JP2003146760A - Aluminum nitride sintered compact and method of producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aluminum nitride sintered compact having excellent mechanical strength, resistance to thermal shock, corrosion resistance to gaseous halogens and a volume resistivity hardly depending on temperature. SOLUTION: In the aluminum nitride sintered compact, crystals of Al5 O6 N and/or Al9 O3 N7 are dispersed in the matrix, and magnesium is contained in an amount of 0.1 to 2 wt.%. A method of producing the aluminum nitride sintered compact comprises mixing a magnesium component and Al5 O6 N and/or Al9 O3 N7 components with aluminum nitride powder and firing resulting mixture at 1,750 to 1,950 deg.C for at least 15 h.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum nitride sintered body having a volume resistivity with small temperature dependence in a wide temperature range from room temperature (25 ° C.) to high temperature, for example, 800 ° C.

[0002]

2. Description of the Related Art Currently, an electrostatic chuck or the like is used to adsorb and hold a semiconductor wafer in processes such as etching, film formation and metallization. Since halogen-based corrosive gases are used in these processes and they are used at high temperatures, materials having excellent corrosion resistance and heat resistance are required. On the other hand, aluminum nitride is considered to be suitable as a semiconductor manufacturing component such as an electrostatic chuck because it has high thermal conductivity, excellent mechanical strength and thermal shock resistance, and excellent corrosion resistance to halogen gas. To be

When the aluminum nitride sintered body is used in the above electrostatic chuck, the volume resistivity is 1 × 10 ¹⁴ to 1 × 1.
Large suction force can be obtained in the range of 0 ⁸ Ω · cm.

However, the volume resistivity of the aluminum nitride sintered body is highly dependent on temperature, for example, 10 ¹⁵ Ω · c at room temperature.
Higher than m, volume resistivity decreases with increasing temperature, 8
Since it becomes 10 ⁶ Ω · cm or less at 00 ° C., it is not possible to stably obtain a high adsorption force in a wide temperature range, and the operating temperature is limited to an intermediate temperature range of about 150 to 500 ° C. Therefore, there has been a need for an aluminum nitride sintered body that can stably obtain a high adsorption force from room temperature to a high temperature range.

Therefore, as an attempt to reduce the temperature dependence of the volume resistivity of the aluminum nitride sintered body, for example, in JP-A-11-100270, the compounding amount of the rare earth element compound is adjusted to control the pressure during sintering. By increasing the amount, the amount of residual oxygen in the aluminum nitride particles can be controlled.
Volume resistivity at 0 to 500 ° C. is 1 × 10 ¹⁴ to 1 ×
A sintered body having a resistance of 10 ⁷ Ω · cm has been proposed.

Further, according to Japanese Patent Laid-Open No. 2000-143349, by firing TiN and CeAlO _{3 in} aluminum nitride, the volume resistivity at 0 to 50 ° C. is 1 × 10 ⁸ to 1 × 10 ¹² Ω · cm. A union is proposed.

However, in recent years, due to the demand for further miniaturization of semiconductor design rules and improvement of productivity, the processing temperature of semiconductor wafers tends to be higher and higher, and accordingly, the static temperature with a high volume resistivity at a higher temperature. A substrate for an electric chuck has come to be desired, and ideally, a substrate for an electrostatic chuck having a volume resistivity of, for example, 1 × 10 ¹⁴ to 1 × 10 ⁸ Ω · cm even in a region exceeding room temperature to 800 ° C. It has come to be desired.

However, the above-mentioned Japanese Unexamined Patent Publication No. 11-100270.
The volume resistivity of the sintered body described in Japanese Patent Publication exceeds 10 ¹⁴ Ω · cm at room temperature and increases, and the volume resistivity decreases to about 10 ⁶ Ω · cm near 800 ° C. Furthermore, because pressure sintering such as hot pressing is a necessary condition,
There are problems such as a larger size of the apparatus and a lower cost of molding the furnace into the furnace, and higher firing costs, as compared with atmospheric pressure sintering.

