JPS63265866A - Production of aluminum nitride sintered body - Google Patents
Production of aluminum nitride sintered bodyInfo
- Publication number
- JPS63265866A JPS63265866A JP62099995A JP9999587A JPS63265866A JP S63265866 A JPS63265866 A JP S63265866A JP 62099995 A JP62099995 A JP 62099995A JP 9999587 A JP9999587 A JP 9999587A JP S63265866 A JPS63265866 A JP S63265866A
- Authority
- JP
- Japan
- Prior art keywords
- cyanamide
- aluminum nitride
- sintered body
- powder
- sintering
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- PMHQVHHXPFUNSP-UHFFFAOYSA-M copper(1+);methylsulfanylmethane;bromide Chemical compound Br[Cu].CSC PMHQVHHXPFUNSP-UHFFFAOYSA-M 0.000 title claims description 43
- 238000004519 manufacturing process Methods 0.000 title claims description 12
- 239000000843 powder Substances 0.000 claims abstract description 29
- 239000000203 mixture Substances 0.000 claims abstract description 14
- 239000012298 atmosphere Substances 0.000 claims abstract description 11
- 238000000465 moulding Methods 0.000 claims abstract description 9
- 238000002156 mixing Methods 0.000 claims abstract description 6
- 238000010304 firing Methods 0.000 claims description 19
- IJGRMHOSHXDMSA-UHFFFAOYSA-N nitrogen Substances N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 19
- XDOQMROXMLWOHR-UHFFFAOYSA-N [Ba].NC#N Chemical compound [Ba].NC#N XDOQMROXMLWOHR-UHFFFAOYSA-N 0.000 claims description 12
- DVYGXKGHCJURII-UHFFFAOYSA-N cyanamide;strontium Chemical compound [Sr].NC#N DVYGXKGHCJURII-UHFFFAOYSA-N 0.000 claims description 12
- GOKQBRXJUKTYSC-UHFFFAOYSA-N magnesium;azanidylidenemethylideneazanide Chemical compound [Mg+2].[N-]=C=[N-] GOKQBRXJUKTYSC-UHFFFAOYSA-N 0.000 claims description 12
- 229910052757 nitrogen Inorganic materials 0.000 claims description 8
- MVXMNHYVCLMLDD-UHFFFAOYSA-N 4-methoxynaphthalene-1-carbaldehyde Chemical compound C1=CC=C2C(OC)=CC=C(C=O)C2=C1 MVXMNHYVCLMLDD-UHFFFAOYSA-N 0.000 claims description 6
- 230000001590 oxidative effect Effects 0.000 claims description 4
- QJGQUHMNIGDVPM-UHFFFAOYSA-N nitrogen group Chemical group [N] QJGQUHMNIGDVPM-UHFFFAOYSA-N 0.000 claims 1
- 238000000034 method Methods 0.000 abstract description 40
- 238000005245 sintering Methods 0.000 abstract description 38
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 abstract description 9
- 239000001301 oxygen Substances 0.000 abstract description 9
- 229910052760 oxygen Inorganic materials 0.000 abstract description 9
- 229910052712 strontium Inorganic materials 0.000 abstract description 7
- 229910052788 barium Inorganic materials 0.000 abstract description 6
- 238000001354 calcination Methods 0.000 abstract description 4
- 229910052791 calcium Inorganic materials 0.000 abstract description 4
- XZMCDFZZKTWFGF-UHFFFAOYSA-N Cyanamide Chemical compound NC#N XZMCDFZZKTWFGF-UHFFFAOYSA-N 0.000 abstract description 2
- 150000001912 cyanamides Chemical class 0.000 abstract 5
- 238000012856 packing Methods 0.000 abstract 2
- 239000000463 material Substances 0.000 description 8
- -1 calcium nitride Chemical class 0.000 description 7
- 239000000758 substrate Substances 0.000 description 7
- 239000002245 particle Substances 0.000 description 6
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 5
- 239000007789 gas Substances 0.000 description 5
- 238000001272 pressureless sintering Methods 0.000 description 5
- 239000003125 aqueous solvent Substances 0.000 description 4
- 239000011575 calcium Substances 0.000 description 4
- 229910052799 carbon Inorganic materials 0.000 description 4
- 238000000354 decomposition reaction Methods 0.000 description 4
- 229910001873 dinitrogen Inorganic materials 0.000 description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 3
- 238000005520 cutting process Methods 0.000 description 3
- 238000010292 electrical insulation Methods 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 238000010298 pulverizing process Methods 0.000 description 3
- 229910052710 silicon Inorganic materials 0.000 description 3
- 239000010703 silicon Substances 0.000 description 3
- 239000000654 additive Substances 0.000 description 2
- UIXRSLJINYRGFQ-UHFFFAOYSA-N calcium carbide Chemical compound [Ca+2].[C-]#[C-] UIXRSLJINYRGFQ-UHFFFAOYSA-N 0.000 description 2
