JP2016219741A - Laminated capacitor and mounting structure thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated capacitor suppressing propagation of vibration to a substrate.SOLUTION: A laminated capacitor 10 comprises: a substantially rectangular parallelepiped laminate 1 to which an internal electrode 2 and a dielectric layer 1a are laminated; and first and second external electrodes 3a and 3b which are connected to different internal electrode 2 from each other. The laminate 1 includes a pair of rectangular principal surfaces 4a and 4b positioned in a lamination direction; and a pair of end surfaces 4c and 4d adjacent to a short side of the principal surfaces 4a and 4b. The first external electrode 3a includes a first external electrode side surface part 3a1 provided in a central part of the end surface 4c; and a first extended part 3a2 extended on the pair of principal surfaces. The second external electrode 3b includes: a second external electrode side surface part 3b1 provided in the central part of end surface 4d; and a second extended part 3b2 extended on the pair of principal surfaces. A length of the first external electrode side surface part 3a1 along a lateral direction of the laminate 1 is larger than the length of the second external electrode side surface part 3b1 along the lateral direction of the laminate 1.SELECTED DRAWING: Figure 1

Description

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

  In a multilayer capacitor, dielectric layers and internal electrodes are alternately laminated. As a ceramic material constituting the dielectric layer, a ferroelectric material such as barium titanate having a relatively high dielectric constant is generally used. It is used. When a DC voltage on which an AC component is superimposed is applied to such a multilayer capacitor, distortion occurs in the dielectric layer due to the electrostrictive effect due to the voltage, and the multilayer capacitor itself vibrates. The multilayer capacitor is mounted on the substrate via solder or the like. The vibration of the multilayer capacitor propagates to the substrate, and the vibration that propagates to the substrate resonates and amplifies the vibration. Occurs. 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 both end faces in the longitudinal direction of the multilayer body in order to reduce “sounding”. An example of such a multilayer capacitor is disclosed in Patent Document 1.

Japanese Patent Laid-Open No. 2015-15446

  However, the structure of the multilayer capacitor described above has a problem that the length of the external electrode along the short side direction of the multilayer body becomes small on both end faces in the longitudinal direction of the multilayer body, and the mounting stability tends to be lowered. It was.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a multilayer capacitor and a mounting structure that can suppress “sounding” and improve mounting stability. is there.

The multilayer capacitor of the present invention includes a substantially rectangular parallelepiped laminate in which a first internal electrode and a second internal electrode are laminated via a dielectric layer, and the multilayer capacitor provided on the outer surface of the laminate. A pair of external electrodes each including a first external electrode electrically connected to a first internal electrode and a second external electrode electrically connected to the second internal electrode; The stacked body includes a pair of rectangular main surfaces positioned in the stacking direction of the dielectric layer and the internal electrodes, and a pair of adjacent main surfaces positioned between the pair of main surfaces and adjacent to the long side of the main surface. And a pair of end surfaces located between the pair of main surfaces and adjacent to the short side of the main surface, and the first external electrode includes the center portion of the end surfaces. A first external electrode side surface provided on the first external electrode and the first external electrode side surface portion extending on the pair of main surfaces And a second external electrode side surface provided on the end surface so as to include a central portion of the end surface, and the second external electrode side surface portion. And a second extending portion extending on the pair of main surfaces, and the length of the side surface portion of the first external electrode along the short direction of the stacked body is the second length. The external electrode side surface portion is longer than the length along the short direction of the laminate.

  In the multilayer capacitor mounting structure of the present invention, the multilayer capacitor and the substrate are arranged such that one of the pair of main surfaces faces the mounting surface of the substrate, and the pair It is characterized by being joined via the external electrode.

  According to the multilayer capacitor of the present invention, the laminated body has a pair of external electrodes at the center of both end faces in the longitudinal direction, and the pair of external electrodes has a length along the short direction of the laminated body. Since they are provided so as to be different from each other, propagation of vibrations to the substrate can be suppressed and mounting stability can be improved.

(A) is a schematic perspective view which shows the multilayer capacitor | condenser which concerns on embodiment, (b) is sectional drawing cut | disconnected by the AA line | wire of the multilayer capacitor shown to (a), (c ) Is a cross-sectional end view taken along line BB of the multilayer capacitor shown in FIG. (A)-(c) is a top view for demonstrating an internal electrode. FIG. 2 is a plan view of the multilayer capacitor shown in FIG. 1 viewed from the main surface side. (A) And (b) is the side view which looked at the multilayer capacitor | condenser shown in FIG. 1 from the end surface side. (A) is a schematic perspective view which shows the state which mounted the multilayer capacitor | condenser shown in FIG. 1 on the board | substrate, (b) is the multilayer capacitor | condenser shown to (a) cut | disconnected by CC line | wire FIG. 2 is a cross-sectional view showing a mounting structure mounted on a substrate. (A) is a schematic perspective view showing a conventional multilayer capacitor, (b) is a plan view seen from the Z-axis direction of the coordinate axis, and (c) is a substrate of the multilayer capacitor of (b). It is sectional drawing which shows the conventional mounting structure cut | disconnected by the DD line | wire by mounting on a board | substrate on it. It is the schematic of the measuring apparatus of a sound pressure level. 6 is a graph showing a sound pressure level obtained by actually measuring the sound of the multilayer capacitor mounting structure according to the embodiment and a sound pressure level obtained by actually measuring the sound of the conventional multilayer capacitor mounted structure. (A)-(c) is the top view which planarly viewed the other example of the multilayer capacitor | condenser shown in FIG. 1 from the main surface side. 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 symmetry plane side which shows the calculation result of the vibration in 10 kHz of the conventional multilayer capacitor single-piece | unit, (b) shows the calculation result of the vibration in 10 kHz of the conventional multilayer capacitor single-piece | unit. It is the perspective view seen from the surface side. (A) is a perspective view schematically showing a vibration mode node in a conventional multilayer capacitor unit, and (b) is a state in which an external electrode is provided on the vibration mode node in (a). FIG. (A) And (b) is explanatory drawing for demonstrating the mounting structure of the multilayer capacitor | condenser which concerns on embodiment. (A)-(d) is a side view for demonstrating the other example of the external electrode shape of the multilayer capacitor | condenser shown in FIG. (A) And (b) is explanatory drawing for demonstrating typically the rising of the molten solder in the external electrode shown in FIG.14 (b) and FIG.14 (d).

<Embodiment>
Hereinafter, a multilayer capacitor 10 according to an embodiment of the present invention will be described with reference to the drawings. The multilayer capacitor 10 may have either direction upward or downward. For convenience, the multilayer capacitor 10 defines an orthogonal coordinate system XYZ, and the upper side or the lower side with the positive side in the Z direction as the upper side. The following terms shall be used. In the present embodiment, one of the pair of main surfaces (first main surface 4a and second main surface 4b) is the upper surface, and the other is the lower surface. In addition, in each drawing, the same code | symbol is used about the same member and part, and the overlapping description is abbreviate | omitted.

  FIG. 1A is a schematic perspective view showing a multilayer capacitor 10 according to an embodiment of the present invention. The multilayer capacitor 10 includes a dielectric layer 1a and internal electrodes 2 (first internal electrode 2a and A substantially rectangular parallelepiped laminated body 1 in which second internal electrodes 2b) are alternately laminated, and a pair of external electrodes provided on both end faces in the longitudinal direction of the laminated body 1 and respectively connected to different internal electrodes 2 3 (first external electrode 3a and second external electrode 3b).

