JP5769487B2 - Capacitor - Google Patents

Description

  The present invention relates to a capacitor.

  In the conventional capacitor, when the external electrode is formed from the end surface of the multilayer body to both side surfaces by plating, the end portion of the internal electrode is exposed from the end surface of the multilayer body. In addition, the end portions of the dummy electrodes arranged on both sides of the internal electrode are exposed from the end surface to the side surface of the multilayer body (see Patent Document 1). Then, external electrodes are formed by plating on the exposed portions of the internal electrodes and the dummy electrodes.

  Thus, by separating the internal electrode and the dummy electrode in the width direction of the laminated body, the internal electrode paste by the printing mask in the vicinity of the connection portion between the internal electrode and the dummy electrode when they are connected It can prevent fading at the time of application.

JP 2003-282356 A

  However, on the end face of the capacitor laminate as shown in Patent Document 1, the gap between the internal electrode and the dummy electrode is identical between the dielectric layers provided with the internal electrodes adjacent in the lamination direction. Therefore, when the external electrode is formed by plating, the exposed end portion of the internal electrode and the exposed end portion of the dummy electrode are difficult to be connected by the external electrode formed by plating on the end face, and the external electrode is easily disconnected.

The capacitor of the present invention includes a laminate in which a plurality of dielectric layers are laminated, an internal electrode provided between the dielectric layers so as to face each other with the dielectric layer interposed therebetween, and the internal electrode is electrically An external electrode provided so as to cover an end portion of the multilayer body, and an end portion side of the internal electrode, on at least one side of both side surfaces of the multilayer body, from the internal electrode A dummy electrode that is spaced apart and is exposed from the side surface and the end surface, and is electrically connected to the external electrode, and a gap between the internal electrode and the dummy electrode on the end surface is the stacking direction The internal electrodes do not coincide with each other between the dielectric layers provided with adjacent internal electrodes , and the internal electrodes are drawn to the end face from the capacitance forming portion and the capacitance forming portion facing each other through the dielectric layer. With drawer section Has, the lead portion is unevenly distributed on one side surface
The dummy electrode is arranged on the other side surface side .

According to the capacitor of the present invention, the laminated body in which a plurality of dielectric layers are laminated, the internal electrode provided between the dielectric layers so as to face each other through the dielectric layer, and the internal electrode are electrically connected. The external electrode provided to cover the end of the laminate and the end of the internal electrode, and disposed on at least one side of the both sides of the laminate apart from the internal electrode And a dummy electrode that is exposed from the side surface and the end surface and is electrically connected to the external electrode, and an internal electrode adjacent to the stacking direction is provided in the gap between the internal electrode and the dummy electrode at the end surface. The internal electrodes do not match between the dielectric layers, and the internal electrode has a capacitance forming portion facing each other through the dielectric layer, and a lead portion drawn from the capacitance formation portion to the end face. Is unevenly distributed on one side Are disposed, the dummy electrodes, since it is located on the other side surface side, in the direction of the upper and lower gap between the inner electrode and the dummy electrode in the end face, the internal electrodes or the dummy electrodes adjoin in the stacking direction is located It will be. Therefore, the electrode portion formed by plating on the internal electrode or the dummy electrode covers the gap between the internal electrode and the dummy electrode. Therefore, the external electrode can be prevented from being interrupted between the internal electrode and the dummy electrode.

It is a perspective view which shows an example of embodiment of the capacitor | condenser of this invention. (A) is a top view of one first internal electrode in the capacitor of the present invention, and (b) is a top view of the other first internal electrode. It is an end view of the multilayer body of the capacitor of the present invention. (A) is an enlarged view of the end surface of the multilayer body in an example of the capacitor of the present invention, and (b) and (c) are enlarged views of the end surface of the multilayer body in another example of the capacitor of the present invention. It is a cross-sectional view of the capacitor of the present invention. (A) is a top view of another example of one first internal electrode in the capacitor of the present invention, and (b) is a top view of another example of the other first internal electrode. (A) is a top view of another example of one first internal electrode in the capacitor of the present invention, and (b) is a top view of another example of the other first internal electrode. (A) is a top view of another example of one first internal electrode in the capacitor of the present invention, and (b) is a top view of another example of the other first internal electrode. (A) is a top view of another example of one first internal electrode in the capacitor of the present invention, and (b) is a top view of another example of the other first internal electrode.

  Hereinafter, an example of an embodiment of a capacitor of the present invention will be described in detail with reference to the drawings. The capacitor 1 shown in FIGS. 1 to 5 includes a multilayer body 2, an internal electrode 3, and an external electrode 4 as a basic configuration.

