JP5566183B2 - Dielectric powder and sintered body and capacitor using the same - Google Patents
Dielectric powder and sintered body and capacitor using the same Download PDFInfo
- Publication number
- JP5566183B2 JP5566183B2 JP2010113359A JP2010113359A JP5566183B2 JP 5566183 B2 JP5566183 B2 JP 5566183B2 JP 2010113359 A JP2010113359 A JP 2010113359A JP 2010113359 A JP2010113359 A JP 2010113359A JP 5566183 B2 JP5566183 B2 JP 5566183B2
- Authority
- JP
- Japan
- Prior art keywords
- powder
- dielectric
- capacitor
- sintered body
- tetragonal
- 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.)
- Expired - Fee Related
Links
Landscapes
- Ceramic Capacitors (AREA)
- Fixed Capacitors And Capacitor Manufacturing Machines (AREA)
- Inorganic Insulating Materials (AREA)
- Compositions Of Oxide Ceramics (AREA)
- Inorganic Compounds Of Heavy Metals (AREA)
Description
本発明は、高誘電率を有する誘電体を製造するための誘電体粉末、特に、微細結晶で正方晶性の高い誘電体粉末と、積層セラミックコンデンサ、コンデンサ内蔵多層基板等に好適に使用できる焼結体及びそれを用いたコンデンサに関する。 The present invention provides a dielectric powder for producing a dielectric having a high dielectric constant, in particular, a dielectric powder having fine crystallinity and high tetragonality, a sintered ceramic capacitor, a multilayer board with a built-in capacitor, and the like. The present invention relates to a bonded body and a capacitor using the same.
従来から、大容量のセラミックコンデンサとして誘電体磁器組成物からなるセラミック層間に内部電極を配置した構造の積層セラミックコンデンサが広く知られており、前記積層セラミックコンデンサとして好適な誘電体磁器組成物が数多く開発されている。 Conventionally, a multilayer ceramic capacitor having a structure in which internal electrodes are arranged between ceramic layers made of a dielectric ceramic composition has been widely known as a large-capacity ceramic capacitor, and there are many dielectric ceramic compositions suitable as the multilayer ceramic capacitor. Has been developed.
これらのセラミックコンデンサ用誘電体磁器組成物として、ＢａＴｉＯ３を主成分とするチタン酸バリウム系及びチタン酸ストロンチウム系の誘電体磁器組成物をベースにしたペロブスカイト型複合酸化物を例示できる。 Examples of these dielectric ceramic compositions for ceramic capacitors include perovskite complex oxides based on barium titanate-based and strontium titanate-based dielectric ceramic compositions mainly composed of BaTiO 3 .
また、パーソナルコンピュータ、携帯電話などの情報通信技術の発展と共に電子部品の小型化が急速に進み、積層セラミックコンデンサの小型化の要求がさらに強まり、誘電体セラミック材料の大容量化、すなわち誘電率の向上と積層セラミックコンデンサにおいては更なる薄層化の必要性が生じてきている。 In addition, with the development of information and communication technologies such as personal computers and mobile phones, the miniaturization of electronic components has rapidly progressed, and the demand for miniaturization of multilayer ceramic capacitors has further increased. There is a need for further thinning in the improvement and multilayer ceramic capacitors.
そして、薄層化のためにはコンデンサを構成する焼結体の結晶粒子径の微細化が要求され、それに伴い、原料粉末の微細化が不可欠となっている。しかも、コンデンサの誘電率を高めるために、原料粉末の結晶構造は正方晶であることが強く望まれている。 In order to reduce the thickness, it is required to reduce the crystal particle diameter of the sintered body constituting the capacitor, and accordingly, it is indispensable to reduce the raw material powder. Moreover, in order to increase the dielectric constant of the capacitor, it is strongly desired that the crystal structure of the raw material powder is a tetragonal crystal.
一方、マイクロ波加熱は、一般の電気炉に比べて処理温度を低減することができ、また処理時間を短縮できるという特徴を有しており、この方法を用いたセラミック粉末の合成も試みられている。 On the other hand, microwave heating has the characteristics that the processing temperature can be reduced and the processing time can be shortened as compared with a general electric furnace, and synthesis of ceramic powder using this method has been attempted. Yes.
例えば、下記の非特許文献１では、塩化バリウム・二水和物と酸化チタンからの水熱合成の際に２．４５ＧＨｚのマイクロ波を用い、ＢａＴｉＯ３が合成されている。 For example, in the following Non-Patent Document 1, BaTiO 3 is synthesized using 2.45 GHz microwaves during hydrothermal synthesis from barium chloride dihydrate and titanium oxide.
また、下記の特許文献１では、粉砕処理することなく粒子形状が揃った微細かつ高純度のセラミック粉末が低温短時間のマイクロ波を用いた仮焼により合成可能であることが開示されている。 Patent Document 1 below discloses that a fine and high-purity ceramic powder having a uniform particle shape can be synthesized by calcination using a microwave at a low temperature for a short time without being pulverized.
