JPH0977558A - Production of aluminum nitride sintered compact - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a low-cost producing process corresponding to the reduction of the sintering temp. of an AlN sintered compact. SOLUTION: Stock of an AlN sintered compact having a compsn. sinterable at a low temp. is fired at <=1,873K in an atmosphere of nitrogen or argon contg. <=100ppm oxygen in an electric resistance furnace using an oxide furnace material fitted with a metallic heater to produce the objective AlN sintered compact having 100-180W/mK heat conductivity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an aluminum nitride (AlN) sintered body, which has a thermal conductivity of 1
The present invention relates to a method for inexpensively producing an AlN sintered body of 00 to 180 W / m K.

[0002]

2. Description of the Related Art An AlN sintered body is attracting attention as a substrate material for mounting semiconductors because it has excellent thermal conductivity as compared with alumina ceramics and has a thermal expansion coefficient almost equal to that of silicon. Further, since it has properties such as high strength at high temperature and no reactivity with molten metal, its application to circuit boards and other fields is being promoted.

However, the application of the AlN sintered body is developing much later than originally expected. AlN
Despite the fact that the characteristics of the sintered body, such as a circuit board, are significantly higher than those of conventional alumina ceramics, etc.,
High cost is nothing more than the biggest factor behind the lack of actual use. It is considered that the reason for the high cost of the AlN sintered body is that the mass production technology as found in alumina ceramics is not sufficiently prepared, rather than the price of the raw material powder.

That is, the AlN sintered body is a material that is difficult to sinter, and in order to obtain high thermal conductivity, a sintering aid that traps oxygen in AlN crystal grains, such as an alkaline earth metal compound or a rare earth compound. It is necessary to add and sinter at a high temperature around 2073K. In this way, since the sintering temperature is as high as about 2073K, the amount of energy consumed for sintering is large, and in addition, a sintering furnace using expensive high temperature furnace material must be used. Under these circumstances, the manufacturing cost of AlN sintered bodies is significantly higher than that of alumina ceramics or the like.

On the other hand, as described in, for example, JP-A-61-209959, JP-B-5-17190, JP-A-62-153173, etc., the low temperature of AlN sintered bodies has recently been increasing. Although it is becoming possible to sinter, batch-type furnaces using conventional high-temperature furnace materials are still used in the sintering furnace.
The actual manufacturing cost is no different from that of the conventional high temperature sintered AlN sintered body.

[0006]

As described above, the conventional high temperature sintered AlN sintered body has a large amount of energy consumed for sintering and, in addition, a sintering furnace using an expensive high temperature furnace material. However, the manufacturing cost is significantly higher than that of alumina ceramics and the like. On the other hand, low-temperature sintering technology for AlN sintered bodies has also been developed, but the conventional low-temperature sintering technology for AlN sintered bodies has no difference in actual manufacturing cost from high-temperature sintered AlN sintered bodies. At present, however, the reduction in manufacturing cost commensurate with the decrease in sintering temperature has not been realized.

From the above, the development of a low-cost manufacturing process commensurate with the low-temperature sintering of AlN sintered body is based on the fact that AlN has higher thermal conductivity than alumina ceramics and the like.
It is said to be the biggest issue in expanding the range of applications for sintered compacts.

The present invention has been made in order to solve such a problem, and in accordance with the decrease of the sintering temperature of the aluminum nitride sintered body, the manufacturing cost can be reduced. It is intended to provide a method for producing a bound body.

[0009]

A method of manufacturing an aluminum nitride sintered body according to the present invention has a metal heater and
In an electric resistance furnace using an oxide furnace material, an aluminum nitride sintered body raw material having a low temperature sintering composition was used, in which the amount of oxygen present was 1
In a nitrogen or argon atmosphere of 00ppm or less, and 187
Characterized by firing at a temperature of 3 K or less, the thermal conductivity is
This is a method for producing an aluminum nitride sintered body of 100 to 180 W / mK.

