KR102351184B1 - Capacitor component - Google Patents

Abstract

A capacitor component according to an embodiment of the present invention includes: a body including a dielectric layer and first and second internal electrodes alternately disposed in a first direction with the dielectric layer interposed therebetween; and first and second external electrodes respectively disposed on both end surfaces of the body in a second direction perpendicular to the first direction, wherein an amorphous secondary phase is disposed at an interface between the first and second internal electrodes and the dielectric layer and, in the first and second cross-sections of the body, the total length of the amorphous secondary phase disposed at the boundary line between the first or second internal electrode and the dielectric layer is ℓs, the first or second internal electrode When the length of is defined as ℓe, ℓs/ℓe is 0.02 or more and 0.07 or less.

Description

Capacitor Component {CAPACITOR COMPONENT}

The present invention relates to capacitor components.

Multi-Layered Ceramic Capacitors (MLCCs), one of the capacitor components, are used in imaging devices such as liquid crystal displays (LCDs) and plasma display panels (PDPs), computers, smartphones and others. It is a chip-type capacitor that is installed on the printed circuit board of various electronic products such as mobile phones and plays a role of charging or discharging electricity.

Such multilayer ceramic capacitors may be used as components of various electronic devices due to their small size, high capacity, and easy mounting. As various electronic devices such as computers and mobile devices are miniaturized and have high output, the demand for miniaturization and high capacity multilayer ceramic capacitors is increasing.

In order to simultaneously achieve miniaturization and high capacity of the multilayer ceramic capacitor, it is necessary to increase the number of stacks by reducing the thickness of the dielectric layer and the internal electrode. Currently, the thickness of the dielectric layer has reached the level of about 0.6 μm, and thinning continues.

However, when the dielectric layer is formed to a thickness of less than 0.6 μm, there is a problem in that it is difficult to secure withstand voltage characteristics, and the deterioration of the insulation resistance (IR) of the dielectric layer increases, so that the quality and yield are lowered. .

One object of the present invention is to provide a capacitor component having excellent withstand voltage characteristics.

One aspect of the present invention may include a body including a dielectric layer and first and second internal electrodes alternately disposed in a first direction with the dielectric layer interposed therebetween; and first and second external electrodes respectively disposed on both end surfaces of the body in a second direction perpendicular to the first direction, wherein an amorphous secondary phase is disposed at an interface between the first and second internal electrodes and the dielectric layer and, in the cross section in the first and second directions of the body, the total length of the amorphous secondary phase disposed at the boundary line between the first or second internal electrode and the dielectric layer is ℓs, the first or second internal electrode When the length of is defined as ℓe, a capacitor component having a ℓs/ℓe ratio of 0.02 or more and 0.07 or less is provided.

As one effect among various effects of the present invention, it is possible to provide a capacitor component having excellent withstand voltage characteristics.

However, various and beneficial advantages and effects of the present invention are not limited to the above, and will be more easily understood in the course of describing specific embodiments of the present invention.

1 is a perspective view schematically illustrating a capacitor component according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along line II′ of FIG. 1 .
FIG. 3 is an enlarged view of part A of FIG. 2 .
4 is a partially enlarged view schematically illustrating the inside of a multilayer ceramic capacitor according to an exemplary embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to specific embodiments and the accompanying drawings. However, the embodiment of the present invention may be modified in 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 in order to more completely explain the present invention to those skilled in the art. Accordingly, the shapes and sizes of elements in the drawings may be exaggerated for clearer description, and elements indicated by the same reference numerals in the drawings are the same elements.

And in order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted, and the thickness is enlarged to clearly express various layers and regions, and components having the same function within the scope of the same idea are referred to as the same. It is explained using symbols. Furthermore, throughout the specification, when a part "includes" a certain element, it means that other elements may be further included, rather than excluding other elements, unless otherwise stated.

