JP3141505B2 - Aluminum nitride sintered body and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an aluminum nitride sintered body and an aluminum nitride sintered body. TECHNICAL FIELD The present invention relates to a method for producing an aluminum nitride sintered body having a high modulus and an aluminum nitride sintered body.

[0002]

2. Description of the Related Art Aluminum nitride (AlN) has been studied for use as a heat dissipating substrate because of its properties such as high electrical insulation, thermal expansion coefficient close to that of Si, and high thermal conductivity. In particular, by examining the AlN raw material powder and sintering method,
Research on improving the thermal conductivity, which is very important as a characteristic of, is being actively conducted in various fields.

In general, an AlN sintered body is obtained by mixing, mixing, granulating and molding AlN powder and a sintering aid such as a compound of an alkaline earth element or a rare earth element, and obtaining a sintered body by normal pressure sintering. Made by the method. These sintering aids such as alkaline earth and rare earth compounds react with oxygen unavoidably mixed into the AlN powder during sintering and consist of a composite oxide of alumina and the sintering aid. The formation of a liquid phase enables densification in the sintering process. In addition, the formation of the composite oxide also contributes to improving the thermal conductivity because, as a result, the impurity oxygen is fixed at the grain boundaries and the solid solution of oxygen in the grains is suppressed. . However, when the composite oxide finally remains in the sintered body, the thermal conductivity of the obtained AlN sintered body is limited, and its thermal conductivity is 170 W / mK
It was below.

At present, as the capacity of semiconductors is increased, materials having higher thermal conductivity are required for circuit boards for mounting semiconductors, heat radiation boards, and the like. In applying aluminum, it is necessary to eliminate problems such as the presence of oxygen and other impurities and the presence of a grain boundary phase generated at the grain boundary as a result of the addition of a sintering aid.

[0005] From this viewpoint, Japanese Patent Application Laid-Open No. 63-277573 discloses the addition of a yttrium and / or calcium compound to AlN powder as a sintering aid in order to provide an aluminum nitride sintered body having excellent thermal conductivity. By firing this in a reducing atmosphere containing nitrogen gas, the amount of grain boundary phase such as Y-Al-O-based compound and / or Ca-Al-O-based compound phase can be reduced by conventional aluminum nitride sintering. While reducing it compared to the body,
By performing sintering consisting of multi-stage sintering in two stages of low temperature and high temperature, we examined various optimum conditions to obtain aluminum nitride sintered body with high thermal conductivity, A method for producing aluminum has been proposed.
The mechanism of the reaction during the sintering process in the method for producing aluminum nitride described in Japanese Patent Application Laid-Open No. 63-277573 is such that when the composite oxide on the outermost surface is removed by the reductive nitridation reaction, a concentration gradient of the composite oxide occurs. It becomes the driving force and the internal composite oxide moves to the surface.
An N sintered body is produced.

[0006]

SUMMARY OF THE INVENTION
The method for producing aluminum nitride described in 63-277573 also has the following problem. That is, JP-A-63-277
The sintered body obtained by the method for producing aluminum nitride described in 573 has a different composition of the sintering aid forming the composite oxide at the outermost surface and the central portion, and has uniform characteristics, particularly uniform thermal conductivity. In order to obtain a sintered body, sintering at a high temperature for a long time in a reduced nitrogen atmosphere is necessary, which is an impractical method in terms of productivity in an industrial production process.
In particular, depending on the method of manufacturing aluminum nitride described in Japanese Patent Application Laid-Open No. 63-277573, a large-sized thick AlN sintered body is produced with uniform high thermal conductivity in the thickness direction in an industrial production process. It is not possible.

[0007] The present invention has been made in view of the above-mentioned problems in the prior art, and has as its object to provide an aluminum nitride sintered body having excellent thermal conductivity and uniform characteristics.

[0008]

In order to achieve the object of the present invention, the present inventor has added a sintering aid to aluminum nitride powder,
Various experiments and studies were conducted on the relationship between the sintering conditions, the sintered body composition, the sintered body microstructure, and the like, and the thermal conductivity, and the present invention was created based on newly discovered new matters.