In the method for manufacturing an aluminum nitride sintered body of the present invention, an electric resistance furnace having an oxide furnace material is used while having a metal heater. An electric resistance furnace using such an oxide furnace material is inexpensive in itself, and
The continuous firing furnace can reduce the manufacturing cost. However, in such an electric resistance furnace, it is difficult to reduce the amount of oxygen present even in an inert atmosphere such as nitrogen or argon, and it is difficult to reduce the amount of oxygen in aluminum nitride by conventional high-temperature sintering at around 2073K. A solid solution is likely to occur, and a practical aluminum nitride sintered body cannot be obtained. On the other hand, in the present invention, since the raw material of the aluminum nitride sintered body having the low temperature sintering composition is fired at a temperature of 1873 K or less, the solid solution of oxygen into the aluminum nitride through the gas phase and the sintered body Oxidation, etc. can be almost ignored. Therefore, the thermal conductivity
It is possible to inexpensively manufacture an aluminum nitride sintered body of 100 to 180 W / m K, that is, an aluminum nitride sintered body that has sufficiently high thermal conductivity with respect to an alumina sintered body or the like.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Modes for carrying out the present invention will be described below.

As the AlN powder used in the present invention, virtually any available powder can be used. However, in order to improve the sinterability and thermal conductivity, the amount of impurity oxygen is 0.2 to 3.0% by weight. %, And the average primary particle size is
It is preferable to use AlN powder in the range of 0.3 to 2.5 μm. If the average particle size of the AlN powder is less than 0.3 μm, it may be difficult to mold the mixed powder.
If it exceeds 2.5 μm, the low-temperature sinterability will decrease. The more preferable average particle diameter of the AlN powder is in the range of 0.4 to 2.0 μm. Further, if the amount of impurity oxygen in the AlN powder is less than 0.2% by weight, AlN may be deteriorated in the handling stage such as mixing or molding before sintering, or the sintering may not proceed sufficiently,
On the other hand, if it exceeds 3.0% by weight, the thermal conductivity of the final AlN sintered body may decrease. A more preferable range of the amount of impurity oxygen is 0.4 to 2.5% by weight. A as described above
Various additives that function as a sintering aid, an oxygen getter, and the like are mixed with 1N powder to prepare an AlN sintered body raw material having a low-temperature sintering composition. As the additive that realizes the low temperature sintering composition, first, a simple substance and / or a compound of an alkaline earth metal element and a rare earth element can be mentioned. These are added as powders or liquids. When added as a powder, it is preferable to use a powder having an average particle diameter of 0.04 to 1.5 μm. Specifically, an alkaline earth metal element or a rare earth element can be added as an oxide, a carbide, a fluoride, an oxyfluoride, a carbonate, an oxalate, a nitrate, an alkoxide, or the like. Further, various combinations are possible, such as adding the alkaline earth compound powder and then adding the nitrate of the rare earth element by dissolving it in alcohol. In the case of an oxide or a compound that becomes an oxide during firing, the alkaline earth metal compound and the rare earth compound are simultaneously added,
Low temperature sintering of 3K or less can be realized. When added as a fluoride or the like, low temperature sintering of 1873K or less is possible even if added alone.

As the above-mentioned alkaline earth metal element,
Mg, Ca, Ba, Sr and the like can be used, and as the rare earth element, Sc, Y and lanthanum series elements can be used. The compounds of the alkaline earth metal element and the rare earth element are preferably added in the range of 0.1 to 10% by weight. The addition amount of these is 0.1
If it is less than 10% by weight, sintering may be insufficient, or even if it is sufficiently sintered, it may be difficult to achieve a thermal conductivity of 100 W / m K or more. On the other hand, if it exceeds 10% by weight, many precipitates may appear on the surface of the sintered body, or the thermal conductivity may decrease if the sintering time is short.

As the raw material of the AlN sintered body having the low temperature sintering composition, the following alkali metal compounds are converted into oxides.
It can be added in an amount of not more than wt%. Particularly preferred alkali metal compounds are compounds of Na and K, specifically N
Examples thereof include carbonates and nitrates of a and / or K, nitrates, oxalates, fluorides, chlorides, borates such as Na ₂ B ₄ O ₇ , and compounds that change to these compounds during firing. If these alkali metal compounds are added in an amount of more than 2% by weight, color unevenness or baking unevenness may easily occur, or conversely, the sinterability may decrease.
The addition amount is preferably 2% by weight or less.

Further, Si compounds such as SiO ₂ , Si ₃ N ₄ and SiC, and B ₂ O ₃ or B _{2 during} firing
A compound that changes to O ₃ (for example, Η ₃ BO ₃ ) or the like may be added in the range of 2% by weight or less in terms of oxide. These are also compounds that enhance low-temperature sinterability, but if they are added in excess of 2% by weight, color unevenness or baking unevenness may easily occur, or the thermal conductivity may decrease.

