JP5278476B2 - Multilayer capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stacked capacitor that reduces a product-specific variation in capacitance while suppressing penetration of a plating solution. <P>SOLUTION: In a stacked capacitor 100, an internal electrode layer 7 includes a first internal electrode 20 and a second internal electrode 30, and each internal electrode 20, 30 includes an active electrode portion 21, 31 of a fixed width positioned far from an end face and a lead electrode portion 22, 32 of a fixed width narrower than the active electrode portion 21, 31 and positioned near to the end face. An intermediate internal electrode layer 8 includes a third internal electrode 40, and the third internal electrode 40 has a shape extending in an X direction with overlaps on a part 22a of the lead electrode portion 22 of the first internal electrode 20 and a part 32a of the lead electrode portion 32 of the second internal electrode 30 and wider than the width w1 of the active electrode portion 21, 31 of each internal electrode 20, 30. <P>COPYRIGHT: (C)2013,JPO&amp;INPIT

Description

  The present invention relates to a multilayer capacitor.

  2. Description of the Related Art Conventionally, a multilayer capacitor formed by laminating a plurality of dielectric layers provided with an electrode pattern is known, and for example, disclosed in Patent Document 1 below. The multilayer capacitor disclosed in Patent Document 1 has an element body in which internal electrode layers and float electrode layers are alternately stacked via dielectric layers, and a series capacitor component is formed by the internal electrodes and the float electrodes. Is formed.

JP-A-7-135124

  When the multilayer capacitor as described above is manufactured, in the step of laminating the dielectric layers on which the electrode patterns are formed, a positional deviation (lamination misalignment) in a direction orthogonal to the laminating direction may occur between the dielectric layers that overlap one above the other. is there. Such a misalignment leads to variations in capacitance among the multilayer capacitor products. In particular, in a multilayer capacitor having a small capacitance (for example, about 10 pF) used in a recent high frequency filter of several gigahertz band, reduction of variation in the capacitance has become a very important technical problem.

  In addition, the terminal electrode is plated on the end face of the multilayer capacitor element, but if the plating solution used in the plating formation penetrates into the element body, the reliability of the multilayer capacitor is reduced. It is known to connect.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a multilayer capacitor in which variation in capacitance among products is reduced while suppressing infiltration of a plating solution. To do.

  A multilayer capacitor in accordance with the present invention is a multilayer capacitor including an element body in which internal electrode layers and intermediate internal electrode layers are alternately stacked via dielectric layers, the first end face of the element body facing each other, and The second end face is provided with a first terminal electrode and a second terminal electrode, respectively, and the internal electrode layer is electrically connected to the first terminal electrode and second from the first end face side. A first internal electrode extending in the end face direction, and a second internal electrode electrically connected to the second terminal electrode and extending from the second end face side in the first end face direction, The inner electrode and the second inner electrode are each of an active electrode portion having the same width located on the side farther from the end face, and the same width being narrower than the active electrode portion and closer to the end face than the active electrode portion And an intermediate internal electrode layer is formed on the first terminal electrode. And a third internal electrode that is not connected to any of the second terminal electrodes and forms a plurality of capacitance components connected in series between the first internal electrode and the second internal electrode, The internal electrode of the first internal electrode overlaps with a part of the extraction electrode part of the first internal electrode and a part of the extraction electrode part of the second internal electrode in a facing direction between the first end surface and the second end surface. It extends and has a shape wider than the width of the active electrode portion of the first internal electrode and the second internal electrode.

  In this multilayer capacitor, when a misalignment in the width direction of the third internal electrode occurs between the internal electrode layer and the intermediate internal electrode layer, the active electrode portions of the first internal electrode and the second internal electrode Since the third internal electrode has a shape wider than the width of the third internal electrode, it is possible to suppress a change in capacitance caused by stacking misalignment in the width direction of the third internal electrode. In addition, even when a stacking misalignment between the internal electrode layer and the intermediate internal electrode layer occurs in the extending direction of the third internal electrode (that is, the facing direction between the first end surface and the second end surface), Since the first internal electrode and the second internal electrode include the active electrode portion and the extraction electrode portion having the same width, it is possible to suppress a change in capacitance due to stacking misalignment in the extending direction of the third internal electrode. Can do. In particular, since the width of the extraction electrode portion is narrower than the width of the active electrode portion, the stacking deviation in the extending direction of the third internal electrode is smaller than when the narrow extraction electrode portion is not formed. In this case, the change in the facing area between the first internal electrode and the third internal electrode and the change in the facing area between the second internal electrode and the third internal electrode are reduced, and as a result, the first internal electrode The change in the combined capacitance of the plurality of capacitance components connected in series formed by the second internal electrode and the third internal electrode is reduced. As described above, since the multilayer capacitor according to the present invention can suppress the change in capacitance even when the multilayer deviation occurs, the variation in capacitance among products can be reduced.

