Source: https://patents.google.com/patent/TWI501272B/en
Timestamp: 2020-01-20 14:37:08
Document Index: 99649589

Matched Legal Cases: ['art 13', 'art 13', 'arts\n10', 'art\n10', 'art 1', 'art 2', 'art 3', 'art 1', 'art 2', 'art 3', 'art 1', 'art 2', 'art 3', 'art 1', 'art 2', 'art 3', 'art 2']

TWI501272B - Ceramic electronic component - Google Patents
TWI501272B
TWI501272B TW100122590A TW100122590A TWI501272B TW I501272 B TWI501272 B TW I501272B TW 100122590 A TW100122590 A TW 100122590A TW 100122590 A TW100122590 A TW 100122590A TW I501272 B TWI501272 B TW I501272B
TW100122590A
TW201222591A (en
2011-06-28 Application filed by Murata Manufacturing Co filed Critical Murata Manufacturing Co
2012-06-01 Publication of TW201222591A publication Critical patent/TW201222591A/en
2015-09-21 Publication of TWI501272B publication Critical patent/TWI501272B/en
The invention relates to a ceramic electronic component.
In recent years, with the miniaturization and thinning of electronic devices such as mobile phones and portable music players, the miniaturization of wiring boards mounted in electronic devices has been progressing. Along with this, the miniaturization and thinning of ceramic electronic components mounted on a wiring board are also progressing.
A ceramic electronic component having a ceramic substrate having a prismatic shape has a relatively high mechanical strength, but has a low mechanical strength in a ceramic electronic component having a flat-shaped ceramic substrate after thinning. Further, the thinner the thickness of the ceramic substrate, the lower the mechanical strength of the ceramic electronic component. Therefore, in ceramic electronic parts having a flat ceramic matrix, how to improve mechanical strength is an important issue.
As a method of improving the mechanical strength of the ceramic electronic component, for example, as described in the following patent documents, a method of forming a reinforcing conductor layer (buffer layer) inside the ceramic substrate is exemplified.
[Patent Document 1] Japanese Patent Laid-Open No. 11-26295
However, even when a reinforcing conductor layer is provided inside the ceramic base, cracks may not be sufficiently suppressed in the ceramic electronic component, and the mechanical durability of the ceramic electronic component may not be sufficiently improved.
The present invention has been made in view of the above circumstances, and an object thereof is to provide a ceramic electronic component excellent in mechanical durability.
The ceramic electronic component of the present invention includes a rectangular parallelepiped ceramic substrate, first and second internal electrodes, a first external electrode, and a second external electrode. The ceramic base has first and second main faces, first and second side faces, and first and second end faces. The first and second main faces extend in the longitudinal direction and the width direction. The first and second side faces extend in the longitudinal direction and the thickness direction. The first and second end faces extend in the width direction and the thickness direction. The first and second internal electrodes are formed inside the ceramic base. The first and second internal electrodes extend in the longitudinal direction and the width direction. The first and second internal electrodes face each other in the thickness direction. The first external electrode is formed on the ceramic substrate. The first external electrode is electrically connected to the first internal electrode. The second external electrode is formed on the ceramic substrate. The second external electrode is electrically connected to the second internal electrode. Each of the first and second external electrodes has a first portion located at an end portion of the first main surface in the longitudinal direction and a second portion located at the first or second end surface. The ceramic base includes an effective portion in which the first and second internal electrodes face in the thickness direction; a first outer layer portion closer to the first main surface than the effective portion; and a second outer surface side closer to the effective portion than the effective portion 2 outer layer. The ceramic electronic component of the present invention further includes a first reinforcing layer. The first reinforcing layer is formed in the first outer layer portion along the longitudinal direction and the width direction. A part of the first reinforcing layer faces the first portion of the first and second external electrodes in the thickness direction. The first reinforcing layer is not exposed from any of the first and second end faces. In the portion of the first main surface on which the first portion of the first or second external electrode is provided, the portion that does not face the reinforcing layer is closer to the center position in the thickness direction than the portion that faces the first reinforcing layer.
In a specific aspect of the ceramic electronic component of the present invention, in the first portion of each of the first and second external electrodes, the thickness ratio of the portion not facing the first reinforcing layer and the first reinforcing layer are opposed to each other. The thickness of the part is thick.
In another specific aspect of the ceramic electronic component of the present invention, each of the first and second external electrodes has a first or second end surface and an end portion of the first main surface in the longitudinal direction. a conductive layer; and a second conductive layer formed by covering the first conductive layer, and not facing the first reinforcing layer in a portion of the first conductive layer of each of the first and second external electrodes that constitutes the first portion The thickness of the portion is thicker than the thickness of the portion opposite to the first reinforcing layer.
In another specific aspect of the ceramic electronic component of the present invention, the first reinforcing layer is formed of a metal or an alloy. That is, in the present invention, the reinforcing layer may be constituted by a conductive layer.
In another specific aspect of the ceramic electronic component of the present invention, each of the first and second external electrodes further has a third portion located at an end portion of the second main surface in the longitudinal direction. The ceramic electronic component further includes a second reinforcing layer in the second outer layer, the second reinforcing layer being formed along the longitudinal direction and the width direction, and a part of the second reinforcing layer and the first and second external electrodes in the thickness direction. 3 parts are opposite. The second reinforcing layer is not exposed from any of the first and second end faces. In the portion of the second main surface on which the third portion of the first or second external electrode is provided, the portion that does not face the second reinforcing layer is closer to the center in the thickness direction than the portion that faces the second reinforcing layer. s position.
According to the present invention, the mechanical durability of ceramic electronic parts can be improved.
A preferred embodiment of the present invention will now be described by taking the ceramic electronic component 1 shown in Fig. 1 as an example. Among them, the ceramic electronic component 1 is merely an example. The present invention is not limited to the ceramic electronic component 1 shown below and a method of manufacturing the same.
Fig. 1 is a schematic perspective view showing a ceramic electronic component according to a first embodiment. Fig. 2 is a schematic side view showing a ceramic electronic component of the first embodiment. Fig. 3 is a schematic cross-sectional view taken along line III-III of Fig. 1. Fig. 4 is a schematic cross-sectional view showing a part of the ceramic electronic component of the first embodiment in an enlarged manner. Fig. 5 is a schematic cross-sectional view showing a line V-V of Fig. 3. Fig. 6 is a schematic cross-sectional view taken along line VI-VI of Fig. 3. Fig. 7 is a schematic cross-sectional view taken along line VII-VII of Fig. 3.
