JP2015084435A - Laminate ceramic electronic part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminate ceramic electronic part which makes possible to prevent a plating layer from being damaged owing to the electrolytic concentration.SOLUTION: A laminate ceramic capacitor 10 that is a laminate ceramic electronic part comprises a ceramic elemental body 12. The ceramic elemental body 12 has internal electrodes 16a and 16b embedded therein. On the sides of end faces of the ceramic elemental body 12, external electrodes 20a and 20b which are electrically connected with exposed portions of the internal electrodes 16a and 16b are formed. As to the external electrodes 20a and 20b, the difference between thicknesses T0 and T2 is larger than the difference between thicknesses T3 and T2. The difference between the thicknesses T0 and T2, and the difference between the thicknesses T3 and T2 are each 10-40 μm.

Description

  The present invention relates to a multilayer ceramic electronic component, and in particular, has a ceramic body in which internal electrodes are embedded and external electrodes formed on end faces of the ceramic body so as to be electrically connected to the internal electrodes. The present invention relates to a multilayer ceramic electronic component such as a multilayer ceramic capacitor, a multilayer ceramic inductor, a multilayer ceramic thermistor, and a multilayer ceramic piezoelectric component.

  As a conventional multilayer ceramic electronic component, for example, as disclosed in Patent Document 1, a metal is a main component on both end faces of a ceramic body where the internal electrodes are exposed on the surface of the ceramic body in which the internal electrodes are embedded. An external electrode having a sintered electrode layer containing, a conductive resin electrode layer containing metal particles formed on the surface of the sintered electrode layer, and a plating layer formed on the surface of the conductive resin electrode layer Is known. In this multilayer ceramic electronic component, since the conductive resin electrode layer is formed between the sintered electrode layer and the plating layer, the ceramic body is cracked or mounted on the substrate in the temperature cycle during use. In some cases, the disadvantage of being weak in strength against the deflection of the substrate is solved to some extent.

JP-A-10-284343

  However, the conventional multilayer ceramic electronic component described above has a problem that the equivalent series resistance generally tends to increase because the conductive resin electrode layer contains metal particles and synthetic resin. In a multilayer ceramic electronic component, if the equivalent series resistance is high, a problem such as signal reflection occurs when used in a high-frequency circuit.

  Therefore, a main object of the present invention is to provide a multilayer ceramic electronic component capable of keeping the equivalent series resistance low.

The multilayer ceramic electronic component according to the present invention has an internal electrode embedded therein, a first main surface, a second main surface opposite to the first main surface, and the first main surface and the second main surface. A first side surface to be connected, a second side surface facing the first side surface, a first main surface, a second main surface, a first side surface and a first end surface connected to the second side surface; A ceramic body having a second end face opposed to the first end face, and an end face of the ceramic body and at least the first main face or the second main face so as to be electrically connected to the internal electrode An external electrode, and the external electrode includes, in order from the ceramic body side, a sintered metal layer, a conductive resin layer, and a plating layer. Including metal particles, the internal electrodes are layered and stacked in the direction connecting the main surfaces of the ceramic body. The first and second regions are arranged in order from the first main surface side of the ceramic body in the stacking direction at the position of the internal electrode arranged on the most main surface side of the ceramic body. When the first and third regions are divided into three regions, the thickness T0 of the external electrode at the position of the main surface of the ceramic body and the most main surface side of the ceramic body are arranged in the first region and the third region. The difference between the position of the internal electrode and the thickness T2 of the external electrode is t1, and in the second region, the thickness T3 of the external electrode and the position of the internal electrode disposed on the most main surface side of the ceramic body are When the difference from the thickness T2 of the external electrode is t2, t1> t2, and t1 and t2 each satisfy a relationship of 10 μm or more and 40 μm or less.
In the multilayer ceramic electronic component according to the present invention, in the external electrode, the thickness T5 of the portion formed on at least the first main surface or the second main surface of the ceramic body is the portion formed on the end surface of the ceramic body. It is preferable that the thickness is larger than the thickness T3.
In the multilayer ceramic electronic component according to the present invention, the plating layer includes a Ni plating layer, and the thickness of the Ni plating layer is preferably 1 μm to 5 μm.

In the multilayer ceramic electronic component according to the present invention, t1> t2, and t1 and t2 satisfy a relationship of 10 μm to 40 μm, respectively.
Therefore, in the multilayer ceramic electronic component according to the present invention, the external electrode has a shape that swells thick toward the center, but the amount of bulge at the center is less than the amount of bulge near the outer layer. .
Therefore, in the multilayer ceramic electronic component according to the present invention, since the external electrode can be formed thin and flat, the equivalent series resistance can be kept low.
In the multilayer ceramic electronic component, if the amount of expansion of the external electrode is too large, the external electrode becomes thick and the equivalent series resistance increases.
In the multilayer ceramic electronic component according to the present invention, when the multilayer ceramic electronic component is mounted on the mounting substrate, tensile stress is applied to the external electrodes at both ends of the ceramic body, but the external electrode expands toward the center. Therefore, it is easy to relieve stress.
In the multilayer ceramic electronic component, when the external electrode is completely flat, it is difficult to relax the stress.
In the multilayer ceramic electronic component according to the present invention, in the external electrode, the thickness T5 of the portion formed on at least the first main surface or the second main surface of the ceramic body is the portion formed on the end surface of the ceramic body. When the thickness is larger than T3, when the multilayer ceramic electronic component is mounted on the mounting substrate, the external electrode on the mounting substrate side is thick, so that stress applied to the multilayer ceramic electronic component can be easily relaxed.
In the multilayer ceramic electronic component according to the present invention, when the plating layer includes the Ni plating layer and the thickness of the Ni plating layer is 1 μm to 5 μm, the external electrode is flat to some extent, but the Ni plating layer is thick, so the Ni plating Since the layer can confine moisture inside the plating layer rather than the plating layer, for example, during reflow mounting, solder explosion in which moisture inside the plating layer explodes together with the solder is prevented.