In the drawings, the X direction may be defined as a second direction or length direction, the Y direction may be defined as a third direction or width direction, and the Z direction may be defined as a first direction, a stacking direction, or a thickness direction.

capacitor parts

1 is a perspective view schematically illustrating a capacitor component according to an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line II′ of FIG. 1 . FIG. 3 is an enlarged view of part A of FIG. 2 .

1 to 3 , in the capacitor component 100 according to the exemplary embodiment of the present invention, a dielectric layer 111 and first and second interiors alternately disposed in a first direction (Z direction) with the dielectric layer interposed therebetween a body 110 including electrodes 121 and 122; In the body, first and second external electrodes 131 and 132 are respectively disposed on both end surfaces 3 and 4 in the second direction (X direction) perpendicular to the first direction (Z direction); An amorphous secondary phase 113 is disposed at the interface between the first and second internal electrodes 121 and 122 and the dielectric layer 111, and in the cross section of the body 110 in the first and second directions, When the total length of the amorphous secondary phase 113 disposed at the boundary line between the first or second internal electrode and the dielectric layer is defined as ℓs and the length of the first or second internal electrode is defined as ℓe, ℓs/ℓe ratio It is 0.02 or more and 0.07 or less.

In the body 110 , a dielectric layer 111 and internal electrodes 121 and 122 are alternately stacked.

Although the specific shape of the body 110 is not particularly limited, as shown, the body 110 may have a hexahedral shape or a shape similar thereto. Due to the shrinkage of the ceramic powder included in the body 110 during the firing process, the body 110 may not have a perfectly straight hexahedral shape, but may have a substantially hexahedral shape.

The body 110 is connected to the first and second surfaces 1 and 2 facing each other in the thickness direction (Z direction), the first and second surfaces 1 and 2, and is connected to each other in the width direction (Y direction) The third and fourth surfaces 3 and 4 opposite to each other, the first and second surfaces 1 and 2 are connected, and the third and fourth surfaces 3 and 4 are connected to each other in the longitudinal direction (X direction). It may have opposing fifth and sixth surfaces 5 , 6 .

The plurality of dielectric layers 111 forming the body 110 are in a fired state, and the boundary between adjacent dielectric layers 111 can be integrated to the extent that it is difficult to check 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 capacitance can be obtained, and for example, barium titanate (BaTiO ₃ ) powder may be used. As a material for forming the dielectric layer 111 , various ceramic additives, organic solvents, plasticizers, binders, dispersants, etc. may be added to powder such as _{barium titanate (BaTiO 3 ) according to the purpose of the present invention.}

The upper and lower portions of the body 110, that is, both ends in the thickness direction (Z direction), may include a cover layer 112 formed by stacking dielectric layers on which internal electrodes are not formed, respectively. The cover layer 112 may serve to maintain reliability of the capacitor against external impact.

The thickness of the cover layer 112 does not need to be particularly limited. However, in order to more easily achieve miniaturization and high capacity of the capacitor component, the thickness of the cover layer 112 may be 20 μm or less.

Next, the internal electrodes 121 and 122 are alternately stacked with dielectric layers, and may include first and second internal electrodes 121 and 122 . The first and second internal electrodes 121 and 122 are alternately disposed to face each other with the dielectric layer 111 constituting the body 110 interposed therebetween, and the third and fourth surfaces 3 and 4 of the body 110 . ) can be exposed respectively.

In this case, the first and second internal electrodes 121 and 122 may be electrically separated from each other by the dielectric layer 111 disposed in the middle.

Materials forming the first and second internal electrodes 121 and 122 are not particularly limited, and for example, noble metal materials such as palladium (Pd), palladium-silver (Pd-Ag) alloy, and nickel (Ni) and copper It may be formed using a conductive paste made of at least one material of (Cu).

The method for printing the conductive paste may use a screen printing method or a gravure printing method, but the present invention is not limited thereto.

The thickness te of the first and second internal electrodes 121 and 122 does not need to be particularly limited. However, the thickness te of the first and second internal electrodes 121 and 122 may be 0.4 μm or less in order to more easily achieve miniaturization and high capacity of the capacitor component.