That is, an alkaline earth element and / or
Alternatively, a predetermined amount of a rare earth element is added, an organic binder is added, and further, a carbon source as a substance for reducing a complex oxide at a grain boundary in a sintering process, for example, carbon itself, or a heat treatment in a non-oxidizing atmosphere, Add organic binders and the like that generate carbon, pulverize and mix them using a ball mill, etc.
Granulate with a flat layerer. Next, the granulated powder is formed into a predetermined shape, and then heated to remove hydrogen and oxygen contained in the binder. Subsequently, the compact is set in a sintering furnace, and the sintering temperature is set to 1200 to 19 in a nitrogen gas atmosphere.
Perform the first stage sintering at 00 ° C, and at 1800-2200 ° C,
Perform second-stage sintering for 5 hours. The thermal conductivity of the AlN sintered body thus manufactured is uniform, and the thermal conductivity of the sintered body is 170 W / m · K or more.

The present invention has been made based on such new findings. That is, the method for producing an aluminum nitride sintered body of the present invention comprises mixing aluminum nitride with carbon (C) and / or a carbon-containing material and a rare earth and / or alkaline earth compound, and forming a mixed powder into a sphere having a diameter of 10 mm. Molded into a molded article having a geometric shape that can be included at least in part as an outer shape,
The first stage sintering is performed at a temperature equal to or lower than the liquid phase generation temperature, and the second stage sintering is performed at a temperature equal to or higher than the liquid phase generation temperature. In addition, the method for producing an aluminum nitride sintered body of the present invention includes a geometrical shape containing aluminum nitride, carbon (C), a rare earth and / or an alkaline earth compound as components, and at least partially including a sphere having a diameter of 10 mm. The first stage sintering is performed on the object to be sintered having an outer shape at a temperature equal to or lower than the liquid phase generation temperature, and the second stage sintering is performed at a temperature equal to or higher than the liquid phase generation temperature. .

Further, the aluminum nitride sintered body of the present invention has a diameter
In an aluminum nitride sintered body having a three-dimensional shape having an outer shape that can at least partially include a sphere of 10 mm, the thermal conductivity at a position corresponding to the center point of the sphere and an arbitrary point outside the sphere correspond to The ratio of the position to the thermal conductivity is 0.85 or more. The aluminum nitride raw material powder used in the present invention preferably contains 1.5% by weight or less of oxygen, and practically 0.01 to 1.0% by weight.
In addition, the average particle size, when considering the sinterability and thermal conductivity,
It is preferably about 0.5 to 5 μm.

In the present invention, the additive added as a sintering aid is a rare earth element compound and / or an alkaline earth element compound. Compounds of rare earth elements and alkaline earth elements include oxides of rare earth elements and alkaline earth elements,
Examples include nitrides, fluorides, oxyfluorides, oxynitrides, and substances that become these compounds by firing. For example, substances that become these oxides by firing include carbonates, nitrates, oxalates, and hydroxides of rare earth elements and alkaline earth elements. The amount of the rare earth and / or alkaline earth element compound is preferably 0.5 to 15% by weight. If the content is less than 0.5% by weight, the effect of the additive is not sufficiently exerted, the densification of the sintered body becomes insufficient, and oxygen is dissolved in the AlN crystal to form a high heat conductive sintered body. On the other hand, when the content exceeds 15% by weight, a problem occurs that the grain boundary phase remains in the sintered body and the volume of the grain boundary phase removed in the heat treatment process increases. The amount of the rare earth and / or alkaline earth compound added is preferably 4.0 to 12% by weight, more preferably 5 to 12% by weight.
It is good to be ~ 10% by weight.

In the present invention, a carbon-containing substance is added to the sintered body as a binder, for example, so that carbon can contribute to the reduction of the composite oxide in the mixed powder or in the sintering process. Perform a knot. The amount of carbon to be added can be appropriately adjusted depending on the amount of oxygen present in the AlN raw material powder and the ultimately desired thermal conductivity of the sintered body. For example, the amount of oxygen present in the raw material powder is 0.5 to 1.5 wt.
%, And when the target thermal conductivity is 170 to 200 W / m · K, the amount of the carbon-containing substance is suitably 0.5 to 1.5 wt% in terms of the amount of carbon.

