JP2011100834A - Multilayer capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multilayer capacitor suppressing occurrence of failure such as cracks by a thermal shock. <P>SOLUTION: The multilayer capacitor 1 includes a capacitor element body 2 composed of a plurality of dielectric layers 10, internal electrodes 3, 4 disposed within the capacitor element body 2 and including main electrode sections 31, 41 and extraction electrode sections 32, 42, and terminal electrodes 5, 6 disposed on an outer surface of the capacitor element body 2 and provided with side face electrode sections 51, 61 and end face electrode sections 52, 62. Separation distance G between the terminal electrodes 5, 6 is shorter than electrode widths W2, W4 of the side face electrode sections 51, 61. The maximum thickness D2<SB>max</SB>of the end face electrode sections 52, 62 is smaller than the minimum thickness D1<SB>min</SB>of a part corresponding to the first and second extraction widths W1, W3 from among the side face electrode sections 51, 61. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a multilayer capacitor whose both end faces are substantially square.

  Conventionally, a rectangular parallelepiped element is formed by alternately laminating two types of internal electrodes respectively formed on different dielectric layers, and covers the end face of the element body and a part of the side surface adjacent to the end face. A multilayer capacitor in which a terminal electrode is provided is known (for example, see Patent Document 1). In such a multilayer capacitor, as its size is reduced, each end face is made substantially square, and any of the four side faces of the multilayer capacitor can be mounted on a circuit board as a mounting face.

JP 2004-296940 A

  By the way, in the multilayer capacitor described above, the thickness of the end face portion of the terminal electrode is thicker than the thickness of the side face portion. For this reason, when reflow soldering a multilayer capacitor to a substrate, the stress associated with the difference in thermal expansion between the terminal electrode formed of metal or the like and the element body formed of ceramic or the like is increased, and the thermal shock is applied to the multilayer capacitor. Failures such as cracks may occur.

  An object of this invention is to provide the multilayer capacitor which suppresses generation | occurrence | production of failures, such as a crack by a thermal shock.

  In order to solve the above-described problem, a multilayer capacitor according to the present invention includes first and second side surfaces that are connected to each other, and the first and second side surfaces of the substantially rectangular shape facing each other, and the first and second side surfaces. The third and fourth side surfaces extending in the long side direction and facing each other, and the first and second side surfaces extending in the short side direction so as to connect the first and second side surfaces and substantially facing each other A capacitor element body having a square first and second end faces and composed of a plurality of dielectric layers stacked in the opposing direction of the first and second side surfaces, and disposed in the capacitor element body And a first internal electrode having a first main electrode portion extending in a direction opposite to the first and second end faces and a first extraction electrode portion extending at a first extraction width toward the third and fourth side surfaces. The electrode is disposed in the capacitor body and is opposed to the first and second side surfaces. A second main electrode portion facing the first main electrode portion and extending in a facing direction of the first and second end faces and a second extraction electrode portion extending toward the third and fourth side surfaces. An internal electrode and a first electrode disposed on the outer surface of the capacitor body and located on the first end face side of the first, second, third and fourth side surfaces and connected to the first lead electrode portion A first terminal electrode having a side electrode part and a first end face electrode part located on the first end face; and disposed on an outer surface of the capacitor body; and first, second, third and fourth A second terminal electrode having a second side electrode part located on the second end face side of the side face and connected to the second extraction electrode part and a second end face electrode part located on the second end face; The distance between the first and second terminal electrodes is such that the electrode width of the first side electrode portion and the second side surface in the opposing direction of the first and second end faces. Shorter than the electrode width of the electrode portion, and the maximum thickness of the first end surface electrode portion, it is characterized in thinner than the minimum thickness of a portion corresponding to the first lead width of the first side surface electrode portions.