  In addition, in the first internal electrode and the second internal electrode, since the width of each extraction electrode portion is narrower than the width of each active electrode portion, the first end face and the second end face of the element body have first When the terminal electrode and the second terminal electrode are formed by plating, it is difficult for the plating solution to enter, and a decrease in the reliability of the multilayer capacitor due to the penetration of the plating solution can be suppressed.

  The difference between the end position in the width direction of the active electrode portion of the first internal electrode and the second internal electrode and the end position in the width direction of the third internal electrode is the difference between the first internal electrode or the first internal electrode and the second internal electrode. The aspect larger than the difference of the edge part position of the extending direction of the active electrode part of 2 internal electrodes and the extending direction of the 3rd internal electrode may be sufficient. In this case, it is possible to effectively suppress the change in the capacitance due to the stacking misalignment in the width direction as compared with the stacking misalignment in the extending direction of the third internal electrode.

  Moreover, the aspect which an internal electrode layer located in the outermost direction in the lamination direction of an element body among several internal electrode layers may be located in the outer side in the lamination direction of an element body rather than an intermediate | middle internal electrode layer may be sufficient. When the intermediate internal electrode layer is located outside the internal electrode layer in the stacking direction of the element body, it is between the first terminal electrode and the second terminal electrode and the third internal electrode of the intermediate internal electrode layer. However, stray capacitance can be avoided by adopting the above embodiment.

  ADVANTAGE OF THE INVENTION According to this invention, the multilayer capacitor by which the dispersion | variation in the electrostatic capacitance between products was aimed at was suppressed, suppressing the penetration | invasion of plating solution.

FIG. 1 is a perspective view showing a multilayer capacitor according to an embodiment of the present invention. 2 is a cross-sectional view taken along the line II-II of the multilayer capacitor shown in FIG. 3 is a cross-sectional view taken along line III-III of the multilayer capacitor shown in FIG. FIG. 4 is a development view in which the element body of the multilayer capacitor of FIG. 1 is developed for each dielectric layer. FIG. 5 is a view of the first internal electrode and the second internal electrode of the internal electrode layer as seen from the stacking direction. FIG. 6 is a view of the third internal electrode of the intermediate internal electrode layer as viewed from the stacking direction. FIG. 7 is a view of the internal electrode layer of the multilayer capacitor according to the prior art as viewed from the lamination direction. FIG. 8 is a view of the outermost internal electrode layer as viewed from the stacking direction.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description, the same reference numerals are used for the same elements or elements having the same function, and redundant description is omitted.

  The configuration of the multilayer capacitor 100 according to the embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view showing the multilayer capacitor 100. FIG. 2 is a cross-sectional view taken along the line II-II of the multilayer capacitor 100 shown in FIG. 3 is a cross-sectional view of the multilayer capacitor 100 shown in FIG. 2 taken along the line III-III. FIG. 4 is a development view in which the element body 1 of the multilayer capacitor 100 is developed for each dielectric layer.

  As shown in FIG. 1, the multilayer capacitor 100 includes a base body 1 configured in a substantially rectangular parallelepiped shape by stacking and integrating a plurality of rectangular plate-shaped dielectric layers, a first terminal electrode 2, and a first terminal electrode 2. 2 terminal electrodes 3 are provided. The multilayer capacitor 100 has a length of about 0.4 to 5.7 mm, a width of 0.2 to 5.0 mm, and a thickness of about 0.2 to 3.2 mm.

