Multilayer ceramic capacitor
阅读说明:本技术 多层陶瓷电容器 (Multilayer ceramic capacitor ) 是由 李种晧 曺义铉 李长烈 朴明俊 具贤熙 于 2018-12-19 设计创作,主要内容包括:本公开提供一种多层陶瓷电容器。所述陶瓷电容器包括主体和位于所述主体上的外电极。所述主体包括介电层和内电极。所述外电极包括:电极层,连接到所述内电极;第一镀覆部,位于所述电极层上;以及第二镀覆部,位于所述第一镀覆部上。所述第一镀覆部包括多个镀层,所述多个镀层中交替地堆叠有锡(Sn)镀层和镍(Ni)镀层。(The present disclosure provides a multilayer ceramic capacitor. The ceramic capacitor includes a body and an external electrode on the body. The body includes a dielectric layer and an inner electrode. The outer electrode includes: an electrode layer connected to the internal electrode; a first plating section on the electrode layer; and a second plating section located on the first plating section. The first plating section includes a plurality of plating layers in which tin (Sn) plating layers and nickel (Ni) plating layers are alternately stacked.)
1. A multilayer ceramic capacitor comprising:
a body including a dielectric layer and an internal electrode; and
an outer electrode on the body,
wherein the outer electrode includes: an electrode layer connected to the internal electrode; a first plating section on the electrode layer; and a second plating section located on the first plating section and having a first plating thickness
Wherein the first plating part includes a plurality of plating layers including a plurality of tin plating layers and one or more nickel plating layers, the tin plating layers being alternately stacked with the nickel plating layers.
2. The multilayer ceramic capacitor according to claim 1, wherein a first plating layer of the plurality of plating layers of the first plating part is in contact with the electrode layer and is one of the plurality of tin plating layers.
3. The multilayer ceramic capacitor according to claim 1, wherein the first plating part comprises a first tin plating layer, a nickel plating layer, and a second tin plating layer in this order, the first tin plating layer being located on the electrode layer.
4. The multilayer ceramic capacitor of claim 1, wherein the first thickness of the first plating portion is less than the second thickness of the second plating portion.
5. The multilayer ceramic capacitor of claim 1, wherein the first thickness of the first plating part is 1/2 or less of the second thickness of the second plating part.
6. The multilayer ceramic capacitor according to claim 1, wherein the thickness of the tin plating layer of the first plating part is in the range of 0.1 μm to 1 μm.
7. The multilayer ceramic capacitor according to claim 1, wherein the second plating part comprises a nickel plating layer and a tin plating layer in this order, the nickel plating layer being located on the first plating part.
8. The multilayer ceramic capacitor according to claim 7, wherein a third thickness of the nickel plating layer of the second plating part is in a range of 1 μm to 10 μm, and a fourth thickness of the tin plating layer of the second plating part is in a range of 1 μm to 10 μm.
9. The multilayer ceramic capacitor of claim 1, wherein the electrode layer is a sintered electrode comprising a conductive metal and glass.
10. The multilayer ceramic capacitor as set forth in claim 1,
wherein the internal electrodes include first and second internal electrodes alternately stacked with a dielectric layer interposed therebetween, and
wherein the external electrodes include first and second external electrodes connected to the first and second internal electrodes, respectively.
11. A multilayer ceramic capacitor comprising:
a body including a dielectric layer and an internal electrode; and
an outer electrode on the body,
wherein the outer electrode includes: an electrode layer contacting the internal electrode; a first plating section on the electrode layer; and a second plating section located on the first plating section,
wherein the first plating section includes a plurality of plating layers including a plurality of tin plating layers and one or more nickel plating layers, the tin plating layers and the nickel plating layers being alternately stacked, and
wherein a first tin-nickel intermetallic compound layer is located at a respective interface region between the tin plating layer and the nickel plating layer of the first plating section.
12. The multilayer ceramic capacitor of claim 11, wherein the first thickness of the first plating portion is less than the second thickness of the second plating portion.
13. The multilayer ceramic capacitor of claim 11, wherein the first thickness of the first plating part is 1/2 or less of the second thickness of the second plating part.