  According to the present invention, a multilayer ceramic electronic component that can keep the equivalent series resistance low can be obtained.

  The above-described object, other objects, features, and advantages of the present invention will become more apparent from the following description of embodiments for carrying out the invention with reference to the drawings.

It is a perspective view which shows an example of the multilayer ceramic capacitor concerning this invention. FIG. 2 is a cross-sectional view of the multilayer ceramic capacitor shown in FIG. 1 taken along line II-II in FIG. It is an illustration figure which shows the interface of the sintered metal layer and conductive resin layer in which the recessed part was formed. It is the elements on larger scale which show the cross section of the center part in the width direction of the multilayer ceramic capacitor shown in FIG. It is an illustration figure which shows the interface of the Ni plating layer in which the convex part was formed toward the conductive resin layer from the Ni plating layer, and the conductive resin layer. It is an illustration figure which shows the magnitude | size of the convex part shown in FIG. FIG. 2 is an illustrative view showing thicknesses T0, T1, T2, T3, T4, and T5 of each portion of an external electrode in the multilayer ceramic capacitor shown in FIG.

  A multilayer ceramic capacitor 10 shown in FIG. 1 includes, for example, a substantially rectangular parallelepiped ceramic body 12. The ceramic body 12 includes a plurality of laminated ceramic layers 14, and includes a first main surface 12a and a second main surface 12b facing each other, and a first side surface 12c and a second side surface 12d facing each other. The first end face 12e and the second end face 12f are opposed to each other. The first side surface 12c and the second side surface 12d are connected to the first main surface 12a and the second main surface 12b, respectively. The first end surface 12e and the second end surface 12f are connected to the first main surface 12a, the second main surface 12b, the first side surface 12c, and the second side surface 12d, respectively. The ceramic body 12 has rounded corners and ridges. The ceramic body 12 may be formed in other sizes and shapes.

As the ceramic material of the ceramic layer 14 of the ceramic body 12, for example, a dielectric ceramic composed of main components such as BaTiO ₃ , CaTiO ₃ , SrTiO ₃ , CaZrO ₃ can be used. Moreover, you may use what added subcomponents, such as a Mn compound, Fe compound, Cr compound, Co compound, Ni compound, to these main components. Moreover, the thickness of the ceramic layer 14 of the ceramic body 12 can be set to 0.5 μm to 10 μm, for example.

As shown in FIG. 2, for example, a plurality of first and second internal electrodes 16 a and 16 b having a substantially rectangular shape are alternately arranged at equal intervals along the thickness direction of the ceramic body 12. It is buried so that it may be arranged.
The first and second internal electrodes 16a and 16b have exposed portions 18a and 18b exposed at the first and second end surfaces 12e and 12f of the ceramic body 12, respectively, at one end portions of the first and second internal electrodes 16a and 16b. Specifically, the exposed portion 18 a at one end of the first internal electrode 16 a is exposed at the first end face 12 e of the ceramic body 12. The exposed portion 18 b at one end of the second internal electrode 16 b is exposed at the second end surface 12 f of the ceramic body 12.
Further, each of the first and second internal electrodes 16 a and 16 b is parallel to the first and second main surfaces 12 a and 12 b of the ceramic body 12. The first and second internal electrodes 16 a and 16 b face each other with the ceramic layer 14 in the thickness direction of the ceramic body 12.
Each thickness of the 1st and 2nd internal electrodes 16a and 16b can be 0.2 micrometer-2 micrometers, for example. However, the thickness of each of the first and second internal electrodes 16a and 16b is not particularly limited.
The first and second internal electrodes 16a and 16b contain, for example, Ni, which is a base metal, as a conductive material. The first and second internal electrodes 16a and 16b are made of, for example, a metal such as Ni, Cu, Ag, Pd, or Au, or an alloy such as an Ag—Pd alloy containing one of these metals. be able to.

First and second external electrodes 20a and 20b are formed on the first and second end faces 12e and 12f of the ceramic body 12, respectively.
The first external electrode 20a is formed from the first end surface 12e of the ceramic body 12 to the first and second main surfaces 12a, 12b and the first and second side surfaces 12c, 12d. In this case, the first external electrode 20a is electrically connected to the exposed portion 18a of the first internal electrode 16a.
The second external electrode 20b is formed from the second end face 12f of the ceramic body 12 to the first and second main faces 12a, 12b and the first and second side faces 12c, 12d. In this case, the second external electrode 20b is electrically connected to the exposed portion 18b of the second internal electrode 16b.

  The external electrode 20a includes a sintered metal layer 22a, a conductive resin layer 24a, and a plating layer 26a in this order from the ceramic body 12 side. Similarly, the external electrode 20b includes a sintered metal layer 22b, a conductive resin layer 24b, and a plating layer 26b in this order from the ceramic body 12 side.

