JP4576660B2 - Conductive paste for multilayer ceramic capacitor and multilayer ceramic capacitor using the same - Google Patents
Conductive paste for multilayer ceramic capacitor and multilayer ceramic capacitor using the same Download PDFInfo
- Publication number
- JP4576660B2 JP4576660B2 JP2000089413A JP2000089413A JP4576660B2 JP 4576660 B2 JP4576660 B2 JP 4576660B2 JP 2000089413 A JP2000089413 A JP 2000089413A JP 2000089413 A JP2000089413 A JP 2000089413A JP 4576660 B2 JP4576660 B2 JP 4576660B2
- Authority
- JP
- Japan
- Prior art keywords
- glass frit
- mol
- component
- multilayer ceramic
- oxide
- 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 - Lifetime
Links
Images
Landscapes
- Ceramic Capacitors (AREA)
- Fixed Capacitors And Capacitor Manufacturing Machines (AREA)
Description
【０００１】
【発明の属する技術分野】
本発明は、積層セラミックコンデンサの外部電極形成に好適な導電性ペーストならびにこれを用いて外部電極を形成した積層セラミックコンデンサに関するものである。
【０００２】
【従来の技術】
従来より積層セラミックコンデンサは、複数のセラミック層が積層されてなるセラミック素体と、それぞれの端縁が前記セラミック層の何れかの端面に露出するように前記セラミック層間に形成された複数の内部電極と、露出した前記内部電極に電気的に接続されるように設けられた外部電極とを備えている。また、上述の外部電極は、導電性ペーストをセラミック素体の両端面に塗布し焼成して形成されている。また、このような外部電極上には、はんだ濡れ性やはんだ耐熱性の向上を目的として、Ｎｉ，Ｓｎ，はんだ等のめっき処理が施されているものがある。
【０００３】
【発明が解決しようとする課題】
しかしながら、このような従来技術によれば、上述のめっき処理を施す場合にめっき液が外部電極内に浸入し、セラミック素体のセラミック層界面に達して内部欠陥を引き起こすという問題がある。特に近年では、積層セラミックコンデンサの高容量化に伴ってセラミック層の積層数の増加や内部電極の薄層化が進み、めっき液の浸入による内部欠陥の不良が顕著となってきている。このような、めっき液の浸入による内部欠陥は、主に従来のガラスフリットの耐めっき性に起因し、具体的には、公知の３成分系ガラスであるＢ−Ｓｉ−Ｂａ−ＯガラスやＢ−Ｂａ−Ａｌ−Ｏガラス、４成分系ガラスであるＢ−Ｓｉ−Ｂａ−Ｃｕ−ＯガラスやＢ−Ｓｉ−Ｂａ−Ｎｉ−Ｏガラス等のガラスフリットが用いられていた。
【０００４】
また、内部電極を構成する導電粉末の卑金属化が進み、これに伴って外部電極を構成する導電粉末もＣｕやＮｉ等の卑金属化が進み、従来のＡｇやＡｇ／Ｐｄ等の貴金属を導電成分とする外部電極と比較して、焼成後の外部電極の焼結密度が低下する傾向があり、めっき液の浸入がより一層問題となっている。
【０００５】
本発明の目的は、上述の問題点を解消すべくなされたもので、めっき液の浸入を抑制し得る、積層セラミックコンデンサの外部電極形成用導電性ペースト、ならびにめっき液の浸入の抑制された積層セラミックコンデンサを提供することにある。
【０００６】
【課題を解決するための手段】
上記目的を達成するために、本発明の積層セラミックコンデンサ用導電性ペーストは、Ｃｕまたは／およびＮｉ成分から主になる導電粉末と、ガラスフリットと、有機ビヒクルを含有し、ガラスフリットは、Ｂ，Ｓｉ，Ｂａ，Ａｌ成分を含む主成分と、Ｃｕまたは／およびＮｉ成分からなる副成分からなる酸化物であって、実質的にＰｂ成分を含まず、Ｂａ成分を酸化物ＢａＯに換算したときの酸化物モル比は、ガラスフリット１００モル％に対して２０〜４５モル％であり、Ｓｉ成分を酸化物ＳｉＯ2に換算したときの酸化物モル比は、ガラスフリット１００モル％に対して２５〜３５モル％であることを特徴とする。
【０００７】
また、ガラスフリットの含有量は、導電粉末とガラスフリットの合計１００重量％のうち、５〜５０重量％であることを特徴とする。
【０００８】
また、本発明の積層セラミックコンデンサは、複数のセラミック層が積層されてなるセラミック素体と、それぞれの端縁がセラミック層の何れかの端面に露出するようにセラミック層間に形成された卑金属を導電成分とする複数の内部電極と、露出した内部電極に電気的に接続されるように設けられた外部電極とを備え、外部電極は、本発明の導電性ペーストがセラミック素体の両端面に塗布されて形成されていることを特徴とする。
【０００９】
【発明の実施の形態】
本発明の導電性ペーストは、５成分系または６成分系の硼珪酸バリウムアルミナ−卑金属ガラス、すなわちＢ−Ｓｉ−Ｂａ−Ａｌ−Ｃｕ−Ｏガラス、Ｂ−Ｓｉ−Ｂａ−Ａｌ−Ｎｉ−Ｏガラス、またはＢ−Ｓｉ−Ｂａ−Ａｌ−Ｃｕ−Ｎｉ−Ｏガラスを用いることにより、ガラス構造の強化が図れて耐めっき性が増し、同時に内部電極との接合安定性が増すことに特徴がある。
【００１０】
ガラスフリットを構成する成分のうち、Ｂａ成分はめっき液と安定な不溶性反応物を生成することにより耐めっき性が増す効果が得られ、ガラスフリット１００モル％中のＢａ成分の含有量は、酸化物ＢａＯ換算で２０〜４５モル％の範囲内であることを要する。含有量が２０モル％を下回ると、上述の添加効果が十分に得られない。また、含有量が４５モル％を上回ると、ガラスが低温から結晶化を引き起こし易くなるため、このようなガラスフリットを含有する導電性ペーストを用いて形成される外部電極は、焼成中に焼結阻害を引き起こしてめっき液の浸入が生じ易くなる。
【００１１】
ガラスフリットを構成する成分のうち、Ａｌ成分はガラス構造の強化を生じさせる目的で添加される。また、ＣｕやＮｉ成分は、同じ卑金属からなる内部電極との接合安定性を図る目的で添加されている。Ｂａ成分，Ａｌ成分，ＣｕもしくはＮｉ成分が、単独ではなく全３成分がＢ−Ｓｉ−Ｏ系ガラスに含まれることで、ガラス構造が強化され耐メッキ性が増す。なお、本発明のガラスフリットは上述の５成分ないし６成分ガラスに限定されることなく、さらにＬｉ，Ｎａ，Ｋ成分等のアルカリ金属酸化物や、Ｚｎ，Ｍｎ，Ｆｅ等の他の金属成分を含有していても、同様に本発明の効果が得られるが、アルカリ金属酸化物は、ガラスフリット中における構成比率が増すと内部欠陥の発生率が高くなる傾向にあるため、ガラスフリット１００重量％中のアルカリ金属酸化物は１０モル％以下であることが好ましい。