First, the configuration of the ceramic electronic component 1 will be described with reference to Figs. 1 to 7 .
As shown in FIGS. 1 to 7, the ceramic electronic component 1 is provided with a ceramic base 10. The ceramic base 10 is composed of a suitable ceramic material corresponding to the function of the ceramic electronic component 1. Specifically, when the ceramic electronic component 1 is a capacitor, the ceramic base 10 can be formed of a dielectric ceramic material. Specific examples of the dielectric ceramic material include BaTiO 3 , CaTiO 3 , SrTiO 3 , and CaZrO 3 . Further, the ceramic material may be used as a main component in the ceramic base 10 in accordance with the characteristics of the desired ceramic electronic component 1, and for example, a Mn compound, a Mg compound, a Si compound, an Fe compound, a Cr compound, a Co compound, or a Ni compound may be appropriately added. A subcomponent such as a rare earth compound.
In the case of a ceramic electronic component 1 type ceramic piezoelectric element, the ceramic base 10 can be formed using a piezoelectric ceramic material. Specific examples of the piezoelectric ceramic material include a PZT (lead zirconate titanate) ceramic material.
In the case of a ceramic electronic component 1 type thermistor element, the ceramic base 10 can be formed of a semiconductor ceramic material. Specific examples of the semiconductor ceramic material include a spinel ceramic material and the like.
In the case of a ceramic electronic component 1 based inductor element, the ceramic base 10 can be formed of a magnetic ceramic material. Specific examples of the magnetic ceramic material include ferrite ceramics and the like.
Next, in the present embodiment, an example of a ceramic electronic component 1 type ceramic capacitor will be described. More specifically, in the present embodiment, the ceramic electronic component 1 will be described as an example of a ceramic capacitor of a lower capacitance having a capacitance of about 0.1 nF to 100 nF.
The ceramic base 10 is formed in a rectangular parallelepiped shape. As shown in FIGS. 1 to 7, the ceramic base 10 has first and second main faces 10a and 10b, first and second side faces 10c and 10d, and first and second end faces 10e and 10f. As shown in FIGS. 1 to 3, the first and second main faces 10a and 10b extend in the longitudinal direction L and the width direction W. As shown in FIGS. 1 and 5 to 7, the first and second side faces 10c and 10d extend in the thickness direction T and the longitudinal direction L. As shown in FIGS. 2 to 7, the first and second end faces 10e and 10f extend in the thickness direction T and the width direction W.
In the present specification, the rectangular parallelepiped includes a rectangular parallelepiped having a corner or a ridge portion as an angular or R-angled shape. That is, the "capped" part means a part having all of the first and second main faces, the first and second side faces, and the first and second end faces. Further, a part or all of the main surface, the side surface, and the end surface may be formed with irregularities or the like. That is, the main surface, the side surface, and the end surface need not necessarily be flat.
The size of the ceramic base 10 is not particularly limited, but it is preferable that the ceramic base 10 satisfies T≦W<L, 1/5W when the thickness of the ceramic base 10 is T, the length is L, and the width is W. A thin ceramic substrate of T ≦ 1/2 W and T ≦ 0.3 mm. Specifically, it is preferably 0.1 mm ≦ T ≦ 0.3 mm, 0.4 mm ≦ L ≦ 1 mm, and 0.2 mm ≦ W ≦ 0.5 mm.
The thickness of the ceramic layer 10g is not particularly limited. The thickness of the ceramic layer 10g can be, for example, about 0.5 μm to 10 μm.
As shown in FIG. 3, inside the ceramic base 10, a plurality of substantially rectangular first and second internal electrodes 11 and 12 are alternately arranged at equal intervals in the thickness direction. The first and second internal electrodes 11 and 12 are parallel to the first and second main faces 10a and 10b, respectively.
As shown in FIGS. 3 and 5, the first inner electrode 11 is formed to extend in the longitudinal direction L and the width direction W. The first inner electrode 11 is exposed to the first end surface 10e of the ceramic base 10, and extends from the first end surface 10e toward the second end surface 10f. The first inner electrode 11 does not reach the second end surface 10f and each of the first and second side faces 10c and 10d. On the other hand, the second inner electrode 12 also extends in the longitudinal direction L and the width direction W. As shown in FIGS. 3 and 6, the second inner electrode 12 is exposed to the second end surface 10f of the ceramic base 10, and extends from the second end surface 10f toward the first end surface 10e side. The second inner electrode 12 does not reach the first end face 10e and each of the first and second side faces 10c and 10d. The first and second internal electrodes 11 and 12 are formed at the same position in the width direction W. Therefore, the first inner electrode 11 and the second inner electrode 12 face each other across the ceramic layer 10g at the central portion in the longitudinal direction L of the ceramic base 10. The first inner electrode 11 and the second inner electrode 12 do not face each other in the thickness direction T at both end portions of the ceramic base 10 in the longitudinal direction L.
The portion of the ceramic base 10 where the first and second internal electrodes 11 and 12 face each other constitutes an effective portion 10A that functions as a capacitor. The portion of the ceramic base 10 that is closer to the first main surface 10a than the effective portion 10A constitutes the first outer layer portion 10B, and the portion that is closer to the second main surface 10b than the effective portion 10A constitutes the second outer layer portion 10C.
Further, as described above, since the ceramic electronic component 1 is a ceramic capacitor having a low capacity, the ratio of the effective portion 10A to the ceramic base 10 is small. The length of the effective portion 10A along the thickness direction T is preferably about 0.1 to 0.5 times the length of the ceramic base 10 along the thickness direction T. The length of the effective portion 10A along the longitudinal direction L is preferably about 0.2 to 0.7 times the maximum length of the ceramic base 10 along the longitudinal direction L.
Further, it is preferable that the first and second internal electrodes 11 and 12 are, for example, one pair (one for each piece, two sheets in total) to ten pairs (for ten sheets each, for a total of 20 sheets).
Further, as shown in the present embodiment, in the case of a ceramic capacitor having a low capacitance, the distance between the first and second internal electrodes can be 2 to 8 layers of the ceramic layer 10g.