  The laminate 2 is formed by laminating a plurality of dielectric layers 5. The laminate 2 is a rectangular parallelepiped dielectric block in which, for example, 20 to 2000 layers of a plurality of rectangular dielectric layers 5 formed to have a thickness of 1 to 2 μm per layer are laminated. The laminated body 2 includes a first main surface 2a (upper surface) and a second main surface (lower surface) 2b that face each other, and a first side surface 2c that faces each other, as shown in FIGS. It is formed in a substantially rectangular parallelepiped shape having a second side surface 2d, and a first end surface 2e and a second end surface 2f facing each other. Moreover, the dimension of the laminated body 2 makes the length of the long side of the laminated body 2 into 0.4-3.2 mm, for example, and makes the length of the short side of the laminated body 2 into 0.2-1.6 mm, for example.

Examples of the material for the dielectric layer 5 include BaTiO ₃ , CaTiO ₃ , SrTiO _{3, and} CaZrO ₃ . As another _example, BaTiO _3, CaTiO 3, and SrTiO ₃ or CaZrO ₃ as a main component, Mn compound, Fe compound, Cr compounds, Co compounds, or may be Ni compound or the like is added .

  As shown in FIG. 5, the first external electrode 4a and the second external electrode 4b are connected to the first internal electrodes 3a, 3b and the second internal electrode 3c, respectively. The first external electrode 4 a and the second external electrode 4 b are provided on the surface of the multilayer body 2. In the following description, when the term “external electrode 4” is simply used, it means both the first external electrode 4a and the second external electrode 4b.

  In the example shown in FIG. 5, the first external electrode 4 a and the second external electrode 4 b are provided at the end of the multilayer body 2. The external electrode 4 has a thickness of 5 to 50 μm. The external electrode 4 is electrically connected to an electrode pad on the wiring board and plays a role of ensuring electrical continuity with the wiring board.

As shown in FIG. 5, the first external electrode 4a is formed on the second end face 2f. As shown in FIG. 1, the end portion of the first external electrode 4a reaches the first and second side surfaces 2c and 2d. As shown in FIG. 5, the first external electrode 4a is electrically connected to each of the plurality of first internal electrodes 3a and 3b drawn to the second end face 2f.

  As shown in FIG. 5, the second external electrode 4b is formed on the first end face 2e. As shown in FIG. 1, the end portion of the second external electrode 4b reaches the first and second side surfaces 2c and 2d. As shown in FIG. 5, the second external electrode 4b is electrically connected to each of the plurality of second internal electrodes 3c drawn to the first end face 2e.

  For example, one or a plurality of plating films such as a Ni plating film and a Sn plating film may be formed on the surface of the external electrode 4 in order to protect the external electrode 4 and improve mountability. preferable. For example, a laminate of a Ni plating film and a Sn plating film may be formed on the surface of the external electrode 4.

  The method for bonding the external electrode 4 to the wiring board is not particularly limited. For example, an appropriate joining member such as high-temperature solder such as Sn-Sb-based high-temperature solder, Sb-Pb eutectic solder, Sn-Ag-Cu-based Pb-free solder, Sn-Cu-based Pb-free solder, or resin containing conductive fine particles The external electrode 4 and the wiring board can be joined using

  The first internal electrodes 3a and 3b and the second internal electrode 3c are provided between the dielectric layers 5 so as to face each other with the dielectric layer 5 interposed therebetween. In the following description, the expression “internal electrode 3” means both the first internal electrodes 3a and 3b and the second internal electrode 3c.

  In the example illustrated in FIG. 5, a plurality of first internal electrodes 3 a and 3 b and a plurality of second internal electrodes 3 c are alternately arranged between the dielectric layers 5 of the stacked body 2.

  As shown in FIG. 2A, one end of the plurality of first internal electrodes 3a and 3b is drawn out to the second end face 2f. The first internal electrodes 3a and 3b do not reach the first and second side surfaces 2c and 2d.

  As shown in FIG. 5, one end portion of the plurality of second internal electrodes 3c is drawn out to the first end surface 2e. The second internal electrode 3c does not reach the first and second side surfaces 2c and 2d.

  The internal electrode 3 is formed between 20 and 2000 layers between the dielectric layers 5 of the laminate 2. Examples of the material of the internal electrode 3 include metals such as Ni, Cu, Ag, Pd, and Au, or alloys such as an Ag—Pd alloy containing one or more of these metals. All the internal electrodes 3 are preferably formed of the same metal or alloy.