【００１２】
また、本発明の導電性ペーストにおける導電成分とガラスフリットの混合比率は、特に限定するものではないが、好ましくは導電粉末５０〜９５体積％に対してガラスフリットが５〜５０体積％である。ガラスフリットの混合比率が５体積％を下回ると、めっき液の浸入を抑制するという本発明の効果が得られにくく、他方、混合比率が５０体積％を上回ると、外部電極の表面に余剰のガラスが析出してめっき付き性が悪化する恐れがある。
【００１３】
本発明の積層セラミックコンデンサを、図１に基づいて詳細に説明する。すなわち、積層セラミックコンデンサ１は、セラミック素体２と、内部電極３，３と、外部電極４，４と、めっき膜５，５とからなる。
【００１４】
セラミック素体２は、誘電体材料、例えばＢａＴｉＯ3を主成分とするセラミックグリーンシートからなるセラミック層２ａが複数積層され、所定の温度で焼成されてなる。
【００１５】
内部電極３，３は、それぞれの端縁がセラミック層２ａの何れかの端面に露出するようにセラミック層２ａ間に形成されており、Ｃｕまたは／およびＮｉ成分を導電成分とする導電性ペーストが所定のセラミック層２ａ上に塗布され、セラミック層２ａと共に積層され、セラミック素体２と同時に焼成されてなる。
【００１６】
外部電極４，４は、セラミック素体２の両端面に本発明の導電性ペーストが塗布され焼成されてなり、セラミック素体２の端面に露出した内部電極３，３の端縁の一方と電気的・機械的に接合されている。
【００１７】
めっき膜５，５は、例えば、ＳｎやＮｉ等の無電解めっきや、はんだめっき等からなり、外部電極上４，４上に少なくとも１層形成されてなる。
【００１８】
なお、本発明の積層セラミックコンデンサのセラミック素体２の材料は、上述の実施形態に限定されることなく、例えばＰｂＴｉＯ3，ＰｂＺｒＯ3等その他の誘電体材料からなっても構わない。
【００１９】
また、本発明の積層セラミックコンデンサの内部電極の枚数は、上述の実施形態に限定されることなく、単数あるいは３枚以上の複数からなっても構わない。
【００２０】
【実施例】
（実施例１）
まず、表１に示すような組成比率となるようなガラスフリットを作製した。すなわち、まず、出発原料としてＢａＣＯ3，ＳｉＯ2，Ｈ3ＢＯ3，Ａｌ（ＯＨ）3，ＺｎＯ，ＣｕＯ，ＮｉＯを所定量調合し混合した後、アルミナるつぼで１０００〜１５００℃の範囲で溶融させ、水中に投下して急冷してガラス化させ、試料１〜２７のガラスカレットを得た。
【００２１】
次いで、試料１〜２７のガラスカレットをメノウ乳鉢で粗粉砕した後、ジルコニア球をメディアとするボールミルを用いて微粉砕を行ない、試料１〜２７のガラスフリットを得た。
【００２２】
次いで、試料１〜２７のガラスフリットを用いてＣｕを導電成分とする導電性ペーストを作製した。すなわち、Ｃｕ粉末と試料１〜２７のガラスフリットを容積比率で８０：２０の割合で混合し、テルピネオールにアクリル樹脂を２０重量％添加した有機ビヒクルを適量加え、３本ロールで混合ならびに分散させて、試料１〜２７の導電性ペーストを得た。
【００２３】
次いで、ＢａＴｉＯ3を主成分とするセラミック層を準備し、所定枚数のセラミック層の表面上に一方の端縁がセラミック層の何れかの端面側に露出するように、内部電極となるべき電極膜を印刷し、これら複数のセラミック層を所定枚数積層し圧着して、複数の生のセラミック素体を準備した。
【００２４】
次に、生のセラミック素体の両端面に、試料１〜２７の導電性ペーストを浸漬塗布し、１２０℃で１０分間乾燥させた後、中性雰囲気中で８５０℃１０分ピークの条件で焼成して、内部電極に電気的かつ機械的に接合された一対の外部電極を形成した。次に、この一対の外部電極上にＮｉめっき膜を電解めっき処理により形成し、さらにＮｉめっき膜上にＳｎめっき膜を電解めっき処理により形成して、試料１〜２７の積層セラミックコンデンサを１００００個ずつ得た。
【００２５】
そこで、試料１〜２７の積層セラミックコンデンサについて内部欠陥の発生率を測定し、これを表１にまとめた。
【００２６】
【表１】
表１から明らかであるように、導電性ペースト中に含有されるガラスフリットが、５成分のＢ−Ｓｉ−Ｂａ−Ａｌ−Ｃｕ−ＯガラスまたはＢ−Ｓｉ−Ｂａ−Ａｌ−Ｎｉ−Ｏガラスであって、Ｂａ成分を酸化物ＢａＯに換算したときの酸化物モル比が、ガラスフリット１００モル％に対して２０〜４５モル％であり、Ｓｉ成分を酸化物ＳｉＯ2に換算したときの酸化物モル比が、ガラスフリット１００モル％に対して２５〜３５モル％である試料７〜１２，１７〜１９は、内部欠陥の発生率が０〜０．０９％で低く優れ、本発明の範囲内となった。
【００２８】
また、上述の５成分に加えてアルカリ金属酸化物をガラスフリット１００モル％に対して５〜１０モル％含有してなるガラスフリットを用いた試料２１〜２７は、内部欠陥の発生率が０．０１〜０．０９％で低く優れ、本発明の範囲内となった。
【００２９】
これに対して、Ｂ成分、Ｓｉ成分、Ａｌ成分の何れかを含有しないガラスフリットを用いた試料１〜４は、内部欠陥の発生率が４．４２〜１０．２３％と高く劣り、本発明の範囲外となった。
【００３０】
また、Ｂ−Ｓｉ−Ｂａ−Ａｌ−Ｃｕ−Ｏガラスであっても、Ｂａ成分を酸化物ＢａＯに換算したときの酸化物モル比が、ガラスフリット１００モル％に対して２０モル％を下回る試料５，６は、内部欠陥の発生率がそれぞれ２．３０％，０．７６％で高く劣り、本発明の範囲外となった。
【００３１】
また、Ｂ−Ｓｉ−Ｂａ−Ａｌ−Ｃｕ−Ｏガラスであって、Ｂａ成分を酸化物ＢａＯに換算したときの酸化物モル比が、ガラスフリット１００モル％に対して４５モル％を上回る試料１３は、内部欠陥の発生率が０．２９％で高く劣り、本発明の範囲外となった。同様に、試料１４，１５は、外部電極の焼成時にガラスフリットが溶融しなかったため、積層セラミックコンデンサの外部電極形成用の導電性ペーストに用いるガラスフリットとしては不適確であり、本発明の範囲外となった。
【００３２】
また、Ｂ−Ｓｉ−Ｂａ−Ａｌ−Ｎｉ−Ｏガラスであって、Ｂａ成分を酸化物ＢａＯに換算したときの酸化物モル比が、ガラスフリット１００モル％に対して２０モル％を下回る試料１６と、４５モル％を上回る試料２０は、内部欠陥の発生率がそれぞれ０．９２％，０．１８％で高く劣り、本発明の範囲外となった。
（実施例２）
実施例１における試料１〜２７のガラスフリットと同じ組成のガラスフリットを試料２８〜５４のガラスフリットとして作製し、この試料２８〜５４のガラスフリットを用いてＮｉを導電成分とする導電性ペーストを作製した。すなわち、Ｎｉ粉末と試料２８〜５４のガラスフリットを容積比率で８０：２０の割合で混合し、テルピネオールにアクリル樹脂を２０重量％添加した有機ビヒクルを適量加え、３本ロールで混合ならびに分散させて、試料２８〜５４の導電性ペーストを得た。
