U.S. patent application number 16/275785 was filed with the patent office on 2020-05-21 for dielectric composition and capacitor component using the same.
The applicant listed for this patent is SAMSUNG ELECTRO-MECHANICS CO., LTD.. Invention is credited to Jin Sung CHUN, Hae Suk CHUNG, Byung Sung KANG, Seul Gi KIM, Hyo Kyong SEO.
Application Number | 20200161048 16/275785 |
Document ID | / |
Family ID | 68420757 |
Filed Date | 2020-05-21 |
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United States Patent
Application |
20200161048 |
Kind Code |
A1 |
CHUN; Jin Sung ; et
al. |
May 21, 2020 |
DIELECTRIC COMPOSITION AND CAPACITOR COMPONENT USING THE SAME
Abstract
A dielectric composition includes a ceramic powder, a high
polymerization binder, and a low polymerization binder type
dispersant having a degree of polymerization between 100 and
1,000.
Inventors: |
CHUN; Jin Sung; (Suwon-si,
KR) ; KIM; Seul Gi; (Suwon-si, KR) ; SEO; Hyo
Kyong; (Suwon-si, KR) ; CHUNG; Hae Suk;
(Suwon-si, KR) ; KANG; Byung Sung; (Suwon-si,
KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SAMSUNG ELECTRO-MECHANICS CO., LTD. |
Suwon-si |
|
KR |
|
|
Family ID: |
68420757 |
Appl. No.: |
16/275785 |
Filed: |
February 14, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01G 4/012 20130101;
H01G 4/248 20130101; H01G 4/1245 20130101; H01G 4/1227 20130101;
H01G 4/30 20130101; H01G 4/008 20130101 |
International
Class: |
H01G 4/12 20060101
H01G004/12; H01G 4/30 20060101 H01G004/30; H01G 4/012 20060101
H01G004/012; H01G 4/248 20060101 H01G004/248; H01G 4/008 20060101
H01G004/008 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 16, 2018 |
KR |
10-2018-0141895 |
Claims
1. A dielectric composition, comprising: a ceramic powder; a high
polymerization binder; and a low polymerization binder type
dispersant having a degree of polymerization between 100 and
1,000.
2. The dielectric composition of claim 1, wherein the low
polymerization binder type dispersant is a polyvinyl butyral
dispersant.
3. The dielectric composition of claim 1, wherein the low
polymerization binder type dispersant is included in 0.5 to 1 part
by weight based on the ceramic powder of 100 parts by weight.
4. The dielectric composition of claim 1, wherein the high
polymerization binder has a degree of polymerization greater than
1,000.
5. The dielectric composition of claim 1, wherein the high
polymerization binder comprises 4.5 to 9.0 parts by weight based on
the ceramic powder of 100 parts by weight.
6. The dielectric composition of claim 1, wherein the ceramic
powder is selected from the group consisting of BaTiO.sub.3,
(Ba.sub.1-xCa.sub.x)(Ti.sub.1-yCa.sub.y)O.sub.3,
(Ba.sub.1-xCa.sub.x)(Ti.sub.1-yZr.sub.y)O.sub.3,
Ba(Ti.sub.1-yZr.sub.y)O.sub.3, or
(Ba.sub.1-xCa.sub.x)(Ti.sub.1-ySn.sub.y)O.sub.3, wherein x is 0 to
0.9, and y is 0 to 0.9, and a mixture thereof.
7. The dielectric composition of claim 2, wherein the polyvinyl
butyral dispersant is a compound represented by the following
formula (I): ##STR00002## wherein: R is n-propyl; l is an integer
from 1 to 200; m is an integer from 1 to 200; and n is an integer
from 1 to 200.
8. A capacitor component, comprising: a body comprising a
dielectric layer, and first and second internal electrodes opposing
each other with the dielectric layer interposed therebetween; and
first and second external electrodes disposed externally on the
body and electrically connected to the first and second internal
electrodes, respectively, wherein the dielectric layer contains
phosphorus (P) in an amount of 0.1 wt % or lower.
9. The capacitor component of claim 8, wherein, when an energy
dispersive spectrometer analysis is performed, P is not detected in
the dielectric layer.
10. The capacitor component of claim 8, wherein the dielectric
layer is formed of a dielectric composition comprising a ceramic
powder, a high polymerization binder, and a low polymerization
binder type dispersant having a degree of polymerization between
100 and 1,000.