  As shown in FIGS. 1 and 2, the pair of external electrodes 3 includes a first external electrode 3a and a second external electrode 3b, and the first external electrode 3a and the second external electrode 3b are laminated. The lengths along the short direction (Y direction) of the body 1 are different from each other, and in this embodiment, the length along the short direction (Y direction) of the stacked body 1 of the first external electrodes 3a. Is larger than the length along the short direction (Y direction) of the laminate 1 of the second external electrodes 3b.

  The laminated body 1 is formed by alternately laminating first internal electrodes 2a and second internal electrodes 2b via dielectric layers 1a.

  In addition, the multilayer body 1 includes a pair of rectangular main surfaces (first main surface) positioned in the stacking direction of the dielectric layer 1a and the internal electrodes 2 (first internal electrode 2a and second internal electrode 2b). 4a and second main surface 4b), a pair of side surfaces (first side surface 4e and second side surface 4f) located between the pair of main surfaces and adjacent to the long side of the main surface, and a pair of main surfaces It has a pair of end surfaces (first end surface 4c and second end surface 4d) which are located between the surfaces and are adjacent to the short side of the main surface.

  As shown in FIG. 1, the pair of external electrodes 3 includes a first external electrode side surface portion 3a1 (second external electrode side surface portion 3b1) and a first extension portion 3a2 (second extension portion 3b2). ), And the first external electrode side surface portion 3a1 (second external electrode side surface portion 3b1) includes the center portion of the first end surface 4c (second end surface 4d). Provided on the end face 4c (second end face 4d), the first extension 3a2 (second extension 3b2) extends from the first external electrode side face 3a1 (second external electrode side face 3b1). It extends on a pair of main surfaces (the first main surface 4a and the second main surface 4b) toward the central portion in the longitudinal direction (X direction) of the laminate 1. In FIG. 1, the first extending portion 3a2 and the second extending portion 3b2 are provided in a quadrangular shape. Note that the square shape includes a case where the corners are rounded.

  As described above, the first external electrode 3a is provided so that the first external electrode side surface portion 3a1 includes the central portion of the first end surface 4c and does not include both end portions, and the first extending portion 3a2 is provided. On the first main surface 4a and the second main surface 4b from the first external electrode side surface portion 3a1 toward the central portion in the longitudinal direction (X direction) of the first main surface 4a and the second main surface 4b. It is extended. The first extending portion 3a2 extends on the first main surface 4a and the second main surface 4b with the same width as the end portion (Z direction) side of the first external electrode side surface portion 3a1. Exist.

The second external electrode 3b is provided such that the second external electrode side surface portion 3b1 includes the center portion of the first end surface 4d and does not include both end portions, and the second extension portion 3b2 is the second extension portion 3b2. The external electrode side surface portion 3b1 extends on the first main surface 4a and the second main surface 4b toward the central portion in the longitudinal direction (X direction) of the first main surface 4a and the second main surface 4b. doing. Also, the second extension 3
b2 extends on the first main surface 4a and the second main surface 4b with the same width as the end portion (Z direction) side of the second external electrode side surface portion 3b1.

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

  The first external electrode 3a is provided so as to include the central portion of the first end face 4c located in the longitudinal direction (X direction) of the multilayer body 1, and is a first internal electrode drawn out to the first end face 4c. 2a is electrically connected. The second external electrode 3b is provided so as to include the central portion of the second end face 4d located in the longitudinal direction (X direction) of the multilayer body 1, and the second external electrode 3b is drawn to the second end face 4d. It is electrically connected to the internal electrode 2b.

  The central portion of the first end surface 4c is a region including a bisector that bisects the first end surface 4c vertically, and the first external electrode 3a is provided including this region. The central portion of the second end surface 4d is a region including a bisector that bisects the second end surface 4d vertically, and the second external electrode 3b is provided including this region. Yes. In FIG. 2A, the bisector 8 is indicated by a long chain line.

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

  As shown in FIG. 1, the multilayer body 1 is formed in a substantially rectangular parallelepiped shape by laminating a plurality of dielectric layers 1a and internal electrodes 2, and a pair of main surfaces (first main surface 4a) facing each other. And a second main surface 4b), a pair of end surfaces facing each other (first end surface 4c and second end surface 4d), and a pair of side surfaces facing each other (first side surface 4e and second side surface 4f). And have. A pair of end surfaces are positioned between the pair of main surfaces and orthogonal to the pair of main surfaces, a pair of side surfaces are positioned between the pair of main surfaces and orthogonal to the pair of main surfaces, and the pair of end surfaces And the pair of side surfaces are orthogonal to each other. The substantially rectangular parallelepiped shape includes not only a cubic shape or a rectangular parallelepiped shape, but also includes, for example, a chamfered ridge line portion of the rectangular parallelepiped shape and a ridge line portion having an R shape.

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

  The dimension of the multilayer capacitor 10 having such a configuration is such that the length in the longitudinal direction (Y direction) is, for example, 0.6 (mm) to 2.2 (mm), and the length in the short direction (X 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 structures of the dielectric layer 1a and the internal electrode 2 shown in FIG. 1B and FIG. 1C are schematic, and actually several to several hundred dielectric layers 1a and internal electrodes 2 are used. Are used, and the thickness per layer is, for example, 0.2 (μm) to 3 (μm). The laminated body 1 has, for example, a plurality of dielectric layers 1a composed of 10 (layers) to 1000 (layers) and internal electrodes 2 each having Z.
Laminated in the direction. Further, the number of internal electrodes 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. 2B, the first internal electrode 2a has a lead portion 2aa to the first end surface 4c at the center portion on the first end surface 4c side. As shown, it is provided between the dielectric layers 1a and is arranged such that the lead-out portion 2aa is drawn out to the first end face 4c and exposed to the first end face 4c.

  Further, as shown in FIG. 2C, the second internal electrode 2b has a lead portion 2ba to the second end surface 4d at the center portion on the second end surface 4d side, and the dielectric layer 1a. The lead-out portion 2ba is provided between the second end face 4d facing the first end face 4c and is exposed to the second end face 4d. The first internal electrode 2a and the second internal electrode 2b are not exposed on the first side surface 4e and the second side surface 4f.

  In FIG. 2A, the first internal electrode 2a exposed on the first end face 4c is indicated by a solid line, and the second internal electrode 2b exposed on the second end face 4d is indicated by a broken line. As shown in FIG. 2, the first internal electrode 2a and the second internal electrode 2b are formed so that the lengths in the longitudinal direction (Y direction) of the lead portion 2aa and the lead portion 2ba are the same. Further, the length W1 in the longitudinal direction (Y direction) of the first external electrode 3a is long, and the inductance can be reduced.

  Further, as shown in FIG. 2, the first external electrode 3a and the second external electrode 3b are formed so that the lengths in the longitudinal direction (Y direction) of the lead portion 2aa and the lead portion 2ba are the same. Yes. The lengths in the longitudinal direction (Y direction) of the lead portion 2aa and the lead portion 2ba may be different. For example, the lead portion 2aa may be formed so that the length in the longitudinal direction (Y direction) is larger than the lead portion 2ba according to the length W1 in the longitudinal direction of the first external electrode 3a. By doing so, the inductance can be reduced.