14. The multilayer ceramic capacitor of claim 11, wherein the first tin-nickel intermetallic compound layers each comprise 10 to 90 wt% tin and 10 to 90 wt% nickel.
15. The multilayer ceramic capacitor as set forth in claim 11,
wherein the second plating part comprises a nickel plating layer, a second tin-nickel intermetallic compound layer and a tin plating layer in this order, the nickel plating layer is located on the first plating part, and
wherein a third tin-nickel intermetallic compound layer is located at an interface region between the first plating section and the second plating section.
16. A multilayer ceramic capacitor comprising:
a body including a dielectric layer and an internal electrode; and
an outer electrode on the body, the outer electrode comprising: an electrode layer in contact with the internal electrode; a first plating section that is located on the electrode layer and includes tin, nickel, and a first tin-nickel intermetallic compound; and a second plating section located on the first plating section.
17. The multilayer ceramic capacitor according to claim 16, wherein the first plating part includes 10 to 90 wt% of tin and 10 to 90 wt% of nickel.
18. The multilayer ceramic capacitor of claim 16, wherein the second plating part comprises a nickel plating layer and a tin plating layer in this order, the nickel plating layer being on the first plating part.
19. The multilayer ceramic capacitor as set forth in claim 18,
wherein a second tin-nickel intermetallic compound layer is located at a first interface region between the tin plating layer and the nickel plating layer of the second plating section, and
wherein a third tin-nickel intermetallic compound layer is located at a second interface region between the first plating section and the second plating section.
20. A multilayer ceramic capacitor comprising:
a body including a plurality of first internal electrodes extending to a first side surface of the body parallel to a stacking direction and alternately stacked with the plurality of second internal electrodes extending to a second side surface of the body parallel to the stacking direction and opposite to the first side surface, and a dielectric layer interposed between the first and second internal electrodes;
a first external electrode electrically connected to the plurality of first internal electrodes and including a first electrode layer on the first side surface of the body, a first internal plating layer on the first electrode layer, and a first external plating layer on the first internal plating layer; and
a second external electrode electrically connected to the plurality of second internal electrodes and including a second electrode layer on the second side surface of the body, a second internal plating layer on the second electrode layer, and a second external plating layer on the second internal plating layer,
wherein the first and second inner plating layers each include a first tin layer on the first and second electrode layers, a first nickel layer on the first tin layer, and a second tin layer on the first nickel layer, and
wherein the first outer plating layer and the second outer plating layer each comprise a second nickel layer on the first inner plating layer and the second inner plating layer and a third tin layer on the second nickel layer.
21. The multilayer ceramic capacitor as set forth in claim 20,
wherein a first thickness of the first inner plating layer is less than or equal to half of a second thickness of the first outer plating layer, a first thickness of the second inner plating layer is less than or equal to half of a second thickness of the second outer plating layer, and
the first and second tin layers of the first and second inner plating layers each have a thickness in a range of 0.1 to 1 μm.
22. The multilayer ceramic capacitor of claim 20, wherein the first and second inner plating layers further comprise one or more tin layers other than the first and second tin layers and one or more nickel layers other than the first nickel layer, tin layers being alternately stacked with nickel layers.
23. The multilayer ceramic capacitor as set forth in claim 20,
wherein each of the first and second inner plating layers further includes a first tin-nickel intermetallic compound layer between the first tin layer and the first nickel layer and a second tin-nickel intermetallic compound layer between the first nickel layer and the second tin layer,
wherein the first outer plating layer and the second outer plating layer each further include a third tin-nickel intermetallic layer between the second nickel layer and the third tin layer, and
wherein the first outer electrode and the second outer electrode each further include a fourth tin-nickel intermetallic compound layer between the first inner plating layer and the first outer plating layer and between the second inner plating layer and the second outer plating layer.
