JP2004196565A - Dielectric ceramic, its manufacturing method, and multilayer ceramic capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dielectric ceramic having excellent reliability, which is manufactured by firing under a reducing atmosphere, and characterized in that change of the dielectric constant with temperature is small, secular change of the capacitance under the condition in which a DC voltage is applied is small, the CR (capacitance insulation-resistance) product is high, and the accelerated life of the insulation resistance at an elevated temperature and high voltage is long enough when it is used for constituting a multilayer ceramic capacitor. <P>SOLUTION: The dielectric ceramic has a composition comprising a main component expressed by ABO<SB>3</SB>(wherein, A is Ba or the like; and B is Ti or the like) and additive components R (La or the like) and M (Mn or the like), and is composed of crystal particles 21 of the main component expressed by ABO<SB>3</SB>and crystal grain boundary 22. The dielectric ceramic satisfies following condition: C<SB>R</SB>/C<SB>M</SB>>1 (wherein, C<SB>R</SB>is the concentration of R; and C<SB>M</SB>is the concentration of M) in 60% or more of respective analysis points of analysis points 23 each located in the area close to the surface of each crystal particle 21 and of analysis points 24 each located in the crystal grain boundary 22. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【００７３】
【表２】

【００７４】
表１および表２において、焼結助剤を除いて、各成分の係数はモル比を示している。焼結助剤については、ＡＢＯ₃ １００重量部に対する重量部で示している。
【００７５】
（実施例１）
主成分としてのＡＢＯ₃ において、Ａを含む化合物として、ＢａＣＯ₃ およびＳｒＣＯ₃ を用意し、Ｂを含む化合物として、ＴｉＯ₂ を用意した。次いで、これらの粉末を、表１の「ＡＢＯ₃ 」の欄に示した組成比となるように秤量し、純水を加えてボールミルにより２４時間湿式混合した後、蒸発乾燥した。次いで、この混合粉末を、自然雰囲気中において、１１００℃の温度で仮焼してＡＢＯ₃ を合成し、粉砕することによって、実施例１に係るＡＢＯ₃ 粉末を得た。
【００７６】
他方、添加成分として、Ｈｏ₂ Ｏ₃ およびＭｎＯ₂ を用意し、これらの粉末を、表１の「Ｒ成分」および「Ｍ成分」の各欄に示した組成比となるように秤量し、ボールミルにより湿式混合した後、１０００℃の温度で仮焼し、次いで粉砕することによって、実施例１に係る仮焼粉末を得た。
【００７７】
次に、上述のＡＢＯ₃ 粉末と仮焼粉末の一部とを、表１に示した「ＡＢＯ₃ 」および「仮焼粉末の一部」の各欄に示した組成比となるように秤量し、純水を加えてボールミルにより２４時間湿式混合した後、蒸発乾燥した。次いで、この混合粉末を、自然雰囲気中において、９００℃の温度で仮焼し、粉砕することによって、実施例１に係る変性ＡＢＯ₃ 粉末を得た。
【００７８】
次に、上述の変性ＡＢＯ₃ 粉末に、表１の「仮焼粉末の残部」の欄に示した組成比となるように、前述の仮焼粉末の残部を配合するとともに、表１の「その他」および「焼結助剤」の各欄に示した組成比となるように、ＭｇＯおよびＢａＣＯ₃ ならびにＢ₂ Ｏ₃ −Ｌｉ₂ Ｏ−ＳｉＯ₂ −ＢａＯ系の焼結助剤を配合し、実施例１に係る誘電体セラミック原料粉末を得た。
【００７９】
（実施例２）
主成分としてのＡＢＯ₃ において、Ａを含む化合物として、ＢａＣＯ₃ およびＣａＣＯ₃ を用意し、Ｂを含む化合物として、ＴｉＯ₂ およびＨｆＯ₂ を用意した。次いで、これらの粉末を、表１の「ＡＢＯ₃ 」の欄に示した組成比となるように秤量し、純水を加えてボールミルにより２４時間湿式混合した後、蒸発乾燥した。次いで、この混合粉末を、自然雰囲気中において、１１００℃の温度で仮焼してＡＢＯ₃ を合成し、粉砕することによって、実施例２に係るＡＢＯ₃ 粉末を得た。
【００８０】
他方、添加成分として、Ｓｍ₂ Ｏ₃ 、Ｙ₂ Ｏ₃ 、ＭｎＯ₂ およびＣｒ₂ Ｏ₃ を用意し、これらの粉末を、表１の「Ｒ成分」および「Ｍ成分」の各欄に示した組成比となるように秤量し、ボールミルにより湿式混合した後、１０００℃の温度で仮焼し、次いで粉砕することによって、実施例２に係る仮焼粉末を得た。
【００８１】
次に、上述のＡＢＯ₃ 粉末と仮焼粉末の一部とを、表１に示した「ＡＢＯ₃ 」および「仮焼粉末の一部」の各欄に示した組成比となるように秤量し、純水を加えてボールミルにより２４時間湿式混合した後、蒸発乾燥した。次いで、この混合粉末を、自然雰囲気中において、９００℃の温度で仮焼し、粉砕することによって、実施例２に係る変性ＡＢＯ₃ 粉末を得た。
【００８２】
次に、上述の変性ＡＢＯ₃ 粉末に、表１の「仮焼粉末の残部」の欄に示した組成比となるように、前述の仮焼粉末の残部を配合するとともに、表１の「その他」および「焼結助剤」の各欄に示した組成比となるように、ＢａＣＯ₃ および実施例１の場合と同様の組成の焼結助剤を配合し、実施例２に係る誘電体セラミック原料粉末を得た。
【００８３】
（実施例３）
主成分としてのＡＢＯ₃ において、Ａを含む化合物として、ＢａＣＯ₃ およびＣａＣＯ₃ を用意し、Ｂを含む化合物として、ＴｉＯ₂ およびＺｒＯ₂ を用意した。次いで、これらの粉末を、表１の「ＡＢＯ₃ 」の欄に示した組成比となるように秤量し、純水を加えてボールミルにより２４時間湿式混合した後、蒸発乾燥した。次いで、この混合粉末を、自然雰囲気中において、１１００℃の温度で仮焼してＡＢＯ₃ を合成し、粉砕することによって、実施例３に係るＡＢＯ₃ 粉末を得た。
【００８４】
他方、添加成分として、Ｅｒ₂ Ｏ₃ およびＣｏＯ₃ を用意し、これらの粉末を、表１の「Ｒ成分」および「Ｍ成分」の各欄に示した組成比となるように秤量し、ボールミルにより湿式混合した後、１０００℃の温度で仮焼し、次いで粉砕することによって、実施例３に係る仮焼粉末を得た。
【００８５】
次に、上述のＡＢＯ₃ 粉末と仮焼粉末の一部とを、表１に示した「ＡＢＯ₃ 」および「仮焼粉末の一部」の各欄に示した組成比となるように秤量し、純水を加えてボールミルにより２４時間湿式混合した後、蒸発乾燥した。次いで、この混合粉末を、自然雰囲気中において、９００℃の温度で仮焼し、粉砕することによって、実施例３に係る変性ＡＢＯ₃ 粉末を得た。
【００８６】
次に、上述の変性ＡＢＯ₃ 粉末に、表１の「仮焼粉末の残部」の欄に示した組成比となるように、前述の仮焼粉末の残部を配合するとともに、表１の「その他」および「焼結助剤」の各欄に示した組成比となるように、Ａｌ₂ Ｏ₃ およびＢａＣＯ₃ ならびに実施例１の場合と同様の組成の焼結助剤を配合し、実施例３に係る誘電体セラミック原料粉末を得た。
【００８７】
（実施例４）
主成分としてのＡＢＯ₃ において、Ａを含む化合物として、ＢａＣＯ₃ およびＣａＣＯ₃ を用意し、Ｂを含む化合物として、ＴｉＯ₂ を用意した。次いで、これらの粉末を、表１の「ＡＢＯ₃ 」の欄に示した組成比となるように秤量し、純水を加えてボールミルにより２４時間湿式混合した後、蒸発乾燥した。次いで、この混合粉末を、自然雰囲気中において、１１００℃の温度で仮焼してＡＢＯ₃ を合成し、粉砕することによって、実施例４に係るＡＢＯ₃ 粉末を得た。
【００８８】
他方、添加成分として、Ｌａ₂ Ｏ₃ 、Ｄｙ₂ Ｏ₃ およびＣｒ₂ Ｏ₃ を用意し、これらの粉末を、表１の「Ｒ成分」および「Ｍ成分」の各欄に示した組成比となるように秤量し、ボールミルにより湿式混合した後、１０００℃の温度で仮焼し、次いで粉砕することによって、実施例４に係る仮焼粉末を得た。
【００８９】
次に、上述のＡＢＯ₃ 粉末と仮焼粉末の一部とを、表１に示した「ＡＢＯ₃ 」および「仮焼粉末の一部」の各欄に示した組成比となるように秤量し、純水を加えてボールミルにより２４時間湿式混合した後、蒸発乾燥した。次いで、この混合粉末を、自然雰囲気中において、９００℃の温度で仮焼し、粉砕することによって、実施例４に係る変性ＡＢＯ₃ 粉末を得た。
【００９０】
次に、上述の変性ＡＢＯ₃ 粉末に、表１の「仮焼粉末の残部」の欄に示した組成比となるように、前述の仮焼粉末の残部を配合するとともに、表１の「その他」および「焼結助剤」の各欄に示した組成比となるように、Ｃｒ₂ Ｏ₃ およびＢａＣＯ₃ ならびに実施例１の場合と同様の組成の焼結助剤を配合し、実施例４に係る誘電体セラミック原料粉末を得た。
【００９１】
（実施例５）
主成分としてのＡＢＯ₃ において、Ａを含む化合物として、ＢａＣＯ₃ を用意し、Ｂを含む化合物として、ＴｉＯ₂ を用意した。次いで、これらの粉末を、表１の「ＡＢＯ₃ 」の欄に示した組成比となるように秤量し、純水を加えてボールミルにより２４時間湿式混合した後、蒸発乾燥した。次いで、この混合粉末を、自然雰囲気中において、１１００℃の温度で仮焼してＡＢＯ₃ を合成し、粉砕することによって、実施例５に係るＡＢＯ₃ 粉末を得た。
【００９２】
他方、添加成分として、Ｄｙ₂ Ｏ₃ 、ＭｎＯ₂ およびＣｒ₂ Ｏ₃ を用意し、これらの粉末を、表１の「Ｒ成分」および「Ｍ成分」の各欄に示した組成比となるように秤量し、ボールミルにより湿式混合した後、１０００℃の温度で仮焼し、次いで粉砕することによって、実施例５に係る仮焼粉末を得た。
【００９３】
次に、上述のＡＢＯ₃ 粉末と仮焼粉末の一部とを、表１に示した「ＡＢＯ₃ 」および「仮焼粉末の一部」の各欄に示した組成比となるように秤量し、純水を加えてボールミルにより２４時間湿式混合した後、蒸発乾燥した。次いで、この混合粉末を、自然雰囲気中において、９００℃の温度で仮焼し、粉砕することによって、実施例５に係る変性ＡＢＯ₃ 粉末を得た。
【００９４】
次に、上述の変性ＡＢＯ₃ 粉末に、表１の「仮焼粉末の残部」の欄に示した組成比となるように、前述の仮焼粉末の残部を配合するとともに、表１の「その他」および「焼結助剤」の各欄に示した組成比となるように、Ｙｂ₂ Ｏ₃ およびＢａＣＯ₃ ならびに実施例１の場合と同様の組成の焼結助剤を配合し、実施例５に係る誘電体セラミック原料粉末を得た。
【００９５】
（実施例６）
主成分としてのＡＢＯ₃ において、Ａを含む化合物として、ＢａＣＯ₃ 、ＣａＣＯ₃ およびＳｒＣＯ₃ を用意し、Ｂを含む化合物として、ＴｉＯ₂ を用意した。次いで、これらの粉末を、表１の「ＡＢＯ₃ 」の欄に示した組成比となるように秤量し、純水を加えてボールミルにより２４時間湿式混合した後、蒸発乾燥した。次いで、この混合粉末を、自然雰囲気中において、１１００℃の温度で仮焼してＡＢＯ₃ を合成し、粉砕することによって、実施例６に係るＡＢＯ₃ 粉末を得た。
【００９６】
他方、添加成分として、Ｙ₂ Ｏ₃ 、Ｙｂ₂ Ｏ₃ 、ＣｏＯおよびＦｅ₂ Ｏ₃ を用意し、これらの粉末を、表１の「Ｒ成分」および「Ｍ成分」の各欄に示した組成比となるように秤量し、ボールミルにより湿式混合した後、１０００℃の温度で仮焼し、次いで粉砕することによって、実施例６に係る仮焼粉末を得た。