Further, the sintered body containing TiN and CeAlO ₃ described in Japanese Patent Laid-Open No. 2000-143349 is used as a substrate of an electrostatic chuck from room temperature to 20 at most.
There is a problem that a stable adsorption force can be obtained only in the temperature range of 0 ° C. and that it cannot be used in the high temperature range. Furthermore, T
Since iN is a transition metal, it is not always suitable in the semiconductor manufacturing process.

Further, as a method for improving the decrease in volume resistivity on the high temperature side, Japanese Patent Laid-Open No. 2000-44345 discloses that the volume resistivity at 700 ° C. is 1 × 10 ⁷ Ω · cm.
As described above, it has been proposed to add magnesium to the aluminum nitride polycrystal as an aluminum nitride sintered body having a thermal conductivity of 80 w / m · K or less. However, even in this method, the volume resistivity becomes 1 × 10 ⁸ Ω · cm or more only up to about 600 ° C.

Therefore, the present inventors have conducted various studies to obtain an aluminum nitride sintered body having a volume resistivity at 800 ° C. of 1 × 10 ⁸ Ω · cm or more.
It has already been found that a sintered body made of a rare earth compound and MgAl ₂ O ₄ has a thermal conductivity of 75 w / m · K or more and a volume resistivity at 800 ° C. of 1 × 10 ⁸ Ω · cm or more. Proposed as No. 2001-16074. This aluminum nitride sintered body has sufficient volume resistance characteristics at high temperature to satisfy desired physical properties,
At room temperature (25 ° C), the volume resistivity is rather 1 x 10
There is a tendency for it to exceed ¹⁴ Ω · cm and become too large, and there is room for improving the volume resistivity on the low temperature side from the viewpoint of utilization.

Aluminum nitride in a temperature range near room temperature
Physical properties, especially when used as an electrostatic chuck member
Possibility of exhibiting suction power that can handle large wafers
AlON phase as an aluminum nitride sintered body with high performance
And an aluminum nitride sintered body containing boron,
It is proposed in JP-A-11-317441. This
The aluminum nitride-based sintered body of
When expressed as elemental content, the maximum electrostatic absorption around 5% by weight
It is recognized that it shows a firmness. However, on the high temperature side,
Since the original performance of aluminum fluoride is maintained,
Resistance rate is 1 × 10 ⁸Ω · cm or less. Furthermore, the publication
The improvement of volume resistivity is completely described in
The temperature dependence cannot be predicted.

[0013]

Therefore, the present inventors have found that
High thermal conductivity, excellent corrosion resistance to halogen-based corrosive gases, and 1 x 10 in a wide temperature range from room temperature to 800 ° C
Research was conducted for the purpose of developing an aluminum nitride sintered body having a volume resistivity in the range of ¹⁴ to 1 × 10 ⁸ Ω · cm.

As a result, in the aluminum nitride sintered body, A
The crystals of l ₅ O ₆ N and / or Al ₉ O ₃ N ₇ dispersed therein and containing a magnesium component in a specific amount,
1 × 10 ⁸ Ω at 800 ° C due to the synergistic action of both compounding agents
It has a volume resistivity of 1 cm or more and is 1 × 1 even at room temperature.
It was found that the volume resistivity was 0 ¹⁴ Ω · cm or less. Such a phenomenon was truly surprising.

[0015]

Therefore, as a result of further research based on the above findings, the present inventors have found that the high thermal conductivity is
The present invention has been completed by finding that an aluminum nitride sintered body having a volume resistivity with little temperature dependency and also having a high corrosion resistance to a halogen-based corrosive gas and further excellent in mass productivity can be obtained. Came to do.

That is, according to the present invention, Al ₅ O ₆ N and / or Al _{9 is} contained in the aluminum nitride sintered body matrix.
The aluminum nitride sintered body is characterized in that a crystal phase of O ₃ N ₇ is dispersed and contains magnesium in an amount of 0.1 to 2% by weight based on the total weight.

