 

 

(2)

Y≦

−

78.7X+1,349 

 

(3)

Y≧

−

200X+1,212 

 

(4).

2. The method for manufacturing an alumina sintered body according to claim 1,

wherein in the step (a), when or after the mixed powder is formed into the compact, a first electrode raw material containing WC, Al₂O₃, and at least one transition metal selected from the group consisting of Ni and Co or a second electrode raw material containing Al₂O₃ and at least one transition metal selected from the group consisting of Ni and Co is shaped into a predetermined shape and is embedded in or laminated on the compact.

9. The alumina sintered body according to claim 3, wherein the alumina sintered body is manufactured by the method for manufacturing an alumina sintered body according to claim 1.

10. The alumina sintered body that is manufactured by the method for manufacturing an alumina sintered body according to claim 2,

wherein the alumina sintered body comprises magnesium and fluorine, in which a constituent crystalline phase is composed of only Al₂O₃, or as at least one constituent phase other than that of alumina, MgF₂ or MgF₂ and MgAl₂O₄ are contained, wherein an open porosity is less than 0.1%, the bulk density is 3.95 g/cm³ or more, and a volume resistivity calculated from a current value 1 minute after application of 2 kV/mm at room temperature is 1×

10¹⁴ Ω

·

cm or more, and

a first electrode containing WC, Al₂O₃, and at least one transition metal selected from the group consisting of Ni and Co or a second electrode containing Al₂O₃ and at least one transition metal selected from the group consisting of Ni and Co is embedded or laminated.

11. A semiconductor manufacturing apparatus member at least partly composed of an alumina sintered body which is manufactured by the method for manufacturing an alumina sintered body according to claim 1.

12. A semiconductor manufacturing apparatus member at least partly composed of an alumina sintered body which is manufactured by the method for manufacturing an alumina sintered body according to claim 2.

3. An alumina sintered body comprising magnesium and fluorine, in which a constituent crystalline phase is composed of only Al₂O₃, or as at least one constituent phase other than that of alumina, MgF₂ or MgF₂ and MgAl₂O₄ are contained, wherein an open porosity is less than 0.1%, the bulk density is 3.95 g/cm³ or more, and a volume resistivity calculated from a current value 1 minute after application of 2 kV/mm at room temperature is 1×

10¹⁴ Ω

·

cm or more.

4. The alumina sintered body according to claim 3, wherein a relative density is 99.5% or more.

5. The alumina sintered body according to claim 3, wherein a flexural strength is 300 MPa or more.

6. The alumina sintered body according to claim 3, wherein the alumina sintered body comprises 0.03 to 0.8 percent by weight of Mg and 0.01 to 1.2 percent by weight of F.

7. The alumina sintered body according to claim 3, wherein the alumina sintered body comprises magnesium and fluorine, at least one constituent crystalline phase is composed of only Al₂O₃, Al₂O₃ and MgF₂, or Al₂O₃, MgF₂, and MgAl₂O₄, and another crystalline phase is not included.

8. The alumina sintered body according to claim 3, wherein a first electrode containing WC, Al₂O₃, and at least one transition metal selected from the group consisting of Ni and Co or a second electrode containing Al₂O₃ and at least one transition metal selected from the group consisting of Ni and Co is embedded or laminated.

13. A semiconductor manufacturing apparatus member formed by using the alumina sintered body according to claim 3.