- 238000004891 communication Methods 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000017525 heat dissipation Effects 0.000 description 2
- 239000011261 inert gas Substances 0.000 description 2
- 239000012071 phase Substances 0.000 description 2
- 238000005498 polishing Methods 0.000 description 2
- 239000004065 semiconductor Substances 0.000 description 2
- IATRAKWUXMZMIY-UHFFFAOYSA-N strontium oxide Chemical compound [O-2].[Sr+2] IATRAKWUXMZMIY-UHFFFAOYSA-N 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 150000000476 acetylides Chemical class 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 229910052784 alkaline earth metal Inorganic materials 0.000 description 1
- HSFWRNGVRCDJHI-UHFFFAOYSA-N alpha-acetylene Natural products C#C HSFWRNGVRCDJHI-UHFFFAOYSA-N 0.000 description 1
- 229910052785 arsenic Inorganic materials 0.000 description 1
- RQNWIZPPADIBDY-UHFFFAOYSA-N arsenic atom Chemical compound [As] RQNWIZPPADIBDY-UHFFFAOYSA-N 0.000 description 1
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- AXCZMVOFGPJBDE-UHFFFAOYSA-L calcium dihydroxide Chemical compound [OH-].[OH-].[Ca+2] AXCZMVOFGPJBDE-UHFFFAOYSA-L 0.000 description 1
- 229910001861 calcium hydroxide Inorganic materials 0.000 description 1
- 235000011116 calcium hydroxide Nutrition 0.000 description 1
- 239000000920 calcium hydroxide Substances 0.000 description 1
- 229910002091 carbon monoxide Inorganic materials 0.000 description 1
- 229910002090 carbon oxide Inorganic materials 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000013626 chemical specie Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000011362 coarse particle Substances 0.000 description 1
- 238000005238 degreasing Methods 0.000 description 1
- 125000002534 ethynyl group Chemical group [H]C#C* 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 238000000227 grinding Methods 0.000 description 1
- 230000020169 heat generation Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000001513 hot isostatic pressing Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 239000002075 main ingredient Substances 0.000 description 1
- 239000011812 mixed powder Substances 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
Landscapes
- Ceramic Products (AREA)
Abstract
Description
【発明の詳細な説明】
[産業上の利用分野]
本発明は窒化アルミニウム焼結体、特に高熱伝導性の窒
化アルミニウム焼結体の製造方法に関する。DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing an aluminum nitride sintered body, particularly a highly thermally conductive aluminum nitride sintered body.
[従来の技術]
近年、電子機器の高速・高性能化、小型・軽量化が進む
中で半導体素子の単位面積当たりの発熱量が大幅に増加
し、この発熱のために半導体素子の正常な動作が妨げら
れる問題が生じ始めている。[Prior art] In recent years, as electronic devices have become faster, more sophisticated, smaller, and lighter, the amount of heat generated per unit area of semiconductor devices has increased significantly, and this heat generation has made it difficult for semiconductor devices to operate properly. Problems are starting to arise that are hindering this.
特に、高密度実装置C,LS I、VLS I 、マイ
クロ波通信及び光通信用のマイクロウェーブ用トランジ
スタ、レーザーダイオード等では熱伝導性の高い絶縁性
基板材料の要求が強い。In particular, there is a strong demand for insulating substrate materials with high thermal conductivity in high-density actual devices C, LSI, VLSI, microwave transistors for microwave communication and optical communication, laser diodes, and the like.
従来、絶縁性基板材料には一般にアルミナ焼結体が多く
用いられているが、最近の絶縁性基板材料としてはアル
ミナ基板では熱の放散性(熱伝導性)が悪く、熱膨張係
数もシリコンに比べて大きすぎる。このため、熱放散性
が良好な絶縁性基板材料の開発が要求されている。Traditionally, alumina sintered bodies have been commonly used as insulating substrate materials, but as for recent insulating substrate materials, alumina substrates have poor heat dissipation (thermal conductivity) and a thermal expansion coefficient that is lower than that of silicon. Too big in comparison. Therefore, there is a need to develop an insulating substrate material with good heat dissipation properties.
このような絶縁性基板材料としては
■熱伝導性が良い(熱伝導率が大きい):■電気絶縁性
が大きい;
■熱膨張係数がシリコンに近い;
■機械的強度が大きい、
等の特性が要求される。Such insulating substrate materials have the following characteristics: ■ Good thermal conductivity (high thermal conductivity); ■ High electrical insulation; ■ The coefficient of thermal expansion is close to that of silicon; ■ High mechanical strength. required.