11. The capacitor component of claim 8, wherein the ceramic powder
is selected from the group consisting of BaTiO.sub.3,
(Ba.sub.1-xCa.sub.x)(Ti.sub.1-yCa.sub.y)O.sub.3,
(Ba.sub.1-xCa.sub.x)(Ti.sub.1-yZr.sub.y)O.sub.3,
Ba(Ti.sub.1-yZr.sub.y)O.sub.3, or
(Ba.sub.1-xCa.sub.x)(Ti.sub.1-ySn.sub.y)O.sub.3, wherein x is 0 to
0.9, and y is 0 to 0.9, and a mixture thereof.
12. The capacitor component of claim 8, wherein the low
polymerization binder type dispersant is a polyvinyl butyral
dispersant.
13. The capacitor component of claim 8, wherein the polyvinyl
butyral dispersant is a compound represented by the following
##STR00003## wherein: R is n-propyl; l is an integer from 1 to 200;
m is an integer from 1 to 200; and n is an integer from 1 to
200.
14. The capacitor component of claim 8, wherein a thickness of the
first and second internal electrodes is less than 1 .mu.m, and a
thickness of the dielectric layer is less than 2.8 .mu.m.
15. The capacitor component of claim 8, wherein, when a thickness
of the first and second internal electrodes is defined as te, and a
thickness of the dielectric layer is defined as td, te and td
satisfy td>2*te.
16. The capacitor component of claim 8, wherein the first and
second external electrodes each comprise an electrode layer and a
conductive resin layer disposed on the electrode layer.
17. The capacitor component of claim 16, wherein the electrode
layer comprises glass and one or more conductive metals selected
from a group comprised of copper (Cu), silver (Ag), nickel (Ni) and
alloys thereof.
18. The capacitor component of claim 16, wherein the conductive
resin layer comprises a base resin and one or more conductive
metals selected from a group comprised of copper (Cu), silver (Ag),
nickel (Ni) and alloys thereof.
19. The capacitor component of claim 16, wherein the body comprises
first and second surfaces opposing each other, third and fourth
surfaces connected to the first and second surfaces and opposing
each other, and fifth and sixth surfaces connected to the first to
fourth surfaces and opposing each other, wherein the first external
electrode is disposed on the third surface, and comprises a band
portion extending to portions of the first and second surfaces, and
wherein a distance from the third surface to an end of the band
portion of the electrode layer is shorter than a distance from the
third surface to an end of the band portion of the conductive resin
layer.
Description
CROSS-REFERENCE TO RELATED APPLICATION(S)
[0001] This application claims benefit of priority to Korean Patent
Application No. 10-2018-0141895 filed on Nov. 16, 2018 in the
Korean Intellectual Property Office, the disclosure of which is
incorporated herein by reference in its entirety.
BACKGROUND
1. Field
[0002] The present disclosure relates to a dielectric composition
to which a non-phosphate dispersant is applied and a capacitor
component using the same.
2. Description of Related Art
[0003] A multilayer ceramic capacitor (MLCC) is a chip-type
condenser mounted on the printed circuit substrates of a variety of
electronic products such as an image display device, including
liquid crystal displays (LCD) and plasma display panels (PDP),
computers, smartphones, cellular phones, and the like, serving to
charge and discharge electricity.
[0004] A multilayer ceramic capacitor may be used as a component of
various electronic devices as it is relatively small in size and is
able to secure high capacity while being easily installed. As
electronic devices such as computers, mobile devices, and the like,
have been miniaturized and increased in power, there has been
increased demand for miniaturized and high capacity multilayer
ceramic capacitors.
[0005] Recently, there has been increased interest in electrical
components, and multilayer ceramic capacitors have been required to
have high reliability and high strength properties to be used in
vehicles or infotainment systems.
[0006] To this end, grains included in a dielectric sheet may be
required to have an appropriate grain size and to have uniform
grain size distribution.
[0007] In the prior art, a phosphate dispersant including
phosphoric acid may be used to disperse a dielectric powder, but a
large amount of a secondary phase which becomes impurities may be
created after sintering, and thus, abnormal grain growth may be
facilitated. Thus, a non-phosphate dispersant which does not
include phosphoric acid, while securing sufficient dispersion
force, may be necessary.
SUMMARY
[0008] An aspect of the present disclosure is to provide a
dielectric composition to which a non-phosphate dispersant is
applied and a capacitor component using the same.
