JP2775916B2 - Multilayer ceramic capacitors - Google Patents
Multilayer ceramic capacitorsInfo
- Publication number
- JP2775916B2 JP2775916B2 JP29020289A JP29020289A JP2775916B2 JP 2775916 B2 JP2775916 B2 JP 2775916B2 JP 29020289 A JP29020289 A JP 29020289A JP 29020289 A JP29020289 A JP 29020289A JP 2775916 B2 JP2775916 B2 JP 2775916B2
- Authority
- JP
- Japan
- Prior art keywords
- ceramic dielectric
- capacitor
- dielectric layer
- ceramic
- copper powder
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Landscapes
- Ceramic Capacitors (AREA)
- Fixed Capacitors And Capacitor Manufacturing Machines (AREA)
Description
【発明の詳細な説明】 産業上の利用分野 この発明は、電子機器の回路部品等に使える積層セラ
ミックンコンデンサに関する。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer ceramic capacitor that can be used as a circuit component of an electronic device.
従来の技術 この積層セラミックコンデンサは、セラミック誘電体
層と内部電極層が交互に積層され焼結された多層構造を
とる容量素子であり、セラミック誘電体層としては、普
通、ペロブスカイト系結晶構造有するもの（例えば、Ba
TiO3）が使われる。焼結は、空気雰囲気中、1300〜1350
℃程度の高温焼成によりなされる。2. Description of the Related Art A multilayer ceramic capacitor is a capacitive element having a multilayer structure in which ceramic dielectric layers and internal electrode layers are alternately laminated and sintered, and the ceramic dielectric layer usually has a perovskite crystal structure. (For example, Ba
TiO 3 ) is used. Sintering is in air atmosphere, 1300-1350
It is performed by firing at a high temperature of about ° C.
発明が解決しようとする課題 しかしながら、このような高温での焼成が必要な場
合、Ni、Cu等の安価な金属材料は、酸化してしまうので
内部電極用材料に使うことができず、高価なPdを使うこ
とになる。このように、高価なPdを使うので、従来の積
層セラミックコンデンサは、どうしても高価なものにな
る。However, when firing at such a high temperature is necessary, inexpensive metal materials such as Ni and Cu are oxidized and thus cannot be used as a material for internal electrodes. You will use Pd. As described above, since expensive Pd is used, the conventional multilayer ceramic capacitor is necessarily expensive.
積層セラミックコンデンサのコストダウンを図るた
め、セラミック誘電体層に鉛系セラミック誘電体を使い
低温焼成化を図ることも検討されている。しかしなが
ら、この場合には、誘電体にPbOが存在することから、
セラミック誘電体層が脆く欠け易くて十分な機械的強度
がなく、しかも、誘電体層と内部電極層の界面における
イオンの相互拡散の幅が広くて損失が大きくなるなどコ
ンデンサ特性も十分でないという問題がある。In order to reduce the cost of the multilayer ceramic capacitor, it has been studied to use a lead-based ceramic dielectric for the ceramic dielectric layer to achieve low-temperature firing. However, in this case, since PbO exists in the dielectric,
The problem is that the ceramic dielectric layer is brittle and easily chipped, does not have sufficient mechanical strength, and the characteristics of the capacitor are not sufficient such as wide inter-diffusion of ions at the interface between the dielectric layer and the internal electrode layer resulting in large loss. There is.
この発明は、上記事情に鑑み、1100℃程度の低温で十
分に焼結が可能で内部電極層とセラミック誘電体層間の
界面状態が良好であって、しかも、低温焼結であっても
内部電極層とセラミック誘電体層の接合は強固であり、
かつ、コストダウンが可能な積層セラミックコンデンサ
を提供することを課題とする。In view of the above circumstances, the present invention is capable of sufficiently sintering at a low temperature of about 1100 ° C., has a good interface state between the internal electrode layer and the ceramic dielectric layer, and furthermore has an internal electrode The bond between the layers and the ceramic dielectric layer is strong,
It is another object of the present invention to provide a multilayer ceramic capacitor capable of reducing costs.