【００９７】
次に、上述のＡＢＯ₃ 粉末と仮焼粉末の一部とを、表１に示した「ＡＢＯ₃ 」および「仮焼粉末の一部」の各欄に示した組成比となるように秤量し、純水を加えてボールミルにより２４時間湿式混合した後、蒸発乾燥した。次いで、この混合粉末を、自然雰囲気中において、９００℃の温度で仮焼し、粉砕することによって、実施例６に係る変性ＡＢＯ₃ 粉末を得た。
【００９８】
次に、上述の変性ＡＢＯ₃ 粉末に、表１の「仮焼粉末の残部」の欄に示した組成比となるように、前述の仮焼粉末の残部を配合するとともに、表１の「その他」および「焼結助剤」の各欄に示した組成比となるように、ＢａＣＯ₃ および実施例１の場合と同様の組成の焼結助剤を配合し、実施例６に係る誘電体セラミック原料粉末を得た。
【００９９】
（実施例７）
主成分としてのＡＢＯ₃ において、Ａを含む化合物として、ＢａＣＯ₃ を用意し、Ｂを含む化合物として、ＴｉＯ₂ 、ＺｒＯ₂ およびＨｆＯ₂ を用意した。次いで、これらの粉末を、表１の「ＡＢＯ₃ 」の欄に示した組成比となるように秤量し、純水を加えてボールミルにより２４時間湿式混合した後、蒸発乾燥した。次いで、この混合粉末を、自然雰囲気中において、１１００℃の温度で仮焼してＡＢＯ₃ を合成し、粉砕することによって、実施例７に係るＡＢＯ₃ 粉末を得た。
【０１００】
他方、添加成分として、Ｇｄ₂ Ｏ₃ およびＭｎＯ₂ を用意し、これらの粉末を、表１の「Ｒ成分」および「Ｍ成分」の各欄に示した組成比となるように秤量し、ボールミルにより湿式混合した後、１０００℃の温度で仮焼し、次いで粉砕することによって、実施例７に係る仮焼粉末を得た。
【０１０１】
次に、上述のＡＢＯ₃ 粉末と仮焼粉末の一部とを、表１に示した「ＡＢＯ₃ 」および「仮焼粉末の一部」の各欄に示した組成比となるように秤量し、純水を加えてボールミルにより２４時間湿式混合した後、蒸発乾燥した。次いで、この混合粉末を、自然雰囲気中において、９００℃の温度で仮焼し、粉砕することによって、実施例７に係る変性ＡＢＯ₃ 粉末を得た。
【０１０２】
次に、上述の変性ＡＢＯ₃ 粉末に、表１の「仮焼粉末の残部」の欄に示した組成比となるように、前述の仮焼粉末の残部を配合するとともに、表１の「その他」および「焼結助剤」の各欄に示した組成比となるように、ＭｇＯおよびＢａＣＯ₃ ならびに実施例１の場合と同様の組成の焼結助剤を配合し、実施例７に係る誘電体セラミック原料粉末を得た。
【０１０３】
（比較例１）
比較例１では、実施例１の場合と同じ組成の誘電体セラミックの原料粉末を、実施例１の場合と異なる方法によって作製した。
【０１０４】
まず、実施例１と同じ組成かつ同じ方法にて、表２の「ＡＢＯ₃ 」の欄に示すように、比較例１に係るＡＢＯ₃ 粉末を得た。
【０１０５】
次に、添加成分としてのＨｏ₂ Ｏ₃ を用意し、この粉末を、表２の「仮焼粉末の一部」における「Ｒ成分」の欄に示した組成比となるように秤量し、これを、上述のＡＢＯ₃ 粉末に加えるとともに純水を加えてボールミルにより２４時間湿式混合した後、蒸発乾燥した。次いで、この混合粉末を、自然雰囲気中において、９００℃の温度で仮焼し、粉砕することによって、比較例１に係る変性ＡＢＯ₃ 粉末を得た。
【０１０６】
次に、上述の変性ＡＢＯ₃ 粉末に、表２の「仮焼粉末の残部」における「Ｒ成分」の欄に示した組成比をもって、Ｈｏ₂ Ｏ₃ を配合するとともに、表２の「その他」および「焼結助剤」の各欄に示した組成比となるように、ＭｎＯ₂ 、ＭｇＯおよびＢａＣＯ₃ ならびに実施例１の場合と同様の組成を有する焼結助剤を配合し、比較例１に係る誘電体セラミック原料粉末を得た。
【０１０７】
（比較例２）
比較例２では、実施例２の場合と同じ組成の誘電体セラミックの原料粉末を、実施例２の場合と異なる方法によって作製した。
【０１０８】
まず、実施例２と同じ組成かつ同じ方法にて、表２の「ＡＢＯ₃ 」の欄に示すように、比較例２に係るＡＢＯ₃ 粉末を得た。
【０１０９】
次に、添加成分としてのＭｎＯ₂ およびＣｒ₂ Ｏ₃ を用意し、これらの粉末を、表２の「Ｍ成分」の欄に示した組成比となるように秤量し、ボールミルにより湿式混合した後、１０００℃の温度で仮焼し、次いで粉砕することによって、比較例２に係る仮焼粉末を得た。
【０１１０】
次に、上述のＡＢＯ₃ 粉末と仮焼粉末の一部とを、表２に示した「ＡＢＯ₃ 」および「仮焼粉末の一部」の各欄に示した組成比となるように秤量し、純水を加えてボールミルにより２４時間湿式混合した後、蒸発乾燥した。次いで、この混合粉末を、自然雰囲気中において、９００℃の温度で仮焼し、粉砕することによって、比較例２に係る変性ＡＢＯ₃ 粉末を得た。
【０１１１】
次に、上述の変性ＡＢＯ₃ 粉末に、表２の「仮焼粉末の残部」の欄に示した組成比となるように、前述の仮焼粉末の残部を配合するとともに、表２の「その他」および「焼結助剤」の各欄に示した組成比となるように、Ｓｍ₂ Ｏ₃ 、Ｙ₂ Ｏ₃ およびＢａＣＯ₃ ならびに実施例１の場合と同様の組成の焼結助剤を配合し、比較例２に係る誘電体セラミック原料粉末を得た。
【０１１２】
（比較例３）
比較例３では、まず、実施例３と同じ組成かつ同じ方法にて、表２の「ＡＢＯ₃ 」の欄に示すように、比較例３に係るＡＢＯ₃ 粉末を得た。
【０１１３】
次に、添加成分としてのＥｒ₂ Ｏ₃ およびＣｏＯを用意し、これらの粉末を、表２の「Ｒ成分」および「Ｍ成分」の各欄に示した組成比となるように秤量し、ボールミルにより湿式混合した後、１０００℃の温度で仮焼し、次いで粉砕することによって、比較例３に係る仮焼粉末を得た。ここで、「Ｒ成分」であるＥｒ₂ Ｏ₃ が、「Ｍ成分」であるＣｏＯより少ない比率となっていることに注目すべきである。
【０１１４】
次に、上述のＡＢＯ₃ 粉末と仮焼粉末の一部とを、表２に示した「ＡＢＯ₃ 」および「仮焼粉末の一部」の各欄に示した組成比となるように秤量し、純水を加えてボールミルにより２４時間湿式混合した後、蒸発乾燥した。次いで、この混合粉末を、自然雰囲気中において、９００℃の温度で仮焼し、粉砕することによって、比較例３に係る変性ＡＢＯ₃ 粉末を得た。
【０１１５】
次に、上述の変性ＡＢＯ₃ 粉末に、表２の「仮焼粉末の残部」の欄に示した組成比となるように、前述の仮焼粉末の残部を配合するとともに、表２の「その他」および「焼結助剤」の各欄に示した組成比となるように、Ｅｒ₂ Ｏ₃ 、Ａｌ₂ Ｏ₃ およびＢａＣＯ₃ ならびに実施例１の場合と同様の組成の焼結助剤を配合し、比較例３に係る誘電体セラミック原料粉末を得た。
【０１１６】
（比較例４）
比較例４では、まず、実施例４と同じ組成かつ同じ方法にて、表２の「ＡＢＯ₃ 」の欄に示すように、比較例４に係るＡＢＯ₃ 粉末を得た。
【０１１７】
次に、上述のＡＢＯ₃ 粉末に、表２の「その他」および「焼結助剤」の各欄に示した組成比となるように、添加成分としてのＬａ₂ Ｏ₃ 、Ｃｒ₂ Ｏ₃ およびＢａＣＯ₃ ならびに実施例１の場合と同様の組成の焼結助剤を配合し、比較例４に係る誘電体セラミック原料粉末を得た。
【０１１８】
（比較例５）
比較例５では、まず、実施例５と同じ組成かつ同じ方法にて、表２の「ＡＢＯ₃ 」の欄に示すように、比較例５に係るＡＢＯ₃ 粉末を得た。
【０１１９】
他方、添加成分として、実施例５の場合と同様、Ｄｙ₂ Ｏ₃ 、ＭｎＯ₂ およびＣｒ₂ Ｏ₃ を用意し、これらの粉末を、表２の「Ｒ成分」および「Ｍ成分」の各欄に示した組成比となるように秤量し、ボールミルにより湿式混合した後、１０００℃の温度で仮焼し、次いで粉砕することによって、比較例５に係る仮焼粉末を得た。ここで、「Ｒ成分」であるＤｙ₂ Ｏ₃ が、「Ｍ成分」であるＭｎＯ₂ およびＣｒ₂ Ｏ₃ より少ない比率となっていることに注目すべきである。
【０１２０】
次に、上述のＡＢＯ₃ 粉末と仮焼粉末の一部とを、表２に示した「ＡＢＯ₃ 」および「仮焼粉末の一部」の各欄に示した組成比となるように秤量し、純水を加えてボールミルにより２４時間湿式混合した後、蒸発乾燥した。次いで、この混合粉末を、自然雰囲気中において、９００℃の温度で仮焼し、粉砕することによって、比較例５に係る変性ＡＢＯ₃ 粉末を得た。
【０１２１】
次に、上述の変性ＡＢＯ₃ 粉末に、表２の「仮焼粉末の残部」の欄に示した組成比となるように、前述の仮焼粉末の残部を配合するとともに、表２の「その他」および「焼結助剤」の各欄に示した組成比となるように、Ｙｂ₂ Ｏ₃ およびＢａＣＯ₃ ならびに実施例１の場合と同様の組成の焼結助剤を配合し、比較例５に係る誘電体セラミック原料粉末を得た。
【０１２２】
（比較例６）
比較例６では、まず、実施例５と同じ組成かつ同じ方法にて、表２の「ＡＢＯ₃ 」の欄に示すように、比較例６に係るＡＢＯ₃ 粉末を得た。
【０１２３】
他方、添加成分として、比較例５の場合と同様、Ｄｙ₂ Ｏ₃ 、ＭｎＯ₂ およびＣｒ₂ Ｏ₃ を用意し、これらの粉末を、表２の「Ｒ成分」および「Ｍ成分」の各欄に示した組成比となるように秤量し、ボールミルにより湿式混合した後、１０００℃の温度で仮焼し、次いで粉砕することによって、比較例６に係る仮焼粉末を得た。ここで、比較例６に係る仮焼粉末は、比較例５に係る仮焼粉末と同じ組成であり、「Ｒ成分」であるＤｙ₂ Ｏ₃ が、「Ｍ成分」であるＭｎＯ₂ およびＣｒ₂ Ｏ₃ より少ない比率となっていることに注目すべきである。
【０１２４】
次に、上述のＡＢＯ₃ 粉末に、表２の「仮焼粉末の残部」の欄に示した組成比となるように、上述の仮焼粉末のすべてを配合するとともに、表２の「その他」および「焼結助剤」の各欄に示した組成比となるように、Ｙｂ₂ Ｏ₃ およびＢａＣＯ₃ ならびに実施例１の場合と同様の組成の焼結助剤を配合し、比較例６に係る誘電体セラミック原料粉末を得た。
【０１２５】
２．積層セラミックコンデンサの作製
次に、上述の実施例１〜７および比較例１〜６の各々に係る誘電体セラミック原料粉末に、ポリビニルブチラール系バインダおよびエタノール等の有機溶剤を加え、ボールミルを用いた湿式混合を実施することによって、セラミックスラリーを作製した。
【０１２６】
次に、セラミックスラリーを、ドクターブレード法によって、焼成後の誘電体セラミック層の厚みが３μｍになるような厚みをもってシート状に成形し、矩形のセラミックグリーンシートを得た。
【０１２７】
次に、セラミックグリーンシート上に、ニッケルを主体とする導電性ペーストをスクリーン印刷し、内部電極となるべき導電性ペースト膜を形成した。
【０１２８】
次いで、導電性ペースト膜が引き出されている側が互い違いとなるように、導電性ペースト膜が形成されたセラミックグリーンシートを含む複数のセラミックグリーンシートを積層し、生の積層体を得た。
【０１２９】
次に、生の積層体を、窒素雰囲気中において３５０℃の温度に加熱し、バインダを燃焼させた後、酸素分圧１０^-9〜１０^-12 ＭＰａのＨ₂ −Ｎ₂ −Ｈ₂ Ｏガスからなる還元性雰囲気中において、後掲の表３に示す焼成温度にて２時間焼成し、焼結した積層体を得た。
【０１３０】
次いで、積層体の両端面上に、Ｂ₂ Ｏ₃ −Ｌｉ₂ Ｏ−ＳｉＯ₂ −ＢａＯ系のガラスフリットを含有するとともに銀を導電成分とする導電性ペーストを塗布し、窒素雰囲気中において８００℃の温度で焼き付け、内部電極と電気的に接続された外部電極を形成した。
【０１３１】
このようにして得られた積層セラミックコンデンサの外形寸法は、幅１．６ｍｍ、長さ３．２ｍｍおよび厚さ１．２ｍｍであり、内部電極間に介在する誘電体セラミック層の厚みは、３μｍであった。また、有効誘電体セラミック層の数は１００であり、１層あたりの対向電極面積は２．１ｍｍ² であった。
【０１３２】
３．電気的特性の測定
このようにして得られた実施例１〜７および比較例１〜６に係る積層セラミックコンデンサの各種電気的特性を測定した。
【０１３３】
まず、各積層セラミックコンデンサの室温での誘電率εおよび絶縁抵抗を測定した。この場合、誘電率εは、温度２５℃、１ｋＨｚ、および１Ｖ_rms の条件下で測定した。また、５ｋＶ／ｍｍの電界強度の下で絶縁抵抗を測定するため、１５Ｖの直流電圧を２分間印加して、＋２５℃において絶縁抵抗を測定し、静電容量（Ｃ）と絶縁抵抗（Ｒ）との積、すなわちＣＲ積を求めた。
【０１３４】
また、温度変化に対する静電容量の変化率を求めた。この温度変化に対する静電容量の変化率については、ＪＩＳ規格のＢ特性すなわち２０℃での静電容量を基準とした−２５℃での変化率および８５℃での変化率（ΔＣ／Ｃ₂₀）と、ＥＩＡ規格のＸ７Ｒ特性すなわち２５℃での静電容量を基準とした−５５℃での変化率および１２５℃での変化率（ΔＣ／Ｃ₂₅）とを評価した。
【０１３５】