[0009] According to an aspect of the present disclosure, a
dielectric composition includes a ceramic powder, a high
polymerization binder, and a low polymerization binder type
dispersant having a degree of polymerization between 100 and
1,000.
[0010] According to another aspect of the present disclosure, a
capacitor component includes a body comprising a dielectric layer,
and first and second internal electrodes opposing each other with
the dielectric layer interposed therebetween, and first and second
external electrodes disposed externally on the body and
electrically connected to the first and second internal electrodes,
respectively. The dielectric layer contains phosphorus (P) in an
amount of 0.1 wt % or lower.
BRIEF DESCRIPTION OF DRAWINGS
[0011] 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:
[0012] FIG. 1 is a structural formula of one example of a polyvinyl
butyral dispersant;
[0013] FIG. 2 is a structural formula of one example of a phosphate
dispersant;
[0014] FIG. 3 is a schematic diagram illustrating an abnormal grain
growth of a dielectric layer;
[0015] FIGS. 4A and 4B are images of analysis of a dielectric layer
(embodiment) formed using a polyvinyl butyral dispersant;
[0016] FIGS. 5A and 5B are images of analysis of a dielectric layer
(comparative example) formed using a phosphate dispersant;
[0017] FIG. 6 is a perspective diagram illustrating a capacitor
component according to another exemplary embodiment in the present
disclosure;
[0018] FIG. 7 is a cross-sectional diagram taken along line I-I' in
FIG. 6;
[0019] FIG. 8A is a diagram illustrating a ceramic green sheet on
which a first internal electrode is printed, and FIG. 8B is a
diagram illustrating a ceramic green sheet on which a second
internal electrode is printed;
[0020] FIG. 9 is a diagram illustrating a region P1 illustrated in
FIG. 7 in magnified form; and
[0021] FIG. 10 is a diagram illustrating a region P2 illustrated in
FIG. 7 in magnified form.
DETAILED DESCRIPTION
[0022] Hereinafter, embodiments of the present disclosure will be
described as follows with reference to the attached drawings.
[0023] The present disclosure may, however, be exemplified in many
different forms and should not be construed as being 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, shapes and sizes of elements in the
drawings may be exaggerated for clear description, and elements
indicated by the same reference numeral are same elements in the
drawings.
[0024] In the drawings, certain elements may be omitted to clearly
describe the present disclosure, and to clearly express a plurality
of layers and areas, thicknesses may be magnified. The same
elements having the same function within the scope of the same
concept will be described using the same reference numeral.
Further, throughout the specification, it will be understood that
when a portion "includes" an element, it can further include
another element, not excluding another element, unless otherwise
indicated.
[0025] In the drawing, an X direction is a second direction, an L
direction, or a length direction, a Y direction is a third
direction, a W direction, or a width direction, and a Z direction
is a first direction, a layering direction, a T direction, or a
thickness direction.
[0026] Dielectric Composition
[0027] A dielectric composition according to an exemplary
embodiment may include a ceramic powder, a high polymerization
binder, and a low polymerization binder type dispersant having a
degree of polymerization between 100 and 1,000.
[0028] The ceramic powder may be a barium titanate (BaTiO.sub.3)
powder. The ceramic powder may have one or more elements such as
calcium (Ca), zirconium (Zr), tin (Sn), or the like, employed in
barium titanate such as
(Ba.sub.1-xCa.sub.x)(Ti.sub.1-yCa.sub.y)O.sub.3,
(Ba.sub.1-xCa.sub.x)(Ti.sub.1-yZr.sub.y)O.sub.3,
Ba(Ti.sub.1-yZr.sub.y)O.sub.3, or
(Ba.sub.1-xCa.sub.x)(Ti.sub.1-ySn.sub.y)O.sub.3, wherein x is 0 to
0.9, and y is 0 to 0.9, or a mixture thereof, but the ceramic
powder is not limited thereto.
[0029] The low polymerization binder type dispersant having a
degree of polymerization between 100 and 1,000 in the exemplary
embodiment may not include phosphoric acid, and a secondary phase
and an abnormal grain growth may thus be prevented. By preventing
abnormal grain growth, a dielectric layer having a uniform
microstructure may be manufactured, and reliability of a capacitor
component may improve. Also, by using a low polymerization binder
type dispersant in accordance with the exemplary embodiment,
viscosity of the dielectric composition may be adjusted, thereby
reducing the time required for an evaporating operation. The
viscosity of the dielectric composition may be about 50 to about
300 (CPS).
