KR20180116604A - Inductor and manufacturing method of the same - Google Patents

Abstract

According to an embodiment of the present invention, an inductor can reduce a parasitic capacitance to secure SRF characteristics. The inductor comprises: a body including an upper surface, a lower surface facing the upper surface, and a side surface connecting the upper surface and the lower surface, and having a coil unit arranged therein; and first and second external electrodes formed on the lower surface of the body. The coil unit includes: a support member horizontally arranged on the lower surface of the body; and first and second coil patterns respectively formed on upper and lower surfaces of the support member, wherein the first external electrode is electrically connected to a first coil pattern by a first via penetrating from the lower surface of the body to the first coil pattern, and the second external electrode is electrically connected to a second coil pattern by a second via penetrating from the lower surface of the body to the second coil pattern.

Description

[0001] INDUCTOR AND MANUFACTURING METHOD OF THE SAME [0002]

The present invention relates to an inductor and a method of manufacturing the same.

Resonance refers to a frequency selection characteristic that concentrates energy at a specific frequency and selects or filters only the corresponding frequency. In terms of energy, an inductance component and a capacitance component coexist at the same time, .

In the case of inductors and capacitors, if the characteristic frequency is exceeded, the inductor will not function as a capacitor, and the capacitor will operate as an inductor. The frequency point, which does not play the original role, is equal to the resonance point and is called a self resonance frequency (SRF).

As the switching frequency of a DC-DC converter increases, there is a growing demand for inductors in which SRF characteristics have moved to high frequencies. Parasitic capacitance (Cp) must be reduced to implement an SRF-enhanced inductor.

The parasitic capacitance in the inductor can occur mainly between the coil and the coil, between the coil and the external electrode, and can cause the resonance at the high frequency, thereby reducing the SRF characteristic.

Therefore, there is a need for a method of reducing the parasitic capacitor of the inductor to secure SRF characteristics.

Korean Patent Registration No. 10-1412816 Korean Patent Laid-Open Publication No. 2015-0019730

The present invention relates to an inductor capable of reducing parasitic capacitance and securing SRF characteristics, and a manufacturing method thereof.

According to an embodiment of the present invention, there is provided a body having a top surface, a bottom surface opposed to the top surface, and a side surface connecting the top surface and the bottom surface, And first and second external electrodes formed on a lower surface of the body, wherein the coil portion includes a support member horizontally disposed on a lower surface of the body, first and second external electrodes formed on upper and lower surfaces of the support member, Wherein the first outer electrode is electrically connected to the first coil pattern by a first via passing from the lower surface of the body to the first coil pattern and the second outer electrode is electrically connected to the lower surface of the body, And the second coil pattern is electrically connected to the second coil pattern by a second via passing through the second coil pattern.

According to another embodiment of the present invention, there is provided a method of manufacturing a semiconductor device, comprising: forming a coil part including a support member, first and second coil patterns formed on upper and lower surfaces of the support member; Forming a body by laminating a magnetic sheet on top and bottom of the coil part; Forming a first via hole to reach the first coil pattern on one side of the body and forming a second via hole on the one side of the body to reach the second coil pattern; Filling the first and second via holes with a metal material to form first and second vias; And forming first and second external electrodes to be connected to the first and second vias on one side of the body, respectively.

According to an embodiment of the present invention, parasitic capacitance can be reduced to improve SRF characteristics.

1 is a perspective view of an inductor including a coil portion according to an embodiment of the present invention.
2 is a cross-sectional view taken along a line I-I 'in Fig.
FIG. 3 is a graph showing a ripple according to an output voltage of an inductor of a comparative example and an inductor according to an embodiment of the present invention (green: embodiment, red: comparative example).
FIG. 4 is a graph showing the FFT results of the inductor of the comparative example and the inductor of the embodiment of the present invention (green: example, red: comparative example).

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings. In the drawings, the shapes and sizes of elements and the like can be exaggerated for clarity.

The fact that any component is horizontal or parallel to another component means that both components are not completely horizontal or parallel to each other, but are substantially horizontal or parallel to consideration of manufacturing tolerances.