しかしながら、上記非特許文献１に記載の方法によれば、水熱合成後のＢａＴｉＯ３粉末は立方晶を呈しており、正方晶を得るためには更に８５０℃で熱処理が必要となり、それでもなお正方晶の量が立方晶に比べて少なく、これを用いて焼成すると焼結体の誘電率が低いという問題があった。 However, according to the method described in Non-Patent Document 1, the BaTiO 3 powder after hydrothermal synthesis has a cubic crystal, and further heat treatment is required at 850 ° C. in order to obtain a tetragonal crystal. There is a problem that the amount of crystals is smaller than that of cubic crystals, and the sintered body has a low dielectric constant when fired.
また、特許文献１では低温短時間で複合ペロブスカイト相、スピネル相、ガーネット相が合成可能であるものの、合成されたペロブスカイト相は菱面体晶であり、これを用いて焼成すると焼結体の誘電率が低いという問題があった。 In Patent Document 1, a composite perovskite phase, spinel phase, and garnet phase can be synthesized at a low temperature in a short time, but the synthesized perovskite phase is a rhombohedral crystal. There was a problem of low.
従って、本発明は、微細結晶粒からなり、かつ正方晶性が高い誘電体粉末及び積層化に適した高誘電率の焼結体並びにそれを用いたコンデンサを提供することを目的とする。 Accordingly, an object of the present invention is to provide a dielectric powder composed of fine crystal grains and having high tetragonality, a sintered body having a high dielectric constant suitable for lamination, and a capacitor using the same.
本発明は、チタニア粉末と、周期律表第２ａ族元素を含む炭酸塩粉末又は酸化物粉末との混合粉末に５ＧＨｚ以上の周波数のマイクロ波を照射し加熱することにより、正方晶ペロブスカイト結晶構造が得られ、しかも得られる粉末は微細な結晶から構成され、さらにこの粉末を用いて焼成することにより、１μｍ以下の結晶粒子径からなり、高誘電率を有する焼結体が得られるという知見に基づくものである。 In the present invention, a tetragonal perovskite crystal structure is obtained by irradiating a mixed powder of a titania powder and a carbonate powder or an oxide powder containing a group 2a element of the periodic table by irradiating with a microwave having a frequency of 5 GHz or more. Based on the knowledge that the obtained powder is composed of fine crystals, and further sintered by using this powder, a sintered body having a crystal particle diameter of 1 μm or less and having a high dielectric constant can be obtained. Is.
即ち、本発明の誘電体粉末は、チタン酸ストロンチウムを主成分として含み、平均結晶粒子径が０．５〜０．９μｍであるとともに、Ｘ線回折によるｃ軸の格子定数とａ軸の格子定数の比ｃ／ａが１．００９１２〜１．００９６２であることを特徴とするものである。
That is, dielectric powder of the present invention comprises a titanium strontium as a main component, with an average crystal grain size of 0.5 to 0.9 [mu] m, the a-axis and c-axis lattice constant by X-ray diffraction The ratio of lattice constants c / a is 1.009 12 to 1.00962 .
また、本発明の焼結体は、上記の誘電体粉末の成形体を焼成して得られ、誘電率が２０００以上であることを特徴とするもので、これによりコンデンサの誘電体厚みが１μｍ以下とすることができ薄層化に寄与することができる。また正方晶性が高いため微細結晶粒であるにも関わらず高い誘電率を有しており、コンデンサの小型化又は大容量化を図ることが可能となる。
Further, the sintered body of the present invention is obtained by firing the above-mentioned dielectric powder compact, and has a dielectric constant of 2000 or more, whereby the dielectric thickness of the capacitor is 1 μm or less. And can contribute to thinning. In addition, since the tetragonal nature is high, it has a high dielectric constant despite being fine crystal grains, and it is possible to reduce the size or increase the capacity of the capacitor.
また、本発明のコンデンサは、前記焼結体と、内部電極とを交互に積層して設けられてなることを特徴とする。これによって、誘電体層中の誘電体粒子が１μｍ以下であるために誘電体厚みを１μｍ以下にすることができ、また誘電体粒子の正方晶性が高いため誘電率も高く、高い静電容量を得ることができ、少ない積層数で同じ容量が得られるため小型化でき、また、同一の容積でも大容量化することが可能となる。 The capacitor of the present invention is characterized in that the sintered body and internal electrodes are alternately laminated. Thereby, since the dielectric particles in the dielectric layer are 1 μm or less, the dielectric thickness can be 1 μm or less, and since the tetragonal nature of the dielectric particles is high, the dielectric constant is also high and the capacitance is high. Since the same capacity can be obtained with a small number of layers, the size can be reduced, and the capacity can be increased even with the same volume.