[0030] A multilayer ceramic capacitor may be manufactured by
processes such as an arranging process (a process of preparing a
dielectric composition), a process of forming a sheet, a process of
printing an internal electrode, a layering process, a compressing
process, a cutting process, a plasticizing process, a sintering
process, a process of forming an external electrode, a burn-in
process, a plating process, a measuring process, and the like, and
the arranging process (a process of preparing a dielectric
composition), the initial process, may greatly affect properties of
a multilayer ceramic capacitor.
[0031] When a dielectric composition is prepared, a dispersant may
be used for uniform dispersion between a ceramic powder and a
binder. Representative dispersion methods for uniform dispersion
may be an electrostatic repulsion dispersion method and a steric
hindrance dispersion method. The electrostatic repulsion dispersion
method uses a phosphate dispersant to endow a ceramic powder with
electrostatic repulsion properties.
[0032] FIG. 3 is a schematic diagram illustrating an abnormal grain
growth 11c of a dielectric layer 11' when a multilayer ceramic
capacitor is manufactured using a phosphate dispersant.
[0033] Referring to FIG. 3, when a chip is manufactured using an
inorganic phosphate dispersant, an optimal sintering temperature
may be locally changed by phosphoric acid, and an abnormal grain
growth 11c may occur by non-uniform arrangement of atoms during a
dielectric sintering process. Accordingly, when a chip is finally
manufactured, a microstructure may be non-uniform, or numerous weak
points causing cracks may be created, which may lead to degradation
of properties of a multilayer ceramic capacitor.
[0034] In the case in which a multilayer ceramic capacitor is
manufactured using a phosphate dispersant, phosphoric acid may
exist in P2O5 form, and may become liquid at 520.degree. C. during
a sintering process, and a homogeneous surface doping layer may be
formed on a ceramic powder. Thereafter, when the temperature
continuously increases to be higher than 520.degree. C., the P2O5
doped on the surface may react with BaO components included in the
ceramic powder, and a variety of barium phosphorus (Ba--P)
intermediate compounds may be created, and as barium (Ba) included
in the ceramic powder is exhausted, a titanium oxide-rich phase may
be formed. The titanium oxide may facilitate the sintering by
forming liquid at 1310.degree. C., a BaTiO3-TiO2 eutectic
temperature, and may cause abnormal grain growth. Also, the
intermediate compounds may exist as a secondary phase. The
secondary phase and the abnormally grown grains may degrade
breakdown voltage (BDV) properties, high acceleration lifespan
properties, and the like, which may degrade reliability of the
multilayer ceramic electronic component.
[0035] By using the low polymerization binder type dispersant, the
dispersibility of the dielectric composition is improved, and
abnormal grain growth during sintering can be decreased. The low
polymerization binder type dispersant according to the exemplary
embodiment may have a degree of polymerization of between 100 and
1,000. In one embodiment of the present invention, the lower
polymerization binder type dispersant may have a degree of
polymerization of 200, 300, 400, 500, 600, 700, 800, or 900.
[0036] When a degree of polymerization is less than 100,
dispersibility may be uniformly secured, but it may be difficult to
control stretchability due to a plasticizing effect when a green
sheet is manufactured using a dielectric compound. When a degree of
polymerization is greater than 1,000, the dispersibility may
degrade, and compatibilities with the binder may also degrade,
which may lead to degradation of surface roughness of the green
sheet.
[0037] The low polymerization binder type dispersant may be a
polyvinyl butyral dispersant. More particularly, the low
polymerization binder type dispersant may have a structural formula
of a polyvinyl butyral dispersant represented by the following
formula (I):
##STR00001##
wherein in the formula (I): R may be a liner- or branched-chain
alkyl group having 1 to 6 carbon atoms, such as methyl, ethyl,
n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, sec-butyl,
1-ethylpropyl, n-pentyl, neopentyl, n-hexyl, isohexyl,
3-methylphentyl; l is an integer from 1 to 200; m is an integer
from 1 to 200; n is an integer from 1 to 200.
[0038] The polyvinyl butyral dispersant may be removed by a thermal
sintering process for manufacturing a capacitor. Thus, the
polyvinyl butyral dispersant may not affect a dielectric grain
growth differently from a phosphate dispersant.
