JP2007008813A - Aluminum nitride sintered body, its production and semiconductor substrate - Google Patents
Aluminum nitride sintered body, its production and semiconductor substrate Download PDFInfo
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本発明は、半導体基板等に利用される窒化アルミニウム焼結体、特に高い熱伝導性を維持し且つ強度を大幅に向上した窒化アルミニウム焼結体と、その製造方法、及びこの窒化アルミニウム焼結体を用いた半導体基板に関する。 The present invention relates to an aluminum nitride sintered body used for a semiconductor substrate, in particular, an aluminum nitride sintered body maintaining high thermal conductivity and greatly improving strength, a manufacturing method thereof, and the aluminum nitride sintered body The present invention relates to a semiconductor substrate using
窒化アルミニウム焼結体は、高い熱伝導率、電気絶縁性、及びシリコンに近い熱膨張係数を有することから、半導体の放熱基板として使用されてきた。このため、放熱性の向上を目指して窒化アルミニウムの高熱伝導率化の研究が進み、近年では熱伝導率が２００Ｗ／ｍＫを越える焼結体も得られている。 An aluminum nitride sintered body has been used as a heat dissipation substrate for a semiconductor because it has high thermal conductivity, electrical insulation, and a thermal expansion coefficient close to that of silicon. For this reason, research on increasing the thermal conductivity of aluminum nitride has progressed with the aim of improving heat dissipation, and in recent years, sintered bodies having a thermal conductivity exceeding 200 W / mK have been obtained.
しかしながら、このような高熱伝導性の窒化アルミニウム焼結体では、これを構成している焼結粒子の粒径が７〜８μｍ以上と非常に大きくなるために、強度の低下を引き起こすという問題点があった。このため、強度低下を抑える方法が研究され、特開平６−２０６７７２号公報及び特開平６−３２９４７４号公報、特開平７−１７２９２１号公報等に、その方法が提案されている。 However, in such a high thermal conductivity aluminum nitride sintered body, the particle size of the sintered particles constituting it becomes as large as 7 to 8 μm or more, which causes a problem that the strength is lowered. there were. For this reason, methods for suppressing the strength reduction have been studied, and such methods have been proposed in JP-A-6-207772, JP-A-6-329474, JP-A-7-172921, and the like.
例えば、特開平６−２０６７７２号公報には、平均一次粒径が０.０１〜０.３μｍで、不純物酸素量が１.５重量％を越えるＡｌＮ粉末に、７重量％以下の焼結助剤を添加し、非酸化性雰囲気中にて１６００℃以下で焼結する窒化アルミニウム焼結体の製造方法が記載されている。焼結助剤としては、アルカリ土類元素及び／又は希土類元素の化合物や、少量のアルミニウム化合物、シリコン化合物が用いられ、更に必要に応じて遷移金属元素を含む化合物を着色剤として用いることが記載されている。 For example, Japanese Patent Laid-Open No. 6-207772 discloses a sintering aid having an average primary particle size of 0.01 to 0.3 μm and an AlN powder having an impurity oxygen content exceeding 1.5% by weight of 7% by weight or less. Is described, and a method for producing an aluminum nitride sintered body that is sintered at 1600 ° C. or lower in a non-oxidizing atmosphere is described. As the sintering aid, it is described that an alkaline earth element and / or rare earth element compound, a small amount of an aluminum compound, or a silicon compound is used, and if necessary, a compound containing a transition metal element is used as a colorant. Has been.
また、同公報によれば、上記範囲とは異なる平均一次粒径、例えば平均一次粒径が０.５〜１.０μｍのＡｌＮ粉末を併用する方法も提示されている。その実施例によれば、平均粒径１.５μｍ、熱伝導率２２０Ｗ／ｍＫ、４点曲げ強度４５ｋｇ／ｍｍ２（４５９ＭＰａ）の窒化アルミニウム焼結体が得られたことが紹介されている。 Further, according to the publication, a method of using an AlN powder having an average primary particle size different from the above range, for example, an AlN powder having an average primary particle size of 0.5 to 1.0 μm is also presented. According to the example, it is introduced that an aluminum nitride sintered body having an average particle size of 1.5 μm, a thermal conductivity of 220 W / mK, and a four-point bending strength of 45 kg / mm 2 (459 MPa) was obtained.
特開平７−１７２９２１号公報には、含有酸素量が１.５重量％以下で、平均粒径が０.５〜２μｍの微細なＡｌＮ粉末を用い、これに周期律表の３Ａ族、２Ａ族元素の酸化物の少なくとも１種と、少量のＳｉ成分とＡｌ２Ｏ３とを添加し、必要に応じて更に遷移金属元素の酸化物を添加して、非酸化性雰囲気中にて１６５０〜１９００℃で焼結する窒化アルミニウム焼結体の製造方法が開示されている。このＡｌＮ焼結体は、熱伝導率が１５０Ｗ／ｍＫ以上、３点曲げ強度が４９０ＭＰａ以上、破壊靭性値が２.８ＭＮ／ｍ３／２程度と記載されている。 In JP-A-7-172922, fine AlN powder having an oxygen content of 1.5% by weight or less and an average particle size of 0.5 to 2 μm is used, and this includes groups 3A and 2A in the periodic table. At least one elemental oxide, a small amount of Si component, and Al 2 O 3 are added, and an oxide of a transition metal element is further added as necessary, and 1650-1900 in a non-oxidizing atmosphere. A method for producing an aluminum nitride sintered body that is sintered at 0 ° C. is disclosed. This AlN sintered body has a thermal conductivity of 150 W / mK or more, a three-point bending strength of 490 MPa or more, and a fracture toughness value of about 2.8 MN / m 3/2 .