  In the multilayer capacitor according to the present invention, the maximum thickness of the first end face electrode portion is thinner than the minimum thickness of the portion corresponding to the first lead width in the first side face electrode portion. For this reason, the stress transmitted from the terminal electrode to the capacitor body due to a rapid temperature change such as a thermal shock applied to the multilayer capacitor is relieved, and the occurrence of a failure such as a crack due to the thermal shock can be suppressed. Further, since the thickness of the portion corresponding to the first extraction width in the first side surface electrode portion is thick, the plating solution enters from the exposed surface of the first extraction electrode portion into the first internal electrode. Can be effectively suppressed. On the other hand, since the thickness of the first end face electrode portion is reduced, the outer shape of the element body can be enlarged while keeping the outer shape of the multilayer capacitor the same size, thereby increasing the areas of the first and second internal electrodes. Thus, the capacitance of the multilayer capacitor can be increased.

  In the multilayer capacitor according to the present invention, the lead electrode portions of the first and second internal electrodes are drawn in the third and fourth side surfaces of the capacitor body and connected to the first and second terminal electrodes. ing. For this reason, even when any one of the side surfaces is mounted as a mounting surface, variation in the equivalent series inductance (hereinafter referred to as “ESL”) of the multilayer capacitor can be reduced. In the multilayer capacitor according to the present invention, the distance between the first and second terminal electrodes is such that the electrode width of the first side electrode part and the electrode of the second side electrode part in the opposing direction of the first and second end faces. It is shorter than the width. In this case, the first extraction width of the first extraction electrode portion connected to the first side electrode portion and the extraction width of the second extraction electrode portion connected to the second side electrode portion can be increased. In addition, it is possible to increase currents flowing in different directions in the second extraction electrode portion. As a result, magnetic fields generated by the respective currents are canceled out, and ESL in the multilayer capacitor can be reduced.

  Preferably, the second extraction electrode portion extends with a second extraction width toward the third and fourth side surfaces, and the maximum thickness of the second end surface electrode portion is the second extraction width of the second side electrode portions. It is thinner than the minimum thickness of the part corresponding to. In this case, the occurrence of a failure such as a crack due to thermal shock can be further suppressed, and the penetration of the plating solution from the exposed surface of the second extraction electrode portion into the second internal electrode can be suppressed. On the other hand, since the thickness of the second end face electrode portion is thin, the areas of the first and second internal electrodes can be further increased while keeping the outer shape of the capacitor the same, and the capacitance of the multilayer capacitor can be further increased. It becomes possible to do.

  ADVANTAGE OF THE INVENTION According to this invention, the multilayer capacitor which suppresses generation | occurrence | production of failures, such as a crack by a thermal shock, can be provided.

It is a perspective view of a multilayer capacitor. It is a disassembled perspective view of a multilayer capacitor. It is the III-III sectional view taken on the line in FIG. It is a partial expanded sectional view of the side part of a multilayer capacitor. It is a partially expanded sectional view of the edge part of a multilayer capacitor. (A) is a figure which shows the capacitor | condenser body when a multilayer capacitor is mounted in a horizontal direction, (b) is a figure which shows a capacitor | condenser body when a multilayer capacitor is mounted in a vertical 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.

  First, the configuration of the multilayer capacitor 1 will be described with reference to FIGS. The multilayer capacitor 1 includes a rectangular parallelepiped capacitor element body 2, internal electrodes 3 and 4 disposed in the capacitor element body 2, and terminal electrodes 5 and 6 disposed on the outer surface of the capacitor element body 2. Multilayer capacitor.

  The capacitor element body 2 is composed of a plurality of laminated dielectric layers 10, rectangular first and second side surfaces 2 a and 2 b facing each other in the same direction as the lamination direction, and first and second side surfaces. The rectangular third and fourth side surfaces 2c and 2d extending in the long side direction of 2a and 2b and facing each other, and the substantially square shape extending in the short side direction of the first and second side surfaces 2a and 2b and facing each other. 1st and 2nd end surface 2e, 2f are included. The third and fourth side surfaces 2c and 2d and the first and second end surfaces 2e and 2f extend so as to connect the first and second side surfaces 2a and 2b.

