JP3524298B2 - Method of forming external electrodes of multilayer ceramic capacitor - Google Patents
Method of forming external electrodes of multilayer ceramic capacitorInfo
- Publication number
- JP3524298B2 JP3524298B2 JP28706096A JP28706096A JP3524298B2 JP 3524298 B2 JP3524298 B2 JP 3524298B2 JP 28706096 A JP28706096 A JP 28706096A JP 28706096 A JP28706096 A JP 28706096A JP 3524298 B2 JP3524298 B2 JP 3524298B2
- Authority
- JP
- Japan
- Prior art keywords
- internal electrode
- electrode
- metal film
- body piece
- ceramic capacitor
- 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
【０００１】[0001]
【発明の属する技術分野】本発明は積層セラミックコン
デンサの外部電極の形成方法に関し、特に内部電極と外
部電極の接続性を良好にでき、かつセラミックの本体片
と密着強度の高い薄膜の外部電極の形成方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming an external electrode of a monolithic ceramic capacitor, and more particularly to a thin film external electrode which has good adhesion between an internal electrode and an external electrode and has a high adhesion strength with a ceramic body piece. It relates to a forming method.
【０００２】[0002]
【従来の技術】一般に薄膜の外部電極を有する積層セラ
ミックコンデンサは、図４の断面図に示すように、セラ
ミックからなる六面体に形成された本体片１の内部に、
複数枚のＰｄ又はＰｄ−Ａｇ合金からなる内部電極２が
交互に積層状に配設され、この本体片１における六つの
側面のうち内部電極２が露出する一対の側端面に、内部
電極２と導通する薄膜による外部電極３が形成されてい
る。2. Description of the Related Art Generally, a monolithic ceramic capacitor having a thin film external electrode is, as shown in the cross-sectional view of FIG. 4, inside a body piece 1 formed into a hexahedron made of ceramic,
The internal electrodes 2 made of a plurality of Pd or Pd-Ag alloys are alternately arranged in a laminated form, and the internal electrodes 2 are provided on a pair of side end faces of the body piece 1 where the internal electrodes 2 are exposed. The external electrode 3 is formed of a conductive thin film.
【０００３】この外部電極３は、セラミックとの密着強
度の高いＣｒからなる第一電極層３ａと、ハンダ食われ
防止用のバリア金属となるＮｉからなる第二電極層３ｂ
と、ハンダ付け性の良いＡｇからなる第三電極層３ｃと
から構成され、スパッタリング法，真空蒸着法又はプラ
ズマ溶射法により形成される。ところで、上述の積層セ
ラミックコンデンサでは、内部電極２と外部電極３との
接続を確実に行うことが重要であるため、内部電極２を
設けた本体片１を焼成した後、内部電極２を本体片１の
側端面から十分露出させるためにバレル研磨を施した
後、本体片１の側端面に薄膜の外部電極３を形成してい
る。The external electrode 3 comprises a first electrode layer 3a made of Cr, which has a high adhesion strength with ceramics, and a second electrode layer 3b made of Ni, which is a barrier metal for preventing solder erosion.
And a third electrode layer 3c made of Ag having good solderability and formed by a sputtering method, a vacuum deposition method or a plasma spraying method. By the way, in the above-mentioned monolithic ceramic capacitor, it is important to securely connect the internal electrode 2 and the external electrode 3. Therefore, after firing the main body piece 1 provided with the internal electrode 2, the internal electrode 2 is attached to the main body piece. After performing barrel polishing so as to be sufficiently exposed from the side end surface of 1, the thin film external electrode 3 is formed on the side end surface of the main body piece 1.