課題を解決するための手段 上記課題を解決するため、この発明の積層セラミック
コンデンサは、セラミック誘電体層と内部電極層が積層
焼結されてなり、前記セラミック誘電体層が焼結助剤と
して金属銅粉末を0.1〜5.0wt％含んで焼結されてなる構
成となっている。Means for Solving the Problems To solve the above problems, a multilayer ceramic capacitor according to the present invention comprises a ceramic dielectric layer and an internal electrode layer laminated and sintered, and the ceramic dielectric layer is made of metal as a sintering aid. It is configured to be sintered containing 0.1 to 5.0 wt% of copper powder.
作用 この発明のコンデンサでは、セラミック誘電体原料に
金属銅粉末が添加されていて、焼成の際、溶融温度の低
い（融点1086℃）金属銅粒子が誘電体原料の粒子間に入
り一時的なフラックス作用を起こすため、セラミック誘
電体原料の一部が溶融し低温で十分に焼結するようにな
る。金属銅粒子は焼成により酸化物となるため、誘電体
の絶縁性を劣化させる心配はない。In the capacitor of the present invention, metallic copper powder is added to the ceramic dielectric material, and during firing, metal copper particles having a low melting temperature (melting point 1086 ° C.) enter between the particles of the dielectric material and temporarily cause a flux. Due to the action, a part of the ceramic dielectric material is melted and sufficiently sintered at a low temperature. Since the metallic copper particles become oxides by firing, there is no need to worry about deterioration of the insulating properties of the dielectric.
低い温度で焼成するため、セラミック誘電体層と内部
電極層の間の界面における拡散層の幅が狭く、低損失特
性のコンデンサになる。Since firing is performed at a low temperature, the width of the diffusion layer at the interface between the ceramic dielectric layer and the internal electrode layer is small, and the capacitor has low loss characteristics.
セラミック誘電体層がBaTiO3を主成分とする場合に
は、誘電体層自体の機械的強度が十分であり、製造時の
歩留まりも良い。When the ceramic dielectric layer contains BaTiO 3 as a main component, the mechanical strength of the dielectric layer itself is sufficient, and the production yield is good.
実施例 以下に本発明の実施例を図面を用いて詳細に説明す
る。第１図に本発明の一実施例における積層セラミック
コンデンサの層構成を示す。Embodiment An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a layer structure of a multilayer ceramic capacitor according to an embodiment of the present invention.
コンデンサはセラミック誘電体層１と内部電極層２が
交互に積層され両層が共焼結されてなる積層体を備える
とともに、同積層体の側面に設けられた接続電極３、３
を備えている。各内部電極２…は、第１図にみるよう
に、下から１番目、３番目が右側の接続電極３へ、２番
目、４番目が左側の接続電極３へそれぞれ接続されてい
て、隣り合う内部電極層２の間に容量を持たせる構成に
なっている。The capacitor includes a laminate in which ceramic dielectric layers 1 and internal electrode layers 2 are alternately laminated and both layers are co-sintered, and connection electrodes 3, 3 provided on side surfaces of the laminate.
It has. As shown in FIG. 1, the first and third internal electrodes 2 are connected to the right connection electrode 3, and the second and fourth internal electrodes 2 are connected to the left connection electrode 3. The structure is such that a capacitance is provided between the internal electrode layers 2.
この発明のコンデンサのセラミック誘電体層１として
は、BaTiO3等のようにペロブスカイト結晶構造を有する
セラミック誘電体が用いられる。As the ceramic dielectric layer 1 of the capacitor of the present invention, a ceramic dielectric having a perovskite crystal structure such as BaTiO 3 is used.
また、この発明のコンデンサの内部電極層２として
は、卑金属、誘電性酸化物など安価な材料が使用可能で
ある。Further, as the internal electrode layer 2 of the capacitor of the present invention, inexpensive materials such as base metals and dielectric oxides can be used.