  The first terminal electrode 2 is an external electrode formed on the first end face 1a in the longitudinal direction (X direction in the figure) of the element body 1 and covers the first end face 1a of the element body 1 and the end face Is formed so as to integrally cover a part of four side surfaces adjacent to each other. The second terminal electrode 3 is an external electrode formed on the opposite end surface (second end surface) 1b facing the first end surface 1a and covers the second end surface 1b of the element body 1. The four side surfaces adjacent to the end surface are integrally covered.

  The first terminal electrode 2 and the second terminal electrode 3 are plated on the element body 1. Specifically, a conductive paste mainly composed of Cu, Ni, Ag, Pd or the like is attached to the outer surface of the element body 1 by dipping or the like, and then baked at a predetermined temperature (for example, about 700 ° C.). It is formed by applying electroplating. Ni, Sn, etc. can be used for electroplating. The thicknesses of the first terminal electrode 2 and the second terminal electrode 3 are set to about 20 to 700 μm.

  As shown in FIGS. 2 and 3, the element body 1 is configured as a laminated body in which a plurality of rectangular plate-like dielectric layers 6, a plurality of internal electrode layers 7, and a plurality of intermediate internal electrode layers 8 are stacked. Has been. The internal electrode layer 7 and the intermediate internal electrode layer 8 are arranged one by one in the element body 1 along the stacking direction (Z direction in the figure) of the dielectric layer 6 (hereinafter simply referred to as “stacking direction”). Are disposed so as to sandwich at least one dielectric layer 6 therebetween. In the element body 1, the internal electrode layers 7 and the intermediate internal electrode layers 8 are alternately stacked via the dielectric layers 6. Of the plurality of internal electrode layers 7, the outermost internal electrode layer in the stacking direction is distinguished as the outermost internal electrode layer 9.

  Actually, the plurality of dielectric layers 6 in the element body 1 of the multilayer capacitor 100 are integrated to such an extent that the boundary between them cannot be visually recognized. As shown in FIG. 4, the element body 1 is formed by stacking and firing 10 ceramic green sheets and integrating them. Specifically, the ten ceramic green sheets are, in order from the top, the sheet 10 on which no electrode pattern is formed, the sheet 13 on which the electrode pattern of the outermost internal electrode layer 9 is formed, and the electrode of the intermediate internal electrode layer 8 Sheet 12 on which a pattern is formed, sheet 11 on which an electrode pattern of internal electrode layer 7 is formed, sheet 12 on which an electrode pattern of intermediate internal electrode layer 8 is formed, sheet 11 on which an electrode pattern of internal electrode layer 7 is formed The sheet 12 on which the electrode pattern of the intermediate internal electrode layer 8 is formed, the sheet 11 on which the electrode pattern of the internal electrode layer 7 is formed, the sheet 12 on which the electrode pattern of the intermediate internal electrode layer 8 is formed, the outermost internal electrode layer It is composed of a sheet 13 on which nine electrode patterns are formed.

Each sheet 10 to 13 _is configured such as BaTiO 3, CaZrO ₃ as the main component, its thickness, i.e. the thickness of the dielectric layer 6 after firing, there is a 6～60Myuemu. The electrode patterns of the sheets 11 to 13 include a conductive material such as Ni or Ni alloy, and are configured as a sintered body of a conductive paste including the conductive material.

  Next, the electrode pattern of the internal electrode layer 7 and the electrode pattern of the intermediate internal electrode layer 8 will be described with reference to FIGS.

  As shown in FIG. 5, the electrode pattern of the internal electrode layer 7 includes a pair of internal electrodes 20 and 30 (a first internal electrode 20 and a second internal electrode 30). Each of these internal electrodes 20 and 30 has a T shape, and is separated from the first end surface 1a and the second end surface 1b on the sheet 11 in a state of being separated by a predetermined length. They are arranged symmetrically with respect to a center line that intersects in a direction orthogonal to the figure (Y direction in the figure) (hereinafter referred to as “width direction”).

  The first internal electrode 20 is located on the first end face 1a side of the element body 1, is electrically connected to the first terminal electrode 2, and extends from the first end face 1a to the second end face 1b side. ing. The first internal electrode 20 includes an active electrode portion 21 located on the side far from the first end surface 1a, and an extraction electrode portion 22 located on the side closer to the first end surface 1a than the active electrode portion 21. Yes.