【０００４】しかしながら、バレル研磨の不十分、内部
電極２の過薄、内部電極２の露出部分での欠落、内部電
極２へのセラミック被覆等に起因し、内部電極２と外部
電極３との接続が不十分となる場合があり、静電容量の
損失、誘電正接（ｔａｎδ）の増大等の不具合を発生さ
せる原因となっていた。この問題を解決するために、例
えば、図５に示すような特開平６−５４６１に示す方法
では、本体片１をバレル研磨した後、耐熱容器１０内に
Ａｇ粉末（金属粉末）１１とＺｒＯ2粉末（セラミック
粉末）とを入れて混合し、この混合中にＰｄ又はＰｄ−
Ａｇ合金からなる内部電極２を有する本体片１を混在さ
せて、５００〜９００℃で熱処理することでＡｇ粉末１
１を内部電極２側に拡散させて合金を形成し、実質的に
内部電極２を長くして本体片１の側端面から十分露出さ
せることができる。その結果、内部電極２と薄膜の外部
電極３との接触が確実になる。However, the internal electrode 2 and the external electrode 3 are connected to each other due to insufficient barrel polishing, thinning of the internal electrode 2, loss of the exposed portion of the internal electrode 2, ceramic coating on the internal electrode 2, and the like. May be insufficient, causing problems such as loss of capacitance and increase of dielectric loss tangent (tan δ). In order to solve this problem, for example, in the method disclosed in JP-A-6-5461 as shown in FIG. 5, after the body piece 1 is barrel-polished, Ag powder (metal powder) 11 and ZrO 2 are placed in the heat-resistant container 10. Powder (ceramic powder) is added and mixed, and during this mixing, Pd or Pd-
Ag powder 1 is obtained by mixing body piece 1 having internal electrode 2 made of an Ag alloy and heat-treating at 500 to 900 ° C.
1 can be diffused to the internal electrode 2 side to form an alloy, and the internal electrode 2 can be substantially lengthened to be sufficiently exposed from the side end surface of the main body piece 1. As a result, the contact between the internal electrode 2 and the thin film external electrode 3 is ensured.
【０００５】[0005]
【発明が解決しようとする課題】しかしながら、上述の
方法では耐熱容器１０内のＡｇ粉末１１が焼結してしま
い、再利用が困難というコスト的な問題が生じていた。
また、を内部電極２側に十分拡散させようとすると粉末
自体が固まってしまい本体片１が取り出せなくなる場合
があった。また、本体片１の表面全体にＡｇ粉末１１が
付着してしまい絶縁性が劣化するおそれがあった。However, in the above-mentioned method, the Ag powder 11 in the heat-resistant container 10 is sintered, which causes a cost problem that it is difficult to reuse.
Further, if the powder is hardened to be sufficiently diffused to the internal electrode 2 side, the powder itself may be hardened and the main body piece 1 may not be taken out. In addition, the Ag powder 11 may adhere to the entire surface of the main body piece 1 to deteriorate the insulating property.
【０００６】さらに、内部電極２を実質的に長くするた
めにＡｇ粉末１１を拡散させているが、内部電極２との
合金形成に利用されなかったＡｇ粉末１１は本体片１の
側端面に付着したままとなる。この状態で３層かならる
外部電極３を形成すると、第一電極層３ａとしてセラミ
ックとの密着強度の高いＣｒを使用しているにも拘わら
ず、本体片１と第一電極層３ａとの間にセラミックとの
密着強度が低いＡｇ粉末１１が存在するために、外部電
極３の密着強度が低くなるという問題も生じていた。Further, the Ag powder 11 is diffused in order to substantially lengthen the internal electrode 2, but the Ag powder 11 not used for alloying with the internal electrode 2 adheres to the side end surface of the body piece 1. It will remain. When the external electrode 3 having three layers is formed in this state, the main electrode piece 1 and the first electrode layer 3a are not separated from each other despite the use of Cr having high adhesion strength with the ceramic as the first electrode layer 3a. Since the Ag powder 11 having a low adhesion strength with the ceramic is present between them, there is a problem that the adhesion strength of the external electrode 3 becomes low.
【０００７】本発明の目的は、上述した問題点に鑑み、
内部電極と外部電極との接続を確実にし、絶縁性，作業
性，コスト及び外部電極と本体片の密着性を改善できる
薄膜による積層セラミックコンデンサの外部電極の形成
方法を提供することにある。The object of the present invention is to solve the above-mentioned problems.
