Coil component

A coil component includes a body; a support substrate embedded in the body; a coil portion disposed on the support substrate, and having an end portion exposed to a surface of the body; and an external electrode disposed on the surface of the body, and in contact with and connected to the end portion of the coil portion. An interface between the end portion of the coil portion and the external electrode, and an interface between the surface of the body and the external electrode are located on levels different from each other.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims benefit of priority to Korean Patent Application No. 10-2019-0089408 filed on Jul. 24, 2019 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates to a coil component.

BACKGROUND

An inductor, a coil component, is a representative passive electronic component used together with a resistor and a capacitor in electronic devices.

In accordance with the implementation of high performance and miniaturization in electronic devices, coil components used in electronic devices have increased in number and decreased in size.

In the case of a general thin film type inductor, a plurality of coil portion are formed on a large-area substrate, a magnetic composite sheet is stacked, and then diced to manufacture a body of individual components in a batch.

After the dicing process, a surface of the body is polished to remove contaminants remaining on the surface of the body (e.g., an insulating material and burrs of the conductor, and the like), and as a size of the body is reduced, difficulty in the polishing process becomes gradually higher.

SUMMARY

An aspect of the present disclosure is to provide a coil component that can omit a polishing process.

Another aspect of the present disclosure is to provide a coil component capable of improving coupling reliability between an end portion of the coil portion and the external electrode.

According to an aspect of the present disclosure, a coil component is provided. The coil component includes a body; a support substrate embedded in the body; a coil portion disposed on the support substrate, and having an end portion exposed to a surface of the body; and an external electrode disposed on the surface of the body, and in contact with and connected to the end portion of the coil portion. An interface between the end portion of the coil portion and the external electrode and an interface between the surface of the body and the external electrode are located on levels different from each other.

According to an aspect of the present disclosure, a coil component is provided. The coil component includes a body; a support substrate embedded in the body; a coil portion disposed on the support substrate, and having an end portion exposed to a surface of the body; and an external electrode disposed on the surface of the body, and in contact with and connected to the end portion of the coil portion. A surface roughness of one surface of the end portion exposed from the surface of the body is higher than a surface roughness of another surface of the end portion of the coil portion embedded in the body.

According to an aspect of the present disclosure, a coil component is provided. The coil component includes a body; a support substrate embedded in the body; a coil portion disposed on the support substrate, and having an end portion exposed to a surface of the body; and an external electrode disposed on the surface of the body, and in contact with and connected to the end portion of the coil portion. A surface roughness of the interface between the end portion of the coil portion and the external electrode is higher than a surface roughness of the interface between the surface of the body and the external electrode.

DETAILED DESCRIPTION

Hereinafter, embodiments of the present disclosure will be described as follows with reference to the attached drawings. The terms used in the exemplary embodiments are used to simply describe an exemplary embodiment, and are not intended to limit the present disclosure. A singular term includes a plural form unless otherwise indicated. The terms, “include,” “comprise,” “is configured to,” etc. of the description are used to indicate the presence of features, numbers, steps, operations, elements, parts or combination thereof, and do not exclude the possibilities of combination or addition of one or more features, numbers, steps, operations, elements, parts or combination thereof. Also, the term “disposed on,” “positioned on,” and the like, may indicate that an element is positioned on or beneath an object, and does not necessarily mean that the element is positioned on the object with reference to a gravity direction.

The term “coupled to,” “combined to,” and the like, may not only indicate that elements are directly and physically in contact with each other, but also include the configuration in which the other element is interposed between the elements such that the elements are also in contact with the other component.

Sizes and thicknesses of elements illustrated in the drawings are indicated as examples for ease of description, and exemplary embodiments in the present disclosure are not limited thereto.

In the drawings, an L direction is a first direction or a length direction, a W direction is a second direction or a width direction, a T direction is a third direction or a thickness direction.

In the descriptions described with reference to the accompanied drawings, the same elements or elements corresponding to each other will be described using the same reference numerals, and overlapped descriptions will not be repeated.

