JPS6252180A - Aluminum nitride composition - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention provides a novel aluminum nitride composition that can be used as a raw material for aluminum nitride green sheets and aluminum nitride sintered sheets that are sintered bodies thereof.

[Prior art and problems to be solved by the invention] Conventionally, in various industrial and consumer electronic devices, ceramics have been used for mounting electronic devices such as transistors, IC's, and LSIs, forming circuits, and insulating them. board is used. For example, an alumina substrate is a typical example. However, in recent years, the heat conductivity of alumina substrates has been insufficient in fields that require particularly high thermal conductivity, such as Power I/Run Sister and high power hybrid ICs, and there has been a demand for the development of high thermal conductive ceramic substrates as an alternative. It's here. For this purpose, attempts have been made to develop highly thermally conductive ceramic substrates using various ceramics. However, a highly thermally conductive ceramic substrate that is industrially satisfactory has not yet been developed.

Based on the above background, the inventors of the present invention have earnestly attempted to develop a highly thermally conductive ceramic substrate. If only the performance of high thermal conductivity is compared, for example, an aluminum nitride sintered body has a high thermal conductivity several times that of an alumina sintered body. Therefore, with the aim of obtaining a highly thermally conductive aluminum nitride sintered sheet, the present inventors have conducted repeated research on an aluminum nitride composition that can be suitably used as a raw material for the aluminum nitride sintered sheet. As a result, an aluminum nitride green sheet that can be suitably used for producing a sintered aluminum nitride sheet and an aluminum nitride composition that is a raw material for the aluminum nitride green sheet have been discovered and have already been proposed.

(Patent Application No. 59-22982).

The present inventors have conducted further research on the above aluminum nitride composition. As a result, when sintering aluminum nitride powder using a relatively large amount of sintering aid required for sintering aluminum nitride powder, it is difficult to sinter the aluminum nitride powder while simultaneously adding an alkaline earth metal halide. It was found that the amount of sintering aid contained in the sintered sheet was extremely reduced. Furthermore, it was surprisingly found that the addition of an alkaline earth metal halide significantly improves the thermal conductivity of the sintered sheet.

Then, they discovered an aluminum nitride composition that can be used as an aluminum nitride sintered sheet that has excellent properties of an aluminum nitride sintered body, especially high thermal conductivity, because the amount of residual sintering aid is extremely small, and the present invention was completed.

[Means for solving problems]

That is, the present invention provides (i) aluminum mide powder, (i
i) a binder made of an organic polymer compound that decomposes at a temperature of 1400°C or less; (iii) a sintering aid made of a compound of at least one metal selected from the group consisting of yttrium and lanthanum group metals, and ( iv) Mainly composed of alkaline earth metal halide, the binder is 0.1 to 30 parts by weight per 100 parts by weight of aluminum nitride powder, and the sintering aid is 0.1 to 30 parts by weight per 100 parts by weight of aluminum nitride powder. This is an aluminum nitride composition in which the alkaline earth metal halide is blended in an amount of 0.01 to 10 parts by weight per 10 parts by weight of aluminum nitride powder.

Note that aluminum nitride in the present invention is a 1:1 compound of aluminum and nitrogen, and anything other than this is treated as an impurity in principle.

However, on the surface of aluminum nitride powder, the Aff-N bond, which is inevitably oxidized in the air, replaces the Aβ-〇 bond, so the aluminum with this Aj2-0 bond is not considered a cationic impurity. do not have.

Also, components that serve as sintering aids are not considered cationic impurities. Furthermore, the average particle diameter in the present invention refers to the volume-based median particle diameter measured by a light transmission type particle size distribution analyzer.

As the aluminum nitride powder used in the present invention, any known aluminum nitride powder can be used without any restriction. In general, in consideration of the thermal conductivity of the aluminum nitride sintered sheet obtained in the present invention, it is preferable to use aluminum nitride powder having an oxygen content of 3.0% by weight or less.

Further, it is preferable that the aluminum nitride powder particles used in the present invention have small particle diameters.

For example, it is preferable that the average particle diameter (meaning the average particle diameter of aggregated particles measured with a centrifugal particle size distribution analyzer such as CAPA500 manufactured by Horiba, Ltd.) is 5 μm or less.