本発明によれば、平均結晶粒子径が０．５〜１μｍで、Ｘ線回折によるｃ軸の格子定数とａ軸の格子定数の比ｃ／ａが１．００９以上である誘電体粉末の成形体を焼成することにより、１μｍ以下の平均結晶粒子径を有し、高誘電率を有する焼結体を実現できる。
According to the present invention, the average crystal grain size of 0.5 to 1 [mu] m, the ratio c / a of the lattice constant of the a axis of the c-axis by X-ray diffraction of the dielectric powder is 1.009 or more by the this firing the shaped body has an average crystal grain size of 1μm or less, it can be realized a sintered body having a high dielectric constant.
本発明の誘電体粉体は、チタン酸ストロンチウムを含有し、結晶構造がペロブスカイトからなり、平均結晶粒子径が０．５〜０．９μｍであることが重要であり、誘電体粉末の平均結晶粒子径が０．９μｍを越えると、焼結体の平均結晶粒子径が０．９μｍを越えてしまい、特にコンデンサ等の薄層で用いる場合に適さないものとなる。
The dielectric powder of the present invention contains titanium strontium, the crystal structure becomes a perovskite, it is important that the average crystal grain size of 0.5 to 0.9 [mu] m, the average of the dielectric powder When the crystal particle diameter exceeds 0.9 μm, the average crystal particle diameter of the sintered body exceeds 0.9 μm, which is not particularly suitable for use in a thin layer such as a capacitor.
この誘電体粉末は、凝集している粉末を意味するものではなく、凝集体を形成する個々の結晶からなる一次粒子を指すものであり、その平均結晶粒子径の測定は、合成後十分解砕し、ＳＥＭにより凝集粒がないのを確認した後、再度超音波ホモジナイザーにより分散し、粒度分布を測定し、測定結果のｄ５０を平均結晶粒子径とする。
The dielectric powder is not intended to mean the end flour are aggregated, is intended to refer to primary particles composed of individual crystals which form aggregates, the measurement of the average crystal grain size is synthesized after ten decomposition After crushing and confirming the absence of aggregated particles by SEM, the particles are dispersed again by an ultrasonic homogenizer, the particle size distribution is measured, and d50 of the measurement result is taken as the average crystal particle size.
また、Ｘ線回折によるc軸の格子定数とa軸の格子定数の比ｃ／ａが１．００９以上であることが重要であり、特に１．００９５以上、さらには１．００９８以上であることが好ましい。これにより、粉末の正方晶性が高いため、焼成したときに高誘電率が得られ、コンデンサの薄層化、高容量化を実現できる。 In addition, it is important that the ratio c / a of the c-axis lattice constant to the a-axis lattice constant by X-ray diffraction is 1.009 or more, particularly 1.0095 or more, and further 1.0098 or more. Is preferred. Thereby, since the tetragonal nature of the powder is high, a high dielectric constant can be obtained when fired, and the capacitor can be made thinner and have a higher capacity.
つまり、このc軸の格子定数とa軸の格子定数の比ｃ／ａは、正方晶性の指標となっており、ｃとａとが同一である立方晶が少なくなり、ｃがａより大きい正方晶が大きくなると、ｃ／ａが大きくなって正方晶性の高い粉末となる。従って、粉末のｃ／ａを１．００９以上にすることによって、この粉末を用いて作製した焼結体の正方晶の割合を高くでき、その結果、高い誘電率を得ることができる。 That is, the ratio c / a between the lattice constant of the c axis and the lattice constant of the a axis is a tetragonal index, and there are fewer cubic crystals in which c and a are the same, and c is larger than a. When the tetragonal crystal becomes large, c / a becomes large and the powder becomes highly tetragonal. Therefore, by setting the c / a of the powder to be 1.009 or more, the ratio of tetragonal crystals in a sintered body produced using this powder can be increased, and as a result, a high dielectric constant can be obtained.
このｃ／ａが１．００９より小さいと、正方晶の割合が小さく、得られる焼結体中の正方晶の割合も小さく、その結果、誘電率も小さくなってしまい、特にコンデンサには不適な組成となる。 If this c / a is less than 1.009, the proportion of tetragonal crystals is small, and the proportion of tetragonal crystals in the resulting sintered body is also small, resulting in a small dielectric constant, which is not suitable for a capacitor. It becomes a composition.
上記のように、平均結晶粒子径が０．５〜１μｍの誘電体粉末において、正方晶性を高
めることによって、特にコンデンサに最適の組成物として、大容量化、薄層化及び小型化に大きな寄与が可能となる。
As described above, in the dielectric powder having an average crystal particle size of 0.5 to 1 μm, by increasing the tetragonal property, it is particularly suitable as a composition for a capacitor. A big contribution is possible.
次に、本発明の誘電体粉末の製造方法について説明する。 Next, the manufacturing method of the dielectric powder of this invention is demonstrated.
まず、チタニア粉末と、ＳｒＣＯ３との混合粉末を準備する。これらの平均粒子径が１μｍ以下であることが、反応性を高める点で好ましい。そして、平均粒子径が０．８μｍ以下の原料粉末を用いることにより、合成後の誘電体粉末の平均結晶粒子径を０．５〜０．９μｍにすることが容易となる。
First, a titania powder, a mixed powder of S RCO 3. These average particle diameters are preferably 1 μm or less from the viewpoint of increasing the reactivity. Then, by using a raw material powder having an average particle diameter of 0.8 μm or less, it becomes easy to make the average crystal particle diameter of the synthesized dielectric powder 0.5 to 0.9 μm.