In the present invention, the firing atmosphere in the sintering process is a non-oxidizing atmosphere containing nitrogen gas. Non-oxidizing atmosphere, such as CO ₂ , H ₂ gas and C (gas and solid phase),
It can be made by the presence of one or more. CO as a non-oxidizing atmosphere, especially a reducing atmosphere
In case of atmosphere, partial pressure 0.01 × 10 ^{5 to} 1.5 × 10 ⁵ P
It is preferable to use a gas generated to a degree in the sintering temperature range of 1200 to 1900 ° C. Such a carbon case reduces the AlN during firing and removes the grain boundary phase from the sintered body to convert the aluminum nitride sintered body into an AlN single phase, thereby obtaining an AlN sintered body having high thermal conductivity. . The grain boundary phase removed by the carbon gas is a ternary compound of (rare earth element) -Al-O and / or (alkaline earth element) -Al-O.

In the present invention, the firing container used for sintering is most simply a container made of carbon. That is, a container made of h-BN aluminum nitride, alumina, or Mo can be used as the firing container, but in the present invention, a container that creates a carbon gas atmosphere during firing can also be used. Preferred for the purpose of the invention. As a container for creating the atmosphere of the carcass, an entire container is made of a car- phone, an entire container is made of a car- phone, and an AlN plate is provided at a place where a sample is placed.
An object in which a BN plate, a W plate, or the like is laid, an aluminum nitride container having an upper lid made of carbon, or the like can be used.

Next, the sintering time and the sintering temperature in the present invention will be described. Sintering time and sintering temperature use
It varies depending on the particle size of the AlN raw material powder, the amount of oxygen and the type of sintering aid.

In the sintering process of the method for producing aluminum nitride according to the present invention, in the first stage sintering, the temperature is raised at a temperature of 1200 to 1900 ° C. and 0.5
It is good to be ~ 10.0 ° C / min. If it is less than 0.5 ° C./min, the sintering time becomes too long, and if it exceeds 10.0 ° C./min, the reduction is not performed sufficiently. In the first stage of sintering, oxygen on the surface of the raw material powder is trapped in the grain boundary phase and then reduced. In particular, when a rare earth element compound is used as a sintering aid, when sintering at a high temperature from the beginning, a (rare earth element) -N compound is generated and remains in the sintered body,
This causes a decrease in thermal conductivity. Further, when an alkaline earth element compound is used as a sintering aid, if the sintering is carried out at a high temperature from the beginning, the alkaline earth element is volatilized, so that the AlN compact is not densified.

Next, in the second stage sintering, 18
Sintering at 00 to 2100 ° C for 0.5 hour or more, preferably 2 hours or more is good. If the sintering time is less than 0.5 hours, densification, removal of the grain boundary phase, and high thermal conductivity due to grain growth do not sufficiently proceed, and an AlN sintered body with high thermal conductivity cannot be obtained.

As a result of measuring and analyzing the characteristics and the structure of the AlN sintered body obtained by the above-described method for manufacturing an aluminum nitride sintered body of the present invention, it was found that the AlN sintered body had a very high 170 watts as a polycrystal.
/ mK or higher thermal conductivity component phase is only AlN grains or Al
N grains and rare earth and alkaline earth oxides, no other phases are observed. It has been found. The final impurity oxygen of the aluminum nitride sintered body obtained by the production method of the present invention is
Preferably, the content is 2.0 wt% or less. If the impurity oxygen is contained in excess of that, the adverse effect on the object of the present invention, that is, the uniform improvement of the thermal conductivity occurs.

[0020]

Next, a description will be given of factors that achieve a uniform high thermal conductivity in the aluminum nitride sintered body obtained by the method for producing aluminum nitride of the present invention. According to the present invention, by adding a rare earth and / or alkaline earth element compound as a sintering aid, impurity oxygen can be reduced to (rare earth element) -Al-O and / or (alkaline earth element) -Al-O system. AlN in the form of compounds, etc.
As a result of being fixed at the grain boundaries and preventing solid solution of oxygen in the AlN lattice, formation of Al oxynitride (AlON) and AlN polytype (27R type) is prevented. Suppressing the cause of the low thermal conductivity in this way contributes to the high thermal conductivity.

