JP2017028229A - Laminated capacitor and implementation structure therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated capacitor capable of suppressing the propagation of vibration to a substrate.SOLUTION: A laminated capacitor 10 includes a laminate 1 and a pair of external electrodes 3 connected to an internal electrode layer 2. The laminate 1 has a rectangular upper surface 4a and lower surface 4b, a pair of side surfaces 4e, 4f adjacent to the long sides of the upper surface 4a and lower surface 4b, and a pair of end surfaces 4c, 4d adjacent to the short sides of the upper surface 4a and lower surface 4b. The pair of external electrodes 3 include side surface portions 3a1, 3b1 disposed on the side surfaces 4e, 4f, upper surface extension portions 3a2, 3b2 extending on the upper surface 4a, and lower surface extension portions 3a3, 3b3 extending on the lower surface 4b. The thickness of the lower surface extension portions 3a3, 3b3 is thicker than the thickness of the upper surface extension portions 3a2, 3b2.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a multilayer capacitor in which a pair of external electrodes is provided on a multilayer body in which a plurality of dielectric layers and internal electrode layers are alternately stacked.

  In multilayer capacitors, dielectric layers and internal electrode layers are alternately stacked, and a ferroelectric material such as barium titanate with a relatively high dielectric constant is generally used as the ceramic material for the dielectric layer. It is used for. For example, when a DC voltage on which an AC component is superimposed is applied to such a multilayer capacitor, the dielectric layer is distorted due to the electrostrictive effect of the voltage, and the multilayer capacitor itself vibrates. The multilayer capacitor is mounted on the substrate via solder or the like, and the vibration of the multilayer capacitor itself propagates to the substrate, and the vibration is amplified by the resonance of the substrate due to the vibration propagated to the substrate. Will occur. When the substrate resonates at an audible resonance frequency, an audible sound is generated from the substrate, and a so-called “sounding” phenomenon occurs. Specifically, in a multilayer capacitor, a pair of external electrodes and a substrate are mounted via solder, and the vibration of the multilayer capacitor deforms the substrate via a solder joint formed on the external electrode. A vibration sound is generated in the substrate.

  The multilayer capacitor is provided with a pair of external electrodes at the center of a pair of side surfaces in the short direction of the multilayer body in order to reduce noise. An example of such a multilayer capacitor is disclosed in Patent Document 1.

JP 2007-194312 A

  However, the above-described multilayer capacitor structure has a problem in that the thickness of the external electrode of the multilayer capacitor is not taken into consideration, and a sufficient vibration suppressing effect cannot be obtained.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a multilayer capacitor and a mounting structure that can further reduce noise.

  The multilayer capacitor according to one aspect of the present invention includes a rectangular parallelepiped laminate in which dielectric layers and internal electrode layers are alternately laminated, and the different internal electrode layers provided on the outer surface of the laminate. A pair of external electrodes electrically connected to each other, and the stacked body is positioned in the stacking direction of the dielectric layer and the internal electrode layer, and has a rectangular upper surface and a lower surface facing each other. And a pair of side surfaces adjacent to the long side of the upper surface and the lower surface, and a pair of end surfaces adjacent to the short side of the upper surface and the lower surface, and the pair of external electrodes includes a central portion of the side surface. A side surface portion provided on the side surface, an upper surface extending portion extending from the side surface portion to the upper surface, and a lower surface extending portion extending from the side surface portion to the lower surface, and the external electrode The thickness of the lower surface extending portion is greater than the thickness of the upper surface extending portion. Thicker Some characterized.

Also, the multilayer capacitor according to one aspect of the present invention includes a rectangular parallelepiped laminate in which dielectric layers and internal electrode layers are alternately laminated, and the different internal parts provided on the outer surface of the laminate. A pair of external electrodes electrically connected to the electrode layers, respectively, and the stacked body is positioned in the stacking direction of the dielectric layer and the internal electrode layer and has a rectangular upper surface facing each other and A bottom surface; a pair of side surfaces adjacent to the long side of the top surface and the bottom surface; and a pair of end surfaces adjacent to the short side of the top surface and the bottom surface, and the external electrode includes a central portion of the end surface. The end surface portion provided on the end surface, an upper surface extending portion extending from the end surface portion to the upper surface, and a lower surface extending portion extending from the end surface portion to the lower surface, and the external electrode The thickness of the lower surface extending portion is greater than the thickness of the upper surface extending portion. Thicker and is characterized in.

  In the multilayer capacitor mounting structure according to one aspect of the present invention, the multilayer capacitor and the substrate are disposed so that the lower surface and the mounting surface of the substrate face each other, and the pair of the capacitors It is characterized by being joined via an external electrode.

  According to the multilayer capacitor of the present invention, the pair of external electrodes has an upper surface extending portion extending to the upper surface of the multilayer body and a lower surface extending portion extending to the lower surface. Since the thickness is thicker than the thickness of the upper surface extending portion, it is possible to further reduce noise.

(A) is a schematic perspective view which shows the multilayer capacitor | condenser which concerns on Embodiment 1, (b) is the cut part end view cut | disconnected by the AA line of the multilayer capacitor | condenser shown to (a), (c) is sectional drawing cut | disconnected by the BB line of the multilayer capacitor | condenser shown to (a). 1A is a plan view of the multilayer capacitor shown in FIG. 1 viewed from the top side, FIG. 1B is a side view of the multilayer capacitor shown in FIG. 1 viewed from the side, and FIG. It is the top view which looked at the multilayer capacitor from the lower surface side. (A)-(c) is a top view for demonstrating an internal electrode layer. FIG. 5 is a cross-sectional view of the multilayer capacitor according to Embodiment 2 cut along a line corresponding to line BB. 4A is a plan view of the multilayer capacitor shown in FIG. 4 as viewed from the upper surface side, FIG. 4B is a side view of the multilayer capacitor shown in FIG. 4 as viewed from the side surface, and FIG. It is the top view which looked at the multilayer capacitor from the lower surface side. FIG. 10 is a cross-sectional view taken along a line corresponding to the BB line, which is another example of the multilayer capacitor in accordance with Embodiment 2. (A) is a schematic perspective view which shows the multilayer capacitor | condenser which concerns on Embodiment 3, (b) is the cutting part end view cut | disconnected by the AA line of the multilayer capacitor | condenser shown to (a), (c) is sectional drawing cut | disconnected by the BB line of the multilayer capacitor | condenser shown to (a). (A) And (b) is sectional drawing which is another example of the multilayer capacitor | condenser which concerns on Embodiment 3, and cut | disconnected by the line corresponded to the BB line. (A) is a schematic perspective view which shows the multilayer capacitor | condenser which concerns on Embodiment 4, (b) is sectional drawing cut | disconnected by CC line of the multilayer capacitor | condenser shown to (a), (c) FIG. 3 is an end view of a cut portion taken along line DD of the multilayer capacitor shown in FIG. (A) is a schematic perspective view showing a state in which the multilayer capacitor shown in FIG. 1 is mounted on a substrate, and (b) is a diagram in which the multilayer capacitor shown in (a) is cut along line EE. It is sectional drawing which shows the mounting structure mounted in the board | substrate. (A) is a schematic perspective view showing a conventional multilayer capacitor, (b) is a plan view seen from the Z direction of a coordinate axis, and (c) is a substrate mounting of the multilayer capacitor of (b) on a substrate. It is sectional drawing which shows the conventional mounting structure cut | disconnected by the FF line | wire. It is a graph which shows the impedance measurement result at the time of applying 4V DC bias to the conventional multilayer capacitor single-piece | unit. It is the model of the model of the finite element method used for the calculation of the vibration mode of the conventional multilayer capacitor single-piece | unit. (A) is the perspective view seen from the symmetrical plane side which shows the calculation result of the vibration at 10 kHz of the conventional multilayer capacitor single body, (b) is the surface side which shows the calculation result of the vibration at 10 kHz of the conventional multilayer capacitor single body It is the perspective view seen from. (A) is a perspective view schematically showing a vibration mode node in a conventional multilayer capacitor alone, and (b) schematically shows a state in which an external electrode is provided on the vibration mode node in (a). FIG. FIG. 2 is an explanatory diagram for explaining a manufacturing method of the multilayer capacitor shown in FIG. 1.

<Embodiment 1>
Hereinafter, the multilayer capacitor 10 according to the first embodiment of the present invention will be described with reference to the drawings. In addition, for convenience, the multilayer capacitor 10 defines an orthogonal coordinate system XYZ, and uses the terms “upper surface” or “lower surface” with the positive side in the Z direction as the upper side. In the present embodiment, one of the pair of main surfaces is the upper surface 4a, and the other is the lower surface 4b. In addition, in each drawing, the same code | symbol is used about the same member and the same part, and the overlapping description is abbreviate | omitted.

  FIG. 1A is a schematic perspective view showing a multilayer capacitor 10 according to Embodiment 1 of the present invention. The multilayer capacitor 10 includes a dielectric layer 1a and an internal electrode layer 2 (first internal electrode). The rectangular parallelepiped laminated body 1 in which the layers 2a and the second internal electrode layers 2b) are alternately laminated, and the internal electrode layers 2 provided on the pair of side surfaces 4e and 4f in the short direction of the laminated body 1 and different from each other. And a pair of external electrodes 3 (a first external electrode 3a and a second external electrode 3b) that are electrically connected to each other. The laminated body 1 has a rectangular parallelepiped shape in which first internal electrode layers 2a and second internal electrode layers 2b are alternately laminated via dielectric layers 1a.