【００３３】
次いで、実施例１で作製した生のセラミック素体の両端面に、試料２８〜５４の導電性ペーストを浸漬塗布し、１２０℃で１０分間乾燥させた後、中性雰囲気中で９００℃１０分ピークの条件で焼成して、内部電極に電気的かつ機械的に接合された一対の外部電極を形成した。次に、この一対の外部電極上にＮｉめっき膜を電解めっき処理により形成し、さらにＮｉめっき膜上にＳｎめっき膜を電解めっき処理により形成して、試料２８〜５４の積層セラミックコンデンサを１００００個ずつ得た。
【００３４】
そこで、試料２８〜５４の積層セラミックコンデンサについて内部欠陥の発生率を測定し、これを表２にまとめた。
【００３５】
【表２】
表２から明らかであるように、導電性ペースト中に含有されるガラスフリットが、５成分のＢ−Ｓｉ−Ｂａ−Ａｌ−Ｃｕ−ＯガラスまたはＢ−Ｓｉ−Ｂａ−Ａｌ−Ｎｉ−Ｏガラスであって、Ｂａ成分を酸化物ＢａＯに換算したときの酸化物モル比が、ガラスフリット１００モル％に対して２０〜４５モル％であり、Ｓｉ成分を酸化物ＳｉＯ2に換算したときの酸化物モル比が、ガラスフリット１００モル％に対して２５〜３５モル％である試料３４〜３９，４４〜４６は、内部欠陥の発生率が０〜０．０７％で低く優れ、本発明の範囲内となった。
【００３７】
また、上述の５成分に加えてアルカリ金属酸化物をガラスフリット１００モル％に対して５〜１０モル％含有してなるガラスフリットを用いた試料４８〜５４は、内部欠陥の発生率が０〜０．０５％で低く優れ、本発明の範囲内となった。
【００３８】
これに対して、Ｂ成分、Ｓｉ成分、Ａｌ成分の何れかを含有しないガラスフリットを用いた試料２８〜３１は、内部欠陥の発生率が１．９８〜５．６６％と高く劣り、本発明の範囲外となった。
【００３９】
また、Ｂ−Ｓｉ−Ｂａ−Ａｌ−Ｃｕ−Ｏガラスであっても、Ｂａ成分を酸化物ＢａＯに換算したときの酸化物モル比が、ガラスフリット１００モル％に対して２０モル％を下回る試料３２，３３は、内部欠陥の発生率がそれぞれ１．０５％，０．５５％で高く劣り、本発明の範囲外となった。
【００４０】
また、Ｂ−Ｓｉ−Ｂａ−Ａｌ−Ｃｕ−Ｏガラスであって、Ｂａ成分を酸化物ＢａＯに換算したときの酸化物モル比が、ガラスフリット１００モル％に対して４５モル％を上回る試料４０は、内部欠陥の発生率が０．１９％で高く劣り、本発明の範囲外となった。同様に、試料４１，４２は、外部電極の焼成時にガラスフリットが溶融しなかったため、積層セラミックコンデンサの外部電極形成用の導電性ペーストに用いるガラスフリットとしては不適確であり、本発明の範囲外となった。
【００４１】
また、Ｂ−Ｓｉ−Ｂａ−Ａｌ−Ｎｉ−Ｏガラスであって、Ｂａ成分を酸化物ＢａＯに換算したときの酸化物モル比が、ガラスフリット１００モル％に対して２０モル％を下回る試料４３と、４５モル％を上回る試料４７は、内部欠陥の発生率がそれぞれ０．８８％，０．１５％で高く劣り、本発明の範囲外となった。
（実施例３）
Ｃｕを導電粉末として、１４Ｂ−３３Ｓｉ−３３Ｂａ−７Ａｌ−８Ｃｕ−５ＮＡ−Ｏガラスからなるガラスフリットを添加した試料２２について、導電粉末とガラスフリットの構成比率を変化させた試料５７〜６２の導電性ペーストを作製した。すなわち、導電性粉末とガラスフリットの構成比率を表３に示す割合として、実施例１と同様の作製方法によって実施例５７〜６２の導電性ペーストを作製し、実施例１と同様の作製方法によって実施例５７〜６２の積層セラミックコンデンサを作製した。
【００４２】
そこで、試料５７〜６２の積層セラミックコンデンサについて内部欠陥の発生率を測定し、これを表３にまとめた。
【００４３】
【表３】
表３から明らかであるように、ガラスフリットの構成比率が、導電粉末とガラスフリットの合計１００重量％のうち５〜５０重量％である試料５８〜６１は、内部欠陥の発生率が０〜０．０９％で低く優れ、本発明の範囲内となり、かつめっき付き性も優れた。
【００４５】
【発明の効果】
以上のように本発明の導電性ペーストは、Ｃｕまたは／およびＮｉ成分から主になる導電粉末と、ガラスフリットと、有機ビヒクルを含有し、ガラスフリットは、Ｂ，Ｓｉ，Ｂａ，Ａｌ成分を含む主成分と、Ｃｕまたは／およびＮｉ成分からなる副成分からなる酸化物であって、実質的にＰｂ成分を含まず、Ｂａ成分を酸化物ＢａＯに換算したときの酸化物モル比は、ガラスフリット１００モル％に対して２０〜４５モル％であり、Ｓｉ成分を酸化物ＳｉＯ2に換算したときの酸化物モル比は、ガラスフリット１００モル％に対して２５〜３５モル％であることを特徴とすることで、耐メッキ性が向上する結果、積層セラミックコンデンサの内部欠陥不良を改善できる。
【００４６】
また、上述のガラスフリットの含有量は、導電粉末とガラスフリットの合計１００重量％のうち、５〜５０重量％であることを特徴とすることで、本発明のガラスフリットの効果が十分に発揮されて、積層セラミックコンデンサの内部欠陥不良を改善でき、かつ、十分なはんだ濡れ性を備える外部電極を形成し得る。
【００４７】
また、本発明の積層セラミックコンデンサは、複数のセラミック層が積層されてなるセラミック素体と、それぞれの端縁がセラミック層の何れかの端面に露出するようにセラミック層間に形成された卑金属を導電成分とする複数の内部電極と、露出した内部電極に電気的に接続されるように設けられた外部電極とを備え、外部電極は本発明の導電性ペーストがセラミック素体の両端面に塗布されて形成されていることを特徴とすることで、外部電極の耐メッキ性が向上する結果、内部欠陥不良が改善されるという効果が得られる。
【図面の簡単な説明】
【図１】本発明に係る一つの実施の形態の積層セラミックコンデンサの断面図である。
【符号の説明】
１ 積層セラミックコンデンサ
２ セラミック素体
３ 内部電極
４ 外部電極
５，６ めっき膜[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a conductive paste suitable for forming an external electrode of a multilayer ceramic capacitor and a multilayer ceramic capacitor in which an external electrode is formed using the conductive paste.
[0002]
[Prior art]