Hereinafter, an inductor according to the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a perspective view of an inductor including a coil part according to an embodiment of the present invention, and FIG. 2 is a sectional view taken along the line I-I 'of FIG.

1 and 2, the inductor 100 according to an embodiment of the present invention includes a top surface, a bottom surface facing the top surface, and a side surface connecting the top surface and the bottom surface, body; And first and second external electrodes formed on a lower surface of the body, wherein the coil portion includes a support member horizontally disposed on a lower surface of the body, first and second external electrodes formed on upper and lower surfaces of the support member, Wherein the first outer electrode is electrically connected to the first coil pattern by a first via passing from the lower surface of the body to the first coil pattern and the second outer electrode is electrically connected to the lower surface of the body, The second coil pattern is electrically connected to the second coil pattern by a second via passing through the second coil pattern.

The body 50 forms the appearance of the inductor. The body may have one surface, a surface facing the one surface, and surfaces connecting the one surface and the other surface. L, W and T shown in Fig. 1 indicate the longitudinal direction, the width direction and the thickness direction, respectively. The body 50 may be in the form of a hexahedron including upper and lower surfaces facing each other in the lamination direction (thickness direction) of the coil layer, and a front surface facing the longitudinal direction and a front surface facing the width direction, The lower surface (the other surface) of the body may be a seal scene. The corners where each face meets can be rounded by grinding or the like.

The body 50 includes a magnetic material that exhibits magnetic properties.

The body 50 may be formed by forming a coil portion and then laminating a sheet containing a magnetic material on the upper and lower portions thereof, and then pressing and curing the sheet. The magnetic material may be, for example, a resin containing ferrite or metal magnetic particles.

The body 50 may be in the form of ferrite or metal magnetic particles dispersed in a resin.

The ferrite may include a material such as Mn-Zn ferrite, Ni-Zn ferrite, Ni-Zn-Cu ferrite, Mn-Mg ferrite, Ba ferrite or Li ferrite.

The metal magnetic particles may include at least one selected from the group consisting of iron (Fe), silicon (Si), chrome (Cr), aluminum (Al), and nickel (Ni) -B-Cr amorphous metal, but it is not necessarily limited thereto. The diameter of the metal magnetic particles may be about 0.1 占 퐉 to 30 占 퐉.

The resin may be a thermosetting resin such as an epoxy resin or a polyimide resin.

The coil unit plays a role of performing various functions in the electronic device through the characteristics expressed from the coil of the inductor 100. For example, the inductor 100 may be a power inductor. In this case, the coil unit may store electricity in the form of a magnetic field to maintain the output voltage and stabilize the power supply.

The coil portion includes first and second coil patterns 40 formed on upper and lower surfaces of the support member 20, respectively. The first and second coil patterns 40 are coil layers arranged to face each other with respect to the support member 20. The ground member 20 can be disposed horizontally on the lower surface of the body 50, that is, on the mounting surface.

The first and second coil patterns 41 and 42 may be formed using a photolithography process or a plating process.

The first and second coil patterns may be formed in a spiral shape and are electrically connected through an inner via 45 formed through the support member.

The first and second coil patterns 41 and 42 may be formed of a metal having excellent electrical conductivity. For example, silver (Ag), palladium (Pd), aluminum (Al), nickel (Ni) And may be formed of titanium (Ti), gold (Au), copper (Cu), platinum (Pt), or an alloy thereof.

Generally, the inductor structure includes a body made of a magnetic material and an external electrode formed to surround both sides of the body, and a center line in the thickness direction of the body is the same as a center line of the coil part, that is, a center line of the supporting member. At this time, parasitic capacitances are generated between the external electrodes formed on the upper and lower parts of the body and the coil pattern, thereby lowering the SRF characteristics of the inductor.

The inductor 100 according to the present invention includes first and second external electrodes 81 and 82 formed on the bottom surface of the body, and the first and second external electrodes are formed in the body, The parasitic capacitance between the outer electrode and the coil is reduced and the total parasitic capacitance can be greatly reduced by including the first and second vias 81a and 82a connected to the two coil patterns 41 and 42, The characteristics can be improved.