24. A multilayer ceramic capacitor comprising:
a body including a plurality of first internal electrodes extending to a first side surface of the body parallel to a stacking direction and alternately stacked with the plurality of second internal electrodes extending to a second side surface of the body parallel to the stacking direction and opposite to the first side surface, and a dielectric layer interposed between the first and second internal electrodes;
a first external electrode electrically connected to the plurality of first internal electrodes and including a first electrode layer on the first side surface of the body, a first tin-nickel intermetallic compound layer on the first electrode layer, and a first external plating layer on the first tin-nickel intermetallic compound layer; and
a second external electrode electrically connected to the plurality of second internal electrodes and including a second electrode layer on the second side surface of the body, a second tin-nickel intermetallic compound layer on the second electrode layer, and a second external plating layer on the second tin-nickel intermetallic compound layer,
wherein the first outer plating layer and the second outer plating layer each include a second nickel layer on the first tin-nickel intermetallic compound layer and the second tin-nickel intermetallic compound layer and a third tin layer on the second nickel layer.
25. A multilayer ceramic capacitor comprising:
a main body; and
an outer electrode on the body, comprising: a first electrode layer on a surface of the body and including a first conductive metal; a first plating layer on the first electrode layer and including a second conductive metal and a third conductive metal; and a second plating layer on the first plating layer and including a first layer of the third conductive metal and a second layer of the second conductive metal,
wherein the first conductive metal, the second conductive metal and the third conductive metal are each different materials, and
wherein the second conductive metal is tin.
26. The multilayer ceramic capacitor of claim 25, wherein the first conductive metal is copper and the third conductive metal is nickel.
27. The multilayer ceramic capacitor according to claim 26, wherein the first plating layer including the second conductive metal and the third conductive metal further includes an intermetallic compound layer in which the second conductive metal and the third conductive metal are mixed.
Technical Field
The present disclosure relates to a multilayer ceramic capacitor.
Background
Multilayer ceramic capacitors (MLCCs) are important chip components used in industrial fields such as communications, computing, electronics manufacturing, vehicle manufacturing, and others. The multilayer ceramic capacitor is small in size, can secure a high capacity, and can be easily mounted. Multilayer ceramic capacitors are also core passive components used in various electronic devices, such as cellular phones, computers, digital TVs, etc.
Recently, demands for mobile devices, wearable devices, and the like have increased, and it is important to ensure moisture-proof reliability of multilayer ceramic capacitors to allow their use in various climates and environments.
In general, moisture-proof reliability is secured by forming Ni plating and Sn plating on electrode layers of external electrodes of a multilayer ceramic capacitor. However, when the general plating method is used, there is a problem of discontinuity of plating such as due to discontinuity of an electrode layer, glass beading phenomenon in which glass included in the electrode layer protrudes outward, and the like. The portion where the plating layer is not formed becomes a path for moisture permeation, which may reduce the reliability of moisture resistance.
Disclosure of Invention
An aspect of the present disclosure provides a multilayer ceramic capacitor having excellent moisture-proof reliability by preventing plating discontinuity.
According to an aspect of the present disclosure, a multilayer ceramic capacitor includes a body and external electrodes on the body. The body includes a dielectric layer and an inner electrode. The outer electrode includes: an electrode layer connected to the internal electrode; a first plating section on the electrode layer; and a second plating section located on the first plating section. The first plating section includes a plurality of plating layers in which tin (Sn) plating layers and nickel (Ni) plating layers are alternately stacked.
According to another aspect of the present disclosure, a multilayer ceramic capacitor includes a body and external electrodes on the body. The body includes a dielectric layer and an inner electrode. The outer electrode includes: an electrode layer contacting the internal electrode; a first plating section on the electrode layer; and a second plating section located on the first plating section. The first plating part includes a plurality of plating layers including tin (Sn) plating layers and nickel (Ni) plating layers that are alternately stacked. A tin-nickel (Sn-Ni) intermetallic compound layer is located at an interface region between the tin (Sn) plating layer and the nickel (Ni) plating layer of the first plating part.
According to another aspect of the present disclosure, a multilayer ceramic capacitor includes a body and external electrodes on the body. The body includes a dielectric layer and an inner electrode. The outer electrode includes an electrode layer in contact with the inner electrode. The first plating part is located on the electrode layer and includes tin (Sn), nickel (Ni), and a tin-nickel (Sn-Ni) intermetallic compound. The second plating section is located on the first plating section.