Further, first and second dummy electrodes 18 and 19 are provided inside the ceramic base 10. The first dummy electrode 18 is at the same position as the first internal electrode 11 in the thickness direction T, and is opposed to the first internal electrode 11 at intervals in the longitudinal direction L. Therefore, the first dummy electrode 18 is provided with the same number of sheets as the first internal electrode 11. On the other hand, the second dummy electrode 19 is at the same position in the thickness direction T and the second internal electrode 12, and is opposed to the second internal electrode 12 with a gap therebetween in the longitudinal direction L. Therefore, the second dummy electrode 19 is provided in the same number of sheets as the second internal electrode 12. Further, the first and second dummy electrodes 18 and 19 do not substantially contribute to the electrical characteristics of the ceramic electronic component 1.
Further, the material of each of the first and second internal electrodes 11 and 12 and the first and second dummy electrodes 18 and 19 is not particularly limited. The first and second internal electrodes 11 and 12 and the first and second dummy electrodes 18 and 19 can respectively be made of a metal such as Ni, Cu, Ag, Pd, Au, or the Ag-Pd alloy, and include one or more of these metals. Formed by the alloy. The first and second internal electrodes 11 and 12 and the first and second dummy electrodes 18 and 19 may be made of the same material or may be made of different materials.
The thickness of each of the first and second internal electrodes 11 and 12 and the first and second dummy electrodes 18 and 19 is not particularly limited. The thickness of each of the first and second internal electrodes 11 and 12 and the first and second dummy electrodes 18 and 19 can be, for example, about 0.3 μm to 2 μm. The first and second internal electrodes 11 and 12 and the first and second dummy electrodes 18 and 19 are preferably the same thickness.
As shown in FIGS. 1 to 3, first and second outer electrodes 13 and 14 are formed on the surface of the ceramic base 10. The first outer electrode 13 and the first inner electrode 11 are electrically connected. The first outer electrode 13 includes a first portion 13a formed on the first main surface 10a, a third portion 13c formed on the second main surface 10b, and a second portion 13b formed on the first end surface 10e. In the present embodiment, the first outer electrode 13 is formed to be shallowly wound around the end portions of the first and second side faces 10c and 10d in the longitudinal direction L. Specifically, the length of the first outer electrode 13 along the longitudinal direction L of the first and second side faces 10c and 10d is shorter than half of the length of the first and third portions 13a and 13c along the longitudinal direction L. Further, the length of the first and third portions 13a and 13c in the longitudinal direction L direction is preferably, for example, 200 μm to 350 μm. Further, the first outer electrode 13 hardly protrudes from the first and second side faces 10c and 10d in the width direction W. Thereby, the dimension W of the ceramic electronic component 1 in the width direction can be made small. Further, the first external electrode 13 may be substantially formed not on the first and second side faces 10c and 10d.
On the other hand, the second external electrode 14 and the second internal electrode 12 are electrically connected. The second outer electrode 14 includes a first portion 14a formed on the first main surface 10a, a third portion 14c formed on the second main surface 10b, and a second portion 14b formed on the second end surface 10f. In the present embodiment, the second outer electrode 14 is formed to be shallowly wound around the end portions of the first and second side faces 10c and 10d in the longitudinal direction L. Specifically, the length of the second outer electrode 14 along the longitudinal direction L of the first and second side faces 10c and 10d is shorter than half of the length of the first and third portions 14a and 14c along the longitudinal direction L. Further, the length of the first and third portions 14a and 14c in the longitudinal direction L direction is preferably, for example, 200 μm to 350 μm. Further, the second outer electrode 14 hardly protrudes from the first and second side faces 10c and 10d in the width direction W. Thereby, the dimension W of the ceramic electronic component 1 in the width direction can be made small. Further, the second external electrode 14 may not be substantially formed on the first and second side faces 10c and 10d.
Next, the configuration of the first and second external electrodes 13 and 14 will be described with reference to Fig. 3 . In the present embodiment, each of the first and second external electrodes 13 and 14 is formed by a laminate of the first conductive layer 15 and the second conductive layer 16.
The first conductive layer 15 is formed on the end portions of the first or second end faces 10e and 10f and the longitudinal direction L of the first or second main faces 10a and 10b.
The outer end portions of the first conductive layers 15 of the first and second outer electrodes 13 and 14 that constitute the first portions 13a and 14a in the longitudinal direction L are relatively thicker. In the same manner, the outer end portions of the first conductive layers 15 of the first and second outer electrodes 13 and 14 that constitute the third portions 13c and 14c in the longitudinal direction L are relatively thick. Specifically, in the portions of the first conductive layer 15 of the first and second portions 13 and 14 that constitute the first portions 13a and 14a, the thickness ratio of the portion that does not face the first reinforcing layer 17a and 1 The thickness of the portion opposite to the reinforcing layer 17a is thick. In the same manner, in the portion of the first conductive layer 15 of the first and second portions 13 and 14 that constitutes the third portions 13c and 14c, the thickness ratio of the portion that does not face the second reinforcing layer 17b and the second portion The thickness of the portion opposite to the reinforcing layer 17b is thick. Thus, in each of the first and third portions 13a, 14a, 13c, and 14c of the first and second external electrodes 13 and 14, the portion that does not face the first or second reinforcing layers 17a and 17b is not provided. The thickness ratio is thicker than the thickness of the portion facing the first or second reinforcing layers 17a and 17b. For example, the thickness of the outer end portion of the first conductive layer 15 can be approximately 5 μm to 10 μm, and the thickness of the inner end portion of the first conductive layer 15 is approximately 1 μm to 10 μm.
The thickness of the portion of the first conductive layer 15 formed on the first or second end faces 10e and 10f is thinner than the thickness of the portion of the first conductive layer 15 formed on the first or second main faces 10a and 10b. Further, the thickness of the portion of the second conductive layer 16 formed on the first or second end faces 10e and 10f is thinner than the thickness of the portion of the second conductive layer 16 formed on the first or second end faces 10e and 10f. . For example, the thickness of the portions of the conductive layers 15 and 16 formed on the first or second end faces 10e and 10f can be at most 3 to 10 μm.
The material of the first conductive layer 15 is not particularly limited. The first conductive layer 15 can be formed, for example, by a metal such as Ni, Cu, Ag, Pd, or Au, an Ag-Pd alloy, or an alloy including one or more of these metals. Further, the first conductive layer 15 may contain an inorganic bonding material. Examples of the inorganic binder include a ceramic material, a glass component, and the like which are the same as those of the ceramic material contained in the ceramic substrate 10. The content of the inorganic binder in the first conductive layer 15 is, for example, preferably in the range of 40% by volume to 60% by volume.