  The multilayer body 1 includes a rectangular upper surface 4a and a lower surface 4b that are positioned in the stacking direction of the dielectric layer 1a and the internal electrode layer 2 (the first internal electrode layer 2a and the second internal electrode layer 2b) and face each other. A pair of side surfaces (a first side surface 4e and a second side surface 4f) facing each other and positioned between the upper surface 4a and the lower surface 4b and adjacent to the long sides of the upper surface 4a and the lower surface 4b, and an upper surface 4a A pair of end faces (first end face 4c and second end face 4d) facing each other and located between the lower face 4b and adjacent to the short sides of the upper face 4a and the lower face 4b are provided. The pair of side surfaces (first side surface 4e and second side surface 4f) are positioned in the longitudinal direction (X direction) of the laminate 1, and the pair of end surfaces (first end surface 4c and second end surface 4d). It is located in the lateral direction (Y direction) of the laminate 1.

  As described above, the laminate 1 has a pair of end surfaces (the first end surface 4c and the second end surface 4d) positioned between the upper surface 4a and the lower surface 4b and orthogonal to the upper surface 4a and the lower surface 4b. Side surfaces (the first side surface 4e and the second side surface 4f) are located between the upper surface 4a and the lower surface 4b and orthogonal to the upper surface 4a and the lower surface 4b, and a pair of end surfaces (the first end surface 4c and the first side surface 4f). 2 end face 4d) and a pair of side faces (first side face 4e and second side face 4f) are orthogonal to each other. The rectangular parallelepiped shape includes not only a cubic shape or a rectangular parallelepiped shape, but also includes, for example, a shape in which a ridge line portion of the rectangular parallelepiped is chamfered and the ridge line portion has an R shape.

  The laminated body 1 is a sintered body obtained by laminating and firing a plurality of ceramic green sheets in which the internal electrode layer 2 is formed on the surface of the dielectric layer 1a. Thus, the multilayer body 1 is formed in a rectangular parallelepiped shape, and a plane that is a cross section (XY plane) in a direction orthogonal to the stacking direction (Z direction) of the dielectric layer 1a and the internal electrode layer 2 is rectangular. It has become.

As shown in FIG. 1, the pair of external electrodes 3 includes a first external electrode 3a and a second external electrode 3b. The first external electrode 3a has a side surface portion 3a1, an upper surface extension portion 3a2, and a lower surface extension portion 3a3, and the first side surface so that the side surface portion 3a1 includes the central portion of the first side surface 4e. 4e, the upper surface extending portion 3a2 extends from the side surface portion 3a1 toward the central portion in the short direction (Y direction) of the multilayer body 1 on the upper surface 4a, and the lower surface extending portion 3a3 extends from the side surface portion 3a1. The layered body 1 extends on the lower surface 4b toward the center in the short direction (Y direction).

  The second external electrode 3b has a side surface portion 3b1, an upper surface extension portion 3b2, and a lower surface extension portion 3b3, and the second side electrode 3b1 includes the central portion of the second side surface 4f. The upper surface extending portion 3b2 extends on the upper surface 4a from the side surface portion 3b1 toward the central portion in the short direction (Y direction) of the stacked body 1, and the lower surface extending portion 3b3 is the side surface portion. It extends on the lower surface 4b from 3b1 toward the center in the short direction (Y direction) of the laminate 1.

  FIG. 2 is a top view, a side view, and a bottom view of the multilayer capacitor 10, and shows the shape of the pair of external electrodes 3, respectively. FIG. 2A is a plan view of the multilayer capacitor 10 viewed from the upper surface 4a side, and shows an upper surface extension portion 3a2 of the first external electrode 3a and an upper surface extension portion 3b2 of the second external electrode 3b. FIG. 2B is a side view of the multilayer capacitor 10 viewed from the side of the first side surface 4e (second side surface 4f), and the side surface portion 3a1 (second side) of the first external electrode 3a. 2C shows a side surface portion 3b1) of the external electrode 3b. FIG. 2C is a plan view of the multilayer capacitor 10 viewed from the lower surface 4b side, and the lower surface extension portion 3a3 and the first outer electrode 3a. The lower surface extending portions 3b3 of the two external electrodes 3b are shown.

  As shown in FIG. 2, the upper surface extending portion 3a2 (upper surface extending portion 3b2) and the lower surface extending portion 3a3 (lower surface extending portion 3b3) are convexly curved toward the central portions of the upper surface 4a and the lower surface 4b. For example, it is curved in an arc shape toward the center. In FIG. 2, the pair of external electrodes 3 includes a length W1 in the short direction (Y direction) of the stacked body 1 of the upper surface extension portion 3a2 (upper surface extension portion 3b2) as seen in a plan view from the stacking direction. The lower surface extension portion 3a3 (lower surface extension portion 3b3) is provided such that the length W2 in the short direction (Y direction) of the laminate 1 is substantially the same, and the upper surface extension portion 3a2 (upper surface extension) The existing portion 3b2) and the lower surface extending portion 3a3 (lower surface extending portion 3b3) are curved in a convex shape and extend to the upper surface 4a and the lower surface 4b.

  The multilayer capacitor 10 also reduces the area of the upper surface extension 3a2 (upper surface extension 3b2) and the lower surface extension 3a3 (lower surface extension 3b3) located on the upper surface 4a and the lower surface 4b with large vibration amplitude. W1 and W2 are 0.02 with respect to the length of the laminate 1 in the short direction (Y direction) from the viewpoint that vibration is hardly transmitted to the substrate 9 or the mounting stability is improved. It is preferable to be within the range of ~ 0.4.

  The upper surface extension portion 3a2 and the lower surface extension portion 3a3 are such that the length in the longitudinal direction (X direction) of the multilayer body 1 gradually decreases from the first side surface 4e side toward the center portion side of the upper surface 4a and the lower surface 4b. The upper surface 4a and the lower surface 4b are curved in a convex shape so as to protrude toward the center, and have a curved portion that curves toward the center.

  Further, the upper surface extending portion 3b2 and the lower surface extending portion 3b3 are such that the length in the longitudinal direction (X direction) of the laminate 1 is gradually decreased from the second side surface 4f side toward the central portion side of the upper surface 4a and the lower surface 4b. In this way, the upper surface 4a and the lower surface 4b are curved in a convex shape so as to protrude toward the center, and have a curved portion that curves toward the center.

  Thus, the upper surface extending portion 3a2 and the lower surface extending portion 3a3 have a curved portion that curves in a convex shape toward the central portion, and the curved portion is, for example, an arc shape that curves in a convex shape, Similarly, the upper surface extended portion 3b2 and the lower surface extended portion 3b3 have a curved portion that curves in a convex shape toward the central portion side, and the curved portion is For example, an arc shape, a semicircular shape, or a semi-elliptical shape that curves in a convex shape.

  In the multilayer capacitor 10, the upper surface extending portion 3a2 (upper surface extending portion 3b2) and the lower surface extending portion 3a3 (lower surface extending portion 3b3) are curved and extended toward the central portions of the upper surface 1a and the lower surface 1b. Therefore, the external electrode 3 is less likely to be peeled off from the laminated body 1, and cracking or the like is less likely to occur in the solder during soldering, and the mounting reliability can be improved.

  Further, the upper surface extending portion 3a2 (upper surface extending portion 3b2) and the lower surface extending portion 3a3 (lower surface extending portion 3b3) are, for example, a first side surface 4e (second side surface 4f) in plan view from the stacking direction. The shape may be a triangle, trapezoid or quadrilateral polygonal shape with the base as the base (bottom side), and may be in the shape of a triangle, trapezoid or quadrilateral and toward the center of the upper surface 4a and the lower surface 4b. May extend. In addition, the triangular shape or the trapezoidal shape gradually decreases in length along the longitudinal direction of the laminated body 1 toward the central portions of the upper surface 4a and the lower surface 4b. Note that a polygonal shape such as a triangular shape, a trapezoidal shape, or a quadrangular shape includes a case where the corner (vertex) is rounded.

  As shown in FIG. 2, in the first external electrode 3a, the upper surface extension portion 3a2 extends to the upper surface 4a, and the length on the first side surface 4e side along the longitudinal direction of the stacked body 1 is the side surface portion. 3a1 is provided with a length substantially the same as the length of the upper end portion (positive side in the Z direction) side, and the lower surface extension portion 3a3 extends to the lower surface 4b and is the first along the longitudinal direction of the stacked body 1. The length of the side surface 4e is approximately the same as the length of the side surface portion 3a1 on the lower end (negative side in the Z direction) side.

  Specifically, as illustrated in FIG. 2, the upper surface extension portion 3a2 has a length L1 on the first side surface 4e side (a length along the longitudinal direction of the stacked body 1) of the upper end portion of the side surface portion 3a1 ( Provided on the upper surface 4a with a length substantially the same as the length on the positive side in the Z direction, and the lower surface extending portion 3a3 extends along the length L2 on the first side surface 4e side (longitudinal direction of the laminate 1). The length) is provided on the lower surface 4b so as to be substantially the same as the length on the lower end (negative side in the Z direction) side of the side surface portion 3a1.