According to another aspect of the present disclosure, a multilayer ceramic capacitor includes: a body including a plurality of first internal electrodes extending to a first side surface of the body parallel to a stacking direction and alternately stacked with the plurality of second internal electrodes extending to a second side surface of the body parallel to the stacking direction and opposite to the first side surface, and a dielectric layer interposed between the first and second internal electrodes; a first external electrode electrically connected to the plurality of first internal electrodes and including a first electrode layer on the first side surface of the body, a first internal plating layer on the first electrode layer, and a first external plating layer on the first internal plating layer; and a second outer electrode electrically connected to the plurality of second inner electrodes and including a second electrode layer on the second side surface of the body, a second inner plating layer on the second electrode layer, and a second outer plating layer on the second inner plating layer, wherein the first inner plating layer and the second inner plating layer each include a first tin layer on the first electrode layer and the second electrode layer, a first nickel layer on the first tin layer, and a second tin layer on the first nickel layer, wherein the first outer plating layer and the second outer plating layer each include a second tin layer on the first inner plating layer and the second nickel layer, and a third tin layer on the second nickel layer.
According to another aspect of the present disclosure, a multilayer ceramic capacitor includes: a body including a plurality of first internal electrodes extending to a first side surface of the body parallel to a stacking direction and alternately stacked with the plurality of second internal electrodes extending to a second side surface of the body parallel to the stacking direction and opposite to the first side surface, and a dielectric layer interposed between the first and second internal electrodes; a first external electrode electrically connected to the plurality of first internal electrodes and including a first electrode layer on the first side surface of the body, a first tin-nickel intermetallic compound layer on the first electrode layer, and a first external plating layer on the first tin-nickel intermetallic compound layer; and a second outer electrode electrically connected to the plurality of second inner electrodes and including a second electrode layer on the second side surface of the body, a second tin-nickel intermetallic compound layer on the second electrode layer, and a second outer plating layer on the second tin-nickel intermetallic compound layer, wherein the first outer plating layer and the second outer plating layer each include a second nickel layer on the first tin-nickel intermetallic compound layer and the second tin-nickel intermetallic compound layer and a third tin layer on the second nickel layer.
According to another aspect of the present disclosure, a multilayer ceramic capacitor includes: a main body; and an outer electrode on the body, comprising: a first electrode layer on a surface of the body and including a first conductive metal; a first plating layer on the first electrode layer and including a second conductive metal and a third conductive metal; and a second plating layer on the first plating layer and including a first layer of the third conductive metal and a second layer of the second conductive metal, wherein the first conductive metal, the second conductive metal, and the third conductive metal are different materials, respectively, and wherein the second conductive metal is tin.
Drawings
The above and other aspects, features and advantages of the present disclosure will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:
fig. 1 is a schematic perspective view of a multilayer ceramic capacitor according to an exemplary embodiment in the present disclosure;
FIG. 2 is a sectional view taken along line I-I' in FIG. 1;
FIGS. 3A and 3B are plan views of ceramic green sheets on which internal electrodes are printed to manufacture a main body of a multilayer ceramic capacitor;
fig. 4 is an enlarged view of a portion a in fig. 2 according to a first exemplary embodiment in the present disclosure;
fig. 5 is an enlarged view of a portion a in fig. 2 according to a second exemplary embodiment in the present disclosure;
fig. 6 is an enlarged view of a portion a in fig. 2 according to a third exemplary embodiment in the present disclosure; and
fig. 7 is an enlarged view of a portion a in fig. 2 according to a fourth exemplary embodiment in the present disclosure.
Detailed Description
Hereinafter, embodiments of the present disclosure will be described as follows with reference to the accompanying drawings.
This disclosure may, however, be embodied in many different forms and should not be construed as limited to the specific embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. Accordingly, the shapes and sizes of elements may be exaggerated for clarity of description. Further, elements having the same function within the scope of the same concept shown in the drawings of each exemplary embodiment will be described using the same reference numerals.
Fig. 1 is a schematic perspective view of a multilayer ceramic capacitor according to first to fourth exemplary embodiments. Fig. 2 is a sectional view taken along line I-I' in fig. 1. Fig. 3A and 3B are plan views of ceramic green sheets on which internal electrodes are printed to manufacture a main body of a multilayer ceramic capacitor.