チタニア粉末は、ルチル構造、アナターゼ構造のどちらでも構わないが、平均粒子径は、反応性を考慮すると極力微細であることが望ましく、１μｍ以下、特に０．７μｍ以下、さらには０．５μｍ以下、より好適には０．３μｍ以下が好ましい。
Titania powder is rutile structure, but may be either anatase structure, flat Hitoshitsubu Ko径is desirably minimized fine considering the reactivity, 1 [mu] m or less, especially 0.7μm or less, more 0.5μm Hereinafter, 0.3 μm or less is more preferable.
また、ＳｒＣＯ３の粒径も微細であることが望ましく、０．８μｍ以下がよい。
Further, it is desirable particle size of the S RCO 3 is also fine, have good is 0.8 [mu] m or less under.
なお、これらの微細な原料粉末の製造方法としては、ゾル・ゲル法、水熱合成法、気相化学反応法(ＣＶＤ法)等を挙げることができる。 Examples of a method for producing these fine raw material powders include a sol-gel method, a hydrothermal synthesis method, and a gas phase chemical reaction method (CVD method).
上記の粉末をチタニア粉末とその他の粉末とのモル比で同量程度になるように調合することにより、未反応物の発生の極めて少ない良質の誘電体粉末を作製することができる。例えば、ＴｉＯ２のモル比とＢａＣＯ３のモル比を１：１と同程度にするように調合する。 By blending the above powder so that the molar ratio of titania powder and other powders is about the same amount, a high-quality dielectric powder with very little generation of unreacted substances can be produced. For example, the molar ratio of TiO 2 and the molar ratio of BaCO 3 are adjusted to about the same as 1: 1.
なお、ＢａＴｉＯ３粉末を作製する場合、ＢａおよびＴｉサイトの一部を他の元素で置き換えるために、他の元素を炭酸塩粉末又は酸化物粉末として加えておき、マイクロ波加熱による反応時に固溶させることも可能である。また、他の反応系においても同様の置換
が可能である。
When preparing BaTiO 3 powder, in order to replace part of the Ba and Ti sites with other elements, other elements are added as carbonate powder or oxide powder, and are dissolved during the reaction by microwave heating. It is also possible to make it. The same substitution is possible in other reaction systems.
この混合粉末をボールミル等の公知の方法で混合及び／又は粉砕し、成形する。
例えば、アクリル系、ブチラール系、アルコール系等の有機結合剤、溶媒等を添加し、ボールミル、振動ミル等により混合する。得られた混合粉末又はスラリーを公知の成型方法により所望の形状に成形する。具体例として、一軸プレス法、ドクターブレード法を例示できる。
The mixed powder is mixed and / or pulverized by a known method such as a ball mill and then molded.
For example, an organic binder such as acrylic, butyral, or alcohol, a solvent, or the like is added and mixed by a ball mill, a vibration mill, or the like. The obtained mixed powder or slurry is molded into a desired shape by a known molding method. Specific examples include a uniaxial press method and a doctor blade method.
次に、成形体をマイクロ波加熱装置の共振器内に配置し、５ＧＨｚ以上のマイクロ波を照射し、加熱することにより合成することが重要である。このマイクロ波は、マグネトロン、クライストロン又はジャイロトロン等の発振管より発振され、導波管を通して空洞共振器内に導かれ、成形体に照射される。 Next, it is important to synthesize the molded body by placing it in a resonator of a microwave heating apparatus, irradiating with a microwave of 5 GHz or more and heating. This microwave is oscillated from an oscillating tube such as a magnetron, a klystron, or a gyrotron, is guided into the cavity resonator through the waveguide, and is irradiated onto the molded body.
５ＧＨｚ以上のマイクロ波を用いるのは、５ＧＨｚ以上のマイクロ波加熱により、低温短時間合成、また微細結晶粒でも高い正方晶性を有する粉末が合成可能であるためであるが、そのメカニズムについて詳細は明らかでないが、マイクロ波照射により、熱的な物質の移動に加え、粒子表面の拡散が促進され、チタニア粒子とＢａやＳｒ等の周期律表第２ａ族元素を含む炭酸塩粉末粒子又は酸化物粉末粒子の接触面での反応を促進すると考えられ、特に、２８ＧＨｚ以上が好ましい。 The reason why microwaves of 5 GHz or higher are used is that it is possible to synthesize powders having high tetragonal properties even with fine crystal grains at low temperature and short time by microwave heating of 5 GHz or more. Although it is not clear, the microwave irradiation promotes the diffusion of the particle surface in addition to the thermal movement of the material, and the carbonate powder particles or oxides containing titania particles and Group 2a elements of the periodic table such as Ba and Sr It is considered that the reaction at the contact surface of the powder particles is promoted, and in particular, 28 GHz or more is preferable.
