JP4146152B2

JP4146152B2 - Dielectric ceramic composition and ceramic electronic component

Info

Publication number: JP4146152B2
Application number: JP2002111577A
Authority: JP
Inventors: 和巳金田; 敬三川村; 雄一粕谷
Original assignee: Taiyo Yuden Co Ltd
Current assignee: Taiyo Yuden Co Ltd
Priority date: 2002-04-15
Filing date: 2002-04-15
Publication date: 2008-09-03
Anticipated expiration: 2022-04-15
Also published as: JP2003306377A

Description

【０００１】
【発明の属する技術分野】
この発明は、例えばフィルタ、コンデンサ、デュプレクサ、共振器等のセラミック電子部品、特に高周波用のセラミック電子部品とこれに用いられている誘電体磁器組成物に関する。
【０００２】
【従来の技術】
フィルタ、コンデンサ、デュプレクサ、共振器等のセラミック電子部品は、一般に、電極材料と誘電体磁器とを所定の積層構造に形成し、これらを一体的に焼結させて製造されている。積層構造をとることで、小型でありながら高性能の積層セラミック電子部品を実現することが可能になる。
【０００３】
セラミック電子部品の代表例としてはチタン酸バリウム系の誘電体磁器とＮｉ金属の電極材料とを積層構造に形成し、これらを高温で一体的に焼結させて形成した小型・大容量の積層セラミックコンデンサがある。
【０００４】
ところで、近年、高周波を利用した移動体通信機器が広く使用されてきており、そのため、高周波用のセラミック電子部品の高性能化が求められている。
【０００５】
高周波用のセラミック電子部品の特性は、まず、誘電体層の材料として使用される誘電体磁器の誘電特性に大きく影響される。高周波用のセラミック電子部品の誘電体層の材料として使用される誘電体磁器としては、ＢａＯ−ＴｉＯ_２系誘電体磁器、ＢａＯ−Ｎｄ_２Ｏ_３ −ＴｉＯ_２系誘電体磁器、ＭｇＴｉＯ_２ −ＣａＴｉＯ_２系誘電体磁器などが知られている。
【０００６】
また、高周波用のセラミック電子部品の電気特性は、内部電極の材料として使用される金属の導電性にも影響される。すなわち、マイクロ波用積層セラミック電子部品の内部電極の材料としては導電性の良い金属が好ましい。そして、導電性の良い金属としてはＡｇ，Ｃｕ等が挙げられる。
【０００７】
しかし、Ａｇ，Ｃｕ等の金属は融点が低く、９００〜１０５０℃という低温で焼結させる必要があるのに対し、高周波用のセラミック電子部品の誘電体層の材料として使用されている前記誘電体磁器は焼結温度が１２００℃以上とかなり高い。このため、誘電体層と内部電極とを一体的に焼成して焼結させることができず、このままではＡｇ，Ｃｕ等の金属を内部電極の材料として使用することはできない。
【０００８】
Ａｇ，Ｃｕ等の金属を高周波用のセラミック電子部品の内部電極の材料として使用できるようにするためには、誘電体層の材料として使用されている前記誘電体磁器の焼結温度を９００〜１０５０℃程度にしなければならない。
【０００９】
一般に、誘電体磁器の焼結温度を下げる方法の一つとして、誘電体磁器中にガラス成分を添加する方法がある。従来の誘電体磁器の焼結温度は上述したように１２００℃以上と高いので、この誘電体磁器の焼結温度を９００〜１０５０℃程度まで下げるためにはガラス成分をかなり多量に添加しなければならない。
【００１０】
しかし、高周波用のセラミック電子部品の誘電体層の材料として使用されている誘電体磁器中にガラス成分を多量に添加すると誘電体磁器が本来有している誘電特性が低下し、所望の誘電特性が得られなくなってしまう。
【００１１】
そこで、Ａｇ，Ｃｕ等と一体焼成できる程度の低い温度で焼結させることができ、しかも、誘電特性を発現している主相が本来有している誘電特性を充分に引き出すことができる誘電体磁器が求められ、そのような誘電体磁器として、例えば、特開２０００−５８３６７、特開２００１−３１４６８、特開２００１−３１４７０等で公開されたものが提案されている。
【００１２】
特開２０００−５８３６７で公開された積層セラミック電子部品は、誘電体層と内部電極とを積層してなる素体と、該素体の外部に形成され且つ該内部電極に電気的に接続された外部電極とを備え、前記誘電体層は主相とガラス相とを有する誘電体磁器からなり、該主相は誘電特性を発現する成分からなり、該ガラス相にはＡｇが固溶している。
【００１３】
ここで、前記主相がＢａＯ−ｘＴｉＯ_２で表わされる成分からなる場合、ｘは３．４７〜５．７１が好ましい。また、前記主相がＢａＯ−ｙＮｄ_２Ｏ_３−ｚＴｉＯ_２で表わされる成分からなる場合、ｙは０．６５〜１．４２、ｚは２．２９〜５．４２が好ましい。
【００１４】
この発明によれば、ガラス相にＡｇを固溶させたので、焼成時におけるガラスの粘性が低下し、より低い焼成温度での焼結が可能となり、焼結温度の高い誘電材料（主相）をその誘電特性を低下させることなく低い温度で焼結させることができ、従って、導電性の良いＡｇ，Ｃｕ等を内部電極の材料として使用することができ、その結果、高周波特性の良い積層セラミック電子部品を提供することができる。
【００１５】
特開２００１−３１４６８で公開された誘電体磁器組成物は、一般式ｘＢａＯ・ｙＮｄ_２Ｏ_３・ｚＴｉＯ_２（ただし、６≦ｘ≦２３、１３≦ｙ≦３０、６４≦ｚ≦６８、ｘ＋ｙ＋ｚ＝１００の関係を有する）で表される主成分に対して、副成分としてＣｕ酸化物をＣｕＯ換算にて０．１〜３．０重量％、Ｚｎ酸化物をＺｎＯ換算にて０．１〜４．０重量％、Ｂ酸化物をＢ_２Ｏ_３換算にて０．１〜３．０重量％、Ａｇを０．３〜１．５重量％の範囲で含有したものからなる。
【００１６】
この発明によれば、所定の組成範囲にあるＢａＯ−Ｎｄ_２Ｏ_３−ＴｉＯ_２系主成分とともに、Ｃｕ酸化物、Ｚｎ酸化物、Ｂ酸化物およびＡｇが含有されるので、誘電特性を低下させることなく、ＡｇまたはＡｇを主成分とする合金の融点以下で焼結可能な誘電体磁器組成物が得られる。
【００１７】
これにより、低抵抗であるＡｇやＡｇ合金のような融点の低い金属を内部導体として電子部品を構成することが可能となり、結果として高周波デバイスの諸特性の向上、小型化、低コスト化が可能となる。
【００１８】
さらに、副成分として含有されるＡｇが、内部導体から誘電体内へのＡｇ拡散を抑制するので、誘電特性の不均一性が防止され、かつ、内部導体と誘電体間の空隙の発生や、内部導体の外部接続部位における引き込み発生が防止される。
【００１９】
特開２００１−３１４７０で公開された誘電体磁器組成物は、一般式ｘＢａＯ・ｙＮｄ_２Ｏ_３・ｚＴｉＯ_２（ただし、６≦ｘ≦２３、１３≦ｙ≦３０、６４≦ｚ≦６８、ｘ＋ｙ＋ｚ＝１００の関係を有する）で表される主成分に対して、副成分としてＣｕ酸化物をＣｕＯ換算にて０．１〜３．０重量％、ガラス組成物を２．０〜１０重量％、Ａｇを０．３〜１．５重量％の範囲で含有するものとし、上記のガラス組成物は以下の組成の範囲にあるものとする。
【００２０】
５重量％≦ＳｉＯ_２≦１５重量％１５重量％≦Ｂ_２Ｏ_３≦２５重量％５０重量％≦（Ｍｇ＋ＢａＯ＋ＳｒＯ＋ＺｎＯ＋ＣａＯ）≦８０重量％９０重量％≦（ＳｉＯ_２＋Ｂ_２Ｏ_３＋ＭｇＯ＋ＢａＯ＋ＳｒＯ＋ＺｎＯ＋ＣａＯ）≦１００重量％
【００２１】
この発明によれば、所定の組成範囲にあるＢａＯ−Ｎｄ_２Ｏ_３−ＴｉＯ_２系主成分とともに、Ｃｕ酸化物、所定の組成範囲にあるガラス組成物およびＡｇが含有されるので、誘電特性を低下させることなく、ＡｇまたはＡｇを主成分とする合金の融点以下で焼結可能な誘電体磁器組成物が得られる。
【００２２】
これにより、低抵抗であるＡｇやＡｇ合金のような融点の低い金属を内部導体として電子部品を構成することが可能となり、結果として高周波デバイスの諸特性の向上、小型化、低コスト化が可能となる。
【００２３】
さらに、副成分として含有されるＡｇが、内部導体から誘電体内へのＡｇ拡散を抑制するので、誘電特性の不均一性が防止され、かつ、内部導体と誘電体間の空隙の発生や、内部導体の外部接続部位における引き込み発生が防止される。
【００２４】
【発明が解決しようとする課題】
ところで、近年における電子回路の小型化、高密度化の流れはとどまるところがなく、高周波用のセラミック電子部品についても更なる小型化が求められ、小型化のための種々の工夫が回路設計上においてなされている。
【００２５】
また、高周波用のセラミック電子部品の小型化に関しては積層セラミック電子部品で使用されている誘電体磁器組成物の誘電率の大きさも大きく影響しており、誘電率が大きい方がセラミック電子部品を小型化し易いので、ここで使用される誘電体磁器組成物の更なる高誘電率化が求められている。
【００２６】
この発明は、従来よりも更に小型化した高周波用のセラミック電子部品とこれに用いることのできる高誘電率の誘電体磁器組成物を提供することを目的とする。
【００２７】
【課題を解決するための手段】
この発明に係る誘電体磁器組成物は主相とガラス相とからなり、該主相は誘電特性を発現する誘電体成分からなり、該誘電体成分にはＢｉが固溶し、該主相及び／又は該ガラス相にはＡｇが固溶しており、この発明に係るセラミック電子部品は、誘電体層と内部電極とを積層してなる素体と、該素体の外部に形成され且つ該内部電極に電気的に接続された外部電極とを備え、前記誘電体層は前記誘電体磁器組成物からなるものである。
【００２８】
ここで、誘電特性を発現する主相としてはＢａＯ−ＴｉＯ_２−Ｎｄ_２Ｏ_３で表される成分を主成分として使用することができる。この場合、ＢａＯ−ＴｉＯ_２−Ｎｄ_２Ｏ_３系の成分をｘＢａＯ−ｙＴｉＯ_２−ｚＮｄ_２Ｏ_３で表わした場合、ｘは１２≦ｘ≦１９、ｙは６４≦ｙ≦７４、ｚは９≦ｚ≦１９の範囲が好ましい。
【００２９】
ｘを１２≦ｘ≦１９の範囲としたのは、ｘが１２未満になると所望の誘電率が得られなくなったり、焼結性が低下し、ｘが１９を越えると電気特性であるτｆが＋側に大きくシフトしたり、所望のＱ値が得られなくなるからである。
【００３０】
ｙを６４≦ｙ≦７４の範囲としたのは、ｙが６４未満になると電気特性であるτｆが−側にシフトしたり、所望のＱ値が得られなくなり、ｙが７４を越えると焼結性が低下したり、電気特性であるτｆが＋側にシフトしてしまうからである。
【００３１】
ｚを９≦ｚ≦１９の範囲としたのは、ｚが９未満になると電気特性であるτｆが＋側にシフトしたり、所望のＱ値が得られなくなり、ｚが１９を越えると所望の誘電率が得られず、所望のＱ値が得られなくなり、また焼結性が低下するからである。
【００３２】
また、主相にはＢｉがＢｉ_２Ｏ_３換算で主相の主成分に対して１２〜２４ｗｔ％の割合で固溶されている。ＢｉがＢｉ_２Ｏ_３換算で主相の主成分に対して１２ｗｔ％未満になると所望の誘電率が得られず、ＢｉがＢｉ_２Ｏ_３換算で主相の主成分に対して２４ｗｔ％を超えると焼結性が低下し、所望の誘電率が得られず、またＱが低くなるからである。
【００３３】
また、ＡｇはＡｇ_２Ｏ換算で主相の主成分に対して１〜４ｗｔ％含有されているのが好ましい。Ａｇが主相の主成分に対して１ｗｔ％未満になると焼結性が低下し、内部電極端部に空隙ができ、Ａｇが主相の主成分に対して４ｗｔ％を越えるとＡｇが析出して絶縁抵抗ＩＲが劣化するからである。
【００３４】
また、前記ガラス相は前記主相の主成分に対して５〜１２ｗｔ％含有されているのが好ましい。ガラス相が主相の主成分に対して５ｗｔ％未満になると焼結できなくなり、１２ｗｔ％を越えると所望の誘電率が得られず、Ｑが悪化してしまうからである。
【００３５】
また、ＰｂはＰｂＯ換算で主相の主成分に対して５ｗｔ％以下であれば含有されていてもよい。Ｐｂを添加しなくても所望の誘電体磁器組成物は得られるが、Ｐｂが主相の主成分に対して５ｗｔ％を超えるとτｆが大きくシフトしてしまうからである。
【００３６】
また、ＣｕはＣｕＯ換算で主相の主成分に対して０〜２ｗｔ％含有されていてもよい。Ｃｕを添加しなくても所望の誘電体磁器組成物は得られるが、Ｃｕが主相の主成分に対して２ｗｔ％を超えるとτｆが−側に大きくシフトしてしまうからである。
【００３７】
なお、Ｂａ，Ｔｉ，Ｎｄ，Ｂｉ，Ｐｂは主相の成分であるが、焼成によりこれらの成分がガラス相に拡散する可能性があるので、これらの成分がガラス相に微量含まれていてもよい。
【００３８】
【実施例】
実施例１まず、主相形成成分として、ＢａＯ、ＴｉＯ_２、Ｎｄ_２Ｏ_３、Ｂｉ_２Ｏ_３，ＰｂＯを表１の試料番号１〜６に示す配合割合で各々秤量した。ここで、Ｂｉ_２Ｏ_３は０〜３０ｗｔ％の範囲で変化させた。また、各化合物は純度９９．０％以上のものを使用した。
【００３９】
【表１】