焼結助剤としての金属銅粉末の使用量は、誘電体層用
セラミック原料100wt％に対して、0.1〜5.0wt％の範囲
である。0.1wt％未満では金属銅粉末の添加効果が十分
にあらわれない。5.0wt％を上回ると誘電体の誘電率が
小さくなるという悪影響が顕著となる。The amount of metallic copper powder used as a sintering aid is in the range of 0.1 to 5.0 wt% with respect to 100 wt% of the ceramic material for the dielectric layer. If it is less than 0.1 wt%, the effect of adding the metallic copper powder is not sufficiently exhibited. If it exceeds 5.0 wt%, the adverse effect that the dielectric constant of the dielectric material becomes small becomes significant.
普通、金属銅粉末をセラミック誘電体原料粉末に加え
混合するが、金属銅粉末粒子のサイズがセラミック誘電
体原料粉末粒子サイズより小さい場合には、均一に混合
させやすくなる。Normally, copper metal powder is added to and mixed with the ceramic dielectric raw material powder, but when the size of the metal copper powder particles is smaller than the ceramic dielectric raw material powder particle size, uniform mixing is facilitated.
この発明のコンデンサは、上記図示の層構成や化合物
に限らないことは言うまでもない。It goes without saying that the capacitor of the present invention is not limited to the above-described layer configuration and compound.
低温焼成は、内部電極用材料に安価な卑金属や誘電性
酸化物の使用を可能にするため、コストダウンが図れ
る。Low-temperature sintering makes it possible to use inexpensive base metals and dielectric oxides as materials for the internal electrodes, thereby reducing costs.
更に、具体的に説明する。 This will be described more specifically.
コンデンサにおける層構成は、第１図に示す層構成と
同じである。The layer configuration of the capacitor is the same as the layer configuration shown in FIG.
まず、セラミック誘電体原料であるBaTiO3粉末に、金
属銅粉末を添加し、エタノール中で12時間混合し、乾燥
させ、金属銅粉末が均一に混ざった原料粉末を得た。First, metallic copper powder was added to BaTiO 3 powder as a ceramic dielectric raw material, mixed in ethanol for 12 hours, and dried to obtain a raw material powder in which metallic copper powder was uniformly mixed.
そして、これら原料粉末と内部電極用材料を用い、セ
ラミック誘電体原料層と内部電極用材料層が交互に積層
された積層体を、従来と同様の方法で作った。この後、
1100℃で焼成させてコンデンサを得た。Using these raw material powders and the internal electrode material, a laminate in which ceramic dielectric raw material layers and internal electrode material layers were alternately laminated was produced in the same manner as the conventional method. After this,
The capacitor was obtained by firing at 1100 ° C.
なお、セラミック誘電体層が1100℃の低い温度で十分
に焼結されていることを、以下のようにして確認した。It was confirmed as follows that the ceramic dielectric layer was sufficiently sintered at a low temperature of 1100 ° C.
金属銅粉末を添加した原料粉末で直径13mmのペレット
を作った。金属銅粉末の添加量は、0.5wt％、1.0wt％、
5.0wt％の３通りである。各ペレットを、様々な温度で
２時間焼成し収縮率を調べた。収縮率と焼結進度は略比
例関係にある。比較のために金属銅粉末を添加しないペ
レットも作り同様に焼成し収縮率を調べた。結果を第２
図に示す。Pellets having a diameter of 13 mm were made from the raw material powder to which the metallic copper powder was added. The addition amount of metallic copper powder is 0.5wt%, 1.0wt%,
There are three types of 5.0 wt%. Each pellet was fired at various temperatures for 2 hours and the shrinkage was examined. The shrinkage ratio and the sintering progress are in a substantially proportional relationship. For comparison, a pellet without the addition of metallic copper powder was also prepared and fired in the same manner, and the shrinkage was examined. Second result
Shown in the figure.
第２図にみるように、金属銅粉末を添加したペレット
は、1100℃の温度で、金属銅粉末未添加のペレットの13
50℃の焼結温度のものと同じ収縮率、すなわち十分な焼
結状態になっていることが分かる。As shown in FIG. 2, the pellets to which the metallic copper powder had been added were at a temperature of 1100 ° C.