また、チタニア粉末の平均粒子径をｄA、周期律表第２ａ族元素を含む炭酸塩粉末又は
酸化物粉末の平均粒子径をｄＢとすると、ｄＢ／ｄＡが１．５以上であることが好ましい。つまり、本発明の粉末を作製する反応系においては、チタンの拡散が律速となり、しかもその反応が固相反応であるため、チタンの粒径を特に小さくして反応性を高めることが正方晶性を高めるために好ましいのである。即ち、チタニアの粒径が細かく比表面積が大きくなり、粒子表面に作用されると考えられるマイクロ波が効果的に働き、マイクロ波の単純な熱的効果ではなく、非熱的効果と呼ばれる効果が発現する。この効果によって拡散が促進されて低温かつ短時間合成が可能となり、またマイクロ波の結晶格子への作用により微細結晶粒でありながら正方晶性の高い粉末を得ることができる。
Further, when the average particle diameter of titania powder is dA and the average particle diameter of carbonate powder or oxide powder containing Group 2a element of the periodic table is dB, dB / dA is preferably 1.5 or more. In other words, in the reaction system for producing the powder of the present invention, the diffusion of titanium is rate-limiting, and the reaction is a solid-phase reaction. It is preferable in order to increase. That is, the particle size of titania is small, the specific surface area is large, and the microwave that is considered to act on the particle surface works effectively, and there is an effect called a non-thermal effect rather than a simple thermal effect of the microwave. To express. Due to this effect, diffusion is promoted to enable synthesis at a low temperature and for a short time, and the action of microwaves on the crystal lattice makes it possible to obtain a powder having high tetragonal properties despite being fine crystal grains.
ｄＢ／ｄＡが１．５未満であるとマイクロ波の非熱的効果が顕著にならず、低温短時間合成は可能であるものの正方晶性の高い微細結晶粒を得ることができなくなる。 When dB / dA is less than 1.5, the non-thermal effect of the microwave is not remarkable, and although low-temperature and short-time synthesis is possible, fine crystal grains with high tetragonality cannot be obtained.
なお、成形体はアルミナ繊維等からなる断熱材にて周囲を囲むことで試料表面からの放熱を抑制でき、効果的に加熱することができる。 In addition, the molded body can suppress heat dissipation from the sample surface by surrounding the periphery with a heat insulating material made of alumina fiber or the like, and can be heated effectively.
また、試料温度は公知の測定方法、例えばタングステン−レニウム等の熱電対や二色温度計等の非接触法で測定することができる。 The sample temperature can be measured by a known measurement method, for example, a non-contact method such as a thermocouple such as tungsten-rhenium or a two-color thermometer.
上記成形体は５００〜１０００℃、特に７００〜９００℃の温度範囲において、３０分以下、特に２０分以下の合成時間で製造することが好ましい。これによって、低温で合成反応を短時間で完了することができ、その結果、粉末の結晶粒子の粒成長がほとんど起こることなく、また、原料粉末が残留することなく正方晶性の高いＢａＴｉＯ３を合成することが可能となる。 The molded article is preferably produced in a temperature range of 500 to 1000 ° C., particularly 700 to 900 ° C., with a synthesis time of 30 minutes or less, particularly 20 minutes or less. As a result, the synthesis reaction can be completed in a short time at a low temperature. As a result, almost no growth of crystal grains of the powder occurs, and BaTiO 3 having a high tetragonal property is obtained without the raw material powder remaining. It is possible to synthesize.
また、上記の熱処理の雰囲気は、大気中で可能であるが、所望によりＡｒ、Ｎ２等をキャリアガスとし、所望により酸素含有ガスを用いて、酸素分圧を制御した雰囲気で行うことが好ましい。これにより、成形体は、チタン酸ストロンチウムを主成分として含み、平均結晶粒子径が０．５〜０．９μｍ、Ｘ線回折によるc軸の格子定数とa軸の格子定数の比から算出される結晶軸の長さの比ｃ／ａが１．００９１２〜１．００９６２であるものにすることができる。そして、この成形体を粉砕することにより、誘電体粉末を得ることができる。
The atmosphere for the heat treatment described above can be performed in the atmosphere, but it is preferable to perform in an atmosphere in which the partial pressure of oxygen is controlled by using Ar, N 2 or the like as a carrier gas, and optionally using an oxygen-containing gas. . This calculation, moldings comprises titanium strontium as a main component, the mean crystal grain size of 0.5 to 0.9 [mu] m, from the ratio of the lattice constant of a-axis and c-axis lattice constant by X-ray diffraction The ratio c / a of the lengths of the crystal axes can be 1.009 12 to 1.00962 . And dielectric powder can be obtained by grind | pulverizing this molded object.
このようにして得られた本発明の誘電体粉末は、平均結晶粒子径が０．５〜１μｍと微細でありながら高い正方晶性を示すため、特にコンデンサ等の薄層を形成するために最適である。
The dielectric powder of the present invention thus obtained has an average crystal particle size of 0.5 to 1 μm and exhibits a high tetragonal property while being fine, so that a thin layer such as a capacitor is particularly formed. Is optimal.