上記したように、高熱伝導率の窒化アルミニウム焼結体の強度低下を抑える方法が提案されているが、いずれの方法においても、窒化アルミニウム原料の酸素量、粉末粒径、焼結助剤、及びその他の添加物等に関する製造条件が多く且つ厳しいため、量産に適した方法とは言えない。 As described above, a method for suppressing the strength reduction of the aluminum nitride sintered body having high thermal conductivity has been proposed. In any method, the oxygen amount of the aluminum nitride raw material, the powder particle size, the sintering aid, and Since the manufacturing conditions for other additives and the like are many and severe, it cannot be said that the method is suitable for mass production.
特に、窒化アルミニウム原料粉末については、その製法やメーカーにより酸素量や粒径が異なるが、上記各公報に記載された方法では原料粉末について特に明記されておらず、しかも通常の固相法で得られた安価な窒化アルミニウム粉末には上記各公報の原料粉末に関する製造条件を満たせるものは少ない。 In particular, for the aluminum nitride raw material powder, the amount of oxygen and the particle size differ depending on the production method and manufacturer, but the method described in each of the above publications does not specify the raw material powder, and it can be obtained by a normal solid phase method. There are few low-cost aluminum nitride powders that can satisfy the manufacturing conditions for the raw material powders described in the publications.
即ち、窒化アルミニウムの場合、同一平均粒径の原料粉末であっても、原料粉末内に存在する格子欠陥によって、得られる焼結体の特性は大きく異なることが知られている。例えば、固相法で得られた通常の粉末は、粉末を合成する際に体積の膨張と収縮が起こるため、粉末粒子内に格子歪等の欠陥が生じやすい。この粉末粒子内の欠陥は焼結体となっても結晶粒子内に残るため、外部応力が加えられたとき破壊起点となり、焼結体の強度低下を引き起こしやすいのである。 That is, in the case of aluminum nitride, it is known that even if the raw material powder has the same average particle diameter, the characteristics of the obtained sintered body are greatly different depending on the lattice defects present in the raw material powder. For example, a normal powder obtained by a solid phase method tends to cause defects such as lattice distortion in the powder particles because volume expansion and contraction occur when the powder is synthesized. Since the defects in the powder particles remain in the crystal particles even when the sintered body is formed, when an external stress is applied, it becomes a starting point for fracture and easily causes a decrease in strength of the sintered body.
本発明は、このような従来の事情に鑑み、通常の安価な粉末を含む殆ど全ての窒化アルミニウム粉末も原料粉末として使用することができ、しかも高熱伝導率であると同時に高強度を有する窒化アルミニウム焼結体、及びその製造方法、並びにこの窒化アルミニウム焼結体を用いた半導体基板を提供することを目的とするものである。 In view of such conventional circumstances, the present invention can use almost all aluminum nitride powder including ordinary inexpensive powder as a raw material powder, and also has high thermal conductivity and at the same time high strength. An object of the present invention is to provide a sintered body, a manufacturing method thereof, and a semiconductor substrate using the aluminum nitride sintered body.
上記目的を達成するため、本発明が提供する窒化アルミニウム焼結体は、平均粒径が２μｍ以下であり、Ｘ線回析により得られる（３０２）面回析線の半価幅が０.２４ｄｅｇ以下であることを特徴とする。 In order to achieve the above object, the aluminum nitride sintered body provided by the present invention has an average particle size of 2 μm or less, and the half width of the (302) plane diffraction line obtained by X-ray diffraction is 0.24 deg. It is characterized by the following.
また、本発明の窒化アルミニウム焼結体の製造方法は、気相化学合成法で得られた平均粒径１.０μｍ以下の窒化アルミニウム粉末１〜９５重量％と、残部が他の窒化アルミニウム粉末からなる原料粉末を調整し、この原料粉末に焼結助剤粉末を添加混合し、得られた混合粉末を成形し、成形体を非酸化性雰囲気中で焼結することを特徴とする。 Moreover, the manufacturing method of the aluminum nitride sintered compact of this invention is 1-95 weight% of aluminum nitride powder with an average particle diameter of 1.0 micrometer or less obtained by the gas phase chemical synthesis method, and the remainder is other aluminum nitride powder. The raw material powder is prepared, a sintering aid powder is added to and mixed with the raw material powder, the obtained mixed powder is molded, and the compact is sintered in a non-oxidizing atmosphere.
上記本発明の窒化アルミニウム焼結体は、その上に金属化層を形成することにより半導体基板とすることができる。金属化層としては、Ｗ、Ｍｏ、Ａｇ、Ｐｄ、Ｐｔ、Ｒｕ、Ｔｉ、Ａｕ、Ｓｎから選ばれた少なくとも１種の元素からなるメタライズ層が好ましく、その上にメッ層を設けることもできる。 The aluminum nitride sintered body of the present invention can be used as a semiconductor substrate by forming a metallized layer thereon. As the metallized layer, a metallized layer made of at least one element selected from W, Mo, Ag, Pd, Pt, Ru, Ti, Au, and Sn is preferable, and a mesh layer can be provided thereon.