In electronic devices, various types of electronic components may be used, and various types of coil components may be used between the electronic components to remove noise, or the like.

In other words, in electronic devices, a coil component may be used as a power inductor, a high frequency (HF) inductor, a general bead, a high frequency (GHz) bead, a common mode filter, and the like.

FIGS.1and2are views schematically illustrating a coil component viewed from a lower side according to an embodiment of the present disclosure, respectively.FIG.3is a view schematically illustrating what is seen in the direction A ofFIG.1.FIGS.4and5are enlarged views of region C ofFIG.3, respectively.FIG.6is a view schematically illustrating what is seen in the direction B ofFIG.2.FIGS.7and8are enlarged views of region F ofFIG.6, respectively. Meanwhile, for clarity,FIG.1mainly illustrates the exterior of the coil component according to the present embodiment, andFIG.2mainly illustrates an internal structure of the present embodiment by omitting some components fromFIG.1. In addition, for the sake of clarity,FIG.3mainly illustrates the internal structure as viewed from the direction A inFIG.1.

Referring toFIGS.1to8, a coil component1000according to an embodiment of the present disclosure may include a body100, a support substrate200, a coil portion300, an insulating film400, and external electrodes500and600. The support substrate200includes a support portion210and end portions221and222. The coil portion300includes coil patterns311and312, lead-out patterns321and322, auxiliary lead-out patterns331and332, and a via340.

The body100forms an exterior of the coil component1000according to the present embodiment, and embeds the support substrate200, the coil portion300, and the insulating film400therein.

The body100may have a hexahedral shape as a whole.

Referring toFIG.1, The body100includes a first surface101and a second surface102facing each other in a longitudinal direction L, a third surface103and a fourth surface104facing each other in a width direction W, and a fifth surface105and a sixth surface106facing each other in a thickness direction T. Each of the first to fourth surfaces101,102,103, and104of the body100corresponds to a wall surface of the body100connecting the fifth surface105and the sixth surface106of the body100. Hereinafter, both end surfaces of the body100may mean the first surface101and the second surface102of the body and both side surfaces of the body100may mean the third surface103and the fourth surface104of the body100. In addition, one surface and the other surface of the body100may mean the sixth surface106and the fifth surface105of the body100, respectively.

As an example, the body100may be formed such that the coil component1000according to the present embodiment in which external electrodes500and600are formed to be described later has a length of 1.0 mm, a width of 0.6 mm, and a thickness of 0.8 mm, but is not limited thereto. Meanwhile, since the numerical values described above are merely numerical values on design that do not reflect process errors and the like, it should be considered that they are within the scope of the present disclosure to an extent that process errors may be recognized.

The body100may include a magnetic material and a resin. As a result, the body100has magnetic properties. The body100may be formed by stacking one or more magnetic composite sheets including a resin and a magnetic material dispersed in the resin. However, the body100may have a structure different from the structure in which a magnetic material is dispersed in a resin. For example, the body100may be formed of a magnetic material such as a ferrite.

The magnetic material may be a ferrite or magnetic metal powder.

The ferrite powder may include, for example, at least one or more materials among a spinel ferrite such as an Mg—Zn ferrite, an Mn—Zn ferrite, an Mn—Mg ferrite, a Cu—Zn ferrite, an Mg—Mn—Sr ferrite, an Ni—Zn ferrite, and the like, a hexagonal ferrite such as a Ba—Zn ferrite, a Ba—Mg ferrite, a Ba—Ni ferrite, a Ba—Co ferrite, a Ba—Ni—Co ferrite, and the like, a garnet ferrite such as a Y ferrite, and a Li ferrite.