The AlN sintered body raw material of the low temperature sintering composition used in the present invention includes, in addition to the above-mentioned various additives, oxides, nitrides and carbides of Group 4B elements such as GeO ₂ and Al ₂ O.
Oxides, halides and the like of 3B group elements such as ₃ , AlF ₃ and GaF ₃ can be added in an amount of 1% by weight or less in terms of oxides. Further, a transition metal simple substance or compound can be added mainly for coloring or blackening the AlN sintered body. Examples of the transition metal compound include Ti, Nb, Zr, Ta, W, Mo, Cr, Fe,
Examples thereof include Co, Ni oxides, nitrides, carbides, oxycarbides, and oxynitrides. Since it is desirable that these have conductivity in the sintered body, for example, simple metals such as W and Mo, and nitrides and carbides of elements selected from Zr, Ti, Nb and Ta are preferably used. The addition amount of these is preferably 1.5% by weight or less.

In the present invention, an AlN sintered body is manufactured by the following method using the AlN sintered body raw material having the above-mentioned low temperature sintering composition. First, an organic binder and an organic solvent are added to an AlN sintered body raw material having the above-described low temperature sintering composition, and the mixture is crushed and mixed by, for example, a ball mill.
Such a mixture is formed into a desired shape by forming it into a sheet by a doctor blade method or by press forming. As the organic binder, for example, acrylic type, methacrylic type, PVB type or the like is used. As a solvent for dispersing these organic binders, for example, alcohols such as n-butanol, methyl isobutyl ketone, toluene, xylene and the like are used. The amount of organic binder added varies depending on the particle size of the AIN powder used.
It is preferably in the range of 20 to 20% by weight, and more preferably in the range of 4 to 16% by weight.

Next, the organic binder is removed by heating usually in a non-oxidizing atmosphere such as nitrogen or argon. The maximum temperature required for binder removal is approximately 1073K in the above non-oxidizing atmosphere and 823K in the atmosphere containing oxygen.
The degree is appropriate. Usually, the heating rate is 10 to 200 K / h, and more preferably 30 to 100 K / h.

After performing the above-mentioned binder removal, in an electric resistance furnace having a metal heater and using an oxide furnace material, at a temperature of 1873K or less in a nitrogen or argon atmosphere in which the amount of oxygen present is 100ppm or less. Bake at. As the metal heater, a heater made of W or Mo is used, and usually the metal heater is used in a rod shape or a mesh shape. As the oxide furnace material, for example, the main component is Al ₂ O ₃ , and 0.1 to 5 parts by weight of alkaline earth oxides such as CaO and MgO and transition metal oxides such as ZrO ₂ and ΤiO ₂ are contained as auxiliary components. %, And the SiO ₂ content is
Those in the range of 0.1 to 5.0% by weight are used. Since SiO ₂ has a high vapor pressure and is likely to form a solid solution in the AlN sintered body, the content in the oxide furnace material is preferably 5.0% by weight or less. The electric resistance furnace using such a metal heater and oxide furnace material can be used as a continuous firing furnace which can reduce the manufacturing cost while the furnace itself is inexpensive.

The binder removed body of AlN is, for example, AlN,
It is placed in a firing container made of h-BN, W, Mo, Al ₂ O ₃ , etc., in a non-oxidizing atmosphere such as a nitrogen atmosphere or an argon atmosphere at a temperature of 1873 K or less, specifically a temperature of 1673 to 1873 K. Bake at. The non-oxidizing atmosphere is not limited to a single atmosphere of nitrogen or argon, but may be a mixed gas atmosphere in which hydrogen or carbon dioxide gas is partially added. In an electric resistance furnace using an oxide furnace material, oxygen is contained in the firing atmosphere, but the amount of oxygen in the atmosphere is allowed to be 100 ppm or less. In other words, when sintering AlN at a temperature of 1873K or lower, if the amount of oxygen in the firing atmosphere is 100ppm or less, the solid solution of oxygen into AlN via the gas phase or the oxidation of the sintered body may occur. Problems such as defective sintering can be almost ignored, and an AlN sintered body having a thermal conductivity of 100 to 180 W / m K can be obtained. If the firing temperature is 1873 K or less, the oxygen amount in the atmosphere can be 100 ppm or less when the oxide furnace material having the above-described composition is used.