  The sintered metal layers 22a and 22b each contain Cu, which is a base metal, as a main component, and are formed on the outer surface of the ceramic body 12, that is, on the first and second end faces 12e and 12f and the like. Are physically and electrically connected to the first and second internal electrodes 16a and 16b. The sintered metal layers 22a and 22b are formed by applying and baking a conductive paste containing Cu powder and glass powder on the outer surface of the ceramic body 12, respectively. The thickness of the sintered metal layers 22a and 22b is, for example, 10 μm to 30 μm, respectively.

  Each of the conductive resin layers 24a and 24b includes metal particles as a conductive material. The conductive resin layers 24a and 24b are formed on the sintered metal layers 22a and 22b so as to cover the sintered metal layers 22a and 22b, respectively, and a first metal powder of Cu or Ag serving as metal particles And a layer obtained by heating and curing a mixture of the second metal powder having a predetermined average particle diameter and the thermosetting resin.

  The sintered metal layers 22a and 22b are formed by applying and baking a conductive paste on the end face of the ceramic body 12, and at this time, as shown in FIG. 3, the sintered metal layers 22a and 22b are formed on the surfaces of the sintered metal layers 22a and 22b. A plurality of recesses 25 are formed. When the conductive resin layers 24a and 24b are formed on the sintered metal layers 22a and 22b, the conductive resin constituting the conductive resin layers 24a and 24b enters the recesses 25 on the surfaces of the sintered metal layers 22a and 22b. And may not get inside. That is, the concave portion 25 includes a concave portion 25a in which the conductive resin enters and a void concave portion 25b in which the conductive resin does not enter. When the conductive resin enters the concave portions 25 of the sintered metal layers 22a and 22b, the fixing strength between the sintered metal layers 22a and 22b and the conductive resin layers 24a and 24b can be increased due to the anchor effect. Therefore, in order to prevent peeling between the sintered metal layers 22a and 22b and the conductive resin layers 24a and 24b, it is preferable to reduce the gap recesses 25b in which the conductive resin does not enter.

  The observation of the concave portions 25 on the surfaces of the sintered metal layers 22a and 22b is a cross-section of the central portion in the width direction of the multilayer ceramic capacitor 10, that is, a surface composed of the length direction and the thickness direction of the multilayer ceramic capacitor 10, A cross section exposed by polishing up to the center of is used. At this time, surface treatment is performed so as not to cause polishing sagging and the like, and the interface between the sintered metal layers 22a and 22b and the conductive resin layers 24a and 24b is observed at a magnification of 1000 times using an optical microscope. The recess 25 is provided on the sintered metal layer side and opens on the conductive resin layers 24a and 24b side. Here, the concave portion 25 refers to a state in which the inner diameter dimension inside the concave portion is larger than the opening size of the inlet of the concave portion. In addition, a conductive resin enters the inside. And, in order to obtain a strong fixing strength between the sintered metal layers 22a and 22b and the conductive resin layers 24a and 24b, the number of void recesses 25b in the range of the interface length of 70 μm is 6 or less. Is preferred. At this time, it is preferable that the aperture of the cavity recess 25b is 1 μm to 3 μm in view of the cross section of the sintered metal layers 22a and 22b.

  The size of the recess 25 is defined by the diameter and depth along the interface direction. Here, the depth of the recess 25 is preferably in the range of 3 μm to 5 μm. Other than this value, it is difficult to obtain an anchor effect.

  The metal particles contained in the conductive resin layers 24a and 24b include flat flat particles and spherical spherical particles. As to whether the metal particles are flat or spherical, the cross section of the central portion in the width direction of the multilayer ceramic capacitor 10 and the cross sections of the conductive resin layers 24a and 24b are observed, and the conductive resin layers 24a, 24b, In the metal particles included in 24b, metal particles having a ratio of the long side to the short side of 5/1 or more are regarded as flat particles, and metal particles having a ratio of the long side to the short side of less than 5/1 are regarded as spherical particles. . The flat particles of the metal particles contained in the conductive resin layers 24a and 24b relieve the stress applied to the external electrodes 20a and 20b, and the spherical particles of the metal particles contained in the conductive resin layers 24a and 24b ensure electrical connection. .

  Furthermore, the ratio of the number of spherical particles to the number of flat particles of metal particles contained in the conductive resin layers 24a and 24b is 3/7 to 7/3. About the ratio, the cross section of the central part in the width direction of the multilayer ceramic capacitor 10 and the cross section including the conductive resin layers 24a and 24b is observed, and the spherical shape with respect to the number of flat particles in the cross section of the conductive resin layers 24a and 24b. The ratio of the number of particles is regarded as the ratio of the number of spherical particles to the number of flat particles.

  The cross section of the central portion in the width direction of the multilayer ceramic capacitor 10 observed as described above is a surface formed of the length direction and the thickness direction of the multilayer ceramic capacitor 10, and the multilayer ceramic capacitor 10 is solidified with a resin. A cross section exposed by polishing at a portion including the internal electrodes 16a and 16b and the external electrodes 20a and 20b up to the central portion in the width direction of 10 is used. Further, surface treatment is performed on the cross section so as not to cause polishing sagging and the like, and the cross section of the conductive resin layers 24a and 24b is observed using an SEM at a magnification of 1000 times, for example. FIG. 4 is a partially enlarged view showing the cross section.