Powder size is preferably 36 m or less, most preferably 2 μm or less. Particularly suitable is a powder containing 70% by volume or more of particles of 3 μm or less. In addition, when obtaining a highly thermally conductive aluminum nitride sintered sheet, the content of AffN (A1N
(calculated from the nitrogen content of the powder) is preferably 90% by weight or more aluminum nitride powder, and more preferably 94% by weight or more.
It is preferable to use a powder of 97% by weight or more in order to obtain a sintered body having high translucency.

The aluminum nitride powder preferably used in the present invention is a powder with an average particle size of 3 μm or less, an oxygen content of 3.0% by weight or less, and an aluminum nitride composition of A.
Cation impurities contained in IN are 0.5% by weight
The aluminum nitride powder is as follows. When such aluminum nitride powder is used, the thermal conductivity of the obtained sintered aluminum nitride sheet is greatly improved, and therefore it is preferably used in the present invention. Especially, the average particle size is 2
Powder with a diameter of 3 μm or less, containing 70% by volume or more of particles with a diameter of 3 μm or less, an oxygen content of 1.5% by weight or less, and a cationic impurity of 0.3% by weight when the aluminum nitride composition is A/N. When the following aluminum nitride powders are used, the resulting sintered aluminum nitride sheet has improved thermal conductivity and light transmittance, and is therefore particularly preferably used in the present invention.

When producing the aluminum nitride powder used in the present invention, a compound corresponding to the sintering aid described below is added to the raw material in advance, and the aluminum nitride powder obtained by firing is obtained in a form containing the sintering aid. It will be done.

Such aluminum nitride powder is used in the above (i) of the present invention.
The components (ii) and (ii) are blended in advance, and is one of the preferred usage forms.

One of the other components that make up the aluminum nitride composition of the present invention is a binder. The binder used in the present invention is 1
It is an organic polymer compound that decomposes at temperatures below 400°C. The aluminum nitride composition of the present invention, for example via an aluminum nitride green sheet, generally has a
It is sintered at a temperature of 0.000C and is suitably used as a sintered aluminum nitride sheet. In this case, if a large amount of decomposition residue of the binder remains in the sintered body, it becomes difficult to obtain the desired physical properties of the sintered body, such as high strength, high thermal conductivity, or translucency. According to the findings of the present invention, the binder having the above requirements does not substantially remain in the sintered body, or even if it remains, the amount is such that it does not impair the desired physical properties of the sintered body. It is necessary to select the type and process it. Binders that are generally used for molding ceramic powders are not particularly limited and can be used in the present invention, but in general, binders that decompose in a temperature range of 1400° C. or lower are preferred when determined by thermogravimetric analysis (TG). More preferably, a binder is selected whose decomposition residue is 5% by weight or less based on the binder.

A more specific example of the binder preferably used in the present invention is polyvinyl butyral.

Polymethyl methacrylate, cellulose acetate butyrate, nitrocellulose, polyacrylic ester,
Oxygen-containing organic polymers such as polyvinyl alcohol, methylcellulose, hydroxymethylcellulose, and polyethylene oxide.

Other hydrocarbon-based synthetic resins such as petroleum resins, polyethylene, polypropylene, and polystyrene; polyvinyl chloride;
Organic polymers such as acrylic fat crumbles and emulsions thereof; waxes and emulsions thereof are used singly or in combination of two or more. As mentioned above, the surface of the aluminum nitride powder used in the present invention is inevitably oxidized and has /l-0 bonds. Therefore, it is particularly preferable to use the oxygen-containing organic polymer as a binder since it exhibits a strong bonding force based on its excellent chemical affinity with the surface of the aluminum nitride powder. The organic polymer used as the binder is not particularly limited, but generally has a molecular weight of 3,000 to 1.
,000,000 preferably 5,000-300.00
It is more preferable to use 0 because the above-mentioned molded product, such as a green sheet, is flexible and tough and can be easily handled during various processing. Among the organic polymers, oxygen-containing organic polymers are particularly preferred, and furthermore, the molecular weight is 30,
000 to 100,000 polyvinyl butyral is most preferred. The amount of binder used varies depending on the type of binder and the type of solvent described below, and also depends on the application of the aluminum nitride composition, such as the thickness, strength and workability of the aluminum nitride green sheet, and the amount obtained by sintering the green sheet. Since it varies depending on the physical properties required for the aluminum nitride sintered sheet, it is generally not limited, but generally 0.
The amount may be selected from the range of 1 to 30 parts by weight, preferably 2.5 to 15 parts by weight, and more preferably 4 to 10 parts by weight.