  In other words, the first external electrode 3a has a length L1 along the longitudinal direction of the stacked body 1 at the ridge line portion between the side surface portion 3a1 and the upper surface extension portion 3a2 between the side surface portion 3a1 and the lower surface extension portion 3a2. It is substantially the same as the length L2 along the longitudinal direction of the laminated body 1 in the ridgeline part between. The length L1 along the longitudinal direction of the multilayer body 1 in the ridge line portion between the side surface portion 3a1 and the upper surface extension portion 3a2 is the first position located in the ridge line portion between the first side surface 4e and the upper surface 4a. The length L2 of the external electrode 3a along the longitudinal direction of the multilayer body 1, and the length L2 along the longitudinal direction of the multilayer body 1 at the ridge line portion between the side surface portion 3a1 and the lower surface extending portion 3a3. It is the length along the longitudinal direction of the laminated body 1 of the first external electrode 3a located at the ridge line portion between the first side surface 4e and the lower surface 4b.

  Similarly, in the second external electrode 3b, the upper surface extension portion 3b2 extends to the upper surface 4a, and the length on the second side surface 4f side along the longitudinal direction of the stacked body 1 is the length of the side surface portion 3b1. The length of the upper surface (the positive side in the Z direction) is approximately the same as the length, and the lower surface extension portion 3b3 extends to the lower surface 4b and is a second side surface along the longitudinal direction of the laminate 1. The length on the 4f side is the same as the length on the lower end (negative side in the Z direction) side of the side surface portion 3b1.

  Specifically, as illustrated in FIG. 2, the upper surface extending portion 3b2 has a length L1 on the second side surface 4f side (a length along the longitudinal direction of the stacked body 1) of the upper end portion of the side surface portion 3b1 ( Provided on the upper surface 4a with a length substantially the same as the length on the positive side in the Z direction, and the lower surface extending portion 3b3 is a length L2 on the second side surface 4f side (in the longitudinal direction of the laminate 1). The length) is provided on the lower surface 4b so as to be substantially the same as the length on the lower end (negative side in the Z direction) side of the side surface portion 3b1.

That is, the second external electrode 3b has a length L1 along the longitudinal direction of the stacked body 1 at the ridge line portion between the side surface portion 3b1 and the upper surface extension portion 3b2, and the length L1 between the side surface portion 3b1 and the lower surface extension portion 3b3. It is substantially the same length as the length L2 along the longitudinal direction of the laminated body 1 in the ridge line part between. Side part 3b
The length L1 along the longitudinal direction of the laminated body 1 in the ridge line portion between the first side surface 1 and the upper surface extension portion 3b2 is the first external position located at the ridge line portion between the second side surface 4f and the upper surface 4a. The length L2 of the electrode 3b along the longitudinal direction of the multilayer body 1 and the length L2 along the longitudinal direction of the multilayer body 1 at the ridge line portion between the side surface portion 3b1 and the lower surface extending portion 3b2 is the second. It is the length along the longitudinal direction of the laminated body 1 of the 2nd external electrode 3b located in the ridgeline part between the side surface 4f and the lower surface 4b.

  In the multilayer capacitor 10, as shown in FIG. 1A, the pair of external electrodes 3 includes a bottom surface extension portion 3 a 3 and a bottom surface extension portion 3 b 3 having thicknesses of the top surface extension portion 3 a 2 and the top surface extension portion 3 b 2. It is thicker than. Specifically, as shown in FIG. 1C, the multilayer capacitor 10 has a lower surface extending by making the thickness of the base electrode 5 provided on the lower surface 4b larger than the thickness of the base electrode 5 provided on the upper surface 4a. The thickness of the existing portion 3a3 and the lower surface extending portion 3b3 is set to be larger than the thickness of the upper surface extending portion 3a2 and the upper surface extending portion 3b2.

  The multilayer capacitor 10 is formed, for example, by adjusting the thickness of the conductive paste 17 serving as the base electrode 5 to be printed or transferred to the multilayer body 1 by using a screen printing method or a roller transfer method, so that the upper surface extending portion 3a2 ( The thickness of the lower surface extension portion 3a3 (lower surface extension portion 3b3) can be made larger than the thickness of the upper surface extension portion 3b2). A method of forming the first external electrode 3a and the second external electrode 3b will be described later.

  As shown in FIG. 1, the internal electrode layer 2 includes a first internal electrode layer 2a and a second internal electrode layer 2b. The first internal electrode layer 2a and the second internal electrode layer 2b are Are opposed to each other at a predetermined interval, and are alternately arranged at a predetermined interval in the stacking direction via a plurality of dielectric layers 1a in the stacked body 1. The internal electrode layer 2 is provided so as to be substantially parallel to the upper surface 4 a and the lower surface 4 b of the multilayer body 1.

  As shown in FIG. 3, the first external electrode 3a is provided such that the side surface portion 3a1 includes the central portion of the first side surface 4e, and the first internal electrode layer 2a led out to the first side surface 4e. Is electrically connected. Further, as shown in FIG. 3, the second external electrode 3b is provided so that the side surface portion 3b1 includes the central portion of the second side surface 4f, and the second internal electrode drawn out to the second side surface 4f. It is electrically connected to the layer 2b.

  As described above, in the multilayer capacitor 10, the first external electrode 3a is provided in the central portion of the first side surface 4e, and the second external electrode 3b is provided in the central portion of the second side surface 4f. As shown in FIG. 3B, the first external electrode 3a is provided so as to cover the extraction portion 2aa of the first internal electrode layer 2a extracted to the first side surface 4e. It is electrically connected to the internal electrode layer 2a. Further, as shown in FIG. 3C, the second external electrode 3b is provided so as to cover the lead portion 2ba of the second internal electrode layer 2b drawn to the second side surface 4f. 2 is electrically connected to the internal electrode layer 2b.

  The central portion of the first side surface 4e is a region including a bisector that bisects the first side surface 4e vertically, and the first external electrode 3a is provided so that the side surface portion 3a1 includes this region. It has been. The central portion of the second side surface 4f is a region including a bisector that bisects the second side surface 4f vertically, and the side portion 3b1 of the second external electrode 3b includes this region. Is provided. In FIG. 3A, the bisector 8 is indicated by a long chain line.

  Thus, the internal electrode layer 2 is electrically connected to different external electrodes 3 for each layer, and a pair of external electrodes 3 connected to different external electrodes 3 by applying a voltage to the pair of external electrodes 3. Capacitance is generated in the dielectric layer 1a sandwiched between the internal electrode layers 2 (the first internal electrode layer 2a and the second internal electrode layer 2b).

  The dimension of the multilayer capacitor 10 having such a configuration is such that the length in the longitudinal direction (X direction) is, for example, 0.6 (mm) to 2.2 (mm), and the length in the short direction (Y direction). However, the length in the height direction (Z direction) is, for example, 0.3 (mm) to 1.5 (mm), for example, 0.3 (mm) to 1.2 (mm).

  The dielectric layer 1a has a rectangular shape in plan view from the stacking direction (Z direction). The structure of the dielectric layer 1a and the internal electrode layer 2 shown in FIG. 1 is a schematic structure. Actually, a structure in which several to several hundreds of dielectric layers 1a and the internal electrode layer 2 are laminated is used. It is often used, and the thickness per layer is, for example, 0.2 (μm) to 3 (μm). In the laminate 1, for example, a plurality of dielectric layers 1 a composed of 10 (layers) to 1000 (layers) and an internal electrode layer 2 are laminated in the Z direction. Further, the number of internal electrode layers 2 in the multilayer body 1 is appropriately set according to the characteristics of the multilayer capacitor 10.

The dielectric layer 1a is, for example, barium titanate (BaTiO ₃ ), calcium titanate (CaTiO ₃ ), strontium titanate (SrTiO ₃ ), or calcium zirconate (CaZrO ₃ ). In addition, it is preferable that the dielectric layer 1a uses barium titanate as a ferroelectric material having a high dielectric constant from the viewpoint of a high dielectric constant.

  As shown in FIG. 3B, the first internal electrode layer 2a has a lead portion 2aa to the first side surface 4e at the center portion on the first side surface 4e side. The first side surface 4e is pulled out and is exposed to the first side surface 4e.

  Further, as shown in FIG. 3C, the second internal electrode layer 2b has a lead portion 2ba to the second side surface 4f at the center portion on the second side surface 4f side, and the lead portion 2ba. Is pulled out to the second side surface 4f opposite to the first side surface 4e and is arranged to be exposed to the second side surface 4f. The first internal electrode layer 2a and the second internal electrode layer 2b are not exposed on the first end face 4c and the second end face 4d.

  In FIG. 3A, the first internal electrode layer 2a exposed on the first side face 4e is indicated by a solid line, and the second internal electrode layer 2b exposed on the second side face 4f is indicated by a broken line. As shown in FIG. 3, the first internal electrode layer 2a and the second internal electrode layer 2b are provided so that the lengths in the longitudinal direction (X direction) of the lead portion 2aa and the lead portion 2ba are substantially the same. ing. The lengths of the lead portion 2aa and the lead portion 2ba along the longitudinal direction (X direction) of the laminate 1 may be different.

  In addition, the drawn portion 2aa (drawer portion 2ba) maintains the symmetry of vibration and can reduce the number of elements that vibrate the substrate during mounting, so that the exposed portion on the first side surface 4e (second side surface 4f). It is preferable that the bisector 8 of the first side face 4e (second side face 4f) is included.