ところで、熱伝導性の高い基板材料として有望視されて
いる窒化アルミニウムは熱膨張係数が約4.3 X 1
0−’/”Cでアルミナ焼結体の約7×10−’/’C
に比べて小さく、シリコンの熱膨張係数的3.5X10
’−17℃に近い。また、機械的強度も曲げ強さで約5
0 kg/ mi2とアルミナ焼結体の約20kg/m
m’に比べて高強度であることが知られている。更に、
電気抵抗が10+4Ωchi以上と電気絶縁性にも優れ
た材料である。その他、絶縁耐圧、誘電率等もアルミナ
焼結体の緒特性と同等もしくはそれ以上であるため、窒
化アルミニウム焼結体が鋭意研究開発されている。By the way, aluminum nitride, which is seen as a promising substrate material with high thermal conductivity, has a coefficient of thermal expansion of approximately 4.3 x 1.
Approximately 7×10-'/'C of alumina sintered body at 0-'/'C
It is smaller than 3.5X10 due to the coefficient of thermal expansion of silicon.
'Close to -17℃. In addition, the mechanical strength is approximately 5 in terms of bending strength.
0 kg/mi2 and about 20 kg/m of alumina sintered body
It is known to have higher strength than m'. Furthermore,
It is a material with excellent electrical insulation properties, with an electrical resistance of 10+4 Ωchi or more. In addition, aluminum nitride sintered bodies are being actively researched and developed because their dielectric strength, dielectric constant, and other properties are equal to or higher than those of alumina sintered bodies.
し発明が解決しようとする問題点コ
しかし、窒化アルミニウムは難焼結性物質であるため、
単体では常圧焼結した場合には緻密な焼結体を得ること
が困難である。そのため、加圧・加熱を伴うホットプレ
ス法、ガス加圧法、HIP法による焼結体の製造法や各
種化合物を焼結助剤として添加した常圧焼結による焼結
体の製造法が検討されている。これらの製造法の中で常
圧焼結法は大量生産に向いているので望ましい焼結体の
製造方法である0例えば特開昭54−100410号公
報には酸化カルシウム(CaO〉、酸化バリウム(Ba
d)、酸化ストロンチウム(S ro )等を焼結助剤
として添加する窒化アルミニウム焼結体の製造方法を開
示している。しかし、この方法では得られる窒化アルミ
ニウム焼結体の熱伝導率は50〜60W/mKと低く、
更に高い熱伝導率を有する窒化アルミニウム焼結体の製
造方法が探求されている。However, since aluminum nitride is a material that is difficult to sinter,
When used alone, it is difficult to obtain a dense sintered body when sintered under normal pressure. For this reason, methods for producing sintered bodies using hot press methods, gas pressurization methods, and HIP methods that involve pressure and heating, as well as methods for producing sintered bodies using pressureless sintering with the addition of various compounds as sintering aids, have been investigated. ing. Among these manufacturing methods, the pressureless sintering method is suitable for mass production and is therefore a preferred method for manufacturing sintered bodies. Ba
d) discloses a method for producing an aluminum nitride sintered body in which strontium oxide (S ro ) or the like is added as a sintering aid. However, the thermal conductivity of the aluminum nitride sintered body obtained by this method is as low as 50 to 60 W/mK.
A method of manufacturing an aluminum nitride sintered body having even higher thermal conductivity is being sought.
また、特開昭60−151280号公報には、添加剤と
してCa、 Sr、 BJI等のアセチリド化合物を加
える方法が、また、特開昭60−188478号公報に
はCa3 N 2、M93N2.5rsNz、BJI3
N、を焼結補助剤として添加し、窒化アルミニウムを焼
結する方法が開示されている。しかし、これらの方法で
は焼結助剤として使用される化合物が空気中で非常に不
安定である0例えば、特開昭60−151280号公報
のカルシウムアセチリドは水と激しく反応し、アセチレ
ンガスを放出するため、空気中では爆発の危険性がある
。更に、粒度150メツシユ以下のカルシウムアセチリ
ドを空気中に1時間放置すると、全てCa(OH)2に
分解してしまい、取り扱いに注意を要する。また、焼結
助剤が焼結体に残り易く、電気絶縁性が若干劣る傾向に
ある。また、特開昭60−186478号公報に開示さ
れた窒化カルシウム(平均粒径3μ)に至っては空気に
触れると瞬時にCa(OH)zに分解してしまう、この
欠点は空気または水の存在しない状態で取り扱えば克服
できそうに思われるが、実際には基板製造の各工程(粉
砕、混合、成形、脱脂、焼成)中に分解を防止すること
は大きな困難を伴い、特別な工夫を施すことによりコス
ト高となる。In addition, JP-A-60-151280 describes a method of adding acetylide compounds such as Ca, Sr, and BJI as additives, and JP-A-60-188478 describes a method of adding Ca3N2, M93N2.5rsNz, BJI3
A method of sintering aluminum nitride by adding N as a sintering aid is disclosed. However, in these methods, the compound used as a sintering aid is very unstable in the air. For example, calcium acetylide in JP-A-60-151280 reacts violently with water and releases acetylene gas. Therefore, there is a risk of explosion in the air. Furthermore, if calcium acetylide with a particle size of 150 mesh or less is left in the air for one hour, it will completely decompose into Ca(OH)2, so care must be taken when handling it. In addition, the sintering aid tends to remain on the sintered body, and the electrical insulation properties tend to be slightly inferior. Furthermore, calcium nitride (average particle size 3μ) disclosed in JP-A-60-186478 instantly decomposes into Ca(OH)z when it comes into contact with air.This drawback is due to the presence of air or water. Although it seems possible to overcome this problem by handling the product without sacrificing it, in reality it is very difficult to prevent decomposition during each process of board manufacturing (pulverization, mixing, molding, degreasing, and baking), and special measures must be taken. This increases costs.