In the early stage of the first sintering process, for example, when Y is selected as a rare earth element, 3Y ₂ O ₃ , Al ₂ O ₃ , Y ₂ O
_{3 · Al 2 O 3, 2Y} 2 O 3 · Al 2 O 3, Y 2 O compounds such as _5, when you choose Ca as an alkaline earth _{element, 1CaO · 6Al 2 O 3,} 1CaO · 2Al 2 O 3 ,
1CaO · 1Al ₂ O _3, compounds such as CaO is produced. Next, in the subsequent sintering process, carbon (C) that is uniformly dispersed in the sintered body
Reduces the grain boundary phase uniformly throughout the sintered body, and the grain boundary phase is gradually removed. As a result, the grain boundary phase moves out of the system of the sintered body, and the sintered body becomes an AlN single phase and the thermal conductivity uniformly increases. That is, the atmosphere outside the sintered body contributes as a carbon dioxide atmosphere, and the outermost composite oxide is removed by the reductive nitridation reaction, and a concentration gradient of the composite oxide is generated. Unlike the conventional mechanical method of manufacturing aluminum nitride, which moves to the surface, in the present invention, carbon (C) is uniformly dispersed and mixed in the sintered body, particularly before sintering, and the inside of the sintered body is Since the reductive nitridation reaction of the composite oxide proceeds substantially uniformly in the entire sintered body including the sintered body, a uniform high thermal conductivity is achieved in the entire sintered body. Also, calcination for a long time is not necessary, and AlN particles of the sintered body grow even in a relatively short time, the number of grain boundaries that become a thermal resistance decreases, and aluminum nitride can be treated in a short time that is industrially applicable. Thermal conductivity can be improved uniformly.

[0022]

Next, the present invention will be described specifically with reference to examples and comparative examples.

Example 1 Oxygen as an impurity was contained in an amount of 1.2% by weight, and the average particle diameter was 0.5%.
Yttrium oxide (Y
₂ O ₃ ) 5.7% by weight, and further 0.6% by weight of carbon powder were added. This mixed powder was mixed and granulated by a ball mill, and then formed into a rectangular compact of 100 × 100 × 15 mm by press molding (1000 kg / cm 2). As shown in FIG. 1, this molded body is a molded body 2 having, as an outer shape, a geometrical shape capable of at least partially including a sphere 1 having a diameter of 10 mm. Further, the sintered body obtained by removing the binder from the molded body 2 was accommodated in a BN container, and sintered under normal pressure under the following conditions. (1) Sintering temperature, heating rate, sintering time (2) Sintering atmosphere Nitrogen gas-1 atm By sintering above, the final carbon content is reduced to 0.02 wt% and oxygen content is reduced to
A sintered body reduced to 1.5 wt% was obtained. The obtained sintered body was analyzed, and the carbon content, the oxygen content, and the thermal conductivity were measured.
In the thermal conductivity measurement, the thermal conductivity at a position A corresponding to the center point of the sphere 1 and the thermal conductivity at a position B corresponding to an arbitrary point outside the sphere 1 are measured, and the ratio is determined. I asked.
Table 1 shows the above results. FIG. 4 shows the relationship between the distance from the center of the sintered body of the sphere 1 and the thermal conductivity.

Example 2 A sintered body was obtained in the same manner as in Example 1 except that 7.0% by weight of calcium sprosium oxide (Dy ₂ O ₃ ) (in terms of the weight of calcium spherurosium) was added as a sintering aid. The characteristics of the sintered body were evaluated in the same manner as described above. The results are shown in Table 1. FIG. 5 shows the relationship between the distance from the center of the sphere 1 and the thermal conductivity.

Example 3 A sintered body was obtained in the same manner as in Example 1 except that the heating rate in the first stage sintering was set at 3 ° C./min. evaluated. The results are shown in Table 1.