  The first and second end faces 2e and 2f have a substantially square shape as described above. The “substantially square” used here means that the multilayer capacitor 1 is attached to the circuit board (see FIG. 6). Regardless of which side surface 2a to 2d is mounted as a mounting surface, the length in one side in the height direction and the side in the width direction are within a predetermined intersection range so that the same mounting structure can be considered in design. Means a square. For example, when the size of the target product is “1005 (multilayer capacitor having a length of 1.0 mm, a height of 0.5 mm, and a width of 0.5 mm)”, each length on the end face of the size “1005” is a reference of 0.5 mm. The maximum deviation of each length is 22.2%, but shapes having such a difference are also included in the “substantially square”.

  As shown in FIGS. 2 and 3, the capacitor body 2 includes a first internal electrode 3 formed on the dielectric layer 10 and a second internal electrode formed on another dielectric layer 10. The internal electrodes 4 are arranged. A plurality of first internal electrodes 3 and second internal electrodes 4 are alternately stacked with dielectric layers 10 interposed therebetween. The dielectric layer 10 is made of, for example, a sintered body of a ceramic green sheet containing barium titanate as a main component and including a dielectric ceramic. Each of the internal electrodes 3 and 4 is made of, for example, a sintered body of a conductive paste obtained by mixing a binder resin or the like with a metal powder such as Ni, Ag, or Pd. The actual multilayer capacitor 1 is integrated so that the boundary between the dielectric layers 10 is not visible.

  The first internal electrode 3 is a substantially rectangular internal electrode, and has a rectangular first main electrode portion 31 disposed in the central portion on the dielectric layer 10 and a first end face 2 e of the first main electrode portion 31. And a first extraction electrode portion 32 formed to be connected to the side portion on the side and extending toward the third and fourth side surfaces 2c and 2d. The first main electrode portion 31 is formed such that each side portion thereof is separated from the third and fourth side surfaces 2c and 2d and extends in a direction opposite to the first and second end surfaces 2e and 2f. Yes. The first extraction electrode part 32 drawn out to the third and fourth side faces 2c, 2d has a width W2 wider than the first extraction width W1 of the first extraction electrode part 32 on the side faces 2c, 2d. One terminal electrode 5 is electrically and physically connected.

  The second internal electrode 4 is a substantially rectangular internal electrode, and has a rectangular second main electrode portion 41 disposed in the central portion on another dielectric layer 10, and a second main electrode portion 41 of the second main electrode portion 41. A second extraction electrode portion 42 is formed to be connected to the side portion on the end surface 2f side and extend toward the third and fourth side surfaces 2c and 2d. The second main electrode portion 41 is formed such that each side portion thereof is spaced apart from the third and fourth side surfaces 2c and 2d and extends in the opposing direction of the first and second end surfaces 2e and 2f. Yes. The second extraction electrode portion 42 extracted to the third and fourth side surfaces 2c, 2d has a width W4 wider than the second extraction width W3 of the second extraction electrode portion 42 on each of the side surfaces 2c, 2d. The two terminal electrodes 6 are electrically and physically connected.

  The first and second internal electrodes 3 and 4 are alternately stacked via any one of the plurality of dielectric layers 10 in the opposing direction of the first and second side surfaces 2a and 2b. Is done. By this lamination, the first and second main electrode portions 31 and 41 are opposed to each other over substantially the entire surface in the opposing direction of the first and second side surfaces 2a and 2b, and the capacitance portion of the multilayer capacitor 1 is configured. . In this embodiment, as will be described later, the internal electrodes 3 and 4 are formed so as to be larger than the conventional multilayer capacitor having the same outer size. It is larger than that. In addition, since each of the first extraction electrode portion 32 and the second extraction electrode portion 42 is configured to extend toward the third and fourth side surfaces 2c and 2d, any one of the side surfaces 2a to 2d is used as a mounting surface. Even when the multilayer capacitor 1 is mounted, the ESL variation of the multilayer capacitor 1 can be reduced, and the current flowing through each of the extraction electrode portions 32 and 42 is reversed to cancel the magnetic field. It is a structure that can reduce.

