KR20190058239A - Multilayer ceramic capacitor and method of manufacturing the same - Google Patents

Abstract

According to an aspect of the present invention, provided is a multi-layered ceramic capacitor which comprises: a body including a dielectric layer and an internal electrode; and an external electrode disposed on one surface of the body. The external electrode includes: a first electrode layer disposed on one surface of the body, being in contact with the internal electrode, and including titanium nitride (TiN); and a second electrode layer disposed on the first electrode layer.

Description

TECHNICAL FIELD [0001] The present invention relates to a multilayer ceramic capacitor,

The present invention relates to a multilayer ceramic capacitor and a manufacturing method thereof.

Increasing the importance of increasing the effective volume ratio of multilayer ceramic capacitors (the ratio of the volume contributing to total volume to capacity) with the trend toward miniaturization and high capacity of multilayer ceramic capacitors (MLCC).

Conventionally, a method of dipping the exposed surface of the internal electrode of the body into a paste by using a paste containing a conductive metal when forming the external electrode has been mainly used.

However, the thickness of the outer electrode formed by the dipping method is not uniform, and the outer electrode is formed too thin at the corner of the body, while the outer electrode is formed too thick. Therefore, it is difficult to secure a high effective volume ratio. In addition, when the plating layer is formed on the external electrode in order to improve the connectivity and mounting property of the multilayer ceramic capacitor, the reliability of the multilayer ceramic capacitor is reduced due to penetration of the plating liquid into the inside of the body. There was a problem.

One of the objects of the present invention is to provide a multilayer ceramic capacitor in which a thin and dense primary electrode layer is formed in the body of a multilayer ceramic capacitor, thereby ensuring sufficient moisture and moisture reliability even when the thickness of the external electrode is thin, Capacitor.

According to an aspect of the present invention, there is provided a plasma display panel comprising a body including a dielectric layer and an internal electrode, and an external electrode disposed on one side of the body, wherein the external electrode is disposed on one surface of the body, (TiN); And a second electrode layer disposed on the first electrode layer.

According to another aspect of the present invention, there is provided a method of manufacturing a plasma display panel, comprising: preparing a body including a dielectric layer and an internal electrode; Forming a first electrode layer including titanium nitride (TiN) on an entire surface of the body by an atomic layer deposition method; Forming a second electrode layer on a portion of the body where the first electrode layer is formed, on which the first and second external electrodes are to be formed; And etching the exposed portion of the first electrode layer in the body having the second electrode layer to remove the exposed portion of the first electrode layer.

The multilayer ceramic capacitor according to an embodiment of the present invention can form a thin and dense primary electrode layer in the body of the multilayer ceramic capacitor, so that even when the thickness of the external electrode is thin, it is possible to secure sufficient moisture and moisture reliability, have.

FIG. 1 schematically shows a perspective view of a multilayer ceramic capacitor according to an embodiment of the present invention.
Fig. 2 schematically shows a cross-sectional view of II 'in Fig.
Fig. 3 schematically shows a cross-sectional view of an enlarged view of part A of Fig.
Fig. 4 schematically shows a cross-sectional view of an enlarged portion B in Fig.
5 is a schematic cross-sectional view of a portion B of a multilayer ceramic capacitor according to another embodiment of the present invention.
6 is a schematic cross-sectional view of a portion B of a multilayer ceramic capacitor according to another embodiment of the present invention.
7 to 10 are perspective views schematically showing steps of a method of manufacturing a multilayer ceramic capacitor according to another aspect of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to specific embodiments and the accompanying drawings. However, the embodiments of the present invention can be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below. Further, the embodiments of the present invention are provided for a more complete description of the present invention to the ordinary artisan. Accordingly, the shapes, sizes, etc. of the elements in the drawings may be exaggerated for clarity. In the drawings, like reference numerals are used to designate like elements that are functionally equivalent to the same reference numerals in the drawings.