  The ratio of the number of spherical particles to the number of flat particles of the metal particles contained in the conductive resin layers 24a and 24b is 3/7 to 7/3 when the ratio is larger than 7/3. This is because the number is small and the number of spherical particles is large, and electrical connection can be ensured, but stress relaxation cannot be performed sufficiently, and the ceramic body is likely to crack due to bending stress. On the other hand, when the ratio is smaller than 3/7, the number of flat particles is large and the number of spherical particles is small, and although the stress can be relieved, the electrical connection cannot be ensured and the equivalent series resistance increases. Because it ends up.

  As the second metal powder contained in the conductive resin layers 24a and 24b, base metal Ni or Sn is used. The shape of the second metal powder may be any shape such as a spherical shape and a scale shape, and the average particle size is about 10 μm to 50 nm, which is extremely small.

  Although it does not restrict | limit especially as a thermosetting resin contained in the conductive resin layers 24a and 24b, For example, a phenol resin, an acrylic resin, a silicon resin, an epoxy resin, a polyimide resin etc. can be used.

  In the external electrode 20a, when a cross section including the interface between the sintered metal layer 22a and the conductive resin layer 24a is viewed, glass exists on the surface of the sintered metal layer 22a at the interface, and the glass along the interface When the length is L1 and the length of the metal portion other than the glass of the sintered metal layer 22a along the interface is L2, L1 / L2 is 0.2 or more and 1.5 or less. Similarly, in the external electrode 20b, when a cross section including the interface between the sintered metal layer 22b and the conductive resin layer 24b is viewed, glass is present on the surface of the sintered metal layer 22b at the interface, and along the interface. When the length of the glass is L1 and the length of the metal portion other than the glass of the sintered metal layer 22b along the interface is L2, L1 / L2 is 0.2 or more and 1.5 or less.

  The cross-section of the multilayer ceramic capacitor 10 observed in this way is a surface composed of the length direction and the thickness direction of the multilayer ceramic capacitor 10 in the same manner as the above-described cross section, and the multilayer ceramic capacitor 10 is solidified with a resin. A cross section exposed by polishing at a portion including the internal electrodes 16a and 16b and the external electrodes 20a and 20b up to the central portion in the width direction of 10 is used. Further, as in the case described above, the cross section is subjected to surface treatment so as not to cause polishing sagging and the like, and the cross section of the external electrodes 20a and 20b is observed using a SEM, for example, at a magnification of 1000 times. FIG. 4 is a partially enlarged view showing the cross section.

  In the external electrode 20a (20b), when a cross section including an interface between the sintered metal layer 22a (22b) and the conductive resin layer 24a (24b) is viewed, the interface is formed on the surface of the sintered metal layer 22a (22b). When glass is present, the length of the glass along the interface is L1, and the length of the metal portion other than the glass of the sintered metal layer 22a (22b) along the interface is L2, L1 / L2 is When L1 / L2 is larger than 1.5, the glass is increased at the interface between the sintered metal layer 22a (22b) and the conductive resin layer 24a (24b). This is because the resistance value between () increases. On the other hand, when L1 / L2 is smaller than 0.2, the glass in the sintered metal layer 22a (22b) decreases, and the fixing strength between the sintered metal layer 22a (22b) and the ceramic body 12 becomes weak. Because.

  Further, in order to increase the fixing strength between the sintered metal layer 22a (22b) and the ceramic body 12, it is necessary to include a certain amount or more of glass in the sintered metal layer 22a (22b). When the sintered metal layer 22a (22b) is baked on the element body 12, glass is deposited on the surface of the sintered metal layer 22a (22b). That is, glass is deposited at the interface between the sintered metal layer 22a (22b) and the conductive resin layer 24a (24b), and the length of the glass along the interface is preferably 10 μm or more and 30 μm or less. . If the length of the glass is less than 10 μm, it means that sufficient glass is not contained, and the fixing strength between the sintered metal layer 22a (22b) and the ceramic body 12 becomes weak. Moreover, since the contact area between the conductor of sintered metal layer 22a (22b) and the conductor of conductive resin layer 24a (24b) cannot be ensured when the length of the glass exceeds 30 micrometers, those As a result, the equivalent series resistance tends to increase.

  The plating layer 26a includes a Ni plating layer 28a and a Sn plating layer 30a. Similarly, the plating layer 26b includes a Ni plating layer 28b and a Sn plating layer 30b.

  The Ni plating layers 28a and 28b are formed by subjecting the surfaces of the conductive resin layers 24a and 24b and the like to electrolytic plating with Ni, and their thicknesses are, for example, 1 μm to 5 μm. The Ni plating layers 28a and 28b function as barrier layers.

  Here, the conductive resin layers 24a and 24b are formed by applying a conductive resin on the sintered metal layers 22a and 22b and thermosetting them. At this time, a plurality of recesses can be formed on the surfaces of the conductive resin layers 24a and 24b by adjusting the curing conditions of the conductive resin. Further, after forming the conductive resin layers 24a and 24b, a concave portion may be formed on the surfaces of the conductive resin layers 24a and 24b by applying a physical external force such as sandblasting.