前記のホットプレス法やHIP法は複雑形状品大型成形
品の製造が困難で生産性が低く、しかもかなりコストが
高くなるという欠点があるにれに対して、常圧焼結法は
前述のように量産化が容易で且つ低コスト化が可能であ
るが、次に示すような欠点があった。常圧焼結法で用い
られる焼結助剤は特公昭61−28629号公報に見ら
れるように、一般に高温での蒸気圧が比較的高く、焼結
時に粉末成形体の表面付近の焼結助剤が蒸発・揮散する
。そのため、焼結体の表面付近が緻密化しなったり、形
状によっては焼結体が大幅に変形するという欠点があっ
た。特に、添加剤と巳てアルカリ土頭金属を用いた場合
には、変形が顕著であり、また、焼結体の形状が平板状
のように体積当たりの表面積が大きい程、顕著である。The above-mentioned hot press method and HIP method have the drawbacks of difficulty in producing large molded products with complex shapes, low productivity, and considerably high costs, whereas the pressureless sintering method Although it is easy to mass-produce and can reduce costs, it has the following drawbacks. As seen in Japanese Patent Publication No. 61-28629, the sintering aids used in the pressureless sintering method generally have a relatively high vapor pressure at high temperatures, and the sintering aids near the surface of the powder compact during sintering. The agent evaporates and volatilizes. As a result, the vicinity of the surface of the sintered body becomes less dense, and depending on the shape, the sintered body may be significantly deformed. In particular, when an alkali earth metal is used instead of an additive, the deformation is significant, and the deformation is more significant as the sintered body has a larger surface area per volume, such as a flat plate shape.
このため、焼結後の寸法精度が良くなく、表面の焼けて
いない部分を切断や研摩などの加工により寸法の調整や
表面平滑性等を調整する必要がある。′iな、焼結体密
度があがっていない部分も残るので、熱伝導率の良い焼
結体が得られにくい。For this reason, the dimensional accuracy after sintering is not good, and it is necessary to adjust the dimensions, surface smoothness, etc. by cutting, polishing, or other processing on the unsintered portions of the surface. Since some parts remain where the density of the sintered body has not increased, it is difficult to obtain a sintered body with good thermal conductivity.
[問題点を解決するための手段]
従って、本発明は窒化アルミニウム粉末に、マグネシウ
ムシアナミド、ストロンチウムシアナミド及び/または
バリウムシアナミドまたはカルシウムシアナミドとマグ
ネシウムシアナミド、ストロンチウムシアナミド及び/
またはバリウムシアナミドを添加・混合し、得られた混
合物を成形し、得られた成形体を窒化アルミニウム粉末
にマグネシウムシアナミド、ストロンチウムシアナミド
及び/またはバリウムシアナミドまたはカルシウムシア
ナミドとマグネシウムシアナミド、ストロンチウムシア
ナミド及び/またはバリウムシアナミドを添加してなる
つめ粉で覆い焼成するが、または得られた成形体を非酸
化性雰囲気中で焼成するか、またはそれら両者を同時に
行なうことを特徴とする窒化アルミニウム焼結体の製造
方法を提供するにある。[Means for Solving the Problems] Therefore, the present invention provides aluminum nitride powder with magnesium cyanamide, strontium cyanamide and/or barium cyanamide, or calcium cyanamide and magnesium cyanamide, strontium cyanamide and/or barium cyanamide.
Alternatively, barium cyanamide is added and mixed, the resulting mixture is molded, and the resulting molded body is mixed with aluminum nitride powder and magnesium cyanamide, strontium cyanamide and/or barium cyanamide, or calcium cyanamide and magnesium cyanamide, strontium cyanamide and/or barium. A method for producing an aluminum nitride sintered body, characterized by adding cyanamide and covering it with nail powder and firing it, or firing the obtained molded body in a non-oxidizing atmosphere, or both at the same time. is to provide.
[作 用コ
窒化アルミニウム焼結体中の酸素及び粒界はフォノン散
乱の原因となり、熱伝導度を低下させる。[Operation] Oxygen and grain boundaries in the co-aluminum nitride sintered body cause phonon scattering and reduce thermal conductivity.