The second conductive layer 16 is formed to cover the end portions of the first and second main faces 10a and 10b in the longitudinal direction L and the first or second end faces 10e and 10f. The first conductive layer 15 is covered by the second conductive layer 16.
In the present embodiment, the second conductive layer 16 is formed of a laminated body of a single plating film or a plurality of plating films. The thickness of the second conductive film 16 is not particularly limited. The maximum thickness of the second conductive layer 16 can be, for example, about 5 μm to 15 μm.
The material of the second conductive layer 16 is also not particularly limited. The second conductive layer 16 can be formed, for example, from one metal selected from the group consisting of Cu, Ni, Sn, Pb, Au, Ag, Pd, Al, Bi, and Zn, or an alloy containing the metal. In particular, when the ceramic electronic component 1 is embedded in the wiring board, it is preferable to use one metal selected from the group consisting of Cu, Au, Ag, and Al as the metal constituting the outermost layer of the second conductive layer 16. Or an alloy containing the metal. This is because when the light is embedded, the first and second external electrodes 13 and 14 are aimed at and the laser light that has passed through the wiring substrate is irradiated, and these metals can efficiently reflect the laser light.
Further, for example, an additional layer such as a conductive resin layer for stress relaxation may be formed between the first conductive layer 15 and the second conductive layer 16.
As shown in FIGS. 3 and 7, a plurality of first reinforcing layers 17a are formed in the first outer layer portion 10B. A plurality of first reinforcing layers 17a are formed along the longitudinal direction L and the width direction W. A plurality of first reinforcing layers 17a are laminated in the thickness direction T. The plurality of first reinforcing layers 17a are not formed at both end portions of the ceramic base 10 in the longitudinal direction L. The plurality of first reinforcing layers 17a are continuously formed over the central portion excluding both end portions in the longitudinal direction L. A plurality of first reinforcing layers 17a are formed inside the ceramic base 10 and are not exposed from the surface of the ceramic base 10.
As shown in FIG. 3, a part of the plurality of first reinforcing layers 17a, specifically, the outer end portions of the plurality of first reinforcing layers 17a in the longitudinal direction L are in the thickness direction T and the first and second external electrodes 13, 14 The first part 13a, 14a is opposite. In other words, the outer end portions of the plurality of first reinforcing layers 17a in the longitudinal direction L face the first portions 13a and 14a of the first and second outer electrodes 13 and 14 in the thickness direction T.
The number of the first reinforcing layers 17a is not particularly limited. For example, the number of the first and second internal electrodes 11 and 12 can be 1.5 to 15 times. Specifically, the number of sheets of the first reinforcing layer 17a can be, for example, about three to 30 sheets. In the present embodiment, the case where a plurality of first reinforcing layers 17a are provided has been described. However, in the present embodiment, only the first reinforcing layer 17a of one layer may be provided.
The distance between the first reinforcing layers 17a adjacent in the thickness direction T is smaller than the distance between the first and second internal electrodes 11 and 12 adjacent to the thickness direction T. The distance between the first reinforcing layers 17a adjacent in the thickness direction T is preferably 0.125 to 0.5 times the distance between the first and second internal electrodes 11 and 12 adjacent in the thickness direction T. Thereby, the ratio of the volume occupied by the first reinforcing layer 17a in the region in which the plurality of first reinforcing layers 17a are provided can be set to be the first in the effective portion 10A in which the first and second internal electrodes 11 and 12 are provided. The ratio of the volume occupied by the second internal electrodes 11 and 12 is large.
As shown in FIG. 3, a plurality of second reinforcing layers 17b are formed in the second outer layer portion 10C. A plurality of second reinforcing layers 17b are formed along the longitudinal direction L and the width direction W. A plurality of second reinforcing layers 17b are laminated in the thickness direction T. The plurality of second reinforcing layers 17b are not formed at both end portions of the ceramic base 10 in the longitudinal direction L. The plurality of second reinforcing layers 17b are formed over the central portion excluding both end portions in the longitudinal direction L. A plurality of second reinforcing layers 17b are formed inside the ceramic base 10 and are not exposed from the surface of the ceramic base 10. In the present embodiment, the planar shape of the first reinforcing layer 17a and the planar shape of the second reinforcing layer 17b are substantially equal.
As shown in FIG. 3, a part of the plurality of second reinforcing layers 17b, specifically, the outer end portions of the plurality of second reinforcing layers 17b in the longitudinal direction L are in the thickness direction T and the first and second external electrodes 13, 14 The third part 13c, 14d is opposite. In other words, the outer end portions of the plurality of second reinforcing layers 17b in the longitudinal direction L face the third portions 13c and 14d of the first and second outer electrodes 13 and 14 in the thickness direction T.
The number of the second reinforcing layers 17b is not particularly limited. For example, the number of the first and second internal electrodes 11 and 12 can be 1.5 to 15 times. Specifically, the number of sheets of the second reinforcing layer 17b can be, for example, about 3 to 30 sheets. In the present embodiment, the case where a plurality of second reinforcing layers 17b are provided has been described. However, in the present embodiment, only one layer of the second reinforcing layer 17b may be provided.
The distance between the second reinforcing layers 17b adjacent in the thickness direction T is smaller than the distance between the first and second internal electrodes 11 and 12 adjacent to the thickness direction T. The distance between the second reinforcing layers 17b adjacent in the thickness direction T is preferably 0.125 to 0.5 times the distance between the first and second internal electrodes 11 and 12 adjacent in the thickness direction T. Thereby, the ratio of the volume occupied by the second reinforcing layer 17b in the region in which the plurality of second reinforcing layers 17b are provided can be set to be the first in the effective portion 10A in which the first and second internal electrodes 11 and 12 are provided. The ratio of the volume occupied by the second internal electrodes 11 and 12 is large.
In addition, the material of the first and second reinforcing layers 17a and 17b is not particularly limited as long as it is superior to the ceramic base 10 in ductility. The first and second reinforcing layers 17a and 17b can be formed, for example, of a metal such as Ni, Cu, Ag, Pd, or Au, an Ag-Pd alloy, or an alloy including one or more of these metals.