また、高温負荷寿命試験を実施した。高温負荷寿命試験は、３６個の試料について、温度１５０℃において、電界強度が２０ｋＶ／ｍｍになるように６０Ｖの電圧を印加して、その絶縁抵抗の経時変化を求めようとしたものである。なお、高温負荷寿命として、各試料の絶縁抵抗値が２００ｋΩ以下になったときの時間を寿命時間として、その平均寿命時間を求めた。
【０１３６】
また、直流電圧印加下での静電容量の経時変化を求めた。静電容量の経時変化は、温度８５℃、１ｋＨｚ、１Ｖ_rms 、および直流電圧３．１５Ｖ印加の条件下で、１００時間後の容量変化を測定し、直流電圧印加直後の８５℃での静電容量を基準としてＤＣ負荷経時変化率を求めたものである。
【０１３７】
以上の誘電率ε、ＣＲ積、温度特性（ΔＣ／Ｃ₂₀およびΔＣ／Ｃ₂₅）、平均寿命時間ならびに静電容量の経時変化が、表３に示されている。
【０１３８】
【表３】

【０１３９】
４．微細構造の調査
実施例１〜７および比較例１〜６に係る積層セラミックコンデンサについて、その誘電体セラミック層を構成する誘電体セラミックの微細構造を調査した。より具体的には、次のような調査を行なった。
【０１４０】
まず、試料としての積層セラミックコンデンサを、内部電極が延びる面に直角に研磨し、誘電体セラミック層を露出させた。次に、透過型電子顕微鏡を用いたエネルギー分散型Ｘ線分光法（ＥＤＸ）により、図２に示すように、結晶粒子２１の中央部に位置する分析点２５、結晶粒子２１の径に対して表面から５％までの領域（表面近傍領域）に位置する分析点２３、および結晶粒界２２に位置する分析点２４の各々でのＲおよびＭの濃度分析を行なった。なお、分析のための電子線としては、２ｎｍのプローブを用いた。
【０１４１】
ここで、結晶粒子２１の表面近傍領域および結晶粒界２２については、より具体的には、無作為に５個以上の結晶粒子２１を選択し、選択された各々の結晶粒子２１の外周をほぼ４等分する、任意の４点をそれぞれの分析点２３および２４とした。また、結晶粒界２２の分析については、２つの結晶粒子２１により形成される領域から選ぶ場合も、３つ以上の結晶粒子２１により形成される領域から選ぶ場合もあった。また、同一の結晶粒子２１間に形成される結晶粒界２２での分析を避けるようにした。
【０１４２】
このような分析の結果、Ｒの濃度をＣ_R とし、Ｍの濃度をＣ_M としたとき、結晶粒子の表面近傍に位置する分析点に関して、Ｃ_R ／Ｃ_M ＞１の条件を満足する分析点の割合を算出した。その結果が、表４の「表面近傍濃度条件満足割合」の欄に示されている。
【０１４３】
また、結晶粒界に位置する分析点に関して、Ｃ_R ／Ｃ_M ＞１の条件を満足する分析点の割合を算出した。その結果が、表４の「粒界濃度条件満足割合」の欄に示されている。
【０１４４】
また、結晶粒子の中央部におけるＣ_R およびＣ_M が、それぞれ、結晶粒子の表面近傍領域におけるＣ_R およびＣ_M の各最大値の１／１０以下であるという条件を満足する、結晶粒子の個数の割合を算出した。その結果が、表４の「中央部濃度条件満足割合」の欄に示されている。
【０１４５】
また、試料としての積層セラミックコンデンサを破断して熱エッチングした面を走査型電子顕微鏡を用いて写真撮影し、得られた写真から結晶粒子の粒子径を求めた。そして、無作為に１０個以上の結晶粒子を選択し、その粒子径の平均値を求め、平均粒子径とした。その結果が、表４の「結晶粒子の平均粒子径」の欄に示されている。
【０１４６】
【表４】

【０１４７】
５．総合評価
まず、実施例１と比較例１との間で比較する。
【０１４８】
実施例１では、表４に示すように、「表面近傍濃度条件満足割合」は８９％であり、「粒界濃度条件満足割合」は９５％であり、しかも「中央部濃度条件満足割合」が７３％である。他方、比較例１では、「表面近傍濃度条件満足割合」は８６％であるが、「粒界濃度条件満足割合」は４５％にすぎず、「中央部濃度条件満足割合」は５３％である。
【０１４９】
その結果、実施例１および比較例１では、表３に示すように、誘電率およびＣＲ積については、ほぼ変わらない値、すなわち、ともに、誘電率が２７００であり、ＣＲ積が３０００程度の値を示した。
【０１５０】
しかしながら、温度特性については、実施例１では、ＥＩＡ規格のＸ７Ｒ特性を満足しているのに対し、比較例１では、この特性を満足していない。また、平均寿命時間については、実施例１では、２１４時間と長く、高い信頼性を示しているのに対し、比較例１では、３６時間と短く、十分な信頼性が得られていない。また、静電容量の経時変化についても、実施例１では、−４．５％というように、比較例１の−１６．３％と比較して、良好な結果が得られている。
【０１５１】
実施例２〜７についても、実施例１と同様、優れた結果が得られている。
【０１５２】
すなわち、実施例２〜７では、表４に示すように、「表面近傍濃度条件満足割合」はそれぞれ６０％以上であり、「粒界濃度条件満足割合」はそれぞれ６０％以上であり、しかも「中央部濃度条件満足割合」は５０％以上である。
【０１５３】
その結果、表３に示すように、実施例２〜７のいずれについても、温度特性がＥＩＡ規格のＸ７Ｒ特性を満足し、ＣＲ積が高く、平均寿命時間が長く、それゆえ信頼性に優れ、静電容量の経時変化も小さい。
【０１５４】
これに対して、比較例２では、表４に示すように、「表面近傍濃度条件満足割合」は３３％であり、「粒界濃度条件満足割合」は８４％であり、「中央部濃度条件満足割合」は６８％である。その結果、比較例２では、表３に示すように、平均寿命時間が２０時間と短く、十分な信頼性が得られず、また、静電容量の経時変化が−１４．１％と大きい絶対値を示している。
【０１５５】
比較例３では、表４に示すように、「表面近傍濃度条件満足割合」は５６％であり、「粒界濃度条件満足割合」は９３％であり、「中央部濃度条件満足割合」は７５％である。その結果、比較例３では、表３に示すように、平均寿命時間が６７時間と短く、十分な信頼性が得られず、また、静電容量の経時変化が−１２．３％と大きい絶対値を示している。
【０１５６】
比較例４では、表４に示すように、「表面近傍濃度条件満足割合」は６２％であり、「粒界濃度条件満足割合」は５８％であり、「中央部濃度条件満足割合」は３０％である。その結果、比較例４では、表３に示すように、平均寿命時間が６時間と短く、十分な信頼性が得られず、静電容量の経時変化が−１９．１％と大きい絶対値を示し、また、温度特性については、ＥＩＡ規格のＸ７Ｒ特性を満足していない。
【０１５７】
比較例５では、表４に示すように、「表面近傍濃度条件満足割合」は４５％であり、「粒界濃度条件満足割合」は８０％であり、「中央部濃度条件満足割合」は８４％である。その結果、比較例５では、表３に示すように、平均寿命時間が３３時間と短く、十分な信頼性が得られず、また、静電容量の経時変化が−１５．０％と大きい絶対値を示している。
【０１５８】
比較例６では、表４に示すように、「表面近傍濃度条件満足割合」は５３％であり、「粒界濃度条件満足割合」は７２％であり、「中央部濃度条件満足割合」は７０％である。その結果、比較例６では、表３に示すように、平均寿命時間が４５時間と短く、十分な信頼性が得られず、また、静電容量の経時変化が−１３．８％と大きい絶対値を示している。
【０１５９】
【発明の効果】
以上のように、この発明に係る誘電体セラミックによれば、ＡＢＯ₃ （Ａは、Ｂａ、またはＢａならびにその一部が置換されたＣａおよびＳｒの少なくとも１種であり、Ｂは、Ｔｉ、またはＴｉならびにその一部が置換されたＺｒおよびＨｆの少なくとも１種である。）で表わされる主成分と、Ｒ（Ｒは、Ｌａ、Ｃｅ、Ｐｒ、Ｎｄ、Ｓｍ、Ｅｕ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｙｂ、ＬｕおよびＹのうちの少なくとも１種である。）およびＭ（Ｍは、Ｍｎ、Ｃｏ、ＦｅおよびＣｒのうちの少なくとも１種である。）を含む添加成分とを含む組成を有し、かつＡＢＯ₃ を主成分とする結晶粒子と結晶粒子間を占める結晶粒界とからなるものにおいて、Ｒの濃度をＣ_R とし、Ｍの濃度をＣ_M としたとき、結晶粒子の径に対して表面から５％までの領域（表面近傍領域）に位置する分析点および結晶粒界に位置する複数の分析点について、それぞれの６０％以上の分析点において、Ｃ_R ／Ｃ_M ＞１の条件を満足するので、これを用いて積層セラミックコンデンサを構成したとき、誘電率の温度変化および直流電圧印加下での静電容量の経時変化が小さく、絶縁抵抗と静電容量との積（ＣＲ積）が高く、高温かつ高電圧下における絶縁抵抗の加速寿命を長くすることができる。
【０１６０】
そのため、この誘電体セラミックをもって積層セラミックコンデンサの誘電体セラミック層を構成すれば、誘電体セラミック層の薄層化に対しても、優れた信頼性を維持し得る積層セラミックコンデンサを得ることができる。
【０１６１】
したがって、誘電体セラミック層の薄層化によって、積層セラミックコンデンサの小型化かつ大容量化が可能となり、また、誘電体セラミック層を薄層化しても、積層セラミックコンデンサの定格電圧を下げる必要がない。その結果、たとえば、誘電体セラミック層の厚みを３μｍ程度にまで薄層化することが問題なく行なうことができる。
【０１６２】
この発明に係る誘電体セラミックにおいて、結晶粒子の中央部における分析点でのＣ_R およびＣ_M が、それぞれ、結晶粒子の表面近傍領域における分析点でのＣ_R およびＣ_M の各最大値の１／１０以下である、結晶粒子の個数の割合が５０％以上となるようにされると、温度特性が悪化や、粒成長を引き起こしての信頼性の低下を確実に防止することができる。
【０１６３】
また、この発明に係る誘電体セラミックに、ＳｉＯ₂ 、Ｌｉ₂ ＯおよびＢ₂ Ｏ₃ （酸化ホウ素）から選ばれた少なくとも１種を主成分とする焼結助剤を含有させると、誘電体セラミックの焼結温度を低温化させたり、ＣＲ積や高温高電圧下における絶縁抵抗の加速寿命をより向上させることが可能になる。
【０１６４】
また、この発明に係る誘電体セラミックを構成する結晶粒子の平均粒子径が、０．５μｍ以下となるようにされると、積層セラミックコンデンサに備える誘電体セラミック層の薄層化により適切に対応できるようになる。
【０１６５】
他方、この発明に係る誘電体セラミックの製造方法によれば、上述のＡＢＯ₃ を合成し、次いで粉砕することによって、ＡＢＯ₃ 粉末を得る工程と、上述のＲを含むＲ化合物を用意する工程と、上述のＭを含むＭ化合物を用意する工程と、Ｒ化合物とＭ化合物とを、Ｒ化合物の比率が多くなるように混合し、得られた混合物を仮焼し、次いで粉砕することによって、仮焼粉末を得る工程と、ＡＢＯ₃ 粉末と仮焼粉末の一部とを混合し、得られた混合物を仮焼し、次いで粉砕することによって、変性ＡＢＯ₃ 粉末を得る工程と、変性ＡＢＯ₃ 粉末と仮焼粉末の残部とを含む混合粉末を焼成する工程とを備えているので、前述したような濃度条件を満足する誘電体セラミックを容易かつ確実に製造することができる。
【図面の簡単な説明】
【図１】この発明の一実施形態による積層セラミックコンデンサ１を図解的に示す断面図である。
【図２】誘電体セラミックを構成する、ＡＢＯ₃ を主成分とする結晶粒子２１と結晶粒子２１間を占める結晶粒界２２と図解的に示す断面図であり、結晶粒子２１の表面近傍領域に位置する分析点２３、結晶粒界２２に位置する分析点２４および結晶粒子２１の中央部に位置する分析点２５の各例を示している。
【符号の説明】
１ 積層セラミックコンデンサ
２ 積層体
３ 誘電体セラミック層
４，５ 内部電極
８，９ 外部電極
２１ 結晶粒子
２２ 結晶粒界
２３ 結晶粒子の表面近傍領域に位置する分析点
２４ 結晶粒界に位置する分析点
２５ 結晶粒子の中央部に位置する分析点[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a dielectric ceramic, a method of manufacturing the same, and a multilayer ceramic capacitor formed by using the dielectric ceramic. In particular, the present invention can advantageously reduce the thickness of a dielectric ceramic layer in a multilayer ceramic capacitor. It is related to the improvement for
[0002]
[Prior art]
A multilayer ceramic capacitor is generally manufactured as follows.