It is to be understood that, although the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, Will be described using the symbols. Further, throughout the specification, when an element is referred to as " including " an element, it means that the element may include other elements as well, without departing from the other elements unless specifically stated otherwise.

In the drawing, the X direction may be understood as a first direction or a longitudinal direction, a Y direction as a second direction or a width direction, a Z direction as a third direction, a thickness direction, or a lamination direction, but is not limited thereto.

Multilayer Ceramic Capacitors

FIG. 1 schematically shows a perspective view of a multilayer ceramic capacitor according to an embodiment of the present invention. Fig. 2 schematically shows a cross-sectional view taken along the line I-I 'in Fig. Fig. 3 schematically shows a cross-sectional view of an enlarged view of part A of Fig. Fig. 4 schematically shows a cross-sectional view of an enlarged portion B in Fig.

Hereinafter, a multilayer ceramic capacitor 100 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 4. FIG.

1, a multilayer ceramic capacitor 100 according to an embodiment of the present invention includes a body 110 and first and second external electrodes 130 and 140 disposed outside the body 110 .

The body 110 has first and second surfaces 1 and 2 opposed to each other in the thickness direction (Z direction), first and second surfaces 1 and 2 connected to the first and second surfaces 1 and 2, And are connected to the third and fourth faces 3 and 4 and the first and second faces 1 and 2 and are connected to the third and fourth faces 3 and 4 and are connected to each other in the longitudinal direction And may have opposing fifth and sixth surfaces 5,6.

2, the body 110 includes internal electrodes 121 and 122 disposed alternately through the third and fourth surfaces 3 and 4 with a dielectric layer 111 therebetween and a dielectric layer 111 interposed therebetween, .

The body 110 is formed by laminating a plurality of dielectric layers 111 in the thickness Z direction and then firing the body 110. The shape and dimensions of the body 110 and the number of stacked layers of the dielectric layer 111 are shown in this embodiment But is not limited thereto.

The plurality of dielectric layers 111 forming the body 110 are in a baked state and the boundaries between the adjacent dielectric layers 111 can be integrated so as to be difficult to confirm without using a scanning electron microscope (SEM) have.

The raw material for forming the dielectric layer 111 is not particularly limited as long as sufficient electrostatic capacity can be obtained, for example, it may be a barium titanate (BaTiO ₃ ) powder. A variety of ceramic additives, organic solvents, plasticizers, binders, dispersants and the like may be added to the powder of the barium titanate (BaTiO ₃ ) according to the purpose of the present invention.

The internal electrodes 121 and 122 may include a first internal electrode 121 exposed through the third surface 3 and a second internal electrode 122 exposed through the fourth surface 4.

The first and second internal electrodes 121 and 122 are a pair of electrodes having different polarities and are electrically insulated from each other by a dielectric layer 111 disposed in the middle.

The first and second internal electrodes 121 and 122 are alternately exposed to the third and fourth surfaces 3 and 4 in the longitudinal direction (X direction) of the body 110, And the first and second external electrodes 130 and 140, respectively.

The thickness of the first and second internal electrodes 121 and 122 may be determined depending on the application.

For example, the widths of the first and second internal electrodes 121 and 122 may be formed to satisfy the range of 0.2 to 1.0 μm in consideration of the size of the body 110, but are not limited thereto.

The first and second internal electrodes 121 and 122 may be formed of a single material such as nickel (Ni), copper (Cu), palladium (Pd), silver (Ag), lead (Pb) And may include a conductive metal.

And a cover layer 112 formed by stacking dielectric layers not having internal electrodes on upper and lower parts of the body 110, respectively. The cover layer 112 can serve to maintain the reliability of the multilayer ceramic capacitor against an external impact.

The external electrodes 130 and 140 are disposed on one side of the body 110 and are in contact with the internal electrodes 121 and 122 and include first electrode layers 131 and 141 including TiN and first electrode layers 131 and 141 And second electrode layers 132 and 142 disposed on the second electrode layers 132 and 142.

The external electrodes 130 and 140 may include first and second external electrodes 130 and 140 connected to the first and second internal electrodes 121 and 122, respectively.

The first and second external electrodes 130 and 140 may include a connection portion formed on the third and fourth surfaces 3 and 4 of the body 110, 5 and the sixth surface 1, 2, 5, 6, and an edge portion where the connection portion and the band portion are in contact with each other.

Referring to FIGS. 3 and 4, the structure of the first and second external electrodes 130 and 140 of the multilayer ceramic capacitor according to an embodiment of the present invention will be described in more detail. FIGS. 3 and 4 are enlarged views of the first external electrode 130, and descriptions thereof are also applicable to the second external electrode 140. FIG.

The first electrode layer 131 includes TiN (titanium nitride). Further, it can be made of TiN alone.

TiN is excellent in acid resistance and durability, and has a low possibility of breakage during the process, and has an advantage of excellent adhesion with ceramics and metals. In addition, the moisture permeability is low, thereby improving the moisture resistance reliability.

The first electrode layer 131 may be formed by atomic layer deposition (ALD).

ALD technology is a technique of depositing a thin film or a protective film on the surface of a substrate during a semiconductor process. Unlike the conventional deposition technique in which a thin film is chemically deposited, the ALD technique is a technique of growing a thin film by stacking atom layers. The ALD method is excellent in step-coverage, has an advantage in that it can easily control the thickness of a thin film, and can form a uniform thin film.

Also, when the first electrode layer is formed by the ALD method using TiN, the interconnectivity between the inner electrode and the outer electrode can be sufficiently secured even with a thickness of about 5 nm. Accordingly, the thickness of the external electrode can be reduced, and the effective volume ratio can be increased.

The thickness of the first electrode layer 131 may be 10 to 500 nm.

If the thickness of the first electrode layer 131 is less than 10 nm, there is a fear that sufficient moisture permeation preventing effect may not be obtained. If it exceeds 500 nm, ESR may increase.

Table 1 below shows the results of measuring the change in moisture resistance reliability according to the maximum thickness of the first electrode layer by forming a first electrode layer with TiN using an atomic layer deposition method and forming a second electrode layer with a resin-based electrode.

The humidity resistance reliability was tested by applying a voltage of 9.5 V for 20 hours under the conditions of 85 ° C. and 85%, and 100 samples were tested for each sample in terms of the number in which no reliability defect occurred.

Sample No Thin film thickness (nm) Intrinsic reliability (%) One* One 28 2* 3 27 3 * 5 24 4* 7 73 5 10 100 6 19 100 7 51 100 8 70 100 9 98 100 10 201 100 11 294 100 12 397 100 13 499 100

As can be seen from Table 1, when the thickness of the first electrode layer is 10 nm or more, it is confirmed that the moisture-proof reliability is 100%.

Referring to FIG. 3, t2 / t1 may be 0.9 or more when the thickness of the connecting portion of the first electrode layer is defined as t1 and the thickness of the corner portion of the first electrode layer is defined as t2. Since the first electrode layer is formed using the ALD method, the thickness of the first electrode layer can be uniformly adjusted as a whole so that t2 / t1 is 0.9 or more. Accordingly, the first electrode layer may be formed to have a sufficient thickness to the edge portion, thereby blocking moisture and the penetration path of the plating liquid.

When the thickness of the band portion of the first electrode layer is defined as t3, t3 / t1 may be 0.9 to 1.1. That is, the thickness deviation of the connecting portion and the band portion can be 10% or less.

As described above, the first electrode layer can ensure sufficient moisture-proof reliability and electrode connectivity, and the second electrode layer is not particularly limited, but more preferably, the second electrode layer has a shape similar to that of FIGS. 4 to 6 Lt; / RTI >

Fig. 4 schematically shows a cross-sectional view of an enlarged portion B in Fig.