The thickness of each of the first and second reinforcing layers 17a and 17b can be, for example, about 0.3 μm to 2.0 μm. The thickness of each of the first and second reinforcing electrodes 17a and 17b may be equal to the thickness of each of the first and second internal electrodes 11 and 12, or may be smaller than the thickness of each of the first and second internal electrodes 11 and 12, respectively. The thickness of each of the first and second internal electrodes 11 and 12 may be larger. The thickness of each of the first and second reinforcing layers 17a and 17b is preferably equal to or greater than the thickness of each of the first and second internal electrodes 11 and 12. Thereby, the ratio of the volume occupied by the second reinforcing layer 17b in the region in which the plurality of second reinforcing layers 17b are provided can be made larger than the first in the effective portion 10A in which the first and second internal electrodes 11 and 12 are provided. The ratio of the volume occupied by the second internal electrodes 11 and 12 is large.
The length of the longitudinal direction L of the first and second reinforcing layers 17a and 17b, the sum of the lengths of the first internal electrode 11 and the longitudinal direction L of the first dummy electrode 18, and the second internal electrode 12 and the second dummy electrode 19 are preferable. The sum of the lengths of the length directions L is equal to each other. In this case, the type of the ceramic green sheet which is required to produce the ceramic electronic component 1 and has the conductive paste printed on its surface can be reduced. Therefore, the manufacture of the ceramic electronic component 1 becomes easy.
In the present embodiment, as shown in FIG. 3, the thickness T2 of both end portions of the ceramic base 10 in which the first and second reinforcing layers 17a and 17b are not provided in the longitudinal direction is the first and second in the thickness direction T. The thicknesses T1 of the portions of the ceramic base 10 facing the first and third portions 13a, 13c, 14a, and 14c of the external electrodes 13 and 14 and the first and second reinforcing layers 17a and 17b are small. Therefore, as shown in detail in Fig. 4, in the portion of the first main surface 10a of the ceramic base 10 where the first portions 13a and 14a of the first or second external electrodes 13 and 14 are provided, and the first reinforcing layer 17a. The end portions 10a1 and 10a2 that do not overlap in the longitudinal direction L are closer to the center in the thickness direction T than the portion overlapping the first reinforcing layer 17a. Further, among the second main faces 10b of the ceramic base 10, the portions of the third portions 13c and 14c where the first or second outer electrodes 13 and 14 are provided are not overlapped with the second reinforcing layer 17b in the longitudinal direction L. The portions 10b1 and 10b2 are closer to the center than the portion overlapping the second reinforcing layer 17b in the thickness direction T.
On the other hand, in the first portions 13a and 14a of the first and second outer electrodes 13 and 14, the outer end portion (the first or second end surface 10e of the longitudinal direction L of the first reinforcing layer 17a) is not provided. The thickness of the 10f side end portion is thicker than the thickness of the other portions. In the third portions 13c and 14c of the first and second outer electrodes 13 and 14, the outer end portions (the first or second end faces 10e and 10f in the longitudinal direction L of the second reinforcing layer 17b are not provided). The thickness of the side end portion is thicker than the thickness of the other portions.
Next, an example of a method of manufacturing the ceramic electronic component 1 of the present embodiment will be described.
First, a ceramic green sheet 20 (refer to FIG. 8) containing a ceramic material for constituting the ceramic base 10 is prepared. Next, as shown in FIG. 8, a conductive paste is applied onto the ceramic green sheet 20 to form a conductive pattern 21. Further, the formation of the conductive pattern can be performed, for example, by various printing methods such as screen printing. The conductive paste may contain a known binder or solvent in addition to the conductive fine particles.
In the present embodiment, the length of the first and second reinforcing layers 17a and 17b in the longitudinal direction L, the sum of the lengths of the first internal electrode 11 and the longitudinal direction L of the first dummy electrode 18, and the second internal electrodes 12 and The sum of the lengths of the longitudinal directions L of the dummy electrodes 19 is equal to each other. Therefore, the ceramic green sheet 20 for forming the first inner electrode 11 and the first dummy electrode 18, the ceramic green sheet 20 for forming the second inner electrode 12 and the second dummy electrode 19, and the first reinforcing layer 17a can be formed. The ceramic green sheet 20 and the ceramic green sheet 20 for forming the second reinforcing layer 17b are in common specifications. That is, it is sufficient to prepare a ceramic green sheet 20 on which a conductive paste is printed.
Next, as shown in FIGS. 10 to 12, the ceramic green sheets 20 on which the conductive patterns 21 are not formed and the ceramic green sheets 20 on which the conductive patterns 21 are formed are appropriately shifted in the longitudinal direction L, and they are laminated. The device is pressurized in the lamination direction by a device such as a pressure equalizer to produce the mother laminated body 22 shown in Fig. 9 .
Further, in the present embodiment, one ceramic green sheet 20 is located between the reinforcing layers 17a and 17b adjacent in the thickness direction T. On the other hand, the plurality of ceramic green sheets 20 are located between the first and second internal electrodes 11 and 12 adjacent in the thickness direction T.
Next, as shown in FIG. 9, the first conductive layer 15 constituting the first and second external electrodes 13 and 14 is formed on the mother laminated body 22 by an appropriate printing method such as a screen printing method. And a conductive pattern 23 having a shape corresponding to a portion of the third portion 13a, 14a, 13c, and 14c.
Next, the mother laminated body 22 is pressed again in the lamination direction. In this case, the thickness of the portion where the reinforcing layers 17a and 17b and the first and second internal electrodes 11 and 12 do not overlap is thinned, that is, as shown in FIG. 3, the thickness T2 is thinner than the thickness T1. Pressurize. For example, by providing an elastic body between the pressurizing metal mold and the main surface of the mother laminated body 22 and applying pressure, the reinforcing layers 17a and 17b and the first and second internal electrodes 11 and 12 can be effectively overlapped. The pressure is applied to the portion, and the relationship of the thickness described above can be easily achieved.
Next, a plurality of unprocessed ceramic laminates are produced from the mother laminate 22 by cutting the mother laminate 22 along the imaginary cutting line CL. In addition, the cutting of the mother laminate 22 can be performed by slicing or pressing cutting.
After the preparation of the unprocessed ceramic laminate, the corners of the unprocessed laminate and the angling portion may be chamfered or R-angled and the surface layer may be polished by cylindrical polishing or the like.
