JPH04352407A - Laminated ceramic capacitor - Google Patents
Laminated ceramic capacitorInfo
- Publication number
- JPH04352407A JPH04352407A JP12712291A JP12712291A JPH04352407A JP H04352407 A JPH04352407 A JP H04352407A JP 12712291 A JP12712291 A JP 12712291A JP 12712291 A JP12712291 A JP 12712291A JP H04352407 A JPH04352407 A JP H04352407A
- Authority
- JP
- Japan
- Prior art keywords
- electrode
- ceramic capacitor
- multilayer ceramic
- solder layer
- external
- 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.)
- Pending
Links
Landscapes
- Ceramic Capacitors (AREA)
- Fixed Capacitors And Capacitor Manufacturing Machines (AREA)
Abstract
(57)【要約】本公報は電子出願前の出願データであるた
め要約のデータは記録されません。(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.
Description
［発明の目的］ [Purpose of the invention]
【０００１】0001
【産業上の利用分野】本発明は積層セラミックコンデン
サに係り、特に、その外部電極の構造に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer ceramic capacitor, and more particularly to the structure of its external electrode.
【０００２】0002
【従来の技術】積層セラミックコンデンサは、一般に平
滑な誘電体層と内部電極とを交互に積層し、この内部電
極露出側面に接合する様に外部電極が構成されてなる。
この外部電極の構造は、銀、パラジウム及び樹脂を中心
とした下層電極と、この下層電極上に導電性接着剤を介
して取付けた上部電極としての金属キャップ状ターミナ
ルとから構成されている。2. Description of the Related Art Multilayer ceramic capacitors generally consist of alternately laminated smooth dielectric layers and internal electrodes, with external electrodes connected to exposed side surfaces of the internal electrodes. The structure of this external electrode consists of a lower layer electrode mainly made of silver, palladium, and resin, and a metal cap-shaped terminal as an upper electrode attached to the lower layer electrode via a conductive adhesive.
【０００３】この外部電極には、積層セラミックコンデ
ンサを基板に実装した際、コンデンサの電気的特性を基
板側へ伝える役割と、コンデンサの寿命性及び信頼性を
向上させる役割とがある。信頼性試験の１つである熱衝
撃試験では、金属キャップ状ターミナルを固着している
導電性接着剤によって、熱衝撃の応力を吸収するため、
良好な特性を得ている。しかしながら、耐湿試験におい
ては、不充分であり良好な特性を得ていない。これは、
外部電極の構造が耐湿性に適さないポーラス形態である
ためである。したがって、下層の電極部分より水分が浸
み込んでしまいさらにセラミック焼結体内にマイクロス
クラッチ等が存在すると、ショート不良が発生する問題
がある。[0003] When a multilayer ceramic capacitor is mounted on a substrate, this external electrode has the role of transmitting the electrical characteristics of the capacitor to the substrate side and the role of improving the life span and reliability of the capacitor. In the thermal shock test, which is one of the reliability tests, the stress of thermal shock is absorbed by the conductive adhesive that fixes the metal cap-shaped terminal.
Good characteristics have been obtained. However, the moisture resistance test was insufficient and good characteristics were not obtained. this is,
This is because the structure of the external electrode is porous, which is not suitable for moisture resistance. Therefore, if moisture seeps in from the lower electrode portion and microscratches or the like are present in the ceramic sintered body, there is a problem that short-circuit failure may occur.
【０００４】0004
【発明が解決しようとする課題】上述の課題を解決する
ため、本発明は外部電極から吸水させない構造とした積
層セラミックコンデンサを提供することを課題とする。
［発明の構成］SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, it is an object of the present invention to provide a multilayer ceramic capacitor having a structure that prevents water from being absorbed from the external electrodes. [Structure of the invention]
【０００５】[0005]
【課題を解決するための手段】上述の課題を達成するた
め、本発明の積層セラミックコンデンサでは、外部電極
が半田融着されやすい組成からなる下層電極と、この下
層電極表面上に形成された半田層と、この半田層上に配
置された上部電極とからなることを特徴とするものであ
る。[Means for Solving the Problems] In order to achieve the above-mentioned problems, in the multilayer ceramic capacitor of the present invention, the outer electrode has a lower layer electrode having a composition that is easily solder fused, and a solder layer formed on the surface of the lower layer electrode. The solder layer is characterized by comprising a solder layer and an upper electrode disposed on the solder layer.
