JP4487613B2 - Multilayer ceramic electronic components - Google Patents

Description

  The present invention relates to a multilayer ceramic electronic component, and more particularly to a multilayer ceramic electronic component such as a multilayer ceramic capacitor.

  FIG. 8 is an illustrative view showing a multilayer ceramic capacitor as an example of a conventional multilayer ceramic electronic component. The multilayer ceramic capacitor 1 includes a multilayer body 2. The multilayer body 2 has a configuration in which a plurality of dielectric ceramic layers 3 and internal electrode layers 4 are laminated. In the stacked body 2, the adjacent internal electrode layers 4 are alternately drawn out to the opposing side surfaces of the stacked body 2. An external electrode 5 is formed on the side surface of the laminate 2 from which the internal electrode layer 4 is drawn. The external electrode 5 is formed so as to go around from the opposite side surface of the multilayer body 2 toward the adjacent surface. Adjacent internal electrode layers 4 are alternately connected to these external electrodes 5. Accordingly, a capacitance is formed between the two external electrodes 5.

  When such a multilayer ceramic capacitor 1 is mounted on a circuit board or the like, cracks may occur in the multilayer body 2 when mechanical stress is applied to the multilayer ceramic capacitor 1. The stress applied to the multilayer ceramic capacitor 1 is concentrated on the boundary portion between the exposed portion of the multilayer body 2 and the edge portion of the external electrode 5. Therefore, as shown in FIG. 9, the crack 6 is generated from the boundary portion between the exposed portion of the multilayer body 2 and the external electrode 5 toward the lamination direction of the multilayer body 2. When the crack 6 occurs, a short circuit occurs between the plurality of internal electrode layers 4. Since the adjacent internal electrode layers 4 are connected to different external electrodes 5, there is a potential difference between the adjacent internal electrode layers 4, and if a short circuit occurs between the internal electrode layers 4, the circuit board may be damaged. .

  Therefore, as shown in FIG. 10, the internal electrode layer 4 connected to one of the external electrodes 5 has a position corresponding to the boundary portion between the exposed portion of the multilayer body 2 and the external electrode 5 on the opposing external electrode 5 side. The structure which does not reach to is disclosed. By adopting such a configuration, even if a crack occurs in the laminate 2, only the internal electrode layer 4 connected to the same external electrode 5 is short-circuited to be in an open state, thereby preventing damage to the circuit board. (For example, refer to Patent Document 1).

JP-A-8-45777

  However, the multilayer ceramic capacitor as shown in FIG. 10 has a structure in which the adjacent internal electrode layers do not oppose each other at the position corresponding to the wraparound portion of the external electrode, so that the opposing area of the internal electrode layer becomes small and the static electricity obtained can be obtained. The electric capacity becomes small.

  Therefore, a main object of the present invention is to provide a multilayer ceramic electronic component capable of obtaining a large capacitance without causing a short circuit in an internal electrode layer having a potential difference even when a crack occurs in the multilayer body. is there.

The present invention relates to a laminate in which a plurality of ceramic layers and internal electrode layers are laminated, and two external electrodes formed so as to wrap around from the side surfaces on one end side and the other end side in the longitudinal direction of the laminate. wherein the door, one of the adjacent internal electrode layers is connected to one external electrodes by exposing the one longitudinal end of the stack, the position and two external corresponds to the exposed portion of the stack It is formed over both positions corresponding to the wraparound portion of the electrode, and the other of the adjacent internal electrode layers is connected to the other external electrode by being exposed to the other end side in the longitudinal direction of the stacked body, and The internal electrode layer formed over both the position corresponding to the exposed portion and the position corresponding to the wraparound portion of the two external electrodes and connected to one of the external electrodes is a boundary between the exposed portion of the laminate and the two external electrodes. portion By a Oite lack portion into two positions in the longitudinal direction of both ends of the corresponding stack and a connecting portion is formed, a connecting structure at the junction of the two positions, the other external electrode The connected internal electrode layers are formed by forming a lacking portion and a connecting portion at two positions on both ends in the longitudinal direction of the laminate corresponding to the boundary portion between the exposed portion of the laminate and the two external electrodes. In the laminating direction of the ceramic layer and the internal electrode layer at a position corresponding to the boundary portion between the exposed portion of the laminated body and the wraparound portion of the one external electrode, the structure is connected by the connecting portion at two positions. The connecting portion of the internal electrode layer connected to the external electrode and the connecting portion of the internal electrode layer connected to the other external electrode are arranged so as not to overlap each other, and the exposed portion of the laminate and the other external electrode Boundary with wraparound In the stacking direction of the ceramic layer and the internal electrode layer at a position corresponding to the minute, the connection portion of the internal electrode layer connected to one external electrode and the connection portion of the internal electrode layer connected to the other external electrode overlap each other. A multilayer ceramic electronic component, wherein the multilayer ceramic electronic component is arranged so as not to match .