本発明によれば、原料粉末中に気相化学合成法で得られた窒化アルミニウム粉末を添加することで、高熱伝導率であると同時に、高い強度を有し、メタライズ層の形成も可能な窒化アルミニウム焼結体を提供することができる。しかも、通気相化学合成法による粉末以外は、通常の安価な殆ど全ての窒化アルミニウム粉末を用いることができ、焼成等の製造条件も細かく制限する必要がないので、その製造上極めて有利である。 According to the present invention, by adding the aluminum nitride powder obtained by the gas phase chemical synthesis method to the raw material powder, nitriding that has high thermal conductivity and at the same time has high strength and can form a metallized layer. An aluminum sintered body can be provided. Moreover, except for powders produced by the gas phase chemical synthesis method, almost all ordinary inexpensive aluminum nitride powders can be used, and it is not necessary to finely limit the production conditions such as firing, which is extremely advantageous in production.
本発明においては、窒化アルミニウム原料粉末のうち、１〜９５重量％を気相化学合成法で得られた窒化アルミニウム粉末とし、残りの部分は気相化学合成法以外で得られた通常の窒化アルミニウム粉末を用いる。気相化学合成法で得られた窒化アルミニウム粉末は、結晶性及び純度に優れている。また、粒径に関しても非常に小さい粉末が得られ、具体的には平均粒径１.０μｍ以下のものを得ることも容易である。 In the present invention, 1 to 95% by weight of the aluminum nitride raw material powder is aluminum nitride powder obtained by a gas phase chemical synthesis method, and the remaining part is ordinary aluminum nitride obtained by a method other than the gas phase chemical synthesis method. Use powder. The aluminum nitride powder obtained by the gas phase chemical synthesis method is excellent in crystallinity and purity. Also, a very small powder can be obtained with respect to the particle size, and it is easy to obtain a powder having an average particle size of 1.0 μm or less.
このような気相化学合成法で得られた窒化アルミニウム粉末を原料粉末の一部とし、通常の他の窒化アルミニウム粉末と混合して用いることにより、量産に適した一般的な製造条件で製造でき、得られる窒化アルミニウム焼結体の高い熱伝導率を維持しながら、高強度化を図ることができる。この高強度化のメカニズムは明らかではないが、およそ以下のごとく考えることができる。 By using the aluminum nitride powder obtained by such a gas phase chemical synthesis method as a part of the raw material powder and mixing it with other ordinary aluminum nitride powder, it can be manufactured under general manufacturing conditions suitable for mass production. The strength can be increased while maintaining the high thermal conductivity of the obtained aluminum nitride sintered body. The mechanism for increasing the strength is not clear, but can be considered as follows.
即ち、気相化学合成法で得られた窒化アルミニウム粉末は、窒素とアルミニウムを気相で直接反応させて得られた粉末であり、粉砕などの処理を行っていないために、結晶性に優れている。しかも、この結晶性の良い窒化アルミニウム粉末は、直接窒化法や還元窒化法等の固相法で得られた通常の窒化アルミニウム粉末と比べて、焼結時に結晶粒成長の核となりやすいため、結晶性に優れた窒化アルミニウム焼結体が得られる。 That is, the aluminum nitride powder obtained by the gas phase chemical synthesis method is a powder obtained by directly reacting nitrogen and aluminum in the gas phase, and since it is not subjected to treatment such as pulverization, it has excellent crystallinity. Yes. In addition, this aluminum nitride powder with good crystallinity is more likely to become the nucleus of crystal grain growth during sintering than ordinary aluminum nitride powder obtained by a solid phase method such as direct nitriding or reduction nitriding. An aluminum nitride sintered body having excellent properties can be obtained.
その結果、焼結体の結晶粒子内の欠陥が少なくなるので、外部応力が焼結体に働いた場合に、粒子内の欠陥から破壊するのではなく、粒子間の粒界から破壊する。このため、粒子内に相対的に多くの欠陥が存在し、この欠陥から破壊する通常の焼結体と比較すると、粒界で破壊する本発明の焼結体の方が優れた強度を備えている。同時にまた、フォノンの散乱も少なくなるため、焼結体の熱伝導率も比較的高いものが得られるものと考えられる。 As a result, since the defects in the crystal grains of the sintered body are reduced, when external stress is applied to the sintered body, the defects are not broken from the defects in the particles but from the grain boundaries between the grains. For this reason, there are relatively many defects in the particles, and the sintered body of the present invention that breaks at the grain boundaries has superior strength compared to a normal sintered body that breaks from the defects. Yes. At the same time, since phonon scattering is reduced, it is considered that a sintered body having a relatively high thermal conductivity can be obtained.