【００４０】
次に、これらの化合物を水とともにボールミルに入れ、湿式で１５時間攪拌混合し、得られた泥漿をバットに空け、乾燥機に入れて１５０℃で２４時間乾燥した。そして、得られた乾燥物を粉砕機で粉砕して３２５メッシュの粉体とし、この粉体を大気中において１０５０℃で２時間仮焼して誘電特性を発現する主相の成分粉末を得た。
【００４１】
また、ガラス形成成分として、Ｂ_２Ｏ_３：ＳｉＯ_２：ＺｎＯ＝１：５：４のホウケイ酸亜鉛ガラスとＣｕＯ及びＡｇ_２Ｏを表１の試料番号１〜６に示す配合割合で各々秤量した。ここで、各化合物は純度９９．０％以上のものを使用した。
【００４２】
次に、前記主相形成成分の粉末とガラス形成成分の粉末を水とともにボールミルに入れ、湿式で１５時間混合し、得られた泥漿をバットに空け、乾燥機に入れて１５０℃で２４時間乾燥した。そして、得られた乾燥物を粉砕機で粉砕して３２５メッシュのセラミック粉体とし、このセラミック粉体を有機バインダとともにボールミルに入れて混合し、磁器原料のスラリーを作成した。
【００４３】
次に、このスラリーを真空脱泡機に入れて脱泡し、このスラリーをリバースロールコータに入れ、ポリエステルフィルム上にこのスラリーからなる薄膜を形成し、この薄膜をポリエステルフィルム上で加熱して乾燥させ、打ち抜いて所定の大きさのグリーンシートを得た。
【００４４】
一方、銀粉末を主成分とする内部電極用の導電性ペーストを形成し、上記グリーンシートにこの導電性ペーストからなる５０個の導電パターンを印刷し、乾燥させた。
【００４５】
次に、上記導電パターンの印刷面を上にして複数枚のグリーンシートを積層した。この際、隣接する上下のシートにおいて、その印刷面がパターンの長手方向に約半分程ずれるように配置した。更に、この積層物の上下両面に導電パターンの印刷の施されていないグリーンシートを積層した。そして、この積層物を厚さ方向に圧力を加えて圧着させ、その後、この積層物を導電パターン毎に裁断し、チップ状の積層体５０個を得た。
【００４６】
次に、この積層チップを電気炉に入れ、大気雰囲気中において９３０℃で３時間焼成し、チップ状の素体を得た。そして、このチップ状の素体の端部に一対の外部電極を焼き付け、積層セラミックコンデンサを得た。
【００４７】
次に、この積層セラミックコンデンサの電気特性（εｒ，Ｑ，τｆ）を測定したところ、表２に示す通りであった。
【００４８】
【表２】