【０００６】[0006]
【作用】従来の積層セラミックコンデンサでは、耐湿負
荷試験（温度８５℃、温度９５％、定格負荷）を実施し
たところ、５００時間にて電気的特性の不良率が約３０
％に達してしまう。この原因は、外部電極の下層電極の
吸水作用にある。すなわち、下層電極は、銀、パラジウ
ム及び樹脂成分にて形成されているため、ポーラス形態
であり吸水性が高くなる。この結果、下層電極に水分が
しみこんで外部電極と内部電極との間のショート不良が
発生してしまい、絶線抵抗の低下をまねくことになる。[Function] When a humidity load test (temperature 85°C, temperature 95%, rated load) was carried out on conventional multilayer ceramic capacitors, the failure rate of electrical characteristics was approximately 30 after 500 hours.
%. The cause of this is the water absorption effect of the lower layer electrode of the external electrode. That is, since the lower layer electrode is formed of silver, palladium, and a resin component, it has a porous form and has high water absorption. As a result, moisture seeps into the lower electrode, causing a short circuit between the external electrode and the internal electrode, resulting in a decrease in wire resistance.
【０００７】これに対し、本発明の積層セラミックコン
デンサの外部電極では、下層電極の表面上に耐湿性を有
している半田層を形成している。このため、水分がセラ
ミック焼結体内部に浸み込まなくなり、絶縁抵抗の低下
は発生することがなくなり、耐湿特性に強くなる。In contrast, in the external electrode of the multilayer ceramic capacitor of the present invention, a moisture-resistant solder layer is formed on the surface of the lower electrode. Therefore, moisture does not penetrate into the ceramic sintered body, and the insulation resistance does not decrease, resulting in strong moisture resistance.
【０００８】[0008]
【実施例】以下本発明の実施例を図面に基づいて説明す
る。DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the drawings.
【０００９】第１図において、積層セラミックコンデン
サは、セラミック誘電体層（１）と、内部電極（２）と
を交互に積層し、この個々の内部電極（２）と電気的に
接続する様にセラミック誘電体層（１）と内部電極（２
）との端部に外部電極の下層電極（３）を形成し、この
下層電極（３）の表面上に半田層（４）を形成し、この
半田層（４）上に導電性接着剤（５）を介して外部電極
の上部電極として金属キャップ状ターミナル（６）を被
着形成して構成されている。したがって、外部電極は、
下層電極（３）と半田層（４）と導電性接着剤（５）と
金属キャップ状ターミナル（６）とから構成されている
。次に外部電極の形成方法を述べる。なお、内部電極（
２）等の形成方法は従来技術と同じであるため、説明を
省略する。In FIG. 1, the multilayer ceramic capacitor has ceramic dielectric layers (1) and internal electrodes (2) alternately laminated and electrically connected to each internal electrode (2). Ceramic dielectric layer (1) and internal electrode (2)
A lower electrode (3) of the external electrode is formed at the end of the outer electrode (3), a solder layer (4) is formed on the surface of this lower electrode (3), and a conductive adhesive ( A metal cap-shaped terminal (6) is attached and formed as the upper electrode of the external electrode via the outer electrode (5). Therefore, the external electrode is
It is composed of a lower electrode (3), a solder layer (4), a conductive adhesive (5), and a metal cap-shaped terminal (6). Next, a method for forming the external electrodes will be described. Note that the internal electrode (
Since the forming method of 2) etc. is the same as the conventional technique, the explanation will be omitted.