The magnetic metal powder may include any one or more elements selected from a group consisting of iron (Fe), silicon (Si), chromium (Cr), cobalt (Co), molybdenum (Mo), aluminum (Al), niobium (Nb), copper (Cu), and nickel (Ni). For example, the magnetic metal powder may be any one or more materials among a pure iron powder, a Fe—Si alloy powder, a Fe—Si—Al alloy powder, a Fe—Ni alloy powder, a Fe—Ni—Mo alloy powder, Fe—Ni—Mo—Cu alloy powder, a Fe—Co alloy powder, a Fe—Ni—Co alloy powder, a Fe—Cr alloy powder, a Fe—Cr—Si alloy powder, a Fe—Si—Cu—Nb alloy powder, a Fe—Ni—Cr alloy powder, and a Fe—Cr—Al alloy powder.

The magnetic metal powder may be amorphous or crystalline. For example, the magnetic metal powder may be Fe—Si—B—Cr based amorphous alloy powder, but is not limited thereto.

The ferrite and the magnetic metal powder may have an average diameter of about 0.1 μm to 30 μm, respectively, but are not limited thereto.

The body100may include two or more types of magnetic materials dispersed in a resin. Here, the notion that different kinds of magnetic materials may indicate that the magnetic material dispersed in the resin is distinguished from each other by at least one of an average diameter, a composition, crystallinity, and a shape.

The resin may include one of an epoxy, a polyimide, a liquid crystal polymer, or mixture thereof, but is not limited thereto.

The body100may include a core110penetrating through an inside the coil portion300and the support substrate200to be described later. The core110may be formed by filling a through hole formed inside of the support substrate200and the coil portion300with a magnetic composite sheet, but is not limited thereto.

The support substrate200is embedded in the body100. Specifically, the support substrate200is embedded in the body100to be perpendicular to one surface106of the body100. Therefore, the coil portion300disposed on the support substrate200is disposed to be perpendicular to, or, or substantially perpendicular to, one surface106of the body100. That is, winding axes of each of coil patterns311and312of the coil portion300may be parallel to, or substantially parallel to, one surface106of the body100. The term, “substantially,” reflects consideration of recognizable errors which may occur during manufacturing or measurement.

The support substrate200includes a support portion210and end portions221and222. The support portion210supports coil patterns311and312to be described later. The first end portion221supports a first lead-out pattern321and a first auxiliary lead-out pattern331. The second end portion222supports a second lead-out pattern322and a second auxiliary lead-out pattern332. The support portion210and the end portions221and222may be processed from one insulating material and may be integrally formed without boundaries therebetween, but are not limited thereto.

The support substrate200may be formed of an insulating material including a thermosetting insulating resin such as an epoxy resin, a thermoplastic insulating resin such as a polyimide, or a photosensitive insulating resin, or may be formed of an insulating material including such an insulating resin and a reinforcing material such as a glass fiber and an inorganic filler. For example, the support substrate200may be formed of an material such as prepreg, ajinomoto build-up film (ABF), FR-4, a bismaleimide triazine (BT) resin, a photoimageable dielectric (PID), a copper clad laminate (CCL), and the like, but is not limited thereto.

As an inorganic filler, at least one or more materials selected from a group consisting of silica (SiO2), alumina (Al2O3) silicon carbide (SiC), barium sulfate (BaSO4), talc, mud, a mica powder, aluminium hydroxide (Al(OH)3), magnesium hydroxide (Mg(OH)2), calcium carbonate (CaCO3), magnesium carbonate (MgCO3), magnesium oxide (MgO), boron nitride (BN), aluminum borate (AlBO3), barium titanate (BaTiO3), and calcium zirconate (CaZrO3) may be used.

When the support substrate200is formed of an insulating material including a reinforcing material, the support substrate200may provide improved stiffness. When the support substrate200is formed of an insulating material which does not include a glass fiber, the support substrate200may reduce a width of the coil component1000according to the present embodiment by reducing a thickness of the entire coil portion300.

The coil portion300is disposed on the support substrate200, and an end portion thereof is exposed to the surface of the body100. The coil portion300is embedded in the body100to exhibit characteristics of the coil component. For example, when the coil component1000of the present embodiment is utilized as a power inductor, the coil portion300may serve to stabilize a power supply of the electronic device by storing an electric field as a magnetic field and maintaining an output voltage.