By forming the internal electrode layer over both the position corresponding to the exposed portion of the multilayer body and the position corresponding to the wraparound portion of the external electrode, the facing area of the internal electrode layer in the multilayer body can be increased. Further, at the position corresponding to the boundary portion between the exposed portion of the laminate and the external electrode, the connecting portion of the internal electrode layer connected to the different external electrode does not overlap in the stacking direction of the ceramic layer and the internal electrode layer. Therefore, even if a crack is generated in the stacking direction in this portion, a short circuit does not occur in the internal electrode layer having a potential difference.
In such a multilayer ceramic electronic component, external electrodes can be formed on opposing side surfaces of the multilayer body to form a chip-type multilayer ceramic capacitor.

  According to the present invention, at the position corresponding to the boundary portion between the exposed portion of the multilayer body and the external electrode, the connecting portion of the internal electrode layer is disposed so as not to overlap in the stacking direction, so that there is a crack in this portion. Even if it occurs, the internal electrode layers connected to different external electrodes do not short-circuit. Therefore, when the multilayer ceramic electronic component is mounted on the circuit board, it is possible to prevent the circuit board from being damaged by the internal electrode layer short circuit of the multilayer ceramic electronic component. Further, since the internal electrode layer is formed over both the position corresponding to the exposed portion of the multilayer body and the position corresponding to the wraparound portion of the external electrode, the opposing area of the internal electrode layer in the multilayer body can be increased. , Can ensure a large capacitance

  The above object, other objects, features, and advantages of the present invention will become more apparent from the following description of the best mode for carrying out the invention with reference to the drawings.

  FIG. 1 is a perspective view showing a multilayer ceramic capacitor as an example of the multilayer ceramic electronic component of the present invention, and FIG. 2 is an illustrative view showing a cross section taken along line AA of FIG. The multilayer ceramic capacitor 10 includes, for example, a rectangular parallelepiped multilayer body 12. As shown in FIG. 3, the multilayer body 12 has a configuration in which a plurality of dielectric ceramic layers 14 and internal electrode layers 16a and 16b are laminated.

  As shown in FIG. 4A, the internal electrode layer 16 a is formed so as to be drawn out to one end side in the longitudinal direction of the dielectric ceramic layer 14 and to extend toward the other end side of the dielectric ceramic layer 14. In two portions of the dielectric ceramic layer 14 spaced apart from each other in the longitudinal direction by a certain distance, a lacking portion 18a is formed in the internal electrode layer 16a. The lacking portion 18a is formed from one side in the width direction of the internal electrode layer 16a toward the other side, and the connecting portion 20a is formed on the other side in the width direction of the internal electrode layer 16a.

  Further, as shown in FIG. 4B, the internal electrode layer 16 b is formed so as to be drawn out to the other end side in the longitudinal direction of the dielectric ceramic layer 14 and to extend toward one end side of the dielectric ceramic layer 14. The In two portions of the dielectric ceramic layer 14 that are spaced apart from both ends in the longitudinal direction by a certain distance, a lacking portion 18b is formed in the internal electrode layer 16b. The lacking portion 18b is formed from the other side in the width direction of the internal electrode layer 16b toward one side, and the connecting portion 20b is formed on one side in the width direction of the internal electrode layer 16b. These lacking portions 18a and 18b are formed at positions where they overlap each other when the dielectric ceramic layers 14 shown in FIGS. 4A and 4B are overlapped. However, when the dielectric ceramic layers 14 shown in FIGS. 4A and 4B are overlapped, the connecting portions 20 a and 20 b are arranged on the opposite side of the dielectric ceramic layer 14 in the width direction.