It is an object of the present invention to provide a method of forming an external electrode of a multilayer ceramic capacitor by a thin film, which can ensure the connection between the internal electrode and the external electrode, and can improve the insulating property, workability, cost and adhesion between the external electrode and the body piece.
【０００８】[0008]
【課題を解決するための手段】本発明は、上記目的を達
成するために次のような構成をとる。すなわち、本発明
の積層セラミックコンデンサの外部電極の形成方法は、
セラミックよりなる本体片の内部に複数枚の内部電極を
配設し前記本体片から内部電極を露出させた後、前記本
体片の側端面にセラミックに対し密着強度の高い第一金
属膜と内部電極材料と異なる拡散係数を持つ第二金属膜
をこの順で形成し熱処理を施した後、前記内部電極と導
通する外部電極を設けることを特徴とするものである。The present invention has the following constitution in order to achieve the above object. That is, the method for forming the external electrodes of the multilayer ceramic capacitor of the present invention is
After disposing a plurality of internal electrodes inside the body piece made of ceramic and exposing the inner electrode from the body piece, the first metal film and the inner electrode having high adhesion strength to the ceramic on the side end surface of the body piece. A second metal film having a diffusion coefficient different from that of the material is formed in this order, heat treatment is performed, and then an external electrode that is electrically connected to the internal electrode is provided.
【０００９】また、本発明の積層セラミックコンデンサ
の外部電極の形成方法は、前記金属膜の拡散係数が前記
内部電極材料より大きいことを特徴とするものである。
本発明よれば、セラミックに対して密着強度の高い第一
金属膜を形成した後、内部電極の材料と異なる拡散係数
を持つ第二金属膜を形成して熱処理を施すと、この第二
金属膜が第一金属膜を通過して内部電極側に拡散が起こ
り、内部電極と第二金属膜との間に合金が形成される。
その結果、内部電極が実質的に長くなり、本体片の側端
面から十分露出されて内部電極と外部電極との接続がよ
り確実になるとともに、密着強度の高い外部電極を形成
することができる。The method of forming the external electrodes of the monolithic ceramic capacitor of the present invention is characterized in that the diffusion coefficient of the metal film is larger than that of the internal electrode material.
According to the present invention, after the first metal film having high adhesion strength to the ceramic is formed, the second metal film having a diffusion coefficient different from that of the material of the internal electrode is formed and the heat treatment is performed. Passes through the first metal film and diffuses toward the internal electrode, forming an alloy between the internal electrode and the second metal film.
As a result, the internal electrode becomes substantially long, is sufficiently exposed from the side end surface of the main body piece, and the connection between the internal electrode and the external electrode is more reliable, and the external electrode having high adhesion strength can be formed.
【００１０】特に、金属膜の拡散係数が内部電極材料よ
り大きいので、内部電極に金属膜が第一電極層を通過し
て入り込み、内部電極材料と金属膜との間に合金が形成
されて内部電極の実質的に長くなり本体片の側端面から
確実に露出するようになる。In particular, since the diffusion coefficient of the metal film is larger than that of the internal electrode material, the metal film enters the internal electrode through the first electrode layer , and an alloy is formed between the internal electrode material and the metal film to form an internal electrode. The electrode is substantially lengthened and it is surely exposed from the side end surface of the main body piece.
【００１１】[0011]
【発明の実施の形態】以下、本発明の実施例を、図面を
参照しつつ具体的に説明する。まず、図１（ａ）に示す
ように、酸化チタンやチタン酸バリウム及びＰｂ系の複
合ペロブスカイト型化合物の誘電体材料を有機バインダ
ーに分散させたグリーンシート１３上に、完成時には内
部電極となるＡｇ−Ｐｄ系，Ｐｄ等の金属を含む導電ペ
ースト１４をスクリーン印刷し、このグリーンシート１
３を所定枚数（２０〜１００枚程度）積み重ねて熱圧着
する。その後、熱圧着したグリーンシート１３を切断線
１５に沿って切断し、所定寸法の積層セラミックコンデ
ンサの本体片１を得る。BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be specifically described below with reference to the drawings. First, as shown in FIG. 1A, on a green sheet 13 in which a dielectric material such as titanium oxide, barium titanate, and a Pb-based complex perovskite compound is dispersed in an organic binder, Ag that will become an internal electrode when completed is formed. This green sheet 1 is obtained by screen-printing a conductive paste 14 containing a metal such as -Pd or Pd.