In the aluminum nitride sintered body of the present invention,
Indicates that the aluminum nitride polycrystalline particles are adjacent to each other and
Depending on the combination, a compound derived from impurities or a sintering aid may be present in the grain boundary.
X between the matrices that formed the continuous phase interspersed with the
Al by line diffraction₅O₆Peak derived from N crystal (2θ
= 31.0 to 32.0 °) and / or Al₉O_ThreeN ₇
Crystal-derived peak (2θ = 70.5 to 71.5 °)
A substance having₅O₆N crystal and
And Al₉O_ThreeN₇Crystals)
Existence is not observed by scanning electron microscope (SEM)
Where can I find out?

The presence of the magnesium component is indispensable for the aluminum nitride sintered body of the present invention. As will be apparent from FIG. 1 described later, the magnesium component must be 0.1 to 2% by weight based on the total weight of magnesium atoms, and the magnesium component is present in a dispersed state in the aluminum nitride sintered body. It can be confirmed by fluorescent X-ray measurement (XRF).

According to the present invention, Al ₅ O ₆ N crystals and / or Al ₉ O are contained in the aluminum nitride matrix.
If the crystals of ₃ N ₇ are dispersed,
Although not particularly limited, the peak intensity area of the aluminum nitride crystal (2θ = 4 is obtained from the peak intensity area of X-ray diffraction).
9.5 to 50.5 °) peak intensity area of Al ₅ O ₆ N crystal (2θ = 31.0 to 32.0 °) and Al
₉ O ₃ N ₇ crystal peak intensity area (2θ = 70.5 to 7)
It is particularly preferred that the sum of the ratios (1.5 °) is 0.02-0.60 with respect to 1 aluminum nitride.

One of the features of the aluminum nitride sintered body of the present invention is that the volume resistivity is 1 × 10 ¹⁴ to 1 × 10 ⁸ Ω · cm in a wide temperature range from room temperature to 800 ° C.

Further, another feature of the aluminum nitride sintered body of the present invention is that it has a high thermal conductivity of 60 W / m · K or more, further 80 W / m · K, especially 90 W / m · K or more. Can be

Aluminum nitride sintering of the present invention as described above
The method for manufacturing the body is not particularly limited, but in general, aluminum nitride is used.
Magnesium component to 100 parts by weight of minium powder
1 to 4.2 parts by weight as magnesium oxide, Al₅O₆
N and / or Al₉O_ThreeN ₇Aluminum oxide
And sinter a mixture containing 2.5-9 parts by weight as
It is obtained by Furthermore, the above magnesium component
Magnesium oxide as Al₅O₆N and / or
Al₉O_ThreeN₇Aluminum oxide as a component
Sinter at 1750 to 1950 ° C. for 15 hours or more,
Alternatively, magnesium component and Al₅O₆N and /
Or Al₉O_ThreeN₇MgAl as a component _TwoO_FourUsing 1
By firing at 750 to 1950 ° C for 15 hours or more
The sintered body of the present invention can be obtained.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
One of the features of the present invention is that aluminum nitride is the main crystal, and the crystal phase of Al ₅ O ₆ N and / or Al ₉ O ₃ N ₇ is contained therein, and magnesium is contained, The volume resistivity in the temperature range from room temperature to 800 ° C. is 1 × 10 ¹⁴ to 1 × 10 ⁸ Ω · cm. Another feature is that a sintered body having a high thermal conductivity of 60 W / m · K or more can be obtained.