Thereafter, the conductive paste is applied to both end faces of the unprocessed ceramic laminate, for example, by dipping or the like. Here, the conductive layer 15 shown in FIG. 3 is formed by the applied conductive paste and the conductive pattern 23.
In addition, when a conductive paste is applied to both end faces of the unprocessed ceramic laminate by, for example, a dipping method, the conductive paste is also slightly wound around the first and second main faces and the first and second sides. . Therefore, the conductive paste layer which becomes the first conductivity 15 by the subsequent firing step is relatively thick at the end portions on the first or second end faces 10e and 10f side of the first and second main faces. Therefore, the outer end portion of the first conductive layer 15 in the longitudinal direction L is relatively thick, and as a result, the longitudinal direction L of the first and third portions 13a, 13c, 14a, and 14c of the first and second outer electrodes 13 and 14 is obtained. The thickness of the outer end portion is relatively thick. Further, after the conductive paste is applied to the first or second end faces 10e and 10f, the first or second end faces 10e and 10f are pressed against the stage to remove excess conductive paste, thereby forming the conductive paste. The thickness of the first conductive layer 15 on the first or second end faces 10e and 10f is reduced.
Next, baking of the unprocessed ceramic laminate is performed, and in the baking step, the conductive paste layer formed as described above is simultaneously fired (cofired) to form the conductive layer 15. Further, the firing temperature can be appropriately set depending on the type of the ceramic material to be used and the conductive paste. The firing temperature can be, for example, about 900 ° C to 1300 ° C.
Thereafter, polishing such as cylindrical polishing is performed as needed.
Finally, the conductive layer 16 is formed by electroplating, thereby completing the formation of the first and second external electrodes 13, 14. Further, in the present invention, the conductive layer 16 formed by plating is not necessary. For example, the first and second external electrodes 13 and 14 may be formed only by the conductive layer 15.
As described above, in the first embodiment, the first main surface 10a of the ceramic base 10 is provided with the first portions 13a and 14a of the first or second outer electrodes 13 and 14, and the first portion The end portions 10a1 and 10a2 in which the reinforcing layer 17a overlaps in the longitudinal direction L are closer to the center in the thickness direction T than the portion overlapping the first reinforcing layer 17a. Therefore, for example, when the ceramic electronic component 1 is placed on the side of the wiring board from the first main surface 10a, the ceramic electronic component 1 can be effectively prevented from being damaged even when stress is applied from the outside, and the ceramic electronic component 1 can be improved. Mechanical durability. The effects will be described in detail below.
In the ceramic electronic component 1, the first and second external electrodes 13 and 14 are formed on the first and second main faces 10a and 10b. Therefore, both end portions of the ceramic electronic component 1 in the longitudinal direction L protrude in the thickness direction T. Therefore, stress can be easily applied to both end portions of the ceramic electronic component 1 in the longitudinal direction L. When stress is applied to both end portions of the ceramic electronic component 1 in the longitudinal direction L, the thickness of the ceramic electronic component 1 is largely changed where the tips of the first and third portions 13a, 13c, 14a, and 14c are located. In the portions 10D and 10E (refer to FIG. 3), stress is concentrated, and cracks are easily generated in the portions 10D and 10E.
Here, for example, when the both ends of the ceramic electronic component 1 are the thickest, the distance between the end portion of the ceramic electronic component 1 serving as the fulcrum and the portions 10D and 10E serving as the action point becomes long. It is easy to apply a large stress to the portions 10D, 10E.
On the other hand, in the first main surface 10a of the ceramic base 10, the first portions 13a and 14a of the first or second outer electrodes 13 and 14 are provided in the first portion 13a and 14a. The end portions 10a1 and 10a2 in which the reinforcing layer 17a overlaps in the longitudinal direction L are closer to the center in the thickness direction T than the portion overlapping the first reinforcing layer 17a. Therefore, in the ceramic electronic component 1, the portion that protrudes most in the thickness direction T is closer to the center than the end portion. Therefore, the distance between the portions 10D and 10E which are the points of action and the fulcrum can be shortened. Therefore, it is difficult to apply a large stress to the portions 10D and 10E, so that damage of the ceramic base 10 in the portions 10D and 10E can be suppressed. As a result, higher mechanical durability can be achieved.
Further, in the present embodiment, the first and second reinforcing layers 17a and 17b are provided on the easily damaged portions 10D and 10E. Therefore, the mechanical strength of the portions 10D, 10E can be effectively improved.
In the present embodiment, the first and second reinforcing layers 17a and 17b are continuously formed over the center portion except for the both end portions of the ceramic base 10 in the longitudinal direction L. Therefore, the mechanical strength of the central portion in the longitudinal direction L of the ceramic base 10 which is easily damaged together with the portions 10D and 10E can be effectively improved.
Further, in the present embodiment, the thickness T2 of both end portions of the ceramic base 10 in which the first and second reinforcing layers 17a and 17b are not provided in the longitudinal direction is larger than the first and second external electrodes 13 in the thickness direction T, The thickness T1 of the portion of the ceramic base 10 facing the first and third portions 13a, 13c, 14a, 14c and the first and second reinforcing layers 17a, 17b of 14 is small. Further, the first and third portions 13a, 13c, 14a, and 14c of the first and second outer electrodes 13, 14 formed on the portion having a small thickness are formed relatively thick. Therefore, the surfaces of the first and third portions 13a, 13c, 14a, and 14c of the first and second outer electrodes 13 and 14 are substantially flat. Therefore, stress is not concentrated on a part of the first and third portions 13a, 13c, 14a, and 14c, and stress is applied as a whole, so that it is possible to effectively suppress application of a large stress to a part. Therefore, better mechanical durability can be achieved.
Further, in the present embodiment, the distance between the reinforcing layers 17a and 17b adjacent in the thickness direction is shorter than the distance between the first and second internal electrodes 11 and 12 adjacent in the thickness direction. Therefore, the volume ratio of the reinforcing layers 17a and 17b in the region where the reinforcing layers 17a and 17b are provided is large. Therefore, the mechanical strength of the region in which the reinforcing layers 17a and 17b are provided in the ceramic base 10 can be made higher. Therefore, the mechanical strength of the ceramic electronic component 1 can be further improved.