[0003]
First, a ceramic green sheet containing a dielectric ceramic raw material powder having a surface provided with a conductive material to be an internal electrode in a desired pattern is prepared. As the dielectric ceramic, for example, BaTiO _Three Is used as a main component.
[0004]
Next, a plurality of ceramic green sheets including the above-described ceramic green sheet provided with the conductive material are laminated and thermocompression-bonded, thereby producing an integrated raw laminate.
[0005]
Next, the green laminate is fired, thereby obtaining a sintered laminate. An internal electrode made of the above-described conductive material is formed inside the laminate.
[0006]
Next, external electrodes are formed on the outer surface of the laminate so as to be electrically connected to specific ones of the internal electrodes. The external electrode is formed, for example, by applying a conductive paste containing a conductive metal powder and a glass frit on the outer surface of the laminate and baking the paste.
[0007]
Thus, a multilayer capacitor is completed.
[0008]
In recent years, a relatively inexpensive base metal such as nickel or copper has often been used as a conductive material for the above-mentioned internal electrodes in order to minimize the manufacturing cost of the multilayer ceramic capacitor. However, when manufacturing a multilayer ceramic capacitor in which an internal electrode is formed with a base metal, firing in a neutral or reducing atmosphere must be applied to prevent oxidation of the base metal during firing. The dielectric ceramic used in the multilayer ceramic capacitor must have reduction resistance.
[0009]
As dielectric ceramics having the above-described reduction resistance, for example, Japanese Patent Application Laid-Open Nos. 5-9066 (Patent Document 1), 5-9067 (Patent Document 2), and 5-9068 ( In Patent Document 3), BaTiO _Three -Rare earth oxide-Co _Two O _Three The composition of the system has been proposed.
[0010]
Further, JP-A-6-5460 (Patent Document 4), JP-A-9-270366 (Patent Document 5) and JP-A-2001-230149 (Patent Document 6) show a high dielectric constant, A dielectric ceramic having a small temperature change and a long high-temperature load life has been proposed.
[0011]
[Patent Document 1]
JP-A-5-9066
[Patent Document 2]
JP-A-5-9067
[Patent Document 3]
JP-A-5-9068
[Patent Document 4]
JP-A-6-5460
[Patent Document 5]
JP-A-9-270366
[Patent Document 6]
JP 2001-230149 A
[0012]
[Problems to be solved by the invention]
With the development of electronics technology in recent years, the miniaturization of electronic components has been rapidly progressing, and the tendency of multilayer ceramic capacitors to be smaller and have a larger capacity has become remarkable.
[0013]
Therefore, even in a firing atmosphere in which the base metal used for the internal electrode is not oxidized, the dielectric constant is high, the temperature change and the change over time of the dielectric constant are small, and even if the dielectric ceramic layer is thinned, the electric insulation is high, Therefore, there is a strong demand for a dielectric ceramic having excellent reliability. However, the conventional dielectric ceramics as described above cannot always sufficiently satisfy this requirement.
[0014]
For example, the dielectric ceramics described in Patent Literatures 1 to 3 satisfy the X7R characteristics in the EIA standard and exhibit high electrical insulation, but when the dielectric ceramic layer is thinned, specifically, 5 μm In the following, in particular, when the thickness is reduced to 3 μm or less, the reliability cannot be sufficiently satisfied in the market.
[0015]
In addition, the dielectric ceramic described in Patent Document 4 uses BaTiO used. _Three Because of the large particle size, the reliability decreases as the dielectric ceramic layer becomes thinner, and there is a problem that the capacitance changes with time greatly.
[0016]
Also, as for the dielectric ceramic having the structure described in Patent Document 5, the reliability decreases as the dielectric ceramic layer becomes thinner, and the capacitance changes with time under the application of a DC voltage. There is a problem that is large.
[0017]
Further, the dielectric ceramic described in Patent Document 6 is prepared by mixing MgO and BaTiO in advance at the time of mixing raw materials. _Three Is used in the process of adding a rare earth element to the reaction of the rare earth element, so that the rare earth element hardly forms a solid solution in the grains, and therefore segregates at a high concentration at grain boundaries and triple points. In addition, the charge balance between the donor and the acceptor at the grain boundaries deteriorates, and as the dielectric ceramic layer becomes thinner, the reliability decreases, and the change with time in the capacitance under the application of a DC voltage increases. There's a problem.
[0018]
From the above, when the dielectric ceramic layer is made thinner in order to respond to the miniaturization and large capacity of the multilayer ceramic capacitor, if the rated voltage is the same as before the thinning, the dielectric Since the intensity of the electric field applied to one ceramic layer increases, the insulation resistance at room temperature or high temperature decreases, and the reliability is significantly reduced. Therefore, when a conventional dielectric ceramic is used, it is necessary to lower the rated voltage when thinning the dielectric ceramic layer.
[0019]
Therefore, it is desired to realize a multilayer ceramic capacitor which does not need to lower the rated voltage while reducing the thickness of the dielectric ceramic layer, has high insulation resistance under a high electric field strength, and has excellent reliability. .
[0020]
Further, since a multilayer ceramic capacitor is usually used in a state where a DC voltage is applied, it is known that the capacitance changes with time. However, as a result of the reduction in the thickness of the dielectric ceramic layer accompanying the miniaturization and large capacity of the multilayer ceramic capacitor, the DC electric field strength per one dielectric ceramic layer increases, and the change with time of the capacitance becomes larger. Problem.
[0021]
Therefore, a multilayer ceramic capacitor that has a small change in capacitance with time when a DC voltage is applied is desired.
[0022]
Therefore, an object of the present invention is to provide a high dielectric constant, a small change in dielectric constant with temperature and a change with time under application of a DC voltage, a high product of insulation resistance and capacitance (CR product), a high temperature and a high voltage. An object of the present invention is to provide a dielectric ceramic and a method of manufacturing the same, which can form a multilayer ceramic capacitor having a long accelerated life of an insulation resistance below.
[0023]
Another object of the present invention is to provide a multilayer ceramic capacitor constituted by using the above-described dielectric ceramic, which has excellent reliability even when the dielectric ceramic layer is thinned.
[0024]
[Means for Solving the Problems]
The present invention relates to ABO _Three (A is Ba or at least one of Ba and partially substituted Ca and Sr, and B is Ti or at least one of Ti and partially substituted Zr and Hf. .) And at least one of R, R, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y And M (where M is at least one of Mn, Co, Fe and Cr), and ABO. _Three The present invention is directed to a dielectric ceramic, which is composed of crystal grains mainly composed of and crystal grain boundaries occupying spaces between the crystal grains, and is characterized by having the following configuration.
[0025]
That is, if the concentration of R is C _R And the concentration of M is C _M As for the analysis points located in the region up to 5% from the surface with respect to the diameter of the crystal grains and the plurality of analysis points located in the crystal grain boundaries, C is determined at 60% or more of each analysis point _R / C _M > 1 is satisfied.
[0026]
In the dielectric ceramic according to the present invention, when the number of crystal grains is 50% or more, the C _R And C _M , Respectively, in the region up to 5% from the surface with respect to the diameter of the crystal grain. _R And C _M It is preferable to satisfy the condition that it is 1/10 or less of each maximum value.
[0027]
Further, the dielectric ceramic according to the present invention is made of SiO 2 _Two , Li _Two O and B _Two O _Three It may further include a sintering aid containing at least one selected from (boron oxide) as a main component.
[0028]
Further, in the dielectric ceramic according to the present invention, it is preferable that the average particle size of the crystal particles is 0.5 μm or less.
[0029]
The invention is also directed to a method for producing a dielectric ceramic as described above.
[0030]
The method for producing a dielectric ceramic according to the present invention comprises the steps of: _Three (A is Ba or at least one of Ba and partially substituted Ca and Sr, and B is Ti or at least one of Ti and partially substituted Zr and Hf. .) And then crushed to give ABO _Three A step of obtaining a powder, and R (R is at least one of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y) A step of preparing an R compound containing M; a step of preparing an M compound containing M (M is at least one of Mn, Co, Fe and Cr); Mixing the R compound to increase the ratio thereof, calcining the resulting mixture, and then pulverizing the mixture to obtain a calcined powder; _Three The powder is mixed with a part of the calcined powder, and the resulting mixture is calcined and then pulverized to obtain a modified ABO. _Three Step of obtaining powder, modified ABO _Three Baking a mixed powder containing the powder and the remainder of the calcined powder.
[0031]
Modified ABO subjected to the above calcination step _Three If necessary, a predetermined additive may be added to the mixed powder containing the powder and the remainder of the calcined powder.
[0032]
The present invention is further directed to a multilayer ceramic capacitor formed using the above-described dielectric ceramic.
[0033]
A multilayer ceramic capacitor according to the present invention includes a plurality of stacked dielectric ceramic layers and a plurality of internal electrodes formed along a specific interface between the plurality of dielectric ceramic layers and overlapping in a stacking direction. And an external electrode formed on the outer surface of the laminate so as to be electrically connected to a specific one of the internal electrodes, wherein the dielectric ceramic layer is made of the dielectric ceramic as described above. It is characterized by becoming.