In the present invention, the crystal phase of Al ₅ O ₆ N and / or Al ₉ O ₃ N ₇ contained in the aluminum nitride sintered body is the peak intensity area (2) of the aluminum nitride crystal.
The peak intensity area (2θ = 31.0-32.0 °) of the Al ₅ O ₆ N crystal and the peak intensity area (2θ = 70) of the Al ₉ O ₃ N ₇ crystal with respect to θ = 49.5 to 50.5 °). ．
It is preferable that the sum of the ratio (5 to 71.5 °) is in the range of 0.02 to 0.60, and further preferably in the range of 0.05 to 0.30. When the ratio is larger than 0.60, the thermal conductivity tends to be small, and in some cases, it is reduced to 60 W / m · K or less. Further, when the ratio is less than 0.02, the volume resistivity at room temperature becomes large, and deviates from 1 × 10 ¹⁴ Ω · cm in some cases. FIG. 2 is a diagram showing X-ray diffraction peaks in one example of the present invention (however, the upper part of the peak of aluminum nitride is cut). The ratio of the peak intensity area of the Al ₅ O ₆ N crystal and / or the peak intensity area of the Al ₉ O ₃ N ₇ crystal to the peak intensity area of the aluminum nitride crystal is CuK.
It can be determined by X-ray diffraction using α rays.

Al ₅ O ₆ N and / or Al ₉ O
Magnesium is added to the aluminum nitride sintered body having a crystal phase of ₃ N ₇ in an amount of 0.1 to 2% by weight, preferably 0.1% by weight based on the total weight.
It is necessary to contain 5 to 1% by weight.

That is, the content of magnesium has a great influence on the volume resistivity particularly in the high temperature region. Figure 1 shows Al
₅ O ₆ N and / or Al ₉ O ₃ N ₇ in the presence of 0.5 to 3.0 with respect to aluminum nitride and the amount of magnesium present and the volume of the aluminum nitride sintered body at room temperature, 500 ° C. and 800 ° C. It is a figure which shows the relationship of a resistivity, and there is a peak of effect about 0.5-1 weight% of magnesium, and after that, an effect declines gradually and it is about 2 weight%.
And the volume resistivity at 800 ° C. is 1 × 10 ⁸ Ω
・ Decrease to below cm.

Therefore, when the magnesium content deviates from the above range, it is generally difficult for the volume resistivity at 800 ° C. to become 1 × 10 ⁸ Ω · cm or more.

The average grain size of the crystal grain size of aluminum nitride forming the matrix of the aluminum nitride sintered body of the present invention is preferably 0.5 to 50 μm, more preferably 1 to 20 μm. If the average particle size is too small, the work piece is likely to be damaged when the base material is machined into a desired shape, and the product yield is reduced. Further, if the average particle size is too large, it becomes difficult to obtain strength as a base material.

The method for producing the aluminum nitride sintered body of the present invention is not particularly limited as long as it can obtain the one having the properties specified in the present invention, but the present invention is preferably used in the following method. The specified properties can be achieved.

In the present invention, the aluminum nitride powder used may be any known aluminum oxide reduction nitride powder, direct nitriding powder of metallic aluminum or the like without any problem, but in consideration of obtaining a dense sintered body, The average particle size is preferably 5 μm or less, and further 3 μm
The following is preferable. Further, the metal impurities other than aluminum and magnesium are preferably 1000 ppm or less.

In the present invention, Al ₅ O ₆ N and / or Al ₉ O ₃ N ₇ may be separately synthesized and mixed with aluminum nitride powder, but the above-mentioned crystals are formed when the aluminum nitride powder is sintered. The most advantageous method is to mix with aluminum nitride powder as a possible component and form the crystals during sintering. In this case, by using aluminum oxide, it is possible to react with the aluminum nitride of the matrix to form crystals of Al ₅ O ₆ N and / or Al ₉ O ₃ N ₇ . Of course, an aluminum compound such as aluminum nitrate or aluminum carbonate that can be easily converted into an oxide at a temperature lower than the sintering temperature of aluminum nitride can be used as well.

Among them, MgAl ₂ O _4, which is a magnesium composite oxide, is a particularly preferable substance because it can simultaneously introduce a magnesium component.

In the present invention, when MgAl ₂ O ₄ is used, its characteristics are not limited, but in order to obtain a sintered body having a high resistivity in the high temperature region, the purity is 99.9% or more and the average particle size is It is desirable to use a fine powder of 2 μm or less, particularly 0.5 μm or less.