  The conductive material of the internal electrode layer 2 (the first internal electrode layer 2a and the second internal electrode layer 2b) is, for example, nickel (Ni), copper (Cu), silver (Ag), palladium (Pd), or gold ( A metal material such as Au) or an alloy material such as an Ag-Pd alloy including one or more of these metal materials. The first internal electrode layer 2a and the second internal electrode layer 2b have an electrode thickness of, for example, 0.2 (μm) to 2 (μm), and the thickness is appropriately set according to the application. That's fine. The first internal electrode layer 2a and the second internal electrode layer 2b are preferably formed of the same metal material or alloy material.

Thus, the pair of external electrodes 3 (the first external electrode 3a and the second external electrode 3b) are formed on the outer surface (the first side surface 4e and the second side surface) of the laminate 1 as shown in FIG. 4f, upper surface 4a
And the lower surface 4b). The pair of external electrodes 3 (first external electrode 3 a and second external electrode 3 b) includes a base electrode 5 and a metal layer 6. The pair of base electrodes 5 are formed such that one extends from the first side surface 4e to the upper surface 4a and the lower surface 4b, and the other extends from the second side surface 4f to the upper surface 4a and the lower surface 4b. Is formed. The metal layer 6 is formed on the surface of the base electrode 5 so as to cover the base electrode 5.

  One of the pair of base electrodes 5 is electrically connected to the first internal electrode layer 2a drawn to the first side face 4e, and the other is connected to the second internal electrode layer 2b drawn to the second side face 4f. Is electrically connected. The conductive material of the base electrode 5 includes, for example, a metal material such as Cu (copper), nickel (Ni), silver (Ag), palladium (Pd), or gold (Au), or one or more of these metal materials. For example, an alloy material such as a Cu-Ni alloy. Further, the pair of base electrodes 5 is preferably formed on the surface of the laminate 1 with the same metal material or the same alloy material.

  As described above, the first external electrode 3a is composed of the base electrode 5 and the metal layer 6, and is provided from the upper surface 4a to the lower surface 4b including the first side surface 4e. The external electrode 3b is composed of the base electrode 5 and the metal layer 6, and is provided from the upper surface 4a to the lower surface 4b including the second side surface 4f.

  As shown in FIG. 1C, the base electrode 5 is formed on the surface of the multilayer body 1, and the metal layer 6 is formed so as to cover the entire base electrode 5. Further, as shown in FIG. 1C, the metal layer 6 includes a first metal layer 6a and a second metal layer 6b, so that the first metal layer 6a covers the base electrode 5. A second metal layer 6b is formed on the surface of the first metal layer 6a so as to cover the first metal layer 6a.

  The thickness of the base electrode 5 on the upper surface 4a is, for example, 3 (μm) to 5 (μm), and the thickness on the first side surface 4e and the second side surface 4f is, for example, 5 (μm) to 10 (μm). ), And the thickness of the lower surface 4b is larger than the thickness of the upper surface 4a, for example, 5 (μm) to 10 (μm).

  As for the metal layer 6, the 1st metal layer 6a and the 2nd metal layer 6b are formed with a plating layer, for example. The plating layer to be the first metal layer 6a is formed on the surface of the base electrode 5 so as to cover the base electrode 5, and the plating layer to be the second metal layer 6b is the plating layer of the first metal layer 6a. Is formed on the surface of the plating layer of the first metal layer 6a.

  The plating layers of the first metal layer 6a and the second metal layer 6b are, for example, a nickel (Ni) plating layer, a copper (Cu) plating layer, a gold (Au) plating layer, a silver (Ag) plating layer, or tin ( Sn) It is formed of a plating layer or the like. In the multilayer capacitor 10, for example, the first metal layer 6a is a nickel (Ni) plating layer, and the second metal layer 6b is a tin (Sn) plating layer. The plating layer of the first metal layer 6a has a thickness of, for example, 5 (μm) to 10 (μm), and the plating layer of the second metal layer 6b has a thickness of, for example, 3 (μm) to 5 (mu). (Μm).

  As described above, in the multilayer capacitor 10, the pair of external electrodes 3 has the lower surface extension portion 3a3 and the lower surface extension portion 3b3 having a thickness greater than the thicknesses of the upper surface extension portion 3a2 and the upper surface extension portion 3b2. The thickness of the lower surface extension portion 3a3 and the lower surface extension portion 3b3 is, for example, 15 (μm) to 25 (μm), and the thickness of the upper surface extension portion 3a2 and the upper surface extension portion 3b2 is, for example, 10 (μm). ) To 20 (μm).

  Here, the mounting structure of the multilayer capacitor 10 of the first embodiment will be described below.

  FIG. 10A shows a state in which the multilayer capacitor 10 is mounted on the substrate 9, and FIG. 10B shows a state in which the multilayer capacitor 10 is mounted on the substrate 9 in FIG. It is sectional drawing cut | disconnected by the -E line | wire.

  The multilayer capacitor 10 is mounted on a circuit board (hereinafter referred to as a board 9) via, for example, solder. The substrate 9 is used for, for example, a notebook personal computer, a smartphone, a mobile phone, or the like. For example, an electric circuit to which the multilayer capacitor 10 is electrically connected is formed on the surface. The substrate 9 is shown with the insulating layer on the surface omitted.

  As shown in FIG. 10, the substrate 9 is provided with, for example, a substrate electrode 9a and a substrate electrode 9b on the surface on which the multilayer capacitor 10 is mounted, and wiring (not shown) extends from the substrate electrode 9a. In addition, wiring (not shown) extends from the substrate electrode 9b. In the multilayer capacitor 10, for example, the first external electrode 3a and the substrate electrode 9a are solder-bonded via solder, and the second external electrode 3b and the substrate electrode 9b are solder-bonded via solder. . The multilayer capacitor 10 is soldered so that the lower surface 4 b faces the mounting surface of the substrate 9.

  As shown in FIG. 10, the mounting structure of the multilayer capacitor 10 according to the first embodiment includes a first external electrode 3a and a substrate electrode 9a joined together via a conductive material such as solder. The two external electrodes 3b and the substrate electrode 9b are joined via a conductive material such as solder. Solder joining is performed by, for example, solder printed on the substrate electrode 9a and the substrate electrode 9b.

  In the first embodiment, the multilayer capacitor 10 is arranged such that the lower surface 4 b faces the mounting surface of the substrate 9. A solder layer is formed between the first external electrode 3a and the substrate electrode 9a and between the second external electrode 3b and the substrate electrode 9b, and the solder fillet layer 7 along the side surface portion 3a1 and the side surface portion 3b1. Is formed. As shown in FIG. 10B, C is the distance between the mounting surface of the substrate 9 and the multilayer capacitor 10, and H <b> 1 is the height of the solder fillet layer 7 from the mounting surface of the substrate 9. When the multilayer capacitor 10 is mounted by printing solder on the substrate 9, the material used is not particularly limited as long as it has good wettability with the external electrode 3.

  On the other hand, as shown in FIG. 11A, the conventional multilayer capacitor 100 includes a rectangular parallelepiped multilayer body 101 and external electrodes 103 provided on the outer surfaces of both ends thereof. FIG.11 (b) is the top view seen from the Z direction of Fig.11 (a). FIG. 11C is a cross-sectional view taken along line FF in FIG. 11B, and shows a conventional mounting structure of the multilayer capacitor 100 mounted on the substrate 90.

  As shown in FIG. 11C, the laminated body 101 is obtained by alternately laminating dielectric layers 101 a and internal electrode layers 102. The internal electrode layer 102 is electrically connected to the external electrode 103 at either one of both end portions of the multilayer body 101. In the multilayer capacitor 100, the dielectric layer 101a, the internal electrode layer 102, and the external electrode 103 are made of the same material as that of the multilayer capacitor 10 of the first embodiment.

  As shown in FIG. 11C, the conventional multilayer capacitor 100 is fixed in a state in which the external electrode 103 and the substrate electrodes 90a and 90b on the substrate 90 are electrically connected via solder. . Solder fills the gap between the external electrode 103 and the substrate electrodes 90a and 90b, and covers the external electrode 103 that covers the end surface of the laminate 101 and further the side surface and a part of the upper and lower main surfaces to form a solder fillet. Layer 70 is formed. Specifically, the solder fillet layer 70 is formed along both side surfaces of the external electrode 103.

When an AC voltage is applied together with a DC voltage (DC bias) to the multilayer capacitor 100 mounted in such a state, a piezoelectric property is generated in the dielectric layer 101a due to an electrostrictive effect due to the DC voltage, and an AC voltage is generated. Piezoelectric vibration is generated by the voltage. Furthermore, when the piezoelectric vibration of the multilayer capacitor 100 is transmitted to the substrate 90 via the solder fillet layer 70 and the substrate 90 vibrates, and the substrate 90 resonates at an audible resonance frequency, a vibration sound called a squeal is generated. To do.

  Here, a simulation was performed on the piezoelectric vibration of the multilayer capacitor 100 alone. First, impedance was measured in a state where a DC voltage (DC bias) of 4 V was applied to the multilayer capacitor 100. The measurement results are shown in FIG.