  The first terminal electrode 5 is disposed on the outer surface of the capacitor body 2 so as to cover the first end surface 2e side portion of the first to fourth side surfaces 2a to 2d and the substantially entire surface of the first end surface 2e. The The part located in the 1st end surface 2e side of the 1st-4th side surfaces 2a-2d comprises the 1st side surface electrode part 51, and the part located in the 1st end surface 2e comprises the 1st end surface electrode part 52. To do. The width of the first side surface electrode portion 51 in the facing direction of the first and second end surfaces 2e and 2f is the electrode width W2, and the third side surface 2c and 2d have the width of the first inner electrode 3 One lead electrode part 32 is connected.

  The second terminal electrode 6 covers a portion on the second end face 2f side of the first to fourth side faces 2a to 2d and a substantially entire face of the second end face 2f so as to face the first terminal electrode 5. In this way, the capacitor body 2 is disposed on the outer surface. A portion located on the second end face 2f side of the first to fourth side faces 2a to 2d constitutes the second side face electrode part 61, and a part located on the second end face 2f constitutes the second end face electrode part 62. To do. The width of the second side surface electrode portion 61 in the opposing direction of the first and second end surfaces 2e and 2f is the electrode width W4. Connected to the two extraction electrode portions 42.

  The first and second terminal electrodes 5 and 6 have a substantially U-shaped cross-sectional shape, and face each other inward in a separated state so as not to be connected to each other. The distance between the inner tip of the terminal electrode 5 and the inner tip of the second terminal electrode 6 is a separation distance G. The separation distance G is shorter than the electrode widths W2 and W4 of the terminal electrodes 5 and 6, and the ESL value of the multilayer capacitor 1 is reduced as described above. The terminal electrodes 5 and 6 are formed, for example, by applying a conductive paste containing conductive metal powder mainly composed of Ag, Cu, or Ni, glass frit, or the like to the outer surface of the capacitor body 2 and baking it. . If necessary, a plating layer may be formed on the baked electrode.

  Next, the relationship between the thicknesses of the cross-sectional shapes of the terminal electrodes 5 and 6 will be described in more detail with reference to FIGS.

The first side electrode portion 51 of the first terminal electrode 5 is formed so that its thickness D1 gradually increases from the central portion of the multilayer capacitor 1 toward the outside. As shown in FIG. 4, the first side electrode portion 51 has a thickness corresponding to the first lead width W1 of the first lead electrode portion 32 at one end on the center portion side of the multilayer capacitor. minimum value D1 _min next, outwardly gradually thickened D1, and is configured so that the thickness of the outside of the other end is the maximum value D1 _max at the corresponding portion.

On the other hand, the first end face electrode portion 52 of the first terminal electrode 5 is formed to be thinner than the terminal electrode of the conventional multilayer capacitor, and is shown in FIG. 5 within the range of the thin thickness. As described above, the second end face 2e is gradually increased from the outer portion (third or fourth side face 2c, 2d) of the multilayer capacitor 1 toward the center side along the first end face 2e. It protrudes from the outside toward the outside. In the first end electrode portion 52 formed as described above, in the substantially central portion, the thickness D2 is the maximum value D2 _max. And in the 1st terminal electrode 5 which has the 1st side surface electrode part 51 which is minimum thickness _D1min etc., and the 1st end surface electrode part 52 which is maximum thickness _D2max etc., maximum thickness D2 of the 1st end surface electrode part 52 is shown. _The relationship that _max is thinner than the minimum thickness D1 _{min of the} part corresponding to the 1st extraction width W1 among the 1st side surface electrode parts 51 is formed.