In the present invention, the amount of Al ₅ O ₆ N and / or Al ₉ O ₃ N ₇ present in aluminum nitride is such that the aluminum content in the compound is usually aluminum oxide based on 100 parts by weight of aluminum nitride. It is preferable to use 2.5 to 9 parts by weight in the ratio obtained.

Next, magnesium to be used in the present invention is another magnesium oxide compounded as the above composite oxide, or
It is also possible to use a compound capable of forming magnesium oxide under the sintering conditions of aluminum nitride, such as magnesium nitrate or magnesium carbonate. It is preferable that these compounds also have a high purity, and normally, a purity of 99% or more and an average particle size of 1 μm or less is preferably used in an amount of 1 to 4.2 parts by weight in a ratio determined as magnesium oxide.

The method for producing a sintered body according to the present invention is a conventional method
It is not particularly different from the method of manufacturing a luminium sintered body.
For aluminum nitride, rare earth compounds are used as sintering aids.
10 parts by weight or less, preferably about 0.5 to 7 parts by weight
It's okay to get good results often
It The type of rare earth compound is not particularly limited.
For example, Y_TwoO_Three, La_TwoO_Three, CeO_Two, Ho_Two
O_Three, Yb_TwoO_Three, Gd _TwoO_Two, Nd_TwoO_Three, Sm_TwoO
_Three, Dy_TwoO_ThreeAmong them, among them, Y _TwoO_Three
Is preferred.

In the present invention, the method of mixing various compound powders such as MgAl ₂ O ₄ mixed with the aluminum nitride powder is not particularly limited, and a known method of mixing aluminum nitride powder with a powder such as a sintering aid is adopted. You can Examples thereof include a method of obtaining a mixture (mixed powder) by dry mixing, a method of wet mixing with an organic solvent such as ethanol using a ball mill, etc. to obtain a slurry of the mixture. The slurry is sufficiently dried. Solvent removed mixture (mixed powder)
To get

In the present invention, as a method of obtaining an aluminum nitride sintered body, a green body may be prepared in advance before firing the mixture. A known method can be applied to produce a green body. For example,
A method of molding the mixture (mixed powder) with a uniaxial press, a hydrostatic pressure press (CIP) or the like to obtain a green body, or a method of adding an organic binder or the like to the mixed powder, pressing a mold, or performing sheet molding to obtain a green body. And a method of casting the mixture slurry.

Known organic binders can be used without particular limitation. Specifically, polyvinyl butyral, ethyl celluloses, acrylic resins and the like can be used, and among them, poly-n-butyl methacrylate and polyvinyl butyral are preferable because of excellent moldability of the green body.

The amount of the organic binder added to the mixed powder is 2 to 15 parts by weight per 100 parts by weight of aluminum nitride in the case of obtaining a press-molded body, and 5 to 15 parts by weight in the case of obtaining a sheet body. It is preferably adopted.

As a method of using the above-mentioned organic binder, an organic solvent such as alcohols and toluene, a dispersant such as a glycerin compound, and a plasticizer such as phthalic acid are added to the mixture and the organic binder as needed, and a ball mill is sufficient. It is common to mix the mixture into a slurry to make it into granules by a spray drying method or the like, and then use a die press to form a block-shaped green body or a doctor blade method to form a sheet-shaped green body. .

The green body using the above organic binder is usually degreased before firing to obtain a degreased body.
The degreasing is carried out by heat treatment in an oxidizing gas such as oxygen or air, a reducing gas such as hydrogen, an inert gas such as argon or nitrogen, carbon dioxide and a mixed gas thereof or a humidified gas atmosphere in which steam is mixed. The method is generally used. The degreasing temperature is in the range of 250 to 1200 ° C., and the holding time is in the range of 1 to 1000 minutes, and may be appropriately selected according to the blending ratio of the organic binder and the degreasing method.

In the present invention, the green body not containing the organic binder or the degreased body obtained by further degreasing the green body containing the organic binder is used in a non-oxidizing atmosphere.
Baking is performed at a temperature of 750 ° C. or higher for 15 hours or longer, preferably 20 hours or longer. However, there is no technical merit even if the firing is performed for a too long time, rather, since the aluminum nitride crystal grains grow and the strength decreases, firing is generally performed at 70%.
Less than an hour is enough.