The first and second vias 81a and 82a may be formed from the lower surface of the body to the first and second coil patterns so as to be in contact with the first and second coil patterns.

The first outer electrode 81 is electrically connected to the first coil pattern 41 by a first via 81a extending from the lower surface of the body to the first coil pattern 41, The electrode 82 is electrically connected to the second coil pattern 42 by a second via 82a penetrating from the lower surface of the body to the second coil pattern 42. [

The first and second coil patterns 41 and 42 are connected to the first and second vias 81a and 82a so that the first and second coil patterns 41 and 42 are connected to the surface of the body It may not be exposed. Since the first and second coil patterns 41 and 42 are not exposed to the surface of the body, the margin of the body 50 or the thickness of the insulating layer 70 can be minimized. This can increase the volume of the body that affects performance in the inductor.

The first vias 81a may be connected to the first coil pattern 41 through the support member.

The first and second external electrodes 81 and 82 are electrically connected to the lead terminals of the first and second coil patterns 41 and 42 exposed on both sides of the body 50.

The first and second external electrodes 81 and 82 serve to electrically connect a coil part in the inductor to an electronic device when the inductor is mounted on the electronic device.

The first and second external electrodes 81 and 82 may be formed using a conductive paste containing a conductive metal such as Cu, Ni, Sn, Ag) or an alloy thereof.

The first and second external electrodes may be a plating layer and the plating layer may include at least one selected from the group consisting of nickel (Ni), copper (Cu), and tin (Sn) (Ni) layer and a tin (Sn) layer may be sequentially formed.

Since the first and second external electrodes are formed on the lower surface, the parasitic capacitance between the external electrode and the coil is reduced to improve the SRF characteristics of the inductor. Also, since the area of the external electrode is reduced by connecting the vias and the coil pattern in the inside, the volume of the body can be increased and thus a high inductance or a low DC resistance (Rdc) can be obtained.

Particularly, as described above, since the first and second coil patterns 41 and 42 are not exposed to the surface of the body, the margin of the body 50 or the thickness of the insulating layer 70 can be minimized. This can further increase the volume of the body that affects performance in the inductor.

Table 1 below shows the volume increase rate of the inductor according to one embodiment of the present invention.

In Table 1, 3216 means an inductor having a size of 3.2 mm x 1.6 mm.

3216 2012 1608 1005 0603 Volume growth rate (%) 167.70 139.32 149.75 134.94 144.15

The volume growth rate in Table 1 refers to the increased rate of body volume that actually affects the performance of the inductor in the overall inductor size.

Referring to Table 1, it can be confirmed that the volume increase rate is 130% or more by disposing the external electrode only on the bottom surface of the body and preventing the first and second coil patterns 41 and 42 from being exposed to the surface of the body. Depending on the volume of the body, the inductor according to an embodiment of the present invention may have a high inductance or a low DC resistance (Rdc).

FIG. 3 is a graph showing a ripple according to a conventional inductor and an output voltage of the inductor according to an embodiment of the present invention. FIG. 4 is a graph showing the FFT result of a conventional inductor and an inductor according to an embodiment of the present invention. As shown in the graph.

Referring to FIG. 3 and FIG. 4, it can be seen that, in the case of green, the embodiment of the present invention is a result value for a conventional inductor in case of red, and that noise in the conventional inductor is much amplified as compared with the embodiment of the present invention .

In particular, as shown in FIG. 4, the conventional inductor shows a significant noise phenomenon in the range of high frequency as compared with the embodiment of the present invention.

The support member 20 is not particularly limited as long as it can support the first and second coil patterns 41 and 42. For example, the support member 20 may be formed of a copper clad laminate (CCL), polypropylene glycol (PPG ) Support member, a ferrite support member, or a metal-based soft magnetic support member. It may also be an insulating supporting member made of an insulating resin. As the insulating resin, a thermosetting resin such as an epoxy resin, a thermoplastic resin such as polyimide, or a resin impregnated with a reinforcing material such as a glass fiber or an inorganic filler such as prepreg, ABF (Ajinomoto Build- Film, FR-4, bismaleimide triazine (BT) resin, and PID (Photo Imagable Dielectric) resin. From the standpoint of stiffness maintenance, an insulating supporting member including glass fiber and epoxy resin can be used, but is not limited thereto.