It can be seen that the shrinkage rate is the same as that at the sintering temperature of 50 ° C., that is, a sufficiently sintered state.
また、比較のために、金属銅粉末を添加せず、1300℃
で焼結させるようにした他は、全く同様にしてコンデン
サを得た。For comparison, 1300 ° C without adding metallic copper powder
A capacitor was obtained in exactly the same manner as above except for sintering.
実施列と比較例のコンデンサの特性を比べてみたとこ
ろ殆ど差がなく、特性劣化を伴うことなく、金属銅粉末
の添加により焼結温度を200℃程度低くすることができ
ることが確認できた。When the characteristics of the capacitors of the working example and the comparative example were compared, there was almost no difference, and it was confirmed that the sintering temperature could be lowered by about 200 ° C. by adding the metal copper powder without deterioration of the characteristics.
発明の効果 以上に述べたように、この発明のコンデンサは、セラ
ミック誘電体層に焼結助剤として金属銅粉末を含んでい
るため、十分な特性を保ちつつ低温焼成が可能となり、
これに従って、内部電極用材料として卑金属や誘電性酸
化物が使え大幅なコストダウンが可能となる。Effect of the Invention As described above, since the capacitor of the present invention contains metallic copper powder as a sintering aid in the ceramic dielectric layer, low-temperature firing is possible while maintaining sufficient characteristics,
Accordingly, a base metal or a dielectric oxide can be used as a material for the internal electrode, thereby enabling a significant cost reduction.
第１図は、この発明のかかるコンデンサの層構成をあら
わす模式的断面図、第２図は、焼結進度確認用ペレット
の焼成温度と収縮率の関係をあらわすグラフである。 １……セラミック誘電体層、２……内部電極層、３……
接続電極。FIG. 1 is a schematic cross-sectional view showing the layer structure of such a capacitor according to the present invention, and FIG. 2 is a graph showing the relationship between the firing temperature and the shrinkage rate of the sintering progress confirmation pellet. 1 ... ceramic dielectric layer, 2 ... internal electrode layer, 3 ...
Connection electrode.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 吉村 進 神奈川県川崎市多摩区東三田３丁目10番 １号 松下技研株式会社内 (58)調査した分野(Int.Cl.6，ＤＢ名) H01G 4/12 H01G 4/30──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Susumu Yoshimura 3-1-1, Higashi-Mita, Tama-ku, Kawasaki-shi, Kanagawa Matsushita Giken Co., Ltd. (58) Field surveyed (Int.Cl. 6 , DB name) H01G 4/12 H01G 4/30
Claims (1)
結されてなり、前記セラミック誘電体層が焼結助剤とし
て金属銅粉末を0.1〜5.0wt％含んで焼結されてなる積層
セラミックコンデンサ。1. A laminated ceramic comprising a ceramic dielectric layer and an internal electrode layer laminated and sintered, and said ceramic dielectric layer sintered with 0.1 to 5.0 wt% of metallic copper powder as a sintering aid. Capacitors.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29020289A JP2775916B2 (en) | 1989-11-08 | 1989-11-08 | Multilayer ceramic capacitors |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29020289A JP2775916B2 (en) | 1989-11-08 | 1989-11-08 | Multilayer ceramic capacitors |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH03151613A JPH03151613A (en) | 1991-06-27 |
| JP2775916B2 true JP2775916B2 (en) | 1998-07-16 |
Family
ID=17753076
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP29020289A Expired - Fee Related JP2775916B2 (en) | 1989-11-08 | 1989-11-08 | Multilayer ceramic capacitors |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2775916B2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5718167B2 (en) * | 2011-06-13 | 2015-05-13 | 日本特殊陶業株式会社 | Electronic components |
-
1989
- 1989-11-08 JP JP29020289A patent/JP2775916B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH03151613A (en) | 1991-06-27 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |