JP2003300779A - Electrically conductive ceramics, production method therefor and use thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide electrically conductive ceramics which have a relative density of ≥90% and a shore hardness of ≤50, to provide a production method therefor, and to provide a vessel for metal vapor deposition which has high heat resistance and durability. <P>SOLUTION: The electrically conductive ceramics contain titanium diboride (TiB<SB>2</SB>), boron nitride (BN) and aluminum nitride (AlN) as components, and have a relative density of ≥90% and a shore hardness of ≤50. The electrically conductive ceramics are produced by subjecting mixed raw material powder containing titanium diboride, boron nitride and aluminum nitride, and one or more kinds of sintering aids selected from alkaline-earth metal oxides, rare earth element oxides and compounds to form into these oxides by heating, preferably mixed raw material powder further containing alumina powder to compacting, and thereafter performing sintering at 1,800 to 2,200°C in the presence of no carbon. The vessel for metal vapor deposition consists of the electrically conductive ceramics. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to conductive ceramics, a method for producing the same, and uses thereof.

[0002]

2. Description of the Related Art Boats made of ceramics for depositing metals such as aluminum and containers for vapor deposition of metals such as crucibles are titanium diboride, which is a conductive component, and hexagonal for imparting workability (softening) to ceramics. Crystalline boron nitride and aluminum nitride are included as constituent components in order to stabilize electrical characteristics. Since these components are difficult to sinter, pressure sintering such as hot pressing or hot isostatic pressing (HIP) is performed for manufacturing.

When sintering raw material powders containing rare earth oxides such as titanium diboride, boron nitride, aluminum nitride and yttrium oxide, Japanese Patent Laid-Open No. 3-208865 discloses adding a reducing agent such as carbon black. It is described that the sintering is promoted by JP-A-6-298566 and the sintering is performed by using a heating element made of a carbon material and a heat insulating material. However, in the sintering under such a carbon atmosphere, alkaline earth metal oxides and / or
Alternatively, the sintering aid of the rare earth element oxide readily reacts with nitrogen gas. For example, if the Y ₂ O _3, the _{Y 2 O 3 + N 2 +} 3C → 2YN + 3CO, is reduced to yttrium nitride.

For this reason, the function of the sintering aid is lowered, and in the sintering in the presence of carbon, the density is 90% or more and the Shore hardness is 50.
The following conductive ceramics could not be manufactured. The shore hardness referred to here is the hardness obtained from the jumping height of a hammer dropped from a certain height on the test surface, and can be used as an index of the workability of ceramics. Generally, a ceramic having a relative density of 90% or more has a Shore hardness of more than 50, and thus it is extremely difficult to process it into a complicated shape such as a metal evaporation container.

[0005]

SUMMARY OF THE INVENTION In view of the above, an object of the present invention is to provide a conductive ceramic having a relative density of 90% or more and a Shore hardness of 50 or less, a method for producing the same, and a metal vaporization of boats, crucibles, etc. using the same. To provide a container for use. The object of the present invention is one or more calcined materials selected from titanium diboride, boron nitride, aluminum nitride, and alkaline earth metal oxides, rare earth element oxides, and compounds that become these oxides by heating. This can be achieved by molding a mixed raw material powder containing a co-agent and then sintering it in the absence of carbon.

[0006]

That is, the present invention comprises titanium diboride (TiB ₂ ), boron nitride (BN) and aluminum nitride (AlN) as components and has a relative density of 90% or more,
A conductive ceramic having a Shore hardness of 50 or less. Further, the present invention is one or more selected from titanium diboride, boron nitride, aluminum nitride, alkaline earth metal oxides, rare earth element oxides and compounds which become these oxides by heating. Mixed raw material powder containing a sintering aid of, preferably mixed raw material powder further containing alumina powder is sintered at 1800 to 2200 ° C. in the absence of carbon after molding. It is a method for producing a porous ceramic. Furthermore, the present invention is a metal vapor deposition container comprising the above-mentioned conductive ceramics.

[0007]

The present invention will be described in more detail below.

The conductive ceramics of the present invention include titanium diboride 20 to 70% (mass%, the same applies hereinafter), boron nitride 3 to.
It is preferably 40% and aluminum nitride 10 to 60%. If the content of titanium diboride is less than 20%, the specific resistance value becomes high, and if it exceeds 70%, it is difficult to make the relative density 90% or more. Further, when the boron nitride content is less than 3% or the aluminum nitride content is more than 60%, the Shore hardness is more than 50, the boron nitride content is more than 40%, or the aluminum nitride content is 1%.
If it is less than 0%, it is difficult to achieve a relative density of 90% or more.
The ratio of these components can be determined by EPMA. The size of titanium diboride particles, boron nitride particles, and aluminum nitride particles is preferably 0.5 to 20 μm.

In the present invention, when the relative density of the conductive ceramics is less than 90%, the durability of the metal vapor deposition container is poor, and when the Shore hardness is more than 50, the workability is deteriorated and the metal vaporization container is deteriorated. Is not easy to make.

The conductive ceramics of the present invention can be manufactured by the method of manufacturing a conductive ceramics of the present invention.

The titanium diboride used in the production method of the present invention may be obtained by any production method such as direct reaction with metallic titanium or reduction reaction of oxides such as titania. , Carbon amount 1000ppm or less,
It is more preferably 100 ppm or less. If the amount of carbon exceeds 1000 ppm, it becomes difficult to make the relative density of the conductive ceramics 90% or more.
The titanium diboride powder of the present invention has an average particle size of 5 μm or less,
It is particularly preferably 2 μm or less.

As the boron nitride, hexagonal boron nitride is preferable, and a mixture of borax and urea is added in an ammonia atmosphere at 80%.
It may be obtained by any manufacturing method such as heating at 0 ° C. or higher, a method of heating a mixture of boric acid or boron oxide and calcium phosphate to a nitrogen-containing compound such as ammonium or dicyandiamide at 1600 ° C. or higher. Furthermore, these boron nitride powders may be heated at a high temperature in a nitrogen atmosphere to further enhance the crystallinity. The average particle size of the boron nitride powder is preferably 10 μm or less, and particularly preferably 5 μm or less. Carbon content is 1000 ppm or less, especially 100
It is preferably at most ppm. Carbon amount 1000pp
When it is more than m, the relative density of the conductive ceramics is 90%.
It becomes difficult to do the above.

As the aluminum nitride, a direct nitriding method,
The powder obtained by any known method such as the alumina reduction method may be used, but a carbon content of 1000 ppm or less, particularly 100 ppm or less is preferable. If the amount of carbon exceeds 1000 ppm, it becomes difficult to make the relative density of the conductive ceramics 90% or more. The average particle size of the aluminum nitride powder is preferably 5 μm or less, and particularly preferably 1 μm or less.
If the average particle size exceeds 5 μm, it becomes difficult to manufacture a conductive ceramic having a relative density of 90% or more.

Furthermore, alkaline earth metal oxides and rare earths
Oxides of group elements and conversion to these oxides by heating
One or two or more sintering aids selected from compounds (hereinafter,
Simply called "sintering aid". ) Is CaO, Mg
O, SrO, BaO, Y₂O₃, La₂O₃, Ce₂O₃, P
r₂O₃, Nd₂O₃, Pm₂O₃, Sm₂O₃, Eu₂O₃, G
d₂O₃, Tb₂O₃, Dy₂O₃, Ho₂O₃, Er₂O₃, T
m₂O₃, Yb₂O₃, Lu ₂O₃Etc., and further Ca
(OH)₂Hydroxides such as MgCO₃Carbonate, etc.
It may be a compound that becomes an oxide by heat. Arca
Particle size of rare earth metal oxide and / or rare earth element oxide
Is preferably 5 μm or less, particularly 1 μm or less in average particle size.
Yes. When the average particle size exceeds 5 μm, the relative density is 90%
Less than

The mixing ratio of titanium diboride, boron nitride, aluminum nitride, and sintering aid is 4 to 200 parts of boron nitride and 15 parts of aluminum nitride to 100 parts of titanium diboride (mass parts, the same hereinafter). ~ 300 parts, sintering aid 0.2-10
Parts are preferred. When the boron nitride content is less than 4 parts or the aluminum nitride content exceeds 300 parts, the Shore hardness exceeds 50, and when the boron nitride content is more than 200 parts or the aluminum nitride content is less than 15 parts, a conductive ceramic having a relative density of 90% or more. Is difficult to manufacture. If the amount of the sintering aid is less than 0.2 part, it is difficult to achieve a relative density of 90% or more, and if it is more than 10 parts, the aluminate of the sintering aid precipitates as a liquid phase on the surface and stains. Occurs and the commercial value is reduced.

When the mixed raw material powder contains 10 parts or less, particularly 1 to 5 parts, of alumina based on 100 parts of titanium diboride, the relative density can be further increased. As alumina, Bayer method, fused alumina,
It may be any of ultrafine particle alumina produced by a vapor phase method. The average particle size of alumina is 5 μm or less, and particularly preferably 1 μm or less. Carbon amount is 1000p
It is preferably pm or less, and particularly preferably 100 ppm or less.

In the present invention, the mixed raw material powder is preferably formed after granulation. The particle size is preferably 0.1 to 5 mm. Molding / sintering is 0.5-200MP
a, especially after uniaxial pressurization of 5 to 100 MPa or cold isostatic pressurization, then 1800 to 2200 ° C., especially 1900 to 20
A method of sintering at 00 ° C. under normal pressure or low pressure of 1 MPa or less,
After uniaxial pressing or cold isostatic pressing under the above conditions, 1800-
It is carried out by hot pressing or hot isostatic pressing at 2200 ° C. and 1 to 100 MPa. According to the former, it is possible to achieve a relative density of 90% or more, but 95%
The above is difficult. On the other hand, according to the latter, if the temperature-pressure conditions are selected, conductive ceramics having a relative density of 95% or more and a Shore hardness of 30 or less can be manufactured. If the sintering temperature is less than 1800 ° C., the densification will be insufficient, and if it exceeds 2200 ° C., stains will occur and the commercial value will decrease.