A predetermined number (about 20 to 100) of 3 are stacked and thermocompression bonded. Then, the thermocompression-bonded green sheet 13 is cut along the cutting line 15 to obtain the body piece 1 of the multilayer ceramic capacitor having a predetermined size.
【００１２】そして、同図（ｂ）に示すように、本体片
１を仮焼成して脱バインダーした後焼成し、本体片１の
一対の側端面から内部電極２が露出するようにバレル研
磨を施す。しかし、本体片１内においては丸印で囲んだ
ように複数枚（ここでは２枚）の内部電極２が側端面か
ら十分に露出していないことがあり、この状態で従来の
方法で薄膜の外部電極を本体片１の側端面に形成する
と、内部電極２と外部電極との接続が不十分となり、静
電容量の損失、誘電正接（ｔａｎδ）の増大等の不具合
を発生するおそれがある。Then, as shown in FIG. 1B, the main body piece 1 is pre-baked to remove the binder and then fired, and barrel polishing is performed so that the internal electrodes 2 are exposed from a pair of side end surfaces of the main body piece 1. Give. However, in the body piece 1, a plurality of (in this case, two) internal electrodes 2 may not be sufficiently exposed from the side end faces as surrounded by circles. When the external electrode is formed on the side end surface of the main body piece 1, the connection between the internal electrode 2 and the external electrode becomes insufficient, which may cause problems such as loss of capacitance and increase of dielectric loss tangent (tan δ).
【００１３】そこで、同図（ｃ）に示すように、本体片
１を収納するための多数の貫通孔１６を有する枠部１７
を底板１８の上に固定した治具を準備し、貫通孔１６内
に側端面が上を向くように本体片１を挿入する。そし
て、この治具を側端面に金属膜を形成できる装置、例え
ばスパッタリング装置、にセットする。そして、本発明
では内部電極２との間で拡散を生じる金属膜を形成する
前に、図２（ｄ）に示すように、スパッタリングにより
体片１の両側端面に、セラミックに対して密着性の高い
Ｃｒ，Ｍｎ又はＡｌからなる第一金属膜４ａを膜厚０．
１〜１μｍ程度となるように形成した後、Ａｇ−Ｐｄ系
又はＰｄ等の金属からなる内部電極２より拡散係数の大
きい金属、例えばＡｇを膜厚０．５〜２μｍ程度となる
第二金属膜４ｂを形成する。Therefore, as shown in FIG. 1C, a frame portion 17 having a large number of through holes 16 for accommodating the body piece 1.
A jig in which is fixed on the bottom plate 18 is prepared, and the main body piece 1 is inserted into the through hole 16 so that the side end surface faces upward. Then, this jig is set in an apparatus capable of forming a metal film on the side end surface, for example, a sputtering apparatus. Then, according to the present invention, before forming a metal film that causes diffusion with the internal electrode 2, as shown in FIG. The first metal film 4a made of high Cr, Mn or Al has a film thickness of 0.
After being formed to have a thickness of about 1 to 1 μm, a metal having a diffusion coefficient larger than that of the internal electrode 2 made of a metal such as Ag-Pd or Pd, for example, Ag, a second metal film having a thickness of about 0.5 to 2 μm. 4b is formed.