  The overall dimensions of the internal electrode 3 are, for example, 0.39 to 3.1 mm in the long side direction of the multilayer body 2 in FIG. 2A, and are 0.19 to 1.5 mm, for example, in the short side direction of the multilayer body 2. The thickness of the internal electrode 3 is not particularly limited. The thickness of the internal electrode 3 is, for example, about 0.3 to 2 μm.

In the example shown in FIG. 2 and FIG. 3, the first internal electrode 3a is unevenly distributed on one side surface 2c, and is connected to the same external electrode 4a, and is unevenly distributed on the other side surface 2d. The other first internal electrodes 3b arranged in this manner are alternately arranged in the stacking direction.

The dummy electrode 6 is disposed on the end portion side of the internal electrode 3 and on at least one side of the both side surfaces 2c and 2d of the multilayer body 2 while being spaced apart from the internal electrode 3 and exposed from the side surface and the end surface. It is electrically connected to the external electrode 4. In the example shown in FIGS. 2A and 2B, a dummy electrode 6 is disposed between the dielectric layers 5 on the side surface opposite to the side where the first internal electrodes 3a are unevenly distributed.

The size of the dummy electrode 6 is, for example, 0.1 in the long side direction of the multilayer body 2 in FIGS.
˜1 mm, for example, 0.05 to 0.5 mm in the short side direction of the laminate 2. The thickness of the dummy electrode 6 is not particularly limited. The thickness of the dummy electrode 6 may be, for example, about 0.3 to 2 μm.

In the example shown in FIG. 2A, the dummy electrode 6 is disposed on the side surface 2d of the multilayer body 2 away from the first internal electrode 3a, and is exposed from the side surface 2d and the end surface 2f. And electrically connected to the external electrode 4a. In the example shown in FIG. 2B, the dummy electrode 6 is disposed on the side surface 2c of the multilayer body 2 away from the first internal electrode 3a, and is exposed from the side surface 2c and the end surface 2f. It is electrically connected to the external electrode 4a.

With the configuration of the first internal electrodes 3a and 3b and the dummy electrode 6 as described above, the end surface 2f of the multilayer body 2 is arranged on one side surface of the end surface 2f of the multilayer body 2 as in the example shown in FIG. The first internal electrodes 3a that are unevenly distributed and the first internal electrodes 3b that are unevenly distributed on the other side surface side are alternately arranged in the stacking direction, and are opposite to the side where the first internal electrodes 3a and 3b are unevenly distributed. The dummy electrode 6 is arranged on the side surface side.

Therefore, the gap A between the first internal electrodes 3a, 3b and the dummy electrode 6 on the end face 2f does not match between the dielectric layers 5 provided with the first internal electrode electrodes 3a, 3b adjacent in the stacking direction. It becomes.

With such a configuration, as shown in FIG. 4A, the first internal electrode 3 on the end face 2f is formed.
The first internal electrode 3a is present at least one above and below the gap A between the a and 3b and the dummy electrode 6. Therefore, the first external electrode 4a formed by plating on the first internal electrode 3a existing at least above and below the gap A covers the gap A. Therefore, the external electrode 4a can be prevented from being interrupted by the gap A between the end portion of the internal electrode 3 and the end portion of the dummy electrode 6.

In the example shown in FIG. 3, in the central portion of the end surface 2 f, the first internal electrodes 3 a that are adjacent in the stacking direction,
Between 3b, the space | interval corresponded to the thickness of the 2nd internal electrode 3b and the dielectric material layer 5 for two layers exists. On the other hand, since there are gaps corresponding to the thicknesses of the four dielectric layers 5, the first internal electrodes 3a, and the second internal electrodes 3b for two layers between the dummy electrodes 6 adjacent in the stacking direction, Although the electrode spacing in the direction becomes wide, the thickness of the dielectric layer 5 and the internal electrode 3 is, for example, 0.3 to 3 per layer.
Only 2 μm. Therefore, when forming the external electrode 4 by plating, the external electrode 4a can be formed without interruption between the upper and lower dummy electrodes 6.

In the example shown in FIG. 3, as shown in FIG. 4A, the right end of the first internal electrode 3a,
The left end of the dummy electrode 6 coincides with the stacking direction. However, as shown in FIG. 4B, the right end of the first internal electrode 3a and the left end of the dummy electrode 6 do not necessarily coincide with each other in the stacking direction. Even in such a case, the right end of the first internal electrode 3a,
When the distance from the left end of the dummy electrode 6 is 10 μm or less, the effect of suppressing the disconnection of the external electrode 4a between the first internal electrode 3a and the dummy electrode 6 is obtained.

