Coil electronic component

A coil electronic component includes a body including a coil portion disposed therein, and including a plurality of magnetic particles, and external electrodes connected to the coil portion. The body includes an internal region and a protective layer disposed on a surface of the internal region. A first particle of the plurality of magnetic particles included in the protective layer includes an oxide film disposed on a surface of the first particle, and a second particle, having a size greater than a size of the first particle, of the plurality of magnetic particles includes a coating layer disposed on a surface of the second particle and having a composition different from a composition of the oxide film.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims the benefit of priority to Korean Patent Application No. 10-2018-0166350 filed on Dec. 20, 2018 in the Korean Intellectual Property Office, the entire disclosure of which is incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a coil electronic component.

BACKGROUND

As electronic devices such as digital televisions, mobile phones, laptops, and the like, have been designed to have reduced sizes, a coil electronic component applied to such electronic devices has been required to have a reduced size. To meet such demand, a large amount of studies into developing various types of coil-type or thin-film type coil electronic components have been conducted.

An important consideration in developing a coil electronic component having a reduced size is to implement the same properties as before after reducing a size of a coil electronic component. To this end, it may be necessary to increase a content of a magnetic material filling a core. However, there may be a limitation in increasing a content of the magnetic material due to strength of an inductor body, changes in frequency properties caused by insulating properties, and for other reasons.

As an example of manufacturing a coil electronic component, a body may be implemented by layering sheets formed of a mixture of magnetic particles, resin, and the like, on a coil and pressuring the sheets. As the magnetic particles, ferrite, a metal, and the like, may be used. When metal magnetic metal particles are used, it may be preferable to increase a content of the particles in terms of permeability properties of a coil electronic component, but in this case, insulating properties of the body may degrade such that breakdown voltage properties may degrade.

SUMMARY

An aspect of the present disclosure is to provide a coil electronic component having improved breakdown voltage properties by improving insulating properties of a body. The coil electronic component may have improved magnetic properties while reducing a size of the body, as insulating properties of the body improves.

According to an aspect of the present disclosure, a coil electronic component may include a body including a coil portion disposed therein, and including a plurality of magnetic particles, and external electrodes connected to the coil portion. The body includes an internal region and a protective layer disposed on a surface of the internal region. A first particle of the plurality of magnetic particles included in the protective layer may include an oxide film disposed on a surface of the first particle, and a second particle, having a size greater than a size of the first particle, of the plurality of magnetic particles includes a coating layer disposed on a surface of the second particle. The coating layer may have a composition different from a composition of the oxide film and.

The coating layer disposed on the surface of the second particle may be configured as an inorganic coating layer including a P component.

The coating layer may include P-based glass.

A thickness of the coating layer may be 10 to 60 nm.

The coating layer disposed on the surface of the second particle may be configured as an atomic layer deposition layer.

The first particle may include pure iron.

The first particle may have a diameter of 5 μm or less.

The second particle may include an Fe-based alloy.

The second particle may have a diameter of 10 to 25 μm.

A thickness of the protective layer may be 4 to 40 μm.

The oxide film may include an oxide including a metal component included in the first particle.

A thickness of the oxide film may be 200 nm or less.

A partial particle of the plurality of magnetic particles included in the internal region may include an oxide film disposed on a surface of the partial particle.

The oxide film in the internal region may have a thickness less than a thickness of the oxide film of the protective layer.

An amount of the oxide film included in a unit volume of the protective layer may be higher than an amount of the oxide film included in a unit volume of the internal region.

A thickness of the oxide film of the protective layer may decrease from an exterior surface of the protective layer to the internal region.

When the protective layer includes two regions having a same thickness as each other, a thickness of the oxide film in a region adjacent to a surface of the body may be greater than a thickness of the oxide film in a region adjacent to the internal region.

According to another aspect of the present disclosure, a coil electronic component may include a body including a coil portion disposed therein, and including a plurality of magnetic particles, and external electrodes connected to the coil portion, and at least one partial particle of the plurality of magnetic particles included in the body includes an oxide film disposed on a surface of the at least one partial particle, and a thickness of the oxide film of the at least one partial particle adjacent to a surface of the body is greater than a thickness of the oxide film of the at least one partial particle adjacent to an internal region of the body.

The at least one partial particle having the oxide film on a surface thereof may have a diameter of 5 μm or less.

A thickness of the oxide film may be 200 nm or less.