  Further, a model based on the multilayer capacitor 100 (dielectric material: barium titanate material, internal electrode layer: Ni, external electrode (base electrode): Cu, multilayer body size: 1100 × 620 × 620 (μm), external electrode The impedance was simulated using a thickness of 20 μm. The material parameters of the multilayer capacitor 100 were fitted so that the piezoelectric resonance peak existing in the frequency region of 2 GHz or more matches the measured actual value. FIG. 13 schematically shows a finite element method model used for impedance simulation. This is a 1/8 model considering symmetry, and the two cross sections appearing on the front surface of FIG. 13 and the lower cross section are symmetry planes.

Table 1 shows parameters (elastic stiffness c _ij and piezoelectric constant e _ij ) of the dielectric layer 101a obtained by the fitting. From Table 1, it can be seen that the material properties of the dielectric layer 101a of the multilayer capacitor 100 have anisotropy (c ₁₁ > c ₃₃ , c ₂₂ > c ₃₃ ). This is considered due to the compressive stress caused by the internal electrode layer 102.

  Further, using the obtained parameters, the vibration mode in the audible frequency region (20 Hz to 20 kHz) of the multilayer capacitor 100 was calculated using the above-mentioned 1/8 model (FIG. 12). FIG. 14 shows the calculation result calculated at 10 kHz. As shown in FIG. 12, the 1/8 model takes symmetry into consideration, and the two cross sections appearing on the entire surface of FIG. 13 and the lower cross section are symmetrical planes. 14 (a) is a view from the inside (symmetrical surface side) of the 1/8 model, and FIG. 14 (b) is the opposite side of FIG. 14 (a), that is, the 1/8 model. Viewed from the outside (front side). Here, the broken line indicates the shape of the multilayer capacitor 100 in a state where no AC voltage is applied, and the solid line indicates the shape of the multilayer capacitor 100 that is displaced to the maximum by the AC voltage.

From this result, it can be seen that, in the audible frequency region, the multilayer capacitor 100 exhibits spreading vibration in the laminated surface direction and stretching vibration in the laminated direction (thickness direction). As schematically shown in FIG. 15 showing the entire multilayer capacitor 100, the multilayer capacitor 100 is configured with a main surface on a pair of main surfaces (upper surface 4 a and lower surface 4 b) located opposite to each other in the stacking direction. It can be seen that a region having a small vibration amplitude, that is, a node of vibration (hereinafter referred to as a node-like portion 15) exists at the center of each side.

  Since the multilayer capacitor 10 according to the first embodiment is equivalent to the multilayer capacitor 100, the above-described nodal portion 15 exists at the center of each side, as with the multilayer capacitor 100. Therefore, in the multilayer capacitor 10, when the pair of external electrodes 3 are fixed to the substrate 9 via the solder at the node portion 15, the propagation of piezoelectric vibration to the substrate 9 is suppressed, and the noise can be reduced. Conceivable.

  As shown in FIG. 14B, the multilayer capacitor 10 has the above-described nodal portion 15, and the first external electrode 3 a and the second external electrode 3 b are provided in the nodal portion 15. Therefore, it is fixed to the substrate 9 by the node-like portion 15.

  The pair of external electrodes 3 is provided on the first side surface 4e so that the first external electrode 3a includes the node-shaped portion 15, and extends to the upper surface 4a and the lower surface 4b. Similarly, the second external electrode 3a The electrode 3b is provided on the second side surface 4f so as to include the node-like portion 15, and extends to the upper surface 4a and the lower surface 4b.

  The pair of external electrodes 3 is provided on the first side surface 4e so that the first external electrode 3a is located inside the node-like portion 15, extends to the upper surface 4a and the lower surface 4b, and the second The external electrode 3b may be provided on the second side surface 4f so as to be located inside the node-like portion 15, and may extend to the upper surface 4a and the lower surface 4b.

  Here, an example of a method for forming the pair of external electrodes 3 of the multilayer capacitor 10 will be described with reference to FIG.

  In the pair of base electrodes 5, the conductive paste 17 to be the base electrode 5 is provided on the first side surface 4e (second side surface 4f), the upper surface 4a, and the lower surface 4b using a roller transfer method.

  As shown in FIG. 16, by adjusting the feeding speed of the laminated body 1 and the rotational speed of the rotary transfer roller 16, the conductive paste 17 accumulates on the upper surface 4a and the lower surface 4b of the laminated body 1, and the first The conductive paste 17 to be the base electrode 5 is transferred to the laminated body 1 on the side surface 4e and the second side surface 4f. Thus, the conductive paste 17 to be the base electrode 5 is provided on the first side surface 4e (second side surface 4f), and the conductive paste 17 to be the base electrode 5 is provided to extend to the upper surface 4a. In addition, the conductive paste 17 to be the base electrode 5 is provided so as to extend to the lower surface 4b.

  Further, the multilayer capacitor 10 has, for example, a relationship in which the feeding speed of the laminated body 1 and the rotational speed of the rotary transfer roller 16 are in a relationship of the feeding speed of the laminated body 1 = the rotational speed of the rotary transfer roller 16 = 1000: 1002 to 1004 By making the rotation speed of the rotary transfer roller 16 larger than the feeding speed of the laminated body 1, the thickness of the base electrode 5 provided on the lower surface 4b can be made larger than the thickness of the base electrode 5 provided on the upper surface 4a. The shapes of the upper surface extension portion 3a2 (upper surface extension portion 3b2) and the lower surface extension portion 3b2 (lower surface extension portion 3b3) are reflected in the shape of the base electrode 5.

  The conductive paste 17 is supplied from the injection needle 18 to the rotary transfer roller 16, and the film thickness is adjusted by the scraper 19. After the conductive paste 17 is sintered to form the base electrode 5, the metal layer 6 is provided so as to cover the surface of the base electrode 5, thereby forming a pair of external electrodes 3.

Thus, in the multilayer capacitor 10 according to the first embodiment, the pair of external electrodes 3
The side surface portion 3a1 includes the central portion of the first side surface 4e and does not include both end portions, and the side surface portion 3b1 includes the central portion of the second side surface 4f and does not include both end portions. Further, the thickness of the lower surface extending portion 3a3 and the lower surface extending portion 3b3 is larger than the thickness of the upper surface extending portion 3a2 and the upper surface extending portion 3b2.

  The multilayer capacitor 10 has a region having a relatively small vibration amplitude including the node-like portion 15 at the center of the long sides of the upper surface 4a and the lower surface 4b. That is, the multilayer capacitor 10 has a ridge line portion between the upper surface 4a and the lower surface 4b and the first side surface 4e, and a ridge line portion between the upper surface 4a and the lower surface 4b and the second side surface 4f. The center portion has a region having a relatively small vibration amplitude including the node-shaped portion 15, and the first external electrode 3 a and the second external electrode 3 b include the node-shaped portion 15 and have a relatively small vibration amplitude. Since it is provided in the area, it is possible to suppress the noise.

  Furthermore, in the multilayer capacitor 10, since the thickness of the lower surface extending portion 3a2 and the lower surface extending portion 3b2 facing the mounting surface of the substrate 9 is large, the gap between the multilayer body 1 and the mounting surface of the substrate 9 is large. Thus, the propagation of piezoelectric vibration to the substrate 9 is suppressed, and the noise is reduced.

  As shown in FIG. 6, the multilayer capacitor 10 </ b> B can increase the thickness of the lower surface extension portion 3 a 3 and the lower surface extension portion 3 b 3 by providing the resin layer 11 on the pair of external electrodes 3. Specifically, in the pair of external electrodes 30, a resin layer 11 made of a conductive resin is provided between the base electrode 5 and the metal layer 6, and the thickness of the resin layer 11 provided on the lower surface 4b is provided on the upper surface 4a. By making it thicker than the thickness of the resin layer 11, the thickness of the lower surface extending portion 3a3 and the lower surface extending portion 3b3 can be increased. The resin layer 11 is provided using, for example, a roller transfer method so as to cover the surface of the base electrode 5. The base electrode 5 has a thickness on the upper surface 4a of, for example, 3 (μm) to 5 (μm), and a thickness on the first side surface 4e and the second side surface 4f of, for example, 5 (μm) to 10 (mu). The thickness of the lower surface 4b is, for example, 3 (μm) to 5 (μm).

  The resin layer 11 has a thickness on the upper surface 4a of, for example, 20 (μm) to 40 (μm), and a thickness of the first side surface 4e and the second side surface 4f of, for example, 40 (μm) to 60 (μm). ), And the thickness of the lower surface 4b is larger than the thickness of the upper surface 4a, for example, 60 (μm) to 80 (μm). In the multilayer capacitor 10B, the pair of external electrodes 3 has a lower surface extension portion 3a3 and a lower surface extension portion 3b3 that are thicker than the upper surface extension portion 3a2 and the upper surface extension portion 3b2. The thickness of the part 3a3 and the lower surface extension part 3b3 is, for example, 70 (μm) to 100 (μm), and the thickness of the upper surface extension part 3a2 and the upper surface extension part 3b2 is, for example, 30 (μm) to 60 ( μm).

  Thus, the multilayer capacitor 10 </ b> B can relieve vibration by the resin layer 11 by providing the resin layer 11 between the base electrode 5 and the metal layer 6.

  The resin layer 11 is made thicker than the resin layer 11 provided on the upper surface 4a by making the rotational speed of the rotary transfer roller 16 larger than the feeding speed of the laminated body 1, thereby making the resin layer 11 provided on the lower surface 4b thicker. can do.

