KR101522768B1 - Inductor and method for manufacturing the same - Google Patents

Abstract

An inductor according to an embodiment of the present invention includes an element body having a stack of a plurality of sheets and a gap layer interposed between the sheets of the element body and made of a metal- . ≪ / RTI >

Description

≪ Desc / Clms Page number 1 > INDUCTOR AND METHOD FOR MANUFACTURING THE SAME

The present invention relates to an inductor and a method of manufacturing the same, and more particularly, to an inductor having a small change in inductance due to current application, and a manufacturing method thereof.

Multilayer power inductors are mainly used in power circuits such as DC-DC converters in portable electronic devices. They are used for high current applications because they have the feature of suppressing the magnetic saturation of inductors in material and structure. The stacked type power inductor has a disadvantage in that the inductance changes largely due to current application compared to the wound type power inductor. However, the stacked type power inductor has advantages of miniaturization and thinning, and can meet the trend of electronic components in recent years.

The multilayered power inductor is manufactured by stacking magnetic sheets on which internal electrodes are printed to form a device body, and then forming external electrodes electrically connected to the internal electrodes on both end surfaces of the device body. Here, the magnetic sheets are made of a composite material containing ferrite powder. In addition, in order to reduce a change in inductance with respect to an external current, a gap layer made of a nonmagnetic material may be inserted into the element body, and the gap layer may be provided to cut off the magnetic flux.

Generally, the gap layer is made of ZnCu ferrite nonmagnetic material. However, in this case, nickel (Ni) contained in the NiZnCu ferrite as the element body material is diffused into the gap layer, and the Zn component of the gap layer is diffused into the element body, so that the thickness of the gap layer becomes substantially thin As a result, the DC-bias characteristic of the inductor is remarkably deteriorated.

Korean Patent Publication No. 2012-104785

SUMMARY OF THE INVENTION It is an object of the present invention to provide an inductor capable of improving inductance characteristics and a manufacturing method thereof.

An object of the present invention is to provide an inductor having a structure capable of reducing a change in inductance with respect to an external current and a method of manufacturing the inductor.

An inductor according to the present invention includes a device body having a stack of a plurality of sheets and a gap layer interposed between the sheets of the device body and made of a metal-glass composite material.

According to an embodiment of the present invention, the metal of the metal-glass composite material may include iron-based crystalline metal particles.

According to an embodiment of the present invention, the metal of the metal-glass composite may include Fe-Si-Cr crystalline metal particles.

According to an embodiment of the present invention, the metal of the metal-glass composite material may have a maximum particle diameter of 10 mu m or less.

According to an embodiment of the present invention, the glass may have a -Si-O-Si-O- structure as a main bonding structure.

According to an embodiment of the present invention, the glass content of the metal-glass composite material may be 45 wt% to 75 wt% with respect to the composite material.

According to an embodiment of the present invention, the metal content of the metal-glass composite material may be 25 wt% or more with respect to the composite material.

According to an embodiment of the present invention, an internal electrode disposed on the sheets and an external electrode electrically connected to the internal electrode at both end surfaces of the element body may be further included.

A method of manufacturing an inductor according to the present invention includes the steps of preparing a metal-glass composite material sheet for manufacturing a gap layer by filming a metal-glass composite material composed of metal particles and glass, fabricating magnetic sheet sheets having internal electrodes formed on the surface thereof, - forming a multilayer body by inserting a glass composite sheet between the magnetic sheets to manufacture an element body, and forming external electrodes electrically connected to the internal electrodes at both ends of the element body.

The inductor according to the present invention has a structure in which a metal having a relatively high saturation magnetization value is used as the material of the gap layer. Therefore, compared with the case of manufacturing the gap layer with the ferrite material, the inductance change rate due to current application can be greatly reduced, It is possible to prevent degradation of the chip characteristics of the inductor due to the diffusion phenomenon of the metal.

1 is a view illustrating an inductor according to an embodiment of the present invention.
FIG. 2 is a plan view showing the gap layer shown in FIG. 1; FIG.
3 is a photograph showing a metal-glass composite sheet for fabricating a gap layer of an inductor according to an embodiment of the present invention.
4 is a graph showing bias-TCL characteristics of an inductor according to an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. These embodiments are provided so that the disclosure of the present invention is complete and that those skilled in the art will fully understand the scope of the present invention. Like reference numerals designate like elements throughout the specification.

The terms used herein are intended to illustrate embodiments and are not intended to limit the invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. It is to be understood that the terms 'comprise', and / or 'comprising' as used herein may be used to refer to the presence or absence of one or more other components, steps, operations, and / Or additions.