  In addition, the lead portion 2aa of the first internal electrode 2 maintains the symmetry of vibration and can reduce the number of elements that vibrate the substrate during mounting. Therefore, the first end surface of the exposed portion of the first end surface 4c is reduced. It is preferable that the bisector 8 of 4c is included, and the lead-out portion 2ba of the second internal electrode 2b is provided with an element that maintains the symmetry of vibration and vibrates the substrate during mounting. In terms of reduction, it is preferable that the bisector 8 of the second end surface 4d is included in the exposed portion of the second end surface 4d.

  The conductive material of the internal electrode 2 (the first internal electrode 2a and the second internal electrode 2b) is, for example, nickel (Ni), copper (Cu), silver (Ag), palladium (Pd), gold (Au), etc. Or an alloy material such as an Ag—Pd alloy containing at least one of these metal materials. The first internal electrode 2a and the second internal electrode 2b have an electrode thickness of, for example, 0.2 (μm) to 2 (μm), and the thickness may be set appropriately according to the application. . The first internal electrode 2a and the second internal electrode 2b are preferably formed of the same metal material or alloy material.

The first external electrode 3 a is provided at the center of the first end face 4 c located in the longitudinal direction of the multilayer body 1, and the second external electrode 3 b is a second part located in the longitudinal direction of the multilayer body 1. Is provided at the center of the end face 4d. As shown in FIG. 2B, the first external electrode 3a is formed so as to cover the lead portion 2aa of the first internal electrode 2a drawn to the first end face 4c. It is electrically connected to the electrode 2a. Further, as shown in FIG. 2C, the second external electrode 3b is formed so as to cover the lead portion 2ba of the second internal electrode 2b drawn to the second end face 4d. The internal electrode 2b is electrically connected. The first external electrode 3a and the second external electrode 3b can be formed on the first end surface 4c and the second end surface 4d by using, for example, a screen printing method or a roller transfer method.

  As shown in FIG. 1, the first external electrode 3a is provided on the first end surface 4c, and the first main surface 4a and the second main surface 4a from the first external electrode side surface portion 3a1 of the first end surface 4c. The first main surface 4b is provided so as to extend on the surface, and has a first extended portion 3a2 on the first main surface 4a and the second main surface 4b. The second external electrode 3b is provided on the second end surface 4d, and the surfaces of the first main surface 4a and the second main surface 4b from the second external electrode side surface portion 3b1 of the second end surface 4d. The second extended portion 3b2 is provided on the first main surface 4a and the second main surface 4b.

  Thus, the pair of external electrodes 3 (the first external electrode 3a and the second external electrode 3b) are formed on the surface of the laminate 1 (the first end surface 4c and the second end surface 4d) as shown in FIG. The first main surface 4a and the second main surface 4b) are formed. The pair of external electrodes 3 includes a base electrode 5 and a metal layer 6 that covers the base electrode 5.

  The pair of external electrodes 3 (first external electrode 3a and second external electrode 3b) includes a base electrode 5 and a metal layer 6, and one of the pair of base electrodes 5 from the first end face 4c. Formed to extend to first main surface 4a and second main surface 4b, and the other extends from second end surface 4d to first main surface 4a and second main 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 2a drawn to the first end face 4c, and the other is electrically connected to the second internal electrode 2b drawn to the second end face 4d. 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 4 is preferably formed on the surface of the laminate 1 with the same metal material or the same alloy material.

  Thus, the 1st external electrode 3a is comprised from the base electrode 5 and the metal layer 6, and is provided in the 1st end surface 4c from the 1st main surface 4a to the 2nd main surface 4b. The second external electrode 3b is composed of the base electrode 5 and the metal layer 6, and is provided from the first main surface 4a to the second main surface 4b on the second end surface 4d.

  As shown in FIG. 1B, 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. 1B, the metal layer 6 includes a first metal layer 6a and a second metal layer 6b, and the first metal layer 6a covers the base electrode 5. The second metal layer 6b is located outside the first metal layer 6a.

  As shown in FIG. 1B, 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 second metal layer 6b is formed of the first metal layer 6a. It is formed on the outside.

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 of the first metal layer 6a is formed so as to cover the base electrode 5, and the plating layer of the second metal layer 6b is formed of the first metal layer 6a so as to cover the plating layer of the first metal layer 6a. It is formed on the surface of the plating layer.

  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. 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). 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.

  FIG. 3 is a plan view of the multilayer capacitor 10 according to the present embodiment from the lamination direction (Z direction). In the present embodiment, when the length along the longitudinal direction (X direction) of the laminate 1 is L1, and the length along the short direction (Y direction) is L2, L1> L2. In addition, as shown in FIG. 3, in the lateral direction (Y direction) of the multilayer body 1, the end of the first extending portion 3 a 2 on the first end surface 4 c side, that is, the first external electrode side surface portion 3 a 1 side. The length of the portion (hereinafter also referred to as the outer end portion) is W1, and the end portion of the second extending portion 3b2 on the second end face 4d side, that is, the second external electrode side face portion 3b1 side (hereinafter referred to as the outer end portion). W1> W2, where W2 is also referred to as the end). In FIG. 3, the first extending portion 3a2 (second extending portion 3b2) has the same width as the end portion of the first external electrode side surface portion 3a1 (second external electrode side surface portion 3b1). It extends on the first main surface 4a and the second main surface 4b. Moreover, the corner | angular part of the 1st extension part 3a2 (2nd extension part 3b2) may be rounded.

  FIG. 4A is a side view of the multilayer capacitor 10 of the present embodiment as viewed from the first end face 4c side, and W3 is the multilayer body 1 of the first external electrode side face portion 3a1 on the first end face 4c. It is the length along the short direction (Y direction). Similarly, FIG. 4B is a side view of the multilayer capacitor 10 of the present embodiment as viewed from the second end face 4d side, and W4 is a second external electrode side face portion on the second end face 4d. It is the length along the short side direction (Y direction) of the laminate 1 of 3b1. The maximum length at the first end face 4c is the length W3 in the short direction (Y direction) of the laminate 1 of the first external electrode side face 3a1, and the maximum length at the second end face 4d is The length W4 in the short direction (Y direction) of the multilayer body 1 of the second external electrode side surface portion 3b1 is set.

  As shown in FIG. 4, H0 is the height of the multilayer capacitor 10 in the stacking direction of the multilayer body 1, and H1 is the first external electrode side surface on the first end surface 4c (second end surface 4d) side. This is the length along the stacking direction of the portion 3a1 (second external electrode side surface portion 3b1). In the present embodiment, H1 = H0, and the first external electrode side surface portion 3a1 (second external electrode side surface portion 3b1) extends from the upper side to the lower side in the first end surface 4c (second end surface 4d). Is provided.

  As shown in FIG. 4, the pair of external electrodes 3 includes a length W3 of the first external electrode side surface portion 3a1 along the short direction of the multilayer body 1 and a first length along the short direction of the multilayer body 1. The length W4 of the second external electrode side surface portion 3b1 is provided such that W3> W4. In particular, in the multilayer capacitor 10, the first external electrode side surface portion 3a1 has a length W3 along the short direction of the multilayer body 1 that is 0.4 times the length L2 along the short direction of the multilayer body 1. And the second external electrode side surface portion 3b1 has a length W4 along the short direction of the multilayer body 1 of 0. 2 of the length L2 along the longitudinal direction of the multilayer body 1. It is preferable to be provided so as to be smaller than four times.