[0039] Also, a polypropylene glycol monoalkyl ether dispersant such
as propylene glycol methyl ether, another non-phosphate dispersant,
may have a boiling point of 120.degree. C., and have a molecular
weight of 90 g/mol, whereas the polyvinyl butyral dispersant, the
low polymerization binder type dispersant in the exemplary
embodiment, may have a higher boiling point of 145.degree. C.
Accordingly, according to the exemplary embodiment, it may be easy
to establish conditions of a forming process and a process of
drying a formed sheet during a process of manufacturing a
multilayer ceramic condenser, and 10,000 g/mol or higher of
molecular weight may be synthesized. Thus, implementation of sheet
strength may improve.
[0040] The low polymerization binder type dispersant in the
dielectric composition according to the exemplary embodiment may
include 0.5 to 1 part by weight based on the ceramic powder of 100
parts by weight in the dielectric composition. In one embodiment of
the present invention, the low polymerization binder type
dispersant may include 0.6 part by weight, 0.7 part by weight, 0.8
part by weight, or 0.9 part by weight based on the ceramic powder
of 100 parts by weight in the dielectric composition.
[0041] When the low polymerization binder type dispersant is
included less than 0.5 part by weight, dispersibility may degrade
due to coarse grains formed by agglomeration of a ceramic powder.
When the low polymerization binder type dispersant is greater than
1 part by weight, physical properties of a ceramic sheet
manufactured using a dielectric composition may degrade, and a
large amount of carbon residues may be created during a
plasticizing process.
[0042] The high polymerization binder may have a degree of
polymerization greater than 1,000. In one embodiment of the present
invention, the high polymerization binder may have a degree of
polymerization greater than 10,000, 100,000, or 1,000,000, and less
than 10,000,000, less than 100,000,000, or less than 1,000,000,000.
Examples of the high polymerization binder of the present invention
include: Ethylene Vinyl Acetate (EVA), Polyvinyl butyral (PVB), and
Polyacrylonitrile (PAN). A molecular weight of the high
polymerization binder ranges from about 6.0.times.10.sup.4 to about
11.0.times.10.sup.4 (or more than 6.0.times.10.sup.4). The high
polymerization binder may not include phosphoric acid.
[0043] With regard to the high polymerization binder, a high
polymerization binder may be generally used to secure stability of
a formed sheet. In this case, a degree of polymerization may be
related to viscosity of slurry, and it may be necessary to use an
appropriate high polymerization binder in terms of a thickness of a
sheet to use.
[0044] The high polymerization binder may be included 4.5 to 9.0
parts by weight based on the ceramic powder of 100 parts by weight
in the dielectric composition. In one embodiment of the present
invention, the high polymerization binder may be included 5.0 parts
by weight, 5.5 parts by weight, 6.0 parts by weight, 6.5 parts by
weight, 7.0 parts by weight, 7.5 parts by weight, 8.0 parts by
weight, or 8.5 parts by weight based on the ceramic powder of 100
parts by weight in the dielectric composition.
Experimental Embodiment
[0045] FIGS. 4A and 4B are images of analysis of a dielectric layer
formed using a polyvinyl butyral dispersant (embodiment). FIGS. 5A
and 5B are images of analysis of a dielectric layer formed using a
phosphate dispersant (comparative example).
[0046] The polyvinyl butyral dispersant in the embodiment is a
polyvinyl butyral dispersant having a structural formula in FIG. 1,
and the phosphate dispersant in the comparative example may be
BYK-103, a phosphate dispersant having a structural formula in FIG.
2. The BYK-103 may be a dispersant having a structure in which
polyethylene glycol (PEG) units are connected in an ester structure
and including phosphoric acid.
[0047] Comparing FIGS. 4A and 5A, the images taken by a scanning
electron microscope (SEM), grains included in the dielectric layer
in the embodiment (FIG. 4A) had smaller diameters and were more
uniformly dispersed, as compared to grains included in the
dielectric layer in the comparative example (FIG. 5A).
[0048] Also, comparing FIGS. 4B and 5B, results of observation of
an abnormal grain growth in an SEM-energy-selective backscatter
(EsB) mode, a plurality of abnormal grain growths 11c occurred in
the comparative example, but in the embodiment, almost no abnormal
grain growth occurred.
[0049] In each of the comparative examples and the embodiments,
4000 samples were prepared, and a high accelerated life test (HALT)
were performed at temperature of 130.degree. C. and at 2.times.Vr
(constant voltage). As a result, in the embodiment, seven samples
were defective (defective rate: 0.18%) out of 4000 samples, and in
the comparative example, 27 samples were defective (defective rate:
0.68%) out of 4000 samples.