DETAILED DESCRIPTION

Hereinafter, exemplary embodiments of the present disclosure will be described as follows with reference to the attached drawings.

The present disclosure may, however, be exemplified in many different forms and should not be construed as being limited to the specific exemplary embodiments set forth herein. Rather, these exemplary embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. Accordingly, shapes and sizes of the elements in the drawings can be exaggerated for clear description. Also, elements having the same function within the scope of the same concept represented in the drawing of each exemplary embodiment will be described using the same reference numeral.

FIG.1is a perspective diagram illustrating a coil electronic component according to an exemplary embodiment of the present disclosure.FIGS.2and3are cross-sectional diagrams illustrating the coil electronic component illustrated inFIG.1taken along lines I-I′ and II-II′ inFIG.1, respectively.FIGS.4and5are enlarged diagrams illustrating one regions of a body of a coil electronic component, illustrating one regions of a protective layer and an internal region.FIG.6is an enlarged diagram illustrating a second particle shown inFIGS.4and5and a coating layer thereof according to an exemplary embodiment of the present disclosure.

Referring to the diagrams, a coil electronic component100in an exemplary embodiment of the present disclosure may include a body101may include a body101, a support substrate102, a coil portion103, and external electrodes105and106, and the body101may include a plurality of magnetic particles112and212. The body101may include an internal region120and a protective layer111disposed on a surface of the internal region120. A partial particle112(hereinafter, a first particle) may include an oxide film113disposed on a surface of the first particle. A partial particle212(hereinafter, a second particle) having a size greater than a size of the first particle112may include a coating layer213having a composition different from a composition of the oxide film113and disposed on a surface of the second particle212. According to an exemplary embodiment of the present disclosure, the second particle212may be included as an essential element, but in other exemplary embodiments, the second particle212may not be provided.

The body101may seal at least portions of the support substrate102and the coil portion103, and may form an exterior of the coil electronic component100. The body101may be configured to externally expose a partial region of a lead-out pattern L. As illustrated inFIGS.4and5, the body101may include the plurality of magnetic particles112and212, and the magnetic particles112and212may be distributed in an insulating material110. The insulating material110may include a polymer component such as a high an epoxy region, a polyimide, and the like.

According to an exemplary embodiment of the present disclosure, the body101may include the magnetic particles112and212having different sizes, thereby increasing the amount of the magnetic particles112and212included in the body101. As for the first particle112having a relatively small size, the first particle112may fill a space between the second particles212. The first particle112may include pure iron, and may have a form of carbonyl iron powder (CIP), for example. A diameter d1of the first particle112may be 5 μm or less.

The oxide film113may be disposed on a surface of the first particle112. For example, as illustrated inFIGS.4and5, the oxide film113may be disposed on a surface of the first particle112included in the protective layer110in the body101, and the oxide film113may also be disposed on a surface of the first particle112included in the internal region120. Alternatively, the oxide film113may not be disposed on a surface of the first particle112included in the internal region120.FIG.4illustrates an example in which no coating layer is disposed on the first particle112which does not include the oxide film113, but an exemplary embodiment thereof is not limited thereto. A coating layer for protecting the first particle112may be formed. For example, the coating layer may be configured as an inorganic coating layer including a P component, or an atomic layer deposition layer. When a coating layer is disposed on a surface of the first particle112, the oxide film113obtained by oxidizing the first particle112and the coating layer may form a multilayer structure, and the coating layer213and the oxide film113may be formed in a mixed manner.

The oxide film113on a surface of the first particle112may be an oxide of a metal component included in the first particle112. For example, when the first particle112includes pure iron, the oxide film113may be an oxide iron (Fe2O3). Thicknesses t1and t3of the oxide film113may be 200 nm or less. According to an exemplary embodiment of the present disclosure, the oxide film113may be effectively disposed on the first particle112of a protective layer110forming an external layer of the body101by adjusting process conditions for forming the oxide film113. Accordingly, insulating properties of the protective layer110may improve. When insulating properties of the protective layer110improve, inductance properties and breakdown voltage (BDV) properties of the coil electronic component100may also improve.