気相化学合成法により得られた粉末の原料粉末中の添加量としては、１〜９５重量％が好適である。その添加量が１重量％未満の場合には、核となる粉末量が少ないために、気相化学合成法により得られた粉末以外の粉末によって粒成長の核となる粒子が形成され、相対的に強度が低下する。また、気相化学合成法で得られた粉末は、粒径が非常に均一であるため成形性に劣るので、その添加量が９５重量％を越えると、成形体の割れや脱脂時の膨れなどが生じやすい。 The addition amount in the raw material powder of the powder obtained by the gas phase chemical synthesis method is preferably 1 to 95% by weight. When the amount added is less than 1% by weight, since the amount of powder serving as a core is small, particles other than the powder obtained by the gas phase chemical synthesis method form particles serving as the core of grain growth. The strength decreases. In addition, the powder obtained by the gas phase chemical synthesis method is inferior in moldability because the particle size is very uniform. If the amount of addition exceeds 95% by weight, the molded body will crack or swell when degreasing. Is likely to occur.
本発明に使用する気相化学合成法により得られた粉末の平均粒径は１.０μｍ以下が好ましい。平均粒径が１.０μｍを越える場合、添加されている気相化学合成法以外の粉末が粒成長の核となる頻度が高くなり、相対的に焼結体の強度の向上のレベルが小さくなるためである。 The average particle size of the powder obtained by the gas phase chemical synthesis method used in the present invention is preferably 1.0 μm or less. When the average particle size exceeds 1.0 μm, the added powder other than the gas phase chemical synthesis method becomes a core of grain growth, and the level of improvement of the strength of the sintered body is relatively reduced. Because.
気相化学合成法で得られた窒化アルミニウム粉末以外の原料粉末については、特に制限はなく、市販の通常の窒化アルミニウム粉末、例えば直接窒化法や還元窒化法等の固相法で得られた粉末を、単一で又は組み合わせて使用することができる。従って、原料粉末の一部として安価な直接窒化法で得られた粉末も使用できるため、焼結体の製造コストを上昇させることなく、高強度の窒化アルミニウム焼結体を得ることが可能である。 The raw material powder other than the aluminum nitride powder obtained by the gas phase chemical synthesis method is not particularly limited, and is a commercially available ordinary aluminum nitride powder, for example, a powder obtained by a solid phase method such as a direct nitriding method or a reducing nitriding method. Can be used singly or in combination. Therefore, since a powder obtained by an inexpensive direct nitriding method can be used as a part of the raw material powder, a high-strength aluminum nitride sintered body can be obtained without increasing the manufacturing cost of the sintered body. .
また、本発明に使用できる焼結助剤に関しても特に制約はなく、一般的な焼結助剤、例えばＹ等の周期律表３Ａ族元素やＣａ等の周期律表２Ａ族元素の酸化物等を、単独で又は複数組み合わせて添加することができる。このため、成形方法に関しても通常行われている手法、即ちプレス法やドクターブレード法等いずれの方法も採用でき、特に制約はない。更に、焼結条件に関しても、使用する焼結助剤に最適の温度で焼結すればよい。 Moreover, there is no restriction | limiting in particular also about the sintering aid which can be used for this invention, For example, the oxide of a periodic table 3A group element, such as Y, etc., periodic table 2A group elements, such as Ca, etc. Can be added singly or in combination. For this reason, it is possible to adopt any method that is usually performed with respect to the molding method, that is, a pressing method or a doctor blade method, and there is no particular limitation. Furthermore, regarding the sintering conditions, the sintering may be performed at the optimum temperature for the sintering aid to be used.
本発明により得られる窒化アルミニウム焼結体は、Ｘ線回析での（３０２）面回折線のピークの半価幅が０.２４ｄｅｇ以下となる。これは、焼結体中に存在する各粒子の結晶が気相化学合成法で得られた粉末を核としているために、結晶性の優れた粒子が結合した焼結体となっているためである。この半価幅が上記の０.２４ｄｅｇを越えた場合、焼結体中に結晶の欠陥が多数存在し、結晶粒径のバラツキも大きいために、得られる焼結体の強度が低下する。 In the aluminum nitride sintered body obtained by the present invention, the half width of the peak of the (302) plane diffraction line in X-ray diffraction is 0.24 deg or less. This is because the crystal of each particle existing in the sintered body is based on the powder obtained by the gas phase chemical synthesis method, so that it becomes a sintered body in which particles having excellent crystallinity are combined. is there. When this half-value width exceeds 0.24 deg as described above, a large number of crystal defects exist in the sintered body and the variation in crystal grain size is large, so that the strength of the obtained sintered body is lowered.
このように、本発明の窒化アルミニウム焼結体は、粒子の結晶性が優れ、結晶の欠陥が少なく、外部応力が焼結体に加えられた場合に粒界で焼結体が破壊するため、高い熱伝導性を維持しながら強度が改善される。即ち、３点曲げ強度で４５０ＭＰａ（４５.９ｋｇ／ｍｍ２）以上のものが得られる。尚、本発明によれば、焼結体の粒径に拘らず強度の改善が得られるが、特に平均粒径が２.０μｍ以下の場合に、より一層高い強度が発現する。このメカニズムは、焼結体の粒径が小さい方が破壊の起点となる粒界にかかる応力を分散でき、相対的に焼結体の強度が高くなるためと考えられる。 Thus, the aluminum nitride sintered body of the present invention has excellent crystallinity of the particles, few crystal defects, and the sintered body breaks at grain boundaries when external stress is applied to the sintered body. Strength is improved while maintaining high thermal conductivity. That is, a three-point bending strength of 450 MPa (45.9 kg / mm 2 ) or more is obtained. According to the present invention, improvement in strength can be obtained regardless of the particle size of the sintered body, but even higher strength is manifested particularly when the average particle size is 2.0 μm or less. This mechanism is considered to be due to the fact that the smaller the particle size of the sintered body can disperse the stress applied to the grain boundary, which is the starting point of fracture, and the strength of the sintered body is relatively increased.