One of the other components constituting the aluminum nitride composition of the present invention is a sintering aid made of a compound of at least one metal selected from the group consisting of yttrium and lanthanum group metals.

The above-mentioned lanthanum group metals can be used without particular limitation. For example, lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promedium (Pm)
, samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er)
, thulium (Tm), ytterbium (Yb), and lutetium (Lu) can be suitably used. Especially industrially, La
, Ce + Pr, Nd.

Sm + Eu + Gd + Dy etc. are preferably used. In addition, these compounds include oxides, nitrates,
Nitrites, carbonates, halides, etc. can be used without any restriction.

The amount of the sintering aid used in the present invention varies depending on the properties required of the sintered body and cannot be absolutely limited, but is generally 0.0 parts by weight per 100 parts by weight of aluminum nitride powder.
It may be selected from the range of 1 to 5 parts by weight, preferably 0.1 to 4 parts by weight. Since the amount of these additives varies depending on the oxygen content in the aluminum nitride powder, the content of impurities, the particle size, etc., the appropriate amount to be used may be determined in advance according to these properties.

One of the other components constituting the aluminum nitride composition of the present invention is an alkaline earth metal halide. The alkaline earth metal is not particularly limited, and for example, beryllium, magnesium, calcium, barium, and strontium can be suitably used.

In particular, calcium, barium, strontium, etc. are preferably used industrially. Moreover, as these halides, fluoride, chloride, bromide, iodide, etc. can be used without any restriction.

Specific examples of alkaline earth metal halides preferably used in the present invention include calcium fluoride, barium fluoride, strontium fluoride, calcium oxalide, barium oxalide, strontium oxalide, and iodide. Examples include calcium, barium iodide, strontium iodide, and the like. Among these, fluorides are preferably used because the resulting sintered aluminum nitride sheet has better thermal conductivity.

The amount of the above alkaline earth metal halide to be used varies depending on the properties required of the sintered sheet and cannot be unconditionally limited, but is generally 0.01 to 10 parts by weight per 100 parts by weight of aluminum nitride powder. Preferably, the amount may be selected from the range of 0.1 to 6 parts by weight.

As long as the amounts of the sintering aid and the alkaline earth metal halide are within the ranges mentioned above, the ratio of these amounts is not limited at all, but in order to reduce the amount of the sintering aid remaining after sintering, It is suitable that the weight ratio of sintering aid/alkaline earth metal halide is in the range of 1/10 to 5, preferably 115 to 1.

Conventionally, according to a known method, when a few percent of yttrium oxide is added as a sintering aid for aluminum nitride,
A good sintered body was obtained, and in this case, the added yttrium oxide was combined with the surface oxide of the aluminum nitride powder, and the Y
*AI! 5012 (YAG), YA l 03, A
It is known that composite oxides such as lzY40q are formed and segregated at grain boundaries in a sintered body, especially near triple junctions (Proceedings of the 60th Annual Ceramics Industry Conference, pages 517 to 518).

The fact that the above-mentioned yttrium aluminate compound remains in the sintered body is from the viewpoint of better sintered body synthesis that fully brings out the excellent properties of aluminum nitride, such as high thermal conductivity. This is a disadvantageous factor.

In order to solve the above-mentioned problems, the present inventors conducted intensive research and found that several percent of yttrium and lanthanum metal compounds were used as sintering aids, and at the same time, several percent of alkaline earth metal halides were added. When sintered, the amount of sintering aid remaining in the sintered body is reduced to 1/2 or less of the added amount, preferably 11
5 or less, more preferably 1/10 or less, and the thermal conductivity of the sintered body was found to be significantly higher than the conventionally known value. Although we do not yet know the exact cause of this, we speculate that it is due to the following reasons.