  The dielectric ceramic layers 14 having the internal electrode layers 16a and 16b are alternately laminated, and the dielectric ceramic layers 14 without the internal electrode layers are laminated so as to sandwich the dielectric ceramic layers 14 therebetween. The laminated body 12 is formed by laminating and integrating the dielectric ceramic layer 14 and the internal electrode layers 16a and 16b. Therefore, the lacking portions 18 a and 18 b of the internal electrode layers 16 a and 16 b are arranged linearly in the stacking direction of the stacked body 12. Further, the connecting portions 20a and 20b of the internal electrode layers 16a and 16b are formed at corresponding positions in the width direction of the stacked body 12, and are arranged so as not to overlap in the stacking direction. Further, one internal electrode layer 16 a is drawn out to one end side in the longitudinal direction of the laminate 12, and the other internal electrode layer 16 b is drawn out to the other end side in the longitudinal direction of the laminate 12.

  External electrodes 22a and 22b are formed on opposite side surfaces of the stacked body 12 from which the internal electrode layers 16a and 16b are drawn. The external electrodes 22a and 22b are formed so as to wrap around from the opposite side surfaces of the multilayer body 12 to the adjacent surfaces. In the wraparound portions of the external electrodes 22a and 22b, the lacking portions 18a and 18b of the internal electrode layers 16a and 16b and the connecting portions 20a and 20b are located at positions corresponding to the boundary portions between the exposed portions of the multilayer body 12 and the external electrodes 22a and 22b. Is placed. The external electrodes 22a and 22b are formed, for example, by baking an electrode paste such as Ag or Cu. If necessary, in order to improve the Ni plating film and solderability to prevent solder erosion. An Sn plating film or the like may be formed.

  In order to produce the multilayer ceramic capacitor 10, a ceramic green sheet is formed using a dielectric ceramic material. On this ceramic green sheet, a conductor paste is printed in the shape of the internal electrode layers 16a and 16b to form a conductor pattern. A laminate 12 is obtained by laminating and pressing a ceramic green sheet on which a conductor pattern is formed and a ceramic green sheet on which a conductor pattern is not formed, and firing the laminate. Then, the external electrodes 22a and 22b are formed by applying and baking an electrode paste on the side surface of the laminate 12 where the internal electrode layers 16a and 16b are exposed. Furthermore, if necessary, a Ni plating film is formed on the external electrodes 22a and 22b, and a Sn plating film is further formed.

  The multilayer ceramic capacitor 10 is mounted on a circuit board or the like. At this time, when mechanical stress is applied to the multilayer ceramic capacitor 10, the stress concentrates on the boundary portion between the exposed portion of the multilayer body 12 and the external electrodes 22a and 22b. When stress is applied to the boundary portion between the exposed portion of the multilayer body 12 and the external electrodes 22a and 22b, a crack 24 may occur from the boundary portion in the stacking direction of the multilayer body 12, as shown in FIG. is there.

  However, since the lacking portions 18a and 18b of the internal electrode layers 16a and 16b are arranged at positions corresponding to the boundary portions between the exposed portions of the multilayer body 12 and the external electrodes 22a and 22b, the positions of the lacking portions 18a and 18b are arranged. Even if the crack 24 occurs, the internal electrode layers 22a and 22b are not short-circuited. Further, even if a crack 24 occurs in the portion where the connecting portions 20a and 20b of the internal electrode layers 16a and 16b are arranged, the connecting portions 20a and 20b do not overlap in the stacking direction of the stacked body 12, Only the parts 20a or the connecting parts 20b are short-circuited. Therefore, the internal electrode layer 16a and the internal electrode layer 16b connected to the different external electrodes 22a and 22b are not short-circuited, only the internal electrode layer 16a or 16b having the same potential is short-circuited, and the circuit board is damaged. Etc. can be prevented.