The firing temperature should be 1750 to 1950 ° C, the firing temperature is 1750 ° C or lower, or the firing time is 1
If it deviates from the above range for either less than 5 hours, Al ₅ O ₆ N and / or Al ₉ O in aluminum nitride.
_This is because the case where the ₃ N ₇ crystal phase is generated is not sufficient, the volume resistivity at room temperature is less than 1 × 10 ⁸ Ω · cm, and the aluminum nitride sintered body of the present invention cannot be obtained.

As the non-oxidizing atmosphere, for example, an atmosphere of a single gas such as nitrogen, argon, helium, hydrogen or a mixed gas, or a vacuum atmosphere is used.

Sintering is carried out under normal pressure firing, hot pressing (H
P) and hot isostatic pressing (HIP).

The normal pressure firing is usually carried out by placing the green body or degreased body in a firing vessel. As the baking container, a known container used for baking aluminum nitride can be used. A specific example is a box-shaped closed container made of aluminum nitride or boron nitride.

Further, between the green body or degreased body and the firing container, a generally used spread powder may be interposed to prevent fusion due to firing. Examples of the spread powder include boron nitride and the like.

The HP may be a known method. Normal,
A jig made of carbon is used, and the mixed powder, the green body or the degreased body is housed in the jig. It is effective to prevent fusion between the jig and the object to be fired by applying boron nitride or disposing a carbon sheet or powder on the surface of the jig that comes into contact with the object to be fired. The HP pressure is within a known pressure range, and is, for example, 5 to 50 MPa.

As described above, the aluminum nitride sintered body of the present invention has both high thermal conductivity and small volume resistivity with low temperature dependence. In addition, the bending strength, dielectric constant, other physical properties of the sintered body and the appearance of the sintered body are also good.

[0051]

EXAMPLES Examples will be shown below for specifically explaining the method of the present invention, but the present invention is not limited to these examples. 1) Measurement of average particle diameter of aluminum nitride sintered body 300 or more aluminum nitride particles exposed at the fracture surface of the sintered body were determined by a mode method.

2) Measurement of density of aluminum nitride sintered body It was measured by the Archimedes method and the relative density was calculated.

3) X-ray diffraction (XRD) was performed on the ground surface of the crystal phase sintered body constituting the aluminum nitride sintered body.

4) Measurement of magnesium contained in aluminum nitride sintered body Fluorescent X-ray measurement (XRF) was performed on the ground surface of the sintered body.

5) Measurement of volume resistivity of aluminum nitride sintered body In high purity nitrogen having a purity of 99.999% or more, JI
It measured based on S2141.

6) Measurement of thermal conductivity of aluminum nitride sintered body Using a thermal constant measuring device PS-7 manufactured by Rigaku Denki Co., Ltd.
It was measured by the laser flash method. The thickness was corrected by the calibration curve.

Examples 1 to 8 Aluminum nitride powder having an average particle size of 1.5 μm and an oxygen concentration of 0.8 wt%, and a purity of 99.99 as a rare earth oxide.
% Or more and a specific surface area of 12.5 m ² / g of yttrium oxide powder, and a purity of 99.9% or more and an average particle diameter of 0.
39 μm of MgAl ₂ O ₄ powder was added in the compounding amount shown in Table 1. Next, ethanol was added as a solvent, mixed by a ball mill and dried to obtain a mixed powder, which was CIP molded to obtain a green body having a diameter of 38 mm and a thickness of 4 mm.

The green body thus obtained was placed in a baking container made of aluminum nitride and kept in a nitrogen atmosphere at a temperature of 1780 ° C. for a holding time of 20 hours (in Example 6, 35 hours,
Example 7 was subjected to normal pressure firing for 50 hours) to obtain a relative density of 98.
% Or more dense aluminum nitride sintered body was obtained. Table 1 shows the blending amount of each substance, firing conditions, and the like.