Further, as in the example shown in FIG. 4C, the end portion of the first internal electrode 3a and the end portion of the dummy electrode 6 may overlap with each other in the stacking direction. Even when the gap C exists in this way, the external electrode 4a attached to the end portion of the first internal electrode 3a by plating can sufficiently cover the gap A as in the example shown in FIG. Therefore, as a matter of course, there is an effect of suppressing discontinuity of the external electrode 4a between the first internal electrode 3a and the dummy electrode 6.

4A to 4C described above, the gap A between the first internal electrodes 3a, 3b and the dummy electrode 6 on the end face 2f is the first internal electrode electrode adjacent in the stacking direction. 3a,
There is no coincidence between the dielectric layers 5 provided with 3b. Here, “does not match” means that the whole or part of the gap A and the first internal electrode 3a (3b) overlap in the stacking direction.

  The gap A is preferably 0.07 mm or more. By sufficiently ensuring the gap A in this way, in the manufacturing process, the electrode paste to be the internal electrode 3 and the dummy electrode 6 is applied on the green sheet to be the dielectric layer using a printing mask, and the mask is applied. After the separation, the paste of both electrodes can be prevented from flowing and connecting.

  The capacitor 1 having the above configuration is manufactured by a ceramic green sheet lamination method as described below.

  Specifically, a plurality of green sheets to be the dielectric layer 5 are prepared. In this step, the ceramic green sheet is obtained by preparing a slurry-like ceramic slurry by adding and mixing a suitable organic solvent or the like to the ceramic raw material powder and the organic binder, and molding the slurry by a doctor blade method or the like. .

  Next, the internal electrode 3 and the dummy electrode 6 are formed on the green sheet. In this step, a conductor material to be a pattern of the internal electrode 3 and the dummy electrode 6 is formed on the obtained ceramic green sheet by a screen printing method or the like. In addition, the pattern of the several internal electrode 3 and the dummy electrode 6 is printed on this one green sheet so that many capacitors may be obtained from one green sheet.

  Next, after laminating and pressing a plurality of ceramic green sheets, a raw laminated body in which many pieces are integrated is produced. This laminated body is cut to obtain a raw body of the capacitor 1 as a single laminated body.

Next, the capacitor body 1 in a raw state is fired to obtain a laminate 2. In this step, for example, the laminate 2 is obtained by baking at 800 to 1050 ° C. By this step, the green sheet becomes the dielectric layer 5 and the conductive material becomes the internal electrode 3.

  Next, the external electrode 4 is formed in the exposed part from the laminated body 2 in the internal electrode 3 and the dummy electrode 6 by plating.

  The material of the external electrode 4 thus obtained may be a metal material such as silver, nickel, palladium, or an alloy thereof other than copper.

  Next, a plating layer such as a nickel (Ni) plating layer, a gold (Au) plating layer, a tin (Sn) plating layer, or a solder plating layer is formed on the surface of the obtained external electrode 4 as necessary. Capacitor 1 is obtained.

  The present invention is not limited to the embodiments described above, and various changes and improvements can be made without departing from the scope of the present invention.

  For example, the rounded portion may be formed by chamfering the laminate 2 by barrel polishing or the like. By this step, it is possible to prevent microcracks from being removed and chipped in the rounded portion of the obtained laminate 2. Furthermore, the barrel polishing has an effect of removing the surface oxide film of the metal particles and exposing the metal surface to improve the plating adhesion.

Further, for example, as in the example shown in FIGS. 6A and 6B, the first internal electrode 3 a includes a capacitance forming portion 31 that faces the second internal electrode 3 b via the dielectric layer 5, and a capacitance formation. From end 31 to end face 2f
The lead-out part 32 is arranged in a distributed manner on the one side face 2c, 2d side, and the dummy electrode 3 is placed on the other side face 2d, 2c side. It is preferable that

In this case, the capacitance forming portion 31 can be arranged at the central portion between the dielectric layers 5 in the same manner as a general capacitor, with only the lead portion 32 being unevenly distributed on either side. Therefore, when the second internal electrode 3b opposed via the dielectric layer 5 is disposed at the center between the dielectric layers 5, the positions of the first internal electrode 3a and the second internal electrode 3b are viewed in plan view. It is possible to prevent the opposite area of both from decreasing due to deviation.

  In addition, like the general capacitor, the capacitance forming portion 31 is disposed in the central portion between the dielectric layers 5 to prevent the capacitance forming portion 31 from approaching one of the side surfaces and to have an insulating property. Can be suppressed.