  Furthermore, in this multilayer ceramic capacitor 10, the internal electrode layers 16a and 16b are connected via the connecting portions 20a and 20b over the position corresponding to the exposed portion of the multilayer body 12 and the position corresponding to the wraparound portion of the external electrodes 22a and 22b. Opposite. Therefore, the facing area of the internal electrode layers 16 a and 16 b can be increased in the multilayer body 12, which is larger than the multilayer ceramic capacitor in which the internal electrode layer is opposed only at a position corresponding to the exposed portion of the multilayer body 12. Capacitance can be secured.

  If the connecting portions 20a and 20b of the two internal electrode layers 16a and 16b do not overlap in the stacking direction of the stacked body 12, the above-described effects can be obtained. Accordingly, as shown in FIGS. 6A and 6B, the lacking portions 18a and 18b may be short. However, in this case, the lacking portions 18a and 18b need to be formed to have a length exceeding the central portion in the width direction of the dielectric ceramic layer 14 so that the connecting portions 20a and 20b do not overlap. Further, as shown in FIGS. 7A and 7B, the internal electrode layers 16a and 20b are connected by a plurality of connecting portions 20a and 20b at positions corresponding to the boundary portions between the exposed portions of the laminate 12 and the external electrodes 22a and 22b. 16b may be connected. In this case, the connecting portions 20 a and 20 b of the adjacent internal electrode layers 16 a and 16 b are formed at positions that do not overlap in the stacking direction of the stacked body 12.

  In order to produce a multilayer ceramic capacitor having a size of 3.2 mm × 2.5 mm, a ceramic green sheet was formed using a barium titanate-based material. The thickness of the ceramic green sheet is 4.2 μm. A conductive pattern for the internal electrode layer having a shape as shown in FIGS. 4A and 4B was formed on the ceramic green sheet using a conductive paste mainly composed of Ni.

  As for the size of the conductor pattern, the length in the longitudinal direction is 2.4 mm, and the length in the width direction is 2.0 mm. Further, the gap between the end of the ceramic green sheet in the longitudinal direction and the end of the conductor pattern is 0.1 mm, and the gap between the end of the ceramic green sheet in the width direction and the conductor pattern is 0.2 mm. The thickness of the conductor pattern is 1 μm. Further, the width of the lacking part is 200 μm, and the width of the connecting part is 200 μm. Note that the positions where the missing portion and the connecting portion are formed correspond to the boundary portion between the exposed portion of the multilayer body and the external electrode when the multilayer ceramic capacitor is manufactured.

  As a comparative example, a multilayer ceramic capacitor having internal electrode layers facing each other only at a position corresponding to the exposed portion of the multilayer body was produced as shown in FIG. For this purpose, a conductor pattern for forming an internal electrode layer having no missing portion was formed on the ceramic green sheet. As for the size of the conductor pattern, the length in the longitudinal direction of the internal electrode layer is 1.7 mm, and the length in the width direction is 2.0 mm. Further, the gap between the end portion of the ceramic green sheet in the longitudinal direction and the end portion of the conductor pattern is 0.65 mm, and the gap between the end portion in the width direction of the ceramic green sheet and the end portion of the conductor pattern is 0. The thickness of the conductor pattern is 1 μm.

  330 ceramic green sheets on which these conductor patterns were formed were laminated, ceramic green sheets on which no conductor patterns were formed were laminated on both sides, and pressed and fired to produce a laminate. External electrodes were formed on the opposite side surfaces of the obtained laminate so as to be connected to the internal electrode layer. The boundary portion between the exposed portion of the laminate and the end portion of the external electrode is a position corresponding to the lacking portion and the connecting portion of the internal electrode layer of this embodiment. In the multilayer ceramic capacitor of the comparative example, the internal electrode layers face each other only at a position corresponding to the exposed portion of the multilayer body.