Referring to fig. 1 to 3B, a multilayer
The
In an exemplary embodiment, the
The
For clarity of description of exemplary embodiments, in the drawings, the directions of the body may be discussed with respect to a first (length) direction (shown as the "X" direction), a second (width) direction (shown as the "Y" direction), and a third (thickness or stack) direction (shown as the "Z" direction).
The surfaces of the
The active area may be formed in a structure in which a plurality of first internal electrodes and a plurality of second internal electrodes are alternately stacked with a dielectric layer interposed therebetween. Referring to fig. 3A and 3B, the
The plurality of
The material of the
The thickness of each of the
The first
The first and second
The first
When a voltage is applied to the first and second
The thicknesses of the first and second
The conductive metal included in the first and second
The upper and
The upper and
The first
The first and second
The electrode layers 131 and 141 may mechanically connect the
The method of forming the electrode layers 131 and 141 is not particularly limited. The electrode layers 131 and 141 may be sintered electrodes formed by using a paste including a conductive metal and glass, or may be resin electrodes formed by using a paste including a conductive metal and a base resin. The electrode layers 131 and 141 may also be formed by an electroless plating method, a sputtering process, or an atomic layer deposition method.
When the electrode layers 131 and 141 are sintered electrodes including a conductive metal and glass, if a general plating method is used, it is highly likely that plating discontinuity occurs due to discontinuity of the electrode layers, a beading phenomenon of glass included in the electrode layers protruding outward, or the like. Therefore, when the electrode layer is a sintered electrode, the moisture-proof reliability effect may be significant according to the present disclosure described below.
The sintered electrode including the conductive metal and the glass may be formed by applying a paste including the conductive metal and the glass to be sintered.
Glass may be used to mechanically bond the
Fig. 4, 5, 6, and 7 are enlarged views of a portion a in fig. 2 according to the first exemplary embodiment, the second exemplary embodiment, the third exemplary embodiment, and the fourth exemplary embodiment, respectively.
The portion a is a portion of the first
In the following description, the first plating section and the second plating section according to the first exemplary embodiment and the second exemplary embodiment will be described in more detail with reference to fig. 4 and 5.
Referring to fig. 4, the
As shown in the
The conventional plating layer may have a problem of discontinuous plating due to discontinuity of the electrode layer or beading phenomenon of glass included in the electrode layer protruding outward. The area of the electrode layer not covered by plating becomes a path for moisture permeation, which may deteriorate the moisture-proof reliability. Plating discontinuity may occur because Sn grows in the horizontal direction when plating Sn and Ni grows in the vertical direction when plating Ni. Since Sn generally grows parallel to the surface of the body such that Sn covers the surface of the body, plating discontinuity generally does not occur when plating Sn. However, when Ni is plated, Ni generally grows perpendicular to the surface of the body, and plating discontinuity may easily occur. When there is a large gap without plating Ni, plating of Sn may be discontinuous even if Sn grows in the horizontal direction.
However, in the present disclosure, the
An alternative to the Sn plating layer being formed as a pre-plating layer is considered. In this case, the first plating part may be formed as Sn plating, and the second plating part is a conventional plating formed on the first plating part. However, if the first plating section is simply Sn plating as a pre-plating layer, then the Sn plating layer may need to reach a certain minimum thickness. However, increasing the thickness of the Sn plating layer may decrease the adhesion (coherence) between the first plating part and the electrode layer, and may also cause Sn to be accumulated in a reflow process when the multilayer ceramic capacitor is bonded to a substrate. Reflow may refer to a process of melting solder by heat treatment to form an electrical contact between the substrate and the multilayer ceramic capacitor so that the multilayer ceramic capacitor may be stably bonded to the substrate.
In the present disclosure, the
The plating layer of the first plating section in contact with the electrode layer may be Sn plating. As the Sn plating layer grows on the electrode layer in the horizontal direction, the electrode layer may be plated without discontinuity.