Further, since the distance between the reinforcing layers 17a and 17b adjacent in the thickness direction is short, the reinforcing layers 17a and 17b can be provided more. Therefore, the mechanical strength of the ceramic electronic component 1 can be further improved.
In addition, when the number of the internal electrodes 11 and 12 is large, the effect of improving the mechanical strength by the internal electrodes 11 and 12 is also large, and the thickness of the ceramic base 10 is also increased, so that it is easy to improve. The mechanical strength of the ceramic electronic component 1. On the other hand, when the number of the internal electrodes 11 and 12 is as small as 2 to 20, for example, the effect of improving the mechanical strength by the internal electrodes 11 and 12 is not obtained, and the thickness of the ceramic base 10 is small. Therefore, the problem of the mechanical strength of the ceramic electronic component 1 becomes remarkable. Therefore, as shown in the present embodiment, the technique of improving the mechanical durability of the ceramic electronic component 1 by providing the reinforcing layers 17a and 17b and lowering the end portion of the first main surface 10a in the longitudinal direction L is at the internal electrode. It is particularly effective when the number of layers of 11, 12 is as small as 2 to 20 pieces.
Next, other examples of preferred embodiments for carrying out the invention will be described. In the following description, components having functions that are substantially the same as those of the above-described first embodiment are denoted by the same reference numerals, and description thereof will be omitted.
Fig. 13 is a schematic cross-sectional view showing a ceramic electronic component of a second embodiment.
In the present embodiment, as shown in FIG. 13, at least a part of the first and third portions 13a, 13c, 14a, and 14c of the first and second external electrodes 13 and 14 are buried in the first or second main surface 10a. , 10b. Even in this case, as in the first embodiment described above, the effect of improving the mechanical durability of the ceramic electronic component 1 can be obtained.
In the ceramic electronic component of the present embodiment, for example, the conductive pattern 23 having a shape corresponding to the portion constituting the first and third portions 13a, 13c, 14a, and 14c is printed on the main surface of the mother laminated body 22, and then the laminated layer is formed in the laminated direction. When the mother laminated body 22 is pressurized, the state of being buried as described above can be achieved by applying pressure with a stronger force.
Fig. 14 is a schematic cross-sectional view showing a ceramic electronic component of a third embodiment.
In the first embodiment, the first and second outer electrodes 13 and 14 are formed on the first and second main faces 10a and 10b, respectively. However, the present invention is not limited to such a configuration. In the present invention, at least one external electrode may be formed on the first main surface 10a.
For example, as shown in FIG. 14, the first and second outer electrodes 13 and 14 may be formed to cover the first or second end faces 10e and 10f and the first main face 10a. In other words, the first and second external electrodes 13 and 14 are not limited to this shape as long as they have the first portions 13a and 14a and are electrically connected to the first or second internal electrodes 11 and 12.
Further, in the present embodiment, the second reinforcing layer 17b may be provided in addition to the first reinforcing layer 17a, and the first reinforcing layer 17a may be provided only on the side where the first portions 13a and 14a are provided. To effectively improve the mechanical durability of the ceramic electronic component 1. Further, by not forming the third portions 13c and 14c and the second reinforcing layer 17b, it is possible to further reduce the thickness of the ceramic electronic component 1.
The ceramic electronic component 1 of the first embodiment described above was produced by the production method described in the first embodiment. In addition, the detailed conditions are as follows. As a result of observing the cross section of the ceramic electronic component 1 obtained in the present example with an electron microscope, it was confirmed that both end portions of the first and second main faces 10a and 10b can be made low.
(Conditions of the examples)
Design capacitance: 1nF
Ceramic material used in the fabrication of ceramic substrates: dielectric ceramics based on BaTiO 3
Thickness of ceramic layer (after firing): 1.35 μm
Internal electrodes 11, 12, virtual electrodes 18, 19 material: Ni
Internal electrodes 11, 12, thickness of dummy electrodes 18, 19 (after firing): 0.75 μm
Distance between internal electrodes 11, 12: 9.45 μm
Number of internal electrodes 11, 12: 4
Number of sheets of the first and second reinforcing layers 17a and 17b: 20 pieces
Material of the first and second reinforcing layers 17a and 17b: Ni
Reinforcing interlayer distance in each of the first and second reinforcing layers 17a and 17b: 1.35 μm
The highest temperature for firing: 1200 ° C
Burning atmosphere: reducing atmosphere
Material of the first conductive layer 15: Ni
Material of the second conductive layer 16: Cu
A ceramic electronic component was produced in the same manner as in the above-described embodiment except that the first and second reinforcing layers 17a and 17b were not provided.
Fig. 15 is a schematic cross-sectional view showing a ceramic electronic component of Comparative Example 2. As shown in Fig. 15, a ceramic electronic component was produced in the same manner as in the above-described embodiment except that the reinforcing layers 17a1, 17a2, 18a1, and 18a2 were formed to extend from the first or second end faces 10e and 10f toward the center. The total length of the reinforcing layers 17a1, 17a2, the total length of the reinforcing layers 18a1, 18a2, and the lengths of the reinforcing layers 17a, 17b in the embodiment are equal.
As a result of observing the cross section of the ceramic electronic component obtained in the comparative example with an electron microscope, it was confirmed that both end portions of the first and second main faces 10a and 10b were not flat and flat.
In addition, in FIG. 15, for the convenience of description, the components having the functions substantially the same as those of the above-described first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.
Each sample of the ceramic electronic component manufactured in the above Examples and Comparative Examples 1 and 2 was pressed against an iron plate using a manufacturing apparatus YG100B manufactured by YAMAHA Engine Co., Ltd., and then an optical microscope was used to confirm whether or not the sample was produced on the sample. broken. In addition, tests of 10 samples were carried out under respective conditions of extrusion. The result is shown in FIG.
As shown in Fig. 16, in the embodiment in which the reinforcing layers 17a and 17b were provided, the comparative example 2 in which the reinforcing layers were not provided, and the comparative example 2 in which the reinforcing layers 17a1, 17a2, 18a1, and 18a2 were provided, the incidence of the crushing was small.