Further, for example, as in the example shown in FIGS. 7A and 7B, in the first internal electrode 3a, the lead-out portion 32 is pulled out to the end face 2f so as to extend obliquely with respect to the side faces 2c and 2d. Preferably it is. Generally, the internal electrode 3 is formed by filling the opening of the printing mask with the internal electrode paste by moving the squeegee along the arrangement direction of the external electrodes 4. At that time, by making the shape of the internal electrode 3 as shown in FIG. 7, the internal electrode paste is smoothly filled in the opening of the mask. Therefore, it is possible to suppress the occurrence of fading of the electrode. In the portion of the first internal electrode 3a facing the second internal electrode 3b, the capacitance of the capacitor 1 can be accurately set to a desired value by preventing the electrode from fading.

  Further, for example, as in the example shown in FIGS. 8A and 8B, the side on the side where the dummy electrode 6 does not exist in the lead portion 32 is preferably parallel to the side surface of the stacked body 6. Thereby, the internal electrode 3 can ensure a fixed space | interval from the side surface of a laminated body. Therefore, more reliable insulation can be ensured.

The dimensions of the first internal electrode 3b and the dielectric layer 5 shown in FIG. 8B are shown below.
When the width W of the dielectric layer 5 is 0.5 mm and the length L of the dielectric layer 5 is 1 mm, for example,
The width D of the dummy electrode 6 is 0.08 mm, the width E of the portion exposed from the stacked body of the first internal electrodes 3b is 0.26 mm, and the gap A between the first internal electrode 3b and the dummy electrode 6 is 0.08 mm. mm. When the width W of the dielectric layer 5 is 0.3 mm and the length L of the dielectric layer 5 is 0.6 mm, for example, the width D of the dummy electrode 6 is 0.07 mm, and the first internal electrode 3b The width E of the portion exposed from the laminate is 0.09 mm, and the gap A between the first internal electrode 3b and the dummy electrode 6 is 0.07 m.
m.

In the above description, the first internal electrodes 3a and 3b have been mainly described. Needless to say, the second internal electrode 3c may have the same configuration as the first internal electrodes 3a and 3b. .

Further, for example, as in the example shown in FIGS. 9A and 9B, the dummy electrodes 6 may be disposed on both sides of the first internal electrode 3a. In this case, the distance between the dummy electrodes 6 in the stacking direction is reduced on the end surface 2f and the side surfaces 2c and 2d of the stacked body 2. Therefore, when forming the first external electrode 4a by plating, it is possible to form the first external electrode 4a that is more difficult to break.

Further, in the above description, as shown in FIG. 3, the dummy electrode 6 exposed from the side surface 2c is disposed in a further skipped manner in the stacking direction between the dielectric layers provided with the first internal electrodes 3a and 3b. . The same applies to the dummy electrode 6 exposed from the side surface 2d. However, the present invention is not limited to this example, and the dummy electrode 6 may be disposed so as to be skipped by two or more layers in the stacking direction between the dielectric layers provided with the first internal electrodes 3a and 3b. Even in such a case, if the thickness of the dielectric layer 5 and the like is adjusted and the distance between the dummy electrodes 6 in the stacking direction is about 10 μm or less, the discontinuity of the first external electrode 4a between the dummy electrodes 6 is suppressed. it can. This is side 2
The same applies to the dummy electrode 6 exposed from d. Naturally, such an arrangement of the dummy electrodes 6 may be applied to the modified examples of FIGS.

1: Capacitor 2: Laminated body 3: Internal electrode 3a: One first internal electrode 3b: The other first internal electrode 3c: Second internal electrode 4: External electrode 4a: First external electrode 4b: Second external electrode 5 : Dielectric layer 6: Dummy electrode A: Gap

Claims (2)

A laminate in which a plurality of dielectric layers are laminated;
An internal electrode provided between the dielectric layers so as to face each other through the dielectric layer;
The internal electrodes are electrically connected, and external electrodes provided to cover the ends of the laminate;
At the end of the internal electrode, at least one of the two side surfaces of the laminate is disposed apart from the internal electrode and exposed from the side and end surfaces, and is electrically connected to the external electrode With a dummy electrode,
The gap between the internal electrode and the dummy electrode at the end face does not match between the dielectric layers provided with the internal electrodes adjacent in the stacking direction ,
The internal electrode has a capacitance forming portion facing each other through the dielectric layer, and a lead portion drawn from the capacitance forming portion to the end face,
The lead-out part is unevenly arranged on one side surface, and the dummy electrode is arranged on the other side surface. 2. The capacitor according to claim 1 , wherein in the internal electrode, the lead-out portion is led out to the end face so as to extend obliquely with respect to the side face.

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