# US 8,541,328 B2 · Ceramic material, member for semiconductor manufacturing equipment, sputtering target member and method for producing ceramic material

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- Number: US 8,541,328 B2
- Document ID: US8541328B2
- Status: Granted
- Kind: B2
- Application number: 13/478,591
- Filed: 2012-05-23
- Published: 2012-09-13
- Granted: 2013-09-24
- Earliest claimed: 2010-10-25
- Assignees: NGK Insulators, Ltd.
- Applicants: Morimichi Watanabe; Asumi Jindo; Yuji Katsuda; Yosuke Sato; Yoshinori Isoda
- Inventors: Morimichi Watanabe; Asumi Jindo; Yuji Katsuda; Yosuke Sato; Yoshinori Isoda
- Web page: https://patentgrep.com/patent/US8541328B2

## CPC

- H10P 72/722: {Details of electrostatic chucks}
- C04B 35/58: based on borides, nitrides, {i.e. nitrides, oxynitrides, carbonitrides or oxycarbonitrides} or silicides {(containing free binder metal C22C29/00)}
- C04B 35/581: based on aluminium nitride
- C04B 35/6261: {Milling}
- C04B 35/62655: {Drying, e.g. freeze-drying, spray-drying, microwave or supercritical drying}
- C04B 35/645: Pressure sintering
- C23C 14/3414: {Metallurgical or chemical aspects of target preparation, e.g. casting, powder metallurgy}
- C04B 2235/3206: Magnesium oxides or oxide-forming salts thereof
- C04B 2235/3217: Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
- C04B 2235/3222: Aluminates other than alumino-silicates, e.g. spinel (MgAl2O4)
- C04B 2235/3865: Aluminium nitrides
- C04B 2235/3869: Aluminium oxynitrides, e.g. AlON, sialon
- C04B 2235/5445: submicron sized, i.e. from 0,1 to 1 micron
- C04B 2235/762: Cubic symmetry, e.g. beta-SiC
- 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
- C04B 2235/9669: Resistance against chemicals, e.g. against molten glass or molten salts
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- 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
- C23C: COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL (making metal-coated products by extrusion B21C23/22; covering with metal by connecting pre-existing layers to articles, see the relevant places, e.g. B21D39/00, B23K; metallising of glass C03C; metallising mortars, concrete, artificial stone, ceramics or natural stone C04B41/00; enamelling of, or applying a vitreous layer to, metals C23D; treating metal surfaces or coating of metals by electrolysis or electrophoresis C25D; single-crystal film growth C30B; by metallising textiles D06M11/83; decorating textiles by locally metallising D06Q1/04)

## Abstract

A ceramic material according to the present invention mainly contains magnesium, aluminum, oxygen, and nitrogen, the ceramic material has the crystal phase of a MgO—AlN solid solution in which aluminum nitride is dissolved in magnesium oxide, the crystal phase serving as a main phase. Preferably, XRD peaks corresponding to the (200) and (220) planes of the MgO—AlN solid solution measured with CuKα radiation appear at 2θ=42.9 to 44.8° and 62.3 to 65.2°, respectively, the XRD peaks being located between peaks of cubic magnesium oxide and peaks of cubic aluminum nitride. More preferably, the XRD peak corresponding to the (111) plane appears at 2θ=36.9 to 39°, the XRD peak being located between a peak of cubic magnesium oxide and a peak of cubic aluminum nitride.

## Claims

### Claim 1

A ceramic material comprising:
magnesium, aluminum, oxygen, and nitrogen, which are main components,
wherein the ceramic material has a crystal phase of a MgO—AlN solid solution in which aluminum nitride is dissolved in magnesium oxide, the crystal phase serving as a main phase; and
wherein XRD peaks corresponding. to (200) and (220) planes of the MgO—AlN solid solution measured with CuKα radiation appear at 2θ=42.9 to 44.8° and 62.3 to 65.2°, respectively, the XRD peaks being located between peaks of cubic magnesium oxide and peaks of cubic aluminum nitride.

### Claim 2 (depends on 1)

The ceramic material according to claim 1, wherein XRD peaks corresponding to the (111) planes of the MgO—AlN solid solution measured with CuKα radiation appear at 2θ=36.9 to 39°, the XRD peaks being located between peaks of cubic magnesium oxide and peaks of cubic aluminum nitride.