【００１４】次に、第一金属膜４ａ及び第二金属膜４ｂ
が形成された本体片１を治具を取り出して、トンネル炉
内にセットし、昇温温度３０℃／分で，最高温度８５０
℃を１０分保持し、側端面に金属膜４が形成された本体
片１に熱処理を施す。熱処理を施すと、図２（ｅ）に示
すように、拡散係数の違いにより第二金属膜４ｂが第一
金属膜４ａを通過して本来露出されるべき内部電極２と
の間で拡散が起こり、本体片１の側端面付近で第二金属
膜４ｂと内部電極２の合金５が形成され、内部電極２が
実質的に延長され、本体片１の側端面から十分露出する
ようになる。Next, the first metal film 4a and the second metal film 4b
The main body piece 1 on which is formed is taken out of the jig, set in a tunnel furnace, and the maximum temperature is 850 at a temperature rise temperature of 30 ° C./min.
The temperature is kept at 10 ° C. for 10 minutes, and the main body piece 1 having the metal film 4 formed on the side end surface is heat-treated. When heat treatment is applied, as shown in FIG. 2E, due to the difference in diffusion coefficient, the second metal film 4b passes through the first metal film 4a and is diffused with the internal electrode 2 that should be originally exposed. The alloy 5 of the second metal film 4b and the internal electrode 2 is formed in the vicinity of the side end surface of the main body piece 1, the internal electrode 2 is substantially extended, and is sufficiently exposed from the side end surface of the main body piece 1.
【００１５】特に、本発明では、Ａｇからなる第二金属
膜４ｂの拡散係数がＡｇ−Ｐｄ系又はＰｄ系の内部電極
２より大きいので、第二金属膜４ｂが第一電極膜４ａを
通過して内部電極２側に入り込み、本体片１の側端面付
近に合金５が形成されることになる。他方内部電極２の
非接続端側では内部電極２と金属膜４との間には一定の
間隔で離間されているので、上述の拡散作用による合金
形成がほとんど生じない。In particular, in the present invention, since the diffusion coefficient of the second metal film 4b made of Ag is larger than that of the Ag-Pd-based or Pd-based internal electrode 2, the second metal film 4b passes through the first electrode film 4a. And enters the internal electrode 2 side, and the alloy 5 is formed near the side end surface of the main body piece 1. On the other hand, on the non-connection end side of the internal electrode 2, since the internal electrode 2 and the metal film 4 are separated by a constant distance, the alloy formation due to the above-mentioned diffusion action hardly occurs.
【００１６】かかる場合、内部電極２の拡散係数が第二
金属膜４ｂより大きいとすれば、内部電極２が近接する
側端面側に拡散して合金５が形成されるが、内部電極２
が拡散された分膜厚が薄くり、内部電極２の一部が断線
するおそれが生じる。しかしながら、本願では第二金属
膜４ａの拡散係数が大きいのでこのような問題は生じな
い。In such a case, if the diffusion coefficient of the internal electrode 2 is larger than that of the second metal film 4b, the alloy 5 is formed by diffusing to the side surface of the side where the internal electrode 2 approaches, but the internal electrode 2
The thickness of the diffused film becomes small, and there is a possibility that a part of the internal electrode 2 will be disconnected. However, in the present application, since the diffusion coefficient of the second metal film 4a is large, such a problem does not occur.
【００１７】なお、本実施例では、熱処理を８５０℃の
温度で行ったが、第二金属膜４ｂと内部電極２との間で
拡散が生じればよく、５００℃〜９００℃の間で適宜選
択することができる。次いで、側端面付近に合金５が形
成された本体片１を、図１（ｃ）と同様の治具に側端面
が上を向くように本体片１を挿入し、外部電極を形成す
るための装置、例えばスパッタリング装置、に治具ごと
セットする。In the present embodiment, the heat treatment was performed at a temperature of 850 ° C., but it is sufficient that diffusion occurs between the second metal film 4b and the internal electrode 2, and it is appropriately between 500 ° C. and 900 ° C. You can choose. Next, the body piece 1 on which the alloy 5 is formed near the side end surface is inserted into a jig similar to that shown in FIG. 1C so that the side end surface faces upward, so as to form an external electrode. The jig is set in an apparatus, for example, a sputtering apparatus.