Sintering is usually performed in an atmosphere of 0.01 to 10 atm in a state of being housed in a sintering container. Normally, the sintering container has a lid, but if it is shielded so that the volatilized material from the metal heater does not directly contact the sintered body, it can be sintered even in an open container without a lid. The sintering temperature is preferably in the range of 1673 to 1873K as described above. If the sintering temperature is less than 1673K, it is difficult to densify sufficiently even if the AlN sintered body raw material having the above-mentioned low temperature sintering composition is used. Reduction cannot be realized. In other words, the service temperature of the oxide furnace material, the amount of oxygen in the firing atmosphere and Al
Oxidation of the N sintered body makes it difficult to use the oxide furnace material and causes an increase in the amount of energy consumed for sintering. In either case, it is impossible to reduce the manufacturing cost of the AlN sintered body.

The sintering time is usually 0.5 to 16 hours at the maximum temperature, and more preferably 2 to 8 hours. In the sintering schedule, the temperature can be monotonically raised to the maximum temperature, but the temperature can be raised stepwise to the maximum temperature if necessary. The heating rate is 50 to 2000 K / hour, more preferably 200 to 1000 K / hour. The rate of temperature decrease can be the same, but it is preferably 100 K / hour or less in order to crystallize the grain boundary phase in the sintered body and increase the thermal conductivity.

According to the above-mentioned manufacturing method, the AlN sintered body having a thermal conductivity of 100 to 180 W / m K, that is, the AlN sintered body having a sufficiently high thermal conductivity is maintained.
A sintered body can be manufactured. And, the production cost corresponding to the low temperature sintering of the AlN sintered body of 1873K or less can be reduced. That is, it is possible to reduce the energy required for use and sintering of an electric resistance furnace using an inexpensive metal heater and oxide furnace material, and it is possible to allow an oxygen amount of 100 ppm or less in the firing atmosphere. Is.

Al manufactured by applying the manufacturing method of the present invention
The N sintered body can be used as a high-temperature high-strength material, a heat sink, or the like, but is preferably used as various circuit boards, package bases, or the like by forming a conductor layer by metallization, co-firing, or the like. . Specifically, DBC
It is used as various circuit boards by forming a conductor circuit by a thin film method, a thin film method, a thick film method or the like. Further, by forming the conductor layer by simultaneous firing, QFP, PGA, BG
It can also be used as a package base for A, DIP and the like. As the conductor material, W, Mo, Pt, Pd, N
i or the like can be used.

An example of a method of manufacturing the above-mentioned circuit board will be shown below. First, for example, in the first step, the AlN green sheet as described above is produced, and in the second step, the conductive paste is applied to at least one surface of the AlN green sheet in a predetermined circuit pattern shape by screen printing, for example. At this time, in order to form a multilayer circuit, a hole is made in the green sheet in advance, and the hole is filled with a conductive paste by, for example, a press-fitting method to obtain an electrical connection between layers. If necessary, a circuit pattern is further formed on the surface, and hot pressing is performed to stack the green sheets. In the third step, the binder in the green sheet is removed by heating and then sintered according to the manufacturing method of the present invention. After sintering, trimming, circuit formation by thin film or thick film, formation of external electrodes, etc. are performed as necessary.

[0026]

EXAMPLES Specific examples of the present invention will be described below.

Example 1 The amount of impurity oxygen was 1.1% by weight, and the average primary particle size was 1.5 μm.
95.45% by weight of mN AlN powder, 3% by weight of Y ₂ O ₃ ,
CaCO ₃ is 1.0 wt% in terms of CaO and LaB ₆ is 0.25
%, And WO ₃ was added in an amount of 0.3% by weight in terms of W. This mixed powder was sufficiently mixed using a ball mill with n-butanol as a dispersion medium. After removing the n-butanol,
An acrylic binder dispersed in xylene was added so that the amount of the binder would be 5% by weight, and the mixture was sufficiently mixed to form a paste, and then xylene was removed. The obtained powder was passed through a mesh having an opening of 0.3 mm to obtain granulated powder.

The granulated powder was molded into a block shape under a pressure of 50 MPa and then heated in a nitrogen gas at a maximum temperature of 973 K to remove the binder. The binder-removed body was set in a firing container composed of an AlN ceramic plate and an alumina ring, and a rod-shaped tungsten heater was provided.
In an electric resistance furnace using an oxide furnace material mainly containing 1 ₂ O ₃ , 0.6% by weight of MgO and 0.5% by weight of SiO ₂ , the temperature was raised to 1853K at a heating rate of 500K / h. It was held at this temperature for 3 hours for sintering. The amount of oxygen in the atmosphere during firing was 100 ppm or less.