Thus, the length W3 of the first external electrode side surface portion 3a1 is larger than 0.4 as a ratio (W3 / L2) to L2 from the viewpoint of mounting reliability, and further, from 0.5 In addition, the length W4 of the second external electrode side surface portion 3b1 is 0.4 in terms of the ratio (W4 / L2) to L2 from the viewpoint of reducing vibration of the substrate when mounted on the substrate. It is preferable that it is smaller than 0.35 and further smaller than 0.35. Further, the length W3 of the first external electrode side surface portion 3a1 and the length W4 of the second external electrode side surface portion 3b1 are in a relationship of W3: W4 = 1: 0.2 to 0.5. It is more preferable from the viewpoint of suppression of noise and mounting stability.

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

  5A shows a state in which the multilayer capacitor 10 is mounted on the substrate 9, and FIG. 5B 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 -C 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.

  Further, as shown in FIG. 5, the substrate 9 is provided with a substrate electrode 9a and a substrate electrode 9b on the surface on which the multilayer capacitor 10 is mounted, and wiring (not shown) is provided from the substrate electrode 9a. Further, a 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. . In the soldered multilayer capacitor 10, one of the first main surface 4 a and the second main surface 4 b faces the mounting surface of the substrate 9.

  As shown in FIG. 5, the mounting structure of the multilayer capacitor 10 of the present embodiment has the first external electrode 3a and the substrate electrode 9a joined together via a conductive material such as solder. The external electrode 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 present embodiment, the multilayer capacitor 10 is arranged such that the first main 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 first external electrode side surface portion 3a1 and the second external electrode A solder fillet layer 7 is formed along side surface portion 3b1. As shown in FIG. 5B, C is the distance between the mounting surface of the substrate 9 and the multilayer capacitor 10, and H2 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. 6A, the conventional multilayer capacitor 100 includes a substantially rectangular parallelepiped multilayer body 101 and external electrodes 103 provided on the outer surfaces of both ends thereof. FIG. 6B is a plan view seen from the z-axis direction of FIG. FIG. 6C is a cross-sectional view taken along the line DD of FIG. 6B and shows a conventional mounting structure of the multilayer capacitor 100 mounted on the substrate 90.

  As shown in FIG. 6C, the laminated body 101 is obtained by alternately laminating dielectric layers 101a and internal electrodes. The internal electrode 102 is electrically connected to the external electrode 103 at one of both end portions of the multilayer body 101. In the multilayer capacitor 100, the dielectric layer 101a, the internal electrode 102, and the external electrode 103 are made of the same material as that of the multilayer capacitor 10 of this embodiment.

  As shown in FIG. 6C, the conventional multilayer capacitor 100 is fixed in a state where the external electrode 103 and the substrate electrodes 90a and 90b on the substrate 90 are electrically connected via solder. . The solder fills the gap between the external electrode 103 and the substrate electrodes 90a and 90b, and further covers the end surface of the laminate 101 and the external electrode 103 that covers 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. Further, when the piezoelectric vibration of the multilayer capacitor 100 is transmitted to the substrate 90 through the solder fillet layer 70 and the substrate 90 vibrates, and the substrate 90 resonates at an audible resonance frequency, a vibration sound called “sounding” is generated. Occur.

  The sound produced when the multilayer capacitor 10 of the present embodiment was mounted on the substrate 9 and the sound produced when the conventional multilayer capacitor 100 was mounted on the substrate 90 were measured. For the measurement, a 1005 type multilayer capacitor (capacitance 10 μF, rated voltage 4 V) was used. As the multilayer capacitor 10, a capacitor having an outer dimension of 1100 × 620 × 620 (μm), W3 of 290 (μm), W4 of 170 (μm), and P1 (P2) of 165 (μm) was used. In addition, as the conventional multilayer capacitor 100, one having an outer dimension of 1100 × 620 × 620 (μm) was used. As the substrate 9 (substrate 90), a glass epoxy substrate made of FR4 (Flame retardant Type 4) material having a size of 100 × 40 mm and a thickness of 0.8 mm was used. The multilayer capacitor 10 and the multilayer capacitor 100 were mounted on the center of the substrate 9 (substrate 90) using Sn-Ag-Cu (SAC) solder. After mounting on the substrate 9 (substrate 90), the mounting state is observed with a microscope, the height of the solder fillet layer 7 (solder fillet layer 70) is 460 (μm), the substrate 9 (substrate 90) and the multilayer capacitor It was confirmed that the distance C to 10 (multilayer capacitor 100) was 45 (μm).

  The measurement was performed using a sound pressure level measuring apparatus as shown in FIG. A mounting substrate 21 (hereinafter also simply referred to as a mounting substrate) in which the multilayer capacitor 10 (multilayer capacitor 100) is mounted on a substrate 9 (substrate 90) is placed in an anechoic box 22 (inner dimensions 600 × 700 mm, height 600 mm). The sound collecting microphone 23 was installed at a position 3 mm away from the center of the substrate 9 (substrate 90) in a direction perpendicular to the substrate 9 (substrate 90). The sound collected by the sound collecting microphone 23 was collected, and the sound pressure level of the collected sound was measured by the amplifier 24 and the FET analyzer 25 (DS2100 manufactured by Ono Sokki). Measurement was performed by applying a DC voltage (DC bias) of 4 V and an AC voltage of 20 V to 20 kHz and 4 Vp-p to the multilayer capacitor 10 (multilayer capacitor 100). The measurement result of the squeal is shown in FIG. The result of the multilayer capacitor 10 is indicated by A, and the result of the multilayer capacitor 100 is indicated by B.

  In FIG. 8, the sound pressure level is indicated by an A characteristic sound pressure level (dBA). A characteristic sound pressure level of 0 dBA corresponds to the lowest sound pressure level that humans can hear as sound. The A characteristic sound pressure level is a sound pressure level weighted for each frequency so as to be close to human hearing, and is described in a standard of a sound level meter (sound level meter) (JISC1509-1: 2005).

When the obtained results are averaged over the frequency range of 4 Hz to 20 kHz, the average value of the sound pressure level in the multilayer capacitor 10 of this embodiment is reduced by about 4 dBA with respect to the conventional mounting structure of the multilayer capacitor 100. It became. The first external electrode side surface portion 3a1 is formed so as to include the node-like portion 15, and the length W3 along the short direction of the multilayer body 1 is larger than 0.4 times L2. Thus, the multilayer capacitor 10 can be stably mounted on the substrate 9. Therefore, the multilayer capacitor 1
0 can suppress “sounding” and improve mounting stability and mounting reliability. Further, the first external electrode side surface portion 3a1 has a length W3 along the short direction of the multilayer body 1 larger than 0.5 times L2, that is, larger than half of the length of the multilayer body 1. If so provided, the “sounding” can be suppressed and the multilayer capacitor 10 can be more stably mounted on the substrate 9.