Conventionally, a multilayer ceramic capacitor has a ceramic body in which a plurality of ceramic layers are laminated, and a plurality of internal electrodes formed between the ceramic layers so that each edge is exposed at one of the end faces of the ceramic layer. And an external electrode provided so as to be electrically connected to the exposed internal electrode. Further, the external electrode described above is formed by applying a conductive paste to both end faces of the ceramic body and firing it. Some external electrodes are plated with Ni, Sn, solder, etc. for the purpose of improving solder wettability and solder heat resistance.
[0003]
[Problems to be solved by the invention]
However, according to such a conventional technique, there is a problem that when the above-described plating treatment is performed, the plating solution enters the external electrode and reaches the ceramic layer interface of the ceramic body to cause internal defects. Particularly in recent years, with the increase in capacity of multilayer ceramic capacitors, the number of laminated ceramic layers and the thickness of internal electrodes have progressed, and defects in internal defects due to penetration of the plating solution have become prominent. Such internal defects due to the penetration of the plating solution are mainly caused by the plating resistance of the conventional glass frit. Specifically, B-Si-Ba-O glass, which is a known ternary glass, or B Glass frit such as —Ba—Al—O glass, B—Si—Ba—Cu—O glass and B—Si—Ba—Ni—O glass, which are quaternary glasses, has been used.
[0004]
In addition, the base metal of the conductive powder constituting the internal electrode has progressed, and with this, the base powder of the conductive powder constituting the external electrode has also progressed to base metal such as Cu and Ni, and the conventional noble metals such as Ag and Ag / Pd are used as conductive components. Compared with the external electrode, the sintered density of the external electrode after firing tends to be reduced, and the infiltration of the plating solution becomes more problematic.
[0005]
An object of the present invention is to solve the above-mentioned problems, and can suppress the intrusion of a plating solution, and can provide a conductive paste for forming an external electrode of a multilayer ceramic capacitor, and a laminated layer in which the infiltration of a plating solution is suppressed. It is to provide a ceramic capacitor.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the conductive paste for a multilayer ceramic capacitor of the present invention contains a conductive powder mainly composed of Cu or / and Ni, glass frit, and an organic vehicle. An oxide composed of a main component containing Si, Ba, and Al components and a subcomponent composed of Cu or / and Ni components, substantially not including a Pb component, and when the Ba component is converted to oxide BaO The oxide molar ratio is 20 to 45 mol% with respect to 100 mol% of the glass frit, and the oxide molar ratio when the Si component is converted to oxide SiO 2 is 25 to 25 mol with respect to 100 mol% of the glass frit. It is characterized by being 35 mol%.