The second terminal electrode 6 also has a shape that is line symmetric with the first terminal electrode 5 described above, and the second side electrode portion 61 gradually increases in thickness from the central portion of the multilayer capacitor 1 toward the outside. It is formed so that D2 increases. Further, although not shown, the second side electrode portion 61 is not shown in the figure, and in the portion corresponding to the second lead width W3 of the second lead electrode portion 42, as in the first side electrode portion 51, the central portion side of the multilayer capacitor. The thickness at one end is the minimum value D1 _min at the corresponding portion, the thickness D1 is gradually increased toward the outside, and the thickness at the other end is the maximum value D1 _max at the corresponding portion. Has been.

On the other hand, the second end face electrode portion 62 of the second terminal electrode 6 is formed so as to be thinner than the conventional terminal electrode, and the first end face is omitted in the range of the thin thickness, although not shown. Similarly to the electrode portion 52, the multilayer capacitor 1 is formed to project outward from the second end surface 2f so that its thickness D2 gradually increases from the outer portion along the second end surface 2f toward the center. ing. In the second end electrode portion 62 formed as described above, in the substantially central portion, the thickness D2 is the maximum value D2 _max. Even in the second terminal electrode 6 having the second side surface electrode portion 61 having the minimum thickness D1 _{min and the} like and the second end surface electrode portion 62 having the maximum thickness D2 _{max and the} like, the maximum thickness D2 of the second end surface electrode portion 62 is obtained. _The relationship that _max is thinner than the minimum thickness D1 _{min of the} part corresponding to the 2nd extraction width W3 among the 2nd side surface electrode parts 61 is formed. In addition, since the terminal electrodes 5 and 6 having such a thickness can be formed using a conventional technique, the description thereof is omitted.

As described above, in the multilayer capacitor 1 according to this embodiment, the maximum thickness D2 _{max of} the first end face electrode portion 52 is the minimum thickness D1 of the portion corresponding to the first lead width W1 in the first side face electrode portion 51. _It is thinner than _min . The maximum thickness _{D2 max} of the second end electrode portion 62 is thinner than the minimum thickness _{D1 min} of a portion corresponding to the second lead width W3 of the second side surface electrode portions 61. For this reason, the stress transmitted from the terminal electrodes 5 and 6 to the capacitor body 2 due to a rapid temperature change such as a thermal shock applied to the multilayer capacitor 1 is relieved, and the occurrence of a failure such as a crack due to the thermal shock can be suppressed. it can.

  Moreover, since the thickness of the part corresponding to 1st and 2nd extraction width W1, W3 among the 1st and 2nd side surface electrode parts 51 and 61 is thick, respectively, the 1st and 2nd extraction electrode part 32 is shown. , 42 can effectively suppress the penetration of the plating solution into the first and second internal electrodes 3, 4. On the other hand, since the thicknesses of the first and second end face electrode portions 52 and 62 are reduced, the length of the capacitor body 2 with the outer shape of the multilayer capacitor 1 being the same size (see the full length L2 in FIG. 3). L1 can be increased, whereby the areas of the first and second internal electrodes 3 and 4 can be increased, and the capacitance of the multilayer capacitor 1 can be increased.

  In the multilayer capacitor 1 according to this embodiment, since the first and second end faces 2e and 2f are substantially square, as shown in FIG. 6, any one of the side faces 2a to 2d is defined as a mounting face. Even in this case, the same mounting shape can be obtained. In addition, the lead electrode portions 32 and 42 of the first and second inner electrodes 3 and 4 are drawn in the direction of the third and fourth side surfaces 2c and 2d of the capacitor element body 2, and the first and second terminals. Since it is connected to the electrodes 5 and 6, even when any one of the side surfaces 2a to 2d is mounted as a mounting surface, variations in ESL of the multilayer capacitor 1 can be reduced. As a result, if the multilayer capacitor 1 is used, the multilayer capacitor 1 can be mounted on the substrate S without worrying about the mounting direction, thereby improving the efficiency of the mounting operation.