  For example, when the length W3 of the first external electrode side surface portion 3a1 and the length W4 of the second external electrode side surface portion 3b1 are smaller than 0.4 times the length L2 along the lateral direction of the laminate 1 At the time of reflow for performing solder joint, the multilayer capacitor is lifted by the surface tension of the molten solder, and the solder in a state where one end portion in the short direction of the multilayer body 1 is inclined toward the substrate 9 and is in contact with the substrate. There is a risk of joining. As described above, when the multilayer capacitor and the substrate 9 are soldered and joined, the vibration of the multilayer capacitor is directly transmitted to the substrate 9 and the effect of suppressing “sounding” is likely to be reduced.

  However, the multilayer capacitor 10 floats due to the surface tension of the molten solder during reflow for solder joining, but the length W3 of the first external electrode side surface portion 3a1 is 0.4, which is the length L2 of the multilayer body 1. Since it is provided so as to be larger than twice, it is possible to balance the horizontal direction and to easily mount the multilayer capacitor 10 on the substrate 9. That is, by providing the length W3 of the first external electrode side surface portion 3a1 to be larger than 0.4 times the length L2 of the multilayer body 1, the end portion in the short direction of the multilayer capacitor 10 is formed on the substrate. The multilayer capacitor 10 is bonded to the substrate electrodes 9a and 9b in a state corresponding to a so-called three-point support state, so that mounting stability is improved. Therefore, the multilayer capacitor 10 is less likely to contact the substrate at the end in the short direction, and the vibration of the multilayer capacitor 10 is not directly transmitted to the substrate 9. Further, by providing the length W3 of the first external electrode side surface portion 3a1 to be longer than half of the length L2 of the multilayer body 1, it is possible to suppress “sounding” and further improve the mounting stability. Is more preferable.

  Further, for example, the length W3 of the first external electrode side surface portion 3a1 and the length W4 of the second external electrode side surface portion 3b1 are larger than 0.4 times the length L2 along the lateral direction of the multilayer body 1. If it is small, the joining state of the joint portion between the first external electrode 3a and the substrate electrode tends to be unstable, and the joining state of the joint portion between the second external electrode 3b and the substrate electrode becomes unstable. There is a possibility that the multilayer capacitor is inclined with respect to the substrate, that is, one end of both ends of the multilayer capacitor in the short direction is inclined and bonded to the substrate 9 side. In such a bonded state, for example, when the substrate 9 warps due to the influence of temperature or the like, the substrate easily comes into contact with the short-side end portion of the multilayer capacitor, and the vibration of the multilayer capacitor directly causes the substrate 9 to vibrate. The effect of suppressing “sounding” tends to decrease.

  However, since the multilayer capacitor 10 is provided such that the length W3 of the first external electrode side surface portion 3a1 is larger than 0.4 times the length L2 of the multilayer body 1, the horizontal balance is improved. It is easy to be mounted horizontally with respect to the substrate 9. Even when the substrate 9 is warped due to the influence of temperature or the like, the substrate 9 is unlikely to contact the end of the multilayer capacitor 10 in the longitudinal direction. Therefore, in the multilayer capacitor 10, it is difficult for the substrate 9 to come into contact with the end portion in the short direction, and the vibration of the multilayer capacitor 10 is not easily transmitted to the substrate 9. Further, by providing the length W3 of the first external electrode side surface portion 3a1 so as to be larger than half of the length L2 of the multilayer body 1, the “sounding” is suppressed and the mounting stability is further improved. Is more preferable.

  Further, for example, the length W3 of the first external electrode side surface portion 3a1 and the length W4 of the second external electrode side surface portion 3b1 are larger than 0.4 times the length L2 along the lateral direction of the multilayer body 1. If it is large, the mounting stability and mounting reliability are improved, but the effect of suppressing “sounding” tends to decrease.

  Here, FIG. 11 shows a calculation result obtained by calculating the vibration mode in the audible frequency region (20 Hz to 20 kHz) of the multilayer capacitor 100 at 10 kHz using the 1/8 model (FIG. 10). In addition, as shown in FIG. 10, the 1/8 model considers symmetry, and two cross sections appearing on the front surface of FIG. 10 and a lower cross section are symmetrical planes. 11A is a view from the inside (symmetry plane side) of the 1/8 model, and FIG. 11B is the opposite side of FIG. 11A, that is, the outside of the 1/8 model. Viewed from the side (surface side). Here, the broken line indicates the shape of the evaluation component in a state where no AC voltage is applied, and the solid line indicates the shape of the evaluation component that is displaced to the maximum by the AC voltage.

  From this result, it can be seen that in the audible frequency region, the evaluation component performs spreading vibration in the stacking surface direction and stretching vibration in the stacking direction (thickness direction). As schematically shown in FIG. 12 showing the entire evaluation component, in the pair of main surfaces (first main surface 4a and second main surface 4b) facing each other in the stacking direction of the evaluation components, It can be seen that there is a region having a small vibration amplitude, that is, a node of vibration (hereinafter referred to as a node-like portion 15) at the center of each side constituting the surface.

  Since the multilayer capacitor 10 of the present embodiment is equivalent to the multilayer capacitor 100, such a node 15 is formed at the center of each side of the multilayer capacitor 10 of the present embodiment, like the multilayer capacitor 100. Is also present. Therefore, by fixing the multilayer capacitor 10 to the substrate 9 through the pair of external electrodes 3 and solder at the node portion 15, the propagation of piezoelectric vibration of the multilayer capacitor 10 to the substrate 9 is suppressed, and the sound is emitted. Can be reduced.

  In the present embodiment, as shown in FIG. 12B, the multilayer capacitor 10 includes the above-described node-like portion 15, and the first external electrode 3 a and the second electrode 15 are formed on the node-like portion 15. Since the external electrode 3b is provided, the multilayer capacitor 10 can be fixed to the substrate 9 at the node 15.

  Therefore, the first external electrode side surface portion 3 a 1 is formed from the first main surface 4 a or the second main surface 4 b to the first end surface 4 c so as to include the node-shaped portion 15. Similarly, the second external electrode side surface portion 3 b 1 is formed from the first main surface 4 a or the second main surface 4 b to the second end surface 4 d so as to include the node-shaped portion 15.

  In this embodiment, W4 (170 μm) is set to 0.27 as a ratio (W4 / L2) to L2 (620 μm). However, even if this is set to 0.35, the sound pressure level can be reduced as compared with the conventional case. it can. W3 / L2 is preferably larger than 0.4 from the viewpoint of mountability, and more preferably larger than 0.5.

  W3, which is the length in the short direction (Y direction) of the laminate 1 of the first external electrode side surface portion 3a1 at the first end face 4c, is 0.4 to 0 as a ratio (W3 / L2) to L2. .85 is preferable. From the result of FIG. 11, the region having a relatively small vibration amplitude including the node-like portion 15 is centered on the center (bisector) on the short side of the first main surface 4a (second main surface 4b). In the case of the multilayer capacitor 100 or over the entire short side, the first external electrode 3a is provided in the range of about 0.85 of the short side length. Compared with the case where the electrode 3a is provided, a noise reduction effect can be obtained. In the above description, W3 / L2 is set to 0.47. However, even if this is set to 0.85, a noise reduction effect can be obtained as compared with the evaluation part. In view of mounting stability, W3 / L2 is preferably 0.4 or more. W3 / L2 is particularly preferably in the range of 0.4 to 0.7 from the viewpoint of reducing vibration and ensuring mounting stability.