The coil portion300is formed on at least one of both surfaces of the support substrate200facing each other, and forms at least one turn. In the present embodiment, the coil portion300includes first and second coil patterns311and312respectively disposed on both surfaces of the support portion210facing each other in the width direction W of the body100and facing each other, a first lead-out pattern321and a first auxiliary lead-out pattern331respectively disposed on both surfaces of the first end portion221and facing each other, and a second lead-out pattern322and a second auxiliary lead-out pattern332respectively disposed on both surfaces of the second end portion222and facing each other. In addition, the coil portion300includes a via340penetrating through the support portion210to connect the first and second coil patterns311and312to each other.

Each of the first coil pattern311and the second coil pattern312may be formed to have a planar spiral shape having at least one turn around a core110as an axis. As an example, based on the direction ofFIG.2, the first coil pattern311may form at least one turn around the core110on one surface of the support portion210as an axis. The second coil pattern312may form at least one turn around the core110on the other surface of the support portion210as an axis.

Referring toFIGS.2,3, and6, the first lead-out pattern321is disposed on one surface of the first end portion221and connected to the first coil pattern311, and is exposed to one end surface101of the body100and one surface106of the body100. The second lead-out pattern322is disposed on the other surface of the second end portion222and connected to the second coil pattern312, and is exposed to the other end surface102of the body100and one surface106of the body100. That is, the first and second lead patterns321and322having an L shape are entirely embedded in the body100.

When the first lead-out pattern321is continuously exposed to the first surface101and the sixth surface106of the body100, a contact area with the first external electrode500, to be described later, may increase, and thus a coupling force therebetween may increase. When the second lead-out pattern322is continuously exposed to the second surface102and the sixth surface106of the body100, a contact area with the second external electrode600, to be described later, may increase, and thus a coupling force therebetween may increase.

Referring toFIGS.2,3, and6, the first auxiliary lead-out pattern331is disposed on the other surface of the first end portion221so as to correspond to the first lead-out pattern321, and is spaced apart from the second coil pattern312. The first auxiliary lead-out pattern331and the first lead-out pattern321are connected to each other by a connection via penetrating through the first end portion221. The second auxiliary lead-out pattern332is disposed on one surface of the second end portion222so as to correspond to the second lead-out pattern322, and spaced apart from the first coil pattern311. The second auxiliary lead-out pattern332and the second lead-out pattern332are connected to each other by a connection via penetrating through the second end portion222. Coupling reliability between the external electrodes500and600and the coil portion300may increase due to the first and second auxiliary lead-out patterns331and332.

The first coil pattern311and the first lead-out pattern321may be integrally formed such that a boundary is formed therebetween. The second coil pattern312and the second lead-out pattern322may be integrally formed such that no boundary is formed therebetween. However, this is merely an example, and thus, the above-described configurations are not excluded from the scope of the present disclosure in the case the boundaries are formed at different stages.

At least one of the coil patterns311and312, the lead-out patterns321and322, the auxiliary lead-out patterns331and332, and the via340may include at least one conductive layer.

For example, when the first coil pattern311, the first lead-out pattern321, the second auxiliary lead-out pattern332, and the via340are formed on one surface of the substrate200by plating, each of the first coil pattern311, the first lead-out pattern321, the second auxiliary lead-out pattern332, and the via340may include a seed layer and an electroplating layer. The seed layer may be formed by a vapor deposition method such as electroless plating or sputtering. Each of the seed layer and the electroplating layer may have a single layer structure or a multilayer structure. The electroplating layer having a multilayer structure may be formed in a conformal film structure in which one electroplating layer covers the other electroplating layer, and may be formed in a shape in which the other electroplating layer is stacked only on one surface of the one electroplating layer. The seed layer of the first coil pattern311and the seed layer of the via340may be integrally formed so as not to form a boundary therebetween, but is not limited thereto. The electroplating layer of the first coil pattern311and the electroplating layer of the via340may be integrally formed so as not to form a boundary therebetween, but is not limited thereto.