That is, the sintering aid and the surface oxide of the aluminum nitride powder combine to form an aluminate compound, and the alkaline earth metal halide acts on this to lower the melting point of the aluminate compound and densify it. At the same time, the aluminate compound is thought to volatilize out of the sintered body. For this reason, the content of yttrium or lanthanum group metals contained as aluminate compound components in the final sintered body is significantly lower than the amount added, and at the same time, the content of yttrium or lanthanum group metals contained in the aluminate compound component in the final sintered body is significantly reduced compared to the amount added. Since the layer also volatilizes as an aluminate compound, it is thought that the oxygen content in the sintered body was drastically reduced. The inventors of the present invention conjecture that these factors led to the creation of a sintered aluminum nitride sheet of high purity and high thermal conductivity, which had never been seen before.

In addition to the above-mentioned features, the present invention also has an industrial feature in that the sintering start temperature can be lowered by about 200°.

The aluminum nitride composition of the present invention is prepared by mixing the aluminum nitride powder, binder, sintering aid, and alkaline earth metal halide in the proportions described above, as well as adding a deflocculant, a plasticizer, etc. as necessary. There is no hindrance to addition and mixing, and it is often used as a preferred embodiment. For example, the above aluminum nitride powder of the present invention,
When a binder, a sintering aid, and an alkaline earth metal halide are dispersed and mixed in a solvent as described in detail later, it is often preferable to use a deflocculant to promote the dispersion. It is a mode. The deflocculant is generally cerami? Any compound known to be used in molding powder may be used without particular limitation. Specific examples of typical deflocculants that are generally suitably used include glycerin or sorbitol esters of fatty acids such as glycerin trioleate and sorbitan trioleate; natural fish; nonionic synthetic surfactants; higher fatty acids ; benzenesulfonic acid, etc. The amount of these deflocculants to be used varies depending on the type of deflocculant, the type of the mixed system to be added, etc., and cannot be absolutely limited, but in general, it is preferably 0.01 to 5 parts by weight per 100 parts by weight of aluminum nitride powder. It is preferable to select from the range of 0.1 to 3 parts by weight. The peptizer may be mixed in any order, but generally aluminum nitride powder, sintering aid, and alkaline earth metal halide are premixed with the peptizer in a dispersion medium, and then the binder is mixed. Alternatively, it is preferable to further add and mix a plasticizer, which will be described later, to prepare a slurry.

Further, the plasticizer is used for the purpose of imparting flexibility to a specific molded product when the aluminum nitride composition of the present invention is processed into a specific molded product. The plasticizer is not particularly limited, and any plasticizer known to be used for the above purpose in molding general ceramic powder can be used. Typical examples that are particularly preferably used include polyethylene glycol and its derivatives, phthalate esters such as dimethyl phthalate, dibutyl phthalate, butylbenzyl phthalate, and dioctyl phthalate; stearic acid such as butyl stearate. These include esters; tricresol phosphate; tri-N-butyl phosphate; glycerin, and the like. The amount of these plasticizers added varies depending on the type of binder, the properties of aluminum nitride, the type and amount of solvent used, etc., and cannot be absolutely limited, but it is generally 15 parts by weight or less, preferably 15 parts by weight or less per 100 parts by weight of aluminum nitride. The amount may be appropriately selected from the range of 0.4 to 15 parts by weight, more preferably 3 to 10 parts by weight.

The usage mode of the aluminum nitride composition of the present invention will be explained below. When used, it is generally preferable to use it in a form dispersed in a dispersion medium. The role of the dispersion medium is generally to disperse the aluminum nitride powder, sintering aid, and alkaline earth metal halide, and also to dissolve the binder or plasticizer used as necessary to form a uniform slurry. It is to be. After forming the slurry into a specific shape, such as a sheet, the solvent is preferably substantially removed by drying and does not remain in the aluminum nitride molded product, such as a green sheet. Therefore, the solvent in the dispersion medium part is not particularly limited as long as it satisfies the above-mentioned requirements for dispersibility, solubility and drying properties, but it is generally preferable to select a non-aqueous solvent. Specific examples of typical solvents that are particularly preferably used include acetone, ketones such as methyl ethyl ketone and methyl isobutyl ketone, alcohols such as ethanol, propatool and butanol, benzene, toluene and xylene. It is preferable to use one type or a mixture of two or more types of aromatic hydrocarbons, or halogenated hydrocarbons such as trichloroethylene, tetrachloroethylene, and bromochloromethane. The amount of solvent used is also not particularly limited, but if the amount of solvent is too large, particles of aluminum nitride powder, sintering aid, and alkaline earth metal halide will tend to settle and separate during storage, molding, or drying of the slurry. If the amount is too small, it will be difficult to form a sheet, so an appropriate amount may be selected and used in advance. Generally, the amount of the solvent depends on its type and the type and amount of binder and plasticizer, but aluminum nitride powder 10
It is suitable if the amount is selected in the range of 30 to 100 parts by weight relative to 0 parts by weight.