X-ray diffraction of the sintered body was performed. Which
The aluminum nitride phase is mainly contained in the aluminum nitride sintered body.
Impurity Oxygen and Yttrium Oxide in Aluminum Nitride as Phase
YA, which is a complex oxide phase formed by the reaction of aluminum during firing
G (3Y_TwoO_Three・ 5Al_TwoO _Three) Phase and Al₅O₆N phase
And / or Al₉O_ThreeN₇There was a phase.

Further, the amount of magnesium contained in the sintered body was quantified by fluorescent X-ray measurement. Each of the sintered bodies contained a magnesium component.

Table 2 shows the relative density, volume resistivity and thermal conductivity of the sintered body. The sintered bodies of Examples 1 to 8 satisfied the aluminum nitride sintered body of the present invention.

Examples 9 and 10 Aluminum nitride powder and yttrium oxide powder of Example 1
Powder and MgAl_TwoO _FourMix the powders in the amounts shown in Table 1.
did. Then add ethanol as a solvent and
Mixed and dried to obtain a mixed powder. This mixed powder is black
Fill a lead-made HP jig at 1830 ° C in a nitrogen atmosphere.
Hold for 20 hours, perform HP at a pressure of 20 MPa, and
Diameter 40mm, thickness 3.5mm, relative density 99% or more
A dense sintered body was obtained.

When X-ray diffraction of the sintered body was performed,
Aluminum oxide phase as the main phase, Al ₅O₆N phase and A
l₉O_ThreeN₇There was a phase.

Further, when the amount of magnesium contained in the sintered body was measured by fluorescent X-ray measurement, it was found to contain a magnesium component.

Table 1 shows the manufacturing conditions and the like of the sintered body, and Table 2 shows the relative density, volume resistivity and thermal conductivity. The obtained sintered body satisfied the aluminum nitride sintered body of the present invention.

Example 11 The aluminum nitride powder, MgAl ₂ O ₄ powder of Example 1 and a purity of 99.99% or more and an average particle size of 1.33 μm.
The aluminum oxide of was mixed in the compounding amounts shown in Table 1, and the same operation as in Example 9 was performed.

When X-ray diffraction of the sintered body was performed,
Aluminum oxide phase as the main phase, Al ₅O₆N phase and A
l₉O_ThreeN₇There was a phase.

Further, when the amount of magnesium contained in the sintered body was determined by fluorescent X-ray measurement, it was found to contain 0.16% by weight of magnesium component.

Table 1 shows the production conditions of the sintered body and Table 2 shows the physical properties thereof. The obtained sintered body satisfied the aluminum nitride sintered body of the present invention.

Example 12 The aluminum nitride powder and MgAl ₂ O ₄ powder of Example 1 were mixed in the compounding amounts shown in Table 1, and the same operation as in Example 9 was performed.

When X-ray diffraction of the sintered body was performed,
Aluminum oxide phase as the main phase, Al ₅O₆N phase exists
It was

Further, the amount of magnesium contained in the sintered body was determined by fluorescent X-ray measurement and found to contain 1.07% by weight of magnesium component.

Table 1 shows the production conditions and the like of the sintered body, and Table 2 shows the physical properties thereof. The obtained sintered body satisfied the aluminum nitride sintered body of the present invention.

Examples 13 and 14 Mg was added to the aluminum nitride powder of Example 1 as a sintering aid.
The same operation as in Example 1 except that magnesium oxide and aluminum oxide having a purity of 99.9% or more and an average particle diameter of 0.2 μm were mixed in the compounding amounts shown in Table 1 instead of the Al ₂ O ₄ powder. I went. The physical properties are shown in Table 2. The obtained sintered body satisfied the aluminum nitride sintered body of the present invention.

Comparative Example 1 Yttrium oxide as a sintering aid was mixed with the aluminum nitride powder of Example 1 and the same operation as in Example 1 was performed. When X-ray diffraction was performed, aluminum nitride phase, Y
There was an AG phase and an AlYO ₃ phase. In addition, Al
The presence of ₅ O ₆ N phase and Al ₉ O ₃ N ₇ phase could not be confirmed. Tables 1 and 2 show the production conditions and the physical properties of the sintered body.