【００４９】
表１，２に示す結果から、試料番号３〜５に示すように主相に対するＢｉの割合がＢｉ_２Ｏ_３換算で１２〜２４ｗｔ％の場合は所望の焼結性及び電気特性のものが得られるが、試料番号１，２に示すように主相に対するＢｉの割合がＢｉ_２Ｏ_３換算で１２ｗｔ％未満になると所望の誘電率のものが得られなくなり、試料番号６に示すように主相に対するＢｉの割合がＢｉ_２Ｏ_３換算で２４ｗｔ％を超えると９３０℃の焼成で所望の密度に焼結せず、所望の誘電率及び所望のＱのものが得られなくなることがわかる。
【００５０】
実施例２表３に示すようにＡｇ_２Ｏの添加量及びＣｕＯの添加量を変化させた以外は実施例１と同様の条件で同様の実験をしたところ、表４に示すような結果が得られた。
【００５１】
【表３】

【００５２】
【表４】

【００５３】
表３，４に示す結果から、試料番号９〜１２に示すように主相に対するＡｇの割合がＡｇ_２Ｏ換算で１〜４ｗｔ％の場合は所望の焼結性及び電気特性のものが得られるが、試料番号７，８に示すように主相に対するＡｇの割合がＡｇ_２Ｏ換算で１ｗｔ％未満になると９３０℃の焼成で所望の密度に焼結せず、内部電極端部に空隙ができ、試料番号１３に示すように主相に対するＡｇの割合がＡｇ_２Ｏ換算で４ｗｔ％を超えるとＩＲが劣化することがわかる。
【００５４】
実施例３表５に示すようにＰｂＯの添加量を変化させた以外は実施例１と同様の条件で同様の実験をしたところ、表６に示すような結果が得られた。
【００５５】
【表５】

【００５６】
【表６】

【００５７】
表５，６に示す結果から、試料番号１９〜２２に示すように主相に対するＰｂの割合がＰｂＯ換算で０〜５ｗｔ％の場合は所望の焼結性及び電気特性のものが得られるが、試料番号２３に示すように主相に対するＰｂの割合がＰｂＯ換算で５ｗｔ％を超えるとτｆが大きくシフトすることがわかる。
【００５８】
実施例４表７に示すようにガラスの添加量を変化させた以外は実施例１と同様の条件で同様の実験をしたところ、表８に示すような結果が得られた。
【００５９】
【表７】

【００６０】
【表８】

【００６１】
表７，８に示す結果から、試料番号２６〜２８に示すように主相に対するガラスの割合が５〜１２ｗｔ％の場合は所望の焼結性及び電気特性のものが得られるが、試料番号２４、２５に示すように主相に対するガラスの割合が５ｗｔ％未満になると９３０℃の焼成で所望の密度に焼結せず、試料番号２９に示すように主相に対するガラスの割合が１２ｗｔ％を超えると所望の誘電率及び所望のＱのものが得られなくなることがわかる。
【００６２】
実施例５表９に示すように主相形成成分であるＢａＯ，ＴｉＯ_２，Ｎｄ_２Ｏ_３の割合を変化させた以外は実施例１と同様の条件で同様の実験をしたところ、表１０に示すような結果が得られた。
【００６３】
【表９】