[0034]
In the multilayer ceramic capacitor described above, the present invention is particularly advantageously applied when the internal electrode contains a base metal or the external electrode contains a base metal.
[0035]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a sectional view schematically showing a multilayer ceramic capacitor 1 according to one embodiment of the present invention.
[0036]
The multilayer ceramic capacitor 1 includes a multilayer body 2. The laminate 2 includes a plurality of dielectric ceramic layers 3 to be laminated, and a plurality of internal electrodes 4 and 5 respectively formed along a plurality of specific interfaces between the plurality of dielectric ceramic layers 3. You. The internal electrodes 4 and 5 are formed so as to reach the outer surface of the multilayer body 2. The internal electrodes 4 are extended to one end face 6 of the multilayer body 2 and the internal electrode is extended to the other end face 7. 5 are alternately arranged inside the laminate 2.
[0037]
External electrodes 8 and 9 are formed on the outer surface of the laminate 2 and on the end faces 6 and 7 by applying a conductive paste and then baking the conductive paste. Further, first plating layers 10 and 11 are respectively formed on external electrodes 8 and 9 as necessary, and second plating layers 12 and 13 are further formed thereon, respectively.
[0038]
Thus, in the multilayer ceramic capacitor 1, the plurality of internal electrodes 4 and 5 are formed in a state of being overlapped with each other in the stacking direction of the multilayer body 2, whereby the capacitance between the adjacent internal electrodes 4 and 5 is reduced. To form In addition, the internal electrode 4 and the external electrode 8 are electrically connected, and the internal electrode 5 and the external electrode 9 are electrically connected. The capacitance is taken out.
[0039]
The dielectric ceramic layer 3 is made of the following dielectric ceramic which is a feature of the present invention.
[0040]
That is, ABO _Three (A is Ba or at least one of Ba and partially substituted Ca and Sr, and B is Ti or at least one of Ti and partially substituted Zr and Hf. .) And at least one of R, R, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y And M (where M is at least one of Mn, Co, Fe and Cr), and ABO. _Three The dielectric ceramic layer 3 is made of a dielectric ceramic, which is composed of crystal grains mainly composed of and crystal grain boundaries occupying spaces between the crystal grains.
[0041]
This dielectric ceramic further has the following features. FIG. 2 shows ABO constituting a dielectric ceramic. _Three FIG. 2 is a cross-sectional view schematically illustrating a crystal grain 21 occupying the main component and a crystal grain boundary 22 occupying the space between the crystal grains 21.
[0042]
The concentration of R described above is C _R And the concentration of M is C _M As shown in FIG. 2, a plurality of analysis points 23 located in a region up to 5% from the surface with respect to the diameter of the crystal particles 21 (region near the surface) and a plurality of analysis points located in the crystal grain boundary 22 are shown in FIG. For point 24, at 60% or more of each of analysis points 23 and 24, C _R / C _M > 1 is satisfied.
[0043]
As mentioned above, C _R / C _M The reason that the analysis points 23 and 24 satisfying the condition of> 1 are 60% or more is that when the analysis points 23 and 24 are less than 60%, the insulation resistance under high temperature and high voltage is caused by the existence of excess oxygen vacancies. This is because the accelerated service life of the film becomes short or the change with time of the dielectric constant under application of a DC voltage becomes large.
[0044]
In addition, as for this dielectric ceramic, if the number of crystal grains 21 is 50% or more, the C _R And C _M Are respectively C at the analysis point 23 in the near-surface region. _R And C _M It is preferable to satisfy the condition that it is 1/10 or less of each maximum value.
[0045]
As described above, C at the analysis point 25 in the center of the crystal grain _R And C _M , Respectively, at the analysis point 23 in the region near the surface of the crystal particle 21. _R And C _M The reason why the ratio of the number of the crystal particles 21 which is 1/10 or less of each maximum value is 50% or more is that if the ratio is less than 50%, the temperature characteristic is deteriorated or grain growth is caused. This is because the reliability may be reduced.
[0046]
The amounts of the added components R and M are not particularly limited, but from the viewpoint of prolonging the high temperature load life, ABO as the main component is used. _Three It is preferable that the amount is 0.1 mol or more with respect to 100 mol. _Three The amount is preferably 10 mol or less based on 100 mol. By combining the means of changing the types and addition amounts of R and M, characteristics control according to market requirements, such as increasing the dielectric constant, increasing the insulation resistance, and extending the high temperature load life, etc. Becomes possible.
[0047]
In addition, SiO 2 is used for the dielectric ceramic. _Two , Li _Two O and B _Two O _Three By adding a sintering aid containing at least one selected from (boron oxide) as a main component, the sintering temperature of the dielectric ceramic can be lowered, the CR product and the insulation resistance under high temperature and high voltage can be reduced. The accelerated life can be further improved.
[0048]
The average particle diameter of the crystal particles 21 constituting the dielectric ceramic is preferably 0.5 μm or less in order to appropriately cope with the reduction of the thickness of the dielectric ceramic layer 3 shown in FIG. When a dielectric ceramic having such an average particle diameter is used, the thickness of the dielectric ceramic layer 3 can be reduced to about 1 μm without any problem.
[0049]
In this specification, the term “grain boundary” refers to a region formed by two crystal grains or a region formed by three or more crystal grains (a so-called triple point). is there. More specifically, if a crystallographically clear layer is observed between the crystal grains in the cross section of the ceramic, this becomes a crystal grain boundary. In the cross section of the ceramic, when no other layer is observed between crystal grains crystallographically and the crystal grains are bonded to each other, a 2 nm region centered on the bonding point and the bonding line forms a crystal. It becomes a grain boundary.
[0050]
ABO, which is the main component, is located at the grain boundaries as described above. _Three The presence of the sintering aid components, Mg, Al, V components, etc., in addition to the components and the additive components R and M, do not substantially reduce the properties of the dielectric ceramic.
[0051]
Next, a method of manufacturing the dielectric ceramic or the multilayer ceramic capacitor 1 shown in FIG. 1 will be described.
[0052]
First, a raw material powder of the dielectric ceramic constituting the dielectric ceramic layer 3 is prepared. This raw material powder is preferably produced as follows.
[0053]
That is, ABO _Three By synthesizing and then grinding _Three A powder is made. On the other hand, an R compound containing R is prepared, and an M compound containing M is prepared.
[0054]
Next, the R compound and the M compound are mixed so that the ratio of the R compound is increased, and the obtained mixture is calcined and then pulverized to prepare a calcined powder containing R and M. You.
[0055]
Next, ABO _Three The powder is mixed with a part of the calcined powder, and the resulting mixture is calcined and then pulverized to obtain a modified ABO. _Three A powder is made.
[0056]
Next, the modified ABO _Three The powder and the remainder of the calcined powder are mixed, and this mixed powder is used as a raw material powder for the dielectric ceramic. A predetermined additive may be added to this mixed powder as needed.
[0057]
By preparing the raw material powder in this manner, it is easy to obtain a dielectric ceramic satisfying the above-described conditions.
[0058]
Next, an organic binder and a solvent are added to and mixed with the raw material powder for the dielectric ceramic obtained as described above, and a slurry is produced. Using this slurry, the dielectric ceramic layer 3 is formed. Is formed.
[0059]
Next, a conductive paste film to be the internal electrodes 4 or 5 is formed on a specific ceramic green sheet by, for example, screen printing. This conductive paste film contains a base metal such as nickel, a nickel alloy, copper or a copper alloy as a conductive component. The internal electrodes 4 and 5 may be formed by a printing method such as a screen printing method, or by, for example, an evaporation method or a plating method.
[0060]
Next, a plurality of ceramic green sheets on which the conductive paste film was formed as described above were laminated, and ceramic green sheets on which no conductive paste film was formed were laminated and pressed together so as to sandwich the ceramic green sheets. After that, a raw laminate to be the laminate 2 is obtained by being cut as necessary. In this green laminate, the conductive paste film has its edge exposed at any one of the end surfaces.
[0061]
Next, the green laminate is fired in a reducing atmosphere. As a result, a laminated body 2 after sintering as shown in FIG. 1 is obtained. Is configured.
[0062]
Next, external electrodes 8 and 9 are formed on end surfaces 6 and 7 of laminated body 2 so as to be electrically connected to the exposed edges of internal electrodes 4 and 5, respectively.
[0063]
As the material of the external electrodes 8 and 9, the same material as that of the internal electrodes 4 and 5 can be used, but silver, palladium, a silver-palladium alloy or the like can also be used. _Two O _Three -SiO _Two -BaO-based glass, B _Two O _Three −Li _Two O-SiO _Two A glass frit made of BaO-based glass or the like can be used. An appropriate material is selected in consideration of the application, the place of use, and the like of the multilayer ceramic capacitor 1.
[0064]
The external electrodes 8 and 9 are usually formed by applying and baking a paste containing the above-described conductive metal powder on the outer surface of the fired laminate 2. It may be formed by coating on the outer surface of the green laminate and baking simultaneously with firing for obtaining the laminate 2.
[0065]
Thereafter, plating of nickel, copper, or the like is performed on the external electrodes 8 and 9 to form first plating layers 10 and 11. Then, plating of solder, tin or the like is performed on the first plating layers 10 and 11 to form second plating layers 12 and 13. The formation of a conductor layer such as the plating layers 10 to 13 on the external electrodes 8 and 9 may be omitted depending on the use of the multilayer ceramic capacitor 1.
[0066]
As described above, the multilayer ceramic capacitor 1 is completed.
[0067]
It should be noted that Al, Sr, Zr, Fe, Hf, Na, and the like may be mixed as impurities at any stage of the production of the raw material powder of the dielectric ceramic and other manufacturing processes of the multilayer ceramic capacitor 1. The mixing of these impurities does not cause a problem on the electrical characteristics of the multilayer ceramic capacitor 1.
[0068]
At any stage of the manufacturing process of the multilayer ceramic capacitor 1, there is a possibility that Fe, Cr, or the like may be mixed into the internal electrodes 4 and 5 as an impurity. It does not become.
[0069]
Further, since the multilayer ceramic capacitor 1 is manufactured by simultaneously firing the dielectric ceramic layer 3 and the internal electrodes 4 and 5, the components of the internal electrodes 4 and 5 change during the firing process. May spread to. When the internal electrodes 4 and 5 are mainly composed of nickel or copper, the amount of diffusion of the nickel or copper element depends on the main component ABO of the dielectric ceramic constituting the dielectric ceramic layer 3. _Three It is preferable that the amount be 5 mol or less based on 100 mol. This is because if nickel or copper is excessively diffused in excess of 5 mol, the reliability of the multilayer ceramic capacitor 1 is reduced.
[0070]
Next, an experimental example performed for confirming the effect of the present invention will be described.
[0071]
[Experimental example]
1. Preparation of raw material powder for dielectric ceramic
Tables 1 and 2 show the composition of the raw material powder of the dielectric ceramic according to each of the manufactured samples.
[0072]
[Table 1]

[0073]
[Table 2]

[0074]
In Tables 1 and 2, except for the sintering aid, the coefficients of the respective components indicate the molar ratio. About sintering aid, ABO _Three It is shown in parts by weight relative to 100 parts by weight.
[0075]
(Example 1)
ABO as main component _Three Wherein, as a compound containing A, BaCO _Three And SrCO _Three Is prepared, and TiO is used as a compound containing B. _Two Was prepared. These powders were then combined with the “ABO” in Table 1. _Three Was weighed so as to have the composition ratio shown in the column, and pure water was added, wet-mixed by a ball mill for 24 hours, and then evaporated to dryness. Next, this mixed powder is calcined at a temperature of 1100 ° C. in a natural atmosphere to form an ABO. _Three Are synthesized and pulverized to obtain the ABO according to Example 1. _Three A powder was obtained.
[0076]
On the other hand, Ho _Two O _Three And MnO _Two Are prepared, and these powders are weighed so as to have a composition ratio shown in each column of “R component” and “M component” in Table 1, wet-mixed by a ball mill, and calcined at a temperature of 1000 ° C. Then, the powder was ground to obtain a calcined powder according to Example 1.
[0077]
Next, the above-mentioned ABO _Three The powder and a part of the calcined powder were referred to as “ABO” shown in Table 1. _Three And a part of the calcined powder were weighed so as to have the composition ratios shown in the respective columns, and pure water was added thereto, wet-mixed by a ball mill for 24 hours, and then evaporated to dryness. Next, the mixed powder was calcined in a natural atmosphere at a temperature of 900 ° C. and pulverized to obtain a modified ABO according to Example 1. _Three A powder was obtained.