Comparative Example 2 The same operation as in Example 1 was carried out except that the holding time during firing was 3 hours. When X-ray diffraction was performed, an aluminum nitride phase, a YAG phase, and a MgAl ₂ O ₄ phase were present. Tables 1 and 2 show the production conditions and the physical properties of the sintered body.

Comparative Examples 3 and 4 The same operation as in Example 1 was carried out except that the magnesium content in the sintered body was out of the range of 0.1 to 2.0% by weight. Tables 1 and 2 show the production conditions and the physical properties of the sintered body.

Comparative Example 5 The aluminum nitride powder of Example 1 was mixed with yttrium oxide and aluminum oxide as a sintering aid, and the same operation as in Example 1 was performed. When X-ray diffraction was performed, an aluminum nitride phase, a YAG phase, and an Al ₅ O ₆ N phase were present. No magnesium component was present in the sintered body. Tables 1 and 2 show the production conditions and the physical properties of the sintered body.

Comparative Example 6 The aluminum nitride powder of Example 1 was mixed with yttrium oxide and magnesium oxide as sintering aids, and the same operation as in Example 1 was performed. When X-ray diffraction was performed, an aluminum nitride phase and a YAG phase were present. Tables 1 and 2 show the production conditions and the physical properties of the sintered body.

[0080]

[Table 1]

[0081]

[Table 2]

[0082]

According to the present invention, there is provided an aluminum nitride sintered body having a high thermal conductivity and a volume resistivity having a small temperature dependency in a wide temperature range.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the amount of magnesium present and the temperature dependence of volume resistivity in the present invention.

FIG. 2 is a view showing an X-ray diffraction peak of an aluminum nitride sintered body in one example of the present invention.

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Claims (7)

[Claims] 1. A crystal phase of Al ₅ O ₆ N and / or Al ₉ O ₃ N ₇ is dispersedly present in a matrix of an aluminum nitride sintered body and contains 0.1 to 2% by weight of magnesium. An aluminum nitride sintered body characterized by the above. 2. A peak intensity area of an aluminum nitride crystal (2θ = 49.5) obtained from an X-ray diffraction peak intensity area.
˜50.5 °) peak intensity area of Al ₅ O ₆ N crystal (2θ = 31.0 to 32.0 °) and Al ₉ O ₃
Area of peak intensity of N ₇ crystal (2θ = 70.5 to 71.5
The sum of the ratios of °) is 0.02 for 1 aluminum nitride.
It is -0.60, The aluminum nitride sintered compact of Claim 1 characterized by the above-mentioned. 3. The aluminum nitride sintered body according to claim 1, which has a volume resistivity of 1 × 10 ¹⁴ to 1 × 10 ⁸ Ω · cm in a temperature range of room temperature to 800 ° C. 4. The aluminum nitride sintered body according to claim 1, which has a thermal conductivity of 60 W / m · K or more. 5. A magnesium component is used as magnesium oxide in an amount of 1 to 100 parts by weight of aluminum nitride powder.
The method for producing an aluminum nitride sintered body according to claim 1, wherein a mixture containing 4.2 parts by weight and 2.5 to 9 parts by weight of aluminum oxide is molded and fired. 6. Magnesium oxide as a magnesium component and aluminum oxide as an Al ₅ O ₆ N and / or Al ₉ O ₃ N ₇ component are used, respectively, from 1750 to 1950.
The method for producing an aluminum nitride sintered body according to claim 5, wherein the firing is performed at 15 ° C. for 15 hours or more. 7. The method according to claim ₅ , wherein MgAl ₂ O ₄ is used as the magnesium component and the Al ₅ O ₆ N and / or Al ₉ O ₃ N ₇ component, and the firing is performed at 1750 to 1950 ° C. for 15 hours or more. Method for manufacturing aluminum nitride sintered body of.