このように、優れた熱伝導性と強度とを兼ね備えた本発明の窒化アルミニウム焼結体は、その表面に通常のごとく金属化層を形成することによって、半導体用の基板とすることができる。例えば、Ｗ、Ｍｏ、Ａｇ、Ｐｄ、Ｐｔ、Ｒｕ等から選択される厚膜メタライズ層を形成したり、Ｔｉ、Ｐｔ、Ａｕ、Ｓｎ等から選択される薄膜メタライズ層を形成することが可能である。更に、金属化層上に、ロウ付け及び耐食性の付与を目的として、ＮｉやＡｕ等のメッキ層を形成することもできる。 Thus, the aluminum nitride sintered body of the present invention having both excellent thermal conductivity and strength can be used as a semiconductor substrate by forming a metallized layer on the surface as usual. For example, it is possible to form a thick metallized layer selected from W, Mo, Ag, Pd, Pt, Ru, etc., or to form a thin metallized layer selected from Ti, Pt, Au, Sn, etc. . Furthermore, a plated layer of Ni or Au can be formed on the metallized layer for the purpose of brazing and imparting corrosion resistance.
一般に、窒化アルミニウム焼結体に厚膜メタライズ層を焼き付けると、メタライズ層と窒化アルミニウムとの熱膨張率差のため、メタライズ基板に反りが生じる。しかし、本発明で得られる窒化アルミニウム焼結体は強度が高いために、通常の焼結体の場合よりも反りの小さなメタライズ基板を得ることができる。また、本発明の窒化アルミニウム焼結体は粒径が小さく、且つ強度に優れているために、薄膜形成する前工程として焼結体を研磨する際に窒化アルミニウム粒子の脱粒が少なく、脱粒しても粒径が小さいため、信頼性の高い薄膜回路パターンを得ることができる。 In general, when a thick metallized layer is baked on an aluminum nitride sintered body, the metallized substrate is warped due to a difference in thermal expansion coefficient between the metallized layer and aluminum nitride. However, since the aluminum nitride sintered body obtained in the present invention has high strength, a metallized substrate having a smaller warp than that of a normal sintered body can be obtained. In addition, since the aluminum nitride sintered body of the present invention has a small particle size and excellent strength, the aluminum nitride particles are less shed when the sintered body is polished as a pre-process for forming a thin film. Since the particle size is small, a highly reliable thin film circuit pattern can be obtained.
［実施例１］
平均粒径０.２μｍの気相化学合成法により得られたＡｌＮ粉末と、直接窒化法により得られた平均粒径２.０μｍのＡｌＮ粉末と、還元窒化法により得られた平均粒径１.０μｍのＡｌＮ粉末をそれぞれ用意した。これらの粉末を表１に示す所定の比率で混合し、得られた各原料粉末１００重量％に対して焼結助剤として２.０重量％のＹｂ２Ｏ３粉末、１.５重量％のＮｄ２Ｏ３粉末及び０.２重量％のＣａＯ粉末を全て加え、更に有機溶剤とバインダーを加えて、ボールミルにより２４時間混合した。得られたスラリーをドクターブレード法によりシートに成形し、所定の大きさに切断した。このときのシート状成形体の状態を、表１に併せて示した。
[Example 1]
An AlN powder obtained by a gas phase chemical synthesis method having an average particle size of 0.2 μm, an AlN powder having an average particle size of 2.0 μm obtained by a direct nitriding method, and an average particle size of 1. 1 obtained by a reduction nitriding method. 0 μm AlN powder was prepared. These powders were mixed at a predetermined ratio shown in Table 1, and 2.0% by weight of Yb 2 O 3 powder, 1.5% by weight as a sintering aid with respect to 100% by weight of the obtained raw material powders. All of Nd 2 O 3 powder and 0.2 wt% CaO powder were added, and an organic solvent and a binder were further added and mixed for 24 hours by a ball mill. The obtained slurry was formed into a sheet by a doctor blade method and cut into a predetermined size. The state of the sheet-like molded body at this time is also shown in Table 1.
上記のごとく作製した各シートを、窒素雰囲気中にて８００℃で脱脂を行い、引き続いて窒素雰囲気中にて１６５０℃で１０時間焼結した。得られた各ＡｌＮ焼結体について、３点曲げ強度、平均粒径、Ｘ線回析による（３０２）面のピークの半価幅、及び熱伝導率を測定し、その結果を表２に示した。 Each sheet produced as described above was degreased at 800 ° C. in a nitrogen atmosphere, and then sintered at 1650 ° C. for 10 hours in a nitrogen atmosphere. About each obtained AlN sintered compact, three point bending strength, an average particle diameter, the half value width of the peak of (302) plane by X-ray diffraction, and thermal conductivity were measured, and the result is shown in Table 2. It was.