また、本発明の焼結体は、本発明の誘電体粉末の成形体を用いて作製されたものである。
Further, the sintered body of the present invention which is manufactured using the molded product of the dielectric powder of the present invention.
また、Ｘ線回折によるｃ軸の格子定数とａ軸の格子定数の比ｃ／ａが１．００９以上あることが重要であり、特に１．００９５以上、さらには１．００９８以上であることが好ましい。これにより、微細結晶粒でありながら正方晶性が高く誘電率の高い誘電体となる。 In addition, it is important that the ratio c / a of the c-axis lattice constant to the a-axis lattice constant by X-ray diffraction is 1.009 or more, particularly 1.0095 or more, further 1.0098 or more. preferable. Thereby, although it is a fine crystal grain, it becomes a dielectric material with high tetragonality and a high dielectric constant.
さらに、誘電率が２０００以上であることが重要であり、特に３０００以上、さらには４０００以上であることが好ましい。これにより、コンデンサの薄層化、小型化、大容量化に寄与することができる。 Further, it is important that the dielectric constant is 2000 or more, particularly 3000 or more, further 4000 or more is preferable. As a result, the capacitor can be made thinner, smaller, and larger in capacity.
これらの誘電体粉末には、焼結助剤等としてＹ２Ｏ３等の希土類元素やＭｇＯ、ＭｎＯ等を誘電特性に影響の少ない範囲で添加してもよい。
The dielectric powder of these rare earth elements and MgO, such as Y 2 O 3 as a sintering aid, etc., may be added in a small range of influence of MnO or the like on the dielectric properties.
また、本発明のコンデンサは、上記の焼結体と、内部電極とが、交互に積層されてなることを特徴とするもので、これにより、焼結体を１μｍ程度又はそれ以下に薄層化でき、また、同一の容積でも積層数が多いため大容量化することが可能となる。 The capacitor of the present invention is characterized in that the above sintered body and internal electrodes are alternately laminated, whereby the sintered body is thinned to about 1 μm or less. In addition, since the number of stacked layers is large even in the same volume, the capacity can be increased.
出発原料には、ルチル構造及びアナターゼ構造のＴｉＯ２粉末に対して、第２原料としてＢａＣＯ３粉末、ＳｒＣＯ３粉末を表１の組成で秤量した。そして、この混合粉末１００ｇに対して、分散媒としてＩＰＡ(イソプロピルアルコール)を１５０ｃｃ、ＺｒＯ２ボールを１５００ｇ加え、ボールミルにて２０時間混合した。 As starting materials, BaCO 3 powder and SrCO 3 powder were weighed as compositions of Table 1 with respect to TiO 2 powder having a rutile structure and an anatase structure. To 100 g of this mixed powder, 150 cc of IPA (isopropyl alcohol) and 1500 g of ZrO 2 balls were added as a dispersion medium, and mixed for 20 hours in a ball mill.
得られた混合粉末は、乾燥及び造粒後、金型に充填し、一軸プレス法にて１００ＭＰａの成形圧で、直径２０ｍｍ、厚さ２ｍｍの成形体を作製した。 The obtained mixed powder was dried and granulated, and then filled into a mold, and a molded body having a diameter of 20 mm and a thickness of 2 mm was produced at a molding pressure of 100 MPa by a uniaxial pressing method.
次に、マイクロ波加熱炉及び抵抗加熱焼成炉により上記の成形体を加熱した。
即ち、マイクロ波加熱炉のマイクロ波源として、２．４５ＧＨｚ、出力２ｋＷのマグネトロン、周波数６ＧＨｚ、出力８ｋＷのクライストロン、周波数２８ＧＨｚ、出力１０ｋＷのジャイロトロンのいずれかを、空洞共振器内のアルミナ断熱材中に設置さらた成形体に照射し、加熱処理を行った。加熱は２０℃/分の速度で昇温し、表１に示す条件で熱処理
した。なお、雰囲気は大気中とした。
Next, the molded body was heated by a microwave heating furnace and a resistance heating firing furnace.
That is, as a microwave source for a microwave heating furnace, either a 2.45 GHz magnetron with an output of 2 kW, a klystron with a frequency of 6 GHz, an output of 8 kW, a gyrotron with a frequency of 28 GHz, or an output of 10 kW is used in the alumina heat insulating material in the cavity resonator. The molded body that had been placed on the surface was irradiated and heat-treated. Heating was performed at a rate of 20 ° C./min, and heat treatment was performed under the conditions shown in Table 1. The atmosphere was air.