### Claim 3 (depends on 1)

The ceramic material according to claim 1, wherein XRD peaks corresponding to the (200) and (220) planes of the MgO—AlN solid solution appear at 2θ=42.92° or more and 62.33° or more, respectively.

### Claim 4 (depends on 1)

The ceramic material according to claim 1, wherein XRD peaks corresponding to the (200) and (220) planes of the MgO—AlN solid solution appear at 2θ=42.95° or more and 62.35° or more, respectively.

### Claim 5 (depends on 1)

The ceramic material according to claim 1, wherein XRD peaks corresponding to the (200) and (220) planes of the MgO—AlN solid solution appear at 2θ=43.04° or more and 62.50° or more, respectively.

### Claim 6 (depends on 1)

The ceramic material according to claim 1, wherein XRD peaks corresponding to the (200) and (220) planes of the MgO-AIN solid solution appear at 2θ=43.17° or more and 62.72° or more, respectively.

### Claim 7 (depends on 3)

The ceramic material according to claim 3, wherein the integral breadth of an XRD peak corresponding to the (200) plane of the MgO—AlN solid solution is 0.50° or less.

### Claim 8 (depends on 3)

The ceramic material according to claim 3, wherein the integral breadth of an XRD peak corresponding to the (200) plane of the MgO—AlN solid solution is 0.35° or less.

### Claim 9 (depends on 3)

The ceramic material according to claim 3, wherein the ceramic material does not contain an AlN crystal phase.

### Claim 10 (depends on 3)

The ceramic material according to claim 3, wherein the ceramic material contains a magnesium-aluminum oxynitride phase as a subphase, wherein an XRD peak of the magnesium-aluminum oxynitride phase measured with CuKα radiation appears at at least 2θ=47 to 49° .

### Claim 11 (depends on 10)

The ceramic material according to claim 10, wherein letting the XRD peak intensity of the magnesium-aluminum oxynitride phase observed at 2θ=47 to 49° be A, and letting the intensity of the XRD peak corresponding to the (220) plane of the MgO—AlN solid solution observed at 2θ=62.3 to 65.2° be B, the value of A/B is 0.03 or more.

### Claim 12 (depends on 11)

The ceramic material according to claim 11, wherein the value of A/B is 0.14 or less.

### Claim 13 (depends on 10)

The ceramic material according to claim 10, wherein letting the area of the XRD peak of the magnesium-aluminum oxynitride phase observed at 2θ=47 to 49° be a, letting the area of the XRD peak corresponding to the (220) plane of the MgO—AlN solid solution observed at 2θ=62.3 to 65.2° be b, letting the area of the XRD peak corresponding to the (400) plane of spinel (MgAl2O4) observed at 2θ=45.0° be c, and letting the area of the XRD peak corresponding to the (002) plane of aluminum nitride (AlN) at 2θ=36.0° be d, the value of (a +c +d)/(a +b +c +d) is 0.1 or less.

### Claim 14 (depends on 3)

The ceramic material according to claim 3, wherein a precursor of the ceramic material is a mixed powder containing 49% by mass to 99% by mass magnesium oxide, 0.5% by mass to 25% by mass aluminum nitride, and 0.5% by mass to 30% by mass aluminum oxide.

### Claim 15 (depends on 3)

The ceramic material according to claim 3, wherein a precursor of the ceramic material is a mixed powder containing 50% by mass to 75% by mass magnesium oxide, 5% by mass to 20% by mass aluminum nitride, and 15% by mass to 30% by mass aluminum oxide.

### Claim 16 (depends on 3)

A member for use in semiconductor manufacturing equipment the member comprising the ceramic material according to claim 3.

### Claim 17 (depends on 3)

A sputtering target member comprising the ceramic material according to claim 3.

### Claim 18 (depends on 17)

A tunnel barrier of a magnetic tunnel junction device produced by the sputtering target member according to claim 17.

### Claim 19 (depends on 17)

At least one magnetic tunnel junction device selected from magnetic heads of hard disks and magnetoresistive random access memories produced by the sputtering target member according to claim 17.

### Claim 20 (depends on 3)

A method for producing a ceramic material according to claim 3, the method comprising a step of subjecting a mixed powder of magnesium oxide, aluminum oxide, and aluminum nitride to hot-press sintering in an inert atmosphere.