  The active electrode portion 21 has a rectangular shape, and the width in the width direction is a constant width w1. The extraction electrode part 22 also has a rectangular shape, and the width in the width direction is a constant width w2. The width w2 of the extraction electrode portion 22 is designed to be narrower than the width w1 of the active electrode portion 21 (that is, w2 <w1).

  The second internal electrode 30 is located on the second end face 1b side of the element body 1, is electrically connected to the second terminal electrode 3, and extends from the second end face 1b to the first end face 1a side. ing. The second internal electrode 30 is composed of an active electrode part 31 located on the side far from the second end face 1b and an extraction electrode part 32 located on the side closer to the second end face 1b than the active electrode part 31. Yes.

  The active electrode portion 31 has a rectangular shape similar to that of the active electrode portion 21 of the first internal electrode 20, and has a constant width w <b> 1 that is the same width as the active electrode portion 21. The extraction electrode portion 32 has a rectangular shape similar to that of the extraction electrode portion 22 of the first internal electrode 20, and has a constant width w <b> 2 that is the same width as the extraction electrode portion 22.

  As shown in FIG. 6, the electrode pattern of the intermediate internal electrode layer 8 is constituted by a third internal electrode 40 disposed in the center of the sheet 12. The third internal electrode 40 is not connected to the first terminal electrode 2 and the second terminal electrode 3, and both the electrodes 2 and 3 are electrically insulated. The third internal electrode 40 has a rectangular shape and extends in the facing direction between the first end surface 1a and the second end surface 1b. The third internal electrode 40 has a constant width w3, and this width w3 is wider than the width w1 of the active electrode portions 21 and 31 of the first internal electrode 20 and the second internal electrode 30 (that is, w3> w1) Designed.

  The length in the extending direction of the third internal electrode 40 covers the active electrode portion 21 of the first internal electrode 20 and the active electrode portion 31 of the second internal electrode 30, and further, the first internal electrode 20 The length is designed to be applied to a part 22 a of the lead electrode part 22 and a part 32 a of the lead electrode part 32 of the second internal electrode 30. Therefore, the third internal electrode 40 overlaps with the active electrode portion 21 of the first internal electrode 20 and the active electrode portion 31 of the second internal electrode 30, and the extraction electrode portion 22 of the first internal electrode 20. And a part 32 a of the extraction electrode part 32 of the second internal electrode 30.

  Thereby, the third internal electrode 40 forms two capacitance components connected in series between the first internal electrode 20 and the second internal electrode 30. Specifically, the third internal electrode 40 forms a capacitance component of the electrostatic capacitance C1 in the opposing region facing the first internal electrode 20, and electrostatically forms in the opposing region facing the second internal electrode 30. A capacitance component of the capacitance C2 is formed, and these capacitance components are connected in series to form a combined capacitance C (= C1 × C2 / (C1 + C2)).

  The position and size of the third internal electrode 40 are different from the positions and sizes of the first internal electrode 20 and the second internal electrode 30 in terms of the activity of the first internal electrode 20 and the second internal electrode 30. The difference d1 between the end position in the width direction of the electrode portions 21 and 31 and the end position in the width direction of the third internal electrode 40 is the active electrode of the first internal electrode 20 (or the second internal electrode 30). Designed to be larger than the difference d2 between the end position in the extending direction of the portion 21 (or the active electrode section 31) and the end position in the extending direction of the third internal electrode 40 (that is, d1> d2). .

  In the multilayer capacitor 100 having the above-described configuration, when a misalignment in the width direction (Y direction) occurs between the internal electrode layer 7 and the intermediate internal electrode layer 8, the first internal electrode 20 and the second internal electrode 20 Since the third internal electrode 40 has a wider shape (width w3) than the width w1 of the active electrode portions 21 and 31 of the internal electrode 30, stacking deviation is allowed by the difference d1 in the end position in the width direction. It is possible to suppress the change in capacitance due to the stacking deviation in the width direction of the third internal electrode 40.

  On the other hand, when the end positions in the width direction of the first internal electrode 20 ′, the second internal electrode 30 ′, and the third internal electrode 40 ′ are the same as in the prior art shown in FIG. However, the above-described stacking misalignment cannot be allowed, and as a result, the facing area is reduced due to the stacking misalignment, and the capacitance is greatly reduced.