[0007]
The content of the glass frit is 5 to 50% by weight in a total of 100% by weight of the conductive powder and the glass frit.
[0008]
In addition, the multilayer ceramic capacitor of the present invention electrically conducts a ceramic body formed by laminating a plurality of ceramic layers and a base metal formed between the ceramic layers so that each edge is exposed to one end face of the ceramic layer. A plurality of internal electrodes as components, and external electrodes provided so as to be electrically connected to the exposed internal electrodes, and the external electrodes are coated with the conductive paste of the present invention on both end faces of the ceramic body It is characterized by being formed.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
The conductive paste of the present invention is a five-component or six-component borosilicate barium alumina-base metal glass, that is, B-Si-Ba-Al-Cu-O glass, B-Si-Ba-Al-Ni-O glass. In addition, by using B—Si—Ba—Al—Cu—Ni—O glass, the glass structure is strengthened and the plating resistance is increased, and at the same time, the bonding stability with the internal electrode is increased.
[0010]
Among the components constituting the glass frit, the Ba component has an effect of increasing the plating resistance by generating a stable insoluble reactant with the plating solution. The content of the Ba component in 100 mol% of the glass frit is determined by oxidation. It needs to be in the range of 20 to 45 mol% in terms of product BaO. When the content is less than 20 mol%, the above-described addition effect cannot be obtained sufficiently. Further, if the content exceeds 45 mol%, the glass tends to cause crystallization from a low temperature. Therefore, an external electrode formed using a conductive paste containing such a glass frit is sintered during firing. Inhibition causes the plating solution to easily enter.
[0011]
Of the components constituting the glass frit, the Al component is added for the purpose of strengthening the glass structure. Further, Cu and Ni components are added for the purpose of bonding stability with an internal electrode made of the same base metal. The Ba component, Al component, Cu or Ni component is not alone, but all three components are contained in the B—Si—O-based glass, whereby the glass structure is strengthened and the plating resistance is increased. The glass frit of the present invention is not limited to the above-mentioned 5-component or 6-component glass, and further contains an alkali metal oxide such as Li, Na, K component, and other metal components such as Zn, Mn, Fe. Even if it is contained, the effect of the present invention can be obtained in the same manner. However, since the alkali metal oxide tends to increase the rate of occurrence of internal defects when the composition ratio in the glass frit is increased, the glass frit is 100% by weight. It is preferable that the alkali metal oxide in it is 10 mol% or less.
[0012]
Further, the mixing ratio of the conductive component and the glass frit in the conductive paste of the present invention is not particularly limited, but the glass frit is preferably 5 to 50% by volume with respect to 50 to 95% by volume of the conductive powder. If the mixing ratio of the glass frit is less than 5% by volume, it is difficult to obtain the effect of the present invention that suppresses the penetration of the plating solution. On the other hand, if the mixing ratio exceeds 50% by volume, excess glass is formed on the surface of the external electrode. May precipitate and the plating property may deteriorate.
[0013]
The multilayer ceramic capacitor of the present invention will be described in detail with reference to FIG. That is, the multilayer ceramic capacitor 1 includes a
[0014]
The
[0015]
The
[0016]
The
[0017]
The plated
[0018]
The material of the
[0019]
The number of internal electrodes of the multilayer ceramic capacitor of the present invention is not limited to the above-described embodiment, and may be a single number or a plurality of three or more.
[0020]
【Example】
Example 1
First, a glass frit having a composition ratio as shown in Table 1 was prepared. That is, first, BaCO 3 , SiO 2 , H 3 BO 3 , Al (OH) 3 , ZnO, CuO, and NiO as starting materials are prepared and mixed in a predetermined amount, and then melted in a range of 1000 to 1500 ° C. with an alumina crucible. Then, it was dropped into water and rapidly cooled to vitrify to obtain glass cullet of Samples 1 to 27.
[0021]
Next, the glass cullet of samples 1 to 27 was coarsely pulverized in an agate mortar, and then finely pulverized using a ball mill using zirconia spheres as media, to obtain glass frit of samples 1 to 27.
[0022]
Next, a conductive paste containing Cu as a conductive component was prepared using the glass frit of Samples 1 to 27. That is, Cu powder and the glass frits of Samples 1 to 27 were mixed at a volume ratio of 80:20, an appropriate amount of an organic vehicle in which 20% by weight of acrylic resin was added to terpineol was added, and mixed and dispersed with three rolls. Samples 1 to 27 were obtained.
[0023]
Next, a ceramic layer mainly composed of BaTiO 3 is prepared, and an electrode film to be an internal electrode is formed so that one end edge is exposed on any end face side of the ceramic layer on the surface of a predetermined number of ceramic layers. A plurality of ceramic layers were laminated and pressure-bonded to prepare a plurality of raw ceramic bodies.
[0024]
Next, the conductive paste of Samples 1 to 27 is dip-coated on both end faces of the raw ceramic body, dried at 120 ° C. for 10 minutes, and then fired at 850 ° C. for 10 minutes in a neutral atmosphere. Thus, a pair of external electrodes joined electrically and mechanically to the internal electrodes was formed. Next, an Ni plating film is formed on the pair of external electrodes by electrolytic plating, and an Sn plating film is further formed on the Ni plating film by electrolytic plating. Thus, 10,000 multilayer ceramic capacitors of Samples 1 to 27 are formed. I got one by one.
[0025]
Therefore, the incidence rate of internal defects was measured for the multilayer ceramic capacitors of Samples 1 to 27, and these are summarized in Table 1.
