KR20200047502A - Capacitor component - Google Patents

Abstract

A capacitor component according to one embodiment of the present invention comprises: a body including a dielectric layer and first and second internal electrodes alternately disposed in a first direction with the dielectric layer therebetween; and first and second external electrodes respectively disposed at both ends in a second direction perpendicular to the first direction in the body. An amorphous secondary phase is disposed at an interface between the first and second internal electrodes and the dielectric layer. In the cross section of the first and second directions of the body, when defining the total length of the amorphous secondary phase disposed at the boundary between the first or second internal electrode and the dielectric layer as ls and the length of the first or second internal electrode as le, ls/le is greater than 0.02 and less than 0.07.

Description

Capacitor component {CAPACITOR COMPONENT}

The present invention relates to capacitor components.

Multi-layered ceramic capacitors (MLCCs), one of capacitor components, include imaging devices such as liquid crystal displays (LCDs) and plasma display panels (PDPs), computers, smartphones, and It is a capacitor in the form of a chip mounted on a printed circuit board of various electronic products such as a mobile phone to charge or discharge electricity.

Such a multilayer ceramic capacitor may be used as a component of various electronic devices due to its small size, high volume, and easy mounting. As various electronic devices such as computers and mobile devices have been miniaturized and outputted, demands for miniaturization and high capacity for multilayer ceramic capacitors are increasing.

In order to simultaneously achieve miniaturization and high capacity of the multilayer ceramic capacitor, it is necessary to increase the number of layers by making the thickness of the dielectric layer and the internal electrode thin. 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 the withstand voltage characteristics, and the quality and yield may be lowered due to an increase in defects in insulation resistance (IR) of the dielectric layer. .

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

One aspect of the present invention, a body including a dielectric layer and the 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 the 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. In the cross section of the first and second directions of the body, the total length of the amorphous secondary phase disposed at the boundary 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 ratio of ℓs / ℓe of 0.02 or more and 0.07 or less is provided.

As one of the various effects of the present invention, there is an effect that can provide a capacitor component having excellent withstand voltage characteristics.

However, various and advantageous advantages and effects of the present invention are not limited to the above, and may be more easily understood in the process of describing the specific embodiment of the present invention.

1 is a perspective view schematically showing a capacitor component according to an embodiment of the present invention.
2 is a cross-sectional view taken along line II` in FIG. 1.
3 is an enlarged view of part A of FIG. 2.
4 is a partially enlarged view schematically showing the inside of a multilayer ceramic capacitor according to an embodiment 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 may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below. Moreover, the embodiment of this invention is provided in order to fully describe this invention to those skilled in the art. Accordingly, the shape and size of elements in the drawings may be exaggerated for a clearer description, and elements indicated by the same reference numerals in the drawings are the same elements.

In addition, in order to clearly describe the present invention in the drawings, parts irrelevant to the description are omitted, and thicknesses are enlarged to clearly express various layers and regions, and components having the same function within the scope of the same idea have the same reference. It is explained using a sign. Furthermore, in the specification, when a part “includes” a certain component, this means that other components may be further included rather than excluding other components unless specifically stated to the contrary.

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

Capacitor parts

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

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

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

The specific shape of the body 110 is not particularly limited, but as shown, the body 110 may be formed in a hexahedral shape or a similar shape. Due to the shrinkage of the ceramic powder contained in the body 110 during the firing process, the body 110 may have a substantially hexahedral shape, although not a hexahedral shape having a complete straight line.

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

The plurality of dielectric layers 111 forming the body 110 is in a fired state, and boundaries between adjacent dielectric layers 111 may be integrated to a degree that it is 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, and may be, for example, barium titanate (BaTiO ₃ ) powder. As a material for forming the dielectric layer 111, various ceramic additives, organic solvents, plasticizers, binders, dispersants, etc. may be added to powders such as barium titanate (BaTiO ₃ ) according to the purpose of the present invention.

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

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

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

At this time, 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.

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

The conductive paste may be printed using a screen printing method or a gravure printing method, and the present invention is not limited thereto.

The thickness te of the first and second internal electrodes 121 and 122 is not 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 thicknesses of the first and second internal electrodes 121 and 122 are scanned by scanning electron microscopy (SEM) on the cross section of the length and thickness direction (LT) of the body 110 as shown in FIG. 2. Can be measured.

For example, as shown in FIG. 2, the length and thickness direction (LT) cross-sections cut in the center of the width (W) direction of the body 110 are extracted from an image scanned with a scanning electron microscope (SEM). For the first and second internal electrodes 121 and 122, the average value may be measured by measuring the thickness at 30 points equally spaced in the longitudinal direction.

The equally spaced 30 points may be measured in a capacity forming unit 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 the capacitor component is determined by the insulation resistance (IR) of the chip. In particular, the resistance of the interface between the dielectric layer and the internal electrode is an element that determines 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, it is possible to improve the withstand voltage characteristics of the capacitor component by improving the insulation resistance of the entire chip, and to improve the breakdown voltage (BDV) and reliability.