そこで、焼結時に酸素を系外に除去して熱伝導度の向上
を図る0本発明方法では焼結助剤としてM9、S(Ba
のシアナミド化合物を用いる。これらはマグネシウムシ
アナミド、ストロンチウムシアナミド及び/またはバリ
ウムシアナミドまたはカルシウムシアナミドとマグネシ
ウムシアナミド、ストロンチウムシアナミド及び/また
はバリウムシアナミドとして単独または併用することが
できる。Therefore, in the method of the present invention, which aims to improve thermal conductivity by removing oxygen from the system during sintering, M9, S (Ba
cyanamide compound is used. These can be used alone or in combination as magnesium cyanamide, strontium cyanamide and/or barium cyanamide, or calcium cyanamide and magnesium cyanamide, strontium cyanamide and/or barium cyanamide.
上述のシアナミド化合物は焼結時に金属、炭素、窒素に
容易に分解する。The above-mentioned cyanamide compound easily decomposes into metal, carbon, and nitrogen during sintering.
MCN2→M + C十N 2 (式中、Mは金属を表
す)このうち、炭素が酸素と反応してCOまたはC○2
ガスとして成形体の外へ除去され、また、金属が酸素を
トラップして液相焼結により成形体が緻密化され、更に
十分焼結することにより粒界相が易蒸発性のため窒化ア
ルミニウム焼結体中から飛散すると共に窒化アルミニウ
ム粒子が成長して不純物の原因ともなる粒界相がほとん
ど消滅して高熱伝導性の窒化アルミニウム焼結体が得ら
れる。MCN2→M + C0N2 (In the formula, M represents a metal) Among these, carbon reacts with oxygen to form CO or C○2
The metal traps oxygen and densifies the compact through liquid phase sintering.Aluminum nitride sintering occurs because the grain boundary phase is easily evaporated due to sufficient sintering. Aluminum nitride particles grow as they scatter from the compact, and the grain boundary phase that causes impurities almost disappears, resulting in a highly thermally conductive aluminum nitride sintered body.
以下、本発明について具体的に説明する。The present invention will be specifically explained below.
本発明方法は窒化アルミニウム粉末に焼結助剤としてM
g、Sr、Baのシアナミド化合物の少なくとも1種ま
たはそれらとCaのシアナミド化合物を添加することに
より、焼成時に成形体中の酸素量を低減することができ
、この結果として、窒化アルミニウム焼結体の熱伝導度
を著しく増大させることができる。特に、上述のような
焼結助剤の合計添加量を0,01〜7重量%にすること
により焼結体密度も上昇し、熱伝導率も60W/mK(
室温)以上と従来の窒化アルミニウム焼結体より大きな
値が得られる。焼結助剤の添加量がSr、Baのシアナ
ミド化合物の場合7重量%を超えると、急激に焼結体の
密度が下がり、熱伝導率が低下するために好ましくない
。焼結助剤が過剰になると反応に寄与しない炭素が窒化
アルミニウムの粒間に残留し、焼結を阻害するものと思
われる。The method of the present invention uses M as a sintering aid in aluminum nitride powder.
By adding at least one cyanamide compound of g, Sr, and Ba or a cyanamide compound of these and Ca, the amount of oxygen in the compact can be reduced during firing, and as a result, the amount of oxygen in the aluminum nitride sintered compact is reduced. Thermal conductivity can be significantly increased. In particular, by increasing the total amount of sintering aids added to 0.01 to 7% by weight, the density of the sintered body increases and the thermal conductivity also increases to 60 W/mK (
(room temperature) or higher, which is larger than that of conventional aluminum nitride sintered bodies. If the amount of the sintering aid added exceeds 7% by weight in the case of a cyanamide compound of Sr or Ba, it is not preferable because the density of the sintered body decreases rapidly and the thermal conductivity decreases. It is thought that when the sintering aid is used in excess, carbon that does not contribute to the reaction remains between the grains of aluminum nitride and inhibits sintering.
本発明に使用する焼結助剤は空気中の水分と反応し、徐
々に酸化物に変化するが、非水溶媒中では安定であり、
焼結助剤添加後の混合・粉砕操作では非水溶媒中で行な
うことが望ましい。The sintering aid used in the present invention reacts with moisture in the air and gradually changes into an oxide, but is stable in non-aqueous solvents.
The mixing and pulverizing operations after adding the sintering aid are preferably carried out in a non-aqueous solvent.
混合・粉砕時間は原料粉末の粒度により異なり、数時間
から数十時間を要している。この際、非水溶媒を使用す
る場合には、混合・粉砕後、非水溶媒を真空または減圧
下で加熱・乾燥することが迅速で望ましい。The mixing and grinding time varies depending on the particle size of the raw material powder, and takes from several hours to several tens of hours. At this time, when a non-aqueous solvent is used, it is desirable to quickly heat and dry the non-aqueous solvent under vacuum or reduced pressure after mixing and pulverizing.