As shown in fig. 4, the
As shown in fig. 5, the first plating part 132' may include a first
The
Preferably, the thickness of the
The thickness of the
If the thickness of the
When the thickness of the
The thickness of the
Table 1 below shows experimental data on plating discontinuity and Sn plating aggregation based on the thicknesses of the Sn plating layer and the Ni plating layer.
A ceramic body is prepared. Paste including Cu powder and glass is applied to both sides of the ceramic main body in the length direction and sintered, and an electrode layer is formed. The first plating section is formed by sequentially performing a first Sn plating process, a Ni plating process, and a second Sn plating process on the electrode layer such that the first Sn plating layer, the Ni plating layer, and the second Sn plating layer obtain the thicknesses shown in table 1. The second plating section was formed by plating Ni and Sn in this order on the first plating section to form Ni plating and Sn plating having thicknesses shown in table 1. Thus, a multilayer ceramic capacitor was produced. In the case of experiment No. 1, only the second plating section was formed on the electrode layer without forming the first plating section.
After completion of plating based on 100 samples, the incidence of plating discontinuity was measured by analyzing the sections of the first plating section and the second plating section and determining whether or not a discontinuity occurred in the Ni plating layer.
After reflow based on 100 samples, the defect rate of Sn plating aggregation was measured by determining whether or not holes were formed in the Sn plating layer of the first plating section.
[ Table 1]
In the case of experiment No. 1, since the first plated portion was not formed, the incidence of plating discontinuity was 40%. Accordingly, the reliability against moisture is lowered.
Since the thickness of the first Sn plating layer exceeded 1 μm in experiment No. 2 and the thickness of the second Sn plating layer exceeded 1 μm in experiment No. 5, Sn aggregation occurred during reflow.
However, since the thicknesses of the first Sn plating layer and the second Sn plating layer were in the range of 0.1 μm to 1 μm in test nos. 3 and 4, no Sn aggregation was detected.
As described above, the
The thickness of the
The third exemplary embodiment and the fourth exemplary embodiment will be described in more detail with reference to fig. 6 and 7. A description overlapping with the aforementioned description will be omitted.
Fig. 6 is an enlarged view of a portion a in fig. 2 according to the third exemplary embodiment.
Referring to fig. 6, according to the third exemplary embodiment, the
The Sn — Ni
The Sn-
When the
Fig. 7 is an enlarged view of a portion a in fig. 2 according to the fourth exemplary embodiment.
Referring to fig. 7, according to the fourth exemplary embodiment, the first plating part 132' ″ may include Sn, Ni, and a Sn — Ni intermetallic compound.
According to the fourth exemplary embodiment, the first plating part 132' ″ may be plated such that Sn plating layers and Ni plating layers are alternately disposed, and may be formed in such a manner as to be interdiffused by heat treatment using Sn and Ni before forming the second plating part, with the boundary of each plating layer being integrated, making it difficult to recognize the boundary, and mixing Sn, Ni, and a Sn — Ni intermetallic compound. In this case, the first plating part 132' ″ may be referred to as a Sn — Ni intermetallic compound layer.
According to the fourth exemplary embodiment, the
According to the fourth exemplary embodiment, as in the second plating section of the third exemplary embodiment, the second plating section may be formed such that a Sn-Ni intermetallic compound layer is formed at an interface region between the Sn plating layer and the Ni plating layer of the second plating section, and such that a Sn-Ni intermetallic compound layer is formed at an interface region between the first plating section and the second plating section.
Although it is shown that the number of Sn plating layers is greater than the number of Ni plating layers in the first plating parts of various exemplary embodiments of the present disclosure, it is not limited thereto, and the number of Sn plating layers may be equal to or less than the number of Ni plating layers as long as Sn plating layers and Ni plating layers are alternately stacked.
As set forth above, according to the exemplary embodiments, by providing the first plating part including a plurality of plating layers between the electrode layer and the second plating part, plating discontinuity can be prevented, and accordingly, a multilayer ceramic capacitor having excellent moisture-proof reliability can be provided.
While exemplary embodiments have been shown and described above, it will be apparent to those skilled in the art that modifications and variations can be made without departing from the scope of the invention as defined by the appended claims.
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