得られた合成体を振動ミルにて粉砕し、Ｘ線回折により構成相の同定を行った。またこれらのＸ線回折の(２００)ピークと(００２)ピークから算出される面間隔ｄ（２００）とｄ（００２）の関係（ｄ（００２）／ｄ（２００））１／２から正方晶性を示す結晶軸長比ｃ／ａを算出した。なお、立方晶のみの場合には、ｃ／ａを１とした。 The obtained composite was pulverized with a vibration mill, and the constituent phases were identified by X-ray diffraction. Further, the relationship between the interplanar spacing d (200) and d (002) calculated from the (200) peak and the (002) peak of these X-ray diffractions (d (002) / d (200)) 1/2 is a tetragonal crystal. The crystal axis length ratio c / a showing the property was calculated. In the case of only cubic crystals, c / a was set to 1.
誘電体粉末の平均結晶粒子径は、合成後に十分解砕し、ＳＥＭにより凝集粒がないのを確認した後、再度超音波ホモジナイザーにより分散し、粒度分布を測定した。そして測定結果のｄ５０を平均結晶粒子径とした。
The average crystal grain size of the dielectric powder was ten decomposed granulated after synthesis, after confirming that the absence of agglomerated grain by SEM, was dispersed by an ultrasonic homogenizer again, particle size distribution was measured. And d50 of the measurement result was made into the average crystal particle diameter.
また、粉砕して得られた誘電体粉末１００ｇに対して、分散媒としてＩＰＡを１５０ｃｃ加え、１５００ｇのＺｒＯ２ボールを有するボールミルにて２０時間混合した。
Further, 150 cc of IPA was added as a dispersion medium to 100 g of the dielectric powder obtained by pulverization, and mixed for 20 hours in a ball mill having 1500 g of ZrO 2 balls.
得られた混合粉末は、乾燥及び造粒後、金型に充填し、一軸プレス法にて１００ＭＰａの成形圧で、直径２０ｍｍ、厚さ２ｍｍの成形体を作製した。 The obtained mixed powder was dried and granulated, and then filled into a mold, and a molded body having a diameter of 20 mm and a thickness of 2 mm was produced at a molding pressure of 100 MPa by a uniaxial pressing method.
そして、この成形体を１２５０℃×２ｈの還元性雰囲気で焼成し、焼結体を作製し、焼結体の破面のＳＥＭによる断面写真を用いてインターセプト法により平均結晶粒子径を求めた。また、ブリッジ法により室温で１ＫＨｚ時の誘電率を測定した。
結果を表１に示す。
And this molded object was baked in 1250 degreeC * 2h reducing atmosphere, the sintered compact was produced, and the average crystal particle diameter was calculated | required by the intercept method using the cross-sectional photograph by SEM of the fracture surface of a sintered compact. Moreover, the dielectric constant at 1 KHz was measured at room temperature by the bridge method.
The results are shown in Table 1.
試料Ｎｏ．１〜７、９〜１８及び２５〜２８は、平均結晶粒子径が０．５〜１μｍ、格子定数の比ｃ／ａが１．００９１２以上であり、この粉末を用いて作製した焼結体は誘電率が２０００以上であった。 Specimen No. 1 to 7, 9 to 18 and 25 to 28 have an average crystal particle size of 0.5 to 1 μm and a lattice constant ratio c / a of 1.00912 or more. The dielectric constant was 2000 or more.
一方、マイクロ波周波数が２．４５ＧＨｚと小さく、本発明の範囲外の試料Ｎｏ．８は、粒子径が０．９μｍであったものの、格子定数の比ｃ／ａが１．００８１２と小さく、この粉末を用いて作製した焼結体は誘電率が１２００と小さいものであった。 On the other hand, the microwave frequency is as small as 2.45 GHz, and sample No. No. 8 had a particle diameter of 0.9 μm, but the lattice constant ratio c / a was as small as 1.00812, and the sintered body produced using this powder had a dielectric constant as small as 1200.
また、マイクロ波加熱を用いず、電気炉による熱処理を行った本発明の範囲外の試料Ｎｏ．１９〜２４のうち、試料Ｎｏ．１９〜２３は格子定数の比ｃ／ａが１．００７２１以
下と小さく、この粉末を用いて作製した焼結体は誘電率が１６００以下と小さいものであった。また、試料Ｎｏ．２４は格子定数の比ｃ／ａが１．００９２９であったものの、平均結晶粒子径が１．９μｍと大きかった。
In addition, the sample No. outside the scope of the present invention was subjected to heat treatment by an electric furnace without using microwave heating. 19-24, sample no. 19-23 the ratio c / a of the lattice constants as small as 1.00721 or less, a sintered body produced using this powder were those dielectric constant as small as 1 600 or less. Sample No. 24 had a lattice constant ratio c / a of 1.00929, but the average crystal grain size was as large as 1.9 μm.