[0078]
Next, the above-mentioned modified ABO _Three In the powder, the remainder of the above-mentioned calcined powder was blended so as to have the composition ratio shown in the column of “Remainder of calcined powder” in Table 1, and “Other” and “Sintering aid” in Table 1 were added. MgO and BaCO 3 so that the composition ratio shown in each column _Three And B _Two O _Three −Li _Two O-SiO _Two A dielectric ceramic raw material powder according to Example 1 was obtained by mixing a BaO-based sintering aid.
[0079]
(Example 2)
ABO as main component _Three Wherein, as a compound containing A, BaCO _Three And CaCO _Three Is prepared and TiO is used as a compound containing B. _Two And HfO _Two Was prepared. These powders were then combined with “ABO” in Table 1. _Three ”, The pure water was added thereto, and the mixture was wet-mixed with a ball mill for 24 hours, and then evaporated to dryness. Next, this mixed powder is calcined at a temperature of 1100 ° C. in a natural atmosphere to obtain ABO. _Three Is synthesized and pulverized to obtain the ABO according to Example 2. _Three A powder was obtained.
[0080]
On the other hand, as an additive component, Sm _Two O _Three , Y _Two O _Three , MnO _Two And Cr _Two O _Three Are prepared, and these powders are weighed so as to have the composition ratios shown in each column of “R component” and “M component” in Table 1, wet-mixed by a ball mill, and calcined at a temperature of 1000 ° C. Then, the powder was ground to obtain a calcined powder according to Example 2.
[0081]
Next, the above-mentioned ABO _Three The powder and a part of the calcined powder were referred to as “ABO” shown in Table 1. _Three And a part of the "calcined powder" were weighed so as to have the composition ratios shown in each column, pure water was added thereto, wet-mixed by a ball mill for 24 hours, and then evaporated to dryness. Next, the mixed powder was calcined in a natural atmosphere at a temperature of 900 ° C. and pulverized to obtain a modified ABO according to Example 2. _Three A powder was obtained.
[0082]
Next, the above-mentioned modified ABO _Three The powder was blended with the remainder of the calcined powder so as to have the composition ratio shown in the column of “Remaining calcined powder” in Table 1, and “Other” and “Sintering aid” in Table 1. So that the composition ratio shown in each column _Three A sintering aid having the same composition as in Example 1 was blended to obtain a dielectric ceramic raw material powder according to Example 2.
[0083]
(Example 3)
ABO as main component _Three Wherein, as a compound containing A, BaCO _Three And CaCO _Three Is prepared and TiO is used as a compound containing B. _Two And ZrO _Two Was prepared. These powders were then combined with “ABO” in Table 1. _Three ”, The pure water was added thereto, and the mixture was wet-mixed with a ball mill for 24 hours, and then evaporated to dryness. Next, this mixed powder is calcined at a temperature of 1100 ° C. in a natural atmosphere to obtain ABO. _Three Is synthesized and pulverized to obtain an ABO according to Example 3. _Three A powder was obtained.
[0084]
On the other hand, as an additive component, Er _Two O _Three And CoO _Three Are prepared, and these powders are weighed so as to have the composition ratios shown in each column of “R component” and “M component” in Table 1, wet-mixed by a ball mill, and calcined at a temperature of 1000 ° C. Then, the mixture was ground to obtain a calcined powder according to Example 3.
[0085]
Next, the above-mentioned ABO _Three The powder and a part of the calcined powder were referred to as “ABO” shown in Table 1. _Three And a part of the calcined powder were weighed so as to have the composition ratios shown in the respective columns, and pure water was added thereto, wet-mixed by a ball mill for 24 hours, and then evaporated to dryness. Next, the mixed powder was calcined in a natural atmosphere at a temperature of 900 ° C. and pulverized to obtain a modified ABO according to Example 3. _Three A powder was obtained.
[0086]
Next, the above-mentioned modified ABO _Three The powder was blended with the remainder of the calcined powder so as to have the composition ratio shown in the column of “Remaining calcined powder” in Table 1, and “Other” and “Sintering aid” in Table 1. So that the composition ratio shown in each column of _Two O _Three And BaCO _Three Further, a sintering aid having the same composition as in Example 1 was blended to obtain a dielectric ceramic raw material powder according to Example 3.
[0087]
(Example 4)
ABO as main component _Three Wherein, as a compound containing A, BaCO _Three And CaCO _Three Is prepared and TiO is used as a compound containing B. _Two Was prepared. These powders were then combined with “ABO” in Table 1. _Three ”, The pure water was added thereto, and the mixture was wet-mixed with a ball mill for 24 hours, and then evaporated to dryness. Next, this mixed powder is calcined at a temperature of 1100 ° C. in a natural atmosphere to obtain ABO. _Three Is synthesized and pulverized to obtain the ABO according to Example 4. _Three A powder was obtained.
[0088]
On the other hand, as an additive component, La _Two O _Three , Dy _Two O _Three And Cr _Two O _Three Are prepared, and these powders are weighed so as to have the composition ratios shown in each column of “R component” and “M component” in Table 1, wet-mixed by a ball mill, and calcined at a temperature of 1000 ° C. Then, the mixture was ground to obtain a calcined powder according to Example 4.
[0089]
Next, the above-mentioned ABO _Three The powder and a part of the calcined powder were referred to as “ABO” shown in Table 1. _Three And a part of the calcined powder were weighed so as to have the composition ratios shown in the respective columns, and pure water was added thereto, wet-mixed by a ball mill for 24 hours, and then evaporated to dryness. Next, this mixed powder was calcined in a natural atmosphere at a temperature of 900 ° C. and pulverized to obtain a modified ABO according to Example 4. _Three A powder was obtained.
[0090]
Next, the above-mentioned modified ABO _Three The powder was mixed with the remainder of the above-mentioned calcined powder so as to have the composition ratio shown in the column of “Remainder of calcined powder” in Table 1, and “Other” and “Sintering aid” in Table 1. Cr so that the composition ratio shown in each column of _Two O _Three And BaCO _Three In addition, a sintering aid having the same composition as in Example 1 was blended to obtain a dielectric ceramic raw material powder according to Example 4.
[0091]
(Example 5)
ABO as main component _Three Wherein, as a compound containing A, BaCO _Three Is prepared and TiO is used as a compound containing B. _Two Was prepared. These powders were then combined with “ABO” in Table 1. _Three ”, The pure water was added thereto, and the mixture was wet-mixed with a ball mill for 24 hours, and then evaporated to dryness. Next, this mixed powder is calcined at a temperature of 1100 ° C. in a natural atmosphere to obtain ABO. _Three Is synthesized and pulverized to obtain an ABO according to Example 5. _Three A powder was obtained.
[0092]
On the other hand, Dy _Two O _Three , MnO _Two And Cr _Two O _Three Are prepared, and these powders are weighed so as to have the composition ratios shown in each column of “R component” and “M component” in Table 1, wet-mixed by a ball mill, and calcined at a temperature of 1000 ° C. Then, the resultant was ground to obtain a calcined powder according to Example 5.
[0093]
Next, the above-mentioned ABO _Three The powder and a part of the calcined powder were referred to as “ABO” shown in Table 1. _Three And a part of the calcined powder were weighed so as to have the composition ratios shown in the respective columns, and pure water was added thereto, wet-mixed by a ball mill for 24 hours, and then evaporated to dryness. Next, this mixed powder was calcined in a natural atmosphere at a temperature of 900 ° C. and pulverized to obtain a modified ABO according to Example 5. _Three A powder was obtained.
[0094]
Next, the above-mentioned modified ABO _Three The powder was blended with the remainder of the calcined powder so as to have the composition ratio shown in the column of “Remaining calcined powder” in Table 1, and “Other” and “Sintering aid” in Table 1. So that the composition ratio shown in each column _Two O _Three And BaCO _Three In addition, a sintering aid having the same composition as in Example 1 was blended to obtain a dielectric ceramic raw material powder according to Example 5.
[0095]
(Example 6)
ABO as main component _Three Wherein, as a compound containing A, BaCO _Three , CaCO _Three And SrCO _Three Is prepared and TiO is used as a compound containing B. _Two Was prepared. These powders were then combined with “ABO” in Table 1. _Three ”, The pure water was added thereto, and the mixture was wet-mixed with a ball mill for 24 hours, and then evaporated to dryness. Next, this mixed powder is calcined at a temperature of 1100 ° C. in a natural atmosphere to obtain ABO. _Three Is synthesized and pulverized to obtain an ABO according to Example 6. _Three A powder was obtained.
[0096]
On the other hand, as an additive component, Y _Two O _Three , Yb _Two O _Three , CoO and Fe _Two O _Three Are prepared, and these powders are weighed so as to have the composition ratios shown in each column of “R component” and “M component” in Table 1, wet-mixed by a ball mill, and calcined at a temperature of 1000 ° C. Then, the resultant was ground to obtain a calcined powder according to Example 6.
[0097]
Next, the above-mentioned ABO _Three The powder and a part of the calcined powder were referred to as “ABO” shown in Table 1. _Three And a part of the calcined powder were weighed so as to have the composition ratios shown in the respective columns, and pure water was added thereto, wet-mixed by a ball mill for 24 hours, and then evaporated to dryness. Next, this mixed powder was calcined in a natural atmosphere at a temperature of 900 ° C. and pulverized to obtain a modified ABO according to Example 6. _Three A powder was obtained.
[0098]
Next, the above-mentioned modified ABO _Three The powder was blended with the remainder of the calcined powder so as to have the composition ratio shown in the column of “Remaining calcined powder” in Table 1, and “Other” and “Sintering aid” in Table 1. So that the composition ratio shown in each column _Three A sintering aid having the same composition as in Example 1 was blended to obtain a dielectric ceramic raw material powder according to Example 6.
[0099]
(Example 7)
ABO as main component _Three Wherein, as a compound containing A, BaCO _Three Is prepared and TiO is used as a compound containing B. _Two , ZrO _Two And HfO _Two Was prepared. These powders were then combined with “ABO” in Table 1. _Three ”, The pure water was added thereto, and the mixture was wet-mixed with a ball mill for 24 hours, and then evaporated to dryness. Next, this mixed powder is calcined at a temperature of 1100 ° C. in a natural atmosphere to obtain ABO. _Three Is synthesized and pulverized to obtain an ABO according to Example 7. _Three A powder was obtained.
[0100]
On the other hand, as an additive component, Gd _Two O _Three And MnO _Two Are prepared, and these powders are weighed so as to have the composition ratios shown in each column of “R component” and “M component” in Table 1, wet-mixed by a ball mill, and calcined at a temperature of 1000 ° C. Then, the resultant was ground to obtain a calcined powder according to Example 7.
[0101]
Next, the above-mentioned ABO _Three The powder and a part of the calcined powder were referred to as “ABO” shown in Table 1. _Three And a part of the calcined powder were weighed so as to have the composition ratios shown in the respective columns, and pure water was added thereto, wet-mixed by a ball mill for 24 hours, and then evaporated to dryness. Next, this mixed powder was calcined in a natural atmosphere at a temperature of 900 ° C. and pulverized to obtain a modified ABO according to Example 7. _Three A powder was obtained.
[0102]
Next, the above-mentioned modified ABO _Three In the powder, the remainder of the above-mentioned calcined powder was blended so as to have the composition ratio shown in the column of “Remainder of calcined powder” in Table 1, and “Other” and “Sintering aid” in Table 1 were added. MgO and BaCO 3 so that the composition ratio shown in each column _Three In addition, a sintering aid having the same composition as in Example 1 was blended to obtain a dielectric ceramic raw material powder according to Example 7.
[0103]
(Comparative Example 1)
In Comparative Example 1, a raw material powder of a dielectric ceramic having the same composition as in Example 1 was produced by a method different from that in Example 1.
[0104]
First, “ABO” in Table 2 was prepared using the same composition and the same method as in Example 1. _Three ", The ABO according to Comparative Example 1 _Three A powder was obtained.
[0105]
Next, Ho as an additive component _Two O _Three Was prepared, and this powder was weighed so as to have the composition ratio shown in the “R component” column in “part of the calcined powder” in Table 2, and this was weighed into the above-mentioned ABO. _Three Pure water was added to the powder, and the mixture was wet-mixed with a ball mill for 24 hours and then evaporated to dryness. Next, the mixed powder was calcined in a natural atmosphere at a temperature of 900 ° C. and pulverized, thereby obtaining the modified ABO according to Comparative Example 1. _Three A powder was obtained.