表１及び表２から明らかなように、通常のＡｌＮ粉末に気相化学合成法により得られたＡｌＮ粉末を１重量％から９５重量％添加した原料粉末を用いることによって、得られるＡｌＮ焼結体の粒径が微細になり、優れた結晶性が得られると共に、優れた熱伝導率を維持したまま、高い３点曲げ強度を達成することができる。 As is apparent from Tables 1 and 2, an AlN sintered body obtained by using a raw material powder obtained by adding 1 wt% to 95 wt% of an AlN powder obtained by a gas phase chemical synthesis method to an ordinary AlN powder. The particle size becomes fine, and excellent crystallinity is obtained, and a high three-point bending strength can be achieved while maintaining excellent thermal conductivity.
［実施例２］
上記実施例１の試料６と同じＡｌＮ原料粉末の混合比率で、しかし下記表３に示す種々の焼結助剤を用いて、実施例１と同様の工程で焼結してＡｌＮ焼結体を製造した。ただし、各試料の焼結温度は、用いた焼結助剤に適した温度を採用した。得られた各ＡｌＮ焼結体について、実施例１と同様に特性値を測定し、その結果を焼結温度と共に下記表３に示した。
[Example 2]
The same mixing ratio of the AlN raw material powder as that of the sample 6 of Example 1 above, but using various sintering aids shown in Table 3 below, the AlN sintered body was sintered in the same process as in Example 1. Manufactured. However, the temperature suitable for the sintering aid used was adopted as the sintering temperature of each sample. About each obtained AlN sintered compact, the characteristic value was measured similarly to Example 1, and the result was shown in following Table 3 with sintering temperature.
上記表３に示したように、本発明によるＡｌＮ焼結体は、窒化アルミニウムの焼結に通常使用される焼結助剤であれば、どの焼結助剤を用いても、良好な特性を有することが分かる。 As shown in Table 3 above, the AlN sintered body according to the present invention has good characteristics regardless of which sintering aid is used, as long as it is a sintering aid usually used for sintering aluminum nitride. It turns out that it has.
［実施例４］
上記実施例１の試料６と同じ原料粉末及び焼結助剤の混合比率で、しかし気相化学合成法によるＡｌＮ粉末の平均粒径を下記表４のごとく変化させて、実施例１と同様に焼結体を製造した。得られた各ＡｌＮ焼結体について、その特性を実施例１と同様に測定し、その結果を表４に示した。
[Example 4]
The same mixing ratio of the raw material powder and the sintering aid as the sample 6 of Example 1 above, but the average particle diameter of the AlN powder by the gas phase chemical synthesis method was changed as shown in Table 4 below, as in Example 1. A sintered body was produced. About each obtained AlN sintered compact, the characteristic was measured like Example 1, and the result was shown in Table 4.
上記表４の結果から分かるように、原料粉末中に添加する気相化学合成法によるＡｌＮ粉末の平均粒径は１.０μｍ以下が好ましい。 As can be seen from the results in Table 4 above, the average particle diameter of the AlN powder by the gas phase chemical synthesis method added to the raw material powder is preferably 1.0 μm or less.
［比較例］
特開平６−２０６７７２号公報に記載の方法に従って、平均粒径が０.２μｍで不純物酸素量が２.３重量％の還元窒化法により得られたＡｌＮ粉末に、焼結助剤として平均粒径が０.２μｍのＹＦ３粉末を５.０重量％加え、更に有機溶剤とバインダーを添加して、ボールミルにより２４時間混合してスラリーを作製した。次に、このスラリーをドクターブレード法によりシートに形成し、所定の大きさに切断した。このシートを、大気中６００℃で脱脂し、０.８気圧の窒素雰囲気中において１５００℃で１２時間焼結した。
[Comparative example]
According to the method described in Japanese Patent Laid-Open No. 6-207772, an average particle size as a sintering aid is added to an AlN powder obtained by a reductive nitriding method with an average particle size of 0.2 μm and an impurity oxygen content of 2.3 wt%. YF 3 powder having a particle size of 0.2 μm was added by 5.0 wt%, an organic solvent and a binder were further added, and the mixture was mixed for 24 hours by a ball mill to prepare a slurry. Next, this slurry was formed into a sheet by a doctor blade method and cut into a predetermined size. This sheet was degreased at 600 ° C. in the air and sintered at 1500 ° C. for 12 hours in a nitrogen atmosphere of 0.8 atm.
得られた比較例のＡｌＮ焼結体について、実施例１と同様に特性を評価し、その結果を下記表５に示した。尚、参考のために、上記表２に示した本発明の試料５のＡｌＮ焼結体の特性を併記した。この結果から明らかなように、特開平６−２０６７７２号公報記載の方法では、ＡｌＮ焼結体の熱伝導率の改善は大きいものの、３点曲げ強度が極端に低下することが分かる。 About the obtained AlN sintered compact of the comparative example, the characteristic was evaluated similarly to Example 1, and the result was shown in following Table 5. For reference, the characteristics of the AlN sintered body of Sample 5 of the present invention shown in Table 2 above are also shown. As is apparent from this result, the method described in Japanese Patent Laid-Open No. 6-206762 shows that although the improvement in the thermal conductivity of the AlN sintered body is large, the three-point bending strength is extremely lowered.
