# US 7,744,780 B2 · Yttrium oxide material, member for use in semiconductor manufacturing apparatus, and method for producing yttrium oxide material

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- Number: US 7,744,780 B2
- Document ID: US7744780B2
- Status: Granted
- Kind: B2
- Application number: 12/369,106
- Filed: 2009-02-11
- Published: 2009-08-13
- Granted: 2010-06-29
- Earliest claimed: 2008-02-13
- Assignees: NGK Insulators, Ltd.
- Inventors: Yoshimasa Kobayashi; Yuji Katsuda
- Web page: https://patentgrep.com/patent/US7744780B2

## CPC

- C04B 35/505: based on yttrium oxide
- C04B 35/6261: {Milling}
- C04B 35/645: Pressure sintering
- C04B 2235/3206: Magnesium oxides or oxide-forming salts thereof
- C04B 2235/3208: Calcium oxide or oxide-forming salts thereof, e.g. lime
- C04B 2235/3217: Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
- C04B 2235/3224: Rare earth oxide or oxide forming salts thereof, e.g. scandium oxide
- C04B 2235/3225: Yttrium oxide or oxide-forming salts thereof
- C04B 2235/3227: Lanthanum oxide or oxide-forming salts thereof
- C04B 2235/3826: Silicon carbides
- C04B 2235/3873: Silicon nitrides, e.g. silicon carbonitride, silicon oxynitride
- C04B 2235/445: Fluoride containing anions, e.g. fluosilicate
- C04B 2235/5436: micrometer sized, i.e. from 1 to 100 micron
- C04B 2235/656: characterised by specific heating conditions during heat treatment
- C04B 2235/77: Density
- C04B 2235/80: Phases present in the sintered or melt-cast ceramic products other than the main phase
- C04B 2235/96: Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance
- H10P 72/72: using electrostatic chucks
- C04B: LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE {(roofing granules E04D7/005)}; CERAMICS (devitrified glass-ceramics C03C10/00); REFRACTORIES; TREATMENT OF NATURAL STONE
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10

## Abstract

A substrate of an electrostatic chuck, which is a member for use in a semiconductor manufacturing apparatus, is formed of an yttrium oxide material that contains yttrium oxide (Y2O3), silicon carbide (SiC), and a compound that contains a rare-earth element (RE), Si, O, and N. The yttrium oxide material contains RE8Si4N4O14 as a compound that contains a rare-earth element (RE), Si, O, and N, wherein RE may be La or Y. Y8Si4N4O14 is produced during a sintering step of a raw material that contains the main component Y2O3 and an accessory component Si3N4. Y8Si4N4O14 and SiC in the yttrium oxide material improve mechanical strength and volume resistivity.

## Claims

### Claim 1

An yttrium oxide material comprising Y2O3, SiC, and a compound, the compound containing a rare-earth element (RE), Si, O, and N.

### Claim 2 (depends on 1)

The yttrium oxide material according to claim 1, wherein the compound is RE8Si4N4O14 (RE denotes a rare-earth element).

### Claim 3 (depends on 1)

The yttrium oxide material according to claim 1, wherein the RE is Y.

### Claim 4 (depends on 1)

The yttrium oxide material according to claim 1, further comprising fluorine.

### Claim 5 (depends on 1)

The yttrium oxide material according to claim 1, wherein the SiC has an average particle size of 4 μm or less.

### Claim 6 (depends on 1)

The yttrium oxide material according to claim 1, wherein the yttrium oxide material has a four-point bending strength of at least 250 MPa.

### Claim 7 (depends on 1)

The yttrium oxide material according to claim 1, wherein the yttrium oxide material has a fracture toughness of at least 1.5 MPa·m1/2.

### Claim 8 (depends on 1)

The yttrium oxide material according to claim 1, wherein the yttrium oxide material has a volume resistivity of at least 1×1015 Ωcm at 20° C.

### Claim 9 (depends on 1)

A member for use in a semiconductor manufacturing apparatus, comprising an yttrium oxide material according to claim 1.

### Claim 10

A method for producing an yttrium oxide material, comprising the step of:
firing a mixture of Y2O3, SiC, and inorganic particles at a temperature in the range of 1500° C. to 1850° C., the inorganic particles being converted into a compound that contains a rare-earth element (RE), Si, O, and N.

### Claim 11 (depends on 10)

The method according to claim 10, wherein the inorganic particles comprise Si3N4 and Y2O3.

### Claim 12 (depends on 10)

The method according to claim 10, the mixture further comprises at least one compound selected from the group consisting of YF3, MgF2, CaF2, and AlF3.

### Claim 13 (depends on 10)

The method according to claim 10, wherein the firing step is performed at a temperature in the range of 1600° C. to 1700° C.