【００６４】
【表１０】

【００６５】
表９，１０に示す結果から、試料番号３１〜３３に示すようにｘが１２〜１９の場合は所望の焼結性及び電気特性のものが得られるが、試料番号３０に示すように、ｘが１２未満になると所望の誘電率のものが得られなくなったり、９３０℃の焼成で所望の密度に焼結せず、試料番号３４に示すように、ｘが１９を越えると電気特性であるτｆが＋側に大きくシフトしたり、所望のＱ値のものが得られなくなることがわかる。
【００６６】
また、表９，１０に示す結果から、試料番号３６，３７に示すようにｙが６４〜７４の場合は所望の焼結性及び電気特性のものが得られるが、試料番号３５に示すように、ｙが６４未満になると電気特性であるτｆが−側にシフトしたり、所望のＱ値のものが得られなくなり、試料番号３８に示すように、ｙが７４を越えると９３０℃の焼成で所望の密度に焼結せず、電気特性であるτｆが＋側にシフトすることがわかる。
【００６７】
また、表９，１０に示す結果から、試料番号４０，４１に示すようにｚが９〜１９の場合は所望の焼結性及び電気特性のものが得られるが、試料番号３９に示すように、ｚが９未満になると電気特性である所望のＱ値のものが得られなくなったり、τｆが＋側にシフトし、試料番号４２に示すように、ｚが１９を越えると所望の誘電率や所望のＱ値のものが得られなくなり、９３０℃の焼成で所望の密度に焼結しなくなることがわかる。
【００６８】
【発明の効果】
この発明は、誘電体層を形成している誘電体磁器組成物の主相にＢｉ_２Ｏ_３換算で１２〜２４重量％のＢｉが固溶しているので、誘電体磁器組成物の誘電率が従来のものより高くなり、その結果、従来より小型のセラミック電子部品を得ることができるという効果がある。
【００６９】
また、この発明によれば、ガラス相にＡｇが固溶しているので、焼成時におけるガラスの粘度が低下し、より低い焼成温度での焼結が可能となり、焼結温度の高い誘電体材料（主相）をその誘電特性を低下させることなく低い温度で焼結させることができ、従って、導電性の良いＡｇ，Ｃｕ等を内部電極の材料として使用することができ、その結果、高周波特性の良いセラミック電子部品を得ることができるという効果がある。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a ceramic electronic component such as a filter, a capacitor, a duplexer, and a resonator, and more particularly to a high frequency ceramic electronic component and a dielectric ceramic composition used therefor.
[0002]
[Prior art]
Ceramic electronic components such as filters, capacitors, duplexers, and resonators are generally manufactured by forming an electrode material and a dielectric ceramic in a predetermined laminated structure and sintering them together. By adopting a laminated structure, it is possible to realize a high-performance multilayer ceramic electronic component that is small in size.
[0003]
A typical example of ceramic electronic components is a small-sized and large-capacity multilayer ceramic formed by laminating a barium titanate-based dielectric ceramic and an electrode material made of Ni metal and sintering them integrally at a high temperature. There is a capacitor.
[0004]
By the way, in recent years, mobile communication devices using high frequency have been widely used. Therefore, high performance of ceramic electronic components for high frequency has been demanded.
[0005]
The characteristics of high-frequency ceramic electronic components are greatly influenced by the dielectric characteristics of the dielectric ceramic used as the material of the dielectric layer. Examples of the dielectric ceramic used as the material of the dielectric layer of the high frequency ceramic electronic component include BaO—TiO ₂ dielectric ceramic, BaO—Nd ₂ O ₃ —TiO ₂ dielectric ceramic, and MgTiO ₂ —CaTiO _2. Related dielectric ceramics are known.
[0006]
In addition, the electrical characteristics of high-frequency ceramic electronic components are also affected by the conductivity of the metal used as the material for the internal electrodes. That is, a metal having good conductivity is preferable as the material of the internal electrode of the multilayer ceramic electronic component for microwaves. Examples of the metal having good conductivity include Ag and Cu.
[0007]
However, metals such as Ag and Cu have a low melting point and need to be sintered at a low temperature of 900 to 1050 ° C., whereas the dielectric used as a dielectric layer material for high frequency ceramic electronic components Porcelain has a fairly high sintering temperature of 1200 ° C or higher. For this reason, the dielectric layer and the internal electrode cannot be integrally fired and sintered, and a metal such as Ag or Cu cannot be used as a material for the internal electrode as it is.
[0008]
In order to make it possible to use a metal such as Ag or Cu as a material for internal electrodes of high-frequency ceramic electronic components, the sintering temperature of the dielectric ceramic used as the material for the dielectric layer is set to 900 to 1050. Must be around ℃.
[0009]
In general, one method for lowering the sintering temperature of a dielectric ceramic is to add a glass component to the dielectric ceramic. Since the sintering temperature of the conventional dielectric ceramic is as high as 1200 ° C. or more as described above, in order to lower the sintering temperature of this dielectric ceramic to about 900 to 1050 ° C., a considerable amount of glass component must be added. Don't be.
[0010]
However, if a large amount of glass component is added to the dielectric ceramic used as the material of the dielectric layer of high-frequency ceramic electronic components, the dielectric characteristics inherent in the dielectric ceramic will be reduced, and the desired dielectric characteristics will be reduced. Can no longer be obtained.
[0011]
Therefore, a dielectric that can be sintered at a low temperature that can be integrally fired with Ag, Cu, etc., and that can sufficiently bring out the inherent dielectric properties of the main phase that exhibits dielectric properties. Porcelains are required, and as such dielectric ceramics, for example, those disclosed in Japanese Patent Application Laid-Open Nos. 2000-58367, 2001-31468, 2001-31470, and the like have been proposed.
[0012]
A multilayer ceramic electronic component disclosed in Japanese Patent Application Laid-Open No. 2000-58367 has an element body formed by laminating a dielectric layer and an internal electrode, and is formed outside the element body and electrically connected to the internal electrode. An external electrode, and the dielectric layer is made of a dielectric ceramic having a main phase and a glass phase, the main phase is made of a component that exhibits dielectric properties, and Ag is dissolved in the glass phase. .
[0013]
Here, when the main phase is composed of a component represented by BaO—xTiO ₂ , x is preferably 3.47 to 5.71. Moreover, if composed of components which the main phase is represented by _{_{_{BaO-yNd 2 O 3 -zTiO 2}}} , y is from .65 to 1.42, z is preferably from 2.29 to 5.42.
[0014]
According to this invention, since Ag is dissolved in the glass phase, the viscosity of the glass at the time of firing is reduced, and sintering at a lower firing temperature is possible, and a dielectric material (main phase) having a high sintering temperature. Can be sintered at a low temperature without deteriorating its dielectric properties, and therefore, Ag, Cu, etc. having good conductivity can be used as a material for internal electrodes, and as a result, a multilayer ceramic having good high frequency properties. Electronic components can be provided.
[0015]
The dielectric ceramic composition disclosed in Japanese Patent Laid-Open No. 2001-31468 has a general formula xBaO · yNd ₂ O ₃ · zTiO ₂ (where 6 ≦ x ≦ 23, 13 ≦ y ≦ 30, 64 ≦ z ≦ 68, x + y + z = 100 as a subcomponent, Cu oxide is 0.1 to 3.0% by weight in terms of CuO, and Zn oxide is 0.1 to 4 in terms of ZnO. .0 wt%, 0.1 to 3.0 wt% of B oxide in terms _of _B 2 _{O 3,} consist of those containing in a range of Ag 0.3 to 1.5 wt%.
[0016]
According to the present invention, since Cu oxide, Zn oxide, B oxide and Ag are contained together with the BaO—Nd ₂ O ₃ —TiO ₂ main component in the predetermined composition range, the dielectric characteristics are lowered. Thus, a dielectric ceramic composition that can be sintered below the melting point of Ag or an alloy containing Ag as a main component is obtained.
[0017]
As a result, it is possible to configure electronic components using low resistance metal such as Ag or Ag alloy with low melting point as the inner conductor, and as a result, various characteristics of high-frequency devices can be improved, downsized, and reduced in cost. It becomes.
[0018]