The thickness te of the first and second internal electrodes 121 and 122 may mean an average thickness of the first and second internal electrodes 121 and 122 .

The average thickness of the first and second internal electrodes 121 and 122 is obtained by scanning an image of the length and thickness direction (LT) cross-section of the body 110 with a scanning electron microscope (SEM) as shown in FIG. can be measured

For example, as shown in FIG. 2 , the length and thickness direction (LT) cross-sections cut from the central part in the width (W) direction of the body 110 are scanned with a scanning electron microscope (SEM, Scanning Eletron Microscope). With respect to the first and second internal electrodes 121 and 122 of , the thickness may be measured at 30 equal intervals in the longitudinal direction to measure the average value.

The 30 points at equal intervals may be measured in the capacitor forming part, which means a region where the first and second internal electrodes 121 and 122 overlap each other.

An amorphous secondary phase 113 is disposed at the interface between the first and second internal electrodes 121 and 122 and the dielectric layer 111 .

The withstand voltage of capacitor components is influenced by the insulation resistance (IR) of the chip. In particular, the resistance of the interface between the dielectric layer and the internal electrode is a factor that influences the insulation resistance of the entire chip.

In the present invention, an amorphous secondary phase 113 having high resistance is disposed at the interface between the first and second internal electrodes 121 and 122 and the dielectric layer 111 . Accordingly, by improving the insulation resistance of the entire chip, the withstand voltage characteristics of the capacitor component can be improved, and the BDV (Breakdown Voltage) and reliability can be improved.

The total length of the amorphous secondary phase disposed at the boundary line between the first or second internal electrode and the dielectric layer in the cross-section in the first and second directions of the body 110, that is, in the length and thickness direction (LT) cross-section of the body. When ℓs, the length of the first or second internal electrode is defined as ℓe, ℓs/ℓe is 0.02 or more and 0.07 or less.

When ℓs/ℓe is less than 0.02, it may be difficult to confirm the presence or absence of an amorphous secondary phase in the SEM image, and it may be difficult to secure sufficient insulation resistance required to improve withstand voltage. On the other hand, when ℓs/ℓe is greater than 0.07, the capacity may decrease due to an excessive amount of the amorphous secondary phase, but rather, there may be a problem in that reliability is reduced by inducing non-uniform plastic distribution of the dielectric.

Although not limited thereto, ℓs/ℓe may be adjusted by adjusting the content of the ceramic material included in the first and second internal electrodes 121 and 122 or the content of the additive included in the dielectric layer 111 .

Referring to FIG. 3 , ℓs means the sum of the lengths of all amorphous secondary phases 113 disposed on one boundary line between the internal electrodes 121 and 122 and the dielectric layer 111, and ℓe means the length of the one boundary line. can do. That is, ℓs in FIG. 3 is the sum of ℓs1 to ℓs4.

ℓs and ℓe may be measured by scanning an image of the length and thickness direction (L-T) cross-section of the body 110 with a scanning electron microscope (SEM), as shown in FIG. 2 .

For example, as shown in FIG. 2 , the internal electrode and dielectric layer extracted from the image scanned with a scanning electron microscope (SEM) of the length and thickness direction (LT) cross section cut from the central part of the body 110 in the width direction. For an arbitrary boundary line of , the average value can be measured by measuring the lengths of the inner electrode and the amorphous secondary phase at 30 points equally spaced in the longitudinal direction.

The 30 points at equal intervals may be measured in the capacitor forming part, which means a region where the first and second internal electrodes 121 and 122 overlap each other.

In this case, the amorphous secondary phase 113 may be disposed in the grooves of the first and second internal electrodes 121 and 122 .

Referring to FIG. 4 , it can be seen that the amorphous secondary phase 113 is mainly disposed in the grooves of the first and second internal electrodes 121 and 122 . Here, the groove portion of the first and second internal electrodes 121 and 122 may mean a portion in which the thickness of the first and second internal electrodes 121 and 122 is reduced.