The central portion of the upper surface and the lower surface of the support member 20 penetrate to form a hole, and the hole may be filled with a magnetic material such as ferrite or metal magnetic particles to form a core portion. The inductance L can be improved by forming the core portion filled with the magnetic body.

The first coil pattern 41 and the second coil pattern 42 stacked on both surfaces of the support member are electrically connected through the inner vias 45 passing through the support member.

The inner via 45 may be formed by forming a through hole using a mechanical drill or a laser drill, and then filling the through hole with a conductive material by plating.

The shape and material of the inner vias 45 are not particularly limited as long as they can electrically connect the upper first coil pattern 41 and the lower second coil pattern 42 disposed on both sides of the support member 20, It does not. Here, the upper side and the lower side are determined on the basis of the stacking direction of the coil pattern in the drawing.

The inner vias 45 may be formed of a conductive material such as copper (Cu), aluminum (Al), silver (Ag), tin (Sn), gold (Au), nickel (Ni), lead (Pd) . ≪ / RTI >

An inner via 45 is formed to electrically connect the first and second coil patterns 41 and 42 formed on the upper and lower surfaces of the support member 20, can do. The larger the size of the inner vias, the larger the volume of the coil, the larger the non-magnetic region in the inductor, and the smaller the current characteristic that the inductor needs to implement There is a problem.

The cross section of the inner via 45 may be trapezoidal or hourglass-shaped.

The cross section of the inner via 45 may be in the form of an hourglass. The shape may be realized by machining the upper or lower surface of the support member, thereby reducing the width of the cross section of the inner via. The width of the cross section of the inner vias may be between 60 and 80 micrometers, but is not limited thereto.

The first and second coil patterns 41 and 42 are covered with an insulating layer (not shown) and are not in direct contact with the magnetic material forming the body.

The insulating layer serves to protect the first and second coil patterns.

The material of the insulating film may be any material that includes an insulating material. For example, the insulating material may include an insulating material used for a general insulating coating, such as an epoxy resin, a polyimide resin, a liquid crystalline polymer resin, And a known photoimageable dielectric (PID) resin may be used, but the present invention is not limited thereto.

The inductor of one embodiment of the present invention may include an insulating layer 70 formed to cover the surface of the body 50.

The insulating layer 70 may be formed on a surface other than a bottom surface of the body.

The insulating layer 70 is made of a material having an insulating property. For example, a filler can be used, and an acrylate or an epoxy capable of causing thermosetting, And the present invention is not limited thereto.

By forming the insulating layer, the parasitic capacitance generated between the inductor and other external components can be reduced.

Hereinafter, a method of manufacturing an inductor according to the present invention will be described.

A method of manufacturing a thin film inductor according to an embodiment of the present invention includes: forming a coil part including a support member, first and second coil patterns formed on upper and lower surfaces of the support member; Forming a body by laminating a magnetic sheet on top and bottom of the coil part; Forming a first via hole to reach the first coil pattern on one side of the body and forming a second via hole on the one side of the body to reach the second coil pattern; Filling the first and second via holes with a metal material to form first and second vias; And forming first and second external electrodes to be connected to the first and second vias on one side of the body, respectively.

And the first and second coil patterns are patterned on the upper surface and the lower surface of the support member.

The inner via hole may be formed in the support member, and the inner via hole may be formed by using a mechanical drill or a laser drill, but the present invention is not limited thereto. The laser drill may be, for example, a CO ₂ laser or a YAG laser.

The first and second coil patterns may be formed by performing electroless plating or sputtering on the support member to form a conductive layer, forming a resist pattern, and then performing an etching process for patterning and a resist pattern peeling process As shown in FIG.

Next, an insulating film is formed on the first and second coil patterns.

The insulating film may be a polymer polymer insulating material, for example, a phenylene based polymer, but is not limited thereto.

The insulating layer may be formed by a dipping method using a screen printing method, a spray coating method, a chemical vapor deposition (CVD) method, or a low viscosity polymer coating liquid. However, It is not.