Furthermore, since Ag contained as a subcomponent suppresses Ag diffusion from the inner conductor into the dielectric, non-uniformity of the dielectric characteristics is prevented, and generation of voids between the inner conductor and the dielectric, Pulling-in at the external connection portion of the conductor is prevented.
[0019]
The dielectric ceramic composition disclosed in Japanese Patent Laid-Open No. 2001-31470 has a general formula xBaO · yNd ₂ O ₃ · zTiO ₂ (where 6 ≦ x ≦ 23, 13 ≦ y ≦ 30, 64 ≦ z ≦ 68, x + y + z = 100 to 100 wt.%, Cu oxide as a subcomponent is 0.1 to 3.0 wt% in terms of CuO, glass composition is 2.0 to 10 wt%, Ag In the range of 0.3 to 1.5% by weight, and the glass composition is in the following composition range.
[0020]
5 wt% ≦ SiO ₂ ≦ 15 wt% 15 wt% ≦ _B 2 _{O 3} ≦ 25 wt% 50 wt% ≦ (Mg + BaO + SrO + ZnO + CaO) ≦ 80 wt% 90 _{_{_{wt% ≦ (SiO 2 + B 2}}} O 3 + MgO + BaO + SrO + ZnO + CaO) ≦ 100 wt%
[0021]
According to this invention, since the Cu oxide, the glass composition in the predetermined composition range, and Ag are contained together with the BaO—Nd ₂ O ₃ —TiO ₂ main component in the predetermined composition range, the dielectric characteristics are improved. A dielectric ceramic composition that can be sintered at a temperature equal to or lower than the melting point of Ag or an alloy containing Ag as a main component without reduction is obtained.
[0022]
As a result, it is possible to configure electronic components using low resistance metal such as Ag or Ag alloy with low melting point as the inner conductor, and as a result, various characteristics of high-frequency devices can be improved, downsized, and reduced in cost. It becomes.
[0023]
Furthermore, since Ag contained as a subcomponent suppresses Ag diffusion from the inner conductor into the dielectric, non-uniformity of the dielectric characteristics is prevented, and generation of voids between the inner conductor and the dielectric, Pulling-in at the external connection portion of the conductor is prevented.
[0024]
[Problems to be solved by the invention]
By the way, the trend of downsizing and increasing the density of electronic circuits in recent years is not limited, and further downsizing of ceramic electronic parts for high frequency is required, and various devices for downsizing are made in circuit design. ing.
[0025]
In addition, regarding the downsizing of ceramic electronic components for high frequency use, the dielectric constant of the dielectric ceramic composition used in the multilayer ceramic electronic component has a large influence, and the ceramic electronic component is smaller when the dielectric constant is larger. Therefore, the dielectric ceramic composition used here is required to have a higher dielectric constant.
[0026]
An object of the present invention is to provide a high-frequency ceramic electronic component that is further miniaturized than before and a dielectric ceramic composition having a high dielectric constant that can be used therefor.
[0027]
[Means for Solving the Problems]
The dielectric ceramic composition according to the present invention is composed of a main phase and a glass phase, the main phase is composed of a dielectric component that exhibits dielectric properties, Bi is dissolved in the dielectric component, and the main phase and In the glass phase, Ag is solid-solved, and the ceramic electronic component according to the present invention includes an element body formed by laminating a dielectric layer and an internal electrode, and formed on the outside of the element body. An external electrode electrically connected to the internal electrode, and the dielectric layer is made of the dielectric ceramic composition.
[0028]
Here, a component represented by BaO—TiO ₂ —Nd ₂ O ₃ can be used as a main component as a main phase that exhibits dielectric characteristics. In this case, when the BaO—TiO ₂ —Nd ₂ O ₃ -based component is represented by xBaO—yTiO ₂ —zNd ₂ O ₃ , x is 12 ≦ x ≦ 19, y is 64 ≦ y ≦ 74, and z is 9 ≦ A range of z ≦ 19 is preferred.
[0029]
The reason why x is in the range of 12 ≦ x ≦ 19 is that when x is less than 12, a desired dielectric constant cannot be obtained or the sinterability decreases, and when x exceeds 19, τf, which is an electrical property, is + This is because a large shift to the side or a desired Q value cannot be obtained.
[0030]
The reason why y is in the range of 64 ≦ y ≦ 74 is that when y is less than 64, τf, which is an electrical characteristic, shifts to the negative side, or a desired Q value cannot be obtained, and when y exceeds 74, sintering is performed. This is because the property decreases or τf, which is an electrical characteristic, shifts to the + side.
[0031]
The reason why z is in the range of 9 ≦ z ≦ 19 is that when z is less than 9, τf, which is an electrical characteristic, shifts to the + side, or a desired Q value cannot be obtained. This is because the dielectric constant cannot be obtained, the desired Q value cannot be obtained, and the sinterability is lowered.
[0032]
Further, Bi is dissolved in the main phase at a rate of 12 to 24 wt% with respect to the main component of the main phase in terms of Bi ₂ O ₃ . When Bi is less than 12 wt% with respect to the main component of the main phase in terms of Bi ₂ O ₃ , a desired dielectric constant cannot be obtained, and Bi exceeds 24 wt% with respect to the main component of the main phase in terms of Bi ₂ O _3. This is because the sinterability is lowered, the desired dielectric constant cannot be obtained, and the Q is lowered.
[0033]
Further, Ag is preferably contained 1～4Wt% with respect to the main component of the main phase in the Ag ₂ O conversion. When Ag is less than 1 wt% with respect to the main component of the main phase, the sinterability is reduced, and voids are formed at the end of the internal electrode, and when Ag exceeds 4 wt% with respect to the main component of the main phase , Ag precipitates. This is because the insulation resistance IR deteriorates.
[0034]
Moreover, it is preferable that the said glass phase contains 5-12 wt% with respect to the main component of the said main phase. This is because if the glass phase is less than 5 wt% with respect to the main component of the main phase , sintering cannot be performed, and if it exceeds 12 wt%, a desired dielectric constant cannot be obtained and Q deteriorates.
[0035]
Further, Pb may be contained as long as 5 wt% or less with respect to the main component of the main phase in terms of PbO. This is because a desired dielectric ceramic composition can be obtained without adding Pb, but when Pb exceeds 5 wt% with respect to the main component of the main phase , τf is greatly shifted.
[0036]
Cu may be contained in an amount of 0 to 2 wt% with respect to the main component of the main phase in terms of CuO. This is because a desired dielectric ceramic composition can be obtained without adding Cu, but when Cu exceeds 2 wt% with respect to the main component of the main phase , τf is greatly shifted to the-side.
[0037]
Ba, Ti, Nd, Bi, and Pb are components of the main phase, but since these components may diffuse into the glass phase by firing, even if these components are contained in a small amount in the glass phase. Good.
[0038]
【Example】
Example 1 First, BaO, TiO ₂ , Nd ₂ O ₃ , Bi ₂ O ₃ , and PbO were weighed as the main phase forming components at the blending ratios shown in sample numbers 1 to 6 in Table 1, respectively. Here, Bi ₂ O ₃ was changed in the range of 0 to ₃₀ wt%. Each compound was used with a purity of 99.0% or more.
[0039]
[Table 1]