  Further, the resin layer 11 is a conductive resin, for example, a resin material such as an epoxy resin, a silicone resin, or a urethane resin, and as a conductive material, for example, nickel (Ni), copper (Cu), silver (Ag) , A powder (filler) of a metal material such as platinum (Pt), palladium (Pd), or gold (Au), or a powder of an alloy material such as an Ag-Pd alloy (eg, one or more of these metal materials) Filler) is included.

  The present invention is not limited to the multilayer capacitor 10 of the first embodiment described above, and various modifications and improvements can be made without departing from the scope of the present invention. Hereinafter, other embodiments will be described. Note that, among the multilayer capacitors according to other embodiments, the same portions as those of the multilayer capacitor 10 according to the first embodiment are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

<Embodiment 2>
Hereinafter, a multilayer capacitor 10A according to Embodiment 2 of the present invention will be described with reference to FIGS. 4 is a drawing corresponding to FIG. 1C, and FIG. 5 is a drawing corresponding to FIG. The multilayer capacitor 10A is different from the multilayer capacitor 10 in the size of the lower surface extending portion 3a2 (lower surface extending portion 3b2), that is, the upper surface extending portion 3a2 (upper surface extending portion 3b2) and the lower surface extending portion 3b3 (lower surface). The extending portions 3b3) have different lengths along the short direction of the laminate 1.

  In the multilayer capacitor 10A, the front end portions of the lower surface extension portion 3a3 and the lower surface extension portion 3b3 are seen in a plan view from the stacking direction, and the center portion of the lower surface 4b is more than the front end portions of the upper surface extension portion 3a2 and the upper surface extension portion 3b2. Located on the side. That is, as shown in FIG. 5, the pair of external electrodes 3 has a length W2 extending along the short side direction (Y direction) of the laminate 1 of the lower surface extending portion 3a3 (lower surface extending portion 3b3). The upper surface extension portion 3a2 (upper surface extension portion 3b2) and the lower surface extension so as to be longer than the length W1 along the short direction (Y direction) of the stacked body 1 of the portion 3a2 (upper surface extension portion 3b2). The portion 3a3 (lower surface extending portion 3b3) is convexly curved and extends to the upper surface 4a and the lower surface 4b, respectively.

  Therefore, in the multilayer capacitor 10A, in the pair of external electrodes 3, the length W2 of the lower surface extension portion 3a3 (lower surface extension portion 3b3) is larger than the length W1 of the upper surface extension portion 3a2 (upper surface extension portion 3b2). Largely, W2> W1. Further, the relationship of W1: W2 = 1: 1.5 to 2 is preferable from the viewpoint of suppression of noise and mounting stability.

  For example, the feeding speed of the laminated body 1 and the rotational speed of the rotary transfer roller 16 are in the relationship of the feeding speed of the laminated body 1: the rotational speed of the rotary transfer roller 16 = 1000: 1004 to 1006. The rotational speed is larger than the feed speed of the laminate 1. When the feeding speed of the laminated body 1 is slow with respect to the rotational speed of the rotary transfer roller 16, the conductive paste 17 serving as the base electrode 5 tends to accumulate behind the feeding, and the conductive paste 17 is difficult to be supplied in front of the feeding. Become. Thus, by making the rotational speed of the rotary transfer roller 16 larger than the feeding speed of the laminated body 1, the length of the lower surface extending portion 3a3 (lower surface extending portion 3b3) along the short direction of the laminated body 1. W2 is larger than the length W1 of the upper surface extension portion 3a2 (upper surface extension portion 3b2) along the short direction of the multilayer body 1, and W2> W1, and the upper surface extension portion 3a2 (upper surface extension) of the multilayer capacitor 10A is satisfied. The existing portion 3b2) and the lower surface extending portion 3a3 (lower surface extending portion 3b3) can be formed on the upper surface 4a and the lower surface 4b, respectively.

  The conductive paste 17 is supplied from the injection needle 18 to the rotary transfer roller 16, and the film thickness is adjusted by the scraper 19. After the conductive paste 17 is sintered to form the base electrode 5, the metal layer 6 is provided so as to cover the surface of the base electrode 5, thereby forming a pair of external electrodes 3.

  Thus, in the pair of external electrodes 3 (first external electrode 3a and second external electrode 3b), the areas of the lower surface extension portion 3a3 and the lower surface extension portion 3b3 facing the mounting surface of the substrate 9 are increased. As a result, the bonding area between the substrate electrodes 9a and 9b is increased, and the multilayer capacitor 10A is stably mounted on the substrate 9. Therefore, the multilayer capacitor 10A can suppress noise and improve mounting stability and mounting reliability.

<Embodiment 3>
Hereinafter, a multilayer capacitor 10C according to Embodiment 3 of the present invention will be described with reference to FIG.

  In the multilayer capacitor 10C, as shown in FIG. 7C, the thickness of the side surface portion 3a1 and the side surface portion 3b1 of the pair of external electrodes 3 extends from the bottom surface extending portion 3a3 side to the bottom surface extending portion 3b3 side. It is thicker than the thickness on the side of the portion 3a2 and the upper surface extending portion 3b2. Specifically, in the multilayer capacitor 10C, as shown in FIG. 7C, the thickness of the base electrode 5 provided on the lower surface extension portion 3a3 (lower surface extension portion 3b3) side is set to the upper surface extension portion 3a2 (upper surface portion). By making it thicker than the thickness of the base electrode 5 provided on the extending portion 3b2) side, the thickness of the side surface portion 3a1 on the lower surface extending portion 3a3 side can be increased, and the lower surface extending portion of the side surface portion 3b1. The thickness on the 3b3 side can be increased.

  In this way, as shown in FIG. 7C, the pair of external electrodes 3 has a large thickness so that the side surface portion 3a1 protrudes outward (the negative side in the Y direction) on the lower surface extension portion 3a3 side. In addition, the thickness is increased so that the side surface portion 3b3 protrudes outward (positive side in the Y direction) on the lower surface extending portion 3b3 side. In the multilayer capacitor 10 </ b> C, the side surface portion 3 a 1 (side surface portion 3 b 1) has a shape that gradually increases in thickness in a region located on the lower side when the multilayer body 1 is divided into three in the stacking direction. In the multilayer capacitor 10C, the thickness of the side surface portion 3a1 (side surface portion 3b1) gradually increases on the lower side, whereby the mounting stability when mounted on the substrate 9 is improved and the gentle solder fillet layer 7 is formed. It becomes easy to relieve stress, and the occurrence of cracks and the like is suppressed.

  The thickness of the base electrode 5 in the central portion in the stacking direction (Z direction) is, for example, 5 (μm) to 10 (μm), and the thickness in the lower end portion in the stacking direction (Z direction) is larger than the thickness in the central portion. It is thick, for example, 60 (μm) to 80 (μm).

  That is, as shown in FIG. 7C, the side surface portion 3a1 (side surface portion 3b1) is thicker at the lower end portion in the stacking direction (Z direction) than the thickness at the central portion, and the side surface portion 3a1 (side surface portion) The thickness of the portion 3b1) in the central portion in the stacking direction (Z direction) is, for example, 55 (μm) to 85 (μm), and the thickness in the lower end portion in the stacking direction (Z direction) is, for example, 70 (μm). ) To 100 (μm).

  As described above, the side surface portion 3a1 and the side surface portion 3b1 of the pair of external electrodes 3 have the thicknesses on the lower surface extension portion 3a3 side and the lower surface extension portion 3b3 side that are on the upper surface extension portion 3a2 side and the upper surface extension portion 3b2 side. Since the thickness of the multilayer capacitor 10C is lower, the mounting stability is improved. In the multilayer capacitor 10C, the gentle solder fillet layer 7 is easily formed, the stress is easily relieved, and the occurrence of cracks and the like is suppressed.

  In the multilayer capacitor 10C, the thickness of the side surface portion 3a1 (side surface portion 3b1) is greater on the lower surface extension portion 3a3 (lower surface extension portion 3b3) side than the upper surface extension portion 3a2 (upper surface extension portion 3b2) side. However, the cross-sectional shape of the side surface portion 3a1 (side surface portion 3b1) is not limited to this.

  For example, as shown in FIG. 8 (a), the multilayer capacitor 10D includes a pair of external electrodes 3 whose upper surface extending portion 3a2 (upper surface extension) has a thickness of the side surface portion 3a1 (side surface portion 3b1) in the stacking direction (Z direction). You may provide in the shape which becomes thick gradually as it goes to the lower surface extension part 3a3 (lower surface extension part 3b3) side from the existing part 3b2) side.

In the side surface portion 3a1 (side surface portion 3b1), the thickness at the lower end portion in the stacking direction (Z direction) is thicker than the thickness at the central portion, and the lower surface extends from the upper surface extension portion 3a2 (upper surface extension portion 3b2) side. By making the shape gradually thicker toward the part 3a3 (lower surface extending part 3b3) side, the multilayer capacitor 10D has a lower center of gravity and improved mounting stability, and the solder fillet layer 7 Since the shape becomes gentle, the concentration of stress on the solder is eased.