The mixing conditions for the aluminum nitride composition of the present invention are not particularly limited, and the mixing may be carried out at room temperature and normal pressure, and the mixing device will be explained based on the mixing mode of the raw materials for producing the aluminum nitride powder in order to prevent the mixing of impurity components. It is preferable to choose the material as shown or choose one coated with plastic. Most generally, it is preferable to use a mill that has a built-in spherical object, rod-like object, or the like. The above-mentioned mixture is generally used in the form of a viscous paint-like slurry called slurry so that it can be easily handled during molding.

The aluminum nitride composition obtained as described above, namely (i) aluminum nitride powder, (ii) binder (i)
ii) A sintering aid and (iv) an alkaline earth metal halide or, if necessary, a plasticizer, a deflocculant, etc. are mixed with a solvent to form a slurry. This slurry is formed into a film such as polyethylene, polypropylene, polyester, or polyamide using a sheet forming machine such as a doctor blade type sheet forming machine.

Formed into a sheet on a synthetic resin film such as polyvinyl chloride. Next, the sheet-like molded product is dried by scattering the solvent at a temperature between room temperature and the boiling point of the solvent to form a so-called aluminum nitride green sheet. The aluminum nitride green sheet generally has a glossy appearance, is flexible, and has strong properties against bending. The aluminum nitride green sheet has a tensile strength of 25 kg/cJ or more.

The above aluminum nitride green sheet can be used as it is for the production of a sintered sheet, which will be described later, but generally the above-mentioned binder,
The temperature at which plasticizers, peptizers, etc. are decomposed, generally e.g.
It is preferable to carry out the thermal decomposition treatment at a temperature of 00 to 1400°C, preferably 500 to 1000°C.

The aluminum nitride green sheet or the heat-treated sheet is then subjected to a sintering process. The sintering process is not particularly limited, and any known sintering method used for nitrides may be used as is. Generally, sintering may be carried out at a temperature of 1,600 to 2,100° C. under normal pressure, in an inert atmosphere, for example, in a nitrogen atmosphere. The pressure during the sintering is generally normal pressure, but a sintering furnace maintained at a certain degree of pressure with an inert gas may also be used. Further, the time required for sintering varies depending on various conditions such as the thickness of the sheet material to be sintered and the sintering temperature, and cannot be absolutely limited, but it may generally be selected from the range of 30 minutes to 24 hours. It is preferable that appropriate ranges of these conditions be determined in advance according to various conditions prior to implementation.

The sintered sheet obtained by the above sintering generally has a sintered density of 2.7 g/cm3 or more, preferably 2.9 g/cm3 or more.
cm 'More preferably 3.0g/CI! 13 or more. The sheet is generally obtained with a side length of at least 5 nm or more and a thickness in the range of 0.05 to 10 mm. These sintered sheets become sheet-like products with an excellent bending strength of at least 2 Q kg/l*''.

〔effect〕

The aluminum nitride sintered sheet obtained by the above-mentioned method using the aluminum nitride composition of the present invention as a raw material was sintered even though a sintering aid was added in an amount of several percent necessary for sintering the aluminum nitride powder. The amount of sintering aid contained after sintering is not more than 0.5% by weight, in particular not more than 0.3% by weight, even not more than 0.
．． The amount is 1% by weight or less, 1/2 or less of the amount added, preferably 115 or less, and more preferably 1/10 or less, which is a very small amount.