  In the multilayer capacitor 1 according to this embodiment, the separation distance G between the first and second terminal electrodes 5 and 6 is such that the first side surface electrode portion 51 has a separation distance G in the facing direction of the first and second end surfaces 2e and 2f. The electrode width W2 and the electrode width W4 of the second side surface electrode portion 61 are shorter. In this case, the first extraction width W1 of the first extraction electrode portion 32 connected to the first side surface electrode portion 51 and the second extraction width W3 of the second extraction electrode portion 42 connected to the second side surface electrode portion 61. The current flowing in different directions in the first and second extraction electrode portions 32 and 42 can be increased, and as a result, the magnetic field generated by each current is canceled, and the ESL in the multilayer capacitor 1 is reduced. It becomes possible.

  The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the above-described embodiments, and various modifications are possible. For example, the first and second inner electrodes 3 and 4 described above are not configured to be exposed to the first and second end faces 2e and 2f and connected to the terminal electrodes 5 and 6 in this embodiment. However, the first and second inner electrodes 3 and 4 further have an extraction electrode portion that is extracted toward the first and second end faces 2e and 2f, and these extraction electrode portions are the first and second terminal electrodes. 5 and 6 may be connected.

  DESCRIPTION OF SYMBOLS 1 ... Multilayer capacitor, 2 ... Capacitor body, 3 ... 1st internal electrode, 4 ... 2nd internal electrode, 5 ... 1st terminal electrode, 6 ... 2nd terminal electrode, 10 ... Dielectric layer, 31 ... 1st main electrode part, 32 ... 1st extraction electrode part, 41 ... 2nd main electrode part, 42 ... 2nd extraction electrode part, 51 ... 1st side electrode part, 52 ... 1st end surface electrode part, 61 ... 1st 2 side electrode parts, 62 ... 2nd end surface electrode part.

Claims (2)

First and second substantially rectangular side surfaces facing each other, and third and third surfaces extending in the long side direction of the first and second side surfaces so as to connect the first and second side surfaces and facing each other. A fourth side surface and substantially square first and second end surfaces extending in the short side direction of the first and second side surfaces and facing each other so as to connect the first and second side surfaces. And a capacitor body composed of a plurality of dielectric layers stacked in the opposing direction of the first and second side surfaces,
A first main electrode portion disposed in the capacitor body and extending in a direction opposite to the first and second end faces and a first lead extending toward the third and fourth side faces with a first lead width. A first internal electrode having an electrode portion;
A second main electrode portion disposed in the capacitor body and facing the first main electrode portion in the facing direction of the first and second side surfaces and extending in the facing direction of the first and second end surfaces And a second internal electrode having a second extraction electrode portion extending toward the third and fourth side surfaces,
A first electrode disposed on the outer surface of the capacitor body and located on the first end face side of the first, second, third and fourth side surfaces and connected to the first lead electrode portion. A first terminal electrode having a side electrode part and a first end face electrode part located on the first end face;
A second electrode disposed on the outer surface of the capacitor body and located on the second end face side of the first, second, third and fourth side surfaces and connected to the second lead electrode portion. A second terminal electrode having a side electrode part and a second end face electrode part located on the second end face;
A separation distance between the first and second terminal electrodes is shorter than an electrode width of the first side electrode part and an electrode width of the second side electrode part in a facing direction of the first and second end faces; and ,
The multilayer capacitor, wherein a maximum thickness of the first end face electrode portion is thinner than a minimum thickness of a portion corresponding to the first lead width in the first side face electrode portion. The second extraction electrode portion extends with a second extraction width toward the third and fourth side surfaces,
2. The multilayer capacitor according to claim 1, wherein a maximum thickness of the second end surface electrode portion is thinner than a minimum thickness of a portion of the second side surface electrode portion corresponding to the second lead width.

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