  Even when a stacking shift in the extending direction (X direction) occurs between the internal electrode layer 7 and the intermediate internal electrode layer 8, the first internal electrode 20 and the second internal electrode 30 have the same width w1. Since the active electrode portions 21 and 31 and the extraction electrode portions 22 and 32 having the same width w2 are included, it is possible to suppress a change in capacitance due to the stacking deviation in the extending direction of the third internal electrode 40. In other words, even when a reduction in the area facing the third internal electrode 40 occurs in one of the first internal electrode 20 and the second internal electrode 30 due to the stacking deviation in the extending direction, the other internal In the electrode, the facing area increases (compensates) by the reduced area, so that the change in capacitance is effectively suppressed.

  In particular, since the width w2 of the extraction electrode portions 22 and 32 is narrower than the width w1 of the active electrode portions 21 and 31, the first internal electrode 20 and the third internal electrode 20 Changes in the facing area between the third internal electrode 40 and the facing area between the second internal electrode 30 and the third internal electrode 40 are reduced. That is, by changing the width w2 of the extraction electrode portions 22 and 32 to the width w1 of the active electrode portions 21 and 31 (w2 <w1), the change in the facing area due to stacking misalignment (for example, Δl misalignment). The amount (Δl × w2) is effectively reduced compared to the amount of change in the facing area (Δl × w1) when the width is not narrowed. Therefore, the amount of change in the capacitance C1 formed by the first internal electrode 20 and the third internal electrode 40 is reduced, and the second internal electrode 30 and the third internal electrode 40 are formed. As a result, the amount of change in the combined capacitance C is also reduced.

  As in the prior art shown in FIG. 7, the first internal electrode 20 ′ and the second internal electrode 30 ′ have a uniform width in the extending direction, and a narrow extraction electrode portion is not formed. In this case, the amount of change in the facing area becomes larger when the stacking misalignment in the extending direction of the third internal electrode 40 ′ is compared with the above-described aspect in which the extraction electrode portion is narrowed, and the combined capacitance C is thereby increased. It will change greatly.

  As described in detail above, in the multilayer capacitor 100, even if a multilayer deviation occurs, a change in capacitance can be suppressed, so that a variation in capacitance among products can be reduced. ing.

  Moreover, in the 1st internal electrode 20 and the 2nd internal electrode 30, by making the width w2 of each extraction electrode part 22 and 32 narrower than the width w1 of each active electrode part 21 and 31, element body 1 surface The separation from is planned. Therefore, when the first terminal electrode 2 and the second terminal electrode 3 are formed on the first end surface 1 a and the second end surface 1 b of the element body 1 by plating, the plating solution is less likely to enter the element body 1. In addition, the reliability of the multilayer capacitor 100 due to the penetration of the plating solution is suppressed.

  In addition, as shown in FIG. 6, regarding the positional relationship between the first internal electrode 20 (or the second internal electrode 30) and the third internal electrode 40, the difference d1 in the end position in the width direction is increased. Since it is larger than the difference d2 from the end position with respect to the current direction, it is possible to effectively suppress the change in capacitance caused by the stacking misalignment in the width direction compared to the stacking misalignment in the extending direction of the third internal electrode 40. be able to. As described above, in the stacking misalignment in the extending direction, the opposing area is mutually compensated between the first internal electrode 20 and the second internal electrode 30, but the stacking misalignment in the width direction is such an opposing area. Therefore, it is preferable to increase the allowable length (d1) with respect to the stacking deviation in the width direction.

  As shown in FIG. 8, the electrode pattern of the outermost internal electrode layer 9 is constituted by a pair of outermost internal electrodes 50 and 60 (fourth internal electrode 50 and fifth internal electrode 60). These internal electrodes 50 and 60 are arranged in line symmetry with respect to a center line traversing in the width direction on the sheet 13 while being separated by a predetermined length, and both have a rectangular shape. Both the fourth internal electrode 50 and the fifth internal electrode 60 have a constant width w4 in the width direction, and this width w4 is wider than the width w3 of the third internal electrode 40 (that is, w4). > W3) Designed.