That is, a high-purity aluminum nitride sintered sheet, for example, an aluminum nitride sintered sheet with a metal content of 1% or less, more preferably 0.1% or less, is obtained. Furthermore, the content of alkaline earth halides is also reduced after sintering, to 0.5% by weight or less, preferably 0.1% by weight or less, in the sintered sheet. Also,
The aluminum nitride sintered sheet obtained by the present invention has an extremely low oxygen content, usually 0.5% by weight or less, and even 0.2% by weight or less. These sintered aluminum nitride sheets have extremely good thermal conductivity due to their high purity. Usually, a sintered sheet having a high thermal conductivity of 120 W/m- or more, preferably 140 W/m- or more can be obtained. Furthermore, depending on the firing conditions, it is possible to obtain a sintered sheet with extremely excellent thermal conductivity of 160 W/m- or more. Furthermore, an aluminum nitride sintered sheet having excellent translucency can also be produced.

Therefore, the aluminum nitride sintered sheet obtained according to the present invention is an industrially extremely useful material as a heat dissipation board for electronic equipment, an electronic circuit board, a heat dissipation material, and an insulating material.

EXAMPLES In order to explain the present invention more specifically, the present invention will be described below with reference to Examples, but the present invention is not limited to these Examples.

Example 1 Aluminum nitride powder having the composition shown in Table 1 containing 80% by volume of particles with an average particle size of 2.12 μm and 3 μm or less,
Y2O3 powder as sintering aid, CaF2 powder as alkaline earth metal halide, and molecular weight 30 as binder.
An aluminum nitride green sheet and an aluminum nitride sintered sheet were produced using polyvinyl butyral of .000 to 34,000 in the following manner.

(i) Compounded aluminum nitride powder 100 parts by weight Y2O3
Powder 0.7〃CaFt powder
1.3 Polyvinyl butyral
9.0〃? Dioctyl phthylate 5.0 Solhitane trioleate 1.2 Table 1 Aluminum nitride powder analysis value/IN content
98.0% Element Content Mg <5 (ppn+)Cr
ku10 (〃 ) Si 46 (” ) Zn
<lO(〃) Fe 14 (〃) Cu 5 (〃
)Mn〈5(〃)Ni 18(〃)Ti〈5(〃)Co〈5(〃)A1
64.8 (wt%)N 33.
5('') 0 1.0(〃) c O,04('') (ii) Half the amount of solvent (37,
5 parts by weight) and add aluminum nitride powder, Y while stirring.
After the entire amounts of 2O3 powder, caFz powder, and sorbitan trioleate were added, polyvinyl butyral was gradually added to dissolve the entire amount. Next, the entire amount of dioctyl phthalate was added, and the remaining amount of the solvent (37.5 parts by weight) was added, and stirring was continued for 1 hour to disperse or dissolve the ingredients to form a slurry in advance.

In a nylon pot with an internal volume of 101, a steel ball coated with nylon and having a diameter of 20III11 is placed in a nylon pot with an internal volume of about 5
Then, the slurry obtained above was added and mixed in a boiler for 36 hours at a rotation speed of 35 rpm. The resulting slurry was like a white paint with a viscosity of 23,000 cps.

(iii) Defoaming and desolvation Transfer the slurry obtained by the above mixing to a vacuum container with an internal volume of 4β equipped with a stirrer, and gradually increase the pressure from 1 atm to 30 to 4 QT while stirring.
The pressure was reduced to orr to remove air bubbles mixed into the slurry during the mixing (defoaming).

Next, while stirring and evacuating the inside of the vacuum container, the mixture was heated for 20~
A portion of the solvent was removed by evaporation while maintaining the temperature at 40 Torr (desolvation).

The amount of solvent removed in this desolvation operation was 20 parts by weight based on 100 parts by weight of the aluminum nitride powder. As a result, a white viscous slurry with a viscosity of 20.0OOcps was obtained.

(iv) Molding Using a doctor blade type sheet molding machine, the resulting slurry is poured into a sheet onto a polyester film whose surface has been coated with silicone resin and subjected to mold release treatment, and then the sheet is kept at room temperature. 30m1n, then 50℃
After further drying by evaporating 30 ml of the solvent at 80° C., the sheet-like material was peeled from the polyester film to produce an aluminum nitride green sheet having a width of about 250 fi and a thickness of about 1 crane. This aluminum nitride green sheet has a white, glossy appearance, and is flexible and strong against bending. A test piece was punched out from an aluminum nitride green sheet using a die and a punching machine, and a tensile test using an autograph was performed, and the tensile strength was 25 kg/d and the elongation rate was 0.
．． It was 4. Further, the density was 2.16 g/cm3.