Each of the coil patterns311and312, the lead-out patterns321and322, and the auxiliary lead-out patterns331and332may be formed of a conductive material such as copper (Cu), aluminum (Al), silver (Ag), tin (Sn), gold (Au), nickel (Ni), lead (Pb),titanium (Ti), molybdenum (Mo) or alloys thereof, but a material thereof is not limited thereto. As a non-limiting example, the first coil pattern311may include a seed layer including molybdenum (Mo) and a plating layer disposed on the seed layer and including copper (Cu).

An insulating film400is disposed between each of the support substrate200and the coil portion300and the body100. In the present embodiment, since the body100includes magnetic metal powder, the insulating film400is disposed between the coil portion300and the body100to insulate the coil portion300. The insulating film400may be formed of parylene, but is not limited thereto.

The external electrodes500and600are disposed to be spaced apart from each other on one surface106of the body100, and are connected to the first and second lead-out patterns321and322, respectively. The first external electrode500covers the first lead-out pattern321to be in contact with the first lead-out pattern321, and the second external electrode600covers the second lead-out pattern322to be in contact with the second lead-out pattern322.

The external electrodes500and600electrically connect the coil component1000to the printed circuit board, or the like, when the coil component1000according to the present embodiment is mounted on the printed circuit board, or the like. As an example, the coil component1000according to the present embodiment may be mounted such that the sixth surface106of the body100faces the upper surface of the printed circuit board. Since the external electrodes500and600are disposed to be spaced apart from each other on the sixth surface106of the body100, the connection portion of the printed circuit board may be electrically connected.

The external electrodes500and600include a first conductive layer10disposed on the body100, and in direct contact with the body100, the lead-out patterns321and322, and the auxiliary lead-out patterns331, and332a second conductive layer20disposed on the first conductive layer10and covering the first conductive layer10, respectively. Each of the first conductive layer10and the second conductive layer20may be a conductive resin layer or a plating layer. The conductive resin layer may be formed by printing a conductive paste and curing the paste. The conductive paste may include any one or more conductive metals selected from a group consisting of copper (Cu), nickel (Ni), and silver (Ag) and a thermosetting resin. The plating layer may include any one or more selected from a group consisting of copper (Cu), nickel (Ni), and tin (Sn).

The interface between the end portion of the coil portion300and the external electrodes500and600and the interface between the surface of the body100and the external electrodes500and600may be located at different levels.

Referring toFIGS.3to8, levels D and D′ of the interface between the first lead-out pattern321and the first external electrode500exposed to the first surface101of the body100is different from a level E of the interface between the first surface101of the body100and the first external electrode500. A level of the interface may mean an average level. This will be hereinafter described.

The thin film coil component includes a process that proceeds to a large area substrate, a process of dicing the large area substrate to a size corresponding to the body of individual components, and a process that proceeds to the body of the individual components. Meanwhile, at least a portion of the material constituting the substrate, the magnetic composite sheet, and the coil portion during the dicing process may be extended and disposed to the surface of the individual body by being pushed by physical properties such as ductility and elasticity of the material, pressure of the dicing blade in the dicing process, and the like. When the external electrode is formed on the surface of the body in such a state, there is a possibility that a coupling force between each of the body and the end portion of the coil portion and the external electrode is lowered, and there is a possibility of poor appearance based on the final product. Therefore, in the related art, a polishing process is performed to remove the above-mentioned foreign substances remaining on the surface of the body after the cutting process. However, as the size of the body gradually decreases, it may be difficult to perform the above-mentioned polishing process. In setting a level of the surface of the body that is a basis of the polishing process, even if an error of the same level, the error may be in a range that is unacceptable for a body of a relatively small size. In addition, in setting a degree of polishing (polishing thickness), even if an error of the same level, the error may be in a range that is unacceptable for a body of a relatively small size. Therefore, as the size of the body decreases, a process error in the above-described process must be more precisely controlled, but it may have limitations unless a polishing equipment is changed.