【００１０】この下層電極（３）は銀及びパラジウムを
中心とした半田の融着しやすい組成からなり、この下層
電極（３）ペーストをセラミック誘電層（１）の内部電
極（２）の露出部に塗布し、焼付けて形成する。次に下
層電極（３）の表面上に融点の高い（３００℃以上）半
田を溶融した状態にて、半田ディップして半田層（４）
を形成する。次いで金属キャップ状ターミナル（６）を
熱硬化型導電性接着剤（５）を介して嵌合して取り付け
る。This lower electrode (3) is made of a composition that is easy to fuse with solder, mainly silver and palladium, and this lower electrode (3) paste is applied to the exposed portion of the internal electrode (2) of the ceramic dielectric layer (1). It is formed by coating and baking. Next, melted solder with a high melting point (300°C or higher) is dipped onto the surface of the lower electrode (3) to form a solder layer (4).
form. Next, a metal cap-shaped terminal (6) is fitted and attached via a thermosetting conductive adhesive (5).
【００１１】第１図に示す積層セラミックコンデンサに
おいて、信頼性試験の１つである耐湿負荷試験（温度８
５℃、湿度９５％、定格負荷）を実施したところ、５０
０時間経過した時点において、積層セラミックコンデン
サの電気的特性の不良率は０％と良好な結果を得られた
。また、熱衝撃試験においても同じく良好であった。In the multilayer ceramic capacitor shown in FIG. 1, a humidity load test (temperature 8
5℃, humidity 95%, rated load), 50
After 0 hours had elapsed, the failure rate of the electrical characteristics of the multilayer ceramic capacitor was 0%, which was a good result. In addition, it also performed well in a thermal shock test.
【００１２】0012
【発明の効果】上述の構成をとることにより、本発明の
積層セラミックコンデンサは、外部電極の下層電極の表
面上に耐湿性及び導電性を有している半田層を形成して
いるため、積層セラミックコンデンサとしての電気的特
性を劣化させることなく、多湿環境状態における信頼性
を大幅に向上させることが出来る。[Effects of the Invention] By adopting the above-described structure, the multilayer ceramic capacitor of the present invention has a moisture-resistant and conductive solder layer formed on the surface of the lower electrode of the external electrode. Reliability in a humid environment can be significantly improved without deteriorating the electrical characteristics of a ceramic capacitor.
【図１】本発明の積層セラミックコンデンサの実施例を
示す正面断面図である。FIG. 1 is a front sectional view showing an embodiment of a multilayer ceramic capacitor of the present invention.
（１）…セラミックス誘電体層 （２）
…内部電極
（３）…外部電極の下層電極 （４
）…半田層（５）…導電性接着剤
（６）…外部電極の上層電極としての金属キャップ状タ
ーミナル(1)...Ceramic dielectric layer (2)
...Internal electrode (3) ...Lower electrode of external electrode (4
)...Solder layer (5)...Conductive adhesive (6)...Metal cap-shaped terminal as upper layer electrode of external electrode
Claims (1)
た積層体と、この積層体を構成するこの内部電極に電気
的に接続する外部電極とを備えた積層セラミックコンデ
ンサにおいて、前記外部電極は、半田融着されやすい組
成からなる下層電極と、この下層電極表面上に形成され
た半田層と、この半田層上に配置された上部電極とから
なることを特徴とする積層セラミックコンデンサ。1. A multilayer ceramic capacitor comprising a laminate in which dielectric layers and internal electrodes are alternately laminated, and an external electrode electrically connected to the internal electrode constituting the laminate, wherein the external electrode A multilayer ceramic capacitor comprising a lower electrode having a composition that is easily soldered, a solder layer formed on the surface of the lower electrode, and an upper electrode disposed on the solder layer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12712291A JPH04352407A (en) | 1991-05-30 | 1991-05-30 | Laminated ceramic capacitor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP12712291A JPH04352407A (en) | 1991-05-30 | 1991-05-30 | Laminated ceramic capacitor |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH04352407A true JPH04352407A (en) | 1992-12-07 |
Family
ID=14952154
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP12712291A Pending JPH04352407A (en) | 1991-05-30 | 1991-05-30 | Laminated ceramic capacitor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH04352407A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008166301A (en) * | 2006-12-26 | 2008-07-17 | Tdk Corp | Electronic component and its mounting structure |
-
1991
- 1991-05-30 JP JP12712291A patent/JPH04352407A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008166301A (en) * | 2006-12-26 | 2008-07-17 | Tdk Corp | Electronic component and its mounting structure |
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