Referring to FIG. 4, the second electrode layer may be a firing electrode 132 including a conductive metal 132a and a glass 132b. The component of the glass 132b helps to form an alloy between the conductive metal 132a and the first electrode layer 131 and functions as a binder to seal.

In this case, as an example of obtaining the fired electrode 132, a paste including the conductive metal 132a and the glass 132b may be applied on the first electrode layer and fired to form the fired electrode 132 have.

At this time, the conductive metal 132a may be Cu.

5 is a schematic cross-sectional view of a portion B of a multilayer ceramic capacitor according to another embodiment of the present invention.

Referring to FIG. 5, the second electrode layer may be a resin-based electrode 132 'including a plurality of metal particles 132a' and a base resin 132b '.

The resin-based electrode 132 'is formed by dispersing a plurality of metal particles 132a` in the base resin 132b`. In this case, as an example of a resin-based electrode, a paste in which metal particles are dispersed in a base resin can be used. Since the applied paste is formed through a drying and curing process, Unlike the method, the metal particles may not be melted and may exist in the form of particles in the resin-based electrode.

At this time, the metal particles 132a 'may be at least one of Cu, Ni and Ag.

On the other hand, the metal particles 132a 'may be formed not only in a spherical shape but also in a flake form, if necessary, or in a mixed form of a spherical form and a flake form.

The base resin 132b 'may include a thermosetting resin.

At this time, the thermosetting resin may be, for example, an epoxy resin, but the present invention is not limited thereto.

The base resin 132b 'serves to mechanically bond the first electrode layer 131 and the plating layer (not shown).

6 is a schematic cross-sectional view of a portion B of a multilayer ceramic capacitor according to another embodiment of the present invention.

Referring to FIG. 6, the second electrode layer 132 'includes a plurality of metal particles 132a`, a conductive connection portion 132c`` that surrounds the plurality of metal particles, a base resin 132b``, Based electrode 132 '' including an intermetallic compound 132d` that contacts the first electrode layer 131 and the conductive connection portion 132c``.

The resin-based electrode 132 'containing the intermetallic compound 132d` is formed by dispersing a plurality of metal particles 132a`` in the base resin 132b``.

At this time, the metal particles 132a` may be at least one of Cu, Ni, Ag, Ag coated Cu, and Sn coated Cu.

On the other hand, the metal particles 132a`` may be formed not only in a spherical shape but also in a flake form, if necessary, or in a mixed form of a spherical form and a flake form.

The base resin 132b` may include a thermosetting resin.

At this time, the thermosetting resin may be, for example, an epoxy resin, but the present invention is not limited thereto.

The base resin 132b` serves to mechanically bond the first electrode layer 131 and the plating layer (not shown).

The conductive connection part 132c '' is formed to surround a plurality of metal particles 132a 'in a molten state and to connect the plurality of metal particles 132a` to each other, thereby minimizing the stress in the body 110, Can be improved.

At this time, the metal included in the conductive connection portion 132c` may have a melting point lower than the curing temperature of the base resin 132b``.

That is, since the conductive connecting portion 132c 'has a melting point lower than the curing temperature of the base resin 132b``, the conductive connecting portion 132c`` is melted in the course of the drying and curing process, `) Can cover the metal particles 132a` in a molten state.

At this time, the metal of the conductive connection portion preferably has a temperature of 300 ° C? Or less. For example, Sn having a melting point of 213 to 220 ° C.

The intermetallic compound 132d` is disposed to be in contact with the first electrode layer 131 and serves to reduce the contact resistance between the resin electrode 132`` and the first electrode layer 131. [ The intermetallic compound 132d contacts the conductive connection part 132c to connect the first electrode layer 131 and the conductive connection part 132c.