  Ni plating layers 28a and 28b are formed on the conductive resin layers 24a and 24b where the recesses are formed. At this time, since the recesses are formed on the surfaces of the conductive resin layers 24a and 24b, as shown in FIG. 5, the Ni plating layers 28a and 28b enter into the recesses, and the conductive resin from the Ni plating layers 28a and 28b. Protrusions 29 extending toward the layers 24a and 24b are formed. At this time, the depth of the convex portion 29 protruding from the Ni plating layers 28a, 28b on the surface of the conductive resin layers 24a, 24b into the concave portions of the conductive resin layers 24a, 24b is in the range of 1.0 μm to 7.0 μm. It is preferable to be within. When the depth of the convex portion 29 is less than 1.0 μm, the Ni plating layers 28a and 28b are not sufficiently penetrated into the conductive resin layers 24a and 24b, and a sufficient anchor effect cannot be obtained. Further, when the depth of the convex portion 29 exceeds 7.0 μm, the Ni plating is applied to the conductive resin layers 24a and 24b, the surfaces of the Ni plating layers 28a and 28b are recessed, and the substrate of the multilayer ceramic capacitor 10 The mountability to becomes worse. In order to eliminate such a dent, it is conceivable to make the Ni plating sufficiently thick. However, in order to increase the plating thickness, it is necessary to lengthen the plating time, which is not preferable in terms of production efficiency.

  The protrusions 29 extending from the Ni plating layers 28 a and 28 b toward the conductive resin layers 24 a and 24 b are observed in the cross section of the multilayer ceramic capacitor 10. The cross section is a surface formed of the length direction and the thickness direction of the multilayer ceramic capacitor 10, and a cross section exposed by polishing up to the center in the width direction is used. Further, the surface treatment is performed so as not to cause polishing sagging and the like, and the interface between the conductive resin layers 24a and 24b and the Ni plating layers 28a and 28b is observed using an SEM at a magnification of 1000 times. Here, as shown in FIG. 6, the size of the convex portion 29 is the larger value of the depths of the convex portion 29 measured from the Ni plating layer surfaces on both sides of the convex portion 29.

  Furthermore, the Sn plating layers 30a and 30b are formed by subjecting the surfaces of the Ni plating layers 28a and 28b to electrolytic plating with Sn, and each thickness is, for example, 1 μm to 5 μm. The Sn plating layers 30a and 30b function to improve solderability.

  In the external electrode 20a, when the cross section including the interface between the conductive resin layer 24a and the plating layer 26a is viewed, the number of exposed metal particles from the conductive resin layer 24a is determined by the number of the conductive resin layer 24a and the plating layer 26a. 50 to 250 per 1 mm of the interface length. Similarly, when the cross section including the interface between the conductive resin layer 24b and the plating layer 26b is seen in the external electrode 20b, the number of exposed metal particles from the conductive resin layer 24b is the same as that of the conductive resin layer 24b. The number is 50 to 250 per 1 mm of the length of the interface with the plating layer 26b.

  The cross-section of the multilayer ceramic capacitor 10 observed in this way is a surface composed of the length direction and the thickness direction of the multilayer ceramic capacitor 10 in the same manner as the above-described cross section, and the multilayer ceramic capacitor 10 is solidified with a resin. A cross section exposed by polishing at a portion including the internal electrodes 16a and 16b and the external electrodes 20a and 20b up to a central portion in the width direction of 10 is used. Similarly to the case described above, surface treatment is performed on the cross section so as not to cause polishing sagging and the like, and the cross sections of the conductive resin layers 24a and 24b are observed using a SEM, for example, at a magnification of 1000 times. FIG. 4 is a partially enlarged view showing the cross section.

  In the external electrode 20a (20b), when a cross section including the interface between the conductive resin layer 24a (24b) and the plating layer 26a (26b) is viewed, the metal particles are exposed from the conductive resin layer 24a (24b). The number of 50 to 250 per 1 mm of the interface length between the conductive resin layer 24a (24b) and the plating layer 26a (26b) is exposed when the number is less than 50. This is because electrolytic concentration occurs in few metal particles, water is electrolyzed, hydrogen is generated, and this hydrogen may cause defects in the plating layer 26a (26b). On the other hand, when the number is more than 250, the amount of the resin in the conductive resin layer 24a (24b) is reduced, and the multilayer ceramic capacitor with respect to the deflection of the substrate when the multilayer ceramic capacitor 10 is mounted on the substrate. This is because 10 may be weak in strength.

  The multilayer ceramic capacitor 10 is formed, for example, in a substantially rectangular parallelepiped shape having a length L of 1 mm, a width W of 0.5 mm, and a thickness T of 0.5 mm.

  In the multilayer ceramic capacitor 10, the internal electrodes 16 a and 16 b are layered and are stacked in a direction connecting the main surfaces 12 a and 12 b of the ceramic body 12.