［実施例４］
上記実施例１の試料６及び試料１１と同一の原料粉末及び組成にてスラリーを作製し、このスラリーからスプレードライヤーにより顆粒状の粉末を作製した。この顆粒状の粉末を、焼結体の寸法が５０×５０×１.０ｍｍサイズになるようにプレス成形し、実施例１と同様の条件で脱脂、及び焼結を行った。
[Example 4]
A slurry was prepared with the same raw material powder and composition as those of Sample 6 and Sample 11 in Example 1, and a granular powder was prepared from the slurry by a spray dryer. This granular powder was press-molded so that the size of the sintered body was 50 × 50 × 1.0 mm, and degreased and sintered under the same conditions as in Example 1.
次に、得られたＡｌＮ焼結体を、厚み０.６３５ｍｍを目標にラップ研磨を行った。この時点での基板の反りは、いずれの試料も１０μｍ以下であった。これらの各ＡｌＮ基板に対して、下記表６に示す種々のメタライズペースト、焼成温度及び焼成雰囲気を用いてメタライズ層を形成し、その密着性、及び全面に塗布した場合の基板の反りについて評価した。 Next, the obtained AlN sintered body was lapped with a thickness of 0.635 mm as a target. The warpage of the substrate at this time was 10 μm or less for all samples. With respect to each of these AlN substrates, metallized layers were formed using various metallized pastes, firing temperatures and firing atmospheres shown in Table 6 below, and their adhesion and warpage of the substrate when applied over the entire surface were evaluated. .
即ち、密着性については、基板上に２ｍｍ角のパターンで各メタライズペーストをスクリーン印刷し、焼成した後、ＷとＭｏのメタライズ層には更にＮｉメッキを厚み２〜４μｍに施した。各試料について、メタライズ層に直径０.６ｍｍのＳｎメッキ銅線を半田により取り付け、そのＳｎメッキ銅線を引っぱることでメタライズ層の密着強度を評価した。また、基板の反りに関しては、基板と同サイズのパターンを全面スクリーン印刷し、焼成後の反り量を測定した。その結果を、原料粉末及び組成が試料６と同一の試料６−ａ、及び同じく試料１１と同一の試料１１−ａに分けて下記表６に示した。 That is, for adhesion, each metallized paste was screen-printed in a 2 mm square pattern on the substrate and baked, and then Ni plating was further applied to the W and Mo metallized layers to a thickness of 2 to 4 μm. For each sample, a 0.6 mm diameter Sn plated copper wire was attached to the metallized layer with solder, and the Sn plated copper wire was pulled to evaluate the adhesion strength of the metallized layer. As for the warpage of the substrate, a pattern having the same size as the substrate was screen-printed, and the amount of warpage after firing was measured. The results are shown in Table 6 below, divided into the raw material powder and the sample 6-a having the same composition as the sample 6, and the same sample 11-a as the sample 11.
以上の結果より、本発明のＡｌＮ焼結体にメタライズ層を形成した基板では、メタライズ層の密着強度を低下させることなく、しかも気相化学合成法によるＡｌＮ粉末を原料としない従来の基板に比べて反り量を大幅に低減させ得ることが分かる。 From the above results, the substrate in which the metallized layer is formed on the AlN sintered body of the present invention does not decrease the adhesion strength of the metallized layer, and compared with a conventional substrate that does not use AlN powder by a gas phase chemical synthesis method as a raw material. It can be seen that the amount of warpage can be greatly reduced.
また、Ｗメタライズ基板とＭｏメタライズ基板の全面メタライズを施したものについて、その上にＮｉメッキを４〜６μｍ施し、更にＡｕメッキを１〜２μｍ施した。これらの外観について４０倍の顕微鏡で観察したところ、両者共にメッキ層の膨れ、染み等もなく、良好なメッキ層が形成されていることが分かった。次に、形成されたＡｕメッキ層上に半田を載せ、水素雰囲気中３５０℃のベルト炉に投入し、半田の流れ具合を観察した。その結果、両者共に半田が十分に流れており、チップ等の実装も可能であることが分かった。 Moreover, about the thing which performed the metallization of the whole surface of W metallization board | substrate and Mo metallization board | substrate, 4-6 micrometers of Ni plating was performed on it, and also Au plating was performed 1-2 micrometers. When these external appearances were observed with a 40-fold microscope, it was found that there was no swelling or staining of the plating layer in both cases, and a good plating layer was formed. Next, solder was placed on the formed Au plating layer, put in a belt furnace at 350 ° C. in a hydrogen atmosphere, and the flow of solder was observed. As a result, it was found that the solder flowed sufficiently in both cases, and it was possible to mount a chip or the like.
［実施例５］
上記実施例４と同様にして、原料粉末及び組成が実施例１の試料６及び試料１１と同一のスラリーを作製し、これをドクターブレード法によりグリーンシートに形成した。このときのシートの厚みは、焼結後の厚みが０.６３５ｍｍになるように調整した。これを６２ｍｍ角に切断し、焼結後の収縮も考えて２.５ｍｍ角のパターンをＷペースト及びＭｏペーストを用いて印刷した。これら各試料を、実施例１と同様の条件で脱脂と焼結を行った。得られたメタライズ基板について実施例４と同様にメタライズ層の密着強度を測定し、その結果を原料粉末及び組成が試料６と同一の試料６−ｂ、及び同じく試料１１と同一の試料１１−ｂに分けて表７に示した。
[Example 5]
In the same manner as in Example 4, slurry having the same raw material powder and composition as those of Sample 6 and Sample 11 of Example 1 was prepared and formed into a green sheet by the doctor blade method. The thickness of the sheet at this time was adjusted so that the thickness after sintering was 0.635 mm. This was cut into 62 mm square, and a 2.5 mm square pattern was printed using W paste and Mo paste in consideration of shrinkage after sintering. These samples were degreased and sintered under the same conditions as in Example 1. For the obtained metallized substrate, the adhesion strength of the metallized layer was measured in the same manner as in Example 4, and the results were obtained as a sample 6-b having the same raw material powder and composition as the sample 6 and the same sample 11-b as the sample 11. The results are shown in Table 7.