As the amorphous secondary phase 113 is disposed in the groove portion, the instability of the interface between the dielectric layer 111 and the internal electrodes 121 and 122 may be lowered to improve adhesion between the dielectric layer and the internal electrode. However, it is necessary to note that it does not mean that all the amorphous secondary phases 113 are disposed in the groove portion.

The amorphous secondary phase 113 may include at least one of Mg, Al, Mn, V, and Dy.

This is because, when the amorphous secondary phase 113 includes at least one of Mg, Al, Mn, V, and Dy, the secondary phase may be more easily formed.

In addition, the amorphous secondary phase 113 may include at least one of Ni and Sn.

When the internal electrodes 121 and 122 include Ni, during sintering, Ni of the internal electrodes 121 and 122 moves to the interface and may be included in the amorphous secondary phase 113 .

When the internal electrodes 121 and 122 contain Sn, Sn has a lower melting point than Ni, does not form a solid solution in Ni, and has good wettability with Ni. can be formed thin. Since Sn has a lower melting point than Ni, during firing, it moves to the interface between the dielectric layer 111 and the internal electrodes 121 and 122 before Ni and may be included in the amorphous secondary phase 113 . In addition, both Sn and Ni may be included in the amorphous secondary phase 113 as sintering progresses.

In addition, the amorphous secondary phase 113 may include at least one of Ni and Sn, and may further include S. For example, when a conductive paste including Ni powder coated with S as an internal electrode forming material is used, S may also be included in the amorphous secondary phase 113 .

Meanwhile, the thickness td of the dielectric layer 111 does not need to be particularly limited.

However, when the dielectric layer is thinly formed to a thickness of less than 0.6 μm, especially when the thickness (td) of the dielectric layer is 0.4 μm or less, the number of dielectric particles that can exist per dielectric layer is limited, so it is difficult to secure withstand voltage characteristics. There may be problems such as a decrease in quality and yield due to an increase in insulation resistance (IR) deterioration of the dielectric layer.

According to an embodiment of the present invention, when the amorphous secondary phase 113 with high resistance is disposed at the interface between the first and second internal electrodes 121 and 122 and the dielectric layer 111, the insulation resistance of the entire chip is improved to improve the capacitor Since it is possible to improve the withstand voltage characteristics of components, and to improve BDV (Breakdown Voltage) and reliability, sufficient withstand voltage characteristics can be secured even when the thickness (td) of the dielectric layer is 0.4 μm or less.

Accordingly, when the thickness td of the dielectric layer 111 is 0.4 μm or less, the effect of improving the withstand voltage characteristics, BDV (Breakdown Voltage) and reliability according to the present invention may be more remarkable.

The thickness td of the dielectric layer 111 may mean an average thickness of the dielectric layer 111 disposed between the first and second internal electrodes 121 and 122 .

The average thickness of the dielectric layer 111 may be measured by scanning an image of the length and thickness direction (L-T) cross-section of the body 110 with a scanning electron microscope (SEM) as shown in FIG. 2 .

For example, as shown in FIG. 2, the length and thickness direction (LT) cross-sections cut from the central part of the body 110 in the width direction are scanned with a scanning electron microscope (SEM) to any dielectric layer extracted from the image. For this, the average value can be measured by measuring the thickness at 30 points equally spaced in the longitudinal direction.

The 30 points at equal intervals may be measured in the capacitor forming part, which means a region where the first and second internal electrodes 121 and 122 overlap each other.

The external electrodes 131 and 132 are disposed on the body 110 and are connected to the internal electrodes 121 and 122 . As shown in FIG. 2 , first and second external electrodes 131 and 132 respectively connected to the first and second internal electrodes 121 and 122 may be included. Although the structure in which the capacitor component 100 has two external electrodes 131 and 132 is described in this embodiment, the number and shape of the external electrodes 131 and 132 depends on the shape of the internal electrodes 121 and 122 or the like. It may be changed according to other purposes.