  Further, in this multilayer ceramic capacitor 10, the external electrodes 20a, 20b are arranged at the positions of the internal electrodes 16a, 16b arranged on the most main surfaces 12a, 12b side of the ceramic body 12 in the stacking direction of the internal electrodes 16a, 16b. When the ceramic body 12 is divided into three regions of the first region, the second region, and the third region in order from the first main surface 12a side, as shown in FIG. In the region 3, the thickness of the external electrodes 20a, 20b at the positions of the main surfaces 12a, 12b of the ceramic body 12 is T0, and the internal electrodes 16a, 16b disposed on the most main surfaces 12a, 12b side of the ceramic body 12 The thickness of the sintered metal layers 22a and 22b at the position T1 is T1, and the positions of the internal electrodes 16a and 16b disposed on the most main surfaces 12a and 12b side of the ceramic body 12 are as follows. The thickness of the partial electrodes 20a and 20b is T2, the thickest thickness of the external electrodes 20a and 20b is T3, and the thickest thickness of the sintered metal layers 22a and 22b is T4 in the second region. The thickness of the portion formed on the first main surface 12a or the second main surface 12b is T5. When the difference between the thickness T0 and the thickness T2 is t1, and the difference between the thickness T0 and the thickness T3 is t2, t1> t2, and t1 and t2 satisfy the relationship of 10 μm or more and 40 μm or less, respectively. Furthermore, the thickness T5 is thicker than the thickness T3. The thicknesses T0, T1, T2, T3, and T4 of the external electrodes 20a and 20b are the thicknesses in the length direction of the multilayer ceramic capacitor 10, and the thickness T5 of the external electrodes 20a and 20b is the multilayer ceramic capacitor 10. It is the thickness in the thickness direction.

  In this multilayer ceramic capacitor 10, since the ratio of the number of spherical particles to the number of flat particles of metal particles contained in the conductive resin layers 24a and 24b is 3/7 to 7/3, stress relaxation and electrical connection are achieved. And balance. Therefore, the multilayer ceramic capacitor 10 can provide good electrical characteristics as well as good resistance.

  Furthermore, in this multilayer ceramic capacitor 10, the number of void recesses in the range of the interface length of 70 μm at the interface between the sintered metal layers 22a and 22b and the conductive resin layers 24a and 24b in the cross section of the multilayer ceramic capacitor 10 is obtained. By setting the number to 6 or less, the adhesion between the sintered metal layers 22a and 22b and the conductive resin layers 24a and 24b can be increased.

  In this multilayer ceramic capacitor 10, since L1 / L2 is 0.2 or more and 1.5 or less, the resistance value between the sintered metal layers 24a and 24b and the conductive resin layers 24a and 24b can be kept low, Adhesive strength between the sintered metal layers 24a and 24b and the ceramic body 12 is sufficient. Therefore, in this multilayer ceramic capacitor 10, the equivalent series resistance can be kept low.

  Further, in this multilayer ceramic capacitor 10, when a cross section including the interface between the conductive resin layer 24a (24b) and the plating layer 26a (26b) is viewed, the conductive resin layer 24a (24b) at the interface is Since 50 to 250 metal particles exist per 1 mm of the interface length, electrolytic concentration does not occur in the metal particles, so that generation of hydrogen can be suppressed, and defects in the plating layer 26a (26b) can be prevented. Moreover, when it is mounted on the substrate, it is sufficient in strength against the deflection of the substrate.

  Further, in this multilayer ceramic capacitor 10, since the convex portions are formed from the Ni plating layers 28a, 28b toward the conductive resin layers 24a, 24b, the conductive resin layers 24a, 24b and the Ni plating are caused by the anchor effect. Peeling hardly occurs between the layers 28a and 28b. Therefore, even if reflow soldering is performed in order to mount the multilayer ceramic capacitor 10 on a substrate, moisture contained in the conductive resin layers 24a and 24b is not ejected, and solder explosion can be prevented.

In this multilayer ceramic capacitor 10, t1> t2, and t1 and t2 satisfy a relationship of 10 μm or more and 40 μm or less, respectively.
Therefore, in this multilayer ceramic capacitor 10, the external electrodes 20a and 20b are shaped to swell thickly toward the center, but the amount of bulge at the center is less than the amount of bulge near the outer layer. .
Therefore, in this multilayer ceramic capacitor 10, since the external electrodes 20a and 20b can be formed thin and flat, the equivalent series resistance can be kept low.
In the multilayer ceramic capacitor 10, if the amount of swelling of the external electrodes 20a and 20b becomes too large, the external electrodes 20a and 20b become thick and the equivalent series resistance increases.

Further, in this multilayer ceramic capacitor 10, when the multilayer ceramic capacitor 10 is mounted on the mounting substrate, tensile stress is applied to the external electrodes 20a, 20b at both ends of the ceramic body 12, but the external electrodes 20a, 20b are in the central portion. It is easy to relieve stress.
In the multilayer ceramic capacitor 10, when the external electrodes 20a and 20b are completely flat, it is difficult to relieve stress.

  Further, in the multilayer ceramic capacitor 10, since the metal particles of the conductive resin layers 24a and 24b contain Cu or Ag, good conductivity is ensured in the conductive resin layers 24a and 24b.

  Furthermore, in this multilayer ceramic capacitor 10, since the sintered metal layers 22a and 22b contain Cu, good conductivity is ensured in the sintered metal layers 22a and 22b.

  Moreover, in this multilayer ceramic capacitor 10, since the plating layers 26a and 26b include the Ni plating layers 28a and 28b, moisture inside the plating layers 26a and 26b can be confined by the Ni plating layers 28a and 28b. At the time of mounting by reflow, solder explosion in which moisture inside the plating layers 26a and 26b explodes together with the solder is prevented.