得られた混合粉体を室温で加圧プレスして所定の形状に
成形し、最後に窒素ガス、水素ガス、−酸化炭素ガス・
不活性ガスまたは真空雰囲気のような非酸化性雰囲気中
で高温焼成を行なう、M4ヒ性雰囲気中で焼成すると、
窒化アルミニウムが酸化してしまい、緻密な焼結体が得
られない。The obtained mixed powder is press-pressed at room temperature to form a predetermined shape, and finally nitrogen gas, hydrogen gas, carbon oxide gas,
When fired in an M4 arsenic atmosphere, where high temperature firing is performed in a non-oxidizing atmosphere such as an inert gas or vacuum atmosphere,
Aluminum nitride is oxidized and a dense sintered body cannot be obtained.
焼成は1500〜2200℃の温度範囲で行なうことが
でき、1600〜2100℃の温度範囲が特に好適であ
るが、温度範囲はこれらに限定されるものではないこと
を理解されたい。It should be understood that the calcination can be carried out at a temperature range of 1500-2200<0>C, with a temperature range of 1600-2100<0>C being particularly preferred, although the temperature range is not limited thereto.
また、焼成時間は焼成温度等に依存して種々変化させる
ことができる。Further, the firing time can be varied depending on the firing temperature and the like.
本発明方法に使用する焼成方法は常圧焼結法でも、加圧
焼結法であってもよい、加圧焼結法としてはホットプレ
ス法、ガス加圧法、HIP法(熱間静水圧加圧焼結法)
などを使用することができる。特に、ホットプレス法を
使用して焼成すると、高熱伝導性窒化アルミニウム焼結
体を得ることができる。The firing method used in the method of the present invention may be an ordinary pressure sintering method or a pressure sintering method. Examples of the pressure sintering method include a hot press method, a gas pressurization method, and a HIP method (hot isostatic pressing method). pressure sintering method)
etc. can be used. In particular, when fired using a hot press method, a highly thermally conductive aluminum nitride sintered body can be obtained.
しかし、前記ホットプレス法は生産性が低く、しかもコ
スト高となる欠点がある。これに対して常圧焼結法の方
が量産化が容易で且つ低コストであるが、焼成時に成形
体の表面付近の焼結助剤が分散・揮散するため、焼結体
表面付近の緻密化が若干劣ったり、焼結体の形状によっ
てはかなり変形が見られる。それ故、焼結後の寸法精度
が良くないこともあり、そのような場合には、切断や研
摩などの加工により寸法の調整や表面の平滑性等を調整
する必要がある。However, the hot press method has the drawbacks of low productivity and high cost. On the other hand, the pressureless sintering method is easier to mass-produce and is less expensive, but because the sintering aid near the surface of the compact is dispersed and volatilized during firing, it The sintered body may be slightly deformed, or may be considerably deformed depending on the shape of the sintered body. Therefore, the dimensional accuracy after sintering may not be good, and in such cases, it is necessary to adjust the dimensions and the smoothness of the surface by processing such as cutting or polishing.
そこで、上述の成形体分焼成する際に、成形体と同組成
もしくはそれに近い組成の粉末(つめ粉)を使用して該
成形体を覆った後、上記と同様の焼成条件で常圧焼成す
ることができる。つめ粉の組成としては主剤として窒化
アルミニウム粉末を用い、成形体中に添加した焼結助剤
の化学種と同じ化学種を添加する。その添加量は成形体
の組成よりやや過剰から同組成もしくは極小量であって
もよい、しかし、大過剰に添加した場合だけは焼結助剤
の濃度が濃くなり過ぎ、かえって焼結を阻害するため、
得られる焼結体が多孔質になってしまうために好ましく
ない、つめ粉の粒度は特に限定されるものではないが、
成形体の形状が比較的複雑な場合または焼結時の変形を
特に抑える場合には、比較的細かい粒径のつめ粉を用い
ることが望ましい、ただし、細か過ぎると、つめ粉同志
が強固に焼結したり、焼結体に固着することがあり好ま
しくない、一方、成形体の形状が単純な場合には、粗い
粒子の方がつめ粉が固着しに<<、焼成中に不必要な粒
界が焼結体から飛散し易いので好ましい。Therefore, when firing the above-mentioned molded body, the molded body is covered with powder (nail powder) having the same composition or a composition similar to that of the molded body, and then fired under normal pressure under the same firing conditions as above. be able to. As for the composition of the nail powder, aluminum nitride powder is used as the main ingredient, and the same chemical species as the sintering aid added to the compact is added. The amount added may be slightly excess to the same composition as the composition of the molded body, or a very small amount. However, if it is added in large excess, the concentration of the sintering aid will become too high, which will actually inhibit sintering. For,
The particle size of the nail powder is not particularly limited, although it is not preferable because the resulting sintered body becomes porous.
When the shape of the compact is relatively complex or when deformation during sintering is to be particularly suppressed, it is desirable to use a relatively fine nail powder. However, if the particle size is too fine, the nail powder may sinter firmly together. On the other hand, if the shape of the compact is simple, coarse particles will prevent nail powder from sticking to the sintered body, which is undesirable. This is preferable because the field easily scatters from the sintered body.