[0050] Thus, according to the exemplary embodiment, by applying the
non-phosphate low polymerization binder type dispersant,
reliability may improve.
[0051] Capacitor Component
[0052] FIG. 6 is a perspective diagram illustrating a capacitor
component according to another exemplary embodiment.
[0053] FIG. 7 is a cross-sectional diagram taken along line I-I' in
FIG. 6.
[0054] FIG. 8A is a diagram illustrating a ceramic green sheet on
which a first internal electrode is printed, and FIG. 8B is a
diagram illustrating a ceramic green sheet on which a second
internal electrode is printed.
[0055] FIG. 9 is a diagram illustrating a Region P1 illustrated in
FIG. 7 in magnified form.
[0056] FIG. 10 is a diagram illustrating a Region P2 illustrated in
FIG. 7 in magnified form.
[0057] In the description below, a capacitor component according to
an exemplary embodiment will be described with reference to FIGS. 6
to 10.
[0058] A capacitor component 100 according to another exemplary
embodiment may be manufactured using the dielectric composition in
the exemplary embodiment described above.
[0059] The capacitor component 100 according to the exemplary
embodiment may include a body 110 comprising a dielectric layer
111, and first and second internal electrodes 121 and 122 opposing
each other with the dielectric layer interposed therebetween, and
first and second external electrodes 131 and 132 disposed
externally on the body 110 and electrically connected to the first
and second internal electrodes, respectively. The dielectric layer
may contain P of 0.1 wt % or lower.
[0060] In the body 110, the dielectric layer 111 and the internal
electrodes 121 and 122 may be alternately layered.
[0061] A shape of the body 110 may not be limited to any particular
shape, but as illustrated in the diagram, the body 110 may have a
hexahedral shape or a shape similar to a hexahedron. Due to
contraction of a ceramic powder included in the body 110 during a
sintering process, the body 110 may have substantially a hexahedral
shape although the hexahedral shape may not be an exact hexahedron
formed by straight lines.
[0062] The body 110 may have first and second surfaces 1 and 2
opposing each other in a thickness direction (Z direction), third
and fourth surfaces 3 and 4 connected to the first and second
surfaces 1 and 2 and opposing each other in a length direction (X
direction), and fifth and sixth surfaces 5 and 6 connected to the
first and second surfaces 1 and 2 and the third and fourth surfaces
3 and 4 and opposing each other in a width direction (Y
direction).
[0063] The plurality of dielectric layers 111 forming the body 110
may be in a sintered state, and the dielectric layers 111 may be
integrated such that boundaries between adjacent dielectric layers
111 may be difficult to identify without using a scanning electron
microscope (SEM).
[0064] The dielectric composition forming the dielectric layers 111
may include a ceramic powder, a high polymerization binder, and a
low polymerization binder type dispersant having a degree of
polymerization between 100 and 1,000, as described in the
aforementioned exemplary embodiment. The descriptions of the
dielectric composition overlapping the aforementioned descriptions
will not be repeated.
[0065] According to the exemplary embodiment, as the low
polymerization binder type dispersant having a degree of
polymerization between 100 and 1,000 is used instead of a phosphate
dispersant, the dielectric layer may contain phosphorus (P) in an
amount of 0.1 wt % or lower, preferably 0.05 wt % or lower, or more
preferably 0.01 wt % or lower. The configuration in which a content
of P is 0.1 wt % or lower may indicate that P may be added to the
minimum as an impurity, and that P may not be included in the
dielectric composition, a material of the dielectric layer.
[0066] Thus, the dielectric layer 111 in the exemplary embodiment
may have a uniform microstructure and improved reliability as an
abnormal grain growth is prevented.
[0067] Further, in the dielectric layers 111, P may not be detected
when energy dispersive spectrometer analysis is performed.
[0068] The body 110 may include a capacitance forming portion
disposed in the body 110 and forming capacitance including the
first internal electrode 121 and the second internal electrode 122
disposed to oppose each other with the dielectric layer 111
interposed therebetween, and upper and lower cover portions 112 and
113 disposed on upper and lower portions of the capacitance forming
portion.
[0069] The capacitance forming portion may contribute to formation
of capacitance of a capacitor, and may be formed by alternately
layering the plurality of the first and second internal electrodes
121 and 122 with the dielectric layers 111 interposed
therebetween.