In addition, the embodiments described herein will be described with reference to cross-sectional views and / or plan views, which are ideal illustrations of the present invention. In the drawings, the thicknesses of the films and regions are exaggerated for an effective description of the technical content. The shape of the illustration may be modified by following and / or by tolerance or the like. Accordingly, the embodiments of the present invention are not limited to the specific forms shown, but also include changes in the shapes that are generated according to the manufacturing process. For example, the etched area shown at right angles may be rounded or may have a shape with a certain curvature.

FIG. 1 is a view showing an inductor according to an embodiment of the present invention, and FIG. 2 is a plan view showing a metal-glass sheet for fabricating the gap layer shown in FIG.

Referring to FIGS. 1 and 2, an inductor 100 according to an embodiment of the present invention may include a device body 110, an electrode structure 120, and a gap layer 130.

The element body 110 may have a multi-layer structure consisting of a plurality of sheets 112. As the sheets 112, a plurality of non-magnetic ceramic insulating sheets or a ferrite magnetic sheet or the like may be used. Each of the sheets 112 may be a sheet made of a ferrite-based magnetic material. More specifically, each of the sheets 112 may be a magnetic sheet made of Ni-Zn-Cu ferrite. The Ni-Zn-Cu ferrite may be ferrite containing Fe 2 O 3, NiO, ZnO, CuO, or the like selectively.

The electrode structure 120 may have an internal electrode 122 provided inside the device body 110 and an external electrode 124 provided outside the device body 110. The internal electrode 122 may be a silver (Ag) or other metal circuit pattern. The external electrode 124 may be for electrically connecting the inductor 100 to an external electronic device (not shown). The external electrodes 124 may be provided at both ends of the element body 110 while being electrically connected to the internal electrodes 122. The external electrode 124 may be formed of a metal layer as an external terminal and a plating layer of nickel (Ni) or tin (Sn) formed by performing a plating process on the metal layer.

The gap layer 130 may be provided between the sheets 112 inside the element body 110. The gap layer 130 may be disposed between the sheets 112 in a direction parallel to the sheets 112 to divide the element body 110 into a plurality of regions. At least one of the gap layers 130 may be disposed. When the plurality of gap layers 130 are provided, the gap layers 130 may be spaced apart from each other in the device body 110 . The magnetic field generated in each of the regions is blocked by the gap layer 130 so that the flow of the magnetic field between the regions can be minimized.

The gap layer 130 may be made of a composite material made of metal particles and glass (hereinafter referred to as a 'metal-glass composite material'). In the case of the gap layer 130 made of a metal-glass composite material as described above, the magnetic permeability of the element body 110 according to the function of the gap layer 130 is lowered and the magnetic permeability of the metal magnetic material contained in the gap layer 130 The rate of change of the inductance value due to the application of the current can be reduced due to the saturation magnetization value Ms. However, in order to use the metal as the material of the gap layer 130, glass is added to the metal, so that the sinterability of the composite material is secured In addition, functions such as prevention of oxidation and securing of insulation can be controlled.

In such a metal-glass composite, the content of the glass may be very important. The content of the glass should be at least about 45 wt% and more preferably at least about 50 wt% with respect to the metal-glass composite material, so that a proper permeability can be ensured and the function as the gap layer 130 can be realized. When the content of the glass is less than 45 wt% with respect to the composite material, the permeability may become 10 or more, so it may be very difficult to match the permeability of the inductor 100. Also, the metal should be at least about 25 wt% relative to the metal-glass composite. When the content of the metal is less than 25 wt% with respect to the composite material, the permeability becomes 3 or less, which may not contribute to the saturation magnetization characteristic of the metal at all. Accordingly, considering the function of the gap layer 130 and the supplement of the saturation magnetization value, the content of the glass to the metal-glass composite material may be preferably about 45 wt% to 75 wt%. The permeability of the inductor 100 according to the content of the glass relative to the metal-glass composite material is shown in Table 1 below.

No Glass content (wt%) Investment ratio One 30 15 2 45 7 to 10 3 60 5 ~ 7 4 75 3 to 5 5 80 Less than 3

It is also preferable that Fe-Si-Cr crystalline metal having a maximum diameter of 10 mu m is used as the metal particles of the metal-glass composite material. If the diameter of the metal particles exceeds 10 mu m, the thickness of the gap layer 130 becomes excessively large, and the possibility of electric short-circuiting between the internal electrode 122 and the gap layer 130 may be significantly increased have. In addition, the Fe-Si-Cr crystalline metal containing Cr is ensured in oxidation stability, and the Fe particles can be prevented from being oxidized even during the high-temperature firing step during the manufacturing process of the inductor 100 .