Example 4 The temperature rise rate of the first stage sintering was 5 ° C./min, and the final carbon amount was
A sintered body was manufactured in the same manner as in Example 1 except that 0.03 wt% and the amount of oxygen were 1.7 wt%. The characteristics of the sintered body were evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 5 A sintered body was manufactured in the same manner as in Example 1 except that the sintering temperature range of the first stage sintering was 1200 to 1500 ° C., and the heating rate was 0.5 ° C./min. The characteristics of the sintered body were evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 6 A sintered body was produced in the same manner as in Example 1 except that Sc was added as a sintering aid. The characteristics of the sintered body were evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 7 A sintered body was produced in the same manner as in Example 1 except that Sr was added as a sintering aid. The characteristics of the sintered body were evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 8 A sintered body was produced in the same manner as in Example 1 except that Ca was added as a sintering aid. The characteristics of the sintered body were evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 9 A sintered body was produced in the same manner as in Example 1 except that Ce was added as a sintering aid. The characteristics of the sintered body were evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 10 A sintered body was produced in the same manner as in Example 1 except that Ba was added as a sintering aid. The characteristics of the sintered body were evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 11 A sintered body was manufactured in the same manner as in Example 1 except that Er was added as a sintering aid. The characteristics of the sintered body were evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 12 As shown in FIG. 2, a molded body 3 of 20 × 20 × 20 mm was formed as a molded body having a geometrical shape capable of at least partially including a sphere 1 having a diameter of 10 mm. A sintered body was manufactured in the same manner as in Example 1 except for tying. The characteristics of the sintered body were evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 13 Oxygen as an impurity was contained in an amount of 1.2% by weight, and the average particle size was 0.5%.
As a sintering aid, 5.7% by weight of disulfide (Dy ₂ O ₃ ) was added to the aluminum nitride powder of μm (in terms of the weight of disulfide). This mixed powder was mixed and granulated by a ball mill, and then molded. In molding, the carbon-containing organic resin-based binder was converted to a carbon content of 0.8% by weight, granulated, and further subjected to pressure molding (1000 kg / cm2) to obtain 100 × as shown in FIG.
It was formed into a green compact 2 having a rectangular shape of 100 × 15 mm. Further, the sintered body obtained by removing the binder other than carbon from the molded body in N ₂ was accommodated in a container made of carbon dioxide and sintered under normal pressure under the following conditions. (1) Sintering temperature, heating rate, sintering time First stage sintering -1200 to 1800 ° C (less than liquid phase forming temperature) Heating rate 1 ° C / min Second stage sintering-1950 ° C (liquid phase forming (More than temperature) 1h (2) Sintering atmosphere CO gas Partial pressure -0.2 × 10 ⁵ Pa Nitrogen gas Partial pressure -1.8 × 10 ⁵ Pa Sintering above results in a final carbon content of 0.03 wt%, oxygen The amount
A sintered body reduced to 1.6 wt% was obtained. The obtained sintered body was analyzed, and the oxygen content, density, particle size, and thermal conductivity were measured.

COMPARATIVE EXAMPLE 1 In the same manner as in Example 1 except for the above, a green body produced from granulated powder without carbon was sintered in a reducing atmosphere consisting of a container made of carbon. Table 1 shows the results of investigating the characteristics of the obtained sintered body in the same manner as in Example 1. FIG. 4 shows the relationship between the distance from the center of the sintered body of the sphere 1 and the thermal conductivity.

COMPARATIVE EXAMPLE 2 In the same manner as in Example 2 except for the above, a compact produced from granulated powder without carbon was sintered in a reducing atmosphere. Table 1 shows the results obtained by examining the characteristics of the obtained sintered body in the same manner as in Example 2. FIG. 5 shows the relationship between the distance from the center of the sphere 1 and the thermal conductivity.

Comparative Example 3 In particular, the sintering temperature range was set to 0 to 2000 ° C. and the temperature was raised at a rate of 5 ° C./min. An aluminum nitride sintered body was manufactured in the same manner as in Example 1 except that the sintering was carried out. Table 1 shows the results of investigating the characteristics of the obtained sintered body in the same manner as in Example 1.
Shown in

[0039]

[Table 1]