  In addition, W4, which is the length in the short direction (Y direction) of the stacked body 1 of the second external electrode side surface portion 3b1 at the second end face 4d, is 0.2 (W4 / L2) as a ratio to L2. It is preferable to set it to -0.4. From the result of FIG. 14, the region including the node-like portion 15 and having a relatively small vibration amplitude is centered on the center (bisector) of the short side of the first main surface 4a (second main surface 4b). In the case of the multilayer capacitor 100 or the entire short side, the second external electrode 3b is provided in the range of about 0.85 of the short side length. Compared with the case where the electrode 3b is provided, a noise reduction effect can be obtained. In the above description, W4 / L2 is set to 0.27, but even if this is set to 0.4, a sound reduction effect can be obtained. In view of mounting stability, W4 / L2 is preferably 0.2 or more. W4 / L2 is particularly preferably in the range of 0.3 to 0.4 from the viewpoint of reducing vibration and ensuring mounting stability.

  In the mounting structure of the present embodiment, the multilayer capacitor 10 is not in direct contact with the mounting surface of the substrate 9. In particular, the ratio (C / H0) of C to H0, which is the distance between the multilayer capacitor 10 and the mounting surface of the substrate 9, is preferably 0.03 or more. In the above description, C / H0 is set to 0.07.

  Furthermore, according to the result of the vibration mode analysis as described above, the vibration amplitude is large in the vicinity of the center of each surface constituting the laminate 1. Therefore, in the first main surface 4a, the length P1 of the first extending portion 3a2 in the longitudinal direction of the stacked body 1 is preferably 0.25 or less in terms of the ratio (P1 / L1) to L1. The length P2 of the second extending portion 3b2 is preferably 0.25 or less in terms of the ratio (P2 / L1) to L1. In this embodiment, it is set to 0.15. However, by setting P1 (P2) / L1 to 0.25 or less, the vibration at the center of the first main surface 4a (second main surface 4b) having a large vibration amplitude. Is difficult to be transmitted to the substrate 9, and the sound is suppressed. Further, from the viewpoint of ensuring mounting stability, P1 (P2) / L1 is preferably set to 0.15 or more. Further, P1 and P2 may be the same length or different lengths.

  FIG. 9 is a plan view of the multilayer capacitor 10 of the present embodiment from the lamination direction (Z direction). As shown in FIG. 9, the first extending portion 3 a 2 and the second extending portion 3 b 2 have a length along the short direction of the laminate 1 that is greater on the side of the external electrode than on the central side of the main surface. You may provide so that it may become. Specifically, in the short-side direction (Y direction) of the multilayer body 1, the end portion of the first extending portion 3 a 2 on the first end surface 4 c side, that is, the first external electrode side surface portion 3 a 1 side (hereinafter, The length of the first main surface 4a (second main surface 4b) in the longitudinal direction (X direction) (hereinafter also referred to as the inner end portion) is W1. When the length is W1a, W1> W1a. Similarly, in the short side direction (Y direction) of the multilayer body 1, the end portion on the second end surface 4 d side of the second extending portion 3 b 2, that is, the end portion on the second external electrode side surface portion 3 b 1 side (hereinafter, The length of the first main surface 4a (second main surface 4b) in the longitudinal direction (X direction) (hereinafter also referred to as the inner end portion) is W2. When the length is W2a, W2> W2a.

  In other words, the length of the first extending portion 3a2 along the short direction (Y direction) of the multilayer body 1 is the end of the first extending portion 3a2 on the first external electrode side surface portion 3a1 side. It has a shape that becomes smaller toward the center side with the portion (outer end portion) as the maximum. The length of the second extending portion 3b2 along the short direction (Y direction) of the multilayer body 1 is the end of the second extending portion 3b2 on the second external electrode side surface portion 3b1 side ( It has a shape that becomes smaller toward the center with the outer end portion being maximized.

Specifically, the first external electrode side surface portion 3a1 (second external electrode side surface portion 3b1) side, that is, a base having the first main surface 4a (second main surface 4b) as a base (lower base). Shape (FIG. 9 (a)), triangle shape (FIG. 9 (b)), arcuate shape (semicircular shape, semicircular shape) with the first external electrode side surface portion 3a1 (second external electrode side surface portion 3b1) side as a string (Including an elliptical shape) (FIG. 9C). In the case of a polygonal shape such as a triangular shape or a trapezoidal shape, the case where the corner (vertex) is rounded is included. Further, the inner end of the first extending portion 3a2 (second extending portion 3b2) is recessed toward the first outer electrode side surface portion 3a1 ((second outer electrode side surface portion 3b1) side. In addition, the shape of the first extension portion 3a2 and the second extension portion 3b2 is triangular or arcuate as shown in Fig. 9 (b) or Fig. 9 (c). None, when it is difficult to evaluate the length of the inner end portion in the Y direction, the outer end portion corresponds to the length P1 (P2) in the X direction of the first extension portion 3a2 (extension portion 3b). The position 0.9 times as large as P1 (P2) may be evaluated as the inner end portion.

  Further, the first extending portion 3a2 formed on the first main surface 4a (second main surface 4b) has a length W1 of an end portion (outer end portion) on the first end surface 4c side, The first main surface 4a (second main surface 4b) is provided so as to be larger than the length W1a of the end portion (inner end portion) on the center side in the longitudinal direction (X direction) (W1> W1a). Yes. Further, the second extending portion 3b2 formed on the first main surface 4a (second main surface 4b) has a length W2 of an end portion (outer end portion) on the first end surface 4c side, The first main surface 4a (second main surface 4b) is provided so as to be larger than the length W2a of the end portion (inner end portion) on the center side in the longitudinal direction (X direction) (W2> W2a). .

  The first external electrode 3a is provided from the first main surface 4a or the second main surface 4b to the second end surface 4c so as to be located inside the node-shaped portion 15, and the second external electrode 3a The electrode 3b may be provided from the first main surface 4a or the second main surface 4b to the second end surface 4d so as to be located inside the node-like portion 15.

  Thus, the length of the first extending portion 3a2 (second extending portion 3b2) is set to the length of the outer end portion, that is, the length on the node-like portion 15 side, W1 (W2). The first extending portion 3a2 is reduced by reducing W1a (W2a), which is the length of the inner end portion, that is, the center portion side of the first main surface 4a (second main surface 4b) having a large vibration amplitude. In the (second extending portion 3b2), the region located on the center side of the first main surface 4a (second main surface 4b) having a large vibration amplitude is reduced, and the vibration of the multilayer capacitor 10 is applied to the substrate 9. As compared with the case of W1 (W2) ≦ W1a (W2a), the effect of suppressing “sounding” is obtained.

  Further, the multilayer capacitor 10 includes the first external electrode 3a and the second external electrode that are rectangular in any of the first main surface 4a, the second main surface 4b, the first end surface 4c, and the second end surface 4d. For example, the first extending portion 3a2 (second extending portion 3b2) has a trapezoidal shape and has a large vibration amplitude compared to the multilayer capacitor having the outer electrode 3b. The first extending portion 3a2 (second extending portion 3b2) region located on the center side of the main surface 4b) of the second main surface 4b) is reduced, and has an effect of reducing the average value of the sound pressure level. .