The gap layer 130 is formed by interposing a metal-glass sheet 131 formed by filming the metal-glass composite material between the sheets 112 of the element body 110, ) Can be manufactured by performing a heat treatment process such as firing. At this time, the metal-glass sheet 131 may be a product produced by filming a composite material in which the metal particles 132 are uniformly distributed in the glass-containing compound 134. The preferable particle diameters of the metal particles 132 may be as described above.

3 is a photograph showing a metal-glass composite sheet for fabricating a gap layer of an inductor according to an embodiment of the present invention. Referring to FIG. 3, a metal-glass composite sheet for manufacturing a gap layer according to an embodiment of the present invention is manufactured by casting a composite material of metal particles and a glass-containing compound to form a film. As described above, the gap layer 130 can be manufactured by inserting a desired number of sheets of the metal-glass composite sheet for fabricating the gap layer between the sheets 112 in the process of manufacturing the element body 110 of the inductor 100.

4 is a graph showing bias-TCL characteristics of an inductor according to an embodiment of the present invention. Referring to FIG. 4, when the inductor 100 of FIG. 1 is manufactured using the metal-glass composite sheet for fabricating a gap layer described above with reference to FIGS. 2 and 3, a metal having a high saturation magnetization value is used as a gap layer material , It can be confirmed that the rate of change of the inductance due to the application of the DC current can be greatly reduced. In addition, since the conventional ferrite-based gap layer is not used, it is possible to prevent the deterioration of the characteristics of the inductor chip due to the diffusion phenomenon.

As described above, the inductor 100 according to the embodiment of the present invention includes the gap layer 130 inserted between the sheets 112 in the element body 110 to perform the function of breaking the magnetic flux, . ≪ / RTI > In this case, since a metal having a relatively high saturation magnetization value can be used as the material of the gap layer 130, the rate of change of inductance due to the application of current can be greatly reduced. Moreover, since no ferrite material is used, It is possible to prevent the phenomenon that the chip characteristics of the inductor are lowered. Accordingly, since the inductor according to the present invention has a structure using a metal having a relatively high saturation magnetization value as the material of the gap layer, the rate of change in inductance due to current application is greatly reduced compared to the case where the gap layer is made of ferrite material And it is possible to prevent the deterioration of the chip characteristics of the inductor due to the diffusion phenomenon of the metal.

The foregoing detailed description is illustrative of the present invention. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation only as the same may be varied in scope or effect. Changes or modifications are possible within the scope. The foregoing embodiments are intended to illustrate the best mode contemplated for carrying out the invention and are not intended to limit the scope of the invention to those skilled in the art that are intended to encompass other modes of operation known in the art for utilizing other inventions such as the present invention, Various changes are possible. Accordingly, the foregoing description of the invention is not intended to limit the invention to the precise embodiments disclosed. It is also to be understood that the appended claims are intended to cover such other embodiments.

100: inductor
110: element body
112: sheets
122: internal electrode
124: external electrode
130: Gap layer
132: metal particles
134: Glass-containing compound

Claims (9)

An element body having a stack of a plurality of sheets; And
A gap layer interposed between the sheets of the element body and made of a metal-glass composite material,
Wherein the metal of the metal-glass composite material comprises iron-based crystalline metal particles. delete The method according to claim 1,
Wherein the iron-based crystalline metal particles are Fe-Si-Cr crystalline metal particles. The method according to claim 1,
Wherein the metal of the metal-glass composite material has a maximum particle diameter of 10 mu m or less. The method according to claim 1,
Wherein the glass has a -Si-O-Si-O- structure as a main bonding structure. The method according to claim 1,
Wherein the metal-glass composite material has a glass content of 45 wt% to 75 wt% with respect to the composite material. The method according to claim 1,
Wherein the metal content of the metal-glass composite material is 25 wt% or more with respect to the composite material. The method according to claim 1,
An inner electrode disposed on the sheets; And
And an external electrode electrically connected to the internal electrode at both end surfaces of the element body. Preparing a metal-glass composite sheet for producing a gap layer by filming a metal-glass composite made of crystalline base metal particles and glass;
Fabricating magnetic sheets having internal electrodes formed on their surfaces;
Inserting the metal-glass composite sheet between the magnetic sheets to form a laminate, thereby fabricating a device body; And
And forming external electrodes electrically connected to the internal electrodes at both ends of the element body.

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