[0070] The upper cover portion 112 and the lower cover portion 113
may be formed by disposing a single dielectric layer or by layering
two or more dielectric layers on upper and lower surfaces of the
capacitance forming portion, respectively, and may prevent damage
to an internal electrode caused by physical or chemical stress.
[0071] The upper cover portion 112 and the lower cover portion 113
may not include an internal electrode, and may include the same
material as a material of the dielectric layers 111.
[0072] The plurality of the first and second internal electrodes
121 and 122 may be disposed to oppose each other with the
dielectric layers 111 interposed therebetween.
[0073] The internal electrodes may include the first and second
internal electrodes 121 and 122 alternately disposed with the
dielectric layers 111 interposed therebetween.
[0074] The first and second internal electrodes 121 and 122 may be
exposed to the third and fourth surfaces 3 and 4 of the body 110,
respectively.
[0075] Referring to FIG. 7, the first internal electrode 121 may be
spaced apart from the fourth surface 4 and may be exposed through
the third surface. The second internal electrode 122 may be spaced
apart from the third surface 3 and may be exposed through the
fourth surface 4. The first external electrode 131 may be disposed
on the third surface 3 of the body and connected to the first
internal electrode 121, and the second external electrode 132 may
be disposed on the fourth surface 4 and connected to the second
internal electrode 122.
[0076] The first and second internal electrodes 121 and 122 may be
electrically isolated from each other by the dielectric layer 111
interposed therebetween. The body 110 may be formed by layering a
ceramic green sheet (FIG. 8A) on which the first internal electrode
121 is printed and a ceramic green sheet (FIG. 8B) on which the
second internal electrode 122 is printed, and performing a
sintering process.
[0077] A method of printing the conductive paste may be a screen
printing method, a gravure printing method, or the like. However,
the method is not limited thereto.
[0078] The first and second external electrodes 131 and 132 may be
disposed in an outer portion of the body 110 and may be connected
to the first and second internal electrodes 121 and 122,
respectively. As illustrated in FIG. 7, the first and second
external electrodes 131 and 132 respectively connected to the first
and second internal electrodes 121 and 122 may be included.
[0079] The first and second external electrodes 131 and 132 may be
electrically connected to the first and second internal electrodes
121 and 122, respectively, to form capacitance, and the second
external electrode 132 may be connected to a potential different
from a potential to which the first external electrode 131 is
connected.
[0080] The external electrodes 131 and 132 may include electrode
layers 131a and 132a, respectively, connected to the internal
electrodes 121 and 122, respectively, and conductive resin layers
131b and 132b disposed on the electrode layers, respectively.
[0081] The external electrodes 131 and 132 may further include
Nickel (Ni) plated layers 131c and 132c disposed on the conductive
resin layers 131b and 132b, and Tin (Sn) plated layers 131d and
132d disposed on the Ni plated layers 131c and 132c.
[0082] When the first and second external electrodes 131 and 132
include the first and second external electrodes 131 and 132, the
first external electrode 131 may include the electrode layer 131a,
the first conductive resin layer 131b, the first Ni plated layer
131c, and the first Sn plated layer 131d, and the second external
electrode 132 may include the second electrode layer 132a, the
second conductive resin layer 132b, the first Ni plated layer 132c
and the first Sn plated layer 132d.
[0083] The electrode layers 131a and 132a may include one or more
conductive metals and glass.
[0084] The conductive metal used in the electrode layers 131a and
132a may not be limited to any particular material as long as the
electrode layers 131a and 132a are able to be electrically
connected to the internal electrodes. The conductive material may
include, for example, one or more materials selected from a group
comprised of copper (Cu), silver (Ag), nickel (Ni), and alloys
thereof.
[0085] The electrode layers 131a and 132a may be formed by applying
a conductive paste made by adding glass frit to a powder of the
conductive metal, and performing a sintering process.
[0086] The conductive resin layers 131b and 132b may be formed on
the electrode layers 131a and 132a, and may entirely cover the
electrode layers 131a and 132a.
[0087] The conductive resin layers 131b and 132b may include a
conductive metal and a base resin.
[0088] The base resin included in the conductive resin layers 131b
and 132b may not be limited to any particular material as long as
the material has adhesion properties and shock absorption
properties and is able to be mixed with the conductive metal powder
to make a paste. The material may include an epoxy resin, for
example.