  Further, the first extending portion 3a2 (second extending portion 3b2) has an outer end length W1 (W2) and an inner end length W1a (W2a), and W1 (W2): W1a A relationship of (W2a) = 1: 0.2 to 0.5 is more preferable in terms of suppression of noise and mounting stability.

  The shape of the first extending portion 3a2 (second extending portion 3b2) is an isosceles triangular shape, an isosceles trapezoidal shape, and an arc shape considering the shape of the node-like portion 15 from the result of FIG. Is preferable, and an arcuate shape is particularly preferable. When the first extension portion 3a2 (second extension portion 3b2) has a shape such as a triangle, the extension portion 3a1 (second extension portion 3b2) is stacked starting from the corner portion. There is a concern that the solder joining the substrate 9 and the first external electrode 3a (second external electrode 3b) may be cracked when peeled from the body 1 or mounted on the substrate 9. The extension part 3a1 (second extension part 3b2) has a curved (bow-like) corner having an R (radius of curvature) so that the extension part 3a1 (second extension part 3b2) does not easily peel from the laminate 1 and cracks in the solder. Is less likely to occur, and the mounting reliability can be improved. Also, in the case of a polygonal shape such as a triangular shape or a trapezoidal shape, the extending portion 3a1 (second extending portion 3b2) is formed in the laminated body 1 by making the corner portion (vertex) round. It is difficult to peel off from the solder, cracks in the solder hardly occur, and the mounting reliability can be improved.

  In the present embodiment, for example, in the case of the multilayer ceramic capacitor 10 using a ferroelectric material such as barium titanate as a dielectric layer and using a metal material such as Ni, Cu, Ag, Ag-Pd as an internal electrode. And particularly preferably used. The present embodiment can exert a remarkable effect particularly in the multilayer capacitor 10 of the 1005 type or more type.

  Furthermore, as the external electrode 3, for example, in many multilayer capacitors, a base electrode made of Cu and subjected to Ni and Sn plating is used as the external electrode, but only the plated electrode is used without using the base electrode. It can be used suitably also for what has the comprised external electrode 3. FIG. When the external electrode 3 having the base electrode is directly joined to the substrate electrodes (9a, 9b) of the substrate 9 via solder or the like, the base electrode made of Cu is relatively soft, so that the base electrode causes piezoelectric vibration of the laminate 1. It absorbs and attenuates to some extent, and the noise is suppressed. On the other hand, when the external electrode 3 is composed only of a plating electrode, the piezoelectric vibration of the laminated body 1 is not attenuated by the external electrode 3 and the squeal becomes remarkable. Therefore, when this embodiment is applied to an electrode having an external electrode composed only of a plating electrode, a larger noise reduction effect can be obtained.

  In the multilayer capacitor 10, one of the first external electrode 3a and the second external electrode 3b is electrically connected to a power supply line on the substrate, and the other is electrically connected to a ground line on the substrate. Furthermore, the ground line is often connected to a ground electrode having a large area on the substrate, and the ground line and the ground electrode tend to have a large heat capacity. For example, as shown in FIG. 13, the first external electrode 3a is connected to the substrate electrode 9a electrically connected to the power supply line, and the second external electrode 3b is electrically connected to the ground line. It is connected to the substrate electrode 9b. The substrate electrode 9 a is electrically connected to the power supply line, and the substrate electrode 9 b is electrically connected to the ground electrode 11 through the via conductor layer 12. The power supply line is electrically connected to the semiconductor element 13 via the bump 14.

  For example, when the lengths W3 and W4 (electrode widths) of the electrodes along the short direction of the stacked body of the first external electrode side surface portion 3a1 and the second external electrode side surface portion 3b1 are the same and the length When the solder is reflowed, the balance of melting of the solder tends to be lost in the first external electrode 3a and the second external electrode 3b due to the heat capacity of the ground line. That is, when the reflow condition is set based on the grounding line, the grounding line side has a large heat capacity, so the temperature does not easily rise, the solder melting time is short, and the solder joint becomes insufficient. On the other hand, on the power supply line side, the temperature is likely to rise, and the solder joint is excessively advanced, so that the joint portion tends to become brittle. Therefore, when an electrode having a large heat capacity is provided on the power supply line side and an electrode having a small heat capacity is provided on the ground line side, the balance of the heat capacity is uniformed, solder jointability becomes uniform, and joint reliability is improved.

  In the multilayer capacitor 10 of this embodiment, the first external electrode side surface portion 3a1 and the second external electrode side surface portion 3b1 are different from each other in electrode lengths W3 and W4. For example, the first external electrode side surface portion 3b1 The length W3 of the portion 3a1 is larger than 0.4 times the length along the longitudinal direction of the multilayer body 1, and the length W4 of the second external electrode side surface portion 3b1 is along the longitudinal direction of the multilayer body 1. It is smaller than 0.4 times the length. Therefore, in the multilayer capacitor 10, the first external electrode 3a is joined to the power supply line side, and the second external electrode 3b is joined to the ground line side, so that the solderability becomes uniform and the joint reliability is improved. Improves. In other words, the multilayer capacitor 10 has a uniform solder joint by making the electrode length W3 of the first external electrode side surface portion 3a1 different from the electrode length W4 of the second external electrode side surface portion 3b1. Thus, the joining reliability can be improved.

In addition, the second external electrode 3b is electrically connected to the ground line and the ground electrode. In the first external electrode 3a having a large electrode width, the length of the lead portion 2aa in the longitudinal direction (Y direction) is The lead-out portion 2 is increased by increasing the length of the side surface portion 3a1 of the external electrode 1 according to the length W3.
The cross-sectional area of aa becomes large and the inductance can be reduced.

  The multilayer capacitor 10 has a shape on the first end face 4c (second end face 4d) of the first external electrode 3a (second external electrode 3b), that is, the first external electrode side face 3a1 (second The shape of the external electrode side surface portion 3b1) is not limited to a rectangular shape. The length W3 (W4) in the short side direction (Y direction) of the laminate 1 of the first external electrode side surface portion 3a1 (second external electrode side surface portion 3b1) is the first end surface 4c (second end surface 4d). ), The width of the electrode positioned at the center of the stack 1 in the stacking direction (Z direction) is smaller than the width of the electrodes positioned at both ends, that is, the first external electrode side surface 3a1 (second external electrode) The side surface portion 3b1) may have a region where the width of the electrode becomes narrow at the center portion in the stacking direction (Z direction) of the first end surface 4c (second end surface 4d).

  Below, the shape of 1st external electrode side part 3A1-3A4 is demonstrated. Note that the same effect can be obtained when the shapes of the first external electrode side surface portions 3A1 to 3A4 are applied to the second external electrode 3b. In addition, the multilayer capacitor 10 shown in FIG. 14 includes the lengths of the first external electrode side surface portions 3A1 to 3A4 (second external electrode side surface portions 3B1 to 3B4) along the short direction (Y direction) of the multilayer body 1. Are different between the central part in the stacking direction (Z direction) and both end parts (first main surface 4a and second main surface 4b side), and has a region with a narrow electrode width in the central part. . In such a case, the maximum length of the first end surface 4c (second end surface 4d) is set to be the same as that of the first external electrode side surface portions 3A1 to 3A4 (second external electrode side surface portions 3B1 to 3B4). A length W3 in the short direction (Y direction) of the laminate 1 is set.