  Like the first internal electrode 20, the fourth internal electrode 50 is located on the first end face 1a side of the element body 1, and is electrically connected to the first terminal electrode 2 and from the first end face 1a. It extends to the second end face 1b side. Like the second internal electrode 30, the fifth internal electrode 60 is located on the second end face 1b side of the element body 1 and is electrically connected to the second terminal electrode 3 and from the second end face 1b. It extends to the first end face 1a side.

  Here, the terminal electrodes 2 and 3 formed on the end faces 1 a and 1 b of the element body 1 of the multilayer capacitor 100 form a stray capacitance between the terminal electrodes 2 and 3 and the internal electrodes formed in the element body 1. In particular, stray capacitance tends to occur between the portion of the terminal electrodes 2 and 3 that wrap around the side surface of the element body 1 and the third internal electrode 40. Therefore, when the intermediate internal electrode layer 8 is located outside the internal electrode layer 7 in the stacking direction of the element body 1, the first terminal electrode 2, the second terminal electrode 3, and the intermediate internal electrode layer 8 A stray capacitance is generated between the third internal electrode 40 and the third internal electrode 40.

  Therefore, in the multilayer capacitor 100, the stray capacitance is suppressed by disposing the outermost internal electrode layer 9 in the uppermost layer and the lowermost layer of the element body 1. That is, since the internal electrodes 50 and 60 of the outermost internal electrode layer 9 are electrically connected to the terminal electrodes 2 and 3 having the same polarity, no stray capacitance is generated between the terminal electrodes 2 and 3. Further, the variation in capacitance among products is reduced. In particular, since the width w4 of the fourth internal electrode 50 and the fifth internal electrode 60 is designed to be wider than the width w3 of the third internal electrode 40, the terminal electrodes 2, 3 and the third internal electrode 40 are designed. The situation in which stray capacitance occurs between the two is effectively suppressed.

  DESCRIPTION OF SYMBOLS 100 ... Multilayer capacitor, 1 ... Element body, 1a ... 1st end surface, 1b ... 2nd end surface, 2 ... 1st terminal electrode, 3 ... 2nd terminal electrode, 6 ... Dielectric layer, 7 ... Internal electrode Layer 8 ... intermediate internal electrode layer 9 ... outermost internal electrode layer 20 ... first internal electrode 21,31 ... active electrode part 22,32 ... extraction electrode part 30 ... second internal electrode 40 ... 3rd internal electrode, 50 ... 4th internal electrode, 60 ... 5th internal electrode.

Claims (2)

A multilayer capacitor including an element body in which internal electrode layers and intermediate internal electrode layers are alternately stacked via dielectric layers,
A first terminal electrode and a second terminal electrode are respectively provided on the first end surface and the second end surface facing each other of the element body,
The internal electrode layer is electrically connected to the first terminal electrode and extends from the first end face side toward the second end face, and the second terminal electrode A second internal electrode that is electrically connected and extends in the first end face direction from the second end face side;
Each of the first internal electrode and the second internal electrode has an active electrode portion having the same width located on the side far from the end surface, and a side narrower than the active electrode portion and closer to the end surface than the active electrode portion And an extraction electrode portion of the same width located at
The intermediate internal electrode layer is not connected to any of the first terminal electrode and the second terminal electrode, and is connected in series between the first internal electrode and the second internal electrode. A third internal electrode forming a capacitive component of
The third internal electrode includes the first end face and the second end so as to overlap a part of the extraction electrode part of the first internal electrode and a part of the extraction electrode part of the second internal electrode. of extending in opposite direction of the end face, and have a wider shape than the width of the active electrode portion of the first internal electrode and the second internal electrode,
The difference between the end position in the width direction of the active electrode portion of the first internal electrode and the second internal electrode and the end position in the width direction of the third internal electrode is:
A stack that is larger than a difference between an end position in the extending direction of the active electrode portion of the first internal electrode or the second internal electrode and an end position in the extending direction of the third internal electrode. Capacitor. Among the plurality of the internal electrode layers, the internal electrode layer positioned on the outermost side in the stacking direction of the element body, located outside in the stacking direction of the intermediate said body than the internal electrode layers, to claim 1 The multilayer capacitor described.

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