Next, a magnetic substance sheet is laminated on upper and lower portions of the support member on which the first and second coil patterns are formed to form a body. At this time, the magnetic substance sheet can be filled in the space between the patterned insulating films on the coil pattern.

The magnetic sheet is prepared by mixing a magnetic material such as a metal magnetic powder and an organic material such as a thermosetting resin to prepare a slurry, applying the slurry onto a carrier film by a doctor blade method, sheet type.

After a plurality of magnetic sheet sheets are laminated, they are pressed and cured by a lamination method or an hydrostatic pressing method to form a magnetic body.

At this time, the magnetic sheet can be laminated so that the first and second coil patterns are not exposed to the surface of the body.

Next, first and second via holes are formed to reach the inside of the body on one side of the body.

For example, a first via hole may be formed to reach the first coil pattern on one side of the body, and a second via hole may be formed on the one side of the body to reach the second coil pattern.

The first and second via holes may be formed to expose the first and second coil patterns, and may be formed by laser processing.

The first via hole may be formed through the support member to expose the first coil pattern.

Next, the first and second vias are formed by filling the metal material from the inside of the first and second via holes to the bottom of the body. The first and second vias may be formed by a plating process.

Finally, the first and second external electrodes are formed on one surface of the body, that is, the mounting surface, so as to be connected to the first and second vias, respectively.

Here, one side of the body can be provided as a real scene, which means the lower side of the body.

Since the first and second external electrodes are formed on the bottom surface of the body, the polishing process for exposing the first and second coil patterns to the side surface of the body can be omitted.

Except for the above description, a description overlapping with the features of the coil electronic component according to the embodiment of the present invention described above will be omitted here.

The present invention is not limited by the above-described embodiments and the accompanying drawings, but is intended to be limited by the appended claims.

It will be apparent to those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. something to do.

20: support member
41, 42: first and second coil patterns
45: inner via
50: Body
55: core portion
81, 82: first and second outer electrodes
81a, 82a: first and second vias
100: inductor

Claims (13)

A body having a top surface, a bottom surface facing the top surface, and a side surface connecting the top surface and the bottom surface, the coil portion being disposed in the body; And
And first and second external electrodes formed on the bottom surface of the body,
Wherein the coil portion includes a support member horizontally disposed on a lower surface of the body, first and second coil patterns formed on upper and lower surfaces of the support member,
Wherein the first external electrode is electrically connected to the first coil pattern by a first via passing from the lower surface of the body to the first coil pattern and the second external electrode is electrically connected to the second coil pattern from the lower surface of the body, And the second coil pattern is electrically connected to the second coil pattern by a second via.
The method according to claim 1,
And the first via is connected to the first coil pattern through the support member.
The method according to claim 1,
Wherein the first and second coil patterns are not exposed to the surface of the body.
The method according to claim 1,
Wherein the first and second coil patterns are electrically connected to each other through an inner via passing through the support member.
The method according to claim 1,
And an insulating layer disposed on the upper and side surfaces of the body.
Forming a coil part including a support member, first and second coil patterns formed on upper and lower surfaces of the support member;
Forming a body by laminating a magnetic sheet on top and bottom of the coil part;
Forming a first via hole to reach the first coil pattern on one side of the body and forming a second via hole on the one side of the body to reach the second coil pattern;
Filling the first and second via holes with a metal material to form first and second vias; And
And forming first and second external electrodes on one surface of the body so as to be connected to the first and second vias, respectively.
The method according to claim 6,
And the first via hole is connected to the first coil pattern through the support member.
The method according to claim 6,
Wherein the first and second via holes are formed by laser processing.
The method according to claim 6,
In the step of forming the body,
Wherein the magnetic sheet is laminated so that the first and second coil patterns are not exposed to the surface of the body.
The method according to claim 6,
Wherein the first and second vias are formed by a plating process.
The method according to claim 6,
In the step of forming the coil portion,
Wherein the first and second coil patterns are electrically connected to each other by inner vias.
The method according to claim 6,
Wherein the first and second coil patterns are formed to be parallel to the first and second external electrodes.
The method according to claim 6,
Wherein one surface of the body is provided as a mount surface.

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