  In the multilayer ceramic capacitor 10, the thickness T5 of the portion formed on the first main surface 12a or the second main surface 12b of the ceramic body 12 in the external electrodes 20a and 20b is equal to the end surfaces 12e and 12f of the ceramic body 12. Since the thickness of the external electrodes 20a and 20b on the mounting substrate side becomes thick when the multilayer ceramic capacitor 10 is mounted on the mounting substrate, the stress applied to the multilayer ceramic capacitor 10 is increased. Easy to relax.

  Moreover, in this multilayer ceramic electronic component 10, since the plating layers 26a and 26b include Ni plating layers 28a and 28b and the thicknesses of the Ni plating layers 28a and 28b are 1 μm to 5 μm, the external electrodes 20a and 20b are somewhat flat. However, since the Ni plating layers 28a and 28b are thick, moisture inside the plating layers 26a and 26b can be confined by the Ni plating layers 28a and 28b. For example, when mounting by reflow, the plating layers 26a and 26b Also, the solder explosion that the internal moisture etc. explodes together with the solder is prevented.

  Further, in this multilayer ceramic capacitor 10, since the external electrodes 20a and 20b are formed on the first main surface 12a and the second main surface 12b of the ceramic body 12, the first main surface 12a and the second main surface 12b are formed. It is easy to mount either main surface of the main surface 12b as a mounting surface.

  Further, in this multilayer ceramic capacitor 10, since the external electrodes 20a and 20b are also formed on the side surfaces 12c and 12d of the ceramic body 12, there is an effect of improving the moisture resistance reliability.

  Next, an example of a method for manufacturing the above-described multilayer ceramic capacitor 10 will be described.

  First, a ceramic green sheet containing a ceramic material for constituting the ceramic body 12 (ceramic layer 14) is prepared.

  Next, a conductive pattern is formed on the ceramic green sheet by applying a conductive paste. The conductive paste can be applied by various printing methods such as a screen printing method. The conductive paste may contain a known binder or solvent in addition to the conductive fine particles.

  A plurality of ceramic green sheets on which no conductive pattern is formed; a ceramic green sheet on which a conductive pattern having a shape corresponding to the first or second internal electrode is formed; and a plurality of ceramic green sheets on which no conductive pattern is formed. The ceramic green sheets are laminated in this order and pressed in the laminating direction to produce a mother laminated body.

  Then, by cutting the mother laminate along a virtual cut line on the mother laminate, a plurality of raw ceramic laminates are produced from the mother laminate. Note that the cutting of the mother laminate can be performed by dicing or pressing. The raw ceramic laminate may be subjected to barrel polishing or the like to round the ridge line portion or the corner portion.

  Then, the raw ceramic laminate is fired. In the firing step, the first and second internal electrodes are fired. The firing temperature can be appropriately set depending on the type of ceramic material and conductive paste used. The firing temperature can be, for example, 900 ° C. to 1300 ° C.

  Then, a conductive paste is applied to both ends of the fired ceramic laminate (ceramic body) by a method such as dipping.

  Next, the conductive paste applied to the ceramic laminate is dried with hot air, for example, at 60 ° C. to 180 ° C. for 10 minutes.

  Thereafter, the dried conductive paste is baked to form a sintered metal layer. At this time, the number of the recessed parts formed in the surface of a sintered metal layer can be changed by changing the baking temperature for obtaining a sintered metal layer. And by adjusting the diameter and depth of the concave portion on the surface of the sintered metal layer, the conductive resin entering the concave portion can be adjusted, and the large adhesion between the sintered metal layer and the conductive resin layer. Can be obtained.

Then, on the sintered metal layer, a mixture of a first metal powder of Cu or Ag that becomes metal particles of the conductive resin layer, a second metal powder having a predetermined average particle diameter, and a thermosetting resin Is heated and cured to form a conductive resin layer.
In this case, in order to set the ratio of the number of spherical particles to the number of flat particles of the metal particles contained in the conductive resin layer to 3/7 to 7/3, for example, in the material of the conductive resin layer, the flat particles and It is possible by adjusting the ratio of the material that becomes the spherical particles, or by adjusting the conductive resin layer forming conditions such as the heating temperature of the mixture that becomes the material of the conductive resin layer.
In this case, when the cross section including the interface between the conductive resin layer and the plating layer is viewed, the number of exposed metal particles from the conductive resin layer is determined by the length of the interface between the conductive resin layer and the plating layer. In order to obtain 50 to 250 per 1 mm, for example, the ratio of the first metal powder, the second metal powder and the thermosetting resin in the material of the conductive resin layer is adjusted, or the conductive resin layer This is possible by adjusting the conductive resin layer forming conditions such as the heating temperature of the mixture as the material.
Similarly, a recess can be formed on the surface of the conductive resin layer by adjusting the formation conditions of the conductive resin layer. Moreover, a recessed part can be formed in the surface of a conductive resin layer also by physical external forces, such as sandblasting.

  Then, the multilayer ceramic capacitor 10 can be manufactured by applying plating layers (Ni plating layer and Sn plating layer) on the conductive resin layer by electrolytic plating. In addition, by forming a concave portion on the surface of the conductive resin layer, Ni plating enters the concave portion, and a convex portion can be formed from the Ni plated layer toward the conductive resin layer side.