As can be seen from Table 1 showing the characteristics of the sintered bodies obtained in each of the above Examples and Comparative Examples, the sintered bodies of the Examples all had a thermal conductivity of 170 or more, and in particular, FIG. ,
It is confirmed that the ratio between the thermal conductivity at the position A corresponding to the center point of the sphere shown in FIG. 2 and the thermal conductivity at the position B corresponding to an arbitrary point outside the sphere is 0.85 or more. . On the other hand, the sintered bodies of Comparative Examples 1, 2, and 3 have the thermal conductivity at the position A corresponding to the center point of the sphere and the position B corresponding to an arbitrary point outside the sphere shown in FIGS. The ratio with the thermal conductivity of 0.
It is less than 85, and it is confirmed that the thermal conductivity in each part of the sintered body is not uniform. Regarding this point, particularly in the sintered bodies of Examples 1 and 2 as shown in FIGS. 4 and 5, even when the distance from the center of the sphere 1 increases, the thermal conductivity shows a substantially uniform high value. On the other hand, in the sintered bodies of Comparative Examples 1 and 2, the thermal conductivity at the center of the sphere 1 was low, and as the distance from the center increased, the thermal conductivity tended to increase. It can be seen that the thermal conductivity is not uniform between the central portion and the outer portion, and the thermal conductivity is particularly low at the central portion. Further, even without the addition of carbon, a sintered body having a geometrical shape in which a sphere having a diameter of 10 mm cannot be contained inside has a ratio of the internal thermal conductivity to the external thermal conductivity of 0.85.
From the above, it can be seen that the method for producing an aluminum nitride sintered body of the present invention is particularly effective as a method for obtaining a large-sized sintered body having a geometric shape capable of containing a sphere having a diameter of 10 mm inside.

[0041]

As described above, according to the method for producing an aluminum nitride sintered body of the present invention, AlN having uniform properties and high thermal conductivity can be obtained. Further, according to the aluminum nitride sintered body of the present invention, the heat of a large aluminum nitride sintered body having a three-dimensional shape having an outer shape that can at least partially include a sphere having a diameter of 10 mm corresponds to the central point of the sphere. Since the ratio between the conductivity and the thermal conductivity at a position corresponding to an arbitrary point outside the sphere is 0.85 or more, a strong heat dissipation function is exhibited, and the large sintered body is cut for use. Also in this case, an extremely excellent effect that the problem of non-uniformity in characteristics such as thermal conductivity of individual cut pieces does not occur is exhibited.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a form of a sintered body according to one embodiment of the present invention.

FIG. 2 is a perspective view showing a form of a sintered body according to another embodiment of the present invention.

FIG. 3 is a view showing the thermal conductivity uniformity of the sintered body of Example 1 of the present invention and the sintered body of Comparative Example 1 in comparison.

FIG. 4 is a diagram showing the uniformity of thermal conductivity of the sintered body of Example 2 of the present invention and the sintered body of Comparative Example 2 in comparison.

[Explanation of symbols] A spherical center point B position corresponding to an arbitrary point outside the spherical body 1 spherical body 2, 3 molded body

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C04B 35/581-35/5835 C04B 35/64

Claims (5)

(57) [Claims] An aluminum nitride and carbon (C) and / or
Alternatively, a carbon-containing material is mixed with a rare earth and / or alkaline earth compound, and the mixed powder is formed into a molded product having a diameter of 10%.
It is characterized in that it is formed into an outer shape containing a sphere of mm, and the first stage of sintering is performed at a temperature equal to or lower than the liquid phase generation temperature, and the second stage is sintered at a temperature equal to or higher than the liquid phase generation temperature. A method for producing an aluminum nitride sintered body. 2. An outer shape containing a sphere having a diameter of 10 mm.
That the aluminum nitride sintered body, any sintered body section
An aluminum nitride sintered body characterized in that a thermal conductivity ratio at an arbitrary position is 0.85 or more between two arbitrary points . 3. The aluminum nitride sintered body according to claim 2 , having a thermal conductivity of 170 w / m · k or more. 4. The method according to claim 1, wherein the sintering is performed in a non-oxidizing atmosphere.
3. The method for producing an aluminum nitride sintered body described in 1. above. 5. The sintering temperature in the first stage is set at 1200 to 190.
0 ° C. and the sintering temperature of the second stage is 1800-2
The method for producing an aluminum nitride sintered body according to claim 1, wherein the temperature is set to 100 ° C.