上述の焼成方法と同様の目的で、上記成形体を常圧以上
50kg/am2の窒素圧の窒素または窒素と不活性ガ
スの混合ガス中で焼成するものである。For the same purpose as the firing method described above, the molded body is fired in nitrogen or a mixed gas of nitrogen and an inert gas at a nitrogen pressure of 50 kg/am2 above normal pressure.
この方法も焼結助剤の分解・揮散を抑制するために行な
われるものであるが、窒素圧の低い方では若干の変形を
生ずることもあるが、焼結助剤の分解・飛散を充分に抑
制することができ、窒化アルミニウム焼結体の変形量を
かなり少なくすることができる。肱な、この方法は上述
の方法のように成形体を覆うつめ粉が窒化アルミニウム
焼結体に固着してしまうような心配は全くない、しかし
、窒素圧が50 kg/c、2を超えても、焼結助剤の
分解・飛散を抑制する効果は余り改善されず、装置的な
困難が付随するために好ましくない。This method is also used to suppress the decomposition and volatilization of the sintering aid, but although some deformation may occur at low nitrogen pressures, it is sufficient to prevent the decomposition and scattering of the sintering aid. Therefore, the amount of deformation of the aluminum nitride sintered body can be considerably reduced. However, unlike the method described above, this method does not have to worry about the nail powder covering the compact sticking to the aluminum nitride sintered compact. However, if the nitrogen pressure exceeds 50 kg/c, 2 However, the effect of suppressing the decomposition and scattering of the sintering aid is not improved much, and it is not preferable because it is accompanied by equipment difficulties.
上述の焼成手段は成形体の形状、得られる窒化アルミニ
ウム焼結体の用途等に応じて適宜選択することができる
。The above-mentioned firing means can be appropriately selected depending on the shape of the compact, the use of the resulting aluminum nitride sintered body, and the like.
[実 施 例] 以下に実施例を挙げ、本発明を更に説明する。[Example] The present invention will be further explained with reference to Examples below.
え1鮭支
本実施例では下記の第1表に記載する組成をもつ混合物
を2トン/cII2の成形圧で成形し、得られた成形体
を窒素ガス雰囲気中1850℃で2時間常圧焼成するこ
とにより窒化アルミニウム焼結体を得た。得られた窒化
アルミニウム焼結体の特性を第1表に併記する。E1 Salmon Branch In this example, a mixture having the composition shown in Table 1 below was molded at a molding pressure of 2 tons/cII2, and the resulting molded product was sintered at normal pressure at 1850°C for 2 hours in a nitrogen gas atmosphere. By doing so, an aluminum nitride sintered body was obtained. The properties of the obtained aluminum nitride sintered body are also listed in Table 1.
なお、得られた焼結体の表面が若干多孔質となっており
、相対密度及び熱伝導率は均一な組織をもつ部分を切り
出した後得られた焼結体について測募−−」−m=」
友1」LL
本実施例では下記の第2表に記載する組成をもつ混合物
を2トン/c+112の成形圧で成形し、得られた成形
体を窒素ガス雰囲気中1850’Cで2時間常圧焼成す
ることにより窒化アルミニウム焼結体を得た。得られた
窒化アルミニウム焼結体の特性を第2表に併記する。Note that the surface of the obtained sintered body is slightly porous, and the relative density and thermal conductivity were measured for the sintered body obtained after cutting out a part with a uniform structure. In this example, a mixture having the composition shown in Table 2 below was molded at a molding pressure of 2 tons/c+112, and the resulting molded body was heated at 1850'C in a nitrogen gas atmosphere for 2 hours. An aluminum nitride sintered body was obtained by firing under normal pressure. The properties of the obtained aluminum nitride sintered body are also listed in Table 2.
火ILと
本実施例では成形体をつめ粉で覆う焼成方法を使用して
窒化アルミニウム焼結体を得た。成形体及びつめ粉の組
成、及び得られた窒化アルミニウム焼結体の特性を以下
の第3表に記載する。なお、成形体の成形圧は2トン/
Cm2であり、焼成温度は1850℃であり、焼成雰囲
気は窒素ガス雰囲気であった。In this example, an aluminum nitride sintered body was obtained using a firing method in which the compact was covered with nail powder. The compositions of the molded body and nail powder, and the properties of the obtained aluminum nitride sintered body are listed in Table 3 below. In addition, the molding pressure of the molded body is 2 tons/
Cm2, the firing temperature was 1850°C, and the firing atmosphere was a nitrogen gas atmosphere.