On the other hand, the external electrodes 131 and 132 may be formed using any material as long as they have electrical conductivity, such as metal, and specific materials may be determined in consideration of electrical characteristics and structural stability, and further may have a multi-layered structure. have.

For example, the external electrodes 131 and 132 may include electrode layers 131a and 132a disposed on the body 110 and plating layers 131b and 132b formed on the electrode layers 131a and 132a.

As a more specific example of the electrode layers 131a and 132a, the electrode layers 131a and 132a may be fired electrodes including a conductive metal and glass, and the conductive metal may be Cu. In addition, the electrode layers 131a and 132a may be resin-based electrodes including a plurality of metal particles and a conductive resin.

As a more specific example of the plating layers 131b and 132b, the plating layers 131b and 132b may be a Ni plating layer or a Sn plating layer, and a Ni plating layer and a Sn plating layer may be sequentially formed on the electrode layers 131a and 132a. and may include a plurality of Ni plating layers and/or a plurality of Sn plating layers.

Meanwhile, the size of the capacitor component 100 does not need to be particularly limited.

However, in order to achieve miniaturization and high capacity at the same time, it is necessary to increase the number of stacks by making the thickness of the dielectric layer and the internal electrode thin. Therefore, the withstand voltage characteristics, BDV ( breakdown voltage) and reliability improvement effect may be more significant.

Accordingly, when defining the length of the capacitor component in the first direction as T and the length of the body in the second direction as L, T may be 0.4 mm or less, and L may be 0.2 mm or less. That is, it may be a capacitor component having a size of 0402 (0.4mm×0.2mm) or less.

Although the embodiment of the present invention has been described in detail above, the present invention is not limited by the above-described embodiment and the accompanying drawings, but is intended to be limited by the appended claims. Therefore, various types of substitution, modification and change will be possible by those skilled in the art within the scope not departing from the technical spirit of the present invention described in the claims, and it is also said that it falls within the scope of the present invention. something to do.

100: capacitor part
110: body
121, 122: internal electrode
111: dielectric layer
112: cover layer
113: amorphous secondary phase
131, 132: external electrode

Claims (9)

a body including a dielectric layer and first and second internal electrodes alternately disposed in a first direction with the dielectric layer interposed therebetween;
first and second external electrodes respectively disposed on both end surfaces of the body in a second direction perpendicular to the first direction; and
The first and second internal electrodes include at least one of palladium (Pd), palladium-silver (Pd-Ag), nickel (Ni), and copper (Cu),
An amorphous secondary phase is disposed at an interface between the first and second internal electrodes and the dielectric layer,
In the cross-sections in the first and second directions of the body, the total length of the amorphous secondary phase disposed at the boundary line between the first or second internal electrode and the dielectric layer is ℓs, the length of the first or second internal electrode When ℓe is defined as ℓe, ℓs/ℓe is a capacitor component of 0.02 or more and 0.07 or less.
According to claim 1,
and the amorphous secondary phase is disposed in the grooves of the first and second internal electrodes.
According to claim 1,
The amorphous secondary phase is a capacitor component comprising at least one of Mg, Al, Mn, V, and Dy.
According to claim 1,
The amorphous secondary phase is a capacitor component comprising at least one of Ni and Sn.
5. The method of claim 4,
The amorphous secondary phase is a capacitor component further comprising S.
According to claim 1,
The thickness of the dielectric layer is 0.4㎛ or less capacitor component.
According to claim 1,
The thickness of the first and second internal electrodes is 0.4 μm or less.
According to claim 1,
A cover part including a dielectric layer is disposed on both ends of the body in the first direction, and the thickness of the cover part is 20 µm or less.
According to claim 1,
When the length of the capacitor component in the first direction is defined as T and the length of the body in the second direction is defined as L, T is 0.4 mm or less, and L is 0.2 mm or less.

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