[0026]
[Table 1]
As is apparent from Table 1, the glass frit contained in the conductive paste is a five-component B-Si-Ba-Al-Cu-O glass or B-Si-Ba-Al-Ni-O glass. there are, oxide molar ratio when converted to Ba component oxide BaO is a 20 to 45 mol% with respect to the glass frit 100 mol%, oxide when converted to Si components in the oxide SiO 2 Samples 7 to 12 and 17 to 19 having a molar ratio of 25 to 35 mol% with respect to 100 mol% of the glass frit have excellent internal defect generation rates of 0 to 0.09%, which are excellent and within the scope of the present invention. It became.
[0028]
Samples 21 to 27 using a glass frit containing 5 to 10 mol% of an alkali metal oxide in addition to the above five components with respect to 100 mol% of the glass frit have an internal defect occurrence rate of 0. It was low and excellent at 01 to 0.09%, and was within the scope of the present invention.
[0029]
On the other hand, Samples 1 to 4 using glass frit that does not contain any of the B component, the Si component, and the Al component have a high internal defect generation rate of 4.42 to 10.23%, which is inferior. It was out of range.
[0030]
Moreover, even if it is B-Si-Ba-Al-Cu-O glass, the sample whose oxide molar ratio when converting Ba component into oxide BaO is less than 20 mol% with respect to 100 mol% of glass frit Nos. 5 and 6 were high and inferior at 2.30% and 0.76%, respectively, and were outside the scope of the present invention.
[0031]
Moreover, it is B-Si-Ba-Al-Cu-O glass, Comprising: The sample 13 in which the oxide molar ratio when converting a Ba component into oxide BaO exceeds 45 mol% with respect to 100 mol% of glass frit The internal defect occurrence rate was 0.29%, which was high and inferior, and was outside the scope of the present invention. Similarly, the samples 14 and 15 were not suitable as glass frit used for the conductive paste for forming the external electrode of the multilayer ceramic capacitor because the glass frit was not melted when the external electrode was fired, and are outside the scope of the present invention. It became.
[0032]
Moreover, it is B-Si-Ba-Al-Ni-O glass, Comprising: The sample 16 in which an oxide molar ratio when Ba component is converted into oxide BaO is less than 20 mol% with respect to 100 mol% of glass frit In
(Example 2)
A glass frit having the same composition as the glass frit of samples 1 to 27 in Example 1 was produced as a glass frit of samples 28 to 54, and a conductive paste containing Ni as a conductive component was produced using the glass frit of samples 28 to 54. Produced. That is, Ni powder and glass frit of samples 28 to 54 are mixed at a volume ratio of 80:20, an appropriate amount of an organic vehicle in which 20% by weight of acrylic resin is added to terpineol is added, and mixed and dispersed by three rolls. Thus, conductive pastes of samples 28 to 54 were obtained.
[0033]
Next, the conductive paste of Samples 28 to 54 was dip-coated on both end faces of the raw ceramic body produced in Example 1, dried at 120 ° C. for 10 minutes, and then 900 ° C. for 10 minutes in a neutral atmosphere. Firing was performed under peak conditions to form a pair of external electrodes electrically and mechanically joined to the internal electrodes. Next, an Ni plating film is formed on the pair of external electrodes by electrolytic plating treatment, and an Sn plating film is formed on the Ni plating film by electrolytic plating treatment, so that 10,000 multilayer ceramic capacitors of samples 28 to 54 are obtained. I got one by one.
[0034]
Therefore, the incidence rate of internal defects was measured for the multilayer ceramic capacitors of Samples 28 to 54, and these are summarized in Table 2.
[0035]
[Table 2]
As apparent from Table 2, the glass frit contained in the conductive paste is a five-component B-Si-Ba-Al-Cu-O glass or B-Si-Ba-Al-Ni-O glass. there are, oxide molar ratio when converted to Ba component oxide BaO is a 20 to 45 mol% with respect to the glass frit 100 mol%, oxide when converted to Si components in the oxide SiO 2 Samples 34 to 39 and 44 to 46 having a molar ratio of 25 to 35 mol% with respect to 100 mol% of the glass frit have a low internal defect occurrence rate of 0 to 0.07%, and are excellent. It became.
[0037]
Samples 48 to 54 using a glass frit containing 5 to 10 mol% of an alkali metal oxide in addition to the above five components with respect to 100 mol% of the glass frit have an internal defect occurrence rate of 0 to 0. It was low and excellent at 0.05%, and was within the scope of the present invention.
[0038]
On the other hand, samples 28 to 31 using glass frit containing no B component, Si component, or Al component have a high internal defect generation rate of 1.98 to 5.66%, which is inferior. It was out of range.
[0039]
Moreover, even if it is B-Si-Ba-Al-Cu-O glass, the sample whose oxide molar ratio when converting Ba component into oxide BaO is less than 20 mol% with respect to 100 mol% of glass frit Nos. 32 and 33 were high and inferior at 1.05% and 0.55%, respectively, and were outside the scope of the present invention.
[0040]
Moreover, it is B-Si-Ba-Al-Cu-O glass, Comprising: The sample 40 in which an oxide molar ratio when converting Ba component into oxide BaO exceeds 45 mol% with respect to 100 mol% of glass frit The occurrence rate of internal defects was as high as 0.19%, which was out of the scope of the present invention. Similarly, since the glass frit did not melt during firing of the external electrodes, the samples 41 and 42 are unsuitable as glass frit used for the conductive paste for forming the external electrodes of the multilayer ceramic capacitor, and are outside the scope of the present invention. It became.
[0041]
Further, the sample 43 is a B-Si-Ba-Al-Ni-O glass, and the oxide molar ratio when the Ba component is converted to the oxide BaO is less than 20 mol% with respect to 100 mol% of the glass frit. In the sample 47 exceeding 45 mol%, the internal defect occurrence rates were 0.88% and 0.15%, respectively, which were high and inferior, and were outside the scope of the present invention.