[0040]
Next, these compounds were placed in a ball mill together with water and mixed with stirring for 15 hours in a wet manner. The resulting slurry was poured into a vat and placed in a dryer and dried at 150 ° C. for 24 hours. The obtained dried product was pulverized by a pulverizer to obtain a 325 mesh powder, and this powder was calcined in the atmosphere at 1050 ° C. for 2 hours to obtain a main phase component powder exhibiting dielectric properties. .
[0041]
Further, as a glass-forming _{_{_{component, B 2 O 3: SiO 2}}} : ZnO = 1: 5: 4 of the borosilicate zinc glass and CuO and Ag ₂ O were each weighed in proportions shown in sample No. 1-6 in Table 1 . Here, each compound having a purity of 99.0% or more was used.
[0042]
Next, the main phase-forming component powder and the glass-forming component powder are placed in a ball mill together with water, mixed by wet for 15 hours, and the resulting slurry is poured into a vat and dried in a dryer at 150 ° C. for 24 hours. did. The obtained dried product was pulverized with a pulverizer to form a 325 mesh ceramic powder, and this ceramic powder was mixed with an organic binder in a ball mill to prepare a porcelain raw material slurry.
[0043]
Next, the slurry is put in a vacuum defoaming machine, defoamed, the slurry is put in a reverse roll coater, a thin film made of the slurry is formed on the polyester film, and the thin film is heated and dried on the polyester film. And punched to obtain a green sheet of a predetermined size.
[0044]
On the other hand, a conductive paste for internal electrodes containing silver powder as a main component was formed, and 50 conductive patterns made of this conductive paste were printed on the green sheet and dried.
[0045]
Next, a plurality of green sheets were laminated with the printed surface of the conductive pattern facing up. At this time, the upper and lower sheets adjacent to each other were arranged so that their printing surfaces were shifted by about half in the longitudinal direction of the pattern. Furthermore, the green sheet in which the conductive pattern was not printed was laminated | stacked on both upper and lower surfaces of this laminated body. Then, the laminate was pressure-bonded by applying pressure in the thickness direction, and then the laminate was cut for each conductive pattern to obtain 50 chip-like laminates.
[0046]
Next, this laminated chip was put in an electric furnace and baked at 930 ° C. for 3 hours in an air atmosphere to obtain a chip-shaped element. Then, a pair of external electrodes was baked on the end of the chip-shaped element body to obtain a multilayer ceramic capacitor.
[0047]
Next, the electrical characteristics (εr, Q, τf) of this multilayer ceramic capacitor were measured and as shown in Table 2.
[0048]
[Table 2]