When the density of the AlN sintered body thus obtained was measured by the Archimedes method, it was 3.29 g / cm ³ and was sufficiently densified. A part of this sintered body was cut out, mirror-polished, and then observed by SEM to measure the average particle diameter of AlN, which was 1.7 μm. Also, the diameter from this sintered body
A disk with a thickness of 10 mm and a thickness of 3 mm was cut out and its thermal conductivity was measured by the laser flash method at room temperature of 293K ± 2K.
It was 45 W / m K. Further, when a constituent phase was evaluated by X-ray diffraction after crushing a part of the sintered body, constituent phases other than AlN were Y ₄ Al ₂ O ₉ , YAlO ₃ and a trace amount of unidentified phase.

Example 2 The average primary particle size was 0.9 μm, and the amount of impurity oxygen was 1.3 weight.
% AlN powder 95% by weight, average particle size 0.3 μm
4% by weight of YF ₃ powder having a purity of 99.9% and an average particle diameter of 0.1.
CaCO ₃ powder with 4 μm and 99.9% purity is converted to CaO 1
% By weight, crushed using a ball mill and mixed to prepare a raw material powder.

Subsequently, 7 wt% of an acrylic binder was added to the above raw material powder to granulate, and the granulated powder was added to 50 MPa.
It was molded under uniaxial pressure to obtain a green compact. This green compact was heated to 973 K in a nitrogen gas atmosphere to remove the acrylic binder. This binder-removed body was set in a firing vessel consisting of an AlN ceramics plate and an AlN ring, and it was heated in an electric resistance furnace using a rod-shaped molybdenum heater and an oxide furnace material containing 99.8% Al ₂ O _3. 182 at temperature rate 1000K / h
The temperature was raised to 3K and the temperature was maintained for 6 hours for sintering. The amount of oxygen in the atmosphere during firing was 100 ppm or less.

When the density of the obtained AlN sintered body was measured by the Archimedes method, it was 3.29 g / cm ³ and was sufficiently densified. After cutting out a part of this sintered body and mirror-polishing it,
When the average particle diameter of AlN was measured by SEM observation,
It was 1.6 μm. The thermal conductivity of this sintered body was measured in the same manner as in Example 1, and it was 136 W / m K. Further, when a constituent phase was evaluated by X-ray diffraction after crushing a part of the sintered body, constituent phases other than AlN were found to be Y ₄ Al ₂
O ₉ , YAlO ₃ and a trace amount of unidentified phase.

Example 3 The average primary particle size was 0.6 μm, and the amount of impurity oxygen was 1.3 weight.
% AlN powder 95% by weight, average particle size 0.3 μm
, Purity 99.9% by weight of Y ₂ O ₃ powder 3 wt%, CaF
₂ is 1% by weight, MnO ₂ is 0.25% by weight, and TiO ₂ is 0.5%.
% By weight, 0.25% by weight of AlPO _4, and an organic binder such as an acrylic resin, which is easily decomposed in a non-oxidizing atmosphere, and an alcohol-based solvent, etc. are added and thoroughly mixed,
A slip with a viscosity of about 5000 cps was prepared. This slip was formed into a sheet having a uniform thickness of about 0.3 mm by the doctor blade method.

The above-mentioned sheet was cut into a desired size, and a via hole for obtaining an electrical connection between the layers was formed. The via hole was filled with W paste using W powder having an average primary particle diameter of 0.8 μm by a press-fitting method. Further, a desired conductor circuit was formed on the sheet having the via holes by W paste by the screen printing method. A desired number of the thus obtained sheets were laminated and integrated by hot pressing. Then, it was cut into a required shape and heated to 973 K in a non-oxidizing atmosphere such as nitrogen to remove the binder. After the binder removal treatment, it is set in a sintering container composed of an AlN ceramic plate and an Al ₂ O ₃ ring, and nitrogen is removed using an electric resistance furnace using a mesh-shaped tungsten heater and oxide furnace material. Simultaneous firing was performed under the conditions of 1723K × 5 hours in the atmosphere. The amount of oxygen in the atmosphere during firing was 100 ppm or less.

According to SEM observation, the obtained AlN package was sufficiently densified in both the AlN layer and the W layer, and the average particle diameter of the AlN crystal grains of the obtained AlN package was 0.9 μm. Average particle size is 1.2 μm
Met. Further, when the mixed region at the interface between the AlN layer and the W layer was examined by SEM, it was 1.4 μm.