In the present disclosure, it is intended to overcome limitation of polishing that occurs as the size of the body becomes smaller. That is, in the present disclosure, a polishing process itself is eliminated. Specifically, the first lead-out pattern321, an end portion of the coil portion300, is subjected to an acid treatment on the exposed surface exposed to the surface of the body100. Burr of the first lead-out pattern321extending onto the surface of the body100during the dicing process due to ductility may be removed.

An acid treatment may be performed using an etchant reacting to a material forming the first lead-out pattern321. For example, when the first lead-out pattern321is made of copper (Cu), acid treatment may be performed using a copper etchant reacting to copper (Cu). Due to the acid treatment, a surface roughness of the exposed surface of the first lead-out pattern321may be higher than a surface roughness of the other surface of the first lead-out pattern321. The other surface of the first lead-out pattern321may be a surface which is not exposed from the body and which is not subjected to the acid treatment. Such a surface may be embedded in the body100. In addition, the surface roughness of the exposed surface of the first lead-out pattern321may be higher than the surface roughness of the surface of the body100, such that a surface roughness of the interface between the first lead-out pattern321and the first external electrode500may be higher than a surface roughness of the interface between the surface of the body100and the first external electrode500.

Referring toFIG.4, an interface between the first lead-out pattern321and the first external electrode500may be located at a lower level than an interface between the surface of the body100and the external electrode500(D<E), with respect to a portion, for example, a plane, inside the coil component1000. After the dicing process, the surface of the body100and the exposed surface of the first lead-out pattern321are located at substantially the same level. By removing a portion of the first lead-out pattern321by acid treatment, after the acid treatment, an average level D of the exposed surface of the first lead-out pattern321may be lower than an average level E of the surface of the body100. Therefore, an interface between the first lead-out pattern321and the first external electrode500may be located on a level lower than an interface between the surface of the body100and the external electrode500. A difference in an average level (difference in E and D) between the exposed surface of the first lead-out pattern321and the surface of the body100may be adjusted by acid treatment conditions such as an acid treatment time. An average level may be determined by, for example, a surface profile measurement tool such as an atomic force microscope, by a technique recognized by those skilled in the art. An average level may be an average of distances of measured points of a region of interested to a reference plane.FIG.4shows an example in which a portion, burr of the first lead-out portion321extending to the surface of the body100, is all removed.

Referring toFIG.5, the interface between the first lead-out pattern321and the first external electrode500may be located on a level higher than the interface between the surface of the body100and the external electrode500(D′>E). This corresponds to a case in which a portion, burr of the first lead-out portion321extending to the surface of the body100, is left without being entirely removed, and an etching amount is relatively smaller than the case inFIG.4. In the case ofFIG.5, it is possible to significantly reduce the contact are between dissimilar materials (contact area between the external electrode and the body). That is,FIG.5shows a case in which a portion burr of the first lead-out portion321extending onto the surface of the body100is intentionally partially left.

Meanwhile, the description has been focused on the first lead-out pattern321, but the same description may be applied to the first auxiliary lead-out pattern331. As a result, in the coil component according to the present embodiment, as illustrated inFIGS.7and8, the exposed surface of the first auxiliary lead-out pattern331may have a difference in surface roughness and a level difference of the interface between the first external electrodes500,as compared with the surface of the body100. The description ofFIG.4may be applied toFIG.7, and the description ofFIG.5may be applied toFIG.8. In addition, the above description may be equally applied to the exposed surfaces of the second lead-out pattern322and the auxiliary lead-out patterns331and333.

In addition, although the above description has been made on the premise that a portion, burr of the first lead-out portion321, remains on the surface of the body100, the portion, burr of the first lead-out portion321, may extend to the surface of the body100and/or the exposed surface of the first end portion221in a processing direction of a dicing blade in the dicing process. The same may be also applied to the second lead-out portion321and the auxiliary lead-out portion331and332.

As set forth above, according to the present disclosure, a polishing process may be omitted when manufacturing components.

In addition, according to the present disclosure, coupling reliability between the end portion of the coil portion and the external electrode may be improved.