  Since the first external electrode side surface portions 3A1 to 3A4 have a region with a narrow electrode width in the stacking direction (Z direction) of the multilayer body 1, the solder creeping is suppressed in the region with the narrow electrode width, and the vibration amplitude The solder fillet layer 7 is less likely to be formed at the central portion of the first end face 4c having a large height, and the vibration of the multilayer capacitor 10 is less likely to be transmitted to the substrate 9. Further, on both end sides (first main surface 4a side and second main surface 4b side) in the stacking direction (Z direction) of the stacked body 1, the electrode width is larger than the center portion, and the substrate 9 In addition to ensuring the bonding strength with the substrate electrodes 9a and 9b, the effect of suppressing "sounding" can be improved.

  As shown in FIG. 14A, the first external electrode side surface portion 3A1 has a shape in which a rectangular central portion is cut out, and has a concave portion in the central portion of both sides of the rectangular shape. That is, the first external electrode 3a has a shape having a recess at the center of both side portions of the first external electrode side surface portion 3A1. Here, the concave portions are the first external electrodes when a pair of line segments that are located at both ends in the Y direction at the upper and lower ends of the first external electrode side surface portion 3A1 and connect vertices facing each other in the Z direction are drawn. The contour of the electrode side surface portion 3A1 is a portion located between a pair of line segments.

  As shown in FIG. 14B, the first external electrode side surface portion 3A2 has a shape in which a rectangular central portion is cut out, and both the corner portions 17 located inside the cut-out region have both. Has roundness.

  As shown in FIG. 15A, the first external electrode side surface portion 3A2 has both rounded corner portions 17 located inside the cut-out region. For example, the first external electrode side surface portion 3A2 is reflow soldering. At this time, the molten solder 16 crawls up along the rounded portion of the region sandwiched between the corners 17 positioned below in the Z direction, and the molten solder 16 tends to be circular, increasing the surface tension effect. To do. The first external electrode side surface portion 3A2 has a region with a narrow electrode width at the center, and the molten solder 16 is difficult to wet in a region with a narrow electrode width at the center due to the surface tension of the molten solder 16, and the molten solder 16 Crawling up is suppressed. Therefore, in the multilayer capacitor 10, the solder fillet layer 7 is difficult to be formed at the central portion of the first end face 4 c having a large vibration amplitude or above the central portion, and vibration is hardly transmitted to the substrate 9.

  Further, as shown in FIG. 14C, the first external electrode side surface portion 3A3 has a shape in which a central portion of a rectangular shape is cut out, and further, the corner portion 17 positioned inside the cut-out region. Both have roundness, and both corners located outside the clipped area have roundness. The first external electrode side surface portion 3A3 has the same effect as the first external electrode side surface portion 3A2.

  Further, as shown in FIG. 14D, the first external electrode side surface portion 3A4 has an electrode width from the central portion toward both end portions (the first main surface 4a side and the second main surface 4b side). It is getting bigger gradually. That is, both sides of the first external electrode side surface portion 3A4 are curved inward, have a region with a narrow electrode width at the center of the first end surface 4c, and the electrode width is vertical from the center. It gradually becomes larger toward.

  As shown in FIG. 15 (b), the first external electrode side surface portion 3A4 has curved portions 18 (roundness) that are recessed inward on both side portions. For example, during reflow for soldering, The molten solder 16 crawls up along the curved portion 18 in the region sandwiched between the curved portions 18 below the curved portion 18, and the molten solder 16 tends to be circular, and the surface tension effect is increased. The external electrode side surface portion 3A4 has a narrow electrode width region at the center of the first end surface 4c, and the molten solder 16 is difficult to wet in the narrow region of the electrode width due to the surface tension of the molten solder 16, The creeping of the molten solder 16 is suppressed. Therefore, in the multilayer capacitor 10, the solder fillet layer 7 is hardly formed on the central portion of the first end face 4 c) having a large vibration amplitude or above the central portion, and vibration is not easily transmitted to the substrate 9. Further, the shape of the bending portion 18 is appropriately set according to the amount of the molten solder 16 and the like.

  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, a 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 2a 1st internal electrode 2aa Extraction part 2b 2nd internal electrode 2ba Extraction part 3 External electrode 3a 1st external electrode 3a1, 3A1, 3A2, 3A3, 3A4 1st exterior Electrode side surface portion 3a2 First extending portion 3b Second external electrode 3b1 Second external electrode side surface portion 3b2 Second extending portion 4a First main surface 4b Second main surface 4c First end surface 4d First 2 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, 100 Multilayer capacitor 15 Node-shaped portion 16 Molten solder 17 Corner portion 18 Curved portion

Claims (8)

A substantially rectangular parallelepiped laminate in which a first internal electrode and a second internal electrode are laminated via a dielectric layer;
From the first external electrode electrically connected to the first internal electrode and the second external electrode electrically connected to the second internal electrode provided on the outer surface of the laminate And a pair of external electrodes
The stacked body includes a pair of rectangular main surfaces positioned in the stacking direction of the dielectric layer and the internal electrode, and a pair of adjacent main surfaces positioned between the pair of main surfaces and adjacent to the long side of the main surface. And a pair of end faces located between the pair of principal surfaces and adjacent to the short side of the principal surface,
The first external electrode extends on the pair of main surfaces from a first external electrode side surface portion provided on the end surface so as to include a central portion of the end surface and the first external electrode side surface portion. A first extension part,
The second external electrode extends on the pair of main surfaces from a second external electrode side surface provided on the end surface so as to include a central portion of the end surface and the second external electrode side surface portion. A second extension part,
The length of the side surface portion of the first external electrode along the short direction of the multilayer body is larger than the length of the side surface portion of the second external electrode along the short direction of the multilayer body. Multilayer capacitor to be used.   The length of the first extending portion along the short direction of the stacked body is larger than the length of the second extending portion along the short direction of the stacked body. Item 2. The multilayer capacitor according to Item 1.   3. The laminated structure according to claim 1, wherein the first extension part and the second extension part have an arcuate shape having a chord on the short side of the main surface. 4. Type capacitor.   3. The stacked structure according to claim 1, wherein shapes of the first extension portion and the second extension portion are trapezoids having a short side of the main surface as a bottom side. 4. Type capacitor.   3. The stacked structure according to claim 1, wherein shapes of the first extending portion and the second extending portion are triangular shapes having a short side of the main surface as a bottom side. 4. Type capacitor.   The length of the side surface portion of the first external electrode along the short direction of the multilayer body is greater than 0.4 times the length along the short direction of the multilayer body, and the second external electrode 6. The length of the side part along the short direction of the laminate is less than 0.4 times the length along the transverse direction of the laminate. The multilayer capacitor according to any one of the above. The length of the side surface portion of the first external electrode or the side surface portion of the second external electrode along the short direction of the stacked body is such that the end side in the stacking direction is larger than the center side. The multilayer capacitor according to claim 1. The multilayer capacitor according to any one of claims 1 to 7 and the substrate are arranged so that one of the pair of main surfaces and a mounting surface of the substrate face each other, and the pair of capacitors A mounting structure characterized by being bonded via an external electrode.

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