In this case, as an example of the resin-based electrode 132 ', at least one metal particle of Cu, Sn coated with Cu, Ni, Ag, Ag coated on the base resin, and a base resin 132b ` Melting point metal having a melting point lower than the curing temperature of the conductive paste is used. Since the applied paste is formed through a drying and curing process, unlike the conventional method of forming external electrodes by firing, And can be present in the resin-based electrode in the form of particles without being melted.

At this time, the low melting point metal may be at least one of Sn / Bi, Sn-Pb, Sn-Cu, Sn-Ag and Sn-Ag-Cu.

The external electrodes 130 and 140 may further include a plating layer (not shown) formed on the second electrode layers 132 and 142.

Further, the plating layer may have a multi-layer structure. For example, the plating layer may be formed of a multi-layered structure of Ni / Sn, Sn / Ni / Sn, Cu / Ni / Sn and the like.

Manufacturing Method of Multilayer Ceramic Capacitor

7 to 10 are perspective views schematically showing respective steps of a method of manufacturing a multilayer ceramic capacitor according to another aspect of the present invention.

A method of manufacturing a multilayer ceramic capacitor according to another aspect of the present invention includes: preparing a body including a dielectric layer and an internal electrode; Forming a first electrode layer including TiN (Titanium Nitride) on the front surface of the body by an atomic layer deposition method; Forming a second electrode layer on a portion of the body where the first electrode layer is formed, on which the first and second external electrodes are to be formed; And etching the exposed portion of the first electrode layer from the body having the second electrode layer formed thereon.

Referring to FIG. 7, a step of providing a body including the dielectric layer 211 and the internal electrodes 221 and 222 may be performed.

A slurry including a powder such as barium titanate (BaTiO ₃ ) is coated on a carrier film and dried to prepare a plurality of ceramic sheets.

The ceramic sheet may be prepared by mixing a ceramic powder such as barium titanate (BaTiO ₃ ), a binder, a solvent, etc. to prepare a slurry, and the slurry may be formed into a sheet having a thickness of several micrometers through a doctor blade method .

Next, a conductive paste containing a conductive metal can be provided. The conductive metal may be a single or an alloy of nickel (Ni), copper (Cu), palladium (Pd), silver (Ag), lead (Pb) or platinum (Pt) And the conductive paste for internal electrodes containing 40 to 50% by weight of the conductive metal can be provided.

The internal electrode conductive paste may be applied on the ceramic sheet by printing or the like to form an internal electrode pattern. The conductive paste may be printed by a screen printing method or a gravure printing method, but the present invention is not limited thereto.

A ceramic sheet on which the internal electrode pattern is printed may be laminated and a ceramic sheet on which an internal electrode pattern is not printed may be laminated on the upper and lower ceramic sheets to form a laminate including internal electrodes 221 and 222 therein. At this time, the number of stacked ceramic sheets on which the internal electrode pattern is printed can be adjusted according to the capacity of the multilayer ceramic capacitor. The ceramic sheet on which the internal electrode pattern is not printed becomes the cover portion 212 disposed on the upper and lower portions of the body 210.

Thereafter, the body 210 can be formed by pressing and firing the laminate.

Referring to FIG. 8, after the body 210 is formed, a first electrode layer 250 including TiN is formed on the entire surface of the body 210 by ALD.

Referring to FIG. 9, a second electrode layer 232 and a second electrode layer 242 are formed on a portion of the body where the first electrode layer 250 is formed, on which the first and second external electrodes are to be formed.

For example, the second electrode layer can be formed by applying and baking a paste containing a conductive metal and glass.

Further, after the paste in which the metal particles are dispersed in the base resin is applied, the second electrode layer can be formed by drying and curing.

The second electrode layer can be formed by applying a paste in which a low melting point metal having a melting point lower than the curing temperature of the metal particles and the base resin is dispersed in the base resin, followed by drying and curing.

Referring to FIG. 10, the exposed portions of the first electrode layer 250 are etched and removed from the body having the second electrode layers 232 and 242 to form first electrode layers 231 and 232, The multilayer ceramic capacitor can be completed by forming the first and second external electrodes 230 and 240 including the second electrode layers 232 and 242.