[0049]
From the results shown in Tables 1 and 2, when the ratio of Bi to the main phase is 12 to 24 wt% in terms of Bi ₂ O ₃ as shown in Sample Nos. 3 to 5, the desired sinterability and electrical characteristics are obtained. However, when the ratio of Bi to the main phase is less than 12 wt% in terms of Bi ₂ O ₃ as shown in sample numbers 1 and 2, a desired dielectric constant cannot be obtained. ratio of Bi with respect to that Bi ₂ O ₃ without sintering the desired density in the firing of 24 wt% by weight, 930 ° C. in terms of apparent may not be obtained as desired dielectric constant and desired Q.
[0050]
Example 2 As shown in Table 3, when the same experiment was conducted under the same conditions as in Example 1 except that the addition amount of Ag ₂ O and the addition amount of CuO were changed, the results shown in Table 4 were obtained. It was.
[0051]
[Table 3]

[0052]
[Table 4]

[0053]
From the results shown in Tables 3 and 4, when the ratio of Ag to the main phase is 1 to 4 wt% in terms of Ag ₂ O as shown in sample numbers 9 to 12, the desired sinterability and electrical characteristics can be obtained. However, as shown in Sample Nos. 7 and 8, when the ratio of Ag to the main phase is less than 1 wt% in terms of Ag ₂ O, sintering at 930 ° C. does not sinter to the desired density, and voids are formed at the ends of the internal electrodes. As shown in Sample No. 13, it can be seen that IR deteriorates when the ratio of Ag to the main phase exceeds 4 wt% in terms of Ag ₂ O.
[0054]
Example 3 As shown in Table 5, when the same experiment was performed under the same conditions as in Example 1 except that the amount of PbO added was changed, the results shown in Table 6 were obtained.
[0055]
[Table 5]

[0056]
[Table 6]

[0057]
From the results shown in Tables 5 and 6, when the ratio of Pb to the main phase is 0 to 5 wt% in terms of PbO as shown in sample numbers 19 to 22, the desired sinterability and electrical characteristics can be obtained. As shown in sample number 23, it can be seen that when the ratio of Pb to the main phase exceeds 5 wt% in terms of PbO, τf shifts greatly.
[0058]
Example 4 As shown in Table 7, when the same experiment was performed under the same conditions as in Example 1 except that the amount of glass added was changed, the results shown in Table 8 were obtained.
[0059]
[Table 7]