Referring toFIGS.3and4, a thickness t3of the oxide film113of the internal region120may be less than the thickness t1of the oxide film113of the protective layer110. An amount of the oxide film113included in a unit volume of the protective layer110may be higher than a content of the oxide film113included in a unit volume of the internal region120in the body101. The oxide film113on a surface of the first particle112may be formed by performing a heat treatment on the body101, by exposing the body101to ozone, or the like. As the first particle112may be more actively oxidized on a surface of the body101, a greater amount of the oxide film113may be disposed on the protective layer110, an external layer of the body101, and the protective layer110may improve insulating properties of the body101. That is because, when insulating properties is vulnerable in an external layer of the body101adjacent to the external electrodes105and106, breakdown voltage may significantly decrease. Also, when the body101is ground to prevent a chipping defect, or other defects, the first particle112may be exposed from a surface of the body101, or a thickness of an insulating film on a surface of the magnetic particle112may become uneven. In this case, insulating properties of the body101may further degrade. According to an exemplary embodiment of the present disclosure, by forming the protective layer110including the oxide film113on a surface of the body101, the above-described issue may be reduced.

A size of the protective layer110may be adjusted by changing a heat treatment temperature for forming the oxide film113or an ozone concentration. According to the study performed by the inventors, when a thickness T of the protective layer110was 4 to 40 μm, improved inductance properties and breakdown voltage properties were secured. When a heat treatment temperature was excessively increased, or a heat treatment time was excessively lengthened, a thickness of the oxide film113was increase. Accordingly, although insulating properties improved, inductance property degraded. In this case, as described above, the thicknesses t1and t3of the oxide films113disposed in the protective layer110and the internal region120may be 200 nm or less.

As for the protective layer110obtained by the above-described method, a size of the oxide film113on a surface of the first particle112may be varied in different regions. For example, a thickness of the oxide film113may decrease from a surface of the protective layer110to the internal region120. Also, when the protective layer110is divided into two regions having the same thickness, a thickness of the oxide film113in a region disposed on a surface may be greater than a thickness of the oxide film113in a region disposed adjacent to the internal region120. That is because, as described above, the oxide film113may have a greater thickness on a surface of the body101.

The second particle212having a relatively great size may include an Fe-based alloy, or the like. For example, the second particle212may include a nanocrystalline particle boundary alloy having a composition of Fe—Si—B—Cr, an Fe—Ni based alloy, and the like. A diameter d2of the second particle212may be 10 to 25 μm. When a portion of the magnetic particle includes an Fe-based alloy as described above, magnetic properties such as permeability may improve, but the magnetic particle may be vulnerable to electrostatic discharge (ESD). Accordingly, a coating layer213may be disposed on a surface of the second particle212. The coating layer213may have a composition different from a composition of the oxide film113of the first particle112.

According to the study conducted by the inventors, the oxide film113was selectively formed only on a surface of the first particle112during a process of oxidizing the body101, and the oxide film was not disposed on the second particle212, or a small amount of oxide film was formed. When a small amount of oxide film is disposed on the second particle212, a thickness of the second particle212may be less than a thickness of the oxide film113of the first particle112. The oxide film of the second particle212may refer to an oxide film disposed on a surface of the second particle212or a surface of the coating layer213. When the body101is oxidized by a heat treatment process, the oxide film113started being disposed on the first particle112having a relatively small size within a temperature range of 100 to 200° C., a relatively low temperature, whereas the second particle212started being oxidized at 500° C. or higher, a temperature significantly higher than the above-mentioned temperature. In the temperature in which the second particle212is oxidized, damage may be applied to the insulating material110, and others. Accordingly, the body101may be oxidized in a temperature lower than the above-mentioned temperature, thereby selectively oxidizing the first particle112.

The coating layer213on a surface of the second particle212may be configured as an inorganic coating layer including a P component. For example, the coating layer213may include P-based glass. The P-based inorganic coating layer may include elements such as P, Zn, Si, and the like, and may include oxides of the elements. When the coating layer213is configured as a P-based inorganic coating layer, a thickness t2of the coating layer213may be 10 to 60 nm.