Comparative Example 1 The average primary particle size is 1.3 μm, and the amount of impurity oxygen is 0.9 weight.
% AlN powder 97% by weight, average particle size 0.2 μm
Using the raw material powder to which 3% by weight of Y ₂ O ₃ having a purity of 99.9% was added, the process of removing the binder was performed in the same manner as in Example 1,
The binder-removed body was placed in an AlN sintering container, and a sintering furnace using a graphite heater and graphite furnace material was used.
Sintering was performed in a nitrogen atmosphere at 2073K for 3 hours.

The density, average particle size, thermal conductivity and constituent phases of the obtained AlN sintered body were measured and evaluated in the same manner as in Example 1. The density was 3.31 g / cm ³ , the average particle size was 6.4 μm, and the thermal The conductivity is 190 W / m K, and the constituent phases other than AlN are Y ₄ Al ₂ O ₉
And YAlO ₃ , but the manufacturing cost of the AlN sintered body was significantly higher than that of Example 1.

Comparative Example 2 An AlN sintered body material having the same composition as in Comparative Example 1 was sintered in the same manner as in Comparative Example 1 except that the sintering conditions were changed to 1823K × 3 hours. The density, average particle size, thermal conductivity, and constituent phases of the obtained AlN sintered body were measured and evaluated in the same manner as in Example 1. The density was 2.1 g / cm ³ , which was not sufficiently densified, and the average The particle size was 0.6 μm, the thermal conductivity was 15 W / m K, and the constituent phases other than AlN were Y ₄ Al ₂ O ₉ and Y ₂ O ₃ .

Comparative Example 3 An AlN sintered body was produced in the same manner as in Example 1 except that an Al ₂ O ₃ ring containing 6% by weight of SiO ₂ was used as the sintering container. When the thermal conductivity of the obtained AlN sintered body was measured in the same manner as in Example 1, it was as low as 95 W / m K.

Example 4 The amount of impurity oxygen was 1.3% by weight, and the average primary particle size was 0.8 μm.
5% by weight of Y ₂ O ₃ , 1.0% by weight of CaCO ₃ in terms of CaO, and LaB _{6 with} respect to 95.45% by weight of mN AlN powder.
Was added in an amount of 0.25% by weight, and WO3 was added in an amount of 0.3% by weight in terms of W.
This mixed powder was mixed with a ball mill using n-butanol as a dispersion medium. After removing the n-butanol, the acrylic binder dispersed in xylene was
It was added so that it would be wt%, and once made into a paste, xylene was removed. The obtained powder was passed through a mesh having an opening of 0.5 mm to give a granulated powder.

This granulated powder was molded into a block shape under a pressure of 50 MPa, and then heated to a maximum temperature of 773 K in a dry gas having an air composition to remove the binder. This binder removal body is
It was set without a lid in a firing container consisting of an N ceramics plate and an alumina ring. The rod-shaped tungsten heater part and the sintering container were shielded by the furnace material containing Al ₂ O ₃ as a main component, containing 0.6% by weight of MgO, and having an SiO ₂ amount of 0.5% by weight, and volatilized from the heater. Temperature rise rate by using an electric resistance furnace that prevents the material from directly contacting the sintered body.
The temperature was raised to 1873 K at 500 K / h, and this temperature was maintained for 4 hours for sintering.

The density, average particle size, thermal conductivity, and constituent phases of the obtained AlN sintered body were measured and evaluated in the same manner as in Example 1, and the density was 3.29 g / cm ³ and was sufficiently densified. ,
The average particle size is 1.7 μm, the thermal conductivity is 155 W / m K, and the constituent phases other than AlN are Y ₄ Al ₂ O ₉ and YAlO ₃
And a trace amount of unidentified phase.

[0043]

As described above, according to the method for producing an aluminum nitride sintered body of the present invention, the heat dissipation is sufficiently excellent as compared with alumina ceramics and the like, 100 to 180 W / m
An aluminum nitride sintered body having a thermal conductivity of K can be stably manufactured at a low cost by a method suitable for mass production. Therefore, it is possible to significantly reduce the manufacturing costs of the aluminum nitride sintered body and the circuit board or package base body using the aluminum nitride sintered body.

[0044]

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Fumio Ueno 1 Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa Incorporated Toshiba Research and Development Center

Claims (1)

[Claims] 1. An electric resistance furnace having a metal heater and an oxide furnace material, wherein an aluminum nitride sintered body raw material having a low-temperature sintering composition is supplied in a nitrogen or argon atmosphere in which the amount of oxygen present is 100 ppm or less. And has a thermal conductivity of 100 to 1 characterized by being fired at a temperature of 1873K or less.
Manufacturing method of 80W / m K aluminum nitride sintered body.