Since the second electrode layers 232 and 242 function as a passivation, the exposed portions of the first electrode layer 250 can be etched and removed without forming a separate protective layer.

In addition, the etching may be dry etching or wet etching.

Thereafter, a step of forming a plating layer on the first and second external electrodes 230 and 240 may be additionally performed, but the present invention is not limited thereto.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

It will be apparent to those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. something to do.

100: Multilayer Ceramic Capacitor
110: Body
111: dielectric layer
112: cover layer
121, 122: internal electrodes
130, 140: external electrode
131: first electrode layer
132: second electrode layer

Claims (16)

A body including a dielectric layer and an internal electrode, and an external electrode disposed on one surface of the body,
The external electrode
A first electrode layer disposed on one side of the body and contacting the internal electrode and including titanium nitride (TiN); And a second electrode layer disposed on the first electrode layer.
The method according to claim 1,
Wherein the first electrode layer is formed by an atomic layer deposition method.
The method according to claim 1,
Wherein the thickness of the first electrode layer is 10 to 500 nm.
The method according to claim 1,
The body includes first and second surfaces opposed to each other, third and fourth surfaces connected to the first and second surfaces and opposed to each other, a second surface coupled to the first and second surfaces, And fifth and sixth surfaces facing each other,
Wherein the internal electrodes include first and second internal electrodes alternately arranged such that one end of the internal electrode is exposed through the third and fourth surfaces with the dielectric layer interposed therebetween,
Wherein the external electrodes are disposed on the third and fourth surfaces of the body and include first and second external electrodes respectively connected to the first and second internal electrodes.
5. The method of claim 4,
The first and second external electrodes may include a connection portion formed on the third and fourth surfaces of the body, a band portion extending from the connection portion to portions of the first, second, fifth, and sixth surfaces of the body, And an edge portion where the connection portion and the band portion are in contact with each other,
Wherein t2 / t1 is 0.9 or more, wherein the thickness of the connecting portion of the first electrode layer is t1 and the thickness of the corner portion of the first electrode layer is t2.
The method according to claim 1,
Wherein the second electrode layer is a fired electrode including a conductive metal and a glass.
The method according to claim 6,
Lt; RTI ID = 0.0 > Cu. ≪ / RTI >
The method according to claim 1,
Wherein the second electrode layer is a resin-based electrode including a plurality of metal particles and a base resin.
9. The method of claim 8,
Wherein the metal particles are at least one of Cu, Ni and Ag.
The method according to claim 1,
Wherein the second electrode layer includes a plurality of metal particles, a conductive connection portion surrounding the plurality of metal particles, a base resin, and an intermetallic compound formed at an interface between the first electrode layer and the conductive connection portion.
11. The method of claim 10,
Wherein the metal particles are at least one of Cu, Ni, Ag, Ag coated Cu, and Sn coated Cu.
The method according to claim 1,
Wherein the external electrode further comprises a plating layer formed on the second electrode layer.
Preparing a body including a dielectric layer and an internal electrode;
Forming a first electrode layer including titanium nitride (TiN) on an entire surface of the body by an atomic layer deposition method;
Forming a second electrode layer on a portion of the body where the first electrode layer is formed, on which the first and second external electrodes are to be formed; And
And etching the exposed portion of the first electrode layer in the body having the second electrode layer to remove the exposed portion.
14. The method of claim 13,
Wherein the second electrode layer is formed by applying and firing a paste containing a conductive metal and a glass.
14. The method of claim 13,
Wherein the second electrode layer is formed by applying a paste in which metal particles are dispersed to a base resin, and then drying and curing the paste.
14. The method of claim 13,
Wherein the second electrode layer is formed by applying a paste in which a low-melting metal having a melting point lower than a curing temperature of the metal particles and the base resin is dispersed in a base resin, and then drying and curing the paste.

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