  Further, as shown in FIG. 8B, the multilayer capacitor 10E includes a resin layer 11 provided on the lower surface extension portion 3a3 (lower surface extension portion 3b3) side by providing the resin layer 11 on the pair of external electrodes 3. 11 is made thicker than the thickness of the resin layer 11 provided on the upper surface extension portion 3a2 (upper surface extension portion 3b2) side, thereby the thickness of the side surface portion 3a1 on the lower surface extension portion 3a3 side and the lower surface of the side surface portion 3b1. The thickness on the extending portion 3b3 side can be increased. In the multilayer capacitor 10E, the side surface portion 3a1 (side surface portion 3b1) is shaped so that the thickness gradually increases in a region located on the lower side when the multilayer body 1 is divided into three in the stacking direction. In the multilayer capacitor 10E, the thickness of the side surface portion 3a1 (side surface portion 3b1) gradually increases on the lower side, whereby the mounting stability when mounted on the substrate 9 is improved and the gentle solder fillet layer 7 is formed. It becomes easy to relieve stress, and the occurrence of cracks and the like is suppressed.

  The resin layer 11 has a thickness in the central portion in the stacking direction (Z direction) of, for example, 45 (μm) to 65 (μm), and the thickness in the lower end portion in the stacking direction (Z direction) is larger than the thickness in the central portion. It is thick, for example, 60 (μm) to 80 (μm). The base electrode 5 has a thickness on the upper surface 4a of, for example, 3 (μm) to 5 (μm), and a thickness on the first side surface 4e and the second side surface 4f of, for example, 5 (μm) to 10 (mu). The thickness of the lower surface 4b is, for example, 3 (μm) to 5 (μm).

  That is, as shown in FIG. 8B, the side surface portion 3a1 (side surface portion 3b1) has a thickness at the lower end portion in the stacking direction (Z direction) larger than the thickness at the central portion, and the side surface portion 3a1 (side surface portion) The thickness of the portion 3b1) in the central portion in the stacking direction (Z direction) is, for example, 55 (μm) to 85 (μm), and the thickness in the lower end portion in the stacking direction (Z direction) is, for example, 70 (μm). ) To 100 (μm).

  Thus, the multilayer capacitor 10 </ b> E can relieve vibration by the resin layer 11 by providing the resin layer 11 between the base electrode 5 and the metal layer 6. Furthermore, since the multilayer capacitor 10E has a large thickness on the lower surface extension portion 3a3 (lower surface extension portion 3b3) side, propagation of vibration to the substrate can be suppressed.

  In the multilayer capacitor 10C to the multilayer capacitor 10E, the length W2 along the short side direction of the multilayer body 1 of the lower surface extension portion 3a3 (lower surface extension portion 3b3) is the upper surface extension portion 3a2 (upper surface extension portion). It may be larger than the length W1 along the short direction of the laminate 1 in 3b2), and W2> W1 may be satisfied.

  Further, the multilayer capacitor 10E is provided with a resin layer 11 made of a conductive resin between the base electrode 5 and the metal layer 6, and the thickness of the side surface portion 3a1 (side surface portion 3b1) is increased in the stacking direction (Z direction). It is also possible to make the shape gradually thicker from the extending portion 3a2 (upper surface extending portion 3b2) side toward the lower surface extending portion 3a3 (lower surface extending portion 3b3) side.

<Embodiment 4>
Hereinafter, the multilayer capacitor 10F according to the fourth embodiment of the present invention will be described with reference to FIG. Unlike the multilayer capacitor 10, the multilayer capacitor 10 </ b> F is provided so that the pair of external electrodes 3 includes the center portions of the first end surface 4 c and the second end surface 4 d. In the multilayer capacitor 10F, the pair of external electrodes 3 are provided on the pair of end surfaces 4c and 4d, but other configurations such as the shape of the pair of external electrodes 3 are the same as those of the multilayer capacitor 10.

  In addition, the technical content applied in the multilayer capacitor 10 to the multilayer capacitor 10E described above can be appropriately employed for the multilayer capacitor 10F. The first external electrode 3A and the second external electrode 3B can be provided on the first end surface 4c and the second end surface 4d by using the above-described roller transfer method or the like.

  FIG. 9A is a schematic perspective view showing a multilayer capacitor 10F according to Embodiment 4 of the present invention. The multilayer capacitor 10F includes a dielectric layer 1a and an internal electrode layer 2 (first internal electrode). The rectangular parallelepiped laminated body 1 in which the layers 2a and the second internal electrode layers 2b) are alternately laminated, and the pair of end faces 4c and 4d in the longitudinal direction of the laminated body 1 are provided on the internal electrode layers 2 different from each other. And a pair of external electrodes 3 (first external electrode 3A and second external electrode 3B) that are electrically connected to each other.

  As shown in FIG. 9, the pair of external electrodes 3 includes a first external electrode 3A and a second external electrode 3B. The first external electrode 3A has a side surface portion 3A1, an upper surface extending portion 3A2, and a lower surface extending portion 3A3, and the first end surface so that the side surface portion 3A1 includes the central portion of the first end surface 4c. 4c, the upper surface extending portion 3A2 extends from the side surface portion 3A1 toward the central portion in the longitudinal direction (X direction) of the multilayer body 1 on the upper surface 4a, and the lower surface extending portion 3A3 is stacked from the side surface portion 3A1. The body 1 extends on the lower surface 4b toward the center in the longitudinal direction (X direction).

  The second external electrode 3B has a side surface portion 3B1, an upper surface extension portion 3B2, and a lower surface extension portion 3B3, and the second side electrode 3B1 includes the center portion of the second end surface 4d. The upper surface extending portion 3B2 extends on the upper surface 4a from the side surface portion 3B1 toward the central portion in the longitudinal direction (X direction) of the stacked body 1, and the lower surface extending portion 3B3 is formed on the side surface portion 3B1. Extends on the lower surface 4b toward the center of the laminate 1 in the longitudinal direction (X direction).

  In the first external electrode 3A, the upper surface extension portion 3A2 has a length on the first end surface 4c side substantially equal to the length on the upper end portion (positive side in the Z direction) side of the side surface portion 3A1 on the upper surface 4a. The lower surface extending portion 3A3 is provided on the lower surface 4b so that the length on the first end surface 4c side is substantially the same as the length on the lower end portion (negative side in the Z direction) side of the side surface portion 3A1. Yes.

  In the second external electrode 3B, the upper surface extending portion 3B2 has an upper surface whose length on the second end surface 4d side is substantially the same as the length on the upper end portion (positive side in the Z direction) side of the side surface portion 3B1. The lower surface extending portion 3B3 is provided on the lower surface 4b so that the length on the second end surface 4d side is substantially the same as the length on the lower end (negative side in the Z direction) side of the side surface portion 3B1. It has been.

  The pair of external electrodes 3 is provided on the first end surface 4c so that the first external electrode 3A includes the node-like portion 15, and extends to the upper surface 4a and the lower surface 4b. Similarly, the second external electrode 3A The electrode 3B is provided on the second end surface 4d so as to include the node-like portion 15, and extends to the upper surface 4a and the lower surface 4b.

  The pair of external electrodes 3 is provided on the first end surface 4c so that the first external electrode 3A is located inside the node-like portion 15, and extends to the upper surface 4a and the lower surface 4b. The external electrode 3B may be provided on the second end surface 4d so as to be located inside the node-like portion 15, and may extend to the upper surface 4a and the lower surface 4b.

The upper surface extension portion 3A2 (upper surface extension portion 3B2) and the lower surface extension portion 3A3 (lower surface extension portion 3B3) are curved in a convex shape toward the central portions of the upper surface 4a and the lower surface 4b. It is curved and extends in a circular arc shape. In addition, the pair of external electrodes 3 includes a length W3 and a bottom surface extension portion along the longitudinal direction (X direction) of the multilayer body 1 of the top surface extension portion 3A2 (top surface extension portion 3B2) as seen in a plan view from the stack direction. 3A3 (lower surface extension portion 3B3) is provided so that the length W4 along the longitudinal direction (X direction) of the laminate 1 is substantially the same, and the upper surface extension portion 3A2 (upper surface extension portion 3B2). ) And the lower surface extending portion 3A3 (lower surface extending portion 3B3) are curved in a convex shape and extend to the upper surface 4a and the lower surface 4b.

  Further, the multilayer capacitor 10F reduces the areas of the upper surface extension 3A2 (upper surface extension 3B2) and the lower surface extension 3A3 (lower surface extension 3B3) located on the upper surface 4a and the lower surface 4b having large vibration amplitude. W3 and W4 are 0.02 to the length in the longitudinal direction (X direction) of the laminate 1 from the viewpoint of making it difficult to transmit vibration to the substrate 9 or improving the mounting stability. It is preferable to be within the range of 0.4.

  Further, in the multilayer capacitor 10F, the tip end portion of the lower surface extension portion 3A3 (lower surface extension portion 3B3) is lower than the tip portion of the upper surface extension portion 3A2 (upper surface extension portion 3B2) as seen in a plan view from the stacking direction. You may be located in the center part side of 4b. That is, the pair of external electrodes 3 is a laminate in which the length W4 along the longitudinal direction of the laminate 1 of the lower surface extension portion 3A3 (lower surface extension portion 3B3) is the upper surface extension portion 3A2 (upper surface extension portion 3B2). It may be larger than the length W3 along the longitudinal direction of 1 and W4> W3. Further, the relationship of W3: W4 = 1: 1.5 to 2 is preferable from the viewpoint of suppression of noise and mounting stability.