The coating layer213on a surface of the second particle212may also be configured as an atomic layer deposition (ALD) layer. The atomic layer deposition may be a process of uniformly coating a surface of an object in atomic layer level by surficial chemical reaction during a process of periodically supplying and discharging a reacting material. The coating layer213obtained by the above-described process may have a reduced and uniform thickness and improved insulating properties. Accordingly, even when the body101is filled with a large amount of the second particle212, insulating properties of the body101may be effectively secured. When the coating layer213is configured as an atomic layer deposition layer, a thickness of the coating layer213may be reduced such that a size of the body101may be reduced, and a thickness of the coating layer213may be 10 to 15 nm. Also, when the coating layer213is configured as an atomic layer deposition layer, the coating layer213may include alumina (Al2O3), silica (SiO2), and the like. The coating layer213may also include various materials formed by an atomic layer deposition other than the above-mentioned materials. For example, the coating layer213may include materials such as TiO2, ZnO2, HfO2, Ta2O5, Nb2O5, Sc2O3, Y2O3, MgO, B2O3, GeO2, and the like. According to exemplary embodiments of the present disclosure, as illustrated inFIG.6, the coating layer213may have a multilayer structure including an P-based inorganic coating layer213band an atomic layer deposition layer213a.

As an example of a method of manufacturing the body101, the body101may be formed by a layering process. For example, the coil portion103may be disposed on the support substrate102using a plating process, and the like, a plurality of unit laminates for manufacturing the body101may be prepared, and the unit laminates may be stacked. The unit laminates may be manufactured by making a slurry using a mixture of the magnetic particles112and212including a metal and organic materials such as a thermosetting resin, a binder, a solvent, and the like, coating a carrier film with the slurry in thickness of several tens of μm using a doctor blade method, drying the slurry, and manufacturing the unit laminates in sheet form. Accordingly, the manufactured unit laminate may include magnetic particles distributed in a thermosetting resin such as an epoxy resin, a polyimide, or the like. A plurality of the unit laminates may be formed, and the unit laminates may be stacked in an upper portion and a lower portion of the coil portion103and may be pressured, thereby implementing the body101. The oxide film113may be disposed on the magnetic particle112present in the body101through an oxidization process as described above, and in this case, a relatively thinner oxide film113may be disposed on the magnetic particle112of the internal region120, or the oxide film113may not be disposed on the magnetic particle112of the internal region120.

The other elements will be described with reference toFIGS.1to3. The support substrate102may support the coil portion103, and may be implemented as a polypropylene glycol (PPG) substrate, a ferrite substrate or a metal-based soft magnetic substrate, and the like. As illustrated in the diagram, a through-hole may be formed in a central portion of the support substrate102, penetrating the support substrate102, and the through-hole may be filled with the body101, thereby forming a magnetic core portion C. According to exemplary embodiments of the present disclosure, the support substrate102may not be provided.

The coil portion103may be disposed in the body101, and may perform various functions in an electronic device through properties implemented by coils of the coil electronic component100. For example, the coil electronic component100may be implemented as a power inductor, and in this case, the coil portion103may stabilize power by storing electricity in a form of a magnetic field and maintaining an output voltage. Coil patterns included in the coil portion103may be layered on both surfaces of the support substrate102, and may be electrically connected through a conductive via V penetrating the support substrate102. The coil portion103may be formed in spiral form, and a lead-out portion T may be included in an outermost region of the spiral form for electrical connection with the external electrodes105and106.

The coil portion103may be disposed on at least one of a first surface (an upper surface inFIG.2) and a second surface (a lower surface inFIG.2) of the support substrate102opposing each other. According to an exemplary embodiment of the present disclosure, the coil portion103may be disposed on both of the first surface and the second surface of the support substrate102, and in this case, the coil portion103may include a pad region P. Alternatively, the coil portion103may be disposed on only one of surfaces of the support substrate102. The coil pattern included in the coil portion103may be formed using a plating process used in the respective technical field, such as a pattern plating process, an anisotropic plating process, an isotropic plating process, or the like, and may be configured to have a multilayer structure using a plurality of processes among the above-mentioned processes.

The external electrodes105and106may be disposed externally on the body101and may be connected to the lead-out pattern L. The external electrodes105and106may be formed using a paste including a metal having high electrical conductivity, and the paste may be a conductive paste including one of nickel (Ni), copper (Cu), tin (Sn) or silver (Ag), or alloys thereof, for example. Each of the external electrodes105and106may further include a plating layer (not illustrated) disposed thereon. In this case, the plating layer may include one or more elements selected from a group consisting of nickel (Ni), copper (Cu), and tin (Sn). For example, a nickel (Ni) plating layer and a tin (Sn) plating layer may be formed in order.

According to the aforementioned exemplary embodiments, in the coil electronic component, breakdown voltage properties may improve as insulating properties of the body improves.