(Example 3)
Conductivity of Samples 57 to 62 in which the composition ratio of the conductive powder and the glass frit was changed with respect to Sample 22 to which glass frit made of 14B-33Si-33Ba-7Al-8Cu-5NA-O glass was added using Cu as the conductive powder. A paste was prepared. That is, the conductive pastes of Examples 57 to 62 were prepared by the same manufacturing method as in Example 1 with the constituent ratio of the conductive powder and glass frit shown in Table 3, and the same manufacturing method as in Example 1 was used. Multilayer ceramic capacitors of Examples 57 to 62 were produced.
[0042]
Therefore, the occurrence rate of internal defects was measured for the multilayer ceramic capacitors of Samples 57 to 62, and these are summarized in Table 3.
[0043]
[Table 3]
As is apparent from Table 3, samples 58 to 61 in which the composition ratio of the glass frit is 5 to 50% by weight out of the total 100% by weight of the conductive powder and the glass frit have an internal defect occurrence rate of 0 to 0. 0.09%, which is low and excellent, is within the scope of the present invention, and has excellent plating properties.
[0045]
【The invention's effect】
As described above, the conductive paste of the present invention contains a conductive powder mainly composed of Cu or / and Ni, glass frit, and an organic vehicle, and the glass frit contains B, Si, Ba, and Al components. An oxide composed of a main component and subcomponents composed of Cu and / or Ni, substantially not including a Pb component, and an oxide molar ratio when the Ba component is converted to an oxide BaO is a glass frit. and 20 to 45 mol% relative to 100 mol%, the oxide molar ratio when converted to Si components in oxide SiO 2 is characterized by a 35 mol% 25 to the glass frit 100 mol% As a result of improving the plating resistance, the internal defect defect of the multilayer ceramic capacitor can be improved.
[0046]
Further, the content of the glass frit described above is 5 to 50% by weight out of 100% by weight of the total of the conductive powder and the glass frit, so that the effect of the glass frit of the present invention is sufficiently exhibited. Thus, the internal defect defect of the multilayer ceramic capacitor can be improved and an external electrode having sufficient solder wettability can be formed.
[0047]
In addition, the multilayer ceramic capacitor of the present invention electrically conducts a ceramic body formed by laminating a plurality of ceramic layers and a base metal formed between the ceramic layers so that each edge is exposed to one end face of the ceramic layer. A plurality of internal electrodes as components, and external electrodes provided so as to be electrically connected to the exposed internal electrodes. The external electrodes are coated with the conductive paste of the present invention on both end faces of the ceramic body. As a result, the plating resistance of the external electrode is improved, and as a result, an internal defect defect is improved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a multilayer ceramic capacitor according to an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Multilayer
Claims (3)
前記ガラスフリットは、Ｂ，Ｓｉ，Ｂａ，Ａｌ成分を含む主成分と、Ｃｕまたは／およびＮｉ成分からなる副成分からなる酸化物であって、実質的にＰｂ成分を含まず、
前記Ｂａ成分を酸化物ＢａＯに換算したときの酸化物モル比は、前記ガラスフリット１００モル％に対して２０〜４５モル％であり、
前記Ｓｉ成分を酸化物ＳｉＯ2に換算したときの酸化物モル比は、前記ガラスフリット１００モル％に対して２５〜３５モル％であることを特徴とする、積層セラミックコンデンサ用導電性ペースト。Containing conductive powder mainly composed of Cu or / and Ni component, glass frit and organic vehicle,
The glass frit is an oxide composed of a main component including B, Si, Ba, and Al components and a subcomponent composed of Cu or / and Ni components, and substantially does not include a Pb component.
The oxide molar ratio when the Ba component is converted to the oxide BaO is 20 to 45 mol% with respect to 100 mol% of the glass frit,
The conductive paste for multilayer ceramic capacitors, wherein an oxide molar ratio when the Si component is converted to oxide SiO 2 is 25 to 35 mol% with respect to 100 mol% of the glass frit.
前記外部電極は、請求項１または２に記載の導電性ペーストが前記セラミック素体の両端面に塗布されて形成されていることを特徴とする、積層セラミックコンデンサ。A ceramic body formed by laminating a plurality of ceramic layers; and a plurality of internal electrodes having a base metal formed between the ceramic layers as conductive components so that each edge is exposed at any end face of the ceramic layer; An external electrode provided so as to be electrically connected to the exposed internal electrode,
3. The multilayer ceramic capacitor according to claim 1, wherein the external electrode is formed by applying the conductive paste according to claim 1 or 2 to both end faces of the ceramic body.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000089413A JP4576660B2 (en) | 2000-03-28 | 2000-03-28 | Conductive paste for multilayer ceramic capacitor and multilayer ceramic capacitor using the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2000089413A JP4576660B2 (en) | 2000-03-28 | 2000-03-28 | Conductive paste for multilayer ceramic capacitor and multilayer ceramic capacitor using the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2001274035A JP2001274035A (en) | 2001-10-05 |
| JP4576660B2 true JP4576660B2 (en) | 2010-11-10 |
Family
ID=18605180
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2000089413A Expired - Lifetime JP4576660B2 (en) | 2000-03-28 | 2000-03-28 | Conductive paste for multilayer ceramic capacitor and multilayer ceramic capacitor using the same |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP4576660B2 (en) |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101532114B1 (en) * | 2011-11-11 | 2015-06-29 | 삼성전기주식회사 | Multi-layered ceramic electronic parts |
| WO2013108533A1 (en) * | 2012-01-19 | 2013-07-25 | 株式会社村田製作所 | Ceramic electronic component |
| JP5904305B2 (en) | 2013-04-25 | 2016-04-13 | 株式会社村田製作所 | Multilayer ceramic capacitor and manufacturing method thereof |
| KR20170096462A (en) * | 2016-02-16 | 2017-08-24 | 삼성전기주식회사 | Multilayer capacitor and manufacturing method of the same |
| JP6570478B2 (en) | 2016-05-31 | 2019-09-04 | 太陽誘電株式会社 | Multilayer ceramic capacitor and manufacturing method thereof |
Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6077187A (en) * | 1983-10-04 | 1985-05-01 | 日本碍子株式会社 | Ceramic electronic part and manufacture |
| JPS61274397A (en) * | 1985-05-30 | 1986-12-04 | 株式会社住友金属セラミックス | Low temperature baked ceramic substrate and manufacture thereof |
| JPH0239410A (en) * | 1988-07-28 | 1990-02-08 | Shoei Chem Ind Co | Conductive composed material for ceramic capacitor terminal electrode |
| JPH03208831A (en) * | 1990-01-08 | 1991-09-12 | Murata Mfg Co Ltd | Electrically conductive paste |
| JPH0946013A (en) * | 1995-05-19 | 1997-02-14 | Nikko Co | Through-hole filling conductive paste and ceramic circuit board |
| JPH1021744A (en) * | 1996-06-28 | 1998-01-23 | Mitsuboshi Belting Ltd | Copper conductor paste and substrate printed therewith |
| JPH10188671A (en) * | 1996-10-29 | 1998-07-21 | Mitsuboshi Belting Ltd | Copper conductive paste and board printed therewith |
| JPH10294017A (en) * | 1997-04-21 | 1998-11-04 | Murata Mfg Co Ltd | Conductive paste |
| JPH11260146A (en) * | 1998-03-12 | 1999-09-24 | Murata Mfg Co Ltd | Conductive paste and electronic component |
| JP2002025337A (en) * | 2000-07-10 | 2002-01-25 | Tdk Corp | Conductive paste, outer electrode and manufacturing method of the same |
-
2000
- 2000-03-28 JP JP2000089413A patent/JP4576660B2/en not_active Expired - Lifetime
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6077187A (en) * | 1983-10-04 | 1985-05-01 | 日本碍子株式会社 | Ceramic electronic part and manufacture |
| JPS61274397A (en) * | 1985-05-30 | 1986-12-04 | 株式会社住友金属セラミックス | Low temperature baked ceramic substrate and manufacture thereof |
| JPH0239410A (en) * | 1988-07-28 | 1990-02-08 | Shoei Chem Ind Co | Conductive composed material for ceramic capacitor terminal electrode |
| JPH03208831A (en) * | 1990-01-08 | 1991-09-12 | Murata Mfg Co Ltd | Electrically conductive paste |
| JPH0946013A (en) * | 1995-05-19 | 1997-02-14 | Nikko Co | Through-hole filling conductive paste and ceramic circuit board |
| JPH1021744A (en) * | 1996-06-28 | 1998-01-23 | Mitsuboshi Belting Ltd | Copper conductor paste and substrate printed therewith |
| JPH10188671A (en) * | 1996-10-29 | 1998-07-21 | Mitsuboshi Belting Ltd | Copper conductive paste and board printed therewith |
| JPH10294017A (en) * | 1997-04-21 | 1998-11-04 | Murata Mfg Co Ltd | Conductive paste |
| JPH11260146A (en) * | 1998-03-12 | 1999-09-24 | Murata Mfg Co Ltd | Conductive paste and electronic component |
| JP2002025337A (en) * | 2000-07-10 | 2002-01-25 | Tdk Corp | Conductive paste, outer electrode and manufacturing method of the same |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2001274035A (en) | 2001-10-05 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US6982864B1 (en) | Copper termination inks containing lead free and cadmium free glasses for capacitors | |
| US7339780B2 (en) | Copper termination inks containing lead free and cadmium free glasses for capacitors | |
| JP2711618B2 (en) | Dielectric composition, multilayer wiring board and multilayer ceramic capacitor | |
| TWI704118B (en) | Conductive paste and method for forming terminal electrode of multilayer ceramic part | |
| JP5003683B2 (en) | Glass ceramic composition, glass ceramic sintered body, and multilayer ceramic electronic component | |
| JP5040918B2 (en) | Glass ceramic composition, glass ceramic sintered body, and multilayer ceramic electronic component | |
| WO2006003755A1 (en) | Electroconductive paste and ceramic electronic parts using the same | |
| KR100433950B1 (en) | Conductive paste and ceramic electronic component | |
| JP3799933B2 (en) | Conductive paste and ceramic electronic components | |
| JP3988533B2 (en) | Glass-ceramic composition, glass-ceramic, and ceramic multilayer substrate | |
| JPH0222806A (en) | Laminated ceramic capacitor | |
| US6936558B2 (en) | Low temperature sinterable dielectric ceramic composition, multilayer ceramic chip capacitor and ceramic electronic device | |
| JP4576660B2 (en) | Conductive paste for multilayer ceramic capacitor and multilayer ceramic capacitor using the same | |
| JP2001284160A (en) | Conductive paste and laminated ceramic electronic component using the same | |
| JP2005228904A (en) | Multilayer ceramic capacitoar | |
| KR100664979B1 (en) | Glass frit and procee for the same, paste composition for external electrode and multilayer ceramic chip capacitor using the same | |
| JP4590666B2 (en) | Conductive paste and ceramic electronic component using the same | |
| JP3337819B2 (en) | Dielectric composition, multilayer wiring board and multilayer ceramic capacitor | |
| JPH11102835A (en) | Laminated ceramic electronic component and manufacture thereof | |
| JP2005019185A (en) | Copper conductive paste and laminated ceramic electronic part | |
| JP2003323817A (en) | Conductive paste and laminated ceramic electronic part | |
| JPH0786079A (en) | Chip capacitor for high frequency | |
| JP4702021B2 (en) | Ceramic substrate with conductor layer and method for producing the same | |
| JPH06176956A (en) | Laminated porcelain capacitor | |
| JPH09120710A (en) | Conductive composition and ceramic capacitor using same |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20061115 |
|
| A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20090501 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20090602 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20090908 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20091105 |
|
| A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20100105 |
|
| A521 | Written amendment |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20100225 |
|
| 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: 20100727 |
|
| A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 |
|
| A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20100809 |
|
| FPAY | Renewal fee payment (event date is renewal date of database) |
Free format text: PAYMENT UNTIL: 20130903 Year of fee payment: 3 |
|
| R150 | Certificate of patent or registration of utility model |
Ref document number: 4576660 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R150 Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
| EXPY | Cancellation because of completion of term |