(v) Degrease and sinter the above aluminum nitride green sheet 50m x 50
The polyvinyl butyral, dioctyl phthalate, and sorbitan trioleate were burned and decomposed by punching them into square plates of 500 m in diameter and heating them in an electric furnace at 650°C for 3 hours in an air atmosphere of 1 atm to burn and decompose the polyvinyl butyral, dioctyl phthalate, and sorbitan trioleate. A square plate was obtained (degreased).

This square plate was set in a graphite-type dish whose inner wall was coated with boron nitride, and the temperature was raised to 1.100°C in 2 hours in nitrogen at 1 atm, then 15°C/100°C from 100°C to 1,800°C.
The temperature was raised at a temperature increase rate of min and held at 1.800°C for 10 hours (sintering). The obtained aluminum nitride sintered sheet had a shape of 41nx41tm and a thickness of 0.85m, and a density of 3.26g/cm3. The thermal conductivity of this sintered sheet was measured by a non-contact method using an In-:Sb infrared sensor using a laser flash method thermal constant measuring device (PS-7) manufactured by Rigaku Denki, and it was found to be 190 W/m -k.
obtained the value of

The bending strength of this sintered sheet is 43+r/m'',
The oxygen content measured by activation analysis was 0.10% by weight.

Furthermore, the sintered sheet is melted with alkali to remove Ca,
Y, Mg, Cr, Si, Zn, f? e.

When the respective contents of Cu, Mn, Ni, Ti, and Co were measured by inductively coupled plasma emission spectrometry, they were converted into concentrations in the sintered sheet, Ca=890 ppm, -Y=
320ppm SMg<5ppm, Cr<10p
p.m.

Si=142ppm, Zn<10ppm SFe<IQp
pm% Cu<10ppm, Mn<5pp
m, Ni=15ppm, Ti=25ppm, Co
<10 ppm, and Ca and Y added as sintering aids
The total content of 10 elements excluding 1 was 242 ppm or less.

Another sintered sheet sintered in the same manner was ground to a thickness of 0.5 tm, and both sides were polished to a mirror finish. When the light transmittance was measured, the linear transmittance was 36% for a wavelength of 5.5 μm. was gotten.

Example 2 Aluminum nitride powder with an average particle size of 1.42 μm and 3 μm or less accounted for 87% by volume and the composition shown in Table 2, Y2O at various addition rates shown in Table 3 as a sintering aid, powder, and CaF, powder, as alkaline earth metal halide
Further, an aluminum nitride green sheet and an aluminum nitride sintered sheet were produced as follows using polyvinyl butyral having a molecular weight of 30.000 to 34.000 as a binder. The results are shown in Table 3. Note that IVll14 is a comparative example.

(i) Compounded aluminum nitride powder 100 parts by weight Y2O3
Powder Table 3 CaFt powder
Table 3 Polyvinyl butyral 1
2.0 parts by weight Dibutyl phthalate 5.0' Glycerin trioleate 1.0 parts by weight Table 2
Aluminum nitride powder analysis value AIN content
98.0% Element content Mg <5 (ppm) Cr
<10 (〃) Sl 38 (〃) Zn <10 (〃) Fe 15 (〃) Cu <5 (〃) Mn <5 (//) Ni <10 (〃) Ti < 5
('')Co〈5 (〃)Aff 64.8 (wt%)N
33.5 (〃) 0 1.0 (〃) CO,04 (〃) (ii) In a nylon pot with a mixing internal volume of 102, steel balls with a diameter of 20 mm coated with nylon are added to about 50% of the internal volume of the pot. , then add aluminum nitride powder, Y2O
3 powder, CaF2 powder, and glycerin trioleate, a portion of the solvent (60 parts by weight) was further added, and the mixture was mixed in a boiler for 24 hours at a rotation speed of 35 rpm. Then, add the entire amount of polyvinyl butyral and dibutyl phthalate to the same pot, and add the remaining amount of solvent (20% by weight).
was added and mixed in a boiler mill for 24 hours. The obtained slurry had a viscosity of 2.2000 to 2.600 cps and was like white paint.