The total length of the amorphous secondary phase disposed at the boundary between the first or second internal electrode and the dielectric layer in the first and second cross-sections of the body 110, that is, in the length and thickness (LT) cross-sections of the body, When defining the length of ℓs, the first or second internal electrode 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 for improving the breakdown voltage. On the other hand, if ℓs / ℓe is more than 0.07, the capacity may not only be reduced due to the excessive amorphous secondary phase, but rather, the reliability may be deteriorated due to non-uniform plastic dispersion of the dielectric.

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

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

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

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

The equally spaced 30 points may be measured in a capacity forming unit which means a region where the first and second internal electrodes 121 and 122 overlap each other.

At this time, 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 thinned.

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 can 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 phase 113 is disposed in the groove portion.

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

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

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

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

When the inner electrodes 121 and 122 include Sn, Sn has a lower melting point than Ni, and does not provide a solid solution to Ni, and has good wettability with Ni, thereby suppressing the growth of the inner electrode to suppress the growth of the inner electrode Can be formed thin. Since Sn has a lower melting point than Ni, it can be included in the amorphous secondary phase 113 by moving ahead of Ni to the interface between the dielectric layers 111 and the internal electrodes 121 and 122 when firing. Further, as the firing progresses, both the Sn and Ni may be included in the amorphous secondary phase 113.

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

Meanwhile, the thickness td of the dielectric layer 111 is not particularly limited.

However, when the dielectric layer is formed to have 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 (Grain) per layer of the dielectric layer is limited, so it is difficult to secure the withstand voltage characteristics There is a problem that the quality and yield are lowered due to an increase in defects in insulation resistance (IR) of the dielectric layer.

According to an embodiment of the present invention, when the 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, the insulation resistance of the entire chip is improved to improve the capacitor Since the withstand voltage characteristics of the component can be improved and the breakdown voltage (BDV) and reliability can be improved, sufficient withstand voltage characteristics can be secured even when the thickness td of the dielectric layer is 0.4 μm or less.

Therefore, when the thickness td of the dielectric layer 111 is 0.4 μm or less, the withstand voltage characteristics, breakdown voltage (BDV), and reliability improvement effect 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 a 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, a cross section of the length and thickness direction (LT) cut in the center of the width direction of the body 110 is attached to an arbitrary dielectric layer extracted from an image scanned with a scanning electron microscope (SEM). With respect to it, the average value can be measured by measuring the thickness at 30 equally spaced points in the longitudinal direction.

The equally spaced 30 points may be measured in a capacity forming unit which means a region where the first and second internal electrodes 121 and 122 overlap each other.

The outer electrodes 131 and 132 are disposed on the body 110 and are connected to the inner electrodes 121 and 122. As illustrated in FIG. 2, the first and second external electrodes 131 and 132 may be respectively connected to the first and second internal electrodes 121 and 122, respectively. In this embodiment, the structure in which the capacitor component 100 has two external electrodes 131 and 132 is described, but the number and shape of the external electrodes 131 and 132 are the shapes of the internal electrodes 121 and 122, It may change for other purposes.

Meanwhile, 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, structural stability, etc., and may further have a multi-layer 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.

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

For more specific examples of the plating layers 131b and 132b, the plating layers 131b and 132b may be Ni plating layers or Sn plating layers, and Ni plating layers and Sn plating layers may be sequentially formed on the electrode layers 131a and 132a. It may also include a plurality of Ni plating layers and / or a plurality of Sn plating layers.

Meanwhile, the size of the capacitor component 100 is not particularly limited.

However, in order to simultaneously achieve miniaturization and high capacity, since the number of stacks must be increased by reducing the thickness of the dielectric layer and the internal electrode, the withstand voltage characteristic according to the present invention in a capacitor component of size 0402 (0.4mm × 0.2mm) or less, BDV ( Breakdown Voltage) and reliability improvement effect may be more remarkable.

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 embodiments of the present invention have been described in detail above, the present invention is not limited by the above-described embodiments and the accompanying drawings, and is intended to be limited by the appended claims. Accordingly, various forms of substitution, modification, and modification will be possible by those skilled in the art without departing from the technical spirit of the present invention as set forth in the claims, and this also belongs to the scope of the present invention. something to do.

100: capacitor parts
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;
It includes; first and second external electrodes disposed on both end surfaces of the second direction perpendicular to the first direction in the body;
An amorphous secondary phase is disposed at an interface between the first and second internal electrodes and the dielectric layer,
In the first and second cross-sections of the body, the total length of the amorphous secondary phase disposed at the boundary between the first or second inner electrode and the dielectric layer is ls, and the length of the first or second inner electrode When ℓe is defined, ℓs / ℓe is a capacitor component of 0.02 or more and 0.07 or less.
According to claim 1,
The amorphous secondary phase is a capacitor component disposed in the groove 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 containing at least one of Ni and Sn.
According to claim 4,
The amorphous secondary phase capacitor component further comprises S.
According to claim 1,
The dielectric layer has a thickness of 0.4 µm or less capacitor component.
According to claim 1,
The first and second internal electrode thickness of the capacitor component is less than 0.4㎛.
According to claim 1,
A capacitor part including a dielectric layer is disposed at both ends of the first direction of the body, 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 T and the length of the body in the second direction is L, T is 0.4 mm or less and L is 0.2 mm or less.

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