【００１８】そして、この本体片１にスパッタリングを
施して、図２（ｆ）に示すように外部電極３を形成す
る。外部電極３の形成方法は、第一金属膜４ａ及び第二
金属膜４ｂが両側端面に形成された本体片１の一方の側
端面に第ハンダ食われ防止用のバリア金属となるＮｉか
らなる第一電極層３ａを形成し、次にハンダ付け性の良
いＡｇ等の金属材料からなる第二電極層３ｂを形成す
る。さらに、一方の外部電極３を形成した後、治具を裏
返して本体片１の他方の側端面が上を向くようにし、上
述と同様に２種類の電極材料をスパッタリングし、第一
電極層３ａ，第二電極層３ｂからなる外部電極３を形成
する。Then, the main body piece 1 is subjected to sputtering to form an external electrode 3 as shown in FIG. 2 (f). The method for forming the external electrode 3 is as follows. One electrode layer 3a is formed, and then a second electrode layer 3b made of a metal material such as Ag having good solderability is formed. Further, after forming the one external electrode 3, the jig is turned over so that the other side end surface of the main body piece 1 faces upward, and two kinds of electrode materials are sputtered in the same manner as described above to form the first electrode layer 3a. , The external electrode 3 including the second electrode layer 3b is formed.
【００１９】この図からも明らかなように、内部電極２
は金属膜４ｂとの合金５の形成により側端面から十分露
出しており、内部電極２と外部電極３とは確実に電気的
に接続することになる。本発明の実施例では、内部電極
２としてＡｇ−Ｐｄ系，Ｐｄを、第二金属膜４ｂとして
Ａｇを使用したが、拡散係数が内部電極より金属膜が大
きければどのような金属材料を使用しも良い。ここで拡
散係数について説明すると、金属の拡散係数は一般に次
の式で与えられる。
Ｄ＝Ｄ0ｅｘｐ（−Ｑ／ＲＴ）
Ｄ：拡散係数(cm2/sec)
Ｄ0：拡散の振動数項(cm2/sec)
Ｑ：活性化エネルギー(kcal/mol)
Ｒ：気体定数(1.986cal/K・mol)
Ｔ：絶対温度(K)
ただし、拡散の振動数項Ｄ0，活性化エネルギーＱは自
己拡散の実験によって決定された金属材料固有の数値で
ある。As is clear from this figure, the internal electrode 2
Is sufficiently exposed from the side end surface due to the formation of the alloy 5 with the metal film 4b, so that the internal electrode 2 and the external electrode 3 are surely electrically connected. In the embodiment of the present invention, Ag-Pd system and Pd are used for the internal electrode 2 and Ag is used for the second metal film 4b. Is also good. The diffusion coefficient will be described here. Generally, the diffusion coefficient of a metal is given by the following equation. D = D 0 exp (−Q / RT) D: Diffusion coefficient (cm 2 / sec) D 0 : Diffusion frequency term (cm 2 / sec) Q: Activation energy (kcal / mol) R: Gas constant ( 1.986 cal / K · mol) T: Absolute temperature (K) However, the diffusion frequency term D 0 and the activation energy Q are the numerical values peculiar to the metal material determined by the self-diffusion experiment.
【００２０】本発明で使用されたＡｇ，Ｐｄについて拡
散係数を計算すると、Ａｇ；Ｄ0=0.395(cm2/sec)，Ｑ=4
4.09(kcal/mol)であり、Ｐｄ；Ｄ0=0.205(cm2/sec)，Ｑ
=63.6(kcal/mol)であり、Ｔ=1125Kとして式（１）にそ
れぞれ代入すると拡散係数が得られる。ＡｇはＤ＝0.38
7(cm2/sec)、ＰｄはＤ＝0.199(cm2/sec)となりＡｇの拡
散係数がＰｄより大きいことが判る。従って、上記の式
で算出される拡散係数の値を参照に適宜金属材料を選択
することができる。Calculating diffusion coefficients for Ag and Pd used in the present invention, Ag; D 0 = 0.395 (cm 2 / sec), Q = 4
4.09 (kcal / mol), Pd; D 0 = 0.205 (cm 2 / sec), Q
= 63.6 (kcal / mol), and the diffusion coefficient is obtained by substituting T = 1125K into the equation (1). Ag is D = 0.38
7 (cm 2 / sec), Pd is D = 0.199 (cm 2 / sec), and it can be seen that the diffusion coefficient of Ag is larger than Pd. Therefore, the metal material can be appropriately selected with reference to the value of the diffusion coefficient calculated by the above formula.