[0106]
Next, the above-mentioned modified ABO _Three The powder was added with the composition ratio shown in the column of “R component” in “Remainder of calcined powder” in Table 2 to obtain Ho. _Two O _Three And MnO 2 so that the composition ratio shown in each column of “Others” and “Sintering aid” in Table 2 is obtained. _Two , MgO and BaCO _Three In addition, a sintering aid having the same composition as in Example 1 was blended to obtain a dielectric ceramic raw material powder according to Comparative Example 1.
[0107]
(Comparative Example 2)
In Comparative Example 2, a raw material powder of a dielectric ceramic having the same composition as in Example 2 was produced by a method different from that in Example 2.
[0108]
First, “ABO” in Table 2 was prepared using the same composition and the same method as in Example 2. _Three ", The ABO according to Comparative Example 2 _Three A powder was obtained.
[0109]
Next, MnO as an additive component _Two And Cr _Two O _Three Are prepared, and these powders are weighed so as to have a composition ratio shown in the column of "M component" in Table 2, wet-mixed by a ball mill, calcined at a temperature of 1000 ° C, and then pulverized. Thus, a calcined powder according to Comparative Example 2 was obtained.
[0110]
Next, the above-mentioned ABO _Three The powder and a part of the calcined powder were referred to as “ABO” shown in Table 2. _Three And a part of the calcined powder were weighed so as to have the composition ratios shown in the respective columns, and pure water was added thereto, wet-mixed by a ball mill for 24 hours, and then evaporated to dryness. Next, this mixed powder was calcined in a natural atmosphere at a temperature of 900 ° C. and pulverized to obtain a modified ABO according to Comparative Example 2. _Three A powder was obtained.
[0111]
Next, the above-mentioned modified ABO _Three To the powder, the remainder of the above-mentioned calcined powder was blended so as to have the composition ratio shown in the column of “Remainder of calcined powder” in Table 2, and “Other” and “Sintering aid” in Table 2 were added. Sm so that the composition ratio shown in each column of _Two O _Three , Y _Two O _Three And BaCO _Three In addition, a sintering aid having the same composition as in Example 1 was blended to obtain a dielectric ceramic raw material powder according to Comparative Example 2.
[0112]
(Comparative Example 3)
In Comparative Example 3, first, “ABO” in Table 2 was prepared using the same composition and the same method as in Example 3. _Three , The ABO according to Comparative Example 3 _Three A powder was obtained.
[0113]
Next, Er as an additive component _Two O _Three And CoO were prepared, and these powders were weighed so as to have the composition ratios shown in the respective columns of “R component” and “M component” in Table 2, and wet-mixed with a ball mill. By calcining and then pulverizing, a calcined powder according to Comparative Example 3 was obtained. Here, Er as the “R component” _Two O _Three Should be noted that the ratio is smaller than that of CoO, which is the “M component”.
[0114]
Next, the above-mentioned ABO _Three The powder and a part of the calcined powder were referred to as “ABO” shown in Table 2. _Three And a part of the calcined powder were weighed so as to have the composition ratios shown in the respective columns, and pure water was added thereto, wet-mixed by a ball mill for 24 hours, and then evaporated to dryness. Next, this mixed powder was calcined in a natural atmosphere at a temperature of 900 ° C. and pulverized to obtain a modified ABO according to Comparative Example 3. _Three A powder was obtained.
[0115]
Next, the above-mentioned modified ABO _Three To the powder, the remainder of the above-mentioned calcined powder was blended so as to have the composition ratio shown in the column of “Remainder of calcined powder” in Table 2, and “Other” and “Sintering aid” in Table 2 were added. Er so that the composition ratio shown in each column of _Two O _Three , Al _Two O _Three And BaCO _Three Further, a sintering aid having the same composition as in Example 1 was blended to obtain a dielectric ceramic raw material powder according to Comparative Example 3.
[0116]
(Comparative Example 4)
In Comparative Example 4, first, “ABO” in Table 2 was prepared using the same composition and the same method as in Example 4. _Three ", The ABO according to Comparative Example 4 _Three A powder was obtained.
[0117]
Next, the above-mentioned ABO _Three La as an additive component was added to the powder so as to have the composition ratio shown in each column of “Other” and “Sintering aid” in Table 2. _Two O _Three , Cr _Two O _Three And BaCO _Three In addition, a sintering aid having the same composition as in Example 1 was blended to obtain a dielectric ceramic raw material powder according to Comparative Example 4.
[0118]
(Comparative Example 5)
In Comparative Example 5, first, “ABO” in Table 2 was prepared using the same composition and the same method as in Example 5. _Three , The ABO according to Comparative Example 5 _Three A powder was obtained.
[0119]
On the other hand, as in the case of Example 5, Dy was used as an additional component. _Two O _Three , MnO _Two And Cr _Two O _Three Were prepared, and these powders were weighed so as to have the composition ratios shown in the respective columns of “R component” and “M component” in Table 2, wet-mixed with a ball mill, and calcined at a temperature of 1000 ° C. Then, the resultant was ground to obtain a calcined powder according to Comparative Example 5. Here, Dy that is the “R component” _Two O _Three Is the “M component” MnO _Two And Cr _Two O _Three It should be noted that the ratio is smaller.
[0120]
Next, the above-mentioned ABO _Three The powder and a part of the calcined powder were referred to as “ABO” shown in Table 2. _Three And a part of the calcined powder were weighed so as to have the composition ratios shown in the respective columns, and pure water was added thereto, wet-mixed by a ball mill for 24 hours, and then evaporated to dryness. Next, the mixed powder was calcined in a natural atmosphere at a temperature of 900 ° C. and pulverized to obtain a modified ABO according to Comparative Example 5. _Three A powder was obtained.
[0121]
Next, the above-mentioned modified ABO _Three To the powder, the remainder of the above-mentioned calcined powder was blended so as to have the composition ratio shown in the column of “Remainder of calcined powder” in Table 2, and “Other” and “Sintering aid” in Table 2 were added. So that the composition ratio shown in each column _Two O _Three And BaCO _Three Further, a sintering aid having the same composition as in Example 1 was blended to obtain a dielectric ceramic raw material powder according to Comparative Example 5.
[0122]
(Comparative Example 6)
In Comparative Example 6, first, the “ABO” _Three , The ABO according to Comparative Example 6 _Three A powder was obtained.
[0123]
On the other hand, as in the case of Comparative Example 5, Dy _Two O _Three , MnO _Two And Cr _Two O _Three Were prepared, and these powders were weighed so as to have the composition ratios shown in the respective columns of “R component” and “M component” in Table 2, wet-mixed with a ball mill, and calcined at a temperature of 1000 ° C. Then, the mixture was ground to obtain a calcined powder according to Comparative Example 6. Here, the calcined powder according to Comparative Example 6 has the same composition as the calcined powder according to Comparative Example 5, and Dy that is the “R component” _Two O _Three Is the “M component” MnO _Two And Cr _Two O _Three It should be noted that the ratio is smaller.
[0124]
Next, the above-mentioned ABO _Three In the powder, all of the above-mentioned calcined powder were blended so as to have the composition ratio shown in the column of “Remaining calcined powder” in Table 2, and “Other” and “Sintering aid” in Table 2 were added. So that the composition ratio shown in each column _Two O _Three And BaCO _Three Further, a sintering aid having the same composition as in Example 1 was blended to obtain a dielectric ceramic raw material powder according to Comparative Example 6.
[0125]
2. Fabrication of multilayer ceramic capacitors
Next, an organic solvent such as a polyvinyl butyral-based binder and ethanol is added to the dielectric ceramic raw material powder according to each of Examples 1 to 7 and Comparative Examples 1 to 6, and wet mixing is performed using a ball mill. Thus, a ceramic slurry was prepared.
[0126]
Next, the ceramic slurry was formed into a sheet by a doctor blade method with a thickness such that the thickness of the fired dielectric ceramic layer became 3 μm, to obtain a rectangular ceramic green sheet.
[0127]
Next, a conductive paste mainly composed of nickel was screen-printed on the ceramic green sheet to form a conductive paste film to be an internal electrode.
[0128]
Next, a plurality of ceramic green sheets including a ceramic green sheet on which the conductive paste film was formed were laminated so that the side from which the conductive paste film was drawn out was alternated, to obtain a raw laminate.
[0129]
Next, the green laminate is heated to a temperature of 350 ° C. in a nitrogen atmosphere, and the binder is burned. ^-9 -10 ^-12 H of MPa _Two -N _Two -H _Two In a reducing atmosphere composed of O gas, firing was performed at a firing temperature shown in Table 3 below for 2 hours to obtain a sintered laminate.
[0130]
Next, on both end surfaces of the laminate, B _Two O _Three −Li _Two O-SiO _Two A conductive paste containing a BaO-based glass frit and containing silver as a conductive component was applied and baked at a temperature of 800 ° C. in a nitrogen atmosphere to form external electrodes electrically connected to the internal electrodes.
[0131]
The external dimensions of the multilayer ceramic capacitor thus obtained are 1.6 mm in width, 3.2 mm in length, and 1.2 mm in thickness, and the thickness of the dielectric ceramic layer interposed between the internal electrodes is 3 μm. there were. The number of effective dielectric ceramic layers is 100, and the area of the counter electrode per layer is 2.1 mm. ^Two Met.
[0132]
3. Measurement of electrical characteristics
Various electrical characteristics of the multilayer ceramic capacitors according to Examples 1 to 7 and Comparative Examples 1 to 6 thus obtained were measured.
[0133]
First, the dielectric constant ε and the insulation resistance of each multilayer ceramic capacitor at room temperature were measured. In this case, the dielectric constant ε is a temperature of 25 ° C., 1 kHz, and 1 V _rms Was measured under the following conditions. In order to measure the insulation resistance under an electric field strength of 5 kV / mm, a DC voltage of 15 V was applied for 2 minutes, the insulation resistance was measured at + 25 ° C., and the capacitance (C) and the insulation resistance (R) were measured. , Ie, the CR product.
[0134]
Further, the change rate of the capacitance with respect to the temperature change was obtained. Regarding the rate of change of the capacitance with respect to the temperature change, the rate of change at −25 ° C. and the rate of change at 85 ° C. (ΔC / C) based on the B characteristic of the JIS standard, that is, the capacitance at 20 ° C. ₂₀ ) And the rate of change at −55 ° C. and the rate of change at 125 ° C. (ΔC / C) based on the X7R characteristic of the EIA standard, that is, the capacitance at 25 ° C. _{twenty five} ) And evaluated.
[0135]
In addition, a high temperature load life test was performed. In the high-temperature load life test, a voltage of 60 V was applied to 36 samples at a temperature of 150 ° C. so that the electric field strength became 20 kV / mm, and the change with time of the insulation resistance was determined. As the high-temperature load life, the average life time was determined by setting the time when the insulation resistance value of each sample became 200 kΩ or less as the life time.
[0136]
Further, the change with time of the capacitance under application of a DC voltage was determined. The change with time of the capacitance is as follows: temperature 85 ° C, 1kHz, 1V _rms , And a change in capacitance after a lapse of 100 hours under the conditions of application of a DC voltage of 3.15 V, and a DC load change with time was determined based on the capacitance at 85 ° C. immediately after the application of the DC voltage.
[0137]
The above dielectric constant ε, CR product, temperature characteristic (ΔC / C ₂₀ And ΔC / C _{twenty five} ), The average life time and the change over time of the capacitance are shown in Table 3.
[0138]
[Table 3]

[0139]
4. Investigation of microstructure
With respect to the multilayer ceramic capacitors according to Examples 1 to 7 and Comparative Examples 1 to 6, the microstructure of the dielectric ceramic constituting the dielectric ceramic layer was investigated. More specifically, the following survey was conducted.
[0140]
First, a multilayer ceramic capacitor as a sample was polished at right angles to the surface on which the internal electrodes extend to expose the dielectric ceramic layer. Next, by an energy dispersive X-ray spectroscopy (EDX) using a transmission electron microscope, as shown in FIG. The R and M concentration analysis were performed at each of the analysis points 23 located in a region up to 5% from the surface (region near the surface) and the analysis points 24 located in the crystal grain boundaries 22. Note that a 2 nm probe was used as an electron beam for analysis.