What is important in the present invention is that the above sintering is performed in the absence of carbon, preferably using a boron nitride jig. Specifically, it is housed in a container made of boron nitride or a container lined with boron nitride and sintered, or in the hot pressing method, a sleeve made of boron nitride or a sleeve lined with boron nitride is used for sintering. . The sintering atmosphere may be helium, neon, argon, vacuum, or the like, in addition to nitrogen, without any problem.

The electroconductive ceramics of the present invention can be used as a metal vapor deposition container such as a boat or a crucible for metal vapor deposition. Evaporative metals include aluminum, copper,
It is silver, zinc, or the like, which is placed in a metal evaporation container and resistance-heated under vacuum to a high temperature equal to or higher than the melting point of the metal, so that the metal can be vapor-deposited on the film or other ceramics.

[0020]

EXAMPLES Hereinafter, the present invention will be described more specifically by way of examples.

Example 1 Titanium diboride (average particle size 3.7 μm, carbon amount 75 pp)
m) to 100 parts, boron nitride 50 parts (the same 2.3 μm,
A carbon content of 40 ppm), aluminum nitride 100 parts (0.7 μm, carbon content of 55 ppm), and a sintering aid were blended at a blending ratio shown in Table 1 to prepare a mixed raw material powder, 50 m
After molding into m × 20 mm × 200 mm (cold isotropic pressure pressurization, pressure 30 MPa), it was housed in a boron nitride container and sintered at 1900 ° C. for 2 hours under normal pressure in a nitrogen atmosphere. A boat for metal vapor deposition was processed from the obtained conductive ceramics, and the following characteristics were measured. The results are shown in Table 2.
Shown in.

(1) Relative density: Calculated from measured density and theoretical density. (2) Shore hardness: measured according to JIS Z 2246. (3) Service life of boat: Boat for metal deposition (width 30m
m × thickness 10 mm × length 150 mm) is processed, and metal aluminum is processed (groove 26 mm × thickness 2 mm × length 9)
0mm), and put 1.00g, in vacuum, boat temperature 1
Electricity was applied at 600 ° C. Repeat this vapor deposition test,
The number of times the boat was repeatedly used when the boat was cracked or aluminum could not be vapor-deposited was measured. In addition, as a highly durable boat, the number of times of repeated use of 100 times or more is required.

[0023]

[Table 1]

[0024]

[Table 2]

Example 2 A conductive ceramic was produced in the same manner as in Example 1 except that hot pressing sintering was performed using a boron nitride sleeve, and an evaluation test of a boat for metal deposition was performed. The results are shown in Table 3.

[0026]

[Table 3]

Comparative Example 1 According to Example 2 (Experiment Nos. 7 and 12 to 15), except that a carbon sleeve was used instead of the boron nitride sleeve, and pressure baking was performed using a hot press. Conductive ceramics were manufactured by the above, and the evaluation test of the boat for metal deposition was performed. The results are shown in Table 4.

[0028]

[Table 4]

Example 3 Example 1 was repeated, except that in Experiment Nos. 1, 3, 6 and 13, a mixed raw material powder further containing 2 parts of alumina powder (average particle size 0.7 μm, carbon amount 20 ppm) was used. Alternatively, a conductive ceramic was manufactured according to the method described in 2 above, and an evaluation test of a boat for metal deposition was performed. The results are shown in Table 5.

[0030]

[Table 5]

[0031]

According to the present invention, the relative density is 90% or more,
A conductive ceramic having a Shore hardness of 50 or less is provided. The conductive ceramics of the present invention have good workability,
Since it has high heat resistance and durability, it can be suitably used as a metal vapor deposition container or the like. According to the method for producing a conductive ceramic of the present invention, it is possible to easily produce a conductive ceramic having the above-mentioned characteristics.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shinichi Takada             1 Shinkaimachi, Omuta City, Fukuoka Prefecture             Ceremony company Omuta factory F-term (reference) 4G001 BA03 BA07 BA08 BA09 BA33                       BA36 BA44 BB03 BB07 BB08                       BB09 BB33 BB36 BB44 BC13                       BC23 BC42 BC43 BC46 BC52                       BC54 BC62 BD07 BD22                 4K029 CA01 DB03 DB13                 5G301 CA03 CA04 CA12 CA25 CD10                       CE02

Claims (4)

[Claims] 1. A conductive ceramic comprising titanium diboride (TiB ₂ ), boron nitride (BN) and aluminum nitride (AlN) as a component and having a relative density of 90% or more and a Shore hardness of 50 or less. 2. One or more selected from titanium diboride, boron nitride, aluminum nitride, alkaline earth metal oxides, rare earth element oxides, and compounds that become these oxides by heating. After forming a mixed raw material powder containing a sintering aid, 1800 to 2200 in the absence of carbon after molding.
The method for producing a conductive ceramic according to claim 1, wherein sintering is performed at a temperature of ° C. 3. The method for producing a conductive ceramic according to claim 2, wherein the mixed raw material powder further contains alumina powder. 4. A metal vapor deposition container comprising the conductive ceramics according to claim 1.