【００２１】次に、本願発明により形成された積層セラ
ミックコンデンサと、従来のＡｇ粉末とＺｒＯ2粉末を
利用して形成された積層セラミックコンデンサの外部電
極の密着強度に関する比較実験を行った。この実験で
は、図３（ａ）に示すように、薄本体片１に形成された
薄膜の外部電極３に先端に円形の取付部２１を有するリ
ード線２０を半田付けし、リード線２１を両端側から引
張り、外部電極３が剥がれるときの引張り強度を測定す
ることで密着強度を測定した。Next, a comparative experiment was conducted on the adhesion strength of the external electrodes of the laminated ceramic capacitor formed according to the present invention and the conventional laminated ceramic capacitor formed using Ag powder and ZrO 2 powder. In this experiment, as shown in FIG. 3A, a lead wire 20 having a circular attachment portion 21 at the tip is soldered to the thin film external electrode 3 formed on the thin body piece 1, and the lead wire 21 is attached at both ends. The adhesion strength was measured by pulling from the side and measuring the tensile strength when the external electrode 3 was peeled off.
【００２２】その結果を、図３（ｂ）のグラフに表示し
た。このグラフで、直線は強度のばらつきを示し、丸印
はその平均値を示している。このグラフからも明らかな
ように、本願発明の方法で形成された外部電極の密着強
度が、従来方法で形成された外部電極の密着強度に比
べ、ばらつきが少なく、しかもその引張強度が大きくな
るといえる。The results are shown in the graph of FIG. 3 (b). In this graph, the straight line shows the variation in strength, and the circles show the average value. As is clear from this graph, it can be said that the adhesion strength of the external electrode formed by the method of the present invention has less variation compared to the adhesion strength of the external electrode formed by the conventional method, and the tensile strength thereof becomes large. .
【００２３】[0023]
【発明の効果】以上、説明したように本発明による積層
セラミックコンデンサの外部電極の形成方法によれば、
セラミックに対して密着強度の高い第一金属膜を形成し
た後、内部電極の材料と異なる拡散係数を持つ第二金属
膜を形成して熱処理を施すと、この第二金属膜が第一金
属膜を通過して内部電極側に拡散が起こり、内部電極と
第二金属膜との間に合金が形成される。その結果、内部
電極が実質的に延長され、本体片の側端面から十分露出
されて内部電極と外部電極との接続がより確実になると
ともに、第一金属膜により密着強度の高い外部電極を形
成することができ、静電容量の損失、誘電正接（ｔａｎ
δ）の増大、密着強度の低下等の問題を解決することが
できる。As described above, according to the method of forming the external electrodes of the laminated ceramic capacitor of the present invention,
After forming the first metal film having high adhesion strength to the ceramic, forming a second metal film having a diffusion coefficient different from that of the material of the internal electrodes and performing heat treatment, the second metal film becomes the first metal film. Through which the diffusion occurs on the internal electrode side, and an alloy is formed between the internal electrode and the second metal film. As a result, the internal electrode is substantially extended and fully exposed from the side end surface of the main body piece to more securely connect the internal electrode and the external electrode, and the external electrode having high adhesion strength is formed by the first metal film. Can be the capacitance loss, loss tangent (tan
Problems such as an increase in δ) and a decrease in adhesion strength can be solved.