[0089] The conductive metal included in the conductive resin layers
131b and 132b may not be limited to any particular material as long
as the material is able to be electrically connected to the
electrode layers 131a and 132a. The material may include, for
example, one or more materials selected from a group comprised of
copper (Cu), silver (Ag), nickel (Ni) and alloys thereof.
[0090] The Ni plated layers 131c and 132c may be formed on the
conductive resin layers 131b and 132b, and may entirely cover the
conductive resin layers 131b and 132b.
[0091] The Sn plated layer 131d and 132d may be formed on the Ni
plated layers 131c and 132c, and may entirely cover the Ni plated
layers 131c and 132c.
[0092] The Sn plated layer 131d and 132d may improve mounting
properties.
[0093] The first and second external electrodes 131 and 132 may
include a connection portion C disposed on the third surface 3, and
a band portion B extending to portions of the first and second
surfaces 1 and 2 from the connection portion C. Similarly, the
second external electrode 132 may include a connection portion
disposed on the fourth surface 4 of the body, and a band portion
extending to portions of the first and second surfaces 1 and 2 from
the connection portion.
[0094] The band portion B may extend to portions of the fifth and
sixth surfaces 5 and 6 from the connection portion C as well as
extending to the first and second surfaces 1 and 2.
[0095] Referring to FIG. 9, a first external electrode 131 may be
configured such that a distance l1 from a third surface 3 of a body
110 to an end of a band portion B of a first electrode layer 131a
may be shorter than a distance l2 to an end of the band portion B
of a first conductive resin layer 131b.
[0096] Similarly, a second external electrode 132 may be configured
such that a distance from a fourth surface 4 of the body 110 to an
end of the band portion of a second electrode layer 132a may be
shorter than a distance to an end of the band portion of a second
conductive resin layer 132b.
[0097] Thus, the conductive resin layers 131b and 132b may be
configured to entirely cover the electrode layers 131a and 132a,
and strength against warpage and adhesion force between the
external electrode and the body may be enhanced.
[0098] Referring to FIG. 10, with regard to a capacitor component
according to another exemplary embodiment, a thickness, td, of a
dielectric layer 111 and a thickness, te, of internal electrodes
121 and 122 may satisfy td>2*te.
[0099] In other words, according to the exemplary embodiment, the
thickness, td, of the dielectric layer 111 may be twice greater
than the thickness, te, of the first and second internal electrodes
121 and 122.
[0100] Generally, a high voltage electrical electronic device has
had an issue of reliability caused by degradation of insulation
breakdown voltage in a high voltage environment.
[0101] The capacitor component according to the exemplary
embodiment may be configured such that the thickness, td, of the
dielectric layer 111 may be configured to be greater than two times
the thickness, te, of the internal electrodes 121 or 122 to prevent
degradation of insulation breakdown voltage in a high voltage
environment. Accordingly, the thickness of the dielectric layer, a
distance between the internal electrodes, may be increased, thereby
improving insulation breakdown voltage properties.
[0102] When the thickness, td, of the dielectric layer 111 is less
than or equal to two times the thickness, te, of the internal
electrodes 121 or 122, the thickness of the dielectric layer, a
distance between the internal electrodes, may become thin, and
insulation breakdown voltage may degrade.
[0103] The thickness, te, of the internal electrode may be less
than 1 .mu.m, and the thickness, td, of the dielectric layer 111
may be less than 2.8 .mu.m, but the thicknesses may not be limited
thereto. In one embodiment, the thickness, te, of the internal
electrode may be 0.9 .mu.m, 0.8 .mu.m, 0.7 .mu.m, 0.6 .mu.m, or 0.5
.mu.m. In one embodiment, the thickness, td, of the dielectric
layer 111 may be 2.0 .mu.m, 2.1 .mu.m, 2.2 .mu.m, 2.3 .mu.m, 2.4
.mu.m, 2.5 .mu.m, 2.6 .mu.m, or 2.7 .mu.m.
[0104] According to the aforementioned exemplary embodiments, by
applying a non-phosphate dispersant, an abnormal grain growth may
be prevented, and the dielectric layer having a uniform
microstructure may be secured, thereby improving reliability of a
capacitor component.
[0105] While the exemplary embodiments have been shown and
described above, it will be apparent to those skilled in the art
that modifications and variations could be made without departing
from the scope of the present invention as defined by the appended
claims.
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