[発明の効果コ
本発明方法によれば、窒化アルミニウム粉末に焼結助剤
として酸素を含まず、比較的安定で取り扱い易いシアナ
ミド化合物を用いて酸素含有量の少ない高純度な窒化ア
ルミニウム粉末のみならず、汎用の窒化アルミニウム粉
末を使用しても熱伝導率の高い窒化アルミニウム焼結体
を得ることができる。また、変形もなく且つ均質な窒化
アルミニウム焼結体を製造するための種々の焼成方法を
適宜選択して製造することができる。[Effects of the Invention] According to the method of the present invention, aluminum nitride powder does not contain oxygen as a sintering aid, and a relatively stable and easy-to-handle cyanamide compound is used to produce only high-purity aluminum nitride powder with a low oxygen content. First, even if a general-purpose aluminum nitride powder is used, an aluminum nitride sintered body with high thermal conductivity can be obtained. In addition, various firing methods can be appropriately selected to produce a homogeneous aluminum nitride sintered body without deformation.
Claims (1)
、ストロンチウムシアナミド及び/またはバリウムシア
ナミドまたはカルシウムシアナミドとマグネシウムシア
ナミド、ストロンチウムシアナミド及び/またはバリウ
ムシアナミドを添加・混合し、得られた混合物を成形し
、得られた成形体を窒化アルミニウム粉末にマグネシウ
ムシアナミド、ストロンチウムシアナミド及び/または
バリウムシアナミドまたはカルシウムシアナミドとマグ
ネシウムシアナミド、ストロンチウムシアナミド及び/
またはバリウムシアナミドを添加してなるつめ粉で覆い
焼成するか、または得られた成形体を非酸化性雰囲気中
で焼成するか、またはそれら両者を同時に行なうことを
特徴とする窒化アルミニウム焼結体の製造方法。 2、混合物へのマグネシウムシアナミド、ストロンチウ
ムシアナミド及び/またはバリウムシアナミドまたはカ
ルシウムシアナミドとマグネシウムシアナミド、ストロ
ンチウムシアナミド及び/またはバリウムシアナミドの
添加量が合計で0.01〜7重量%である特許請求の範
囲第1項記載の記載の窒化アルミニウム焼結体の製造方
法。 3、非酸化性雰囲気が窒素であり、窒素圧が常圧以上5
0kg/cm^2以下である特許請求の範囲第1項記載
の窒化アルミニウム焼結体の製造方法。[Claims] 1. Adding and mixing magnesium cyanamide, strontium cyanamide and/or barium cyanamide, or calcium cyanamide and magnesium cyanamide, strontium cyanamide and/or barium cyanamide to aluminum nitride powder, and molding the resulting mixture. The obtained compact is mixed with aluminum nitride powder and magnesium cyanamide, strontium cyanamide and/or barium cyanamide or calcium cyanamide and magnesium cyanamide, strontium cyanamide and/or
Alternatively, an aluminum nitride sintered body is produced by adding barium cyanamide and covering it with nail powder and firing it, or firing the obtained molded body in a non-oxidizing atmosphere, or both at the same time. Production method. 2. Claim 1, wherein the total amount of magnesium cyanamide, strontium cyanamide and/or barium cyanamide, or calcium cyanamide and magnesium cyanamide, strontium cyanamide and/or barium cyanamide added to the mixture is 0.01 to 7% by weight. A method for producing an aluminum nitride sintered body as described in Section 1. 3. The non-oxidizing atmosphere is nitrogen, and the nitrogen pressure is above normal pressure5.
The method for producing an aluminum nitride sintered body according to claim 1, wherein the aluminum nitride sintered body has a weight of 0 kg/cm^2 or less.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP62099995A JPS63265866A (en) | 1987-04-24 | 1987-04-24 | Production of aluminum nitride sintered body |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP62099995A JPS63265866A (en) | 1987-04-24 | 1987-04-24 | Production of aluminum nitride sintered body |
Publications (1)
Publication Number | Publication Date |
---|---|
JPS63265866A true JPS63265866A (en) | 1988-11-02 |
Family
ID=14262212
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP62099995A Pending JPS63265866A (en) | 1987-04-24 | 1987-04-24 | Production of aluminum nitride sintered body |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPS63265866A (en) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2000044345A (en) * | 1998-07-24 | 2000-02-15 | Ngk Insulators Ltd | Aluminum nitride-based sintered compact, corrosion- resistant member, embedded metal product and apparatus for holding semiconductor |
WO2021049618A1 (en) * | 2019-09-12 | 2021-03-18 | 国立大学法人北海道大学 | Sintered body, method for producing same, and dielectric composition |
-
1987
- 1987-04-24 JP JP62099995A patent/JPS63265866A/en active Pending
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2000044345A (en) * | 1998-07-24 | 2000-02-15 | Ngk Insulators Ltd | Aluminum nitride-based sintered compact, corrosion- resistant member, embedded metal product and apparatus for holding semiconductor |
WO2021049618A1 (en) * | 2019-09-12 | 2021-03-18 | 国立大学法人北海道大学 | Sintered body, method for producing same, and dielectric composition |
JPWO2021049618A1 (en) * | 2019-09-12 | 2021-03-18 |
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