【００２４】特に、金属膜の拡散係数が内部電極材料よ
り大きいので、内部電極に金属膜が第一電極層を通過し
て入り込み、内部電極材料と金属膜との間に合金が形成
されて内部電極の実質的に長くなり本体片の側端面から
確実に露出するようになる。In particular, since the diffusion coefficient of the metal film is larger than that of the internal electrode material, the metal film enters the internal electrode through the first electrode layer , and an alloy is formed between the internal electrode material and the metal film to form an internal electrode. The electrode is substantially lengthened and it is surely exposed from the side end surface of the main body piece.
【図面の簡単な説明】[Brief description of drawings]
【図１】本発明の積層セラミックコンデンサの製造工程
の一部を示す説明図。FIG. 1 is an explanatory view showing a part of a manufacturing process of a monolithic ceramic capacitor of the present invention.
【図２】本発明の積層セラミックコンデンサの製造工程
の一部を示す説明図。FIG. 2 is an explanatory view showing a part of the manufacturing process of the multilayer ceramic capacitor of the present invention.
【図３】本発明により形成された外部電極の密着強度を
示すグラフ。FIG. 3 is a graph showing the adhesion strength of external electrodes formed according to the present invention.
【図４】従来の積層セラミックコンデンサを示す断面
図。FIG. 4 is a sectional view showing a conventional monolithic ceramic capacitor.
【図５】従来の積層セラミックコンデンサの製造方法を
示す断面図。FIG. 5 is a sectional view showing a method for manufacturing a conventional monolithic ceramic capacitor.
１ 本体片 ２ 内部電極 ３ 外部電極 ４ａ 第一金属膜 ４ｂ 第二金属膜 ５ 合金部 1 body piece 2 internal electrodes 3 external electrodes 4a First metal film 4b Second metal film 5 alloy department
フロントページの続き (58)調査した分野(Int.Cl.7，ＤＢ名) H01G 4/00 - 17/00 Continuation of front page (58) Fields surveyed (Int.Cl. 7 , DB name) H01G 4/00-17/00
Claims (2)
の内部電極を配設し前記本体片から内部電極を露出させ
た後、前記本体片の側端面にセラミックに対し密着強度
の高い第一金属膜と内部電極の材料と異なる拡散係数を
持つ第二金属膜をこの順で形成し熱処理を施した後、前
記内部電極と導通する外部電極を設けることを特徴とす
る積層セラミックコンデンサの外部電極の形成方法。1. A first body having a high adhesion strength to the ceramic on a side end surface of the body piece after a plurality of inner electrodes are provided inside the body piece made of ceramic to expose the inner electrodes from the body piece. A second metal film having a diffusion coefficient different from that of the materials of the metal film and the internal electrode is formed in this order, heat-treated, and then an external electrode is provided which is electrically connected to the internal electrode. Forming method.
の材料より大きいことを特徴とする請求項１記載の積層
セラミックコンデンサの外部電極の形成方法。2. The method for forming an external electrode of a monolithic ceramic capacitor according to claim 1, wherein a diffusion coefficient of the second metal film is larger than a material of the internal electrode.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28706096A JP3524298B2 (en) | 1996-10-29 | 1996-10-29 | Method of forming external electrodes of multilayer ceramic capacitor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28706096A JP3524298B2 (en) | 1996-10-29 | 1996-10-29 | Method of forming external electrodes of multilayer ceramic capacitor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH10135064A JPH10135064A (en) | 1998-05-22 |
| JP3524298B2 true JP3524298B2 (en) | 2004-05-10 |
Family
ID=17712541
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP28706096A Expired - Fee Related JP3524298B2 (en) | 1996-10-29 | 1996-10-29 | Method of forming external electrodes of multilayer ceramic capacitor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3524298B2 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP5998785B2 (en) * | 2012-09-19 | 2016-09-28 | Tdk株式会社 | Laminated electronic components |
| CN107112149A (en) | 2015-01-30 | 2017-08-29 | 株式会社村田制作所 | Electrical storage device and its manufacture method |
-
1996
- 1996-10-29 JP JP28706096A patent/JP3524298B2/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| JPH10135064A (en) | 1998-05-22 |
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