[0141]
Here, as for the region near the surface of the crystal particle 21 and the crystal grain boundary 22, more specifically, five or more crystal particles 21 are randomly selected, and the outer periphery of each selected crystal particle 21 is substantially Arbitrary four points, which are divided into four, were designated as analysis points 23 and 24, respectively. In the analysis of the crystal grain boundaries 22, there are cases where selection is made from a region formed by two crystal grains 21 and cases where selection is made from a region formed by three or more crystal grains 21. Further, the analysis at the crystal grain boundaries 22 formed between the same crystal grains 21 is avoided.
[0142]
As a result of such analysis, the concentration of R _R And the concentration of M is C _M With respect to the analysis point located near the surface of the crystal particle, _R / C _M The ratio of analysis points satisfying the condition of> 1 was calculated. The results are shown in the column of “Surface near surface concentration condition satisfaction ratio” in Table 4.
[0143]
Further, regarding the analysis point located at the crystal grain boundary, C _R / C _M The ratio of analysis points satisfying the condition of> 1 was calculated. The results are shown in the column of “Grain boundary density condition satisfaction ratio” in Table 4.
[0144]
Also, C at the center of the crystal grain _R And C _M , Respectively, in the region near the surface of the crystal grain. _R And C _M The ratio of the number of crystal grains that satisfies the condition of being 1/10 or less of each maximum value was calculated. The results are shown in the column of “central part density condition satisfaction ratio” in Table 4.
[0145]
The surface of the multilayer ceramic capacitor as a sample, which was broken and thermally etched, was photographed using a scanning electron microscope, and the particle size of the crystal particles was determined from the obtained photograph. Then, 10 or more crystal grains were randomly selected, and the average value of the particle diameters was determined to be the average particle diameter. The results are shown in Table 4 in the column of “average particle size of crystal particles”.
[0146]
[Table 4]

[0147]
5. Comprehensive evaluation
First, a comparison is made between Example 1 and Comparative Example 1.
[0148]
In Example 1, as shown in Table 4, the “satisfaction ratio near surface density condition” was 89%, the “grain boundary density condition satisfaction ratio” was 95%, and the “central density condition satisfaction ratio” was 95%. 73%. On the other hand, in Comparative Example 1, the “satisfaction ratio near the surface density condition” is 86%, but the “grain boundary density condition satisfaction ratio” is only 45%, and the “central density condition satisfaction ratio” is 53%. .
[0149]
As a result, in Example 1 and Comparative Example 1, as shown in Table 3, the values of the dielectric constant and the CR product were almost the same, that is, both values were a dielectric constant of 2700 and a CR product of about 3000. showed that.
[0150]
However, with respect to the temperature characteristics, Example 1 satisfies the X7R characteristics of the EIA standard, while Comparative Example 1 does not satisfy this characteristic. In addition, the average life time is as long as 214 hours in Example 1, which indicates high reliability, whereas the average life time is as short as 36 hours in Comparative Example 1, and sufficient reliability is not obtained. Also, with respect to the change with time of the capacitance, in Example 1, a favorable result was obtained, such as -4.5%, as compared with -16.3% in Comparative Example 1.
[0151]
In Examples 2 to 7, as in Example 1, excellent results were obtained.
[0152]
That is, in Examples 2 to 7, as shown in Table 4, the “satisfaction ratios near the surface concentration condition” are each 60% or more, and the “grain boundary concentration condition satisfaction ratios” are each 60% or more. The “central density condition satisfaction ratio” is 50% or more.
[0153]
As a result, as shown in Table 3, in all of Examples 2 to 7, the temperature characteristics satisfy the X7R characteristics of the EIA standard, the CR product is high, the average life time is long, and therefore, the reliability is excellent. The change over time of the capacitance is also small.
[0154]
On the other hand, in Comparative Example 2, as shown in Table 4, the “satisfaction ratio of near surface density condition” was 33%, the “grain boundary density condition satisfaction ratio” was 84%, and the “central portion density condition satisfaction ratio” was 84%. The “satisfaction ratio” is 68%. As a result, in Comparative Example 2, as shown in Table 3, the average life time was as short as 20 hours, sufficient reliability was not obtained, and the change with time of the capacitance was −14.1%. Indicates the value.
[0155]
In Comparative Example 3, as shown in Table 4, the “satisfaction ratio near the surface density condition” is 56%, the “grain boundary density condition satisfaction ratio” is 93%, and the “central density condition satisfaction ratio” is 75%. %. As a result, in Comparative Example 3, as shown in Table 3, the average life time was as short as 67 hours, sufficient reliability was not obtained, and the change with time of the capacitance was -12.3%. Indicates the value.
[0156]
In Comparative Example 4, as shown in Table 4, the “satisfaction ratio near surface density condition” is 62%, the “grain boundary density condition satisfaction ratio” is 58%, and the “central density condition satisfaction ratio” is 30%. %. As a result, in Comparative Example 4, as shown in Table 3, the average life time was as short as 6 hours, sufficient reliability was not obtained, and the change with time of the capacitance was -19.1%, which was a large absolute value. The temperature characteristics do not satisfy the X7R characteristics of the EIA standard.
[0157]
In Comparative Example 5, as shown in Table 4, the “satisfaction ratio near surface density condition” was 45%, the “grain boundary density condition satisfaction ratio” was 80%, and the “central density condition satisfaction ratio” was 84%. %. As a result, in Comparative Example 5, as shown in Table 3, the average life time was as short as 33 hours, sufficient reliability was not obtained, and the change over time of the capacitance was -15.0%, which was large. Indicates the value.
[0158]
In Comparative Example 6, as shown in Table 4, the “satisfaction ratio of near-surface density condition” was 53%, the “grain boundary density condition satisfaction ratio” was 72%, and the “central density condition satisfaction ratio” was 70%. %. As a result, in Comparative Example 6, as shown in Table 3, the average life time was as short as 45 hours, sufficient reliability was not obtained, and the change with time of the capacitance was -13.8%, which was large. Indicates the value.
[0159]
【The invention's effect】
As described above, according to the dielectric ceramic according to the present invention, ABO _Three (A is Ba or at least one of Ba and partially substituted Ca and Sr, and B is Ti or at least one of Ti and partially substituted Zr and Hf. .) And at least one of R, R, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y And M (where M is at least one of Mn, Co, Fe and Cr), and ABO. _Three Is composed of crystal grains mainly composed of _R And the concentration of M is C _M As for the analysis points located in the region up to 5% from the surface (the region near the surface) and the plurality of analysis points located in the crystal grain boundaries with respect to the diameter of the crystal particles, the analysis points , C _R / C _M Since the condition of &gt; 1 is satisfied, when a multilayer ceramic capacitor is formed using the same, the change in the dielectric constant with temperature and the change with time in the capacitance under the application of a DC voltage are small. The product (CR product) is high, and the accelerated life of insulation resistance at high temperature and high voltage can be extended.
[0160]
Therefore, if the dielectric ceramic layer of the multilayer ceramic capacitor is formed using the dielectric ceramic, a multilayer ceramic capacitor that can maintain excellent reliability even when the thickness of the dielectric ceramic layer is reduced can be obtained.
[0161]
Therefore, by making the dielectric ceramic layer thinner, the multilayer ceramic capacitor can be made smaller and larger in capacity, and even when the dielectric ceramic layer is made thinner, there is no need to lower the rated voltage of the multilayer ceramic capacitor. . As a result, for example, the thickness of the dielectric ceramic layer can be reduced to about 3 μm without any problem.
[0162]
In the dielectric ceramic according to the present invention, C at the analysis point in the center of the crystal grain _R And C _M Are C at the analysis point in the region near the surface of the crystal particle, respectively. _R And C _M If the ratio of the number of crystal grains, which is 1/10 or less of each maximum value, is set to 50% or more, it is possible to surely prevent the deterioration of the temperature characteristics and the decrease in reliability due to the grain growth. can do.
[0163]
Further, the dielectric ceramic according to the present invention may be provided with SiO 2 _Two , Li _Two O and B _Two O _Three When a sintering aid containing at least one selected from the group consisting of (boron oxide) as a main component is contained, the sintering temperature of the dielectric ceramic can be lowered, or the CR product or the insulation resistance under high temperature and high voltage can be accelerated. The service life can be further improved.
[0164]
Further, when the average particle diameter of the crystal grains constituting the dielectric ceramic according to the present invention is set to 0.5 μm or less, it is possible to appropriately cope with the reduction of the thickness of the dielectric ceramic layer provided in the multilayer ceramic capacitor. Become like
[0165]
On the other hand, according to the method for manufacturing a dielectric ceramic according to the present invention, the above-described ABO _Three By synthesizing and then grinding _Three A step of obtaining a powder, a step of preparing the above-described R compound containing R, a step of preparing the above-described M compound containing M, and mixing the R compound and the M compound so that the ratio of the R compound is increased. Calcining the resulting mixture and then pulverizing to obtain a calcined powder; _Three The powder is mixed with a part of the calcined powder, and the resulting mixture is calcined and then pulverized to obtain a modified ABO. _Three Step of obtaining powder, modified ABO _Three A step of firing a mixed powder containing the powder and the remainder of the calcined powder, so that a dielectric ceramic satisfying the above concentration conditions can be easily and reliably manufactured.
[Brief description of the drawings]
FIG. 1 is a sectional view schematically showing a multilayer ceramic capacitor 1 according to an embodiment of the present invention.
FIG. 2 shows ABO constituting a dielectric ceramic _Three FIG. 2 is a cross-sectional view schematically showing a crystal grain 21 occupying the main component and a crystal grain boundary 22 occupying the space between the crystal grains 21, and an analysis point 23 located in a region near the surface of the crystal grain 21 and a crystal grain boundary 22. Each example of the analysis point 24 and the analysis point 25 located at the center of the crystal particle 21 is shown.
[Explanation of symbols]
1 multilayer ceramic capacitor
2 laminate
3 dielectric ceramic layer
4,5 internal electrode
8, 9 external electrode
21 Crystal particles
22 Grain boundary
23 Analysis points located in the area near the surface of crystal grains
24 Analysis points located at grain boundaries
25 Analysis point located at the center of the crystal grain

Claims (8)

ABO ₃ (A is Ba or at least one of Ba and partially substituted Ca and Sr, and B is Ti or at least one of Ti and partially substituted Zr and Hf thereof. And R (R is at least one of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and Y). And M (M is at least one of Mn, Co, Fe and Cr), and an additive component containing ABO ₃ as a main component. And crystal grain boundaries occupying between crystal grains,
Assuming that the concentration of _R is C _R and the concentration of _M is C _M , analysis points located in a region up to 5% from the surface with respect to the diameter of the crystal grains and a plurality of analysis points located at the crystal grain boundary are: A dielectric ceramic which satisfies the condition of C _R / C _M > 1 at each of 60% or more analysis points. For 50% or more of the crystal grains, C _R and C _M in the central part of the crystal grains are respectively C _R and C _M in a region from the surface to 5% with respect to the diameter of the crystal grains. 2. The dielectric ceramic according to claim 1, which satisfies a condition of being 1/10 or less of each of the maximum values. The dielectric ceramic according to claim 1, further comprising a sintering aid containing at least one selected from the group consisting of SiO ₂ , Li ₂ O, and B ₂ O ₃ (boron oxide). The dielectric ceramic according to any one of claims 1 to 3, wherein the average diameter of the crystal grains is 0.5 µm or less. ABO ₃ (A is Ba or at least one of Ba and partially substituted Ca and Sr, and B is Ti or at least one of Ti and partially substituted Zr and Hf thereof. A) obtaining ABO ₃ powder by synthesizing and then grinding;
An R compound containing R (R is at least one of La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y) is prepared. The process of
Preparing an M compound containing M (M is at least one of Mn, Co, Fe and Cr);
Mixing the R compound and the M compound so that the ratio of the R compound increases, calcining the resulting mixture, and then pulverizing to obtain a calcined powder;
Mixing the ABO ₃ powder and a portion of the calcined powder, calcining the resulting mixture, and then pulverizing to obtain a modified ABO ₃ powder;
Baking a mixed powder containing the modified ABO ₃ powder and the remainder of the calcined powder. A stacked body including a plurality of stacked dielectric ceramic layers and a plurality of internal electrodes formed along a specific interface between the plurality of dielectric ceramic layers and overlapping in a stacking direction; and specifying the internal electrodes. An external electrode formed on an outer surface of the multilayer body so as to be electrically connected to the multilayer ceramic capacitor,
A multilayer ceramic capacitor, wherein the dielectric ceramic layer is made of the dielectric ceramic according to any one of claims 1 to 4. The multilayer ceramic capacitor according to claim 6, wherein the internal electrode includes a base metal. The multilayer ceramic capacitor according to claim 6, wherein the external electrode includes a base metal.

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