1. . . Ceramic electronic parts
10. . . Ceramic substrate
10A. . . Effective part
10B. . . First outer layer
10C. . . Second outer layer
10a. . . First main face
10b. . . Second main face
10c. . . First side
10d. . . Second side
10e. . . First end face
10f. . . Second end face
10g. . . Ceramic layer
11. . . First internal electrode
12‧‧‧2nd internal electrode
13‧‧‧1st external electrode
13a‧‧‧Part 1
13b‧‧‧Part 2
13c‧‧‧Part 3
14‧‧‧2nd external electrode
14a‧‧‧Part 1
14b‧‧‧Part 2
14c‧‧‧Part 3
15‧‧‧1st conductive layer
16‧‧‧2nd conductive layer
17a‧‧‧1st reinforcing layer
17b‧‧‧2nd reinforcing layer
18‧‧‧1st virtual electrode
19‧‧‧2nd virtual electrode
20‧‧‧Ceramic blanks
21‧‧‧ conductive pattern
22‧‧‧ mother laminate
23‧‧‧ conductive pattern
Fig. 1 is a schematic perspective view of a ceramic electronic component according to a first embodiment.
Fig. 2 is a schematic side view showing a ceramic electronic component of the first embodiment.
Fig. 4 is a schematic cross-sectional view showing a part of the ceramic electronic component of the first embodiment in an enlarged manner.
Fig. 5 is a schematic cross-sectional view showing a line V-V of Fig. 3.
Fig. 6 is a schematic cross-sectional view taken along line VI-VI of Fig. 3.
Fig. 7 is a schematic cross-sectional view taken along line VII-VII of Fig. 3.
Fig. 8 is a schematic plan view of a ceramic green sheet on which a conductive pattern is formed.
Fig. 9 is a schematic plan view of a mother laminated body.
FIG. 10 is a schematic plan view for explaining a position of a cutting line in a ceramic green sheet for forming a first internal electrode and a first dummy electrode of a mother laminated body.
FIG. 11 is a schematic plan view showing the position of a dicing line in the ceramic green sheet for forming the second internal electrode and the second dummy electrode of the mother laminated body.
Fig. 12 is a schematic plan view for explaining a position of a cutting line in a ceramic green sheet for forming a reinforcing layer of a mother laminated body.
Fig. 15 is a schematic cross-sectional view showing a ceramic electronic component of Comparative Example 2.
Fig. 16 is a graph showing the number of occurrences of fracture in the ceramic electronic parts of the examples and the comparative examples 1 and 2.
10a1, 10a2, 10b1, 10b2. . . Ends
12. . . Second internal electrode
13. . . First external electrode
13a. . . part 1
13b. . . part 2
13c. . . Part 3
14. . . Second external electrode
14a. . . part 1
14b. . . part 2
14c. . . Part 3
16. . . Second conductive layer
17a. . . 1st reinforcing layer
17b. . . 2nd reinforcing layer
18. . . First virtual electrode
19. . . Second virtual electrode
A ceramic electronic component comprising: a rectangular parallelepiped ceramic substrate having a first main surface and a second main surface extending in a longitudinal direction and a width direction, and first and second sides extending in a longitudinal direction and a thickness direction And a first end surface and a second end surface extending in the width direction and the thickness direction; the first inner electrode and the second inner electrode are formed inside the ceramic base body and extend in the longitudinal direction and the width direction in the thickness direction Opposite to each other; a first external electrode formed on the ceramic substrate and electrically connected to the first internal electrode; and a second external electrode formed on the ceramic substrate and electrically connected to the second internal electrode; Each of the first outer electrode and the second outer electrode has a first conductive layer formed on the first end surface or the second end surface and an end portion of the first main surface in the longitudinal direction; and the first conductive layer is covered a second conductive layer formed by a conductive layer; the first conductive layer and the second conductive layer respectively have a first portion located at an end portion of the first main surface in a longitudinal direction, and the first end surface or the first end surface Part 2 on the second end face; the pottery The base body includes: an effective portion facing the first inner electrode and the second inner electrode in a thickness direction; a first outer layer portion closer to the first main surface than the effective portion; and closer to the effective portion 2 second outer portion on the main surface side; The ceramic electronic component further includes a first reinforcing layer formed in the first outer layer portion along the longitudinal direction and the width direction, and a portion of the first reinforcing layer and the first external electrode in the thickness direction The first portion of the second external electrode faces the first reinforcing layer, and the first reinforcing layer is not exposed from any of the first end surface and the second end surface; and the first conductive layer is provided on the first main surface In the portion of the first portion, the portion that does not face the first reinforcing layer is closer to the center in the thickness direction than the portion that faces the first reinforcing layer.
The ceramic electronic component according to claim 1, wherein a thickness ratio of a portion not facing the first reinforcing layer in the first portion of each of the first external electrode and the second external electrode The thickness of the portion opposite to the first reinforcing layer is thick.
The ceramic electronic component according to the second aspect of the invention, wherein the first external electrode and the second external electrode have a first end surface or the second end surface and a longitudinal direction of the first main surface. a first conductive layer on the end portion; and a second conductive layer formed to cover the first conductive layer; and the first conductive layer in each of the first external electrode and the second external electrode In the portion, the thickness of the portion not opposed to the first reinforcing layer is thicker than the thickness of the portion facing the first reinforcing layer.
Such as the ceramic electronic zero of any one of the patent scopes 1 to 3 Further, each of the first outer electrode and the second outer electrode further has a third portion located at an end portion of the second main surface in the longitudinal direction; the ceramic electronic component further includes a second reinforcing layer, and the second portion The reinforcing layer is formed along the longitudinal direction and the width direction of the second outer layer portion, and a portion of the second reinforcing layer faces the first external electrode and the third portion of the second external electrode in the thickness direction; (2) the reinforcing layer is not exposed from any of the first end surface and the second end surface; and the portion of the second main surface on which the first external electrode or the third external electrode is provided is not The portion facing the second reinforcing layer is closer to the center in the thickness direction than the portion facing the second reinforcing layer.
The ceramic electronic component according to claim 4, wherein the first external electrode and the second external electrode further have a third portion located at an end portion of the second main surface in a longitudinal direction; the ceramic electronic component Further, the second reinforcing layer is formed in the second outer layer portion along the longitudinal direction and the width direction, and a part of the second reinforcing layer and the first external electrode and the second external electrode are formed in the thickness direction. The third reinforcing layer is not exposed from any of the first end surface and the second end surface; and the first outer electrode or the second outer electrode is provided on the second main surface In the portion of the third portion, the portion that does not face the second reinforcing layer is closer to the center in the thickness direction than the portion that faces the second reinforcing layer. position.
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