  In the multilayer capacitor 10F, as in the multilayer capacitor 10, the upper surface extending portion 3A2 and the lower surface extending portion 3A3 are formed such that the length in the short direction (Y direction) of the multilayer body 1 is the upper surface from the first end surface 4c side. 4a and the lower surface 4b are convexly curved so as to protrude toward the central portion side of the upper surface 4a and the lower surface 4b so as to gradually decrease toward the central portion side, and bend and extend toward the central portion side. It has a curved part.

  In addition, the upper surface extending portion 3B2 and the lower surface extending portion 3B3 are such that the length in the short direction (Y direction) of the multilayer body 1 gradually increases from the second end surface 4d side toward the central portion side of the upper surface 4a and the lower surface 4b. The upper surface 4a and the lower surface 4b are curved in a convex shape so as to protrude toward the center, and have a curved portion that curves and extends toward the center.

  Thus, the upper surface extending portion 3A2 and the lower surface extending portion 3A3 have a curved portion that curves in a convex shape toward the central portion, and the curved portion is, for example, an arc shape that curves in a convex shape, Similarly, the upper surface extended portion 3B2 and the lower surface extended portion 3B3 have a curved portion that curves in a convex shape toward the center side, and the curved portion is For example, an arc shape, a semicircular shape, or a semi-elliptical shape that curves in a convex shape.

  In the multilayer capacitor 10F, the upper surface extending portion 3a2 (upper surface extending portion 3b2) and the lower surface extending portion 3a3 (lower surface extending portion 3b3) are curved and extended toward the central portions of the upper surface 1a and the lower surface 1b. Therefore, the external electrode 3 is less likely to be peeled off from the laminated body 1, and cracking or the like is less likely to occur in the solder during soldering, and the mounting reliability can be improved.

The upper surface extending portion 3A2 (upper surface extending portion 3B2) and the lower surface extending portion 3A3 (lower surface extending portion 3B3) are, for example, a first end surface 4c (second end surface 4d) in plan view from the stacking direction. May be in the shape of a triangle, trapezoid or quadrilateral polygon, etc. with the base (bottom) as the base, and toward the center of the upper surface 4a and the lower surface 4b in the shape of a triangle, trapezoid or quadrangle. It may be extended. Further, in the triangular shape or the trapezoidal shape, the length along the short direction of the laminated body 1 is gradually reduced toward the central portions of the upper surface 4a and the lower surface 4b. Note that a polygonal shape such as a triangular shape, a trapezoidal shape, or a quadrangular shape includes a case where the corner (vertex) is rounded.

  In the multilayer capacitor 10F, similarly to the multilayer capacitor 10, the thickness of the lower surface extension portion 3A3 and the lower surface extension portion 3B3 is larger than the thickness of the upper surface extension portion 3A2 and the lower surface extension portion 3B2. Specifically, the multilayer capacitor 10F is configured such that the thickness of the base electrode 5 provided on the lower surface 4b is larger than the thickness of the base electrode 5 provided on the upper surface 4a, so that the lower surface extension portion 3A3 and the lower surface extension portion 3B3 are formed. The thickness can be increased. In this case, the base electrode 5 provided on the lower surface 4b has a thickness of the base electrode 5 provided on the lower surface 4b on the upper surface 4a by making the rotational speed of the rotary transfer roller 16 larger than the feeding speed of the laminate 1. It can be made thicker than the thickness of the underlying electrode 5 provided. Further, a resin layer 11 made of a conductive resin is provided between the base electrode 5 and the metal layer 6 so that the thickness of the resin layer 11 provided on the lower surface 4b is larger than the thickness of the resin layer 11 provided on the upper surface 4a. Thus, the thickness of the lower surface extending portion 3A3 and the lower surface extending portion 3B3 can be increased.

  In the multilayer capacitor 10F, for example, the first external electrode 3A and the substrate electrode 9a are solder-bonded via solder, and the second external electrode 3B and the substrate electrode 9b are solder-bonded via solder. Is done. In the soldered multilayer capacitor 10 </ b> D, the lower surface 4 b faces the mounting surface of the substrate 9.

  Unlike the multilayer capacitor 10 to the multilayer capacitor 10E, the multilayer capacitor 10F is provided so that the pair of external electrodes 3 includes the central portions of the first end surface 4c and the second end surface 4d. Also in the multilayer capacitor 10F according to the fourth embodiment, the configuration as in the second to third embodiments can be applied.

  As described above, unlike the multilayer capacitors 10 to 10E, the multilayer capacitor 10F is provided such that the pair of external electrodes 3 includes the central portions of the first end surface 4c and the second end surface 4d. However, other configurations have the same configuration, and the same effects as the multilayer capacitor 10 to the multilayer capacitor 10E can be obtained.

  The present invention is not particularly limited to the above-described embodiments, and various changes and improvements can be made within the scope of the present invention. For example, the side portions of the pair of external electrodes may have different shapes within the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Laminated body 1a Dielectric layer 2 Internal electrode layer 2a 1st internal electrode layer 2aa Lead part 2b 2nd internal electrode layer 2ba Lead part 3 External electrode 3a, 3A 1st external electrode 3a1, 3A1 Side face part 3a2, 3A2 Upper surface extending portion 3a3, 3A3 Lower surface extending portion 3b, 3B Second external electrode 3b1, 3B1 Side surface portion 3b2, 3B2 Upper surface extending portion 3b3, 3B3 Lower surface extending portion 4a Upper surface 4b Lower surface 4c First end surface 4d Second End face 4e first side face 4f second side face 5 ground electrode 6 metal layer 6a first metal layer 6b second metal layer 7 solder fillet layer 8 bisector 9 substrate 9a, 9b substrate electrode 10, 10A- 10F Multilayer Capacitor 11 Resin Layer 15 Node 16 Rotating Transfer Roller 17 Conductive Paste 18 Injection Needle 19 Scraper

Claims (13)

A rectangular parallelepiped laminate in which dielectric layers and internal electrode layers are alternately laminated, and a pair of external electrodes provided on the outer surface of the laminate and electrically connected to the different internal electrode layers, respectively. And
The laminated body includes a rectangular upper surface and a lower surface facing each other, positioned in the stacking direction of the dielectric layer and the internal electrode layer, a pair of side surfaces adjacent to the long side of the upper surface and the lower surface, A pair of end surfaces adjacent to the short side of the upper surface and the lower surface,
The pair of external electrodes includes a side surface portion provided on the side surface so as to include a center portion of the side surface, an upper surface extending portion extending from the side surface portion to the upper surface, and extending from the side surface portion to the lower surface. A lower surface extending portion,
The multilayer capacitor according to claim 1, wherein the external electrode has a thickness of the lower surface extending portion that is greater than a thickness of the upper surface extending portion.   The length of the upper surface extension portion and the lower surface extension portion along the longitudinal direction of the laminate gradually decreases toward the center portion of the upper surface and the lower surface. The multilayer capacitor described.   The said upper surface extension part and the said lower surface extension part are curving and extended in the convex shape toward the center part of the said upper surface and the said lower surface, The Claim 1 or Claim 2 characterized by the above-mentioned. Multilayer capacitor.   The tip portion of the lower surface extending portion is located on the center side of the lower surface from the tip portion of the upper surface extending portion as seen in a plan view from the stacking direction. A multilayer capacitor according to any one of the above.   5. The multilayer capacitor according to claim 1, wherein the side surface portion has a thickness on the lower surface extension portion side larger than a thickness on the upper surface extension portion side.   6. The multilayer capacitor according to claim 1, wherein the side surface portion gradually increases in thickness from the upper surface extension portion side toward the lower surface extension portion side. A rectangular parallelepiped laminate in which dielectric layers and internal electrode layers are alternately laminated, and a pair of external electrodes provided on the outer surface of the laminate and electrically connected to the different internal electrode layers, respectively. And
The laminated body includes a rectangular upper surface and a lower surface facing each other, positioned in the stacking direction of the dielectric layer and the internal electrode layer, a pair of side surfaces adjacent to the long side of the upper surface and the lower surface, A pair of end surfaces adjacent to the short side of the upper surface and the lower surface,
The external electrode includes an end surface portion provided on the end surface so as to include a central portion of the end surface, an upper surface extending portion extending from the end surface portion to the upper surface, and a lower surface extension extending from the end surface portion to the lower surface. Have
The multilayer capacitor according to claim 1, wherein the external electrode has a thickness of the lower surface extending portion that is greater than a thickness of the upper surface extending portion.   The length of the upper surface extending portion and the lower surface extending portion along the short direction of the stacked body is gradually reduced toward the center portion of the upper surface and the lower surface. The multilayer capacitor described in 1. The said upper surface extension part and the said lower surface extension part are curving and extended in convex shape toward the center part of the said upper surface and the said lower surface, The Claim 7 or Claim 8 characterized by the above-mentioned. Multilayer capacitor.   The front end portion of the lower surface extending portion is located closer to the center of the lower surface than the front end portion of the upper surface extending portion as seen in a plan view from the stacking direction. A multilayer capacitor according to any one of the above.   11. The multilayer capacitor according to claim 7, wherein the side surface portion has a thickness on the lower surface extension portion side larger than a thickness on the upper surface extension portion side.   12. The multilayer capacitor according to claim 7, wherein the side surface portion gradually increases in thickness from the upper surface extension portion side toward the lower surface extension portion side. The multilayer capacitor according to any one of claims 1 to 12 and a substrate are arranged so that the lower surface and a mounting surface of the substrate face each other, and are joined via the pair of external electrodes. A mounting structure characterized by that.