(iii) Defoaming and desolvation It was carried out in the same manner as in Example 1. The viscosity of the resulting slurry ranged from 21,000 to 25.0 OO cps.

(iv) Molding An aluminum nitride green sheet was obtained in the same manner as in Example 1. The density of the aluminum nitride green sheets ranged from 1.92 to 2.06 g/c11'', and the tensile strength ranged from 27 to 30 kg/cd.

(v) Degreasing and sintering 50% of the aluminum nitride green sheet obtained above was
A square plate of nX5Q+n was punched out, and this square plate was placed in a graphite-type dish whose inner wall was coated with boron nitride and set in an electric furnace. 0.1~Q, 1 from room temperature under reduced pressure of 5 Torr
, and degreasing was carried out by raising the temperature to 100°C at a rate of 2°C/min.

Thereafter, the temperature was raised from 1,100°C to 1.800°C in the same electric furnace at the temperature increase rate shown in Table 3, and maintained at 1.800°C for the time shown in Table 3. The obtained aluminum nitride sintered sheet had a shape of 4.1 square meters and a thickness of about 0.85 m. Table 3 shows the physical properties of the sintered sheet.

Example 3 The same aluminum nitride powder as used in Example 2, various lanthanum group metal compounds and alkaline earth metal halides shown in Table 4 as sintering aids, and a binder with a molecular weight of 50.000 An aluminum nitride green sheet and an aluminum nitride sintered sheet were produced as follows using a methacrylic acid ester copolymer (ethyl methacrylate/methyl acrylate = 72/28) of ~90,000.

(1) Compounded aluminum nitride powder 100 parts by weight Compounds of lanthanum group metals (Showed in Table 4) Alkaline earth metal halides (Showed in Table 4) Procedural amendment dated December 1985 Michi Uga, Commissioner of the Patent Office 1. Indication of the case Japanese Patent Application No. 189474/1989 2. Name of the invention Aluminum nitride composition 3. Relationship with the case by the person making the amendment Patent applicant address 1-1 Mikage-cho, Tokuyama City, Yamaguchi Prefecture "Detailed Description of the Invention" Column 5, Contents of Amendment (1) On page 17, line 5 of the specification, r23,0OOJ is corrected to r2.300J.

(3) Page 34, line 12 Correct r2.2000J to r2,200J.

(4) Page 35, line 12 Correct "4.1 Seal Tomb Angle" to r 41 x * angle.

(5) In the 8th line from the bottom of No. 37, “Toluene (60% by weight)” is changed to “Toluene (50% by weight)”
)”.

(6) 5th line from the bottom of No. 37, r(iii) Defoaming and solvent removal", then r(iv) Molding"
Insert.

(7) 3rd line from the bottom of No. 37 Correct r(iv)J to r(v)J.

that's all

Claims (6)

[Claims] (1) (i) Aluminum nitride powder, (ii) A binder made of an organic polymer compound that decomposes at a temperature of 1400°C or lower, (iii) At least one metal selected from the group consisting of yttrium and lanthanum group metals. and (iv) an alkaline earth metal halide; the binder is 0.1 to 30 parts by weight per 100 parts by weight of aluminum nitride powder; 0.01 to 5 parts by weight per 100 parts by weight of aluminum powder, and the alkaline earth metal halide is 1 part by weight of aluminum nitride powder.
An aluminum nitride composition containing 0.01 to 10 parts by weight based on 0.00 parts by weight. (2) Aluminum nitride powder has an oxygen content of 3.0% by weight
The aluminum nitride composition according to claim (1), which is as follows. (3) The aluminum nitride composition according to claim (1), wherein the aluminum nitride powder has an average particle size of 5 μm or less. (4) The aluminum nitride composition according to claim (1), wherein the aluminum nitride powder contains 0.5% by weight or less of a metal compound as an impurity. (5) The aluminum nitride composition according to claim (1), wherein the binder is an oxygen-containing organic polymer. (6) The molecular weight of the oxygen-containing organic polymer is 3000 to 1,0
00,000, the aluminum nitride composition according to claim (5).