(Experimental example)
First, as an example, 20 multilayer ceramic capacitors 10 according to the above-described embodiment were produced.
Further, as a comparative example, 20 multilayer ceramic capacitors (samples 1 to 5) each having t1 (T0-T2) not larger than t2 (T3-T2) as compared with the example were manufactured.
The multilayer ceramic capacitors of Examples and Comparative Examples are the same as the multilayer ceramic capacitor except for the length L, width W, and thickness T, and the thicknesses T0, T1, T2, T3, T4, and T5 of each part of the external electrode. The design is the same.
And the equivalent series resistance was measured about the multilayer ceramic capacitor of the Example and the comparative example.
The results are shown in Table 1.

From the results shown in Table 1, in the samples 1 to 5 of the comparative example, the equivalent series resistance was as large as 11.5 mΩ or more as an average of 20 pieces, whereas in the example, the equivalent series resistance was 20 pieces. The average was as small as 8.2 mΩ.
Therefore, in the multilayer ceramic capacitor of the example according to the present invention, it can be seen that the equivalent series resistance can be suppressed lower than that of the multilayer ceramic capacitor (samples 1 to 5) of the comparative example.

  In the above-described embodiment and example, the external electrode is also formed on the side surface of the ceramic body, but the external electrode may not be formed on the side surface of the ceramic body. The external electrode may be formed on the end surface of the ceramic body and at least the first main surface or the second main surface. If the external electrodes of the multilayer ceramic electronic component are formed in this way, it is easy to mount the multilayer ceramic electronic component using the first main surface or the second main surface on which the external electrode is formed as a mounting surface.

  In the above-described embodiments and examples, the plating layer is composed of a Ni plating layer and a Sn plating layer, but the plating layer may be composed of one plating layer or three or more plating layers. Good.

In the above-described embodiments and examples, the dielectric ceramic is used as the material of the ceramic body. In the present invention, depending on the type of the multilayer ceramic electronic component, the ceramic body material may be a magnetic ceramic such as ferrite. Further, semiconductor ceramics such as spinel ceramics, and piezoelectric ceramics such as PZT ceramics can also be used.
The multilayer ceramic electronic component functions as a multilayer ceramic inductor when using a ceramic ceramic as a ceramic body, as a multilayer ceramic thermistor when using a semiconductor ceramic, and as a multilayer ceramic when using a piezoelectric ceramic. Functions as a piezoelectric component. However, when the multilayer ceramic electronic component functions as a multilayer ceramic inductor, the internal electrode is a coiled conductor.

  In the above-described embodiment and examples, the multilayer ceramic capacitor having a specific configuration has been described as an example. However, the configuration of the multilayer ceramic capacitor according to the present invention is within the range defined by the claims. It may be arbitrarily changed.

  The ceramic electronic component according to the present invention is particularly preferably used as, for example, a multilayer ceramic capacitor, a multilayer ceramic inductor, a multilayer ceramic thermistor, a multilayer ceramic piezoelectric component, or the like.

DESCRIPTION OF SYMBOLS 10 Multilayer ceramic capacitor 12 Ceramic body 12a, 12b Main surface 12c, 12d Side surface 12e, 12f End surface 14 Ceramic layer 16a, 16b Internal electrode 18a, 18b Exposed part 20a, 20b External electrode 22a, 22b Sintered metal layer 24a, 24b Conductivity Resin layer 25 Concave portion 26a, 26b Plating layer 28a, 28b Ni plating layer 29 Convex portion 30a, 30b Sn plating layer

Claims (3)

An internal electrode embedded; a first main surface; a second main surface opposite to the first main surface; and a first side surface connected to the first main surface and the second main surface A second side surface facing the first side surface, the first main surface, the second main surface, the first side surface and the first end surface connected to the second side surface, A ceramic body having a second end face facing the first end face;
A multilayer ceramic electronic component comprising an end face of the ceramic body and an external electrode formed on at least the first main surface or the second main surface so as to be electrically connected to the internal electrode. There,
The external electrode, in order from the ceramic body side, comprises a sintered metal layer, a conductive resin layer and a plating layer,
The conductive resin layer includes metal particles,
The internal electrode is layered, and is laminated in a direction connecting the main surfaces of the ceramic body.
The first electrode, the second region, and the outer electrode are arranged in order from the first main surface side of the ceramic element body in the stacking direction at the position of the inner electrode arranged on the most main surface side of the ceramic element body. When divided into three areas of the third area,
In the first region and the third region, the thickness T0 of the external electrode at the position of the main surface of the ceramic body and the position of the external electrode at the position of the internal electrode disposed on the most main surface side of the ceramic body. The difference from the thickness T2 is t1,
In the second region, when the difference between the thickest thickness T3 of the external electrode and the thickness T2 of the external electrode at the position of the internal electrode disposed on the most principal surface side of the ceramic body is t2,
A multilayer ceramic electronic component, wherein t1> t2 and t1 and t2 satisfy a relationship of 10 μm or more and 40 μm or less, respectively.   In the external electrode, at least the thickness T5 of the portion formed on the first main surface or the second main surface of the ceramic body is thicker than the thickness T3 of the portion formed on the end surface of the ceramic body. The multilayer ceramic electronic component according to claim 1, wherein:   The multilayer ceramic capacitor according to claim 1, wherein the plating layer includes a Ni plating layer, and the thickness of the Ni plating layer is 1 μm to 5 μm.