[0060]
[Table 8]

[0061]
From the results shown in Tables 7 and 8, when the ratio of the glass to the main phase is 5 to 12 wt% as shown in Sample Nos. 26 to 28, desired sinterability and electrical characteristics can be obtained. When the ratio of glass to the main phase is less than 5 wt% as shown in FIG. 25, the glass is not sintered to a desired density by firing at 930 ° C., and the ratio of glass to the main phase exceeds 12 wt% as shown in sample number 29 It can be seen that the desired dielectric constant and desired Q cannot be obtained.
[0062]
Example 5 As shown in Table 9, when a similar experiment was performed under the same conditions as in Example 1 except that the ratio of BaO, TiO ₂ and Nd ₂ O ₃ as main phase forming components was changed, Table 10 shows The results shown were obtained.
[0063]
[Table 9]

[0064]
[Table 10]

[0065]
From the results shown in Tables 9 and 10, when x is 12 to 19 as shown in sample numbers 31 to 33, desired sinterability and electrical characteristics are obtained, but as shown in sample number 30, x If it is less than 12, a product having a desired dielectric constant cannot be obtained, or it is not sintered to a desired density by firing at 930 ° C., and as shown in sample number 34, when x exceeds 19, τf, which is an electrical property It can be seen that the value shifts greatly to the + side, and a desired Q value cannot be obtained.
[0066]
Further, from the results shown in Tables 9 and 10, when y is 64 to 74 as shown in sample numbers 36 and 37, desired sinterability and electrical characteristics are obtained, but as shown in sample number 35 When y is less than 64, τf, which is an electrical characteristic, shifts to the minus side, or a desired Q value cannot be obtained. As shown in sample number 38, when y exceeds 74, firing at 930 ° C. It can be seen that the electrical characteristics τf shifts to the + side without sintering to the desired density.
[0067]
Further, from the results shown in Tables 9 and 10, when z is 9 to 19 as shown in sample numbers 40 and 41, desired sinterability and electrical characteristics can be obtained, but as shown in sample number 39 When z is less than 9, a desired Q value that is an electrical characteristic cannot be obtained, or τf shifts to the + side. As shown in sample number 42, when z exceeds 19, the desired dielectric constant or It turns out that the thing of the desired Q value is no longer obtained, and it does not sinter to a desired density by baking at 930 ° C.
[0068]
【The invention's effect】
In the present invention, since 12 to 24% by weight of Bi in terms of Bi ₂ O ₃ is dissolved in the main phase of the dielectric ceramic composition forming the dielectric layer, the dielectric constant of the dielectric ceramic composition As a result, there is an effect that a ceramic electronic component smaller than the conventional one can be obtained.
[0069]
In addition, according to the present invention, since Ag is dissolved in the glass phase, the viscosity of the glass at the time of firing is reduced, enabling sintering at a lower firing temperature, and a dielectric material having a high sintering temperature. (Main phase) can be sintered at a low temperature without deteriorating its dielectric properties, and therefore, Ag, Cu, etc. having good conductivity can be used as a material for internal electrodes, and as a result, high frequency properties. It is possible to obtain a ceramic electronic component with good quality.

Claims

A dielectric porcelain having a main phase and a glass phase, the main phase comprising a dielectric component exhibiting dielectric properties, wherein Bi is dissolved in the dielectric component, and the main phase and / or the glass phase and a solid solution Ag in, main phase mainly composed of component represented by _{_{_{xBaO · yTiO 2 · zNd 2 O}}} 3, x is 12 ≦ x ≦ 19, y is 64 ≦ y ≦ 74, z is 9 ≦ z ≦ 19, Bi is contained in a proportion of 12～24Wt% with respect to the main component in terms _{of Bi} 2 _{O 3,} Ag 1~4wt% for the major component in the Ag ₂ O in terms is contained in an amount of, the glass phase dielectric ceramic composition characterized in that it is contained in a proportion of 5～12Wt% with respect to the main component.

2. The dielectric ceramic composition according to claim 1, wherein Pb is dissolved in the main phase.

3. The dielectric ceramic composition according to claim 1, wherein Pb is contained in a proportion of 5 wt% or less with respect to the main component of the main phase in terms of PbO.

The dielectric ceramic composition according to any one of claims 1 to 3, wherein Cu is dissolved in the glass phase.

The dielectric ceramic composition according to any one of claims 1 to 4, wherein Cu is contained in a proportion of 2 wt% or less with respect to the main component of the main phase in terms of CuO.

An element body formed by laminating a dielectric layer and an internal electrode; and an external electrode formed outside the element body and electrically connected to the internal electrode, the dielectric layer comprising a main phase and glass The main phase is composed of a dielectric component that exhibits dielectric properties, Bi is dissolved in the dielectric component, and Ag is present in the main phase and / or the glass phase. and a solid solution, main phase mainly composed of component represented by _{_{_{xBaO · yTiO 2 · zNd 2 O}}} 3, x is 12 ≦ x ≦ 19, y is 64 ≦ y ≦ 74, z is 9 ≦ z ≦ 19 a and, Bi is contained in a proportion of 12～24Wt% with respect to the main component in terms _{of Bi} 2 _{O 3,} Ag is contained in a proportion of 1～4Wt% with respect to the main component in the Ag ₂ O in terms is, ceramic the glass phase, characterized in that it is contained in a proportion of 5～12Wt% with respect to the main component Electronic components.

The ceramic electronic component according to claim 6, wherein Pb is dissolved in the main phase.

The ceramic electronic component according to claim 6 or 7, wherein Pb is contained in a proportion of 5 wt% or less with respect to the main component of the main phase in terms of PbO.

The ceramic electronic component according to claim 6, wherein Cu is dissolved in the glass phase.

10. The ceramic electronic component according to claim 6, wherein Cu is contained in a ratio of 2 wt% or less with respect to a main component of the main phase in terms of CuO.