Claims (3)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2010113359A JP5566183B2 (en) | 2010-05-17 | 2010-05-17 | Dielectric powder and sintered body and capacitor using the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2010113359A JP5566183B2 (en) | 2010-05-17 | 2010-05-17 | Dielectric powder and sintered body and capacitor using the same |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2000363702A Division JP4828692B2 (en) | 2000-11-29 | 2000-11-29 | Method for producing dielectric powder |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2010241682A JP2010241682A (en) | 2010-10-28 |
| JP5566183B2 true JP5566183B2 (en) | 2014-08-06 |
Family
ID=43095133
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2010113359A Expired - Fee Related JP5566183B2 (en) | 2010-05-17 | 2010-05-17 | Dielectric powder and sintered body and capacitor using the same |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP5566183B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10643791B2 (en) | 2018-03-28 | 2020-05-05 | Samsung Electronics Co., Ltd. | Dielectric material, multi-layered capacitors and electronic devices comprising the same |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5715279B1 (en) * | 2014-03-20 | 2015-05-07 | 日本化学工業株式会社 | Method for producing barium titanate powder |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61146709A (en) * | 1984-12-17 | 1986-07-04 | Asahi Chem Ind Co Ltd | Strontium titanate powder |
| JPH0412019A (en) * | 1990-05-01 | 1992-01-16 | Murata Mfg Co Ltd | Preparation of strontium titanate powder |
| JPH0660721A (en) * | 1992-08-04 | 1994-03-04 | Teika Corp | Dielectric porcelain and its manufacture |
| JP3391269B2 (en) * | 1998-01-20 | 2003-03-31 | 株式会社村田製作所 | Dielectric ceramic and its manufacturing method, and multilayer ceramic electronic component and its manufacturing method |
| TW527321B (en) * | 2000-08-09 | 2003-04-11 | Samsung Electro Mech | A method for producing barium titanate based powders by oxalate process |
-
2010
- 2010-05-17 JP JP2010113359A patent/JP5566183B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10643791B2 (en) | 2018-03-28 | 2020-05-05 | Samsung Electronics Co., Ltd. | Dielectric material, multi-layered capacitors and electronic devices comprising the same |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2010241682A (en) | 2010-10-28 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR20100133905A (en) | Sintered material for dielectric substance and process for preparing the same | |
| JP2003002739A (en) | Method for manufacturing barium titanate powder, barium titanate powder and its evaluation method, dielectric ceramic and laminated ceramic capacitor | |
| Chen et al. | Microstructure, dielectric and ferroelectric properties of (1− x) BaTiO 3–x BiYbO 3 ceramics fabricated by conventional and microwave sintering methods | |
| Masin et al. | Microwave hybrid sintering of 0.95 (Mg0. 95Zn0. 05) TiO3-0.05 CaTiO3 ceramics and its microwave dielectric properties | |
| JP5128783B2 (en) | High frequency dielectric materials | |
| WO2020209039A1 (en) | Dielectric inorganic composition | |
| JP4828692B2 (en) | Method for producing dielectric powder | |
| JP5566183B2 (en) | Dielectric powder and sintered body and capacitor using the same | |
| JP3995319B2 (en) | Dielectric material and manufacturing method thereof | |
| TW200424147A (en) | Method for making raw dielectric ceramic powder, dielectric ceramic, and monolithic ceramic capacitor | |
| JP2010163313A (en) | Method of manufacturing crystal-orientated ceramic | |
| JP5207675B2 (en) | Dielectric porcelain and multilayer ceramic capacitor using the same | |
| JP2002015943A (en) | Method for manufacturing dielectric, and the dielectric and capacitor using the dielectric | |
| Liu et al. | Structural evolution and microwave dielectric properties of Ca-substituted ZnTiTa2O8 ceramics with medium permittivity | |
| Deshpande et al. | Characterization of barium titanate: BaTiO 3 (BT) ceramics prepared from sol-gel derived BT powders | |
| JP4830216B2 (en) | Method for producing oxide powder having perovskite structure, oxide powder having perovskite structure, dielectric ceramic and ceramic electronic component | |
| Rocha et al. | High dielectric permittivity in the microwave region of SrBi2Nb2O9 (SBN) added La2O3, PbO and Bi2O3, obtained by mechanical alloying | |
| JPH0542762B2 (en) | ||
| JP4594049B2 (en) | Multilayer ceramic capacitor | |
| Liou et al. | Synthesis and microstructure of SrTiO 3 and BaTiO 3 ceramics by a reaction-sintering process | |
| CN102442825B (en) | Hexagonal type barium titanate powder, producing method thereof, dielectric ceramic composition, electronic component, and producing method of electronic component | |
| JP2005225735A (en) | Production method for dielectric porcelain composition | |
| Manan et al. | Synthesis and Microwave Dielectric Properties of SrLa 4− x Pr x Ti 5 O 17 (0≤ x≤ 4) Ceramics | |
| CN116589277A (en) | Piezoelectric ceramic, ceramic electronic component, and method for manufacturing piezoelectric ceramic | |
| JPH1095663A (en) | Dielectric porcelain preparation |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20111019 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20130205 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20130403 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20131029 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20140106 |
|
| TRDD | Decision of grant or rejection written | ||
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20140520 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20140617 |
|
| R150 | Certificate of patent or registration of utility model |
Ref document number: 5566183 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| LAPS | Cancellation because of no payment of annual fees |