また、同様に形成した試料６の別のグリーンシートには、全面にＷペースト又はＭｏペーストを印刷し、実施例１と同様に脱脂と焼結を行った。その後、実施例４と同様にＮｉ及びＡｕメッキを施し、外観並びに半田流れ性を評価した。その結果、両者とも良好な外観、半田流れ性を有していることが分かった。 Moreover, W paste or Mo paste was printed on the entire surface of another green sheet of Sample 6 formed in the same manner, and degreasing and sintering were performed in the same manner as in Example 1. Thereafter, Ni and Au plating was performed in the same manner as in Example 4, and the appearance and solder flowability were evaluated. As a result, it was found that both had good appearance and solder flowability.
以上の結果から、本発明による窒化アルミニウム焼結体は、グリーンシートの焼結と同時にメタライズ層を焼成することもできることが分かる。 From the above results, it can be seen that the aluminum nitride sintered body according to the present invention can also fire the metallized layer simultaneously with the sintering of the green sheet.
［実施例６］
上記実施例４で得られた試料６−ａと試料１１−ａのＡｌＮ焼結体に対して、実施例４と同様に厚みが０.６３５ｍｍになるように鏡面研磨を行った。これらのＡｌＮ基板に、線幅３０μｍ、長さ４０ｍｍ、ピッチ１ｍｍの細線４０本からなる薄膜パターンを、Ｔｉ、Ｐｔ、Ａｕの順番で積層して形成した。
[Example 6]
The AlN sintered bodies of Sample 6-a and Sample 11-a obtained in Example 4 were mirror-polished in the same manner as in Example 4 so that the thickness was 0.635 mm. A thin film pattern composed of 40 fine wires having a line width of 30 μm, a length of 40 mm, and a pitch of 1 mm was laminated on these AlN substrates in the order of Ti, Pt, and Au.
この結果、試料６−ａのＡｌＮ焼結体上に形成した薄膜パターンには断線が認められなかったが、試料１１−ａのＡｌＮ焼結体では導通不良が２本確認された。導通不良のものについてＳＥＭ観察したところ、薄膜パターン上にＡｌＮ粒子の脱粒があり、これが導通不良を引き起こしていることが分かった。 As a result, no disconnection was observed in the thin film pattern formed on the AlN sintered body of Sample 6-a, but two conduction failures were confirmed in the AlN sintered body of Sample 11-a. As a result of SEM observation of those with poor continuity, it was found that there was detachment of AlN particles on the thin film pattern, which caused continuity failure.
［実施例７］
上記実施例４で得られた試料６−ａのＡｌＮ焼結体に対して、実施例６と同様に鏡面研磨を行った。このＡｌＮ基板上の全面に、Ｔｉ、Ｐｔ、Ａｕの順番で薄膜を積層して形成し、その上にＡｕ−Ｓｎ膜を形成した。このＡｕ−Ｓｎ膜の上に、５ｍｍ角のＩＣチップを取り付けたところ、良好な密着性が得られた。
[Example 7]
The AlN sintered body of Sample 6-a obtained in Example 4 was mirror polished in the same manner as in Example 6. A thin film was formed by laminating Ti, Pt, and Au in this order on the entire surface of the AlN substrate, and an Au—Sn film was formed thereon. When a 5 mm square IC chip was mounted on the Au—Sn film, good adhesion was obtained.
Claims (6)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2006268853A JP2007008813A (en) | 1998-05-06 | 2006-09-29 | Aluminum nitride sintered body, its production and semiconductor substrate |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12302298 | 1998-05-06 | ||
| JP2006268853A JP2007008813A (en) | 1998-05-06 | 2006-09-29 | Aluminum nitride sintered body, its production and semiconductor substrate |
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| JP11110351A Division JP2000053470A (en) | 1998-05-06 | 1999-04-19 | Aluminum nitride sintered body, its production and semiconductor substrate |
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| JP2007008813A true JP2007008813A (en) | 2007-01-18 |
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| JP2006268853A Pending JP2007008813A (en) | 1998-05-06 | 2006-09-29 | Aluminum nitride sintered body, its production and semiconductor substrate |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2019021919A1 (en) | 2017-07-24 | 2019-01-31 | 昭和電工株式会社 | Aluminum nitride sintered compact and method for producing same |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2019021919A1 (en) | 2017-07-24 | 2019-01-31 | 昭和電工株式会社 | Aluminum nitride sintered compact and method for producing same |
| KR20200010469A (en) | 2017-07-24 | 2020-01-30 | 쇼와 덴코 가부시키가이샤 | Aluminum nitride sintered body and its manufacturing method |
| US10787392B2 (en) | 2017-07-24 | 2020-09-29 | Showa Denko K.K. | Aluminum nitride sintered compact and method for producing same |
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