  In the multilayer ceramic capacitors of these examples and comparative examples, even if a crack occurs in the stacking direction at a position corresponding to the boundary portion between the exposed portion of the multilayer body and the end portion of the external electrode, it is connected to a different external electrode. No short circuit occurred between the internal electrode layers. However, when the capacitance was measured, it was 4.0 μF in the multilayer ceramic capacitor of the comparative example, whereas it was 5.7 μm in the multilayer ceramic capacitor of the example, which was about 40% of the comparative example. The capacitance increased.

  Thus, even for multilayer ceramic capacitors having the same outer diameter, a large capacitance can be obtained by increasing the opposing area of the internal electrode layers. Furthermore, at the position corresponding to the boundary portion between the exposed portion of the multilayer body and the end portion of the external electrode, the internal electrode layer is formed with a missing portion and arranged so that the connecting portions do not overlap in the stacking direction. Can prevent short circuit.

1 is a perspective view showing a multilayer ceramic capacitor as an example of a multilayer ceramic electronic component of the present invention. It is an illustration figure which shows the cross section in line AA of FIG. It is a disassembled perspective view of the laminated body used for the laminated ceramic capacitor shown in FIG. (A) (B) is a top view which shows the dielectric ceramic layer and internal electrode layer which are used for the laminated body shown in FIG. FIG. 2 is an illustrative view showing a state in which a crack is generated in the multilayer ceramic capacitor shown in FIG. 1. (A) (B) is an illustration figure showing other examples of a dielectric ceramic layer and an internal electrode layer. (A) and (B) are illustrative views showing still another example of the dielectric ceramic layer and the internal electrode layer. It is an illustration figure which shows the internal structure of the multilayer ceramic capacitor as an example of the conventional multilayer ceramic electronic component. FIG. 9 is an illustrative view showing a state in which a crack has occurred in the conventional multilayer ceramic capacitor shown in FIG. 8. FIG. 9 is an illustrative view showing a conventional multilayer ceramic capacitor that has been considered to solve the problems of the multilayer ceramic capacitor shown in FIG. 8.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Multilayer ceramic capacitor 12 Laminated body 14 Dielectric ceramic layer 16a, 16b Internal electrode layer 18a, 18b Lack part 20a, 20b Connection part 22a, 22b External electrode 24 Crack

Claims (1)

A laminated body in which a plurality of ceramic layers and internal electrode layers are laminated, and two external electrodes formed to wrap around from the side surface on one end side and the other end side in the longitudinal direction of the laminated body,
One of the adjacent the inner electrode layer, wherein is connected to one of said external electrodes by exposing the one longitudinal end of the stack, the position and the two corresponding to the exposed portion of the laminate the Formed over both positions corresponding to the wraparound portion of the external electrode,
The other of the adjacent internal electrode layers is connected to the other external electrode by being exposed to the other end side in the longitudinal direction of the multilayer body, and the position corresponding to the exposed portion of the multilayer body and the two of the two Formed over both positions corresponding to the wraparound portion of the external electrode,
The one of the external electrodes connected to the internal electrode layers, Oite into two positions in the longitudinal direction of both ends of the laminate corresponding to the boundary portion between the exposed portion and two of said external electrodes of the laminate By forming the lacking part and the connecting part, it has a structure connected by the connecting part in two positions ,
The internal electrode layer connected to the other external electrode has a missing portion at two positions on both ends in the longitudinal direction of the multilayer body corresponding to a boundary portion between the exposed portion of the multilayer body and the two external electrodes. And the connecting portion is formed, and has a structure connected by the connecting portion at two positions,
The internal electrode layer connected to one of the external electrodes in the stacking direction of the ceramic layer and the internal electrode layer at a position corresponding to a boundary portion between the exposed portion of the laminate and the wraparound portion of one of the external electrodes The connecting portion and the connecting portion of the internal electrode layer connected to the other external electrode are arranged so as not to overlap each other .
The internal electrode layer connected to one of the external electrodes in the stacking direction of the ceramic layer and the internal electrode layer at a position corresponding to a boundary portion between the exposed portion of the multilayer body and the wraparound portion of the other external electrode A multilayer ceramic electronic component , wherein the connecting portion of the internal electrode layer and the connecting portion of the internal electrode layer connected to the other external electrode are arranged so as not to overlap each other .

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